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Numerical Analysis of a Dental Zirconium Restoration and the Stresses That Occur in Dental Tissues

Numerical Analysis of a Dental Zirconium Restoration and the Stresses That Occur in Dental Tissues Hindawi Applied Bionics and Biomechanics Volume 2019, Article ID 1049306, 13 pages https://doi.org/10.1155/2019/1049306 Research Article Numerical Analysis of a Dental Zirconium Restoration and the Stresses That Occur in Dental Tissues Rosa Alicia Hernández-Vázquez , Guillermo Urriolagoitia-Sosa, Rodrigo Arturo Marquet-Rivera , Beatriz Romero-Ángeles, Octavio-Alejandro Mastache-Miranda , and G. Guillermo Urriolagoitia-Calderón Instituto Politécnico Nacional, Escuela Superior de Ingeniería Mecánica y Eléctrica, Sección de Estudios de Posgrado e Investigación, Unidad Profesional Adolfo López Mateos “Zacatenco, ” Avenida Instituto Politécnico Nacional, S/n Edificio 5, 2do. Piso, Col. Lindavista, C.P. 07320 Ciudad de México, Mexico Correspondence should be addressed to Rosa Alicia Hernández-Vázquez; alyzia.hv@esimez.mx Received 17 January 2019; Revised 25 June 2019; Accepted 13 August 2019; Published 5 September 2019 Academic Editor: Mohammad Rahimi-Gorji Copyright © 2019 Rosa Alicia Hernández-Vázquez et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. When it is about restorative dental materials, aesthetics is traditionally preferred. This has led to the selection of materials very visually similar to the enamel, but unfortunately, their mechanical properties are not similar. This often translates into disadvantages than advantages. In the present work, a comparison is made of the stresses that occur during dental occlusion (dental bit) in a healthy dental organ and those that are generated in a dental organ with a dental zirconium restoration. Numerical simulation was carried out by means of the Finite Element Method, in computational biomodels, from Cone-Beam Tomography, to obtain the stresses generated during dental occlusion. It was found that the normal and von Mises stresses generated are substantially greater in the molar with restoration compared to those produced in the healthy molar. In addition, the normal function of the enamel and dentin to disperse these stresses to prevent them from reaching the pulp is altered. Therefore, it is necessary to analyze the indiscriminate use of this restoration material and consider other aspects, in addition to aesthetics and biocompatibility for the choice of restorative materials such as biomechanical compatibility. 1. Introduction essary to consider the degree and location of the defect, the evolution time, the degree of aggressiveness, the amount of affected tissue, and the healthy tissue remaining. Today’s dentistry is focused on achieving its transformation, from being an area of therapeutic medicine to becoming a A fundamental aspect that should be considered is that preventive health area. However, it is still on track to achieve dental tissue affected by caries has undergone variations in that goal. The odontological task is mainly of restorative type. its biological, physical, chemical, and mechanical properties, This restorative nature of dentistry is due to the high inci- due to the caries process and mastication. There is evidence dence of caries and its consequences. It has been reported that, in dental tissues affected by caries, there is a stiffening that 95% of the world population suffers from or has suffered phenomenon of both the affected tissue and the healthy rem- tooth caries. The rate of caries recidivism or the restorative nant, which makes the tissues more fragile by mechanical treatment by itself is not a resolutive therapy [1]. Facing these means [2, 3]. This agrees with general dentistry knowledge aspects, the dentist must select the treatment and restorative that a dental organ with caries is more prone to fracture dur- material suitable for each patient. They should consider the ing chewing, than a healthy one. And fundamental aspects behavior of the tooth to rehabilitate and restore it considering should be considered for the selection of the type of restora- different variables, such as masticatory forces and the type of tion and restorative material to be applied. A little less than pathology that occurs. In the case of carious lesions, it is nec- 20 years ago, the use of various ceramic materials for the 2 Applied Bionics and Biomechanics sue with a greater amount of collagen than the enamel, so manufacture of dental restorations was implemented. These materials have properties with greater similarities to those it is more elastic. This tissue supports the enamel and com- of dental tissues in terms of strength, aesthetics, and biocom- pensates for its fragility preventing it from easily fracturing. In addition, the dentin is responsible for sending the loads patibility [4]. For the dental community, the hardness and resistance of and stress that are produced by the masticatory forces a restorative material are of utmost importance, since there towards the periodontal ligament and the alveolar bone; this exists a paradigm that this mechanical property allows the function is fundamental for the protection of the pulp. In restoration to work efficiently and for a long period. This this manner, the dental pulp does not receive any type of mechanical agent (load or stress) that could cause irritation conceptualization is not completely adequate. Ceramic mate- rials have a mechanical behavior with less predictability than or inflammation in it. metals [5]. In addition, ceramics are hard but fragile [6]. As already mentioned, it is imperative to consider the There are concepts that can be contradictory for some sectors nature and mechanical behavior of both dental tissues and of the general dental community. Nowadays, restorations restorative material, in this case, dental zirconium. The main factor to consider is the rigidity of the material, understand- made with zirconium (commonly called zirconia, dental zir- conium, dental zirconia, dental zirconia, or dental zirco- ing rigidity as the resistance of a material to undergo defor- nium) are currently in great use [7]. This material has mations; hence, it is granted in turn the property of being generated a considerable interest for its application in den- hard but fragile. By not having the ability to deform, the tistry, due to properties that are considered ideal. In various material fails, and the fracture ensues. The dentin is capable of solving the enamel’s rigidity and supports its inability to articles of dental journals, it is said that it is a highly aesthetic material with an acceptable lifespan (between three and five deform, preventing the enamel from failing or fracturing. In years) and with an average success rate of 94% [8–11]. this same way, the occlusal loads and stresses that the enamel In terms of physical-mechanical properties, zirconium backs receive are dissipated by the dentin to avoid reaching has great standout advantages such as high values of tough- the pulp tissue. When a restoration with dental zirconium is placed, this ness, great hardness, wear resistance, good frictional behav- ior, good electrical insulation, low thermal conductivity, material exceeds the hardness and rigidity of the dental tis- and resistance to corrosion (substances acids and alkaline), sues, in a dental organ with a history of caries; these remain- ing tissues have undergone an alteration in their properties, which makes it an ideal material [9]. It is also mentioned that it has a modulus of elasticity like steel and a coefficient of but not only chemical and biological but also mechanical, so the repercussions are greater. Dental zirconium is a very thermal expansion like iron [12]. Values are higher than those of the tooth enamel and dentin, so the hardness and hard and rigid material that is placed in the enamel and den- rigidity are greater than those of both dental tissues. tin; a tissue that has been stiffened and that has lost its sup- porting tissue, the dentin causes the loads and stresses to Although dental zirconium and dental tissues are materials of the same nature (hard and fragile) to have ranges so dis- increase and reach areas in which they should be present. Therefore, the dentin would be exceeded in its function of tant in the values of their mechanical properties (elasticity module mainly), their mechanical behavior also varies. Their solving the rigidity and the incapacity of the deformation. stress-strain graphs, although they behave similarly (rigid/- In this way, although the dental zirconium would not suffer faults, the remaining enamel would do so due to the differ- hard materials), cannot be identified as similar. The stress necessary to cause a deformation in the dental zirconium is ences between the mechanical behaviors of both materials. In addition, the dentin would not be able to protect the dental greater than those required for the enamel and even greater for the dentin [13]. pulp, causing it to receive loads and stresses that should not Several studies have established that the use of this mate- be present. The present work shows the reactions that occur in the rial causes the chipping of the coating ceramic, central frac- tures of the restored dental organ, and the abrasion and pulp tissue when a dental zirconium restoration is used, wear of the antagonist teeth [14]. On the other hand, it is also due to the differences in mechanical behavior described mentioned that, for its placement, it requires greater wear of above, which modify the symbiotic or synergic relationship the healthy remaining tissues of the organ to be restored and, between the dental tissues. This is done through linear- elastic numerical analysis by means of the application of the during the chewing process, the action of moisture in the oral cavity microfractures can occur. It is common to find that Finite Element Method, from which high-biofidelity biomo- patients with this kind of restorations tend to return for dels were used [23, 24]. consultation; this is because their restored tooth has been fractured or pain is present when chewing. In some cases, 2. Materials and Methods the opposing tooth to the restoration is the one that presents pain during the mastication or worst when fracture