Evaluation of relationship between endodontic access cavity types and secondary mesiobuccal canal detection.

BACKGROUND: The aim of this study was to evaluate the relationship between Endodontic Access Cavity (EAC) types with MB2 canal detection ratio in the upper first molars. METHODS: A total of 60 roots of extracted human maxillary first molars were selected. All teeth were prepared with Point EAC (PEAC), Conservative EAC (CEAC) and Traditional EAC (TEAC) respectively. After each group were completed, extra canal was searched. Preoperative and postoperative tooth weigh was calculated using precise scale. McNemar's chi-square test and a paired test significant difference were used for statistical analyses. RESULTS: The EAC types statistically were changed of tooth tissue loss quantity (p = 0.000). MB2 detection rate of CEAC (%53,3) and TEAC (%60) are higher than statistically that of PEAC (%31.6) (p < 0.05). 8 teeth MB2 canal was detected only with the CBCT images. CONCLUSIONS: In upper molars, CEAC seems reasonable in terms of detected the MB2 canal and removed hard tissue.

In Vitro Cytotoxicity of GuttaFlow Bioseal, GuttaFlow 2, AH-Plus and MTA Fillapex.

INTRODUCTION: The aim of the present in vitro study was to evaluate the cytotoxicity of different sealers including GuttaFlow Bioseal, GuttaFlow 2, AH-Plus and MTA Fillapex on L929 murine fibroblasts. METHODS AND MATERIALS: Samples of GuttaFlow Bioseal, GuttaFlow 2, AH-Plus and MTA Fillapex were fabricated in Teflon disks of 5 mm diameter and 3 mm thickness. L929 fibroblasts were exposed to the extracts of these materials for 3, 24, 72 and 168 h at 37°C with 5% CO2. Cell viability was evaluated by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was evaluated by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. The data were analysed by ANOVA. RESULTS: GuttaFlow Bioseal was nontoxic at all experimental time points (P>0.05), whereas MTA Fillapex and AH-Plus were toxic (P<0.001). At 7 days, there were more viable cells in the GuttaFlow 2 group than in the control group, and MTA Fillapex was more cytotoxic than AH-Plus. There were more apoptotic cells in the MTA Fillapex and AH-Plus groups than in the other groups at 3 h (P<0.001). CONCLUSION: GuttaFlow sealers are less cytotoxic than MTA Fillapex and AH-Plus. At all experimental time points, there was no significant difference in the cell viability between the GuttaFlow Bioseal group and the control group.

Bond strength of self-adhesive resin cement to root dentin. Comparison of photon-initiated photoacoustic streaming technique with needle and ultrasonic irrigation.

OBJECTIVE: The aim of this study was to investigate the effects of photon-initiated photoacoustic streaming (PIPS) with various irrigating solutions on the bond strength of a self-adhesive resin cement to root dentin. MATERIALS AND METHODS: Seventy-two mandibular premolar roots were divided into six groups after post space preparation and treated with a needle irrigation with distilled water and NaOCl, ultrasonic irrigation with NaOCl, PIPS with NaOCl, PIPS with EDTA and PIPS with distilled water at 0.3 W, 15 Hz and 20 mJ per pulse for 60 s. Fiber posts were cemented with a newly marketed, self-adhesive resin cement. The data obtained from the push-out tests were analyzed using analysis of variance (ANOVA) and LSD post-hoc tests (p = 0.05). RESULTS: PIPS with distilled water resulted in higher push-out values than those of needle (with both distilled water and NaOCl) and ultrasonic irrigation (p < 0.05). CONCLUSIONS: The use of PIPS may provide higher bond strength of self-adhesive resin cement to root dentin than needle and ultrasonic irrigation techniques.

Evaluation of Apically Extruded Debris and Irrigant Produced by Different Nickel-Titanium Instrument Systems in Primary Teeth.

