Three-dimensional skeletal mandibular changes associated with Herbst appliance treatment.

OBJECTIVES: Three-dimensional evaluation of skeletal mandibular changes following Herbst appliance treatment. SETTING AND SAMPLE POPULATION: Retrospective case-control study, based on a sample size calculation. Twenty-five pubertal patients treated with Herbst appliance (HAG), and 25 matched Class II patients who received other non-orthopaedic dental treatments (CG). MATERIAL AND METHODS: Three-dimensional models were generated from pre-treatment (T0) and post-treatment (T1) cone beam computed tomograms. Volumetric registration on the cranial base was used to assess mandibular displacement; volumetric regional registration was performed to evaluate mandibular growth. Quantitative measurements of X, Y, Z and 3D Euclidian changes, and also qualitative visualization by colour-mapping and semi-transparent overlays were obtained. RESULTS: Downward displacement of the mandible was observed in both HAG and CG (2.4 mm and 1.5 mm, respectively). Significant forward displacement of the mandible was observed in the HAG (1.7 mm). HAG showed greater 3D superior and posterior condylar growth than the CG (3.5 mm and 2.0 mm, respectively). Greater posterior growth of the ramus was noted in the HAG than in CG. CONCLUSIONS: Immediately after Herbst therapy, a significant mandibular forward displacement was achieved, due to increased bone remodelling of the condyles and rami compared to a comparison group. Three-dimensional changes in the direction and magnitude of condylar growth were observed in Herbst patients.

First permanent molar: first indicator of dental caries activity in initial mixed dentition.

The objective of the present study was to investigate among children in the initial mixed dentition phase the presence of clinical signs that might eventually function as more sensitive indicators of the development of caries disease, denoted here as caries activity. On this basis, we investigated the relationship between salivary levels of mutans streptococci (MS) and decayed, missing and filled permanent and deciduous tooth surfaces (DMFS and dmfs) using microbiological, clinical and radiographic examinations in 81 schoolchildren aged 7-8 years. Whereas dmfs did not present a positive correlation, DMFS was significantly correlated with salivary MS levels. The first permanent molars of the schoolchildren studied comprised 87.3% of the affected surfaces recorded in the DMFS, suggesting that the development of new lesions was preferentially located on the surfaces of the first permanent molars. These results permit us to conclude that the first permanent molars function as first indicators of dental caries activity in the schoolchildren examined.

The influence of gross caries removal and temporary filling of dental caries with a zinc oxide eugenol cement on the level of mutans streptococci in saliva.

The influence of gross caries removal and temporary filling of dental caries with a zinc oxide eugenol cement on the salivary level of mutans streptococci (MS) was studied in 14 children, 6 to 8 years of age. Forty-eight hours after filling all cavities, there was a significant decrease in the level of these cariogenic microorganisms. However, after 30 days, the salivary level of mutans streptococci was similar to that detected initially.

[Infection control procedures used in dental offices in Belo Horizonte]. / Procedimentos utilizados no controle de infecção em consultórios odontológicos de Belo Horizonte.

Survey data from 300 randomly selected private dental practitioners working in Belo Horizonte, Minas Gerais, were used to evaluate the infection control procedures routinely practiced here. The function of this report might be to alert the teaching team from Dental Schools and the dentists to the problems that potentially contribute to the transmission of infectious disease as a first step for additional specific recommendations to an effective and safe infection controL program that we intend to discuss later.