RESUMO
OBJECTIVES: The abutments produced with circular symmetry failed to accurately replicate the natural teeth's cervical shapes. The purpose of this study was to measure cervical cross-sections of maxillary anterior teeth using cone beam computed tomography (CBCT) images to design anatomic healing abutments. MATERIALS AND METHODS: CBCT data of 61 patients were analyzed using Ez3D Plus software. Measurements were taken at the cemento-enamel junction (CEJ) and 1 mm coronal to CEJ for maxillary central incisors, lateral incisors, and canines. Various parameters, including area, perimeter, and eight line segments in the distal (a), disto-palatal (b), palatal (c), mesio-palatal (d), mesial (e), mesio-labial (f), labial (g), and disto-labial (h) directions, were used to describe dental neck contours. The ratios (f/b and h/d) were analyzed, and differences based on sex and dental arch morphology were explored. RESULTS: Significant differences were found in area and perimeter between males and females, but not in f/b and h/d ratios. Differences in the f/b ratio were observed among dental arch morphologies for maxillary central incisors, lateral incisors, and canines. CONCLUSIONS: CBCT measurements of cervical cross-sections provide more accurate data for designing anatomic healing abutments. The fabrication of anatomical healing abutments needs to consider the influence of gender on cervical size and to explore the potential effect of arch shape on cervical morphology. CLINICAL SIGNIFICANCE: The novel method provides detailed measurements for the description of dental cervical contours for patients with bilateral homonymous teeth missing. The measurements of this study could be utilized to design more accurate anatomic healing abutments to create desired morphology of peri-implant soft tissue.
Assuntos
Tomografia Computadorizada de Feixe Cônico , Dente Suporte , Maxila , Colo do Dente , Humanos , Tomografia Computadorizada de Feixe Cônico/métodos , Maxila/diagnóstico por imagem , Maxila/anatomia & histologia , Colo do Dente/diagnóstico por imagem , Colo do Dente/anatomia & histologia , Feminino , Adulto , Masculino , Incisivo/diagnóstico por imagem , Incisivo/anatomia & histologia , Pessoa de Meia-Idade , Dente Canino/diagnóstico por imagem , Dente Canino/anatomia & histologiaRESUMO
Cementoenamel junction is an anatomical landmark which indicates the meeting point of enamel of the crown and the cementum of the root. It is an important reference point in clinical dentistry as well as in dental radiography. The present study is done to describe the distribution of the mineralized tissue at the cementoenamel junction in relation to various surfaces of the premolars. The study sample consisted of 89 permanent maxillary and mandibular premolars from both males and females extracted for orthodontic reasons. They were stained with carbol fuchsin and observed under a dissecting microscope to identify the following tissue interrelationships at the cementoenamel junction: cementum overlapping the enamel; edge-to-edge relationship between enamel and cementum; gap between the enamel and cementum and enamel overlapping the cementum. The cementum overlapping the enamel interrelationship was predominant in the buccal and lingual surfaces of both first and second maxillary premolars, while the edge-to-edge relationship and the presence of a gap between the enamel and the cementum relationship were abundant in distal and mesial sides. Enamel overlapping the cementum was recorded only in a very small proportion of the sample. A good understanding about the morphological variations at the cementoenamel junction area is very important and this area should be handled carefully during routine dental procedures such as dental bleaching, orthodontic treatment, placement of rubber dam and placement of dental materials.
Assuntos
Dente Pré-Molar/anatomia & histologia , Colo do Dente/anatomia & histologia , Adolescente , Criança , Feminino , Humanos , Masculino , Sri LankaRESUMO
The morphology of the alveolar bone at the maxillary anterior teeth in periodontitis patients was evaluated by cone-beam computed tomography (CBCT) to investigate the distribution of alveolar defects and provide guidance for clinical practice. Ninety periodontitis patients and 30 periodontally healthy individuals were selected to determine the morphology of the alveolar bone at the maxillary anterior teeth according to the degree of bone loss, tooth type, sex and age. The differences in the dimensions between periodontitis patients and healthy individuals were compared, and the distribution of alveolar bone defects was analyzed. A classification system was established regarding the sagittal positions and angulations of the teeth. The buccal residual bone was thicker and the lingual bone was thinner in the periodontitis patients than in the periodontally healthy individuals, and there were differences between the different tooth types, sexes and age subgroups. The buccal undercut was close to the alveolar ridge, while fenestration was reduced and the apical bone height was higher in periodontitis patients than in periodontally healthy individuals. The apical bone height increased with the aggravation of bone loss and age. The proportions of different sagittal positions changed with the aggravation of bone loss. Moreover, the teeth moved more buccally regarding the positions of the maxillary anterior teeth. The morphology of the alveolar bone at the maxillary anterior teeth differed between periodontitis patients and healthy individuals, and the differences were related to the degree of bone loss, tooth type, sex and age.
