Evaluation of WALA ridge in different facial patterns: A cone-beam computed tomography study.

INTRODUCTION: This retrospective study evaluated the buccal bone thickness in mandibular canine, premolar, and molar areas, using as a reference the WALA ridge in patients with various facial patterns. METHODS: The sample comprised 51 cone-beam computerized tomography scans of subjects divided into 3 groups according to the facial pattern, determined by the Ricketts' VERT index, brachyfacial (group 1), mesofacial (group 2), and dolichofacial (group 3). A quantitative analysis of the buccal bone thickness was made in cone-beam computerized tomography scans in the region of the mandibular dental arch corresponding to the WALA ridge. The intergroup comparison of buccal bone thickness was performed with a 1-way analysis of variance and Tukey tests. RESULTS: Buccal bone thickness was similar among the groups, and it increased progressively from the mandibular first to the second molars. In the canine and premolar regions, the thickness was less and often not visible on tomography. There was no difference in the buccal bone thickness in the mandibular dental arch region corresponding to the WALA ridge reference among facial patterns, except for the mesial roots of the second molars, which were thicker in brachyfacial subjects than in dolichofacial subjects. CONCLUSIONS: The use of the WALA ridge as a clinical reference for individualized orthodontic arch diagramming should be made with caution and independent of the facial pattern.

Miniscrew insertion sites of infrazygomatic crest and mandibular buccal shelf in different vertical craniofacial patterns: A cone-beam computed tomography study.

OBJECTIVE: To identify optimal areas for the insertion of extra-alveolar miniscrews into the infrazygomatic crest (IZC) and mandibular buccal shelf (MBS), using cone beam computed tomography (CBCT) imaging in patients with different craniofacial patterns. METHODS: CBCT reconstructions of untreated individuals were used to evaluate the IZC and MBS areas. The participants were divided into three groups, based on the craniofacial pattern, namely, brachyfacial (n = 15; mean age, 23.3 years), mesofacial (n = 15; mean age, 19.24 years), and dolichofacial (n = 15; mean age, 17.79 years). In the IZC, the evaluated areas were at 11, 13, and 15 mm above the buccal cusp tips of the right and left first molars. In the MBS, the evaluated areas were at the projections of the first molars' distal roots and second molars' mesial and distal roots, at a 4- and 8-mm distance from the cementoenamel junction. Intergroup comparisons were performed with analysis of variance and the Tukey test. RESULTS: There was no statistically significant difference in the IZC bone thickness among the groups. For MBS bone availability, some comparisons revealed no difference; meanwhile, other comparisons revealed increased MBS bone thickness in the brachyfacial (first molars distal roots) and dolichofacial (second molars mesial and distal roots) patterns. CONCLUSIONS: There was no significant difference in the IZC bone thickness among the groups. The facial skeletal pattern may affect the availability of ideal bone thickness for the insertion of extra-alveolar miniscrews in the MBS region; however, this variability is unlikely to be clinically meaningful.

Evaluation of Mandibular First Molars' Axial Inclination and Alveolar Morphology in Different Facial Patterns: A CBCT Study.

OBJECTIVE: The purpose of this study was to evaluate and compare the axial inclination of the mandibular first molars and their respective bone morphology among individuals with different facial patterns. MATERIALS AND METHODS: The sample comprised the cone beam computed tomographies (CBCTs) of 58 subjects divided into three groups according to the facial patterns: 18 brachyfacial (Group 1), with a mean age of 21.58 years; 23 mesofacial (Group 2), with a mean age of 19.14 years; and 17 dolichofacial subjects (Group 3), with a mean age of 19.09 years. Eight variables were evaluated on CBCT scans of each subject: buccal and lingual mandibular height, cervical and middle mandibular width, inclination of mandibular body, inclination of the mandibular molar buccal surface, molar width, molar angulation and tooth/bone angle. Intergroup comparisons were performed with one-way analysis of variance followed by Tukey tests. RESULTS: Buccal mandibular height presented statistically significant difference in the three facial patterns. Lingual mandibular height and mandibular inclination showed to be statistically and significantly smaller in brachyfacial subjects than in the other two groups. Mandibular width presented a statistically significant difference between brachyfacial and mesofacial groups. Negative correlations could be observed between the facial pattern and the buccal and lingual mandibular heights and inclination of the mandibular body. CONCLUSION: Buccal mandibular height was significantly and progressively larger in brachyfacial, mesofacial, and dolichofacial subjects. Lingual mandibular height was significantly smaller in brachyfacial than in mesofacial and dolichofacial subjects. Mandibular width was significantly thicker in brachyfacial than in mesofacial subjects. Brachyfacial subjects had smaller mandibular inclination than mesofacial and dolichofacial subjects.

