Measurement of buccolingual inclination of posterior teeth and the curve of Wilson in patients with different sagittal skeletal patterns using cone-beam computed tomography / 口腔疾病防治

Objective@# To study the buccolingual inclination of posterior premolars and molars and the curve of Wilson in patients with different sagittal skeletal patterns, to explore the compensation mechanism of horizontal inclination of posterior teeth in patients with different sagittal skeletal patterns and to provide a reference for the control of posterior tooth inclination in the treatment of bone malocclusion.@*Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. Ninety CBCT scans of adults and ninety scans of adolescents before orthodontic treatment were evaluated in this cross-sectional study. There were 30 skeletal Class I, Class Ⅱ, and Class Ⅲ patients in the adult group and adolescent group. The inclination angles of posterior teeth and the curve of Wilson of first and second molars were measured, and data were analyzed between adolescents and adults with different sagittal skeletal patterns.@*Results @#Compared with skeletal Class Ⅰ adult patients, the upper posterior molar inclination of skeletal Class Ⅱ patients was significantly lower, and the lower posterior molar inclination was significantly higher. Compared with skeletal ClassⅠ adult patients, the upper posterior molar inclination of skeletal Class Ⅲ adult patients was higher, and the lower posterior molar inclination was significantly lower. The Wilson curve of the second molar in skeletal Class Ⅱ adult patients was significantly higher than that in the other groups. Compared with skeletal ClassⅠ adolescent patients, skeletal Class Ⅲ adolescent patients had a significantly higher upper posterior molar inclination; however, no difference was found between the inclination of the posterior teeth between skeletal Class Ⅰ, Class Ⅱ and Class Ⅲ adolescent patients. Comparing adolescent and adult samples, in skeletal Class Ⅱ patients, adults showed more lingual inclination than adolescents in the upper posterior teeth and less lingual inclination in the lower posterior teeth except for the mandibular first molar. Comparing adolescent and adult samples, in skeletal Class Ⅲ patients, adults showed more lingual inclination than adolescents in the lower posterior teeth except for the mandibular second molars and showed no difference in the upper posterior teeth.@*Conclusions@#The inclination of the posterior teeth and the curve of Wilson show significant differences between the three sagittal skeletal patterns. Compared with those of skeletal Class Ⅰ patients, the posterior teeth of skeletal Class Ⅱ patients show more lingual inclination in the upper arch and less lingual inclination in the lower arch. Meanwhile, posterior teeth of skeletal Class Ⅲ patients show more lingual inclination in the lower arch and maintain the inclination in the upper arch.

Comparison of hyoid bone positions among patients with different sagittal skeletal malocclusions / 口腔疾病防治

Objective@# To compare the hyoid bone position among patients with different sagittal skeletal malocclusions to provide a reference for clinicians to formulate treatment plans.@*Methods@#Lateral cephalograms of 284 orthodontic patients were selected. According to ANB angles, the types of skeletal malocclusion of patients were determined as follows: Class Ⅰ (1° ≤ ANB ≤ 5°), Class Ⅱ (ANB>5°) and Class Ⅲ (ANB<1°). Ten parameters were used to determine hyoid positions. After comparing the hyoid positions of the three groups, stratified analyses based on sex and age were conducted. @*Results @# No significant differences in demographic and vertical facial type features among skeletal Classes Ⅰ, Ⅱ and Ⅲ patients were observed (P>0.05). The angle between the Gonion-hyoid point line and the hyoid point-Menton line (Go-Hy-Me) of Class Ⅱ patients was significantly smaller than that of Class Ⅰ patients, and the angle between the most anterior and inferior point of the third cervical vertebra-hyoid point line and the hyoid point-Sella line (C3-Hy-S) of Class Ⅲ patients was smaller than that of Class I patients (P<0.05). Age-stratified analysis showed that in the juvenile group, the C3-Hy-S of Class Ⅲ patients was significantly smaller than that of Class Ⅰ patients in males and females (P<0.05). In the adult female group, the Go-Hy-Me of Class Ⅱ patients was significantly smaller, and the distance from the hyoid point to the mandibular plane (Hy-MP) was larger than that noted in Class Ⅰ patients (P<0.05); no significant difference in hyoid position between male Class Ⅱ and I patients was observed (P>0.05).@*Conclusions@#Compared with Class Ⅰ patients, the hyoid bone of Class Ⅱ patients in adult females was farther away from the mandible and that of Class Ⅲ patients in juveniles was farther away from the cervical vertebra and posterior cranial base.

