Effect of Temperature of Sodium Hypochlorite on Cyclic Fatigue Resistance of Heat-treated Reciprocating Files.

INTRODUCTION: The aim of this study was to evaluate the effect of different temperatures of sodium hypochlorite (NaOCl) on the cyclic fatigue resistance of the heat-treated file systems. METHODS: The cyclic fatigue resistance of Reciproc 25 (VDW Dental, Munich, Germany), Reciproc Blue R25 (VDW), WaveOne Primary (Dentsply Maillefer, Ballaigues, Switzerland), WaveOne Gold Primary (Dentsply Maillefer), and One Shape (25.06; Micro Mega, Besançon, France) was tested in the following conditions: control (no immersion), immersion in distilled water (DW) at 37°C ± 1°C, immersion in DW at 60°C ± 1°C, immersion in NaOCl at 37°C ± 1°C, and immersion in NaOCl at 60°C ± 1°C. The immersion period was 5 minutes for all conditions. A stainless steel artificial canal with a curvature of 60° and a 5-mm radius was used. The time to failure and fragment lengths were recorded for each instrument, and data were subjected to statistical analysis. RESULTS: Reciproc Blue showed greater cyclic fatigue resistance in all conditions compared with the other systems (P < .05). Immersion in NaOCl at 60 °C negatively affected all instruments' cyclic fatigue resistance except Reciproc Blue. Immersion in DW at 60 °C increased the cyclic fatigue resistance of Reciproc Blue. Heat-treated files presented higher fatigue resistance than traditional files. CONCLUSIONS: A high temperature of NaOCl affected the cyclic fatigue life of the file systems. Instruments produced with heat treatment presented a longer fatigue life.

Fracture resistance of simulated immature teeth after internal bleaching procedures.

The aim of this study was to evaluate the fracture resistance of simulated immature teeth after internal bleaching. The teeth were assigned as follows (n = 12/group); Group-1: The pulp chamber was filled with ProRootMTA and bleached intracoronally with sodium perborate mixed with 37% carbamide peroxide gel; Group-2: The pulp chamber was filled with ProRootMTA without bleaching; Group-3: The pulp chamber was filled with Biodentine and bleached intracoronally as Group-1; Group-4: The pulp chamber was filled with Biodentine without bleaching; and Group-5: Teeth received no intervention (control). The specimens were loaded vertically until root fracture occurred. The data were analysed with Kruskal-Wallis and Dunn tests. There was no significant difference between the fracture resistances of the experimental groups (P > 0.05). However, all experimental groups had significantly lower fracture resistance than the control group (P < 0.05). Neither the tested calcium silicate cements nor the bleaching procedures had a significant impact on fracture resistance values.

Effect of Laser-Activated Irrigation on the Push-Out Bond Strength of ProRoot Mineral Trioxide Aggregate and Biodentine in Furcal Perforations.

OBJECTIVE: The objective of the present study was to assess the effect of erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser-activated irrigation (LAI) of NaOCl on the push-out bond strength of furcal perforations repaired with ProRoot mineral trioxide aggregate (MTA) and Biodentine. BACKGROUND DATA: Several studies investigated the adhesion of calcium silicate-based cements after exposure to endodontic irrigants, while effect of LAI on bond strength remains to be elucidated. MATERIALS AND METHODS: Bur-cut furcal perforations with standard dimensions were created in 100 extracted human mandibular molars. Teeth were randomly distributed into two groups (n = 50/group) according to the repair material applied: (1) ProRoot MTA or (2) Biodentine. The specimens were further assigned into five subgroups according to the irrigation regimens used over the set materials: (a) distilled water with needle irrigation; (b) 5.25% NaOCl with needle irrigation; (c) distilled water with LAI; (d) 5.25% NaOCl with LAI; and (e) no irrigation (control). Bond strengths of the test materials were assessed by using push-out bond strength test. RESULTS: Biodentine showed significantly higher dislocation resistance than ProRoot MTA (p < 0.05). Laser activation of 5.25% NaOCl and distilled water did not significantly affect the push-out bond strength results (p > 0.05). CONCLUSIONS: Biodentine showed higher dislocation resistance than ProRoot MTA as a perforation repair material. Er,Cr:YSGG laser activation of irrigation aqueous solutions had no adverse effect on push-out bond strength of Biodentine and ProRoot MTA.