occurs To find reactions and stress fields that arise in dental tissues [15–22]. Another situation to consider is the one in which through numerical analysis, two study cases were considered: the extent of this material can alter the normal function of Case 1—a control case, with a healthy lower first molar, and dental tissues. In a healthy tooth, the masticatory forces act Case 2—a lower first molar with a history of second-degree on the enamel, the material of the tooth which is a hard but caries on the occlusal face. It was restored with an inlay of fragile tissue. These loads pass through the enamel and are dental zirconium. The biomodels corresponding to each case received by the dentin, which is a specialized connective tis- were generated from 3D imaging, by means of a Digital Applied Bionics and Biomechanics 3 Restoration Enamel Pulp Dentin (a) (b) (c) Figure 1: The molar: (a) three tissues, (b) healthy molar, and (b) molar dental zirconium restoration. Table 1: Mechanical properties used in the analysis. Volumetric Tomography (DVT) of the maxilla and mandible with the Computed Tomography System Cone Beam Young’s Poisson’s ratio (CTCB), to obtain DICOM files. With these files and using Dental tissue Density modulus dimensionless a methodology developed by the authors in previous works Enamel 70 GPa 0.30 0.25 g/cm [2, 25], these biomodels have high morphological and mor- Dentin 18.3 GPa 0.30 0.31 g/cm phometric biofidelity; three tissues are considered for the molar: enamel, dentin, and pulp and the dental restoration Pulp 2 GPa 0.45 0.1 g/cm (Figure 1). Dental zirconium 250 GPa 0.32 5.68 g/cm For the numerical analyses, the tissues and dental zirco- restoration nium of the biomodels are considered materials that present a linear, elastic, and continuous behavior, and their internal 3. Results structure is considered to be isotropic and homogeneous. The boundary conditions are established at the dental rear The results obtained for each case are shown in Tables 3–5 zone of the dental roots; the displacements and rotations in and Figures 2–13. the directions of the X, Y, and Z axes are restricted in this Figure 3 shows the normal stresses on the X axis, Figure 4 region. The properties of the materials for the simulation shows the normal stresses on the Y axis, Figure 5 shows the are presented in Table 1 [26–30]. normal stresses on the Z axis, and Figure 6 shows the von A load was applied in the form of pressure on the Mises stresses in enamel for both cases. occlusal area of the biomodels, to simulate the dental occlu- Figure 6 shows the normal stresses on the X axis, Figure 7 sion. The magnitude of the applied load is 150 N/mm shows the normal stresses on the Y axis, Figure 8 shows the which corresponds to the biting force that is established normal stresses on the Z axis, and Figure 9 shows the von between both molars, which is distributed locally on the Mises stresses in the dentin for both cases. application area in the form of a pressure. It is important Figure 10 shows the normal stresses on the X axis, to mention that the bite contact (dental occlusion) is being Figure 11 shows the normal stresses on the Y axis, Figure 12 simulated and analyzed, not the chewing process; that is shows the normal stresses on the Z axis, and Figure 13 shows why, only a single load that corresponds to this phenome- the von Mises stresses in the pulp for both cases. non is applied [31–34]. The contacts between the tissues Tables 3–5 show the results obtained from the numerical and the restoration were considered for the analysis per- simulations carried out. formed. The detailed methodology to obtain the biomodel, Table 3 shows that the nominal stresses generated by from the three-dimensional images of the tomography, to dental occlusion on the enamel are greater in the restored the boundary conditions and mesh refinement, among molar than the healthy molar. In the X axis, in the others, is the same with those used in the research and pub- healthy molar, the maximum stresses are 0.0025 Pa in ten- lications developed previously by the authors [2, 3, 23, 35] sion and in the restored molar they are -17 41 × 10 Pa (Table 2). (-17.41 MPa/-17,410,000.00 Pa) in compression. In the Y The strain, displacements, normal stresses, shear stress, axis, in the healthy molar, the maximum stresses are and von Mises stresses were analyzed during the application -0.0025 Pa and in the restored molar they are -26 63 × 10 of the pressure that simulates dental bite or occlusion. How- ever, for the purposes of this work, only the results obtained Pa (-26.63 MPa/-26,630,000.00 Pa) in compression for both cases. In the Z axis, in the healthy molar, the maximum for nominal and von Mises stresses are shown. It should be mentioned that von Mises stresses are not considered here a stresses are 0.0096 Pa in tension and in the restored molar failure criterion (which is mainly applicable to ductile mate- they are -47 90 × 10 Pa (-26.63 MPa/-26,630,000.00 Pa) in rials) but a unique nondirectional value that allows to have a compression. On the other hand, the stresses of von Mises global criterion on the load at each tooth point, since it is are greater in the restored molar (40 28 × 10 Pa) obtained from the deformation energy. Several authors use (40.28 MPa/40,280,000 Pa) in relation to the healthy molar it as a criterion to evaluate restorations [30, 36, 37]. that presents 0.0124 Pa. 4 Applied Bionics and Biomechanics Table 2: Some details of the models. Healthy molar Restored molar Mesh Tetrahedral solid elements Tetrahedral solid elements Meshing Semicontrolled Semicontrolled Mesh quality High-order quadratic elements High-order quadratic elements Nodes 129,005 363,380 Elements 74,907 246,254 Table 3: Comparison of the results obtained between both study cases in enamel. Case 1 (healthy molar) Case 2 (restored molar) Values Maximum Minimum Maximum Minimum 6 6 Normal stresses in X 0.0025 Pa -0.002525 Pa -17 41 × 10 Pa 8 56 × 10 Pa 6 6 Normal stresses in Y -0.0025 Pa 0.002453 Pa -26 63 × 10 Pa 5 60 × 10 Pa 6 6 Normal stresses in Z 0.0096 Pa -0.003641 Pa -47 90 × 10 Pa 6 07 × 10 Pa 6 6 von Mises stresses 0.0124 Pa 0.0003 Pa 40 28 × 10 Pa 0 08 × 10 Pa Table 4: Comparison of the results obtained between both study cases in the dentin. Case 1 (healthy molar) Case 2 (restored molar) Values Maximum Minimum Maximum Minimum 6 6 Normal stresses in X -0.0015 Pa 0.0013 Pa -8 16 × 10 Pa 3 69 × 10 Pa 6 6 Normal stresses in Y 0.0015 Pa -0.0012 Pa -6 33 × 10 Pa 4 19 × 10 Pa 6 6 Normal stresses in Z -0.0026 Pa 0.0025 Pa -28 90 × 10 Pa 3 00 × 10 Pa 6 6 von Mises stresses 0.0027 Pa 0.00002 Pa 27 65 × 10 Pa 0 53 × 10 Pa Table 5: Comparison of the results obtained between both study cases in the pulp. Case 1 (healthy molar) Case 2 (restored molar) Values Maximum Minimum Maximum Minimum 6 6 Normal stresses in X -0.0006 Pa 0.0004 Pa 4 69 × 10 pa -2 34 × 10 Pa 6 6 Normal stresses in Y -0.0007 Pa -0.0004 Pa 4 79 × 10 Pa -2 43 × 10 Pa 6 6 Normal stresses in Z -0.0004 Pa 0.000402 Pa 11 01 × 10 Pa -5 91 × 10 Pa 6 6 von Mises stresses 0.0007 Pa 0.000002 Pa 5 29 × 10 Pa 3 003 × 10 Pa Occlusal Cervical Occlusal Cervical Z X –17.41 –11.64 –5.86 –0.95 5.67 –0.0025 –0.0013 –0.0002 0.0008 0.0020 –14.52 –8.75 –2.98 2.79 8.56x10 (Pa) –0.0019 –0.0008 0.0003 0.0014 0.0025 (Pa) (a) (b) Figure 2: Enamel normal stresses on the X axis: (a) healthy molar and (b) molar with dental zirconium restoration. Applied Bionics and Biomechanics 5 Occlusal Cervical Occlusal Cervical Z X –26.53 –19.46 –12.30 –5.14 2.02 –0.0025 –0.0014 –0.0003 0.0007 0.0018 –23.05 –15.88 –8.72 –1.55 5.60x10 (Pa) –0.0020 –0.00089 0.0002 0.0013 0.0024 (Pa) (a) (b) Figure 3: Enamel normal stresses on the Y axis: (a) healthy molar and (b) molar with dental zirconium restoration. Occlusal Cervical Occlusal Cervical Z X –0.0036 –0.0006 0.0022 0.0052 0.0081 –47.97 –35.90 –23.91 –11.91 0.81 –41.90 –29.90 –17.91 –0.59 6.07x10 (Pa) –0.0021 0.0007 0.0037 0.006 6 0.0096 (Pa) (a) (b) Figure 4: Enamel normal stresses on the Z axis: (a) healthy molar and (b) molar with dental zirconium restoration. Occlusal Cervical Occlusal Cervical 1.99 8.96 17.91 26.86 35.81 0.0003 0.0027 0.0055 0.0083 0.0110 4.49 13.44 22.39 31.33 40.28x10 (Pa) 0.0013 0.0041 0.0069 0.0096 0.0124 (Pa) (a) (b) Figure 5: Enamel von Mises stresses: (a) healthy molar and (b) molar with dental zirconium restoration. Table 4 shows the same phenomenon described above, X axis, in the healthy molar, the maximum stresses are the nominal forces generated by dental occlusion on the den- -0.0015 Pa and in the restored molar they are -8 16 × 10 tin are greater in the restored molar than in the healthy molar Pa (-8.16 MPa/-8,160,000.00 Pa) both in compression. In but change the type of stress (tension or compression). In the the Y axis, in the healthy molar, the maximum stresses 6 Applied Bionics and Biomechanics Distal Vestibular Lingual Mesial Occlusal –0.0015 –0.0008 –0.0005 0.0004 0.0010 –0.0011 –0.0005 0.00008 0.0007 0.0013 (Pa) (a) Vestibular Mesial Distal Lingual Occlusal Z X –8.16 –5.53 –2.89 –2.58 2.37 –6.85 –4.21 –1.57 1.06 3.69 x10 (Pa) (b) Figure 6: Dentin normal stresses on the X axis: (a) healthy molar and (b) molar with dental zirconium restoration. Distal Vestibular Lingual Mesial Occlusal –0.0012 –0.0006 0.0002 0.0006 0.0012 –0.0009 –0.0003 0.0003 0.0009 0.0015 (Pa) (a) Distal Vestibular Lingual Mesial Occlusal –6.33 –3.99 –1.64 6.84 3.02 –5.16 –2.82 –0.48 1.85 4.19 x10 (Pa) (b) Figure 7: Dentin normal stresses on the Y axis: (a) healthy molar and (b) molar with dental zirconium restoration. Applied Bionics and Biomechanics 7 Distal Vestibular Lingual Mesial Occlusal –0.0026 –0.0014 –0.0003 0.0008 0.0020 –0.0020 –0.0009 0.00002 0.0014 0.0025 (Pa) (a) Distal Vestibular Lingual Mesial Oc Occlusal clusal YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY X X X X X X X X X X X X X Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z –28.90 –21.81 –14.72 –7.63 –5.42 –25.36 –18.27 –11.17 –4.08 3.00 x10 (Pa) (b) Figure 8: Dentin normal stresses on the Z axis: (a) healthy molar and (b) molar with dental zirconium restoration. are 0.0015 Pa in tension and in the restored molar they are and 11 01 × 10 Pa (11.01 MPa/11,010,000) on the Z axis, in -6 33 × 10 Pa (-6.33 MPa/-6,330,000.00 Pa) in compres- tension for the 3 axes. As for the