Comparison between cephalometric measurements using digital manual and web-based artificial intelligence cephalometric tracing software

ABSTRACT Objective: The aim of this study was to compare the measurements performed with digital manual (DM) cephalometric analysis and automatic cephalometric analysis obtained from an online artificial intelligence (AI) platform, according to different sagittal skeletal malocclusions. Methods: Cephalometric radiographs of 105 randomly selected individuals (mean age: 17.25 ± 1.87 years) were included in this study. Dolphin Imaging software was used for DM cephalometric analysis, and the WebCeph platform was used for AI-based cephalometric analysis. In total, 10 linear and 12 angular measurements were evaluated. The paired t-test, one-way ANOVA test, and intraclass correlation coefficient tests were used to evaluate the differences between the two methods. The level of statistical significance was set at p< 0.05. Results: Except for SNB, NPog, U1.SN, U1.NA, L1-APog, I/I, and LLE parameters, all other parameters presented significant differences between the two methods (p< 0.05). While there was no difference (p> 0.05) in both SNA and SNB measurements between the two methods in the Class I malocclusion group, there was a difference between both methods in the Class II malocclusion group. Meanwhile, only the SNA in the Class III malocclusion group was different (p< 0.05). The ANB angle differed significantly in all three malocclusion groups. For both methods, all parameters except CoA and CoGn were found to have good correlation. Conclusion: Although significant differences were detected in some measurements between the two cephalometric analysis methods, not all differences were clinically significant. The AI-based cephalometric analysis method needs to be developed for more specific malocclusions.

RESUMO Objetivo: Comparar as medidas realizadas usando análise cefalométrica digital-manual (DM) e análise cefalométrica automatizada por meio de uma plataforma online de inteligência artificial (IA), segundo as diferentes más oclusões esqueléticas sagitais. Métodos: Foram incluídas radiografias cefalométricas de 105 indivíduos selecionados aleatoriamente (idade média: 17,25 ± 1,87 anos). O software Dolphin Imaging foi utilizado para análise cefalométrica DM, e a plataforma WebCeph foi utilizada para análise cefalométrica baseada em IA. No total, foram avaliadas 10 medidas lineares e 12 angulares. O testet pareado, a ANOVA de uma via e o coeficiente de correlação intraclasse foram utilizados para avaliar as diferenças entre os dois métodos. O nível de significância foi estabelecido em p<0,05. Resultados: Com exceção dos parâmetros SNB, NPog, U1.SN, U1.NA, L1-APog, I/I e LIE, todos os outros parâmetros apresentaram valores significativamente diferentes entre os dois métodos (p<0,05). Enquanto não foi encontrada diferença (p>0,05) nas medidas SNA e SNB entre os dois métodos no grupo má oclusão de Classe I, foi encontrada diferença entre os métodos no grupo má oclusão de Classe II. Entretanto, no grupo má oclusão de Classe III somente o SNA foi diferente (p<0,05). O ângulo ANB diferiu significativamente em todos os três grupos de más oclusões. Foi encontrada boa correlação entre os dois métodos para todos os parâmetros, exceto para CoA e CoGn. Conclusão: Embora para algumas medidas tenham sido detectadas diferenças significativas entre os dois métodos de análise cefalométrica, nem todas as diferenças foram clinicamente significativas. O método de análise cefalométrica baseado em IA precisa ser aperfeiçoado, com maior especificidade para cada má oclusão.

Clinical analysis of skeletal malocclusion, axial inclination in patients with short root anomaly of the maxillary central incisors / 口腔疾病防治

Objective @#To investigate the prevalence and distribution of skeletal malocclusion and axial inclination of the maxillary central incisors in short root anomaly (SRA) patients in Kunming city, to provide some reference and guidance for SRA patients′ clinical diagnosis and treatment and prevention in SRA patients. @*Methods@#A total of 1 000 cases were randomly selected from the CBCT database of patients admitted to the author′s hospital from January 2011 to July 2019, and a retrospective analysis was performed. A total of 27 patients with SRA were diagnosed (SRA group).The control group, consisted of 100 randomly selected patients from non-SRA patients. According to the clinical data and cephalometric data, skeletal malocclusion was divided into three subgroups: Class I skeletal malocclusion, Class II skeletal malocclusion and Class Ⅲ skeletal malocclusion. Additionally, the axial inclination of the central incisors was divided into three subgroups: the lingual inclination group, labial inclination group and normal inclination group. The two groups each according to sex, skeletal malocclusion and types of axial inclination of the maxillary central incisors were discussed. @*Results @# The prevalence rate of SRA in the selected population was 2.7%, and the prevalence of SRA in females was 3.67% (21/572) , which was higher than that in males by 1.4% (6/428), and was significantly different between sexes (χ2=4.562, P=0.033). There was a significant difference between SRA patients and control group in terms of skeletal malocclusion (χ2=8.710, P=0.013). Class Ⅲ skeletal malocclusion was the main type of skeletal malocclusion in SRA. There was a significant difference between SRA patients and control group in terms of the axial inclination of the maxillary central incisors (χ2=16.75,P<0.001). Lingual inclination of the maxillary central incisors was the main type of axial inclination of the maxillary central incisors in SRA. @*Conclusion@#There is a certain correlation between class Ⅲ skeletal malocclusion and lingual inclination of the maxillary central incisors and SRA, and the root-crown ratio and root shape of these patients should be evaluated before orthodontics are implemented.

