The effect of two rotary and two reciprocating NiTi systems on postoperative pain after root canal retreatment on single-rooted incisor teeth: A randomized controlled trial.

AIM: This randomized clinical trial aimed to assess the effect of two rotary (ProTaper Retreatment + ProTaper Gold and Hyflex EDM) and two reciprocating (Reciproc Blue and WaveOne Gold) NiTi systems on postoperative pain after root canal retreatment on single-rooted incisor teeth. METHODOLOGY: One hundred and eighty patients scheduled for root canal retreatment were randomly assigned to one of the four groups according to the NiTi system (ProTaper Retreatment + ProTaper Gold, Hyflex EDM, Reciproc Blue or WaveOne Gold) used for the removal of root canal fillings and further canal preparation. The working length was determined to be 1 mm shorter than the '0.0' mark of the apex locator. Root canals were filled with gutta-percha and an epoxy resin-based root canal sealer using a lateral compaction technique. The teeth were restored using a resin composite material. A single operator performed the retreatments in a single visit. The incidence and intensity of postoperative pain were rated on a numeric rating scale by patients 24, 48 and 72 h after retreatment. The number of analgesic tablets (400 mg Ibuprofen) taken by patients was also recorded. Data were analysed using the Mann-Whitney U, Wilcoxon and chi-square tests. RESULTS: For the intensity of postoperative pain, the difference between the four groups was not significantly different (p > .05). No significant difference was found between the groups in terms of analgesic medication intake (p > .05). CONCLUSIONS: The rotary and reciprocating NiTi systems tested in this study were associated with similar intensity of postoperative pain and intake of analgesics following root canal retreatment on single-rooted incisor teeth completed in one visit.

Effect of solvent use on postoperative pain in root canal retreatment: a randomized, controlled clinical trial.

OBJECTIVES: The aim of this randomized clinical trial was to assess the effect of solvent use during the removal of root canal filling on postoperative pain after retreatment. MATERIALS AND METHODS: Ninety patients scheduled for root canal retreatment were randomly assigned to one of the following two groups according to the root canal filling removal procedure used: ProTaper retreatment (Dentsply Maillefer, Ballaigues, Switzerland) instruments or ProTaper retreatment instruments in combination with gutta-percha solvent. A single operator performed the retreatments in a single visit. The incidence and intensity of the postoperative pain were rated on a numeric rating scale by patients at 24, 48, and 72 h after retreatment. The analgesic tablet intake number was also recorded. Data were analyzed using Mann­Whitney U, Wilcoxon, and chi-square tests. RESULTS: For the intensity of postoperative pain, the difference between the two groups was not statistically significant. Moreover, no statistically significant difference was found between the two groups in terms of analgesic medication intake (P > 0.05). CONCLUSIONS: The processes involving the use and non-use of a solvent in the removal of root canal fillings were found to be equivalent in terms of postoperative pain intensity and analgesic intake. CLINICAL RELEVANCE: Some in vitro studies claimed that the use of a gutta-percha solvent in the removal of root canal fillings tends to reduce postoperative pain since extrusion of debris was significantly less. This randomized clinical trial indicates that the removal of root canal fillings with or without the use of a solvent was associated with equivalent postoperative pain intensity and analgesic intake. This study is registered in the www.ClinicalTrials.gov database with the identifier number NCT03756363.

Evaluation of Apically Extruded Debris from Curved Root Canal Filling Removal Using 5 Nickel-Titanium Systems.

INTRODUCTION: This study evaluated the amount of apically extruded debris in the retreatment of curved root canals using different nickel-titanium (NiTi) systems: the ProTaper Universal Retreatment (Dentsply Maillefer, Ballaigues, Switzerland), Mtwo Retreatment (VDW, Munich, Germany), D-Race Retreatment (FKG Dentaire, La Chaux-de-Fonds, Switzerland), R-Endo Retreatment (Micro-Mega, Besançon, France), and Reciproc (VDW) systems. METHODS: One hundred human mandibular premolars with curved root canals were prepared with the Reciproc #25 .08 NiTi system filled with AH Plus Jet (Dentsply DeTrey, Konstanz, Germany) sealer and gutta-percha and divided into 5 groups (n = 20). The canal filling was removed with the ProTaper, Mtwo, D-Race, and R-Endo retreatment systems and Reciproc instruments. Final preparation was done with the Reciproc #40 .06 NiTi system. Extruded debris was collected in preweighed Eppendorf tubes. The times required for retreatment were recorded. RESULTS: Reciproc produced significantly (P < .001) more debris than the other systems. ProTaper R and Mtwo R produced significantly (P < .001) more debris than D-Race and R-Endo. The Reciproc group required significantly (P < .001) less preparation time than the other groups. CONCLUSIONS: In the retreatment of curved root canals, the Reciproc system extruded significantly more debris than the rotary retreatment NiTi systems. In addition, the ProTaper and Mtwo retreatment systems extruded significantly more debris than the R-Endo and D-Race systems. The Reciproc system was significantly faster than the rotary retreatment systems.

Do the Sealer Solvents Used Affect Apically Extruded Debris in Retreatment?