AIM: The purpose of this study was to determine the amount of extruded debris and irrigant associated with different single-file systems and one multiple-file system. MATERIALS AND METHODS: Forty-five newly extracted single rooted primary canine teeth were used in this study. The root canals were instrumented using the reciprocating single-file system, the single-file rotary system and the multiple-file rotary system. A 10(-6) precision micro-balance was used to calculate the amount of extruded debris and irrigant. The incubation period was set as 15 days at 37°C to obtain dry debris. The preparation time for instrumentation was also recorded. The data were statistically analyzed by Manova and Bonferroni adjustment. RESULTS: Considering the apically extruded debris, while there was statistically significant difference between Reciproc and OneShape groups (p < 0.05), no statistically significant difference was found among the other groups (p > 0.05). In terms of irrigation solution, although significant difference was obtained between the Reciproc and other two groups (p < 0.05), no statistically significant difference was obtained between the two rotary instruments (p > 0.05). Instrumentation was significantly faster using Reciproc than with all other instrument (p < 0.05). CONCLUSION: All systems caused apical debris and irrigant extrusion. Full-sequences rotary instrumentation systems may be preferable for preparation primary teeth. CLINICAL SIGNIFICANCE: This is the first study carrying out to compare both apical debris and irrigation solution extrusion with reciprocal and rotary single-file systems with other preparation systems in primary teeth.

Effect of various intracanal medicaments on the bond strength of self-adhesive resin cement to root canal dentin.

Objective: It has been shown that the irrigating solutions and medicament used during root canal treatment may affect the bonding strength. The aim of this study was to evaluate the effect of triple antibiotic paste (TAP), double antibiotic paste (DAP) and calcium hydroxide (CH) on the bond strength to root dentin of self-adhesive resin cement. Materials and methods: Forty-eight single-rooted human teeth were prepared and randomly divided into one control and three experimental groups (dressing with TAP, DAP or CH). After removal of intracanal dressing, post-spaces were created and fiber posts cemented to the root canal using a self-adhesive resin cement. A push-out test was performed. The data obtained from the push-out test were analyzed using analysis of variance and Bonferroni post hoc tests (p = 0.05). Results: TAP decreased the bond strength of self-adhesive resin cement bond strength to root dentin compared to the control group (p = 0.012), while CH and DAP did not influence this (p > 0.05). The majority of specimens exhibited adhesive failures. Conclusions: TAP decreased the bond strength of self-adhesive to the root dentin compared to the control group.

Effect of PIPS technique at different power settings on irrigating solution extrusion.

The aim of this study was to determine the effect of photon-induced photoacoustic streaming (PIPS) technique at different power settings on extrusion of irrigating solution. Root canal preparation was performed up to a #30 file on 64 extracted single-rooted mandibular premolar teeth, which were then divided into four groups. Each group was irrigated with one of the following irrigation methods: (a) irrigation with conventional irrigation open-ended needles, (b) continuous ultrasonic irrigation, (c) 0.3 W PIPS, or (d) 0.9 W PIPS. Apical extrusion of irrigating solution was evaluated using a modified model. The net weight of the extruded irrigating solution was measured for each group, and the resulting data were analysed statistically using Kruskal-Wallis at a 95 % confidence level (P < 0.05). Although the 0.9 W PIPS group resulted in the largest quantity of irrigation solution, the ultrasonic group was the smallest. However, the difference between these groups was not statistically significant at the 95 % level of confidence (P > 0.05). PIPS at both 0.3 W and 0.9 W resulted similar solution extrusion to the conventional irrigation or ultrasonic irrigation.

Assessment of apically extruded debris and irrigant produced by different nickel-titanium instrument systems.