Cervical vertebral anomalies in skeletal malocclusions: A cross-sectional study on orthodontic patients at the Aga Khan University Hospital, Pakistan.

Introduction: Morphological deviations of the cervical vertebral column have been described in relation to craniofacial aberrations and syndromes. Furthermore, it has recently been shown that abnormal morphology of upper cervical vertebrae is associated with malformation of the jaws and occlusion. Accordingly, it is relevant to focus on similar associations in patients with skeletal malocclusions. Therefore, the objectives of this study are to: • Identify the anomalies of the cervical column in patients with skeletal malocclusions • Determine the association between cervical vertebral anomalies and skeletal malocclusions. Materials and Methods: This cross‑sectional study was conducted on a total of 90 subjects at the Aga Khan University Hospital, Pakistan. The inclusion criteria were: (1) Pakistani origin; (2) standardized pretreatment profile radiograph with first six cervical vertebrae visible; and (3) accessibility of the second‑profile radiograph (mid‑ or posttreatment). The exclusion criteria were: (1) A prior history of orthodontic treatment; (2) any craniofacial anomaly; and (3) systemic muscle or joint disorder. Lateral cephalograms of all subjects (n = 90) were traced by the principal investigator and sagittal jaw relationship was assessed. A total of 30 subjects each with skeletal Class I, Class II, and Class III malocclusions were selected and the cervical vertebral anomalies were observed on their cephalometric radiographs. The frequencies of cervical vertebral anomalies according to skeletal malocclusion categories and gender were analyzed with the Chi‑square test, whereas association of cervical vertebral anomalies with skeletal malocclusions was assessed with logistic regression analysis. The level of significance (P ≤ 0.05) was used for the statistical tests. Results: Most common anomaly observed in the three groups was fusion between C2 and C3 (P = 0.006). This anomaly was found in 20% of subjects with skeletal Class I, 50% of subjects with skeletal Class II and 53.3% with skeletal Class III malocclusions. The highest frequencies of partial cleft at the level of C1 and occipitalization were observed in subjects with skeletal Class II and III malocclusions, respectively. However, none of the subjects showed fusion between C1 and C2 or dehiscence. No statistically significant gender difference was found in the occurrence of morphological deviations of the cervical column. The association of cervical vertebral anomaly was found to be the highest with skeletal Class III and lowest with skeletal Class I malocclusions. Conclusion: Fusion between C2 and C3 seems to be the most commonly occurring anomaly. This anomaly seems to be more often associated with skeletal Class III than skeletal Class I or Class II malocclusions.

Self-evaluation of dentofacial esthetics in skeletal malocclusion patients / 中华医学美学美容杂志

Objective To investigate the difference between the self-evaluation of patients with dental and facial esthetics in skeletal malocclusion and normal persons.Methods The subjects were divided into three groups:62 patients with skeletal Class Ⅱ,84 patients with skeletal Class Ⅲ,as well as 130 persons in control group.There was no obvious difference in gender and age among the three groups.Happiness with dental and facial appearance was assessed using questionnaires.Analysis of variance,linear regression and logistic regression were used for statistical analysis.Results Skeletal malocclusion patients were less happy with their dental appearance than control group.Class Ⅱ patients and women had lower happiness scores for their dental appearance.Among skeletal malocclusion patients,the shape (44.5 ％) and prominence of their teeth (17.8 ％) were the most frequent causes of concern.Older subjects,women,and skeletal malocclusion patients were less happy with their facial appearance.Most of them were dissatisfied with the facial appearance focused on the chin (53 ％),facial contours (37 ％),and the position of the teeth when smiling (33 ％).A greater proportion of Class Ⅲ subjects than Class Ⅱ subjects wished to change their appearance.Conclusions The findings indicate that women and skeletal malocclusion patients have lower levels of happiness with their dentofacial appearance.Although Class Ⅱ patients exhibit the lowest levels of happiness with their dental appearance,there is some evidence that concerns and awareness about their facial profile are more pronounced among the Class Ⅲ patients.

Cone Beam Volumetric Tomography (CBVT)- In Orthodontics.

CBVT is being used in Orthodontics due its ability to obtain 3- dimensional representation of craniofacial structures. It represents a highly precise image of the anatomic structures and clearly depicts the location of various anatomic structures. The Cone beam volumetric tomography(CBVT) can be considered as an Essential Diagnostic Aid in patients having skeletal asymmetry and severe skeletal malocclusions undergoing Orthognathic surgeries.