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Morphological Variations of the Cemento-Enamel Junction in Permanent Dentition / Morfološke varijacije cementno gleđnog spoja kod zuba stalne denticije

Morphological Variations of the Cemento-Enamel Junction in Permanent Dentition / Morfološke... ACTA FACULTATIS MEDICAE NAISSENSIS DOI: 10.1515/afmnai-2015-0021 UDC: 616.314 Morphological Variations of the Cemento-Enamel Junction in Permanent Dentition Nenad Stosi1, Stefan Daci2, Dragica Daci Simonovi2 University of Nis, Faculty of Medicine, Nis, Serbia Department of Restorative Dentistry and Endodontics, Clinic of Dentistry, Nis, Serbia SUMMARY Cemento-enamel junction (CEJ) is an important anatomical structure of the tooth, which is located in the cervical part of the tooth between the crown and root, or at the contact point between the enamel which overlaps the tooth crown and cementum overlapping the root dentin. There are four possible relationships between two tissues that make the CEJ such as: the cement overlaps the enamel; the enamel overlaps the cement; the enamel and cement abut each other with no overlap; the enamel and cement are not in contact. The aim of this study was to determine the relationship between the enamel and cement which make the CEJ in different types of permanent teeth. The material consisted of 30 permanent teeth with intact CEJ. Staining of CEJ was carried out using the methylene blue. After staining, the tooth was washed under the running water and drying at room temperature. Each tooth was longitudinally cut in the vestibular-oral direction. Observation of CEJ was done with Leica light microscope and images were obtained using a Nikon camera. The results indicated that the most common form of CEJ between the cement and enamel in the region of CEJ was that cement and enamel abutted without overlap (36.7%), followed by the cement overlapping the enamel (33.3%), and the cases when a gap between the cement and enamel (16.7%) was present, and when the enamel overlaped the cement (13.3%). Because of the morphological diversity of CEJ, careful performing of dental interventions in the region of tooth neck is necessary because they may change the morphology of this region, induce the pathological processes and hypersensitivity of teeth. Key words: cemento-enamel junction, cement, enamel Corresponding author: Nenad Stosi e-mail: nenadstosic10@gmail.com INTRODUCTION Cemento-enamel junction (CEJ) is an important anatomical and morphological structure of the tooth. It is located in the cervical part of the tooth between the crown and root, or at the contact point between the enamel which overlaps the tooth crown and cementum overlapping the root dentin (1,2). Gingival fibers are annexed to the CEJ and thus contribute to the stability of the tooth; therefore, examining CEJ is a useful clinical parameter for determining periodontal disease (2,3). In young individuals, CEJ is covered with the gingiva and thus is protected from various agents. The aging process, as well as the effects of various physical and chemical agents, may cause the withdrawal of the gingiva and the appearance of lesions in the area of CEJ. Disturbance of the integrity in the cement or enamel may expose dentin around the tooth neck and cause hypersensitivity, caries or erosion (2,4). The relationship between the cementum and enamel in the neck of the tooth varies. Connections between these two tissues that make up for mineralized CEJ can be bonded in four ways: 1. The cement overlaps the enamel, 2. The enamel overlaps the cement 3. The enamel and cement abut each other with no overlap. 4. The enamel and cement are not in contact (5). From the clinical point of view, the most favourable relationship in the CEJ is when the enamel overlaps the cement, as then the activity of acids and enzymes from the gingival biofilm have the least detrimental effect on the cervical region of the tooth. Furthermore, probing of the CEJ may have substantial clinical importance even in younger patients for the teeth whitening procedures, frequent caries and erosions of the tooth neck. Nis, Serbia. The study sample was comprised of 60 dissected parts of permanent teeth (30 crowns and 30 roots) from adult patients of both sexes, aged 18-65 years. The sample consisted of teeth from the upper and lower jaws (incisors, canines, premolars, molars) with the intact cement-enamel border. Teeth were extracted either for medical, orthodontic or prosthetics reasons. We applied the following procedure for the preparation of the tooth: each extracted tooth from the upper and lower jaw was carefully cleaned off residues of biological tissue, using a handpiece and steel drill, with adequate polishing abrasive discs, a rubber band, and abrasive paste. Before staining, the surface of each tooth was coated with two layers of clearcoat, which was applied both on the crown and on the root of the