Assuntos
Processo Alveolar/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico/métodos , Incisivo/diagnóstico por imagem , Maxila/diagnóstico por imagem , Periodontite/diagnóstico por imagem , Adulto , Processo Alveolar/anatomia & histologia , Feminino , Humanos , Incisivo/anatomia & histologia , Masculino , Maxila/anatomia & histologia , Estudos Retrospectivos , Ápice Dentário/anatomia & histologia , Ápice Dentário/diagnóstico por imagem , Colo do Dente/anatomia & histologia , Colo do Dente/diagnóstico por imagemRESUMO
To investigate the prevalence of different patterns of cemento-enamel junction (CEJ) morphology under swept-source optical coherence tomography (SS-OCT). One hundred extracted human teeth were used consisting of incisors, premolars, and molars. Each sample was observed for every 500 µm circumferentially along CEJ and OCT images of the pattern were noted. Microscopic observations were done for the representative sample using confocal laser scanning microscope (CLSM) and transmission electron microscope (TEM). The OCT images exhibited four CEJ patterns: edge-to-edge (type I), exposed dentin (type II), cementum overlapping enamel (type III), and enamel overlapping cementum (type IV). The prevalence of CEJ patterns was further statistically considered for mesial, distal, buccal, and lingual surfaces. The real-time imaging by SS-OCT instantly determined CEJ morphology. CLSM and TEM observation revealed morphological features along CEJ, which corresponded to OCT images of CEJ anatomy. OCT results showed 56.8% of type I pattern predominantly found on proximal surfaces, followed by 36.5% of type II pattern on buccal and lingual surface, 6.4% of type III pattern, and 0.3% of type IV pattern. There was a significant difference in prevalence of CEJ patterns among different types of teeth, but there was no statistically significant difference among the four surfaces in each type of teeth. OCT is a non-invasive diagnostic tool to examine the CEJ patterns along the entire circumference. OCT observation revealed even minor dentin exposure that would need clinical and home procedures to prevent any symptoms.
Assuntos
Esmalte Dentário/anatomia & histologia , Esmalte Dentário/diagnóstico por imagem , Tomografia de Coerência Óptica , Colo do Dente/anatomia & histologia , Colo do Dente/diagnóstico por imagem , Dente Pré-Molar/anatomia & histologia , Dente Pré-Molar/diagnóstico por imagem , Humanos , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Dente Molar/anatomia & histologia , Dente Molar/diagnóstico por imagemRESUMO
BACKGROUND: Cementoenamel junction represents the demarcation between enamel covered crown and cementum covered root surface. There is paucity of population specific data of the morphological variability of cementoenamel junctions of permanent and primary teeth. The objective of this study was to investigate the morphological diversity and interrelationship of cementoenamel junction of premolar and molar teeth in permanent dentition of a sample of Pakistani population with potential forensic and anthropological implications. METHODS: This cross-sectional study was conducted at Oral Biology department of Dr Ishrat ul Ebad khan institute of oral health science, Dow University from March till September 2016. Seventy-five maxillary and mandibular permanent premolar and molars from adult patients of both sexes were selected and sectioned. Longitudinal ground sections were prepared to study the morphological interrelationship between Cementum and Enamel in each specimen to be viewed under light microscope. A chi-square test was applied between the categorical variables. RESULTS: Results showed 57.3% of sections had cementum overlapping enamel interrelation, 32% showed edge to edge cementum and enamel relation and 9.3% showed that cementum and enamel failed to meet resulting in exposed dentine, while 1.3% sample showed enamel over cementum relation. No significant correlation was found between gender, type of tooth, maxillary, mandibular arches and the morphological variation of CEJ (p>0.05). CONCLUSIONS: It can be concluded that there are considerable morphological variations in CEJ of premolars and molars with preponderance of cementum overlapping enamel in these teeth. Based on these findings, dentists are advised to be mindful of dental procedures involving the CEJ and that these interventions should be performed meticulously avoiding any detachment of cementum and subsequent exposure of dentin resulting in dentin hypersensitivity.