von Mises stresses, the sion. In the Z axis, in the healthy molar, the maximum maximum values are 5 29 × 10 Pa (5.29 MPa/5,290,000 Pa). stresses are -0.0026 Pa and in the restored molar are Therefore, stresses are being present in a tissue where they -28 90 × 10 Pa (-28.90 MPa/-28.900,000.00 Pa) in com- should not be. pression for both cases. The same happens for the von Mises stresses, they are greater in the molar restored 4. Discussion (27 65 × 10 Pa) (28.90 MPa/28,900,000 Pa) in relation to the healthy molar that presents 0.0027 Pa. Dental tissues are highly specialized; dental enamel is a tissue Table 5 shows that the main hypothesis of the work is that must withstand masticatory forces, making it a very hard correct: While in the healthy molar, the stresses that are material. Within the human body, it certainly is the hardest presented are negligible (almost zero), and in the restored material produced by the organism, a hard material present- molar, there are stresses of considerable value. As shown in ing a high resistance to be penetrated or scratched making Figure 13, the healthy molar presents the maximum stresses the material to have little or none ductility at all with almost of -0.0006 Pa on the X axis, -0.0007 Pa on the Y axis, and no tolerance to deformation which makes it a fragile material. -0.0004 for the Z axis; all of them in compression are consis- A hard material is capable to withstand high loads with virtu- tent with the acting agent (occlusal load) in practically all of ally zero deformation. These means that if a high load is the pulp tissues. This is because the loads and stresses were applied to a hard material, it will have a high resistance to dissipated by the dentin. On the other hand, it is important support this load when a deformation is required; since this to mention that the critical areas where the maximum material does not have this property, then it suddenly fails, stresses are presented are due to the geometry of the tissue and a fracture is produced. that, due to its anatomy, generate stress concentrators. The In order to mitigate this situation, the tooth has a support von Mises stresses present a maximum of 0.0007 Pa. tissue that is not as hard as enamel, being more ductile and In contrast, the restored molar presents the maximum elastic; this tissue is the dentin. This tissue contains a greater stresses of 4 69 × 10 Pa (4.69 MPa/4,690,000 Pa) on the X amount of collagen, which gives it greater ductility and elas- axis, 4 79 × 10 Pa (4.97 MPa/4,970,000 Pa) on the Y axis, ticity. The dentin, although it is a hard tissue-like bone, is 8 Applied Bionics and Biomechanics Distal Vestibular Lingual Mesial Occlusal 0.00002 0.0006 0.0012 0.0018 0.0024 0.0003 0.0009 0.0015 0.0021 0.0027 (Pa) (a) Distal Vestibular Lingual Mesial Occlusal 0.53 6.14 12.29 18.43 24.58 3.07 9.21 15.36 21.50 27.65 x106 (Pa) (b) Figure 9: Dentin von Mises stresses: (a) healthy molar and (b) molar with dental zirconium restoration. Lingual Mesial Distal Vestibular Occlusal –0.0006 –0.0003 –0.0001 0.00008 0.00003 –0.0005 –0.0002 –0.00003 0.0002 0.0004 (Pa) (a) Lingual Distal Mesial Occlusal Vestibular –2.34 –1.81 –1.28 –0.75 –0.21 –2.08 –1.55 –1.01 –0.48 4.69 x10 (Pa) (b) Figure 10: Pulp normal stresses on the X axis: (a) healthy molar and (b) molar with dental zirconium restoration. Applied Bionics and Biomechanics 9 Occlusal Vestibular Lingual Mesial Distal Z X –0.0007 –0.0004 –0.0002 0.0004 0.0003 –0.0006 –0.0003 –0.00008 0.0001 0.0004 (Pa) (a) Distal Lingual Mesial Vestibular Occlusal Z X –2.43 –1.88 –1.33 –0.77 –0.22 –2.15 –1.60 –1.05 –0.50 4.79 x10 (Pa) (b) Figure 11: Pulp normal stresses on the Y axis: (a) healthy molar and (b) molar with dental zirconium restoration. able to withstand as much load as the enamel does, even if cally with the dental tissues, as they do so naturally between it is not the one that directly receives the total masticatory them. This is why the tensions generated in the dental organ loads; by working in synergy with enamel, it reduces its fra- with the restoration are greater. The dentin cannot meet the gility and helps to distribute the loads. As already men- demand of the material to cover its inability to deform which tioned, the enamel receives the loads and masticatory can cause faults in the remaining enamel and in the transmis- forces that are distributed throughout the occlusal surface, sion of stresses to the pulp tissue. which contacts the food at the time of chewing. The dentin In the analyses carried out in the present work, in Table 2, functions as a buffer tissue to deal with these mechanical it is possible to observe that the normal stresses in the three agents, mitigating the fragility of the enamel and redirect- axes and those of von Mises, generated in the molar that ing the forces and masticatory loads towards the periodon- has the restoration, are significantly increased in comparison tal ligament and the alveolar bone. In this way, the dentin to those of the healthy molar in the zones where the reactions fulfills the function of providing support to the enamel are presented. The major critical zones are located mainly in and at the same time protecting the enamel and mainly the zone of the amelodentinous junction and in the pulp the pulp. (Figures 2–9). In a general way, in the Control Case, the nor- At this point, it would be important to ask how appropri- mal stresses on the pulp are practically null (Figure 3). In ate it is to consider a material harder than enamel to replace it Case 2, they are much larger and more significant stresses and make dental restorations. Considering also that gener- (Figure 9), which indicate that the role of the dentin in pre- ally, when a restoration is required, it is because both the venting stresses reaching the pulp was nullified, because it enamel and dentin have been lost, which is a fundamental tis- has overcome its ability to support the rigidity or resistance sue for the proper functioning of the enamel itself. With this to deformation, which presents the restoration. This could loss, a greater stiffness of the remaining enamel has been be related to the structural integrity of the molar for each found in previous studies [3], so when restoring with dental case, as per the modified geometry in the restoration, but zirconium, this is not working symbiotically or synergisti- due to these results, this could be interpreted that this is 10 Applied Bionics and Biomechanics Lingual Mesial Distal Vestibular Occlusal Z X –0.0004 −0.0002 −0.00004 0.0001 0.0003 –0.0003 −0.0001 0.00004 0.0002 0.004 (Pa) (a) Vestibular Mesial Distal Lingual Occlusal Z X −5.91 −4.60 −3.28 −1.97 −6.58 −5.26 −3.95 −2.63 −1.31 −11.01 x10 (Pa) (b) Figure 12: Pulp normal stresses on the Z axis: (a) healthy molar and (b) molar with dental zirconium restoration. because the mechanical properties of the tissues that are not achieving the necessary cervical seal, and alterations in being replaced are not sufficiently similar. the occlusion could give rise to alterations in the temporo- Also, with these results, it is possible to prove numerically mandibular joint, periodontal or neuralgia. On the other that the dental zirconium is too rigid, to be considered one hand, if the wear is excessive, pulp damage and even necrosis and by itself, as a totally adequate material to replace lost could occur. In addition, these types of restorations provide dental tissues. These statements were also based on the clin- an aesthetic appearance. ical observation of the patients, where it is reported that the Based on this, ceramics seem to be a better restoration teeth that are antagonistic to the restorations are worn out option. They are aesthetically more like dental tissues. Man- by chewing, that the healthy remaining tissues that sur- ufacturers offer various options in terms of colors and han- round the restoration are fractured, and that there is pain dling, which can be used in different patients and have when chewing. greater biocompatibility. This has made aesthetics and bio- compatibility, characteristics that are the most desirable in restoration materials. That is why, dental zirconium restora- 5. Conclusions tion is considered an excellent restorative material. However, Since its origins in dentistry, metal restorations had been the based on the hypothesis established in this paper and the first option. However, the types of materials could not be results obtained, it is established that, although it is a good fully biocompatible and could compromise the integrity of option, there are still other parameters that should be consid- the biological and cellular systems. In addition to this, the ered. Therefore, it is possible to conclude the following: design of cavities and preparations to receive the restorations require a wear on the remaining healthy dental tissue [5]. If (1) The mechanical behavior of dental zirconium, in fact, differs from that of dental tissues, its rigidity being the wear is insufficient, the restoration can be dislodged, Applied Bionics and Biomechanics 11 Occlusal Vestibular Lingual Mesial Distal Z X 0.000002 0.0001 0.0003 0.00048 0.0006 0.00008 0.0002 0.00046 0.0005 0.0007 (Pa) (a) Occlusal Vestibular Lingual Mesial Distal 0.08 1.17 2.35 3.53 4.70 0.05 1.76 2.94 4.12 5.29 x10 (Pa) (b) Figure 13: Pulp von Mises stresses: (a) healthy molar and (b) molar with dental zirconium restoration. the main factor to consider. The enamel and dentin, In turn, they allow the performance of the normal being one more elastic than the other, allow to per- function of the surrounding tissues; above all these, form its masticatory function without causing any a synergistic or symbiotic function is carried out failure in any of the tissues, mainly the enamel, since such as that of the relationship between the enamel the dentin is able to withstand the hardness and and dentin rigidity of the enamel, in this way dissipating the (3) This does not mean that the dental zirconium should loads and stresses generated outside the pulp tissue. be eliminated as an option for restoration material. With the restoration of the dental zirconium, this However, it is necessary to carry out additional stud- function is altered and the ability of the dentin to ies and find under what cases it is well indicated or if withstand the rigidity is overcome it is necessary to use it together with other materials (2) So, in addition to seeking the aesthetics and biocom- to improve its functioning, that is, finding a material patibility of restorative materials, it is necessary to that solves its hardness and rigidity as does dentin find their biomechanical compatibility, understand- with enamel ing this concept as the property of a material to resemble the mechanical properties of the tissues to Data Availability be restored or replaced, in such a way that they imi- tate the functions of the lost tissue and allow their The data used to support the findings of this study are performance as nature designed them (mimicry). included within the article. 