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

Evaluation of optical density of bone defects filled with calcium phosphate cement and bioactive glass in rats Avaliação da densidade óptica de cavidades ósseas preenchidas com cimento de fosfato de cálcio e vidro bioativo em ratos

Purpose: To evaluate new bone formation, by the analysis of optical density, in rat femoral defects filled with calcium phosphate cement (CPC) and bioactive glass (BG). Methods: Twenty-one rats were divided into three groups, Group I (CPC), Group II (BG), and Group III (control), and assessed after 7, 15, and 30 days. Three bone cavities were made in the left femur and filled with CPC, BG, and no material (control). Digital images were obtained and the results were subjected to statistical analysis of variance (ANOVA), complemented by the Friedman and Kruskal-Wallis nonparametric tests, with a significance level of 5%. Results: Regarding optical density, Group I showed statistical values significantly higher than Group III and also higher, although not statistically significant, than Group II, in all observation periods. When Groups II and III were compared, Group II showed higher optical density values, without statistically significant differences, in all periods. Conclusion: The biomaterials analyzed showed higher optical density in relation to the control group in all observation periods, calcium phosphate cement being the best option in the repair of bone defects, but without statistically significant differences in relation to bioactive glass.<br>Objetivo: Avaliar a neoformação óssea, por meio da análise de densidade óptica, em cavidades em ratos preenchidas com cimento de fosfato de cálcio (CFC) e vidro bioativo (VB). Métodos: Utilizou-se 21 ratos distribuídos em três grupos, sendo Grupo I (CFC), Grupo II (VB) e Grupo III (controle) avaliados em 07, 15 e 30 dias. Foram realizadas três cavidades, junto ao fêmur esquerdo e preenchidas com CFC, VB e sem material (controle). Realizaram-se radiografias digitais e os resultados foram submetidos à análise estatística de variância (ANOVA), complementada através dos testes não-paramétricos de Friedman e Kruskal-Wallis, com níveis de significância de 5%. Resultados: Comparando a densidade óptica o Grupo I apresentou valores estatísticos significativamente maiores que o Grupo III, e também apresenta valores maiores, sem diferença estatística significativa, em todos os períodos, quando comparado ao Grupo II. Quando comparamos o Grupo II com o Grupo III, o Grupo II apresenta valores maiores de densidade óptica, sem diferença estatística significativa, em todos os períodos. Conclusão: Observou-se maior densidade óptica dos biomateriais em relação ao grupo controle em todos os períodos avaliados, sendo o cimento de fosfato de cálcio a melhor opção para restauração de cavidades ósseas, porém sem diferenças estatisticamente significantes em relação ao vidro bioativo

CT evaluation of apical canal transportation associated with stainless steel hand files, oscillatory technique and ProTaper rotary system

This study used computed tomography (CT) to compare apical canal transportation in mesiobuccal canals of maxillary molars prepared with different techniques. Sixty teeth were assigned to 3 groups (n=20), according to the technique used for root canal instrumentation: hand instrumentation with K-Flexofiles, K-Flexofiles activated by an oscillatory system and ProTaper NiTi rotary system. Pre and postinstrumentation CT images were obtained 3 mm short of the apical foramen and were superimposed to compare canal transportation. Data were analyzed statistically by ANOVA and Tukey’s test using the SPSS software (α=0.05). In the buccal direction, the manual technique produced significantly less canal transportation than the oscillatory technique (p<0.05) and both were similar to the rotary technique (p>0.05). In the distal and distopalatal directions, the oscillatory technique produced more canal transportation (p<0.05). In the mesiopalatal direction, the oscillatory technique produced more canal transportation than the manual technique (p<0.05), and both were similar to the rotary technique (p>0.05). In conclusion, all techniques produced canal transportation, and the oscillatory technique produced the greatest removal of root dentin toward the innerside of the root curvature.Este estudo utilizou a tomografia computadorizada (TC) para comparar o transporte do canal radicular nos canais mésiovestibulares de molares superiores preparados por diferentes técnicas. Sessenta molares superiores foram divididos em 3 grupos (n=20) de acordo com a técnica utilizada para o preparo do canal radicular: instrumentação manual com limas K-Flexofile, limas K-Flexofile acopladas a um sistema oscilatório e sistema rotatório ProTaper. Imagens de TC pré e pós-instrumentação foram obtidas 3 mm aquém do forame apical e superpostas para comparar o transporte do canal. Os dados foram analisados estatisticamente pela Análise de Variância (ANOVA) e Teste de Tukey utilizando o software SPSS (α=0,05). Na direção vestibular, a técnica manual produziu significantemente menos transporte do canal radicular do que a técnica oscilatória (p<0,05) e ambas foram similares a técnica rotatória (p>0,05). Nas direções distal e disto-palatina, a técnica oscilatória produziu mais transporte do canal radicular (p<0,05). Na direção mésio-palatina, a técnica oscilatória produziu mais transporte do canal radicular do que a técnica manual (p<0,05), sendo que ambas foram similares à técnica rotatória (p>0,05). Em conclusão, todas as técnicas produziram transporte do canal radicular e a técnica oscilatória produziu os maiores desgastes de dentina na direção interna da curvatura