Mateus Silveira Martins Hartmann

Computed tomography assessment of the efficiency of different techniques for removal of root canal filling material

This study evaluated the efficiency of different techniques for removal of filling material from root canals, using computed tomography (CT). Sixty mesial roots from extracted human mandibular molars were used. Root canals were filled and, after 6 months, the teeth were randomly assigned to 3 groups, according to the root-filling removal technique: Group A - hand instrumentation with K-type files; Group B - reciprocating instrumentation with engine-driven K-type files; and Group C rotary instrumentation with engine-driven ProTaper system. CT scans were used to assess the volume of filling material inside the root canals before and after the removal procedure. In both moments, the area of filling material was outlined by an experienced radiologist and the volume of filling material was automatically calculated by the CT software program. Based on the volume of initial and residual filling material of each specimen, the percentage of filling material removed from the root canals by the different techniques was calculated. Data were analyzed statistically by ANOVA and chi-square test for linear trend (?=0.05). No statistically significant difference (p=0.36) was found among the groups regarding the percent means of removed filling material. The analysis of the association between the percentage of filling material removal (high or low) and the proposed techniques by chi-square test showed statistically significant difference (p=0.015), as most cases in group B (reciprocating technique) presented less than 50% of filling material removed (low percent removal). In conclusion, none of the techniques evaluated in this study was effective in providing complete removal of filling material from the root canals.

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 post-instrumentation 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 Tukeys 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.

Histologic evaluation of human pulp tissue after orthodontic intrusion.

INTRODUCTION The forces applied during orthodontic treatment bring about effects on the teeth and surrounding tissues. The aim of this study was to evaluate the possible changes in the human pulpal tissue resulting from orthodontic intrusion in a 21-day period using histologic examination. METHODS The sample consisted of 17 young individuals of both sexes between the ages of 12 and 19 years. A total of 34 premolars were evaluated with orthodontic indication of extraction. Because it is a split-mouth study, in each patient, intrusion force of 60 g was applied randomly on 1 of the dental elements experimental group for 21 days. The counterpart control group received no force. After extractions, these dental elements were fixed in 10% formaldehyde, processed automatically, submitted to histotechnical preparation, and stained with hematoxylin-eosin for analysis under optical microscope. RESULTS The paired Fisher exact test (P ≤ .05) showed a significant increase of fibrous tissue in the experimental group. The nonparametric paired Wilcoxon test (P ≤ .05) showed a significant increase in the number of pulpal nodules in the elements of the experimental group and showed no difference in the number of blood vessels between the groups. Large-caliber vessels and congested elements were observed in 8 of the experimental group elements. CONCLUSIONS The orthodontic intrusion force, in these conditions, caused vascular changes in the pulpal tissue and also increased the presence of fibrosis and the number of pulp calcifications in the experimental elements.

Prevalência de Lesões Periapicais Observadas em Radiografias Panorâmicas

The present study had as objective to perform an epidemiological survey on radiolucent periapical lesions prevalence in a sample of 107 panoramic radiographs of patients in the graduation course in Dentistry school IMED. Patients included have panoramic radiographs performed in the year 2015 and with the term of Free and Informed Consent signed. The data collection regarded panoramic reports exams and radiographs. The criteria was: periapical lesion presence visible in radiographic, patient’s gender, age, total number of teeth, dental element, arch and number of endodontic treatments. The data were organized and compared. The results showed that 53.3% of the radiographic reports had a periapical lesion. Most of the lesions were in the maxilla, with 58.5% of the occurrences and the most affected dental elements were 22 and 26. In conclusion, periapical lesions were more frequent in women in the upper arch on lateral incisors and upper first molars.

Patência apical nos canais radiculares dos primeiros molares superiores

Objetivos: O objetivo deste estudo foi avaliar, ex vivo, a porcentagem da obtencaode patencia apical nos canais radiculares dos primeiros molares superiores permanentese a influencia da ampliacao cervical nesta verificacao.Metodo: Foram analisados 73 primeiros molares superiores permanentes, selecionadosatraves de exame visual e radiografico. Para a execucao do estudo, os dentesforam previamente abordados e os canais radiculares localizados. A patenciaapical foi verificada utilizando-se instrumentos de aco inoxidavel #08 ou #10, deacordo com o diâmetro de cada canal radicular. Quando nao se conseguia a patenciaapical, o terco cervical foi ampliado, com brocas de Gates-Glidden #1 e #2,seguidas de brocas LA Axxess #20 e a tentativa de obtencao de patencia, executadanovamente.Resultados: Os resultados obtidos, com relacao a presenca de patencia apical, foramde 79,45% para os canais radiculares mesiovestibulares, 29,62% para os canaisradiculares mesiopalatinos, 72,60% para os canais radiculares distovestibulares e84,93% para os canais radiculares palatinos.Conclusao: Pode-se concluir que a ampliacao do terco cervical aumentou em 8,42%a obtencao de patencia apical em todos os canais radiculares.

Avaliação da infiltração marginal dos materiais MTA, Cimento de Portland e Ionômero de Vidro empregados em obturações retrógadas

Objetivos. Avaliar o selamento apical promovido pelo MTA, cimento de Portland e ionomero de vidro em retrocavidades de dentes incisivos centrais superiores humanos. Metodo. Trinta incisivos centrais superiores foram tratados endodonticamente e tiveram sua porcao apical seccionada, cavidades retrogadas foram preparadas e em seguida divididas em tres grupos de dez dentes cada, da seguinte forma: Grupo1 – MTA; Grupo 2 – cimento de Portland; e Grupo 3 – ionomero de vidro. Dois dentes ainda foram utilizados, um como controle positivo e outro como controle negativo. Apos a imersao no corante rodamina B a 0,2% por 48h a 37oC as raizes foram clivadas e o padrao de infiltracao foi mensurado. Os dados foram analisados utilizando-se ANOVA seguido pelo Teste Post Hoc de Bonferroni (p 0,05). Conclusao. Segundo a metodologia empregada, concluiu-se que o material que proporcionou o melhor selamento apical em retrobturacoes endodonticas foi o ionomero de vidro.