12 Applied Bionics and Biomechanics Conflicts of Interest [12] N. R. Sadaqah, “Ceramic laminate veneers: materials advances and selection,” Open Journal of Stomatology, vol. 4, no. 5, The authors declare that there is no conflict of interest pp. 268–279, 2014. regarding the publication of this paper. [13] K. J. Chun, H. H. Choi, and J. Y. Lee, “Comparison of mechan- ical property and role between enamel and dentin in the human teeth,” Journal of Dental Biomechanics, vol. 5, 2014. Acknowledgments [14] M. Øilo, A. D. Hardang, A. H. Ulsund, and N. R. Gjerdet, “Fractographic features of glass-ceramic and zirconia-based The authors gratefully acknowledge the Instituto Politécnico dental restorations fractured during clinical function,” Nacional and the Consejo Nacional de Ciencia y Tecnología. European Journal of Oral Sciences, vol. 122, no. 3, pp. 238– 244, 2014. [15] U. Somchai and T. Pakamard, “The effect of zirconia frame- References work design on the failure of all-ceramic crown under static loading,” The Journal of Advanced Prosthodontics, vol. 7, [1] O. Moncada and B. J. Herazo, “Estudio nacional de salud,” no. 2, pp. 146–150, 2015. Morbilidad Oral, Ministerio de Salud, vol. 1, no. 1, pp. 41–43, [16] J. Peláez- Rico, C. López-Suárez, V. Rodríguez-Alonso, and M. Juárez-Suárez, “Circonio en prótesis fija: casos clínicos,” [2] R. A. Hernández-Vázquez, Análisis mecanobiológico de la Gaceta Dental, vol. 279, no. 1, pp. 216–234, 2016. distribución de esfuerzos debido a cargas masticatorias, sobre [17] A. J. Raigrodski, G. J. Chiche, N. Potiket et al., “The efficacy of los órganos dentales, Doctoral Thesis, Instituto Politécnico posterior three-unit zirconium oxide based ceramic fixed par- Nacional, México, 2018. tial dental prostheses: a prospective clinical pilot study,” Jour- [3] R. A. Hernández-Vázquez, B. Romero-Ángeles, nal of Prosthetic Dentistry, vol. 96, no. 4, pp. 237–244, 2006. G. Urriolagoitia-Sosa, J. A. Vázquez-Feijoo, R. A. Marquet- [18] J. Schmitt, S. Holst, M. Wichmann, S. Reich, M. Göllner, and Rivera, and G. Urriolagoitia-Calderón, “Mechanobiological J. Hamel, “Zirconia posterior fixed partial dentures: a prospec- analysis of molar teeth with carious lesions through the tive clinical 3-year follow-up,” International Journal of Pros- finite element method,” Applied Bionics and Biomechanics, thodontics, vol. 22, no. 6, pp. 597–603, 2009. vol. 2018, Article ID 1815830, 13 pages, 2018. [19] F. P. Nothdurft, P. R. Rountree, and P. R. Pospiech, “Clinical [4] E. G. Castro-Aguilar, C. O. Matta-Morales, and O. Orellana- long-term behavior of zirconia-based bridges (LAVA): five Valdivieso, “Consideraciones actuales en la utilización de years results,” Journal of Dental Restoration, vol. 85, no. Spec coronas unitarias libres de metal en el sector posterior,” Iss C, article 0312, 2006. Revista Estomatológica Herediana, vol. 24, no. 4, pp. 278– [20] I. Sailer, A. Feher, F. Filser et al., “Prospective clinical study of 286, 2014. zirconia posterior fixed partial dentures: 3-year follow-up,” [5] C. P. Chaustre-Sánchez, I. H. García-Páez, and J. E. Barbosa- Quintessence International, vol. 37, no. 9, pp. 685–693, 2006. Jaimes, Análisis de weibull para la predicción de falla en restau- [21] D. delhoff, F. Beuer, V. Weber, and C. Johnen, “HIP zirconia raciones cerámicas de premolares humanos, Encuentro Inter- fixed partial dentures–clinical results after 3 years of clinical nacional de Educación Matemática, Cúcta, Colombia, 2016. service,” Quintessence International, vol. 39, no. 6, pp. 459– [6] A. Ramos, M. Muñiz-Calvente, P. Fernández, A. Fernández 471, 2008. Canteli, and M. J. Lamela, “Análisis probabilístico de elemen- [22] J. Pelaez, P. G. Cogolludo, B. Serrano, L. Lozano, F. José, and tos de vidrio recocido mediante una distribución triparamé- trica Weibull,” Boletín de la sociedad española de cerámica y M. J. Suárez, “A four-year prospective clinical evaluation of zirconia and metal-ceramic posterior fixed dental prostheses,” vidrio, vol. 54, no. 4, pp. 153–158, 2015. International Journal of Prosthodontics, vol. 25, no. 5, pp. 451– [7] S. Ali, S. Karthigeyan, M. Deivanai, and R. Mani, “Zirconia: 458, 2012. properties and application: a review,” Pakistan Oral & Dental Journal, vol. 34, no. 1, pp. 178–183, 2014. [23] R. A. Hernández-Vázquez, B. Romero-Ángeles, G. Urriolagoitia-Sosa, J. A. Vázquez-Feijoo, Á. J. Vázquez- [8] O. E. Pecho, R. Ghinea, A. M. Ionescu, J. C. Cardona, A. Della López, and G. Urriolagoitia-Calderón, “Numerical analysis of Bona, and M. . M. Pérez, “Optical behavior of dental zirconia masticatory forces on a lower first molar, considering the con- and dentin analyzed by Kubelka–Munk theory,” Dental Mate- tact between dental tissues,” Applied Bionics and Biomechan- rials, vol. 31, no. 1, pp. 60–67, 2015. ics, vol. 2018, Article ID 4196343, 15 pages, 2018. [9] A. del Rocío-González Ramírez, T. M. Virgilio-Virgilio, J. de la [24] R. A. Marquet-Rivera, G. Urriolagoitia-Sosa, R. A. Hernández- Fuente-Hernández, and R. García-Contreras, “Tiempo de vida Vázquez, B. Romero-Ángeles, J. A. Vázquez-Feijoo, and de las restauraciones dentales libres de metal: revisión sistemá- G. Urriolagoitia-Calderón, “Computational biomodelling and tica,” Revista ADM, vol. 73, no. 1, pp. 116–120, 2016. numerical analysis as means of diagnostic and odontological [10] N. T. Suárez-B, J. C. Escobar-Rstrepo, F. Latorre-Correa, and prognosis,” MOJ Applied Bionics and Biomechanics, vol. 2, J. Villarraga-Ossa, “Static behavior of a zirconia abutment sub- no. 4, pp. 262-263, 2018. jected to artificial aging. Finite element method,” Revista [25] R. A. Marquet-Rivera, G. Urriolagoitia-Sosa, R. A. Hernández- Facultad de Odontología Universidad de Antioquia, vol. 27, no. 1, pp. 30–62, 2015. Vázquez et al., “The importance of bio-fidelity in the model- ling for a biomechanical analysis,” MOJ Applied Bionics and [11] B. Beger, H. Goetz, M. Morlock, E. Schiegnitz, and B. Al-Nawas, Biomechanics, vol. 2, no. 3, pp. 174-175, 2018. “In vitro surface characteristics and impurity analysis of five different commercially available dental zirconia implants,” [26] S. Park, J. B. Quinn, E. Romberg, and D. Arola, “On the International Journal of Implant Dentistry, vol. 4, no. 1, brittleness of enamel and selected dental materials,” Dental pp. 1–10, 2018. Materials, vol. 24, no. 11, pp. 1477–1485, 2008. Applied Bionics and Biomechanics 13 [27] J. D. Carbajal, J. A. Villarraga, F. Latorre, and V. Restrepo, Análisis por el método de los elementos finitos sobre una prótesis parcial fija (ppf) de cinco elementos con unión rígida y no rígida, Congreso colombiano de métodos numéricos: Simulación en Ciencias y Aplicaciones Industriales, Colombia, [28] C. A. Rivera-Velásquez, H. Ossa, and D. Arola, “Fragilidad y comportamiento mecánico del esmalte dental,” Revista Inge- niería Biomédica, vol. 6, no. 12, pp. 10–16, 2012. [29] C. Márquez-Córdoba, J. C. Escobar-Restrepo, F. Latorre- Correa, and J. Villarraga-Ossa, “Distribución de los esfuer- zos en tramos protésicos fijos de cinco unidades con pilar intermedio: análisis biomecánico utilizando un modelo de elementos finitos,” Revista de la Facultad de Odontología de la Universidad de Antioquia, vol. 22, no. 2, pp. 153– 163, 2011. [30] A. Larios-Cervantes, A. Aguilera-Galaviz, C. Aceves, and C. Gaitan-Fonseca, “Diseño, fabricación y evaluación clínica de implantes trans-endodónticos de óxido de zirconio,” Revista Iberoamericana de Ciencias, vol. 3, no. 1, pp. 64–70, [31] É. A. Pineda-Duque, J. C. Escobar-Restrepo, F. Latorre-Correa, and J. A. Villarraga-Ossa, “Comparación de la resistencia de tres sistemas cerámicos en tramos protésicos fijos anteriores. Análisis por elementos finitos,” Revista de la Facultad de Odontología de la Universidad de Antioquia, vol. 25, no. 1, pp. 44–75, 2013. [32] O. Loyola-González, D. Torassa, and A. Dominguez, “Estudio comparativo sobre el comportamiento y la distribución de las tensiones en implantes dentales cortos e implantes dentales estándares en la región posterior del maxilar superior. Un estu- dio en elementos finitos,” Revista Clínica de Periodoncia, Implantología y Rehabilitación Oral, vol. 9, no. 1, pp. 36–41, [33] L. V. Velarde-Muñoz and R. Ángeles-Maslucán, “Análisis de tensiones compresivas en modelos de elementos finitos de dos prótesis fijas con pilar intermedio y diferentes conex- iones,” Revista Científica Odontológica, vol. 1, no. 1, pp. 35– 41, 2014. [34] B. Mellado-Alfaro, S. Anchelia-Ramirez, and E. Quea- Cahuana, “Resistencia a la compresión de carillas cerámicas de disilicato de litio cementadas con cemento resinoso dual y cemento resinoso dual autoadhesivo en premolares maxi- lares,” International Journal of Odontostomatology, vol. 9, no. 1, pp. 85–89, 2015. [35] C. I. López, L. A. Laguado, and L. E. Forero, “Evaluación mecá- nica sobre el efecto de cargas oclusales en la bonexión interfaz ósea, comparando 4 diseños de implantes para carga inme- diata en aleaciones ti6al4v y tinbzr (tiadynetm) por análisis en elementos finitos,” Suplemento de la Revista Latinoameri- cana de Metalurgia y Materiales, vol. S1, no. 1, pp. 47–54, 2009. [36] R. A. Hernández-Vázquez, G. Urriolagoitia-Sosa, R. A. Marquet-Rivera et al., “New scopes of computational biome- chanics in dentistry,” MOJ App Bionics and Biomechanics, vol. 2, no. 3, pp. 186-187, 2018. [37] J. A. Guerrero, D. C. Martínez, and L. M. Méndez, “Análisis biomecánico comparativo entre coronas individuales y restau- raciones ferulizadas implanto soportadas mediante el uso del método de los elementos finitos,” AVANCES Investigación en Ingeniería, vol. 8, no. 2, pp. 8–17, 2011. 