Mesiodistal dental movement toward remodeled edentulous alveolar ridge: Digital model assessment.

INTRODUCTION: The aims of this study were to compare the changes in posterior dental inclination and angulation, and the posterior tooth crown sizes and alveolar ridge thicknesses consequent to the orthodontic procedures of closing and opening of mandibular first molar edentulous spaces. METHODS: The sample comprised 16 patients (4 men, 12 women) with an initial mean age of 34.17 years and unilateral or bilateral absence of mandibular permanent first molars. The space closure group (SCG) comprised 12 hemiarches with a mandibular first molar edentulous space varying from 2 to 7 mm, orthodontically treated with space closure. The space opening group (SOG) comprised 14 quadrants with a mandibular first molar edentulous space varying from 7.1 to 12 mm, orthodontically treated with space reopening for prosthetic replacement. Digital dental models were obtained before treatment and after space closure or opening, and posterior tooth angulation and inclination, cervico-occlusal crown height, and alveolar ridge thickness were evaluated. Interphase and intergroup comparisons were performed with dependent t tests and t tests, respectively (P <0.05). RESULTS: Mandibular second molar uprighting and changes in buccolingual inclination of the posterior teeth were similar in the groups. The second molar cervico-occlusal crown height increased in the SCG and decreased in the SOG. The alveolar ridge thickness increased in the SCG and remained stable in the SOG. CONCLUSIONS: The only significant intergroup differences were that the second molar cervico-occlusal crown height and the alveolar ridge thickness increased in the SCG, and decreased and remained stable in the SOG.

Movement of mandibular molar into edentulous alveolar ridge: A cone-beam computed tomography study.

INTRODUCTION: The purpose of this study was to evaluate the thickness and height of buccal and lingual alveolar bone of mandibular teeth moved to edentulous areas with a remodeled alveolar ridge. METHODS: The sample included 18 adult patients with unilateral or bilateral absence of mandibular permanent first molars with a mean age of 36.1 years before treatment. The mandibular hemiarches were divided into 3 groups: reopening group (15 hemiarches), closure group (12 hemiarches), and control group (9 hemiarches with no missing teeth). Cone-beam computed tomography scans with a 0.2-mm voxel size were performed 4 months after space closure or reopening. Cross sections 0.2 mm thick passing through the center of the mandibular permanent second molar and second premolar roots were used for measurements of the buccal and lingual bone plate thickness and level. Intergroup comparisons were performed with 1-way analysis of variance followed by Tukey tests (P <0.05). RESULTS: No intergroup differences were found for the alveolar bone statuses of the mandibular second premolar. For the mandibular second molar, the closing group showed significantly smaller buccal and lingual crest levels compared with the control group. CONCLUSIONS: Space closure of missing mandibular first molars caused slight buccal and lingual dehiscences at the mandibular second molar areas.

Avaliação da inclinação axial dos dentes posteriores e sua respectiva morfologia alveolar nos diferentes padrões faciais: uma visão por meio da tomografia computadorizada de feixe cônico / Evaluation of the axial inclination of posterior teeth and their respective alveolar morphology in different facial patterns: a vision by cone beam computed tomography

O objetivo deste estudo foi comparar, por meio de tomografia computadorizada de feixe cônico, a inclinação axial dos dentes posteriores e a morfologia óssea alveolar mandibular entre indivíduos com diferentes padrões faciais. Para isso, foram utilizadas 58 tomografias de indivíduos maiores de 14 anos de idade não tratados ortodonticamente. Os indivíduos foram divididos em 3 grupos de acordo com o padrão facial avaliado pelo índice VERT de Ricketts: Grupo 1: composto por 18 indivíduos com padrão braquifacial, com idade média de 21,58 anos (d.p.=7,43); Grupo 2: composto por 23 indivíduos com padrão mesofacial, com idade média de 19,14 anos (d.p.=5,19); e Grupo 3: composto por 17 indivíduos com padrão dolicofacial, com idade média de 19,09 anos (d.p.=6,89). Foi realizada uma avaliação quantitativa das tábuas ósseas vestibular e lingual dos dentes pósteroinferiores, em tomografias de feixe cônico. As medidas utilizadas foram: altura do osso mandibular vestibular e lingual, largura mandibular cervical e média, inclinação mandibular, inclinação da face vestibular, largura do molar, angulação do molar e ângulo dente/osso. A comparação intergrupos foi realizada com a utilização do teste ANOVA a um critério de seleção e teste de Tukey quando necessário. Para verificar se existe correlação entre o padrão facial e as variáveis estudadas foi utilizado o teste de correlação de Pearson. Os resultados demonstraram que os indivíduos braquifaciais apresentaram uma menor inclinação mandibular quando comparados aos indivíduos mesofaciais e dolicofaciais. Houve diferença significante da altura mandibular vestibular entre os três grupos avaliados, sendo que esta foi menor no grupo braquifacial, intermediária no grupo mesofacial e maior no grupo dolicofacial. A altura mandibular lingual foi menor no grupo braquifacial em comparação aos grupos mesofacial e dolicofacial. A largura mandibular média foi maior nos indivíduos braquifaciais em relação aos mesofaciais...

