Comparison of different methods involved in the planning of clinical crown lengthening surgery

There is little material in the literature that compares biological width measurements in periapical and bite-wings radiographs with clinical measurements. The purpose of this study was to compare measurements of biological width taken by three different methods which are frequently used for planning periodontal surgery - periapical radiograph, bite-wing radiograph and transperiodontal probing - with the trans-surgical measurements. Thirty-four sites from twenty-one subjects were analyzed. The intra-class correlation coefficients between measurements obtained trans-surgically (gold standard) and those obtained by transperiodontal probing, periapical radiography and bite-wing radiography were determined. Average measurements were compared using the Wilcoxon test at a significance level of 0.05. Also, the frequency distribution of differences between test measurements and the gold standard was calculated. The results showed that transperiodontal probing (mean 2.05 mm) was the most accurate measurement, as compared to the gold standard (mean 1.97 mm), with no statistically significant difference observed. On the other hand, periapical and bite-wing radiographic mean values (1.56 mm and 1.72 mm, respectively) were smaller than the gold standard, with statistically significant differences (p < 0.05). It was concluded that transperiodontal probing was the most accurate measurement, as compared to the gold standard, followed by that obtained with the bite-wing radiograph. The clinical relevance of these results could be that planning for crown lengthening surgery should, preferably, include transperiodontal probing.

Relationship between dental size and normal occlusion in Brazilian patients

The present study was performed on dental casts and lateral cephalometric films of 30 Caucasian Brazilian individuals (15 males and 15 females) aged 18 to 27 years and 4 months, all presenting normal occlusion and satisfactory facial profile. The aims were to investigate the existence of dental discrepancies according to Bolton's criteria, to obtain mean values for overbite, overjet, curve of Spee and interincisal angle, and to demonstrate any correlation among these parameters. A single calibrated operator measured each variable characteristics and the process was recorded twice with an accurate modified digital caliper. It was observed that the sample of normal occlusion did not present any dental discrepancy among the 12 teeth of opposite arches. The overall ratio (91.46) and anterior ratio (77.83) were in accordance with those proposed by Bolton. The mean values for normal occlusion in this Brazilian sample were defined as: 2.45 mm for overbite; 1.92 mm for overjet; 1.01 mm for curve of Spee and 129.57° for interincisal angle. A statistically significant correlation was found between overjet and overbite.

O presente estudo foi realizado em modelos de gesso e radiografias cefalométricas laterais de 30 indivíduos brasileiros, leucodermas, sendo 15 do sexo feminino e 15 do sexo masculino, com idades variando de 18 anos a 27 anos e 4 meses, todos portadores de oclusão excelente e bom perfil facial. Os objetivos foram verificar a existência de discrepância dentária de Bolton, obter valores médios para a sobremordida (overbite), sobressaliência (overjet), curva de Spee e ângulo interincisivo e verificar a existência de correlação entre essas variáveis. As medições foram realizadas por um único avaliador e o procedimento realizado duas vezes com auxílio de um paquímetro digital modificado de alta precisão. Observou-se que a amostra de oclusão normal não apresentou discrepância dentária entre os doze dentes dos arcos opostos e as razões total (91,46) e anterior (77,83) foram próximos aos dos propostos por Bolton. Os valores médios encontrados como padrão para a amostra de oclusão normal de indivíduos brasileiros foram determinados em: 2,45 mm para a sobremordida; 1,92 mm para a sobressaliência; 1,01 mm para a curva de Spee e 129,57(0) para o ângulo interincisivo, havendo apenas correlação significativa entre sobressaliência e as classes de sobremordida.