Assuntos
Dente Pré-Molar/anatomia & histologia , Dente Molar/anatomia & histologia , Colo do Dente/anatomia & histologia , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Paquistão/epidemiologiaRESUMO
OBJECTIVES: The aim of this work was to compare the duration of treatment between orthodontic treatment combined with piezocorticision (OT-PC) and conventional orthodontic treatment (COT), as well as to evaluate the safety, inflammatory process, periodontal health, and soft tissue healing in the OT-PC group. METHODS: Twelve patients were included in each group, and their treatment times were compared for preliminary bracket alignment (PBA) and for overall treatment. In the OT-PC group, the inflammatory process was evaluated by quantifying cytokines in the gingival crevicular fluid. A calibrated examiner measured the probing depth (PD), the distance between the gingival margin and the cementoenamel junction (GM-CEJ), and the clinical attachment level (CAL), before and after OT-PC. The presence of gingival scars was evaluated. Bone and root injuries were assessed with the use of cone-beam computed tomography. RESULTS: The treatment time was significantly reduced in the OT-PC group for PBA in both maxilla (45%; P = 0.001) and mandible (31%; P = 0.023), as well as for overall treatment (52%; P < 0.0001). Although not statistically significant, several inflammatory mediators demonstrated peaks at 3-5 and 16 weeks. There were not significant changes in PD and GM-CEJ after OT-PC treatment, unlike CAL (0.09 ± 0.12 mm; P = 0.024); 47.5% of piezocorticisions caused gingival scars. Only one patient showed no scars. Four cortical bones did not heal completely, and 2 roots had piezoelectric injuries. CONCLUSION: OT-PC was effective at reducing the orthodontic treatment time.
Assuntos
Citocinas/metabolismo , Líquido do Sulco Gengival/química , Má Oclusão/terapia , Ortodontia Corretiva/métodos , Piezocirurgia/métodos , Adolescente , Adulto , Terapia Combinada , Diagnóstico por Imagem , Feminino , Gengiva/anatomia & histologia , Humanos , Masculino , Satisfação do Paciente , Perda da Inserção Periodontal , Índice Periodontal , Fatores de Tempo , Colo do Dente/anatomia & histologia , Resultado do TratamentoRESUMO
OBJECTIVE: The aim of this study is to assess whether there is a correlation between buccal bone thickness and mean alveolar bone thickness around the central teeth using CBCT images. MATERIALS AND METHODS: Three points were selected at 3, 6 and 9 mm from the cemento-enamel junction, respectively, perpendicular to the long axis of the measuring points made to determine the width of the alveolar bone ridge. The arithmetic mean of the length measurements was taken as the average alveolar bone thickness. To determine the average buccal alveolar bone thickness, the buccal bone length was measured perpendicular to the long axis of the tooth from these 3 points, and the average of the measurements was taken from these 3 points. RESULTS: The mean coronal, mid-root, and apical third root widths of the maxillary, left central incisors were 7.72±0.60, 8.64 ± 0.93, and 9.23±1.45 mm, respectively and the mean widths of the buccal alveolar bone at the coronal, mid-root, and apical third root positions of the left central incisor were 1.18±0.39, 1.15±0.44, and 1.06±0.50 mm, respectively. The Spearman correlation coefficients were 0.194 and 0.191 for the left and right central incisors, respectively. CONCLUSIONS: There was no statistically significant difference between the alveolar bone thickness averages of the left and right central incisors, but the alveolar bone thickness was found to be thicker in males than females. Although the mean of alveolar and buccal bone thicknesses was positively correlated the statistical analysis demonstrated the correlation between the mean of alveolar and buccal bone thicknesses is not significant.
Assuntos
Processo Alveolar/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico/métodos , Incisivo/diagnóstico por imagem , Maxila/diagnóstico por imagem , Zigoma/diagnóstico por imagem , Adulto , Processo Alveolar/anatomia & histologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Masculino , Maxila/anatomia & histologia , Pessoa de Meia-Idade , Boca , Colo do Dente/anatomia & histologia , Colo do Dente/diagnóstico por imagem , Zigoma/anatomia & histologiaRESUMO
OBJECTIVE: To investigate the mesial cervical concavity of maxillary first premolars and its relationship with root and canal configuration using cone-beam computed tomography (CBCT). DESIGN: Images of maxillary first premolars (nâ¯=â¯1056) were collected from patients (nâ¯=â¯601) who had undergonein vivo CBCT scanning. The root and canal number and morphology were evaluated. The following measurements of the mesial cervical concavity of the maxillary first premolars were evaluated in section images: dentine thickness (in concavity at the cemento-enamel junction), concavity angle, depression depth (distance from mesial dentinal surface at concavity to mesial proximity), concavity position (distance from mesial dentinal wall at invagination to the top of the mesial marginal ridge). The reliability of the data was analyzed with an unpaired Student's t test and Fisher's exact test. RESULTS: The percentages of maxillary first premolars with one root, two, and three roots were 55.5%, 43.7%, and 0.8% respectively. Mesial cervical concavity was recorded in 64.5% of single-root maxillary premolars. The prevalence of two-root maxillary first premolars with mesial cervical concavity was 73.8%. The means of the aforementioned four measurements were 1.705, 147.9, 1.640, and 5.247â¯mm. The values of dentine thickness (mm), depression depth (mm), and concavity position (mm) of the mesial cervical concavity were largest in two-root maxillary first premolars. The smallest concavity angle of the mesial cervical concavity was found in three-root maxillary first premolars. CONCLUSIONS: There is a high prevalence of mesial cervical concavity among maxillary first premolars. The mesial root concavity is more prevalent in single-rooted maxillary first premolars when there are two canals present, and its prevalence and degree of concavity increase with the number of roots.