teeth, except in the region of 1 to 1.5 mm around CEJ. Further,we immersed the teeth into a container filled with 10% formalin, to facilitate staining and afterwards the teeth were left 24 hours to dry out. Next we immersed them in a 1% solution of methylene blue for 24h and lastly, after the staining was carried out, the teeth were washed under the running water for 1 minute and left to dry out for 12 to 24h. Each tooth was longitudinally dissected across the vestibular-palatal (lingual) plane in order to produce two samples with similar size. Cutting was done using a diamond disc mounted on a handpiece with water cooling. Examination of the CEJ was performed using a light microscope Leica, while the magnification and photographing were performed using a Nikon camera with a blue filter. RESULTS From a sample total of 60 dissected parts of teeth, the following results were obtained. The most common relationship between the cement and enamel in the region of CEJ was that cement and enamel were abutting without overlap (36.7%), followed by the cement overlapping the enamel (33.3%). The least observed cases of CEJ were visible when a gap between the cement and enamel (16.7%) was present, and when the enamel overlaped the cement (13.3%). The light microscopic images of four types of the cement-enamel junction are shown in Figures 1-4. AIMS The aim of this study was to determine the interrelationship of these two mineralized tissues that make the CEJ in different types of permanent teeth. MATERIALS AND METHODS The research was conducted in the period from February to March 2015, at the Department of Dentistry at the Faculty of Medicine, University of Nenad Stosi, Stefan Daci, Dragica Daci Simonovi C E E C Figure 1. Light microscopy finding of morphological variations of the cemento-enamel junction (CEJ) when the cement overlaps the enamel E ­ enamel, C- cement, D - dentin Figure 3. Light microscopy finding of morphological variations of the cemento-enamel junction (CEJ) when the cement and enamel abut each other E ­ enamel, C- cement, D - dentin E C E DK Figure 2. Light microscopy finding of morphological variations of the cemento-enamel junction (CEJ) when the enamel overlaps the cement E ­ enamel, C- cement, D - dentin Figure 4. Light microscopy findings of morphological variations of the cemento-enamel junction (CEJ) showing a distance between the two mineralized tissues with initial caries - denuded dentin-a gap. E ­ enamel, C- cement, DC ­ dentine caries I ­ Cement overlaps enamel II - Enamel overlaps cement III -Cement and enamel abut each other with no overlap IV -Gap between cement and enamel We analyzed the distribution of the mutual relationships between the cement and enamel including all dissections of teeth regardless of gender, tooth type and age of the patient. The most common relationship was that cement and enamel abutted each other with no overlap, no significant differences were observed as The distribution of the four types of mineralized dental tissues in the region of CEJ is provided in Table 1. Table1. Distribution of the relationship between mineralized tissues at the cemento-enamel junction in the total sample (n=60) Type of CEJ I II III IV n=60 20 8 22 10 % 33.3% 13.3% 36.7% 16.7% compared to the situation when the cement overlapped the enamel. In contrast, the mentioned cases of CEJ were significantly more distributed than the other two types, i.e. when there was a gap between the cement and the enamel and when the enamel overlapped the cement. individual (11,12). The neck region of the tooth was mostly investigated for cervical and radicular caries, increased sensitivity of the teeth and the frequent occurrence of cervical erosion (13,14). Young people are increasingly using refreshing drinks which contain acidic and erosive components. In the case of the unfavorable relationship of the cement and enamel, the exposed dentin is a subject to demineralization and erosion. Furthermore, in addition to diverse chemical and physical factors present in the oral environment, improper brushing of teeth may disturb the morphology of CEJ causing the exposure of dentin (2). The ratio of cement and enamel varies, not only between individuals but also between the types of teeth from the same person, even in different sections of the same tooth. Our sample consisted of teeth extracted from females and males of various ages and from both jaws, as one previous study already showed that age of patients, as well as the jaw of extracted tooth, do not significantly influence the results (2). The findings of this study showed a substantial proportion (16.7%) of cases when the exposed dentine was present in the region of the neck of the tooth. Therefore, we recommend that certain clinical procedures, such as the placement of hooks and metal prosthetics covers, removal of stones and concrements, and particularly whitening of teeth, should be