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Hindawi Applied Bionics and Biomechanics Volume 2019, Article ID 1049306, 13 pages https://doi.org/10.1155/2019/1049306 Research Article Numerical Analysis of a Dental Zirconium Restoration and the Stresses That Occur in Dental Tissues Rosa Alicia Hernández-Vázquez , Guillermo Urriolagoitia-Sosa, Rodrigo Arturo Marquet-Rivera , Beatriz Romero-Ángeles, Octavio-Alejandro Mastache-Miranda , and G. Guillermo Urriolagoitia-Calderón Instituto Politécnico Nacional, Escuela Superior de Ingeniería Mecánica y Eléctrica, Sección de Estudios de Posgrado e Investigación, Unidad Profesional Adolfo López Mateos “Zacatenco, ” Avenida Instituto Politécnico Nacional, S/n Edificio 5, 2do. Piso, Col. Lindavista, C.P. 07320 Ciudad de México, Mexico Correspondence should be addressed to Rosa Alicia Hernández-Vázquez; alyzia.hv@esimez.mx Received 17 January 2019; Revised 25 June 2019; Accepted 13 August 2019; Published 5 September 2019 Academic Editor: Mohammad Rahimi-Gorji Copyright © 2019 Rosa Alicia Hernández-Vázquez et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. When it is about restorative dental materials, aesthetics is traditionally preferred. This has led to the selection of materials very visually similar to the enamel, but unfortunately, their mechanical properties are not similar. This often translates into disadvantages than advantages. In the present work, a comparison is made of the stresses that occur during dental occlusion (dental bit) in a healthy dental organ and those that are generated in a dental organ with a dental zirconium restoration. Numerical simulation was carried out by means of the Finite Element Method, in computational biomodels, from Cone-Beam Tomography, to obtain the stresses generated during dental occlusion. It was found that the normal and von Mises stresses generated are substantially greater in the molar with restoration compared to those produced in the healthy molar. In addition, the normal function of the enamel and dentin to disperse these stresses to prevent them from reaching the pulp is altered. Therefore, it is necessary to analyze the indiscriminate use of this restoration material and consider other aspects, in addition to aesthetics and biocompatibility for the choice of restorative materials such as biomechanical compatibility. 1. Introduction essary to consider the degree and location of the defect, the evolution time, the degree of aggressiveness, the amount of affected tissue, and the healthy tissue remaining. Today’s dentistry is focused on achieving its transformation, from being an area of therapeutic medicine to becoming a A fundamental aspect that should be considered is that preventive health area. However, it is still on track to achieve dental tissue affected by caries has undergone variations in that goal. The odontological task is mainly of restorative type. its biological, physical, chemical, and mechanical properties, This restorative nature of dentistry is due to the high inci- due to the caries process and mastication. There is evidence dence of caries and its consequences. It has been reported that, in dental tissues affected by caries, there is a stiffening that 95% of the world population suffers from or has suffered phenomenon of both the affected tissue and the healthy rem- tooth caries. The rate of caries recidivism or the restorative nant, which makes the tissues more fragile by mechanical treatment by itself is not a resolutive therapy [1]. Facing these means [2, 3]. This agrees with general dentistry knowledge aspects, the dentist must select the treatment and restorative that a dental organ with caries is more prone to fracture dur- material suitable for each patient. They should consider the ing chewing, than a healthy one. And fundamental aspects behavior of the tooth to rehabilitate and restore it considering should be considered for the selection of the type of restora- different variables, such as masticatory forces and the type of tion and restorative material to be applied. A little less than pathology that occurs. In the case of carious lesions, it is nec- 20 years ago, the use of various ceramic materials for the 2 Applied Bionics and Biomechanics sue with a greater amount of collagen than the enamel, so manufacture of dental restorations was implemented. These materials have properties with greater similarities to those it is more elastic. This tissue supports the enamel and com- of dental tissues in terms of strength, aesthetics, and biocom- pensates for its fragility preventing it from easily fracturing. In addition, the dentin is responsible for sending the loads patibility [4]. For the dental community, the hardness and resistance of and stress that are produced by the masticatory forces a restorative material are of utmost importance, since there towards the periodontal ligament and the alveolar bone; this exists a paradigm that this mechanical property allows the function is fundamental for the protection of the pulp. In restoration to work efficiently and for a long period. This this manner, the dental pulp does not receive any type of mechanical agent (load or stress) that could cause irritation conceptualization is not completely adequate. Ceramic mate- rials have a mechanical behavior with less predictability than or inflammation in it. metals [5]. In addition, ceramics are hard but fragile [6]. As already mentioned, it is imperative to consider the There are concepts that can be contradictory for some sectors nature and mechanical behavior of both dental tissues and of the general dental community. Nowadays, restorations restorative material, in this case, dental zirconium. The main factor to consider is the rigidity of the material, understand- made with zirconium (commonly called zirconia, dental zir- conium, dental zirconia, dental zirconia, or dental zirco- ing rigidity as the resistance of a material to undergo defor- nium) are currently in great use [7]. This material has mations; hence, it is granted in turn the property of being generated a considerable interest for its application in den- hard but fragile. By not having the ability to deform, the tistry, due to properties that are considered ideal. In various material fails, and the fracture ensues. The dentin is capable of solving the enamel’s rigidity and supports its inability to articles of dental journals, it is said that it is a highly aesthetic material with an acceptable lifespan (between three and five deform, preventing the enamel from failing or fracturing. In years) and with an average success rate of 94% [8–11]. this same way, the occlusal loads and stresses that the enamel In terms of physical-mechanical properties, zirconium backs receive are dissipated by the dentin to avoid reaching has great standout advantages such as high values of tough- the pulp tissue. When a restoration with dental zirconium is placed, this ness, great hardness, wear resistance, good frictional behav- ior, good electrical insulation, low thermal conductivity, material exceeds the hardness and rigidity of the dental tis- and resistance to corrosion (substances acids and alkaline), sues, in a dental organ with a history of caries; these remain- ing tissues have undergone an alteration in their properties, which makes it an ideal material [9]. It is also mentioned that it has a modulus of elasticity like steel and a coefficient of but not only chemical and biological but also mechanical, so the repercussions are greater. Dental zirconium is a very thermal expansion like iron [12]. Values are higher than those of the tooth enamel and dentin, so the hardness and hard and rigid material that is placed in the enamel and den- rigidity are greater than those of both dental tissues. tin; a tissue that has been stiffened and that has lost its sup- porting tissue, the dentin causes the loads and stresses to Although dental zirconium and dental tissues are materials of the same nature (hard and fragile) to have ranges so dis- increase and reach areas in which they should be present. Therefore, the dentin would be exceeded in its function of tant in the values of their mechanical properties (elasticity module mainly), their mechanical behavior also varies. Their solving the rigidity and the incapacity of the deformation. stress-strain graphs, although they behave similarly (rigid/- In this way, although the dental zirconium would not suffer faults, the remaining enamel would do so due to the differ- hard materials), cannot be identified as similar. The stress necessary to cause a deformation in the dental zirconium is ences between the mechanical behaviors of both materials. In addition, the dentin would not be able to protect the dental greater than those required for the enamel and even greater for the dentin [13]. pulp, causing it to receive loads and stresses that should not Several studies have established that the use of this mate- be present. The present work shows the reactions that occur in the rial causes the chipping of the coating ceramic, central frac- tures of the restored dental organ, and the abrasion and pulp tissue when a dental zirconium restoration is used, wear of the antagonist teeth [14]. On the other hand, it is also due to the differences in mechanical behavior described mentioned that, for its placement, it requires greater wear of above, which modify the symbiotic or synergic relationship the healthy remaining tissues of the organ to be restored and, between the dental tissues. This is done through linear- elastic numerical analysis by means of the application of the during the chewing process, the action of moisture in the oral cavity microfractures can occur. It is common to find that Finite Element Method, from which high-biofidelity biomo- patients with this kind of restorations tend to return for dels were used [23, 24]. consultation; this is because their restored tooth has been fractured or pain is present when chewing. In some cases, 2. Materials and Methods the opposing tooth to the restoration is the one that presents pain during the mastication or worst when fracture occurs To find reactions and stress fields that arise in dental tissues [15–22]. Another situation to consider is the one in which through numerical analysis, two study cases