Assuntos
Dente Pré-Molar/anatomia & histologia , Dente Pré-Molar/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico/métodos , Maxila/anatomia & histologia , Maxila/diagnóstico por imagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Dentição Permanente , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Colo do Dente/anatomia & histologia , Colo do Dente/diagnóstico por imagem , Raiz Dentária/anatomia & histologia , Raiz Dentária/diagnóstico por imagemRESUMO
SureFil SDR is a flowable resin-based composite that allows a single incremental bulk placement. The marginal seal of SureFil SDR at the gingival margins of class II restorations located apical to the cemento-enamel-junction (CEJ) has not been adequately evaluated compared to those located occlusal to the CEJ. Forty class II cavities were prepared in human molars. The gingival margins of 20 preparations were located 0.5 mm occlusal to the CEJ, and the other 20 preparations were located 0.5 mm apical to the CEJ. The cavities surfaces were bonded with XenoV dental adhesive and filled with SDR in one bulk increment up to 4 mm, after which they were covered with CeramX. The teeth were subjected to thermo-and load-cycling, and their gingival margins were exposed to 0.5% basic-fuchsin solution. The specimens were sectioned mesio-distally and scored for microleakage. A Wilcoxon test for pairwise comparison was performed to determine significance. Dye penetration was observed in 30% of the 20 restorations with cavo-surface margins located occlusal to the CEJ and in 55% of the 20 restorations with cavo-surface margins located apical to the CEJ. The bulk-fill flowable resin base SureFil SDR with XenoV dental adhesive provided a better marginal seal in class II restorations with gingival margins above the CEJ compared to restorations with gingival margins below the CEJ. SDR should not be recommended for class II cavity preparations with gingival margins located below the CEJ.
Assuntos
Resinas Compostas , Preparo da Cavidade Dentária , Restauração Dentária Permanente , Gengiva/anatomia & histologia , Humanos , Colo do Dente/anatomia & histologiaRESUMO
OBJECTIVE: To analyze the buccal bone thickness, bone depth, and cortical bone depth of the mandibular buccal shelf (MBS) to determine the most suitable sites of the MBS for mini-screw insertion. MATERIALS AND METHODS: The sample included cone-beam computed tomographic (CBCT) records of 30 adult subjects (mean age 30.9 ± 7.0 years) evaluated retrospectively. All CBCT examinations were performed with the i-CAT CBCT scanner. Each exam was converted into DICOM format and processed with OsiriX Medical Imaging software. Proper view sections of the MBS were obtained for quantitative and qualitative evaluation of bone characteristics. RESULTS: Mesial and distal second molar root scan sections showed enough buccal bone for mini-screw insertion. The evaluation of bone depth was performed at 4 and 6 mm buccally to the cementoenamel junction. The mesial root of the mandibular second molar at 4 and 6 mm showed average bone depths of 18.51 mm and 14.14 mm, respectively. The distal root of the mandibular second molar showed average bone depths of 19.91 mm and 16.5 mm, respectively. All sites showed cortical bone depth thickness greater than 2 mm. CONCLUSIONS: Specific sites of the MBS offer enough bone quantity and adequate bone quality for mini-screw insertion. The insertion site with the optimal anatomic characteristics is the buccal bone corresponding to the distal root of second molar, with screw insertion 4 mm buccal to the cementoenamel junction. Considering the cortical bone thickness of optimal insertion sites, pre-drilling is always recommended in order to avoid high insertion torque.
