Afonso Pinhão Ferreira

Validity of 2D lateral cephalometry in orthodontics: a systematic review

Lateral cephalometric radiography is commonly used as a standard tool in orthodontic assessment and treatment planning. The aim of this study was to evaluate the available scientific literature and existing evidence for the validation of using lateral cephalometric imaging for orthodontic treatment planning. The secondary objective was to determine the accuracy and reliability of this technique. We did not attempt to evaluate the value of this radiographic technique for other purposes. A literature search was performed using specific keywords on electronic databases: Ovid MEDLINE, Scopus and Web of Science. Two reviewers selected relevant articles, corresponding to predetermined inclusion criteria. The electronic search was followed by a hand search of the reference lists of relevant papers. Two reviewers assessed the level of evidence of relevant publications as high, moderate or low. Based on this, the evidence grade for diagnostic efficacy was rated as strong, moderately strong, limited or insufficient. The initial search revealed 784 articles listed in MEDLINE (Ovid), 1,034 in Scopus and 264 articles in the Web of Science. Only 17 articles met the inclusion criteria and were selected for qualitative synthesis. Results showed seven studies on the role of cephalometry in orthodontic treatment planning, eight concerning cephalometric measurements and landmark identification and two on cephalometric analysis. It is surprising that, notwithstanding the 968 articles published in peer-reviewed journals, scientific evidence on the usefulness of this radiographic technique in orthodontics is still lacking, with contradictory results. More rigorous research on a larger study population should be performed to achieve full evidence on this topic.

Different manifestations of class II division 2 incisor retroclination and their association with dental anomalies.

Objective To investigate whether there is an association between dental developmental anomalies (DDAs) and different manifestations of class II division 2 (CII/2) malocclusion incisor retroclination. Design Retrospective comparative study. Setting Private orthodontic practice in the regions of Lisbon and Porto, Portugal. Subjects and methods The sample comprised 115 CII/2 malocclusions distributed into two groups on the basis of incisor retroclination: Group I composed of 48 CII/2 with retroclination exclusively of both maxillary central incisors; Group II composed of 67 CII/2 with retroclination of all four maxillary incisors. Using the initial orthodontic records, it was determined for each patient the presence of the following DDAs: tooth impaction, tooth agenesis, maxillary lateral incisor microdontia, tooth transpositions and supernumerary teeth. Results Fifty-five per cent of patients were diagnosed with at least one of the DDAs studied. In the total sample the prevalence rates were: 20.0% of palatal maxillary canine impaction, 27.4% of third molar agenesis, and 15.7% of maxillary lateral incisor microdontia. No patient exhibited any transposition or supernumerary teeth. The distribution of the DDAs studied by groups revealed a strong association of palatal canine impaction, tooth agenesis and maxillary lateral incisor microdontia with Group II but not with Group I. Conclusion The association of DDAs with CII/2 malocclusion is not common to all types of maxillary incisor retroclination, suggesting different etiologic factors among the different manifestations of CII/2 incisor retroclination.

Cephalometric landmark variability among orthodontists and dentomaxillofacial radiologists: a comparative study

Purpose The aim this study was to compare the accuracy of orthodontists and dentomaxillofacial radiologists in identifying 17 commonly used cephalometric landmarks, and to determine the extent of variability associated with each of those landmarks. Materials and Methods Twenty digital lateral cephalometric radiographs were evaluated by two groups of dental specialists, and 17 cephalometric landmarks were identified. The x and y coordinates of each landmark were recorded. The mean value for each landmark was considered the best estimate and used as the standard. Variation in measurements of the distance between landmarks and measurements of the angles associated with certain landmarks was also assessed by a subset of two observers, and intraobserver and interobserver agreement were evaluated. Results Intraclass correlation coefficients were excellent for intraobserver agreement, but only good for interobserver agreement. The least reliable landmark for orthodontists was the gnathion (Gn) point (standard deviation [SD], 5.92 mm), while the orbitale (Or) was the least reliable landmark (SD, 4.41 mm) for dentomaxillofacial radiologists. Furthermore, the condylion (Co)-Gn plane was the least consistent (SD, 4.43 mm). Conclusion We established that some landmarks were not as reproducible as others, both horizontally and vertically. The most consistently identified landmark in both groups was the lower incisor border, while the least reliable points were Co, Gn, Or, and the anterior nasal spine. Overall, a lower level of reproducibility in the identification of cephalometric landmarks was observed among orthodontists.

