Influence of Apical Preparation Size and Working Length on Debris Extrusion

Abstract The aim of this study was to quantitatively evaluate the amount of apically extruded debris by single-file reciprocating instruments with different working lengths and apical preparation sizes. Eighty human single-rooted mandibular incisors were used and conventional access cavities were prepared. Then, the specimens were divided into four groups (n=20), according to root canal instrumentation: Reciproc size 25, .08 taper and Reciproc size 40, .06 taper instruments were used at the foramen; Reciproc size 25, .08 taper and Reciproc size 40, .06 taper instruments were used 1 mm short of the foramen. Distilled water was used as an irrigant and the apically extruded debris were collected in pre-weighted glass vials and dried afterwards. The mean weight of debris was weighed with a microbalance and statistically analyzed using one-way analysis of variance and the post hoc Tukey multiple comparison test (p<0.05). The results showed that all experimental groups were associated with debris extrusion. No significant difference was found in the amount of apically extruded debris among all experimental groups (p>0.05). The present study demonstrated that the working length and the apical preparation size did not have a significant effect on debris extrusion when performing single-file reciprocating instrumentation.

Resumo Este estudo avaliou quantitativamente a quantidade de material extruído apicalmente pela instrumentação com lima única reciprocante, aplicando diferentes comprimentos de trabalho e tamanhos de preparo apical. Para a análise de extrusão foram utilizados oitenta incisivos inferiores unirradiculares humanos. Cavidades de acesso convencionais foram preparadas e os espécimes foram divididos em quatro grupos (n=20), de acordo com o tipo de instrumentação do canal: Reciproc 25, 0.08 e Reciproc 40, 0.06 foram utilizadas na instrumentação até o forame; Reciproc tamanho 25, 0.08 e Reciproc 40, 0,06 foram utilizadas na instrumentação até 1 mm aquém do forame. Água destilada foi empregada como irrigante e o material extruído apicalmente foi coletado em frascos de vidro já pesados e posteriormente submetidos a secagem. O peso médio de detritos foi avaliado com uma microbalança de precisão e os dados submetidos a ANOVA e teste Tukey (p<0,05). Todos os grupos experimentais foram associados à extrusão de debris. Nenhuma diferença significativa foi encontrada na quantidade de material extruído apicalmente entre os grupos (p>0,05). Este estudo demonstrou que o comprimento de trabalho e o tamanho do preparo apical não geraram efeito significativo sobre a extrusão de debris durante a instrumentação reciprocante.

Evaluation of photodynamic therapy using a diode laser and different photosensitizers against Enterococcus faecalis

Photodynamic therapy (PDT) has been proven to be effectivein disinfecting root canals. The aim of this present study wasto evaluate the effects of PDT on the viability of Enterococcusfaecalis using methylene blue (MB) and malachite green(MG) as photosensitizers. Solutions containing E. faecalis(ATCC 29212) were prepared and harvested by centrifugationto obtain cell suspensions, which were mixed with MBand MG. Samples were individually irradiated by the diodelaser at a distance of 1mm for 30, 60, or 120 seconds. Colonyformingunits (CFU) were determined for each treatment.PDT for 60 and 120 seconds with MG reduced E. faecalis viabilitysignificantly. Similar results were obtained when MBwas used as photosensitizer. PDT using MB and MG haveantibacterial effect against E. faecalis, showing potential tobe used as an adjunctive antimicrobial procedure in endodontictherapy...