Assuntos
Parafusos Ósseos , Osso Cortical/anatomia & histologia , Osso Cortical/cirurgia , Implantes Dentários , Mandíbula/anatomia & histologia , Mandíbula/cirurgia , Procedimentos de Ancoragem Ortodôntica , Adulto , Densidade Óssea , Tomografia Computadorizada de Feixe Cônico/métodos , Osso Cortical/diagnóstico por imagem , Arco Dental/anatomia & histologia , Arco Dental/diagnóstico por imagem , Arco Dental/cirurgia , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Masculino , Mandíbula/diagnóstico por imagem , Dente Molar/diagnóstico por imagem , Dente Molar/cirurgia , Procedimentos de Ancoragem Ortodôntica/instrumentação , Procedimentos de Ancoragem Ortodôntica/métodos , Estudos Retrospectivos , Software , Colo do Dente/anatomia & histologia , Colo do Dente/diagnóstico por imagem , Colo do Dente/cirurgia , Raiz Dentária/anatomia & histologia , Raiz Dentária/diagnóstico por imagem , Adulto Jovem , Zigoma/anatomia & histologia , Zigoma/diagnóstico por imagemRESUMO
OBJECTIVE: This study sought to assess the relationship between facial gingival and bone dimensions in maxillary anterior teeth region using cone beam computed tomography (CBCT). DESIGN: This study assessed 621 maxillary anterior teeth in 144 patients. In the sagittal plane, facial bone thickness (BT) and gingival thickness (GT) were measured at the crestal level and at 2, 4 and 6mm apical to the cementoenamel junction (CEJ). The dentogingival complex (DGC) dimensions and the distance from the CEJ to bone crest were also measured on CBCT scans. To determine the gingival biotype, GT at 2mm apical to the gingival margin was measured and GT <1.5mm was categorized as thin while GT ≥1.5mm was categorized as thick. The data were analyzed using SPSS version 21 via repeated measures ANOVA and the Cochrane's Q, chi-square and independent samples t-tests. RESULTS: The BT around the maxillary central and lateral incisors and canine teeth at 4 and 6mm apical to the CEJ was significantly different in thick and thin gingival biotypes (P<0.05). The mean GT at 2 and 4mm apical to the CEJ was significantly different around central and lateral incisors (P<0.05). Thickness of crestal bone was significantly different between the two gingival biotypes around central and lateral incisors (P<0.05). CONCLUSION: The two gingival biotypes had significantly different mean BT; different biotypes and their relationship to BT varied around anterior maxillary teeth.
Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Face/anatomia & histologia , Gengiva/anatomia & histologia , Incisivo/anatomia & histologia , Maxila/anatomia & histologia , Adulto , Processo Alveolar/anatomia & histologia , Processo Alveolar/diagnóstico por imagem , Bochecha/anatomia & histologia , Bochecha/diagnóstico por imagem , Distribuição de Qui-Quadrado , Dente Canino/anatomia & histologia , Dente Canino/diagnóstico por imagem , Face/diagnóstico por imagem , Feminino , Gengiva/diagnóstico por imagem , Humanos , Incisivo/diagnóstico por imagem , Lábio/anatomia & histologia , Lábio/diagnóstico por imagem , Masculino , Maxila/diagnóstico por imagem , Pessoa de Meia-Idade , Colo do Dente/anatomia & histologia , Colo do Dente/diagnóstico por imagemRESUMO
Objective: To examine the root position of the maxillary central incisors and to provide clinical reference before the immediate implant placement. Methods: Cone-beam CT (CBCT) data of the maxillary central incisors of 934 patients (934 incisors) was selected and the root position classsified. The sagittal root position in the alveolar bone was classified as buccal, middle, or palatal. The buccally positoined type was further classified into three subtypes of â ,â ¡, and â ¢. Results: Most of the maxillary incisor root (95.4% [891/934]) was positioned buccally. Among the buccal-type incisors, the subtypes â , â ¡ and â ¢ accounted for 47.5% (423/891), 44.2% (394/891), and 8.3% (74/891). In the 4 mm apical to the cemento-enamel junction and the middle of the root, the thickest buccal bone wall was 0.86 and 0.95 mm, the thickest palatal bone wall was 1.65 and 2.37 mm. In the apical location, the thickest buccal bone wall was 1.89 mm, the thickest palatal bone wall was 7.83 mm. Conclusions: Most of the maxillary central incisors studied are positioned buccally, and half of these patients have adequate buccal bone and are suitable for immediate implant placement.
Assuntos
Incisivo/diagnóstico por imagem , Raiz Dentária/diagnóstico por imagem , Adulto , Processo Alveolar/anatomia & histologia , Processo Alveolar/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico , Humanos , Incisivo/anatomia & histologia , Maxila/anatomia & histologia , Maxila/diagnóstico por imagem , Palato/anatomia & histologia , Palato/diagnóstico por imagem , Colo do Dente/anatomia & histologia , Colo do Dente/diagnóstico por imagem , Raiz Dentária/anatomia & histologia , ZigomaRESUMO
OBJECTIVE: To evaluate the coronal microleakage of packable composite using conventional incremental and posterior bulk fill flowable composite using Smart Dentine Replacement Single Step technique in the cervical margins of class II cavities in dentine using the dye penetration method. STUDY DESIGN: In-vitroInterventional study. PLACE AND DURATION OF STUDY: Department of Operative Dentistry, Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences (DIKIOHS), Karachi, from November 2012 to April 2013. METHODOLOGY: One hundred and twenty extracted teeth (molars and premolars) were collected and randomly divided into two experimental groups (n=60 each) and were stored in normal saline until used. Fractured samples were excluded. Standardized class II proximal box only cavities were prepared and restored with conventional methacrylate based composite using incremental technique (Group A, n=40) and low stress methacrylate resin based composite SDR using single step technique (Group B, n=40). Samples were sectioned horizontally below the cervical margins and specimen disks were prepared. The specimens were thermocycled and sealed with acid resistant varnish leaving a 1-mm interface around cervical margin and immersed in 2% methylene blue buffered solution for 24 hours. Leakage was scored 0 - 4 and measured in mm. It washed and sectioned to evaluate under stereomicroscope. RESULTS: Mean penetration was 2.4280 ±0.79 mm for Group Aand 1.015 ±0.45 mm for Group B (p < 0.001). Maximum dye penetration score for group Awas 4 and group B was 3. CONCLUSION: SDR technique in combination with total etch technique at the cervical margin of class II restorations improved the marginal seal, when were placed in dentine and thermocycled.