carefully performed. DISCUSSION Cement-enamel border has been studied using a variety of methods such as microscopy (2), scanning electron microscopy (6), morphogens and embryonicanalysis (7,8). Since Choquet (9) in 1899 first described the four mutual relationships between the cement and enamel in CEJ region, all of these methods were used for the classification,which includes the following relationships: 1. The cement overlaps the enamel, 2. The enamel overlaps the cement, 3. The enamel and cement abut each other with no overlap, and 4. There is a space between the enamel and cement, with exposed dentin in-between. In our study, using the light microscopy, we confirmed the existence of all relationships between the cement and enamel as described by Choquet (9). However, some researchers were unable to find the relationship when the enamel overlaps the cement (10). Roa et al. (5) reported the four relationships between the cement and enamel that was described by Choquet in a sample of 68 teeth (9). In their findings, 51.9% of the cases described the relationship when the cement and enamel were in contact, whereas 42.4% of the cases showed that the enamel overlapped the cement. Our findings also showed that the two most common relationships between the cement and enamel were when the cement and enamel were in contact (36.7%), and when the cement overlapped the enamel (33.3%). We determined that the presence of the relationship when the enamel overlapped the cement accounted for 13.3%, which was similar to the distribution of cases when the enamel and cement were not in contact (16.7%). In the latter case, we observed the exposed dentin, demineralization, cervical and root caries. The importance of CEJ in periodontics and restorative odontology is increasing with aging of an CONCLUSION This study showed that the cement-enamel border is an important anatomical structure of the tooth with different morphological variations.Therefore, it has substantial importance for the proper implementation of certain dental procedures that take place in the region of the neck of the tooth and for the appropriate brushing of teeth. Otherwise, the morphology of CEJ may be violated, with the occurrence of increased tooth sensitivity to physical and chemical agents as well as to the development of pathological processes in the neck of the tooth. Nenad Stosi, Stefan Daci, Dragica Daci Simonovi http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Acta Facultatis Medicae Naissensis de Gruyter

Morphological Variations of the Cemento-Enamel Junction in Permanent Dentition / Morfološke varijacije cementno gleđnog spoja kod zuba stalne denticije

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Abstract

ACTA FACULTATIS MEDICAE NAISSENSIS DOI: 10.1515/afmnai-2015-0021 UDC: 616.314 Morphological Variations of the Cemento-Enamel Junction in Permanent Dentition Nenad Stosi1, Stefan Daci2, Dragica Daci Simonovi2 University of Nis, Faculty of Medicine, Nis, Serbia Department of Restorative Dentistry and Endodontics, Clinic of Dentistry, Nis, Serbia SUMMARY Cemento-enamel junction (CEJ) is an important anatomical structure of the tooth, which is located in the cervical part of the tooth between the crown and root, or at the contact point between the enamel which overlaps the tooth crown and cementum overlapping the root dentin. There are four possible relationships between two tissues that make the CEJ such as: the cement overlaps the enamel; the enamel overlaps the cement; the enamel and cement abut each other with no overlap; the enamel and cement are not in contact. The aim of this study was to determine the relationship between the enamel and cement which make the CEJ in different types of permanent teeth. The material consisted of 30 permanent teeth with intact CEJ. Staining of CEJ was carried out using the methylene blue. After staining, the tooth was washed under the running water and drying at room temperature. Each tooth was longitudinally cut in the vestibular-oral direction. Observation of CEJ was done with Leica light microscope and images were obtained using a Nikon camera. The results indicated that the most common form of CEJ between the cement and enamel in the region of CEJ was that cement and enamel abutted without overlap (36.7%), followed by the cement overlapping the enamel (33.3%), and the cases when a gap between the cement and enamel (16.7%) was present, and when the enamel overlaped the cement (13.3%). Because of the morphological diversity of CEJ, careful performing of dental interventions in the region of tooth neck is necessary because they may change the morphology of this region, induce the pathological processes and hypersensitivity of teeth. Key words: cemento-enamel junction, cement, enamel Corresponding author: Nenad Stosi e-mail: nenadstosic10@gmail.com INTRODUCTION Cemento-enamel junction (CEJ) is an important anatomical and morphological