Comparison of condylar displacement between three biotypological facial groups by using mounted models and a mandibular position indicator.

Objective Facial-type-associated variations in diagnostic features have several implications in orthodontics. For example, in hyperdivergent craniofacial types, growth imbalances are compensated by displacement of the condyle. When diagnosis and treatment planning involves centric relation (CR), detailed knowledge of the condylar position is desirable. The present study aimed to measure condylar displacement (CD) between CR and maximum intercuspation in three facial types of an asymptomatic orthodontic population. Methods The study was conducted in 108 patients classified into three groups of 36 individuals each (27 women and 9 men; mean age, 20.5 years), based on the following facial patterns: hyperdivergent, hypodivergent, and intermediate. To quantify CD along the horizontal and vertical axes, the condylar position was analyzed using mounted casts on a semi-adjustable articulator and a mandibular position indicator. The Student t-test was used to compare CD between the groups. Results Vertical displacement was found to be significantly different between the hyperdivergent and hypodivergent groups (p < 0.0002) and between the hyperdivergent and intermediate groups (p < 0.0006). The differences in horizontal displacement were not significant between the groups. In each group, vertical CD was more evident than horizontal displacement was. Conclusions All facial types, especially the hyperdivergent type, carried a significantly high risk of CD. Therefore, the possibility of CD should be carefully evaluated and considered in the assessment of all orthodontic cases in order to accurately assess jaw relationships and avoid possible misdiagnosis.

How to Achieve Facial Balance by Mandibular Contouring Ostectomy in Hemimandibular Hyperplasia

Hemimandibular hyperplasia is a rare type of condylar hyperplasia which leads to facial asymmetry. Its surgical correction may be challenging since it usually requires complex mandibular osteotomies. Mandibular inferior border ostectomy is poorly described in the literature. The aim of this report is to present a new surgical technique guided by a customized surgical splint manufactured using computer-aided design/computer-aided manufacturing technology. Very good aesthetic results are achieved as it is very precise.

Perspectiva Ortodôntica da Cirurgia do Mento

Resumo A forma, a dimensao e a posicao do mento constituem factores que contribuem de forma significativa para a harmonia facial. Dos varios procedimentos que possibilitam a correccao do mento, destaca-se, pelo seu leque de possibilidades correctivas, a osteotomia do bordo inferior da mandibula, geralmente denominada de mentoplastia. Neste artigo abordam-se alguns aspectos clinicos e cefalometricos da planificacao da cirurgia do mento, as tecnicas cirurgicas mais utilizadas e as respectivas indicacoes.

Sella landmark variability and its effect on the Angles SNA and SNB: a comparative study

Objective: To determine intra- and inter-observer precision in Sella (S), Nasion (N), point A and B identification. Additionally, to determine how it can interfere with angular measurements of SNA and SNB by orthodontists and dentomaxillofacial radiologists. Methods: Twenty digital lateral cephalometric radiographs were evaluated by five orthodontists and five dentomaxillofacial radiologists. Results: Differences in linear and angular measuremts were assessed. Intra- and inter-observer agreement was evaluated. Intra- and inter-observer reproducibility of the horizontal and vertical components of the S landmark identification (ICC: 0.75/0.90). Orthodontists tended to produce larger SNA (-0.18o), while SNB angle had a tendency to be smaller (0.55o). In general, SNA angle was smaller (DMFRs: -0.308o and orthodontists: -0.092o), and SNB presented with larger values (DMFR: 0.078o and orthodontists: -0.074o). Conclusion: Identification of the Sella landmark revealed a better agreement amongst dentomaxillofacial radiologists. Orthodontists, however, showed a larger variability in S identification and, consequently, the SNA and SNB angles drifted significantly.