Assuntos
Resinas Compostas/química , Colagem Dentária/métodos , Infiltração Dentária/prevenção & controle , Materiais Dentários/química , Restauração Dentária Permanente/métodos , Adesivos Dentinários/química , Cimentos de Resina/química , Colo do Dente , Corantes , Resinas Compostas/uso terapêutico , Preparo da Cavidade Dentária/classificação , Preparo da Cavidade Dentária/métodos , Infiltração Dentária/classificação , Adaptação Marginal Dentária , Restauração Dentária Permanente/classificação , Dentina/anatomia & histologia , Humanos , Azul de Metileno , Colo do Dente/anatomia & histologiaRESUMO
BACKGROUND: The objective of this retrospective case-control study was to measure the maxillary lateral incisor root dimensions and quantify the labial and palatal bone in patients with unilateral maxillary lateral incisor agenesis (MLIA) after orthodontic treatment and compare them to non-agenesis controls using cone beam computed tomography. METHODS: The labiopalatal and mesiodistal root dimensions, mesiodistal coronal dimensions, and labiopalatal bone and alveolar ridge widths of the maxillary lateral incisor were assessed on posttreatment cone beam computed tomography scans of 15 patients (mean age 16.5 ± 3.4 years, 9 females and 6 males) with maxillary lateral incisor agenesis and 15 gender-matched patients (mean age 16.08 ± 3.23 years) with no dental agenesis or anterior Bolton discrepancy. The Mann-Whitney test was used to distinguish any differences in root width, crown width, or changes in labial or palatal bone width between the two groups. RESULTS: The median labiopalatal root width was narrower in the MLIA group at the level of the cementoenamel junction (CEJ) to 8 mm apical of the CEJ compared to controls (p ≤ 0.009). The mesiodistal root width was significantly reduced in the MLIA group at the CEJ and at 4 mm apical to the CEJ. The labiopalatal alveolar ridge width was significantly decreased at 2 mm apical to the CEJ in MLIA group. The mesiodistal crown width was significantly smaller in the MLIA group at both the incisal edge and at the crown midpoint. The bone thickness was similar in both groups. CONCLUSIONS: Coronal and root dimensions in patients with MLIA were reduced compared to controls. Alveolar ridge width was also reduced in patients with MLIA, although bone thickness was not different than controls.
Assuntos
Processo Alveolar/anatomia & histologia , Processo Alveolar/diagnóstico por imagem , Anodontia/diagnóstico por imagem , Incisivo/anormalidades , Incisivo/anatomia & histologia , Incisivo/diagnóstico por imagem , Raiz Dentária/anatomia & histologia , Raiz Dentária/diagnóstico por imagem , Adolescente , Adulto , Anodontia/terapia , Estudos de Casos e Controles , Criança , Tomografia Computadorizada de Feixe Cônico/métodos , Feminino , Humanos , Imageamento Tridimensional/métodos , Masculino , Maxila/anatomia & histologia , Maxila/diagnóstico por imagem , Ortodontia Corretiva/métodos , Palato/anatomia & histologia , Estudos Retrospectivos , Estatísticas não Paramétricas , Colo do Dente/anatomia & histologia , Colo do Dente/diagnóstico por imagem , Coroa do Dente/anatomia & histologia , Coroa do Dente/diagnóstico por imagem , Técnicas de Movimentação Dentária/métodos , Adulto JovemRESUMO
PURPOSE: To evaluate the effect of cervical margin relocation (CMR) for crowns designed using CAD/CAM technology, and made of pre-cured resin or lithium disilicate, before and after thermomechanical loading. The test hypothesis was that the marginal quality of the crowns would not be influenced by the CMR with composite resins before or after thermomechanical loading. MATERIALS AND METHODS: Standard crown preparations were created in 40 human molars. The margins were located in enamel, except for the mesial proximal box, where the cervical margin was 2.0 mm below the cementoenamel junction, with 4.0 mm in the buccolingual and 2.0 mm in the mesiodistal dimension. For the CMR technique, a 2-mm layer of conventional or flowable composite resin was applied to the mesial box. Using the Cerec CAD/CAM system, 40 standard crowns were prepared, and restorations were luted using a dual-curing adhesive cement. SEM analysis was performed using epoxy resin replicas before and after loading to assess the marginal quality of interfaces of the mesial proximal box with CMR/crown and the distal face of the tooth without CMR. Statistical differences between groups were analyzed using the Kruskal-Wallis test and Bonferroni's post-hoc test. RESULTS: The null hypothesis was accepted, since no statistically significant differences were found in marginal quality before and after thermomechanical cycling (p > 0.05). CONCLUSION: The implementation of CMR before and after thermomechanical cycling had no effect on the quality of cervical margins. To establish whether CMR is a suitable procedure for the adhesive luting of composite resin crowns in deep proximal boxes, additional studies are required.