The aim of this study was to evaluate the preparation time and the amounts of apically extruded debris and irrigant using different nickel-titanium instrumentation systems. Forty-five extracted single-rooted mandibular premolar teeth were selected and divided into three groups. The root canals were instrumented according to the manufacturers' instructions, using a reciprocating single-file system, a single-file rotary system and a multiple-file rotary system. Bidistilled water was used as the irrigant solution. The apically extruded debris and irrigant were collected into preweighed Eppendorf tubes. The amounts of extruded debris and irrigant were assessed with a precision micro-balance. The Eppendorf tubes were incubated at 37°C for 15 days. After the incubation period, they were weighed again to assess the debris extrusion. The time required to prepare the canals was also recorded. The results were statistically analyzed using MANOVA and Bonferroni's adjustment. Considering the apically extruded debris and irrigant, there were no statistically significant differences among the groups (p > 0.05). The Reciproc group produced the highest debris (0.000632 ± 0.000162 gr) and irrigant (0.844587 ± 0.437814 ml) extrusion values. While the least extruded debris was observed with OneShape (0,000431 ± 0,000171 gr), the least extruded irrigant was observed with ProTaper system (0.564147 ± 0.370596 ml). Instrumentation was faster using the Reciproc than the other two instruments (70.27 ± 13.38 s) (p < 0.05). All of the instrumentation systems used in this study produced apical debris and irrigant extrusion. The reciprocating single-file system tended to produce more debris and irrigant extrusion, compared with the rotary systems. Considering the preparation time, the single-file systems appeared to be advantageous due to their working time.

Effects of root canal preparation, various filling techniques and retreatment after filling on vertical root fracture and crack formation.

AIM: To investigate the incidence of cracks in root dentin after rotary instrumentation and filling with cold lateral condensation (CL), single-cone obturation (SC), and warm vertical compaction (WV) and retreatment of each filling system. METHODOLOGY: One-hundred sixty mandibular incisors were selected. Twenty teeth were left unprepared and served as a control, and the remaining 140 teeth were instrumented. Twenty teeth were assigned to an only prepared group. The remaining 120 teeth were assigned to three root canal filling groups and three retreatment groups (n = 20), as follows: CL, WV, SC, and retreatment of each filling system. All the roots were sectioned perpendicular to the long axis at 2, 4, 6, and 8 mm from the apex, and the sections were then observed under a stereomicroscope. The absence/presence of cracks and vertical root fractures were recorded, and the data were analyzed with a Pearson's chi-square test (P = 0.05). RESULTS: No complete vertical root fractures were observed in the unprepared and only prepared groups. However, vertical fractures were observed in the filling and retreatment groups. There were significantly more cracks in the retreatment after WV group than the other groups, with the exception of the retreatment after SC, WV, and CL resulted in significantly more cracks than the only prepared and SC. CONCLUSIONS: The filling techniques (except SC) caused more cracks than preparation only. The SC caused fewer cracks compared to the other filling techniques. The retreatment following the different filling techniques (except CL) caused more cracks than the original fillings.

Bleaching effect of activation of hydrogen peroxide using photon-initiated photoacoustic streaming technique.

OBJECTIVES: This study aims to investigate the bleaching effectiveness of photon-initiated photoacoustic streaming (PIPS) using 35 % hydrogen peroxide on discolored teeth as compared with different devital bleaching techniques. MATERIALS AND METHODS: Fifty extracted human mandibular incisors were collected and artificially stained using sheep's blood. The teeth were then randomly divided into five groups according to the different bleaching procedures to be tested: walking bleach with sodium perborate and with 35 % hydrogen peroxide gel, both for 1 week; PIPS using 35 % hydrogen peroxide liquid for 30 min; and just 35 % hydrogen peroxide, as a liquid and as a gel (again, for 30 min). Spectrophotometric measurements were obtained on the buccal surfaces of the crowns, at the beginning, just after the bleaching procedures had been performed, and the following first, third, and seventh days. The ∆E values were calculated, and the data were analyzed with a two-way analysis of variance (P = 0.05). RESULTS: There were statistically significant differences between the PIPS technique using 35 % hydrogen peroxide liquid and the 35 % hydrogen peroxide liquid and gel without PIPS immediately after the procedures (P < 0.05). On Days 1, 3, and 7, the PIPS technique further bleached specimens more than all of the other techniques (P < 0.05). CONCLUSIONS: The PIPS technique using 35 % hydrogen peroxide was found to be more effective than all of the conventional techniques. CLINICAL RELEVANCE: Within limitations of this study, PIPS technique using hydrogen peroxide was superior to the conventional techniques. Further studies should be conducted to determine if the PIPS technique results in any complications, particularly cervical resorption.