were considered: the extent of this material can alter the normal function of Case 1—a control case, with a healthy lower first molar, and dental tissues. In a healthy tooth, the masticatory forces act Case 2—a lower first molar with a history of second-degree on the enamel, the material of the tooth which is a hard but caries on the occlusal face. It was restored with an inlay of fragile tissue. These loads pass through the enamel and are dental zirconium. The biomodels corresponding to each case received by the dentin, which is a specialized connective tis- were generated from 3D imaging, by means of a Digital Applied Bionics and Biomechanics 3 Restoration Enamel Pulp Dentin (a) (b) (c) Figure 1: The molar: (a) three tissues, (b) healthy molar, and (b) molar dental zirconium restoration. Table 1: Mechanical properties used in the analysis. Volumetric Tomography (DVT) of the maxilla and mandible with the Computed Tomography System Cone Beam Young’s Poisson’s ratio (CTCB), to obtain DICOM files. With these files and using Dental tissue Density modulus dimensionless a methodology developed by the authors in previous works Enamel 70 GPa 0.30 0.25 g/cm [2, 25], these biomodels have high morphological and mor- Dentin 18.3 GPa 0.30 0.31 g/cm phometric biofidelity; three tissues are considered for the molar: enamel, dentin, and pulp and the dental restoration Pulp 2 GPa 0.45 0.1 g/cm (Figure 1). Dental zirconium 250 GPa 0.32 5.68 g/cm For the numerical analyses, the tissues and dental zirco- restoration nium of the biomodels are considered materials that present a linear, elastic, and continuous behavior, and their internal 3. Results structure is considered to be isotropic and homogeneous. The boundary conditions are established at the dental rear The results obtained for each case are shown in Tables 3–5 zone of the dental roots; the displacements and rotations in and Figures 2–13. the directions of the X, Y, and Z axes are restricted in this Figure 3 shows the normal stresses on the X axis, Figure 4 region. The properties of the materials for the simulation shows the normal stresses on the Y axis, Figure 5 shows the are presented in Table 1 [26–30]. normal stresses on the Z axis, and Figure 6 shows the von A load was applied in the form of pressure on the Mises stresses in enamel for both cases. occlusal area of the biomodels, to simulate the dental occlu- Figure 6 shows the normal stresses on the X axis, Figure 7 sion. The magnitude of the applied load is 150 N/mm shows the normal stresses on the Y axis, Figure 8 shows the which corresponds to the biting force that is established normal stresses on the Z axis, and Figure 9 shows the von between both molars, which is distributed locally on the Mises stresses in the dentin for both cases. application area in the form of a pressure. It is important Figure 10 shows the normal stresses on the X axis, to mention that the bite contact (dental occlusion) is being Figure 11 shows the normal stresses on the Y axis, Figure 12 simulated and analyzed, not the chewing process; that is shows the normal stresses on the Z axis, and Figure 13 shows why, only a single load that corresponds to this phenome- the von Mises stresses in the pulp for both cases. non is applied [31–34]. The contacts between the tissues Tables 3–5 show the results obtained from the numerical and the restoration were considered for the analysis per- simulations carried out. formed. The detailed methodology to obtain the biomodel, Table 3 shows that the nominal stresses generated by from the three-dimensional images of the tomography, to dental occlusion on the enamel are greater in the restored the boundary conditions and mesh refinement, among molar than the healthy molar. In the X axis, in the others, is the same with those used in the research and pub- healthy molar, the maximum stresses are 0.0025 Pa in ten- lications developed previously by the authors [2, 3, 23, 35] sion and in the restored molar they are -17 41 × 10 Pa (Table 2). (-17.41 MPa/-17,410,000.00 Pa) in compression. In the Y The strain, displacements, normal stresses, shear stress, axis, in the healthy molar, the maximum stresses are and von Mises stresses were analyzed during the application -0.0025 Pa and in the restored molar they are -26 63 × 10 of the pressure that simulates dental bite or occlusion. How- ever, for the purposes of this work, only the results obtained Pa (-26.63 MPa/-26,630,000.00 Pa) in compression for both cases. In the Z axis, in the healthy molar, the maximum for nominal and von Mises stresses are shown. It should be mentioned that von Mises stresses are not considered here a stresses are 0.0096 Pa in tension and in the restored molar failure criterion (which is mainly applicable to ductile mate- they are -47 90 × 10 Pa (-26.63 MPa/-26,630,000.00 Pa) in rials) but a unique nondirectional value that allows to have a compression. On the other hand, the stresses of von Mises global criterion on the load at each tooth point, since it is are greater in the restored molar (40 28 × 10 Pa) obtained from the deformation energy. Several authors use (40.28 MPa/40,280,000 Pa) in relation to the healthy molar it as a criterion to evaluate restorations [30, 36, 37]. that presents 0.0124 Pa. 4 Applied Bionics and Biomechanics Table 2: Some details of the models. Healthy molar Restored molar Mesh Tetrahedral solid elements Tetrahedral solid elements Meshing Semicontrolled Semicontrolled Mesh quality High-order quadratic elements High-order quadratic elements Nodes 129,005 363,380 Elements 74,907 246,254 Table 3: Comparison of the results obtained between both study cases in enamel. Case 1 (healthy molar) Case 2 (restored molar) Values Maximum Minimum Maximum Minimum 6 6 Normal stresses in X 0.0025 Pa -0.002525 Pa -17 41 × 10 Pa 8 56 × 10 Pa 6 6 Normal stresses in Y -0.0025 Pa 0.002453 Pa -26 63 × 10 Pa 5 60 × 10 Pa 6 6 Normal stresses in Z 0.0096 Pa -0.003641 Pa -47 90 × 10 Pa 6 07 × 10 Pa 6 6 von Mises stresses 0.0124 Pa 0.0003 Pa 40 28 × 10 Pa 0 08 × 10 Pa Table 4: Comparison of the results obtained between both study cases in the dentin. Case 1 (healthy molar) Case 2 (restored molar) Values Maximum Minimum Maximum Minimum 6 6 Normal stresses in X -0.0015 Pa 0.0013 Pa -8 16 × 10 Pa 3 69 × 10 Pa 6 6 Normal stresses in Y 0.0015 Pa -0.0012 Pa -6 33 × 10 Pa 4 19 × 10 Pa 6 6 Normal stresses in Z -0.0026 Pa 0.0025 Pa -28 90 × 10 Pa 3 00 × 10 Pa 6 6 von Mises stresses 0.0027 Pa 0.00002 Pa 27 65 × 10 Pa 0 53 × 10 Pa Table 5: Comparison of the results obtained between both study cases in the pulp. Case 1 (healthy molar) Case 2 (restored molar) Values Maximum Minimum Maximum Minimum 6 6 Normal stresses in X -0.0006 Pa 0.0004 Pa 4 69 × 10 pa -2 34 × 10 Pa 6 6 Normal stresses in Y -0.0007 Pa -0.0004 Pa 4 79 × 10 Pa -2 43 × 10 Pa 6 6 Normal stresses in Z -0.0004 Pa 0.000402 Pa 11 01 × 10 Pa -5 91 × 10 Pa 6 6 von Mises stresses 0.0007 Pa 0.000002 Pa 5 29 × 10 Pa 3 003 × 10 Pa Occlusal Cervical Occlusal Cervical Z X –17.41 –11.64 –5.86 –0.95 5.67 –0.0025 –0.0013 –0.0002 0.0008 0.0020 –14.52 –8.75 –2.98 2.79 8.56x10 (Pa) –0.0019 –0.0008 0.0003 0.0014 0.0025 (Pa) (a) (b) Figure 2: Enamel normal stresses on the X axis: (a) healthy molar and (b) molar with dental zirconium restoration. Applied Bionics and Biomechanics 5 Occlusal Cervical Occlusal Cervical Z X –26.53 –19.46 –12.30 –5.14 2.02 –0.0025 –0.0014 –0.0003 0.0007 0.0018 –23.05 –15.88 –8.72 –1.55 5.60x10 (Pa) –0.0020 –0.00089 0.0002 0.0013 0.0024 (Pa) (a) (b) Figure 3: Enamel normal stresses on the Y axis: (a) healthy molar and (b) molar with dental zirconium restoration. Occlusal Cervical Occlusal Cervical Z X –0.0036 –0.0006 0.0022 0.0052 0.0081 –47.97 –35.90 –23.91 –11.91 0.81 –41.90 –29.90 –17.91 –0.59 6.07x10 (Pa) –0.0021 0.0007 0.0037 0.006 6 0.0096 (Pa) (a) (b) Figure 4: Enamel normal stresses on the Z axis: (a) healthy molar and (b) molar with dental zirconium restoration. Occlusal Cervical Occlusal Cervical 1.99 8.96 17.91 26.86 35.81 0.0003 0.0027 0.0055 0.0083 0.0110 4.49 13.44 22.39 31.33 40.28x10 (Pa) 0.0013 0.0041 0.0069 0.0096 0.0124 (Pa) (a) (b) Figure 5: Enamel von Mises stresses: (a) healthy molar and (b) molar with dental zirconium restoration. Table 4 shows the same phenomenon described above, X axis, in the healthy molar, the maximum stresses are the nominal forces generated by dental occlusion on the den- -0.0015 Pa and in the restored molar they are -8 16 × 10 tin are greater in the restored molar than in the healthy molar Pa (-8.16 MPa/-8,160,000.00 Pa) both in compression. In but change the type of stress (tension or compression). In the the Y axis, in the healthy molar, the maximum stresses 6 Applied Bionics and Biomechanics Distal Vestibular Lingual Mesial Occlusal –0.0015 –0.0008 –0.0005 0.0004 0.0010 –0.0011 –0.0005 0.00008 0.0007 0.0013 (Pa) (a) Vestibular Mesial Distal Lingual Occlusal Z X –8.16 –5.53 –2.89 –2.58 2.37 –6.85 –4.21 –1.57 1.06 3.69 x10 (Pa) (b) Figure 6: Dentin normal stresses on the X axis: (a) healthy molar and (b) molar with dental zirconium restoration. Distal Vestibular Lingual Mesial Occlusal –0.0012 –0.0006 0.0002 0.0006 0.0012 –0.0009 –0.0003 0.0003 0.0009 0.0015 (Pa) (a) Distal Vestibular Lingual Mesial Occlusal –6.33 –3.99 –1.64 6.84 3.02 –5.16 –2.82 –0.48 1.85 4.19 x10 (Pa) (b) Figure 7: Dentin normal stresses on the Y axis: (a) healthy molar and (b) molar with dental zirconium restoration. Applied Bionics and Biomechanics 7 Distal Vestibular Lingual Mesial Occlusal –0.0026 –0.0014 –0.0003 0.0008 0.0020 –0.0020 –0.0009 0.00002 0.0014 0.0025 (Pa) (a) Distal Vestibular Lingual Mesial Oc Occlusal clusal YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY X X X X X X X X X X X X X Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z –28.90 –21.81 –14.72 –7.63 –5.42 –25.36 –18.27 –11.17 –4.08 3.00 x10 (Pa) (b) Figure 8: Dentin normal stresses on the Z axis: (a) healthy molar and (b) molar with dental zirconium restoration. are 0.0015 Pa in tension and in the restored molar they are and 11 01 × 10 Pa (11.01 MPa/11,010,000) on the Z axis, in -6 33 × 10 Pa (-6.33 MPa/-6,330,000.00 Pa) in compres- tension for the 3 axes. As for the von Mises stresses, the sion. In the Z axis, in the healthy molar, the maximum maximum values are 5 29 × 10 Pa (5.29 MPa/5,290,000 Pa). stresses are -0.0026 Pa and in the restored