Assuntos
Resinas Compostas/química , Desenho Assistido por Computador , Coroas , Adaptação Marginal Dentária , Materiais Dentários/química , Preparo Prostodôntico do Dente/métodos , Esmalte Dentário/anatomia & histologia , Porcelana Dentária/química , Planejamento de Prótese Dentária , Humanos , Técnicas In Vitro , Teste de Materiais , Microscopia Eletrônica de Varredura , Nanocompostos/química , Nanopartículas/química , Técnicas de Réplica , Cimentos de Resina/química , Autocura de Resinas Dentárias/métodos , Dióxido de Silício/química , Estresse Mecânico , Temperatura , Fatores de Tempo , Colo do Dente/anatomia & histologia , Água/químicaRESUMO
SUMMARY: Dental wear has been used extensively in osteoarchaeological studies as a means of exploring dietary patterns and the use of teeth as tools. The present paper aims to test whether crown height can be predicted for premolars and molars based on the mesiodistal and buccolingual diameters of these teeth at the level of the cementoenamel junction (CEJ). Multiple linear regression was used with crown height as dependent variable and diameters at the CEJ as predictors. Our results found that there are cases where the impact of one predictor appears to be statistically significant. However, even in these cases the 95% confidence interval for the predicted value is so broad that makes the accurate determination of the crown height based on the buccolingual or/and mesiodistal diameters at the CEJ impossible.
Assuntos
Antropologia Física/métodos , Antropometria/métodos , Colo do Dente/anatomia & histologia , Coroa do Dente/anatomia & histologia , Desgaste dos Dentes/patologia , Adolescente , Adulto , Criança , Feminino , Humanos , Masculino , Adulto JovemRESUMO
BACKGROUND: The aim of this study was to evaluate the influence of cervical preflaring on apical transportation in curved root canals prepared using the Reciproc and WaveOne reciprocating file systems. METHODS: Sixty curved canals were instrumented using Reciproc R25 and WaveOne Primary files, with and without preflaring (n = 15). A double-digital technique was used to digitally superimpose the file before instrumentation (#15 K-file) on the final apical reciprocating file (#25/08). The angle between the tip of the initial and final file was measured and recorded. Groups were compared using the Kruskal-Wallis test, and significance was set at p < 0.05. RESULTS: The mean and standard deviation for apical transportation was 0.93 ± 2.48 for the Reciproc Group, 0.84 ± 1.94 for the Preflaring + Reciproc Group, 0.40 ± 1.14 for the WaveOne Group, and 0.83 ± 2.20 for the Preflaring + WaveOne Group. No statistically significant differences were found among the groups (p = 0.9509). CONCLUSIONS: Under the conditions of this study, cervical preflaring did not influence apical transportation in curved root canals instrumented using Reciproc R25 and the WaveOne Primary files. Based on the in vitro measurements of apical transportation, the reciprocating files may be used without preflaring in curved root canals.