Effect of Laser-Activated Irrigation with Ethylene Diaminetetraacetic Acid and Phytic Acid on the Removal of Calcium Hydroxide and Triple Antibiotic Paste from Root Dentin.

OBJECTIVE: This study assessed the efficacy of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser-activated irrigation (LAI) of ethylene diaminetetraacetic acid (EDTA) and phytic acid on the removal of calcium hydroxide (CH) and triple antibiotic paste (TAP) from root canals. BACKGROUND DATA: Although some studies investigated the efficacy of LAI of EDTA irrigation, no study has been conducted to investigate the efficacy of LAI of phytic acid in the removal of CH and TAP from root dentin. MATERIALS AND METHODS: Root canals of extracted maxillary incisors (n = 80) were instrumented using rotary files and thereafter were split longitudinally. Following preparation of a standardized groove in the apical region of one root half, the roots were randomly divided into two groups according to the intracanal medicaments placed into the grooves: (1) CH and (2) TAP. The roots were reassembled, and the specimens were further assigned into four groups (n = 10/group) defined by the final irrigation solution (EDTA and phytic acid) and irrigation technique (needle irrigation and LAI) used for removal of the medicaments. The data were analyzed statistically using Kruskal-Wallis and Mann-Whitney U tests. RESULTS: For both EDTA and phytic acid, LAI was more efficient than needle irrigation in removing both CH and TAP (p < 0.05), but none of the tested techniques completely removed CH. Irrespective of the tested irrigation solutions and techniques, significantly less TAP remained in canals (p = 0.0001), with TAP being completely removed by LAI. Irrigation with phytic acid showed better removal efficacy than EDTA in the absence of statistical significance. CONCLUSIONS: Er,Cr:YSGG LAI of EDTA and phytic acid completely removed TAP and effectively reduced CH on root dentin.

Calcium hydroxide dressing residues after different removal techniques affect the accuracy of Root-ZX apex locator.

OBJECTIVES: This study compared the ability of several techniques to remove calcium hydroxide (CH) from the root canal and determined the influence of CH residues on the accuracy of the electronic apex locator. MATERIALS AND METHODS: Root canals of 90 human maxillary lateral incisors with confirmed true working length (TWL) were prepared and filled with CH. The teeth were randomly assigned to one of the experimental groups according to the CH removal technique (n = 14): 0.9% saline; 0.9% saline + master apical file (MAF); 17% ethylenediamine tetraacetic acid (EDTA); 17% EDTA + MAF; 5.25% sodium hypochlorite (NaOCl); 5.25% NaOCl + MAF. Six teeth were used as negative control. After CH removal, the electronic working length was measured using Root-ZX (Morita Corp.) and compared with TWL to evaluate Root-ZX accuracy. All specimens were sectioned longitudinally, and the area of remaining CH (CH) and total canal area were measured using imaging software. RESULTS: The EDTA + MAF and NaOCl + MAF groups showed better CH removal than other groups (p < 0.05). Root-ZX reliability to prevent overestimated working length to be > 85% within a tolerance of ± 1.0 mm (p < 0.05). There was strong negative correlation between amount of CH residues and EAL accuracy (r = -0.800 for ± 0.5 mm; r = -0.940 for ± 1.0 mm). CONCLUSIONS: The mechanical instrumentation improves the CH removal of irrigation solutions although none of the techniques removed the dressing completely. Residues of CH medication in root canals affected the accuracy of Root-ZX adversely.

Bond strength of a calcium silicate-based sealer tested in bulk or with different main core materials.