The aim of this study was to compare, with cone beam computed tomography, the axial inclination of posterior teeth and mandibular alveolar bone morphology among individuals with different facial patterns. For this, 58 CT scans of untreated individuals orthodontically aged more than 14 years were used. The subjects were divided into 3 groups according to the facial pattern evaluated by the VERT index by Ricketts: Group 1 comprised 18 individuals with brachyfacial pattern, with a mean age of 21.58 years (s.d.=7.43); Group 2 comprised 23 individuals with mesofacial pattern, with a mean age of 19.14 years (s.d.=5.19); and Group 3 comprised 17 individuals with dolichofacial pattern, with a mean age of 19.09 years (s.d.=6.89). A quantitative assessment of the buccal and lingual bone plates of the mandibular posterior teeth were made in cone beam CT scans. The variables measured were: buccal and lingual mandibular height, cervical and middle mandibular width, mandibular inclination, inclination of the buccal surface, molar width, molar angle and tooth/bone angle. The intergroup comparison was performed by one-way ANOVA and Tukey test when necessary. To check whether there is a correlation between facial pattern and the variables studied, the Pearson correlation test was used. The results showed that the brachyfacial subjects had a smaller mandibular angle when compared to mesofacial and dolichofacial individuals. There was significant difference in the buccal mandibular height between the three groups, and this was smaller in the brachyfacial group, intermediate in the mesofacial group and larger in the dolichofacial group. Lingual mandibular height was smaller in brachyfacial group when compared to mesofacial and dolichofacial groups. The mean mandibular width was greater in brachyfacial than in mesofacial subjects...

Avaliação da inclinação axial dos dentes posteriores e sua respectiva morfologia alveolar nos diferentes padrões faciais: uma visão por meio da tomografia computadorizada de feixe cônico / Evaluation of the axial inclination of posterior teeth and their respective alveolar morphology in different facial patterns: a vision by cone beam computed tomography

O objetivo deste estudo foi comparar, por meio de tomografia computadorizada de feixe cônico, a inclinação axial dos dentes posteriores e a morfologia óssea alveolar mandibular entre indivíduos com diferentes padrões faciais. Para isso, foram utilizadas 58 tomografias de indivíduos maiores de 14 anos de idade não tratados ortodonticamente. Os indivíduos foram divididos em 3 grupos de acordo com o padrão facial avaliado pelo índice VERT de Ricketts: Grupo 1: composto por 18 indivíduos com padrão braquifacial, com idade média de 21,58 anos (d.p.=7,43); Grupo 2: composto por 23 indivíduos com padrão mesofacial, com idade média de 19,14 anos (d.p.=5,19); e Grupo 3: composto por 17 indivíduos com padrão dolicofacial, com idade média de 19,09 anos (d.p.=6,89). Foi realizada uma avaliação quantitativa das tábuas ósseas vestibular e lingual dos dentes pósteroinferiores, em tomografias de feixe cônico. As medidas utilizadas foram: altura do osso mandibular vestibular e lingual, largura mandibular cervical e média, inclinação mandibular, inclinação da face vestibular, largura do molar, angulação do molar e ângulo dente/osso. A comparação intergrupos foi realizada com a utilização do teste ANOVA a um critério de seleção e teste de Tukey quando necessário. Para verificar se existe correlação entre o padrão facial e as variáveis estudadas foi utilizado o teste de correlação de Pearson. Os resultados demonstraram que os indivíduos braquifaciais apresentaram uma menor inclinação mandibular quando comparados aos indivíduos mesofaciais e dolicofaciais. Houve diferença significante da altura mandibular vestibular entre os três grupos avaliados, sendo que esta foi menor no grupo braquifacial, intermediária no grupo mesofacial e maior no grupo dolicofacial. A altura mandibular lingual foi menor no grupo braquifacial em comparação aos grupos mesofacial e dolicofacial. A largura mandibular média foi maior nos indivíduos braquifaciais em relação aos mesofaciais.