Assuntos
Cavidade Pulpar/anatomia & histologia , Preparo de Canal Radicular/instrumentação , Ligas Dentárias/química , Cavidade Pulpar/diagnóstico por imagem , Desenho de Equipamento , Humanos , Processamento de Imagem Assistida por Computador/métodos , Níquel/química , Radiografia Dentária Digital/métodos , Preparo de Canal Radicular/métodos , Titânio/química , Ápice Dentário/anatomia & histologia , Colo do Dente/anatomia & histologia , TorqueRESUMO
To determine the frequency of apical and cervical curvatures in human molars using the radius method and cone-beam computed tomography (CBCT) images. Four hundred images of mandibular and maxillary first and second molars were selected from a database of CBCT exams. The radius of curvature of curved root canals was measured using a circumcenter based on three mathematical points. Radii were classified according to the following scores: 0 - straight line; 1 - large radius (r > 8 mm, mild curvature); 2 - intermediate radius (r > 4 and r < 8 mm, moderate curvature); and 3 - small radius (r ≤ 4 mm, severe curvature). The frequency of curved root canals was analyzed according to root canal, root thirds, and coronal and sagittal planes, and assessed using the chi-square test (significance at α = 0.05). Of the 1,200 evaluated root canals, 92.75% presented curved root canals in the apical third and 73.25% in the cervical third on coronal plane images; sagittal plane analysis yielded 89.75% of curved canals in the apical third and 77% in the cervical third. Root canals with a large radius were significantly more frequent when compared with the other categories, regardless of root third or plane. Most root canals of maxillary and mandibular first and second molars showed some degree of curvature in the apical and cervical thirds, regardless of the analyzed plane (coronal or sagittal).
Assuntos
Dente Molar/anatomia & histologia , Ápice Dentário/anatomia & histologia , Colo do Dente/anatomia & histologia , Tomografia Computadorizada de Feixe Cônico , HumanosRESUMO
To determine the frequency of apical and cervical curvatures in human molars using the radius method and cone-beam computed tomography (CBCT) images. Four hundred images of mandibular and maxillary first and second molars were selected from a database of CBCT exams. The radius of curvature of curved root canals was measured using a circumcenter based on three mathematical points. Radii were classified according to the following scores: 0 - straight line; 1 - large radius (r>8 mm, mild curvature); 2 - intermediate radius (r>4 and r<8 mm, moderate curvature); and 3 - small radius (r≤4 mm, severe curvature). The frequency of curved root canals was analyzed according to root canal, root thirds, and coronal and sagittal planes, and assessed using the chi-square test (significance at α=0.05). Of the 1,200 evaluated root canals, 92.75% presented curved root canals in the apical third and 73.25% in the cervical third on coronal plane images; sagittal plane analysis yielded 89.75% of curved canals in the apical third and 77% in the cervical third. Root canals with a large radius were significantly more frequent when compared with the other categories, regardless of root third or plane. Most root canals of maxillary and mandibular first and second molars showed some degree of curvature in the apical and cervical thirds, regardless of the analyzed plane (coronal or sagittal).
.Determinar a frequência de curvaturas apicais e cervicais em molares humanos usando o método do raio de curvatura e imagens de Tomografia Computadorizada de Feixe Cônico (TCFC). Quatrocentas imagens de primeiros e segundos molares superiores e inferiores foram selecionadas a partir de um banco de dados de exames de TCFC. O raio de curvatura dos canais foi medido usando um circuncentro com base em três pontos matemáticos e classificado de acordo com os seguintes escores: 0 - linha reta; 1 - raio grande (r > 8 mm, curvatura suave); 2 - raio intermediário (r > 4 e r < 8, curvatura moderada); 3 - raio pequeno (r ≤ 4 mm, curvatura severa). A frequência de curvaturas foi analisada em função do canal radicular, dos terços da raiz, e dos planos de avaliação (coronal e sagital); e avaliados usando o teste Qui-Quadrado (significância de α=0.05). Dos 1200 canais radiculares avaliados, 92,75% apresentaram curvatura no terço apical e 73,25% no terço cervical quando da análise no plano coronal; a análise do plano sagital revelou 89,75% de canais curvos no terço apical e 77% no terço cervical. Canais radiculares com curvatura suave foram significantemente mais frequentes quando comparados com as demais categorias, independentemente do terço radicular ou do plano. A maioria dos canais radiculares dos primeiros e segundos molares superiores e inferiores apresentou algum grau de curvatura nos terços apical e cervical, independentemente do plano analisado (coronal ou sagital).
.Assuntos
Humanos , Tomografia Computadorizada de Feixe Cônico , Dente Molar/anatomia & histologia , Ápice Dentário/anatomia & histologia , Colo do Dente/anatomia & histologiaRESUMO
This is the second paper in this two-part series. Paper one provided an overview of managing gingival tissue excess and paper two will focus on increasing clinical crown height to facilitate restorative treatment. Crown lengthening is a surgical procedure aimed at the removal of gingival tissue with or without adjunctive bone removal. The different types of procedure undertaken will be discussed over the two papers. In order to provide predictable restorations, care must be taken to ensure the integrity of the margins. If this is not taken into account it can lead to an impingement on the biologic width, which may in turn lead to chronic inflammation resulting in recession or the development of periodontal problems which can be hard to manage. Clinical Relevance: This paper aims to reinforce the need for thorough diagnosis and treatment planning and provides an overview of the various procedures that can be undertaken.