Effect of activation and preactivation on the mechanical behavior and neutral position of stainless steel and beta-titanium T-loops

Objective To quantify, for each activation, the effect of preactivations of differing distribution and intensity on the neutral position of T-loops (7-mm height), specifically the horizontal force, moment to force (M/F) ratio, and load to deflection ratio. Methods A total 100 loops measuring 0.017 × 0.025 inches in cross-section were divided into two groups (n = 50 each) according to composition, either stainless steel or beta-titanium. The two groups were further divided into five subgroups, 10 loops each, corresponding to the five preactivations tested: preactivations with occlusal distribution (0°, 20°, and 40°), gingival distribution (20°), and occlusal-gingival distribution (40°). The loops were subjected to a total activation of 6-mm with 0.5-mm iterations. Statistical analysis was performed using comprised ANOVA and Bonferoni multiple comparison tests, with a significance level of 5%. Results The location and intensity of preactivation influenced the force intensity. For the M/F ratio, the highest value achieved without preactivation was lower than the height of the loop. Without preactivation, the M/F ratio increased with activation, while the opposite effect was observed with preactivation. The increase in the M/F ratio was greater when the preactivation distribution was partially or fully gingival. Conclusions Depending on the preactivation distribution, displacement of uprights is higher or lower than the activation, which is a factor to consider in clinical practice.

Diagnostic model of anterior open bite--a new way to predict skeletal type: a cross-sectional study.

INTRODUCTION The aim of this study was to determine a differential diagnostic model for anterior open bite (AOB) in children in order to predict evolution with growth in cases of skeletal or dysfunctional dysplasia. MATERIAL AND METHODS The sample was composed of 128 subjects divided into 2 groups according to overbite values: a control group with normal occlusion and 2.5 ± 1mm overbite, and an AOB group with a negative overbite. Measurements of hyoid bone position, gonial angle, SN/Go-Gn, FMA, height of alveolar processes, upper lip height, height of the anterior nasal spine to stomion superior, upper incisor and menton, antegonial notch, symphysis anatomy, condyle anatomy, convexity, facial axis, lower oropharyngeal area and curve of Spee were obtained for all subjects, based on lateral cephalometric radiographs and lateral photos. All data were analyzed, and multivariate logistic regression was applied. The area under the receiver operating characteristic (ROC) curve was calculated for the models obtained by logistic regression, in order to evaluate them. Statistical analysis was performed in IBM(®) SPSS(®) Statistics version 21.0. RESULTS The results demonstrated that the AOB model was capable of predicting skeletal anterior open bite with an accuracy of 93%. The seven variables selected were: lower face height (LFH), height of mandibular alveolar process, antegonial notch, symphysis direction, symphysis thickness, gonial angle and facial axis. CONCLUSIONS Measurements of facial morphology made it possible to construct a model able to differentiate, with a small margin of error, between the two distinct forms of AOB: skeletal and dysfunctional.

I-46. REPRODUTIBILIDADE DE DIFERENTES INSTRUMENTOS DE MEDIÇÃO NA ANÁLISE DE BOLTON.

analisados, 2 foram excluidos e a amostra de validacao passou a ser de 58. Posteriormente realizou-se uma analise estatistica, utilizando os programas MatLab e Excel, obtendose as diferencas entre os valores previstos, segundo os varios metodos, e os valores reais observados nos modelos. Resultados: O metodo de Moyers pelo percentil 50 apresenta uma percentagem de erro superior a 1mm de 29%, o de Tanaka e Johnston de 38% e o de Moyers pelo percentil 75 de 45%. O metodo de Moyers pelo percentil 75 e o de Tanaka e Johnston subestimam o valor real em mais de 1mm em cerca de 3% da amostra. Este ultimo metodo sobrestima por mais de 1mm em 35% dos casos e o metodo de Moyers pelo percentil 75 em 42%. O metodo de Moyers pelo percentil 50 apresenta erros superiores a 1mm de 12% na subestimacao e 17% na sobrestimacao. Conclusoes: Deste trabalho pode concluir-se que a analise da denticao mista atraves do metodo de Moyers pelo percentil 50 e a que apresenta menor frequencia de erros superiores a 1mm. Este metodo tambem apresenta uma distribuicao mais equilibrada dos erros superiores a 1mm na subestimacao e na sobrestimacao. Conclui-se que, de entre os metodos analisados, o de Moyers no percentil 50, e aquele que com mais fiabilidade pode ser aplicado na populacao portuguesa.