The aim of this study was to evaluate the influence of a calcium silicate-based sealer (iRoot SP), with or without a core material, on bond strength to radicular dentin, in comparison with various contemporary root filling systems. Root canals of freshly extracted single-rooted teeth (n = 60) were instrumented using rotary instruments. The roots were randomly assigned to one of the following experimental groups: (1) a calcium silicate-based sealer without a core material (bulk-fill); (2) a calcium silicate-based sealer + gutta-percha; (3) a calcium silicate-based sealer + Resilon; (4) a methacrylate resin-based sealer (RealSeal SE) + Resilon; (5) an epoxy resin-based sealer (AH Plus) + gutta-percha, and (6) a mineral trioxide aggregate-based endodontic sealer (MTA Fillapex) + gutta-percha. Four 1-mm-thick sections were obtained from the coronal aspect of each root (n = 40 slices/group). Push-out bond strength testing was performed at a cross-head speed of 1 mm/min, and the bond strength data were analyzed statistically by one-way analysis of variance and Tukey tests (p < 0.05). The highest and lowest debonding values were obtained for the calcium silicate-based sealer bulk-fill and mineral trioxide aggregate-based endodontic sealer + gutta-percha groups, respectively (p < 0.05). It was concluded that the calcium silicate-based sealer showed higher resistance to dislocation in the bulk-filled form than in conjunction with the tested core filling materials. When the calcium silicate-based sealer was placed in bulk, its dislocation resistance was similar to that of commonly used sealer + core root filling systems. Thus, the concept of using a calcium silicate-based sealer in bulk can be more easily advocated in clinical practice.

Bond strength of mineral trioxide aggregate to root dentin after exposure to different irrigation solutions.

AIM: The aim of the study was to evaluate the regional push-out bond strength of mineral trioxide aggregate (MTA) after exposure to sodium hypochlorite (NaOCl), ethylenediaminetetraacetic (EDTA), and peracetic acid (PAA) irrigation solutions. MATERIALS AND METHODS: 1-mm-thick longitudinal slabs of root dentin were obtained from freshly extracted human canine teeth (n = 80). Simulated root perforation defects, 1 mm in diameter, were prepared in the coronal, middle, and apical thirds of radicular dentin. Mineral trioxide aggregate was placed into the cavities, and the specimens were stored for 1 week at 37°C. Thereafter, the specimens were randomly divided into four groups (n = 20) according to the irrigation solution applied over the repair sites: Group 1-10 ml of 5.25% NaOCl for 10 min; Group 2-10 ml of 5.25% NaOCl for 10 min, followed by 5 ml 17% EDTA for 5 min; Group 3-10 ml of 5.25% NaOCl for 10 min, followed by application of 5 ml 1% PAA for 5 min; and Group 4-no irrigation. Push-out test was performed at a crosshead speed of 1 mm/min. Debonding values were compared statistically using two-way analysis of variance and Tukey tests (P < 0.05). RESULTS: The push-out bond strength of MTA was not affected by the type of irrigation solution or location of the perforation defects (both P < 0.05). Stereomicroscopic inspection of the samples showed that the bond failure was predominantly adhesive. CONCLUSION: Exposure of repaired root perforations to 5.25% NaOCl, 17% EDTA, or 1% PAA does not alter the dislocation resistance of MTA at different locations of root dentin.

Intentional replantation of a hopeless tooth with the combination of platelet rich plasma, bioactive glass graft material and non-resorbable membrane: a case report.

Intentional replantation can be an alternative choice for periodontally involved hopeless tooth at least for a period of time. This technique may help to restore an original tooth to function in the mouth instead of replacing it with prosthesis. The combination of one or more techniques currently available for periodontal therapy may have the potential to enhance clinical results as compared to any of the techniques used alone. In this case report, intentional replantation was combined with regenerative techniques. A very popular agent, platelet rich plasma was used in combination with bioactive glass graft material and non-resorbable PTFE membrane. The technique and one year results of treatment were discussed radiographically and clinically.