Avaliação tridimensional da via aérea superior de pacientes com apneia obstrutiva do sono que utilizaram aparelho de avanço mandibular

Os objetivos deste estudo foram avaliar o efeito do aparelho de avanço mandibular (Twin block - TB) no volume das vias aéreas superiores, por meio de tomografia computadorizada cone beam (CBCT); analisar, por meio da polissonografia, as mudanças no índice de apneia e hipopneia (IAH) e índice de apneia por hora de sono (IA), saturação de oxi-hemoglobina e eficiência do sono; e correlacionar o volume na CBCT e as polissonografias. Dezesseis pacientes portadores de apneia obstrutiva do sono, idade média de 47,06 anos, participaram deste estudo prospectivo, com acompanhamento médio de 7 meses. Foram feitas polissonografias iniciais (T1) e de acompanhamento (T2) com o TB em posição, e CBCT sem e com TB em posição. A segmentação e obtenção dos volumes das vias aéreas superiores foram realizadas e utilizados os testes t de Student pareado, de Wilcoxon e o índice de correlação de Spearman, com 5% de significância. Os resultados das polissonografias mostraram diferenças estatisticamente significativas entre T1 e T2 apenas para IAH (p<0,05). Houve aumento do volume da via aérea superior com TB quando comparado com o volume sem TB (p<0,05). Foi possível estabelecer-se correlação positiva entre volume da via aérea superior sem TB e IAH e IA em T1 (p<0,05), mas não houve correlação entre o volume da via aérea com TB e índices polissonográficos em T2. Pode-se concluir que, houve aumento de volume da via aérea superior com o TB e houve redução do IAH em T2 porém, sem correlação entre estes dados.

Mandibular morphometric variation among Chinese cercopithecoids and the unique structure of the snub-nosed monkey (Rhinopithecus) mandible

In order to understand how mandibular structure differs among the Chinese cercopithecoids (Rhinopithecus, Trachypithecus and Macaca), particularly the uniqueness of the snub-nosed monkeys (Rhinopithecus), we analysed ten mandibular measurements by principal components analysis (PCA), and examined scaling patterns. The results provided by the PCA illustrated differences due to size among the cercopithecoids and the relationship between colobines (Trachypithecus and Rhinopithecus) and cercopithecines, in which macaques (Macaca) are included. Allometric analysis indicated that, biomechanically, there is not a marked difference between macaques and leaf-eating monkeys. This may be associated with the fact that both share some similar ecology and niches in south and southwest China. The snub-nosed monkeys exhibit a significantly more robust mandible, evident in the symphysis, corpus, condyle, and masticatory momentum arm. This supports the hypothesis, based on the study of dental structure, that Rhinopithecus is a unique group in Asian Old World monkeys (OWMs) and has developed some unique characteristics in order to adapt to the tough food available in the severe cold climate of the Plateaux of Qinghai-Tibet, Yun-Gui and Qingling in China.

MANDIBULAR MORPHOMETRICS AMONG MACAQUES - THE CASE OF MACACCA-THIBETANA

Recent field studies suggest that Macaca thibetana, a large endemic Chinese macaque, may be quite folivorous, distinguishing it from most other macaque species, which tend to be primarily frugivorous. To understand how this diet affects its masticatory system, we conducted a comparative morphometric study of mandibular dimensions. We took linear measurements from male and female mandibles of this species as well as four other macaques-M. fascicularis, M. nemestrina, M. arctoides, and M. assamensis-and four species of Presbytis-P. obscura, P. rubicunda, P. cristata, and P. phayrei-and subjected to them to a variety of analyses. Based on analyses of variances and discriminant analyses on each sex individually, the mandible of M. thibetana corresponds to expected patterns for folivorous primates with respect to its wide condyles and thick corpora: However, the height of the corpus and symphysis are lower, and the anteroposterior length of the condyle is longer than predicted for a folivore. In addition to interpretations specifically relating to M. thibetana, we also discuss the functional morphology of the other species in light of what is published about their diets.

