Endodontic Retreatment Using a Single Instrument from four Nickel-Titanium Systems - A Micro-CT Study.

This study evaluated the efficiency of using a single instrument from three different rotary multi-file systems and compared them with that of a reciprocating single-file for endodontic retreatment by means of micro-CT. Sixty extracted canines were prepared using a size F2 ProTaper Universal file and obturated. After 30 days of storage at 37ºC and 100% humidity, the teeth were randomly divided into four groups (n=15) based on the type of instrument used to retreatment: ProTaper Next (PTN), ProTaper Gold (PTG), TRUShape 3D (TS), and WaveOne (WO). The canals were retreated using only the size 40 instrument from each system according to the manufacturer's recommendations for torque and speed. The time required to remove the filling material was recorded in seconds. The amount of initial and residual filling material and the quantity of dentin removed were assessed by means of micro-CT. Data were statistically analyzed (ANOVA and Kruskal-Wallis) at a 5% significance level. TS instruments required the highest (p<0.05) amount of time (mean, 384.80 ±144.92) compared with the WO (229.67±68.16) and PTG (248.67±64.22) and not so different from PTN instruments (327.67±133.3). No differences in the amount of dentin removed, initial and residual filling volume, and percentages of filling material were observed among the groups. The use of a single rotary instrument from the PTG, TS, and PTN systems was as effective as that of the single-file reciprocating WO system. However, none of the instruments was able to remove the filling materials completely.

Endodontic retreatment using a single instrument from four nickel-titanium systems - a micro-ct study

Abstract This study evaluated the efficiency of using a single instrument from three different rotary multi-file systems and compared them with that of a reciprocating single-file for endodontic retreatment by means of micro-CT. Sixty extracted canines were prepared using a size F2 ProTaper Universal file and obturated. After 30 days of storage at 37ºC and 100% humidity, the teeth were randomly divided into four groups (n=15) based on the type of instrument used to retreatment: ProTaper Next (PTN), ProTaper Gold (PTG), TRUShape 3D (TS), and WaveOne (WO). The canals were retreated using only the size 40 instrument from each system according to the manufacturer's recommendations for torque and speed. The time required to remove the filling material was recorded in seconds. The amount of initial and residual filling material and the quantity of dentin removed were assessed by means of micro-CT. Data were statistically analyzed (ANOVA and Kruskal-Wallis) at a 5% significance level. TS instruments required the highest (p<0.05) amount of time (mean, 384.80 ±144.92) compared with the WO (229.67±68.16) and PTG (248.67±64.22) and not so different from PTN instruments (327.67±133.3). No differences in the amount of dentin removed, initial and residual filling volume, and percentages of filling material were observed among the groups. The use of a single rotary instrument from the PTG, TS, and PTN systems was as effective as that of the single-file reciprocating WO system. However, none of the instruments was able to remove the filling materials completely.

Resumo Este estudo laboratorial avaliou por meio de micro-CT a eficiência do uso de um único instrumento de três sistemas rotatórios em retratamentos endodônticos, comparados a um instrumento único reciprocante. Sessenta caninos extraídos foram preparados usando o sistema ProTaper Universal (F2) e obturados. Após 30 dias de armazenamento a 37 ºC e 100% de umidade, os dentes foram divididos aleatoriamente em quatro grupos (n = 15), de acordo com o instrumento utilizado para remover as obturações endodônticas: ProTaper NEXT (PTN), ProTaper Gold (PTG), TRUShape 3D (TS) e WaveOne (WO). Os canais foram retratados usando apenas o instrumento tamanho 40 de cada sistema, seguindo as recomendações do fabricante para torque e velocidade. O tempo necessário para remover a obturação foi registrado em segundos. A quantidade de material remanescente e o volume de dentina removida foram avaliadas por meio de micro-CT. Análise estatística foi realizada (ANOVA e Kruskal-Wallis), com nível de significância de 5%. O tempo de trabalho no grupo TS foi significativamente maior (p<0.05) (média, 384,80 ± 144,92) comparado a WO (229,67 ± 68,16) e PTG (248,67 ± 64,22), e similar a PTN (327,67 ± 133,3). Não houve diferenças entre os grupos na quantidade de dentina removida e nas porcentagens de material obturador residual. O uso de apenas um instrumento rotatório dos sistemas PTG, TS e PTN foi tão eficaz quanto o do sistema WO reciprocante na remoção do material obturador. No entanto, nenhum dos instrumentos conseguiu remover completamente os materiais obturadores.

Efficacy of protaper instruments during endodontic retreatment.

INTRODUCTION: The effectiveness of ProTaper Universal and ProTaper Retreatment rotary instruments was compared to the Hedström files in the removal of filling material from root canals. MATERIALS AND METHODS: Thirty-six extracted human mandibular premolars with a single straight root canal were shaped and filled with gutta-percha and AH Plus. The specimens were stored for 6 months at 37°C and at 100% relative humidity, and then randomly divided into three groups: PTU - removal of filling material performed with ProTaper Universal instruments; PTR - removal of filling material performed with ProTaper Retreatment instruments; HF - removal of filling material performed with Gates-Glidden burs, Hedström files and solvent. After the filling material removal and diaphanization, the specimens were longitudinally sectioned and images of the canal surfaces were scanned. The remaining areas of filling material were measured (Image Tool 3.0), and data was analyzed statistically (Kruskal-Wallis and Dunn tests). The time required for filling removal in each group was also recorded (one-way ANOVA and Tukey's HSD test). RESULTS: All groups presented remnants of filling material; PTU had the smallest amount and HF group presented the highest mean value (P< 0.05) in all the thirds. The cervical third had the smallest amount of material when compared with the other thirds (P< 0.05). HF group required a longer mean time, presenting significant difference (P< 0.05). CONCLUSION: Considering the time required and the amount of the filling removal, ProTaper Retreatment were not superior to ProTaper Universal, but both rotary instruments were more effective and less time-consuming than Hedström manual files.