structure of the tooth. It is located in the cervical part of the tooth between the crown and root, or at the contact point between the enamel which overlaps the tooth crown and cementum overlapping the root dentin (1,2). Gingival fibers are annexed to the CEJ and thus contribute to the stability of the tooth; therefore, examining CEJ is a useful clinical parameter for determining periodontal disease (2,3). In young individuals, CEJ is covered with the gingiva and thus is protected from various agents. The aging process, as well as the effects of various physical and chemical agents, may cause the withdrawal of the gingiva and the appearance of lesions in the area of CEJ. Disturbance of the integrity in the cement or enamel may expose dentin around the tooth neck and cause hypersensitivity, caries or erosion (2,4). The relationship between the cementum and enamel in the neck of the tooth varies. Connections between these two tissues that make up for mineralized CEJ can be bonded in four ways: 1. The cement overlaps the enamel, 2. The enamel overlaps the cement 3. The enamel and cement abut each other with no overlap. 4. The enamel and cement are not in contact (5). From the clinical point of view, the most favourable relationship in the CEJ is when the enamel overlaps the cement, as then the activity of acids and enzymes from the gingival biofilm have the least detrimental effect on the cervical region of the tooth. Furthermore, probing of the CEJ may have substantial clinical importance even in younger patients for the teeth whitening procedures, frequent caries and erosions of the tooth neck. Nis, Serbia. The study sample was comprised of 60 dissected parts of permanent teeth (30 crowns and 30 roots) from adult patients of both sexes, aged 18-65 years. The sample consisted of teeth from the upper and lower jaws (incisors, canines, premolars, molars) with the intact cement-enamel border. Teeth were extracted either for medical, orthodontic or prosthetics reasons. We applied the following procedure for the preparation of the tooth: each extracted tooth from the upper and lower jaw was carefully cleaned off residues of biological tissue, using a handpiece and steel drill, with adequate polishing abrasive discs, a rubber band, and abrasive paste. Before staining, the surface of each tooth was coated with two layers of clearcoat, which was applied both on the crown and on the root of the teeth, except in the region of 1 to 1.5 mm around CEJ. Further,we immersed the teeth into a container filled with 10% formalin, to facilitate staining and afterwards the teeth were left 24 hours to dry out. Next we immersed them in a 1% solution of methylene blue for 24h and lastly, after the staining was carried out, the teeth were washed under the running water for 1 minute and left to dry out for 12 to 24h. Each tooth was longitudinally dissected across the vestibular-palatal (lingual) plane in order to produce two samples with similar size. Cutting was done using a diamond disc mounted on a handpiece with water cooling. Examination of the CEJ was performed using a light microscope Leica, while the magnification and photographing were performed using a Nikon camera with a blue filter. RESULTS From a sample total of 60 dissected parts of teeth, the following results were obtained. The most common relationship between the cement and enamel in the region of CEJ was that cement and enamel were abutting without overlap (36.7%), followed by the cement overlapping the enamel (33.3%). The least observed cases of CEJ were visible when a gap between the cement and enamel (16.7%) was present, and when the enamel overlaped the cement (13.3%). The light microscopic images of four types of the cement-enamel junction are shown in Figures 1-4. AIMS The aim of this study was to determine the interrelationship of these two mineralized tissues that make the CEJ in different types of permanent teeth. MATERIALS AND METHODS The research was conducted in the period from February to March 2015, at the Department of Dentistry at the Faculty of Medicine, University of Nenad Stosi, Stefan Daci, Dragica Daci Simonovi C E E C Figure 1. Light microscopy finding of morphological variations of the cemento-enamel junction (CEJ) when the cement overlaps the enamel E ­ enamel, C- cement, D - dentin Figure 3. Light microscopy finding of morphological variations of the cemento-enamel junction (CEJ) when the cement and enamel abut each other E ­ enamel, C- cement, D - dentin E C E DK Figure 2. Light microscopy finding of morphological variations of the cemento-enamel junction (CEJ) when the enamel overlaps the cement E ­ enamel, C- cement, D - dentin Figure 4. Light microscopy findings of morphological variations of the cemento-enamel junction (CEJ) showing a distance between the two mineralized tissues with initial caries - denuded dentin-a gap. E ­ enamel, C- cement, DC ­ dentine caries I ­ Cement overlaps enamel II - Enamel overlaps cement III -Cement and enamel abut each other with no overlap IV -Gap between cement and enamel We analyzed the distribution of the mutual relationships between the cement and enamel including all dissections of teeth regardless of gender, tooth type and age of the patient. The most common relationship was that cement and enamel abutted each other with no overlap, no significant differences were observed as The distribution of the four types of mineralized dental tissues in the region of CEJ is provided in Table 1. Table1. Distribution of the relationship between mineralized tissues at the cemento-enamel junction in the total sample (n=60) Type of CEJ I II III IV n=60 20 8 22 10 % 33.3% 13.3% 36.7% 16.7% compared to the situation when the cement overlapped the enamel. In contrast, the mentioned cases of CEJ were significantly more distributed than the other two types, i.e. when there was a gap between the cement and the enamel and when the enamel overlapped the cement. individual (11,12). The neck region of the tooth was mostly investigated for cervical and radicular caries, increased sensitivity of the teeth and the frequent occurrence of cervical erosion (13,14). Young people are increasingly using refreshing drinks which contain acidic and erosive components. In the case of the unfavorable relationship of the cement and enamel, the exposed dentin is a subject to demineralization and erosion. Furthermore, in addition to diverse chemical and physical factors present in the oral environment, improper brushing of teeth may disturb the morphology of CEJ causing the exposure of dentin (2). The ratio of cement and enamel varies, not only between individuals but also between the types of teeth from the same person, even in different sections of the same tooth. Our sample consisted of teeth extracted from females and males of various ages and from both jaws, as one previous study already showed that age of patients, as well as the jaw of extracted tooth, do not significantly influence the results (2). The findings of this study showed a substantial proportion (16.7%) of cases when the exposed dentine was present in the region of the neck of the tooth. Therefore, we recommend that certain clinical procedures, such as the placement of hooks and metal prosthetics covers, removal of stones and concrements, and particularly whitening of teeth, should be carefully performed. DISCUSSION Cement-enamel border has been studied using a variety of methods such as microscopy (2), scanning electron microscopy (6), morphogens and embryonicanalysis (7,8). Since Choquet (9) in 1899 first described the four mutual relationships between the cement and enamel in CEJ region, all of these methods were used for the classification,which includes the following relationships: 1. The cement overlaps the enamel, 2. The enamel overlaps the cement, 3. The enamel and cement abut each other with no overlap, and 4. There is a space between the enamel and cement, with exposed dentin in-between. In our study, using the light microscopy, we confirmed the existence of all relationships between the cement and enamel as described by Choquet (9). However, some researchers were unable to find the relationship when the enamel overlaps the cement (10). Roa et al. (5) reported the four relationships between the cement and enamel that was described by Choquet in a sample of 68 teeth (9). In their findings, 51.9% of the cases described the relationship when the cement and enamel were in contact, whereas 42.4% of the cases showed that the enamel overlapped the cement. Our findings also showed that the two most common relationships between the cement and enamel were when the cement and enamel were in contact (36.7%), and when the cement overlapped the enamel (33.3%). We determined that the presence of the relationship when the enamel overlapped the cement accounted for 13.3%, which was similar to the distribution of cases when the enamel and cement were not in contact (16.7%). In the latter case, we observed the exposed dentin, demineralization, cervical and root caries. The importance of CEJ in periodontics and restorative odontology is increasing with aging of an CONCLUSION This study showed that the cement-enamel border is an important anatomical structure of the tooth with different morphological variations.Therefore, it has substantial importance for the proper implementation of certain dental procedures that take place in the region of the neck of the tooth and for the appropriate brushing of teeth. Otherwise, the morphology of CEJ may be violated, with the occurrence of increased tooth sensitivity to physical and chemical agents as well as to the development of pathological processes in the neck of the tooth. Nenad Stosi, Stefan Daci, Dragica Daci Simonovi

Journal

Acta Facultatis Medicae Naissensisde Gruyter

Published: Sep 1, 2015

References