Mandibular variation among Chinese macaques

In order to clarify the degree to which mandibular variation among Chinese macaques results from functional adaptation and phylogenetic inertia, 13 mandibular variables were analyzed by bivariate and multivariate techniques. The results indicate, not surprisingly, that the main differences in the mandible are associated with size. The study further implies that the variation between species is not closely associated with differences in functional adaptation even though the dietary and related differences are large compared to the situation in other macaques. The great variety in diet and related factors among Chinese macaques may not have yet resulted in a significant variation in the mandible. This may be because their radiation in Asia, though involving considerably greater differences in habitat, climate, and so on, has occurred more recently than for other macaque species in Southeast Asia. Mandibular variation between these species, therefore, is likely to be more closely tied to their immediate prior phylogenetic history. For example, the two stump-tailed macaques are closely similar and are also closely similar to the Assam species. Function in the mandible in these species is quite different. The results, therefore, seem to support the hypothesis that these three macaque species should be placed in a single species-group (sinica) as proposed by Delson [1980], Pan [1998], and Pan et al. [1998]. (C) 2002 Wiley-Liss, Inc.

Mandibular Manipulation for the Treatment of Temporomandibular Disorder

The aim of this study was to conduct a systematic review to identify the randomized clinical studies that had investigated the following research question: Is the mandibular manipulation technique an effective and safe technique for the treatment of the temporomandibular joint disk displacement without reduction? the systematic search was conducted in the electronic databases: PubMed (Medical Publications), LILACS (Latin American and Caribbean Literature in Health Sciences), EMBASE (Excerpta Medica Database), PEDro (Physiotherapy Evidence Database), BBO (Brazilian Library of Odontology), CENTRAL (Library Cochrane), and SciELO (Scientific Electronic Library Online). the abstracts of presentations in physical therapy meetings were manually selected, and the articles of the ones that meet the requirements were investigated. No language restrictions were considered. Only randomized and controlled clinical studies were included. Two studies of medium quality fulfilled all the inclusion criteria. There is no sufficient evidence to support the effectiveness of the mandibular manipulation therapy, and therefore its use remains questionable. Being minimally invasive, this therapy is attractive as an initial approach, especially considering the cost of the alternative approaches. the analysis of the results suggests that additional high-quality randomized clinical trials are necessary on the topic, and they should focus on methods for data randomization and allocation, on clearly defined outcomes, on a priori calculated sample size, and on an adequate follow-up strategy.

A cephalometric study of class II malocclusions treated with mandibular surgery

INTRODUCTION:

Class II malocclusion is often associated with retrognathic mandible. Some of these problems require surgical correction. The purposes of this study were to investigate treatment outcomes in patients with Class II malocclusions whose treatment included mandibular advancement surgery and to identify predictors of good outcomes.
METHODS:

Pretreatment and posttreatment cephalometric radiographs of 90 patients treated with mandibular advancement surgery by 57 consultant orthodontists in the United Kingdom before September 1998 were digitized, and cephalometric landmarks were identified. Paired samples t tests were used to compare the pretreatment and posttreatment cephalometric values for each patient. For each cephalometric variable, the proportion of patients falling within the ideal range was identified. Multiple logistic regression analysis was performed to identify predictors of achieving ideal range outcomes for the key skeletal (ANB and SNB angles), dental (overjet and overbite), and soft-tissue (Holdaway angle) measurements.
RESULTS:

An overjet within the ideal range of 1 to 4 mm was achieved in 72% of patients and was more likely with larger initial ANB angles. Horizontal correction of the incisor relationship was achieved by a combination of 75% skeletal movement and 25% dentoalveolar change. An ideal posttreatment ANB angle was achieved in 42% of patients and was more likely in females and those with larger pretreatment ANB angles. Ideal soft-tissue Holdaway angles (7 degrees to 14 degrees ) were achieved in 49% of patients and were more likely in females and those with smaller initial SNA angles. Mandibular incisor decompensation was incomplete in 28% of patients and was more likely in females and patients with greater pretreatment mandibular incisor proclination. Correction of increased overbite was generally successful, although anterior open bites were found in 16% of patients at the end of treatment. These patients were more likely to have had initial open bites.
CONCLUSIONS:

Mandibular surgery had a good success rate in normalizing the main dental and skeletal relationships. Less ideal soft-tissue profile outcomes were associated with larger pretreatment SNA-angle values, larger final mandibular incisor inclinations, and smaller final maxillary incisor inclinations. The use of mandibular surgery to correct anterior open bite was associated with poor outcomes.