INTRODUCTION: We evaluated apically extruded debris in the retreatment of root canals filled with different root canal sealers and gutta-percha using different solvents. METHODS: Ninety human mandibular central and lateral teeth were prepared using the Reciproc #25 .08 nickel-titanium system (VDW GmbH, Munich, Germany) and were divided randomly into 6 groups. In groups 1, 2, and 3, root canals were filled with epoxy resin-based sealer and gutta-percha, and in groups 4, 5, and 6, root canals were filled with zinc oxide-eugenol-based sealer and gutta-percha. Each tooth was placed in a glass vial experimental apparatus. All root canal fillings were removed with the ProTaper Retreatment nickel-titanium system (Dentsply Maillefer, Ballaigues, Switzerland). During the retreatment procedure, in group 1, Resosolv (Pierre Rolland, Merignac, France) was used; in group 4, Endosolv E (Septodont, Paris, France) was used; and in groups 2 and 5, Guttasolv (Septodont) was used as the solvent. In the control groups (groups 3 and 6), no solvent was used. Reciproc #40 .06 was used for the final preparation. The times required for retreatments were recorded. RESULTS: The weight of the extruded debris and the time required for retreatment were decreased significantly in the groups in which a solvent that was intended specifically for the root canal sealer was used (groups 1 and 4). In the Guttasolv groups (groups 2 and 5), the amount of apically extruded debris and the time required decreased for both root canal sealers. CONCLUSIONS: The amount of apically extruded debris and the duration of retreatment were reduced by the use of a solvent specific to the sealer compared with a gutta-percha solvent or no solvent.

The effect of residual calcium hydroxide on the accuracy of a contemporary electronic apex locator.

OBJECTIVE: The aim of this study was to evaluate the effect of residual calcium hydroxide [Ca(OH)2] on the accuracy of an electronic apex locator (EAL). MATERIALS AND METHODS: Working lengths (WLs) of 56 extracted maxillary incisors were determined initially by two different methods. The first method used the 'APEX' reading of the EAL as a reference point, 0.5 mm was subtracted and recorded as WL0. The second method used the '0.5' reading and the score was recorded as WL0.5 without subtraction. The roots were prepared to WL0 and divided randomly into three experimental groups (n = 16) (1 mm in group A, 2 mm in group B and 4 mm in group C) and a control (n = 8). Specimens in all experimental groups were filled with Ca(OH)2 paste. Following its removal, WLs were re-determined with the same methods. RESULTS: In group C, pre/post WLs were significantly different (p < 0.05). No significant difference was observed between the other experimental groups and the control group. CONCLUSION: Accuracy of EAL decreased proportionally with the amount of paste remaining at the ±0.5-mm tolerance level. Ca(OH)2 paste remnants may cause incorrect EAL readings.

The effect of a new-generation flowable composite resin on microleakage in Class V composite restorations as an intermediate layer.

AIM: To evaluate the effect of application a new-generation bulk-fill flowable composite resin as an intermediate material between composite resin and dental substrates on micro-leakage in Class V composite restorations. MATERIALS AND METHODS: A total of 144 Class V cavities were prepared in 72 human molars. Specimens were then randomly distributed among three groups according to adhesive system applied (Group 1: Clearfil SE Bond; Group 2: Adper Easy One; Group 3: Adhesive 200T), and each group was divided into three subgroups according to liner material used (Group A: No liner-control group; Group B: Aelite Flo LV, low viscosity microhybrid composite; Group C: Smart dentin replacement). All cavities were restored using resin composite (Aelite LS, low shrinkage posterior composite). Specimens were stained with 0.5% basic fuchsin and evaluated dye penetration. RESULTS: There was no significant difference in dye penetration was found between the control and the experimental groups. CONCLUSIONS: Micro-leakage is not affected by the application of either conventional or new-generation flowable composite resin as an intermediate material between composite resin and dental substrates.

Effects of dissolving solutions on the accuracy of an electronic apex locator-integrated endodontic handpiece.

The effects of three dissolving agents on the accuracy of an electronic apex locator- (EAL-) integrated endodontic handpiece during retreatment procedures were evaluated. The true lengths (TLs) of 56 extracted incisor teeth were determined visually. Twenty teeth were filled with gutta-percha and a resin-based sealer (group A), 20 with gutta-percha and a zinc oxide/eugenol-based sealer (group B), and 16 roots were used as the control group (group C). All roots were prepared to TL. Guttasolv, Resosolv, and Endosolv E were used as the dissolving solutions. Two evaluations of the handpiece were performed: the apical accuracy during the auto reverse function (ARL) and the apex locator function (EL) alone. The ARL function of the handpiece gave acceptable results. There were significant differences between the EL mode measurements and the TL (P < 0.05). In these comparisons, Tri Auto ZX EL mode measurements were significantly shorter than those of the TL.

The effect of peracetic acid on removing calcium hydroxide from the root canals.

INTRODUCTION: The goal of this study was to evaluate the efficiencies of different irrigation solutions in the removal of calcium hydroxide (CH). METHODS: Forty-eight maxillary central incisor teeth were used. Root canals were prepared with the ProTaper system (Dentsply Maillefer, Baillagues, Switzerland). Five milliliters 2% NaOCl, 5 mL 17% EDTA, and 10 mL saline were used for final irrigation. The canals were filled with CH paste. Specimens were randomly divided into 4 experimental groups (n = 10) according to irrigation protocols. Positive and negative control groups (n = 4) were used. Group 1 used 2.5 mL 17% EDTA, group 2 used 2.5 mL 2.5% NaOCl + 2.5 mL 17% EDTA, group 3 used 2.5 mL 1% peracetic acid (PAA), and group 4 used 2.5 mL 0.5% PAA. The specimens were evaluated with scanning electron microscope analysis and scored. Kruskal-Wallis and Student Newman-Keuls post hoc tests were used for statistical analysis. RESULTS: In the apical thirds, 1% PAA was superior to the other groups (P < .05); however, there were no significant differences among the other groups (P > .05). In the middle thirds, no significant differences were found among the groups (P > .05). In the coronal thirds, 1% PAA was superior to the other groups. There were significant differences among all the other groups (P < .05). CONCLUSIONS: According to the findings of the present study, 1% PAA could be recommended for the removal of CH from the root canals.