The aim of this study was to compare, with cone beam computed tomography, the axial inclination of posterior teeth and mandibular alveolar bone morphology among individuals with different facial patterns. For this, 58 CT scans of untreated individuals orthodontically aged more than 14 years were used. The subjects were divided into 3 groups according to the facial pattern evaluated by the VERT index by Ricketts: Group 1 comprised 18 individuals with brachyfacial pattern, with a mean age of 21.58 years (s.d.=7.43); Group 2 comprised 23 individuals with mesofacial pattern, with a mean age of 19.14 years (s.d.=5.19); and Group 3 comprised 17 individuals with dolichofacial pattern, with a mean age of 19.09 years (s.d.=6.89). A quantitative assessment of the buccal and lingual bone plates of the mandibular posterior teeth were made in cone beam CT scans. The variables measured were: buccal and lingual mandibular height, cervical and middle mandibular width, mandibular inclination, inclination of the buccal surface, molar width, molar angle and tooth/bone angle. The intergroup comparison was performed by one-way ANOVA and Tukey test when necessary. To check whether there is a correlation between facial pattern and the variables studied, the Pearson correlation test was used. The results showed that the brachyfacial subjects had a smaller mandibular angle when compared to mesofacial and dolichofacial individuals. There was significant difference in the buccal mandibular height between the three groups, and this was smaller in the brachyfacial group, intermediate in the mesofacial group and larger in the dolichofacial group. Lingual mandibular height was smaller in brachyfacial group when compared to mesofacial and dolichofacial groups. The mean mandibular width was greater in brachyfacial than in mesofacial subjects.

Padronização de um método para mensuração das tábuas ósseas vestibular e lingual dos maxilares na Tomografia Computadorizada de Feixe Cônico (Cone Beam) / Method standardization of buccal and palatal arch bone plate measurement using Cone Beam Computed Tomography

INTRODUÇÃO: a espessura das tábuas ósseas que recobrem os dentes por vestibular e lingual constitui um dos fatores limitantes da movimentação dentária. O avanço tecnológico em Imaginologia permitiu avaliar detalhadamente essas regiões anatômicas por meio da utilização da tomografia computadorizada de feixe cônico (TCFC). OBJETIVO: descrever e padronizar, pormenorizadamente, um método para mensuração das tábuas ósseas vestibular e lingual dos maxilares nas imagens de tomografia computadorizada de feixe cônico. METODOLOGIA: a padronização digital da posição da imagem da face deve constituir o primeiro passo antes da seleção dos cortes de TCFC. Dois cortes axiais de cada maxilar foram empregados para a mensuração da espessura do osso alveolar vestibular e lingual. Utilizou-se como referência a junção cemento-esmalte dos primeiros molares permanentes, tanto na arcada superior quanto na inferior. RESULTADOS: cortes axiais paralelos ao plano palatino foram indicados para avaliação quantitativa do osso alveolar na maxila. Na arcada inferior, os cortes axiais devem ser paralelos ao plano oclusal funcional. CONCLUSÃO: o método descrito apresenta reprodutibilidade para utilização em pesquisas, assim como para a avaliação clínica das repercussões periodontais da movimentação dentária, ao permitir a comparação de imagens pré e pós-tratamento.

INTRODUCTION: The thickness of the buccal and lingual bone plates constitutes one of the limiting factors of the orthodontic movement. The imaging technology has permitted the evaluation of this anatomical region, by means of cone beam computed tomography. PURPOSE: To describe and standardize, in details, a method for measuring the buccal and lingual bone plate thickness in CBCT images. METHODOLOGY: Digital standardization of face image should constitute the first step before the selection of CBCT slices. Two axial sections of each jaw were used for measuring the thickness of buccal and lingual bone plates. The cemento-enamel junction of the first permanent molars was used as a reference, both in the upper and lower arches. RESULTS: Axial sections parallel to the palatine plane were recommended for quantitative evaluation of the alveolar bone plate in the maxilla. In the mandibular arch, the axial sections should be parallel to the functional occlusal plane. CONCLUSION: The method described shows reproducibility for evaluating the periodontal effects of tooth movement for clinical or researching purposes, permitting the comparison between pre and post-treatment images.