molar are Therefore, stresses are being present in a tissue where they -28 90 × 10 Pa (-28.90 MPa/-28.900,000.00 Pa) in com- should not be. pression for both cases. The same happens for the von Mises stresses, they are greater in the molar restored 4. Discussion (27 65 × 10 Pa) (28.90 MPa/28,900,000 Pa) in relation to the healthy molar that presents 0.0027 Pa. Dental tissues are highly specialized; dental enamel is a tissue Table 5 shows that the main hypothesis of the work is that must withstand masticatory forces, making it a very hard correct: While in the healthy molar, the stresses that are material. Within the human body, it certainly is the hardest presented are negligible (almost zero), and in the restored material produced by the organism, a hard material present- molar, there are stresses of considerable value. As shown in ing a high resistance to be penetrated or scratched making Figure 13, the healthy molar presents the maximum stresses the material to have little or none ductility at all with almost of -0.0006 Pa on the X axis, -0.0007 Pa on the Y axis, and no tolerance to deformation which makes it a fragile material. -0.0004 for the Z axis; all of them in compression are consis- A hard material is capable to withstand high loads with virtu- tent with the acting agent (occlusal load) in practically all of ally zero deformation. These means that if a high load is the pulp tissues. This is because the loads and stresses were applied to a hard material, it will have a high resistance to dissipated by the dentin. On the other hand, it is important support this load when a deformation is required; since this to mention that the critical areas where the maximum material does not have this property, then it suddenly fails, stresses are presented are due to the geometry of the tissue and a fracture is produced. that, due to its anatomy, generate stress concentrators. The In order to mitigate this situation, the tooth has a support von Mises stresses present a maximum of 0.0007 Pa. tissue that is not as hard as enamel, being more ductile and In contrast, the restored molar presents the maximum elastic; this tissue is the dentin. This tissue contains a greater stresses of 4 69 × 10 Pa (4.69 MPa/4,690,000 Pa) on the X amount of collagen, which gives it greater ductility and elas- axis, 4 79 × 10 Pa (4.97 MPa/4,970,000 Pa) on the Y axis, ticity. The dentin, although it is a hard tissue-like bone, is 8 Applied Bionics and Biomechanics Distal Vestibular Lingual Mesial Occlusal 0.00002 0.0006 0.0012 0.0018 0.0024 0.0003 0.0009 0.0015 0.0021 0.0027 (Pa) (a) Distal Vestibular Lingual Mesial Occlusal 0.53 6.14 12.29 18.43 24.58 3.07 9.21 15.36 21.50 27.65 x106 (Pa) (b) Figure 9: Dentin von Mises stresses: (a) healthy molar and (b) molar with dental zirconium restoration. Lingual Mesial Distal Vestibular Occlusal –0.0006 –0.0003 –0.0001 0.00008 0.00003 –0.0005 –0.0002 –0.00003 0.0002 0.0004 (Pa) (a) Lingual Distal Mesial Occlusal Vestibular –2.34 –1.81 –1.28 –0.75 –0.21 –2.08 –1.55 –1.01 –0.48 4.69 x10 (Pa) (b) Figure 10: Pulp normal stresses on the X axis: (a) healthy molar and (b) molar with dental zirconium restoration. Applied Bionics and Biomechanics 9 Occlusal Vestibular Lingual Mesial Distal Z X –0.0007 –0.0004 –0.0002 0.0004 0.0003 –0.0006 –0.0003 –0.00008 0.0001 0.0004 (Pa) (a) Distal Lingual Mesial Vestibular Occlusal Z X –2.43 –1.88 –1.33 –0.77 –0.22 –2.15 –1.60 –1.05 –0.50 4.79 x10 (Pa) (b) Figure 11: Pulp normal stresses on the Y axis: (a) healthy molar and (b) molar with dental zirconium restoration. able to withstand as much load as the enamel does, even if cally with the dental tissues, as they do so naturally between it is not the one that directly receives the total masticatory them. This is why the tensions generated in the dental organ loads; by working in synergy with enamel, it reduces its fra- with the restoration are greater. The dentin cannot meet the gility and helps to distribute the loads. As already men- demand of the material to cover its inability to deform which tioned, the enamel receives the loads and masticatory can cause faults in the remaining enamel and in the transmis- forces that are distributed throughout the occlusal surface, sion of stresses to the pulp tissue. which contacts the food at the time of chewing. The dentin In the analyses carried out in the present work, in Table 2, functions as a buffer tissue to deal with these mechanical it is possible to observe that the normal stresses in the three agents, mitigating the fragility of the enamel and redirect- axes and those of von Mises, generated in the molar that ing the forces and masticatory loads towards the periodon- has the restoration, are significantly increased in comparison tal ligament and the alveolar bone. In this way, the dentin to those of the healthy molar in the zones where the reactions fulfills the function of providing support to the enamel are presented. The major critical zones are located mainly in and at the same time protecting the enamel and mainly the zone of the amelodentinous junction and in the pulp the pulp. (Figures 2–9). In a general way, in the Control Case, the nor- At this point, it would be important to ask how appropri- mal stresses on the pulp are practically null (Figure 3). In ate it is to consider a material harder than enamel to replace it Case 2, they are much larger and more significant stresses and make dental restorations. Considering also that gener- (Figure 9), which indicate that the role of the dentin in pre- ally, when a restoration is required, it is because both the venting stresses reaching the pulp was nullified, because it enamel and dentin have been lost, which is a fundamental tis- has overcome its ability to support the rigidity or resistance sue for the proper functioning of the enamel itself. With this to deformation, which presents the restoration. This could loss, a greater stiffness of the remaining enamel has been be related to the structural integrity of the molar for each found in previous studies [3], so when restoring with dental case, as per the modified geometry in the restoration, but zirconium, this is not working symbiotically or synergisti- due to these results, this could be interpreted that this is 10 Applied Bionics and Biomechanics Lingual Mesial Distal Vestibular Occlusal Z X –0.0004 −0.0002 −0.00004 0.0001 0.0003 –0.0003 −0.0001 0.00004 0.0002 0.004 (Pa) (a) Vestibular Mesial Distal Lingual Occlusal Z X −5.91 −4.60 −3.28 −1.97 −6.58 −5.26 −3.95 −2.63 −1.31 −11.01 x10 (Pa) (b) Figure 12: Pulp normal stresses on the Z axis: (a) healthy molar and (b) molar with dental zirconium restoration. because the mechanical properties of the tissues that are not achieving the necessary cervical seal, and alterations in being replaced are not sufficiently similar. the occlusion could give rise to alterations in the temporo- Also, with these results, it is possible to prove numerically mandibular joint, periodontal or neuralgia. On the other that the dental zirconium is too rigid, to be considered one hand, if the wear is excessive, pulp damage and even necrosis and by itself, as a totally adequate material to replace lost could occur. In addition, these types of restorations provide dental tissues. These statements were also based on the clin- an aesthetic appearance. ical observation of the patients, where it is reported that the Based on this, ceramics seem to be a better restoration teeth that are antagonistic to the restorations are worn out option. They are aesthetically more like dental tissues. Man- by chewing, that the healthy remaining tissues that sur- ufacturers offer various options in terms of colors and han- round the restoration are fractured, and that there is pain dling, which can be used in different patients and have when chewing. greater biocompatibility. This has made aesthetics and bio- compatibility, characteristics that are the most desirable in restoration materials. That is why, dental zirconium restora- 5. Conclusions tion is considered an excellent restorative material. However, Since its origins in dentistry, metal restorations had been the based on the hypothesis established in this paper and the first option. However, the types of materials could not be results obtained, it is established that, although it is a good fully biocompatible and could compromise the integrity of option, there are still other parameters that should be consid- the biological and cellular systems. In addition to this, the ered. Therefore, it is possible to conclude the following: design of cavities and preparations to receive the restorations require a wear on the remaining healthy dental tissue [5]. If (1) The mechanical behavior of dental zirconium, in fact, differs from that of dental tissues, its rigidity being the wear is insufficient, the restoration can be dislodged, Applied Bionics and Biomechanics 11 Occlusal Vestibular Lingual Mesial Distal Z X 0.000002 0.0001 0.0003 0.00048 0.0006 0.00008 0.0002 0.00046 0.0005 0.0007 (Pa) (a) Occlusal Vestibular Lingual Mesial Distal 0.08 1.17 2.35 3.53 4.70 0.05 1.76 2.94 4.12 5.29 x10 (Pa) (b) Figure 13: Pulp von Mises stresses: (a) healthy molar and (b) molar with dental zirconium restoration. the main factor to consider. The enamel and dentin, In turn, they allow the performance of the normal being one more elastic than the other, allow to per- function of the surrounding tissues; above all these, form its masticatory function without causing any a synergistic or symbiotic function is carried out failure in any of the tissues, mainly the enamel, since such as that of the relationship between the enamel the dentin is able to withstand the hardness and and dentin rigidity of the enamel, in this way dissipating the (3) This does not mean that the dental zirconium should loads and stresses generated outside the pulp tissue. be eliminated as an option for restoration material. With the restoration of the dental zirconium, this However, it is necessary to carry out additional stud- function is altered and the ability of the dentin to ies and find under what cases it is well indicated or if withstand the rigidity is overcome it is necessary to use it together with other materials (2) So, in addition to seeking the aesthetics and biocom- to improve its functioning, that is, finding a material patibility of restorative materials, it is necessary to that solves its hardness and rigidity as does dentin find their biomechanical compatibility, understand- with enamel ing this concept as the property of a material to resemble the mechanical properties of the tissues to Data Availability be restored or replaced, in such a way that they imi- tate the functions of the lost tissue and allow their The data used to support the findings of this study are performance as nature designed them (mimicry). included within the article. 