Comparative Evaluation of Efficacy of Three Single File Retreatment Systems for Removal of Gutta Percha and Assessment of Root Canal Transportation - An In Vitro Study

Background: In comparison to multiple file systems, recent advancements in single file retreatment systems had reduced the working time and ease of operation for clinicians. Aim: To compare the efficacy of retreatment systems compared with hand instrumentation, by evaluating their removal efficacy, time required for retreatment and assessment of canal transportation. Methods and Material: Forty premolars were instrumented using ProTaper Gold gold files. Post instrumentation, scan was taken, obturated using warm vertical compaction technique, and stored in artificial saliva for three months and randomly divided into four groups for retreatment. Hand instrumentation (Hi), Neoniti (Nn), Mtwo R (Mt), WaveOne Gold (Wg). Post retreatment, scan was taken. Teeth were sectioned longitudinally and photographed under the stereomicroscope. Retreatment time was recorded, and canal transportation was calculated. Statistical Analysis: The results were analyzed using one?way analysis of variance (ANOVA) followed by Tukey’s post hoc test at 95% confidence level. Results: The retreatment time was significantly longer in the Hi group. Within the test groups, a significantly longer time has been taken by Wg (p < 0.05) compared to Mt and Nn. There was no difference in the canal transportation between the single file systems at 3 mm, 6 mm and 9 mm from the apex, there was statistically significant higher transportation for the Hi group at 9 mm from the apex (p < 0.05). Conclusions: All techniques were effective in removal of filling material with minimal canal transportation. Wg system was shown to increased time compared to Nn and Mt systems. Hi group was slowest with maximum canal transportation at 9 mm from the apex.

Apically extruded debris in filling removal of curved canals using 3 NiTi systems and hand files

Abstract The aim of this study was to assess the amount of apically extruded debris during filling removal with WaveOne Gold (WOG), ProTaper Universal Retreatment (PTR), D-RaCe Retreatment (DRR) or hand files (HF), to compare the working time during filling removal, and to describe failures of NiTi instruments. Forty mesiobuccal roots of maxillary first molars were prepared with WOG Primary, obturated and divided into 4 groups (n=10), according to the instruments used: WOG, PTR, DRR or HF. Distilled water was used as irrigant and the extruded debris were collected in Eppendorf tubes and dried. The amount of extruded debris was determined by subtracting the final from the initial weight. The time of filling removal for each canal was recorded and the instruments used were analyzed pre and post-operatively by SEM. Kruskal-Wallis and Dunn's test analyzed extruded debris data and ANOVA, followed by Tukey's test, compared the working time data (a=0.05). Instrument deformation and fracture were described. WOG produced significantly less debris compared with HF and DRR (p<0.05), and similar to PTR (p>0.05). HF, PTR and DRR showed no significant difference (p>0.05). Working time in HF group was significantly higher than others (p<0.05). SEM analyses showed, from the 18 instruments evaluated, 3 fractures and 10 deformations. All instruments tested caused debris extrusion. WOG was associated with less extrusion than DRR and HF. Filling removal with HF was slower than with the other instruments. All NiTi systems presented fracture and deformation.

Resumo O objetivo deste estudo foi avaliar a extrusão apical de debris durante a desobturação com WaveOne Gold (WOG), ProTaper Universal Retratamento (PTR), D-RaCe (DRR) ou limas manuais (HF), comparar o tempo de trabalho durante a desobturação, e descrever as falhas dos instrumentos de NiTi. Quarenta canais de raízes mésio-vestibulares de primeiros molars superiores foram preparados com WOG Primary, obturados e divididos em 4 grupos (n = 10), de acordo com os instrumentos a serem utilizados: WOG, PTR, DRR ou HF. Água destilada foi utilizada como irrigante, e os debris extruídos foram coletados em tubos Eppendorf e secos. A quantidade de debris extruídos foi determinada subtraindo-se o peso inicial do peso final. O tempo de cada desobturação foi anotado e os instrumentos utilizados foram analisados no pré e pós-operatório em MEV. Os testes Kruskal-Wallis e Dunn foram utilizados para analisar os dados da extrusão de debris, e os testes ANOVA e Tukey para comparar os dados do tempo de trabalho (a=0.05). As deformações e fraturas dos instrumentos foram descritas. O grupo WOG produziu significativamente menos debris quando comparado aos grupos HF e DRR (p<0.05), e foi similar ao grupo PTR (p>0.05). Os grupos HF, PTR e DRR não apresentaram diferença estatisticamente significante (p>0.05). O tempo de trabalho no grupo HF foi significativamente maior do que nos outros grupos (p<0.05). A análise em MEV mostrou que, dos 18 instrumentos avaliados, 3 fraturaram e em 10 foi observado deformação. Todos os sistemas testados causaram extrusão apical de debris. WOG foi associado com menor extrusão do que DRR e HF. A desobturação com HF foi mais lenta do que com os demais instrumentos. Todos os sistemas de NITI apresentaram fratura e deformação.