12 Applied Bionics and Biomechanics Conflicts of Interest [12] N. R. Sadaqah, “Ceramic laminate veneers: materials advances and selection,” Open Journal of Stomatology, vol. 4, no. 5, The authors declare that there is no conflict of interest pp. 268–279, 2014. regarding the publication of this paper. [13] K. J. Chun, H. H. Choi, and J. Y. Lee, “Comparison of mechan- ical property and role between enamel and dentin in the human teeth,” Journal of Dental Biomechanics, vol. 5, 2014. Acknowledgments [14] M. Øilo, A. D. Hardang, A. H. Ulsund, and N. R. Gjerdet, “Fractographic features of glass-ceramic and zirconia-based The authors gratefully acknowledge the Instituto Politécnico dental restorations fractured during clinical function,” Nacional and the Consejo Nacional de Ciencia y Tecnología. European Journal of Oral Sciences, vol. 122, no. 3, pp. 238– 244, 2014. [15] U. Somchai and T. Pakamard, “The effect of zirconia frame- References work design on the failure of all-ceramic crown under static loading,” The Journal of Advanced Prosthodontics, vol. 7, [1] O. Moncada and B. J. Herazo, “Estudio nacional de salud,” no. 2, pp. 146–150, 2015. Morbilidad Oral, Ministerio de Salud, vol. 1, no. 1, pp. 41–43, [16] J. Peláez- Rico, C. López-Suárez, V. Rodríguez-Alonso, and M. Juárez-Suárez, “Circonio en prótesis fija: casos clínicos,” [2] R. A. Hernández-Vázquez, Análisis mecanobiológico de la Gaceta Dental, vol. 279, no. 1, pp. 216–234, 2016. distribución de esfuerzos debido a cargas masticatorias, sobre [17] A. J. Raigrodski, G. J. Chiche, N. Potiket et al., “The efficacy of los órganos dentales, Doctoral Thesis, Instituto Politécnico posterior three-unit zirconium oxide based ceramic fixed par- Nacional, México, 2018. tial dental prostheses: a prospective clinical pilot study,” Jour- [3] R. A. Hernández-Vázquez, B. Romero-Ángeles, nal of Prosthetic Dentistry, vol. 96, no. 4, pp. 237–244, 2006. G. Urriolagoitia-Sosa, J. A. Vázquez-Feijoo, R. A. Marquet- [18] J. Schmitt, S. Holst, M. Wichmann, S. Reich, M. Göllner, and Rivera, and G. Urriolagoitia-Calderón, “Mechanobiological J. Hamel, “Zirconia posterior fixed partial dentures: a prospec- analysis of molar teeth with carious lesions through the tive clinical 3-year follow-up,” International Journal of Pros- finite element method,” Applied Bionics and Biomechanics, thodontics, vol. 22, no. 6, pp. 597–603, 2009. vol. 2018, Article ID 1815830, 13 pages, 2018. [19] F. P. Nothdurft, P. R. Rountree, and P. R. Pospiech, “Clinical [4] E. G. Castro-Aguilar, C. O. Matta-Morales, and O. Orellana- long-term behavior of zirconia-based bridges (LAVA): five Valdivieso, “Consideraciones actuales en la utilización de years results,” Journal of Dental Restoration, vol. 85, no. Spec coronas unitarias libres de metal en el sector posterior,” Iss C, article 0312, 2006. Revista Estomatológica Herediana, vol. 24, no. 4, pp. 278– [20] I. Sailer, A. Feher, F. Filser et al., “Prospective clinical study of 286, 2014. zirconia posterior fixed partial dentures: 3-year follow-up,” [5] C. P. Chaustre-Sánchez, I. H. García-Páez, and J. E. Barbosa- Quintessence International, vol. 37, no. 9, pp. 685–693, 2006. Jaimes, Análisis de weibull para la predicción de falla en restau- [21] D. delhoff, F. Beuer, V. Weber, and C. Johnen, “HIP zirconia raciones cerámicas de premolares humanos, Encuentro Inter- fixed partial dentures–clinical results after 3 years of clinical nacional de Educación Matemática, Cúcta, Colombia, 2016. service,” Quintessence International, vol. 39, no. 6, pp. 459– [6] A. Ramos, M. Muñiz-Calvente, P. Fernández, A. Fernández 471, 2008. Canteli, and M. J. Lamela, “Análisis probabilístico de elemen- [22] J. Pelaez, P. G. Cogolludo, B. Serrano, L. Lozano, F. José, and tos de vidrio recocido mediante una distribución triparamé- trica Weibull,” Boletín de la sociedad española de cerámica y M. J. Suárez, “A four-year prospective clinical evaluation of zirconia and metal-ceramic posterior fixed dental prostheses,” vidrio, vol. 54, no. 4, pp. 153–158, 2015. International Journal of Prosthodontics, vol. 25, no. 5, pp. 451– [7] S. Ali, S. Karthigeyan, M. Deivanai, and R. Mani, “Zirconia: 458, 2012. properties and application: a review,” Pakistan Oral & Dental Journal, vol. 34, no. 1, pp. 178–183, 2014. [23] R. A. Hernández-Vázquez, B. Romero-Ángeles, G. Urriolagoitia-Sosa, J. A. Vázquez-Feijoo, Á. J. Vázquez- [8] O. E. Pecho, R. Ghinea, A. M. Ionescu, J. C. Cardona, A. Della López, and G. Urriolagoitia-Calderón, “Numerical analysis of Bona, and M. . M. Pérez, “Optical behavior of dental zirconia masticatory forces on a lower first molar, considering the con- and dentin analyzed by Kubelka–Munk theory,” Dental Mate- tact between dental tissues,” Applied Bionics and Biomechan- rials, vol. 31, no. 1, pp. 60–67, 2015. ics, vol. 2018, Article ID 4196343, 15 pages, 2018. [9] A. del Rocío-González Ramírez, T. M. Virgilio-Virgilio, J. de la [24] R. A. Marquet-Rivera, G. Urriolagoitia-Sosa, R. A. Hernández- Fuente-Hernández, and R. García-Contreras, “Tiempo de vida Vázquez, B. Romero-Ángeles, J. A. Vázquez-Feijoo, and de las restauraciones dentales libres de metal: revisión sistemá- G. Urriolagoitia-Calderón, “Computational biomodelling and tica,” Revista ADM, vol. 73, no. 1, pp. 116–120, 2016. numerical analysis as means of diagnostic and odontological [10] N. T. Suárez-B, J. C. Escobar-Rstrepo, F. Latorre-Correa, and prognosis,” MOJ Applied Bionics and Biomechanics, vol. 2, J. Villarraga-Ossa, “Static behavior of a zirconia abutment sub- no. 4, pp. 262-263, 2018. jected to artificial aging. Finite element method,” Revista [25] R. A. Marquet-Rivera, G. Urriolagoitia-Sosa, R. A. Hernández- Facultad de Odontología Universidad de Antioquia, vol. 27, no. 1, pp. 30–62, 2015. Vázquez et al., “The importance of bio-fidelity in the model- ling for a biomechanical analysis,” MOJ Applied Bionics and [11] B. Beger, H. Goetz, M. Morlock, E. Schiegnitz, and B. Al-Nawas, Biomechanics, vol. 2, no. 3, pp. 174-175, 2018. “In vitro surface characteristics and impurity analysis of five different commercially available dental zirconia implants,” [26] S. Park, J. B. Quinn, E. Romberg, and D. Arola, “On the International Journal of Implant Dentistry, vol. 4, no. 1, brittleness of enamel and selected dental materials,” Dental pp. 1–10, 2018. Materials, vol. 24, no. 11, pp. 1477–1485, 2008. Applied Bionics and Biomechanics 13 [27] J. D. Carbajal, J. A. Villarraga, F. Latorre, and V. Restrepo, Análisis por el método de los elementos finitos sobre una prótesis parcial fija (ppf) de cinco elementos con unión rígida y no rígida, Congreso colombiano de métodos numéricos: Simulación en Ciencias y Aplicaciones Industriales, Colombia, [28] C. A. Rivera-Velásquez, H. Ossa, and D. Arola, “Fragilidad y comportamiento mecánico del esmalte dental,” Revista Inge- niería Biomédica, vol. 6, no. 12, pp. 10–16, 2012. [29] C. Márquez-Córdoba, J. C. Escobar-Restrepo, F. Latorre- Correa, and J. Villarraga-Ossa, “Distribución de los esfuer- zos en tramos protésicos fijos de cinco unidades con pilar intermedio: análisis biomecánico utilizando un modelo de elementos finitos,” Revista de la Facultad de Odontología de la Universidad de Antioquia, vol. 22, no. 2, pp. 153– 163, 2011. [30] A. Larios-Cervantes, A. Aguilera-Galaviz, C. Aceves, and C. Gaitan-Fonseca, “Diseño, fabricación y evaluación clínica de implantes trans-endodónticos de óxido de zirconio,” Revista Iberoamericana de Ciencias, vol. 3, no. 1, pp. 64–70, [31] É. A. Pineda-Duque, J. C. Escobar-Restrepo, F. Latorre-Correa, and J. A. Villarraga-Ossa, “Comparación de la resistencia de tres sistemas cerámicos en tramos protésicos fijos anteriores. Análisis por elementos finitos,” Revista de la Facultad de Odontología de la Universidad de Antioquia, vol. 25, no. 1, pp. 44–75, 2013. [32] O. Loyola-González, D. Torassa, and A. Dominguez, “Estudio comparativo sobre el comportamiento y la distribución de las tensiones en implantes dentales cortos e implantes dentales estándares en la región posterior del maxilar superior. Un estu- dio en elementos finitos,” Revista Clínica de Periodoncia, Implantología y Rehabilitación Oral, vol. 9, no. 1, pp. 36–41, [33] L. V. Velarde-Muñoz and R. Ángeles-Maslucán, “Análisis de tensiones compresivas en modelos de elementos finitos de dos prótesis fijas con pilar intermedio y diferentes conex- iones,” Revista Científica Odontológica, vol. 1, no. 1, pp. 35– 41, 2014. [34] B. Mellado-Alfaro, S. Anchelia-Ramirez, and E. Quea- Cahuana, “Resistencia a la compresión de carillas cerámicas de disilicato de litio cementadas con cemento resinoso dual y cemento resinoso dual autoadhesivo en premolares maxi- lares,” International Journal of Odontostomatology, vol. 9, no. 1, pp. 85–89, 2015. [35] C. I. López, L. A. Laguado, and L. E. Forero, “Evaluación mecá- nica sobre el efecto de cargas oclusales en la bonexión interfaz ósea, comparando 4 diseños de implantes para carga inme- diata en aleaciones ti6al4v y tinbzr (tiadynetm) por análisis en elementos finitos,” Suplemento de la Revista Latinoameri- cana de Metalurgia y Materiales, vol. S1, no. 1, pp. 47–54, 2009. [36] R. A. Hernández-Vázquez, G. Urriolagoitia-Sosa, R. A. Marquet-Rivera et al., “New scopes of computational biome- chanics in dentistry,” MOJ App Bionics and Biomechanics, vol. 2, no. 3, pp. 186-187, 2018. [37] J. A. Guerrero, D. C. Martínez, and L. M. Méndez, “Análisis biomecánico comparativo entre coronas individuales y restau- raciones ferulizadas implanto soportadas mediante el uso del método de los elementos finitos,” AVANCES Investigación en Ingeniería, vol. 8, no. 2, pp. 8–17, 2011. 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Applied Bionics and BiomechanicsHindawi Publishing Corporation

Published: Sep 5, 2019

References