The effect of medicaments used in endodontic regeneration technique on the dislocation resistance of mineral trioxide aggregate to root canal dentin.

INTRODUCTION: The aim of this study was to evaluate the effect of calcium hydroxide (CH) and antibiotic pastes, including a mixture of metronidazole and ciprofloxacin, with and without minocycline or cefaclor, on the dislocation resistance of mineral trioxide aggregate (MTA) to root dentin. METHODS: Eighty single-rooted human mandibular premolars were selected. The teeth were prepared by using the ProTaper system. The prepared teeth were then instrumented to a #6 Peeso reamer to obtain a standard internal diameter of 1.5 mm. The reamers were passed 1 mm beyond apex to simulate immature teeth. The specimens were then randomly divided into a control group (no intracanal medicament was used) and 4 experimental groups that were treated with an intracanal medicament: CH, double antibiotic paste (DAP) with metronidazole and ciprofloxacin, triple antibiotic paste (TAP) with minocycline, or TAP with cefaclor (n = 16). After 3 weeks, the medicaments were removed, and approximately 3 mm of MTA was placed in the coronal third of the canals. A push-out test was used to measure the dislocation resistance between the root dentin and MTA. Data were analyzed by using one-way analysis of variance and Tukey post hoc tests. RESULTS: The dislocation resistance values of the CH, TAP with minocycline, and TAP with cefaclor groups were similar to those of the control group (P > .05), whereas the DAP group had the lowest dislocation resistance when compared with the other groups (P < .05). Overall, there was a predominance of cohesive failures between root dentin and MTA. CONCLUSIONS: The results of this study indicate that the application of DAP as an intracanal medicament reduced the dislocation resistance of MTA to root dentin.

Evaluation of effectiveness of various irrigating solutions on removal of calcium hydroxide mixed with 2% chlorhexidine gel and detection of orange-brown precipitate after removal.

INTRODUCTION: The aims of the present study were to evaluate the effect of various irrigating solutions on the removal of calcium hydroxide mixed with 2% chlorhexidine gel from an artificial groove created in a root canal and the generation of orange-brown precipitate in the remaining calcium hydroxide mixed with 2% chlorhexidine gel after irrigation with the various irrigating solutions. METHODS: The root canals of 48 mandibular premolars were prepared using ProTaper Universal Rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F4. The roots were split longitudinally, and a standardized groove was prepared in the apical part of 1 segment. The root halves were reassembled, and calcium hydroxide mixed with 2% chlorhexidine gel medicament was placed into the grooves. The roots were randomly divided into 4 experimental groups specified by the irrigation solution used: 1% NaOCl, 17% EDTA, 7% maleic acid, and 10% citric acid (n = 12). The amount of remaining medicament was evaluated under a stereomicroscope using a 4-grade scoring system. After irrigation, the specimens were also evaluated for the presence/absence of orange-brown precipitate. The effects of the different irrigation solutions on medicament removal were statistically evaluated using the Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction at a 95% confidence level (P = .0083). RESULTS: Solutions of 7% maleic acid and 10% citric acid were superior to solutions of 1% NaOCl and 17% EDTA in removing calcium hydroxide mixed with 2% chlorhexidine gel (P < .0083). There were no significant differences among the other groups (P > .0083). Orange-brown precipitate was observed in all specimens of the NaOCl group but in no specimens in the other groups. CONCLUSIONS: Irrigation solutions of 7% maleic acid and 10% citric acid were more effective in the removal of calcium hydroxide mixed with 2% chlorhexidine gel than those of 1% NaOCl and 17% EDTA. Orange-brown precipitate was found in all specimens of the NaOCl-irrigated groups. However, the precipitate was not observed in specimens in the groups irrigated with 17% EDTA, 7% maleic acid, and 10% citric acid.

Effect of photo-activated disinfection on bond strength of three different root canal sealers.

INTRODUCTION: The aim of this in vitro study was to evaluate the bond strength of Photo-Activated Disinfection (PAD) system to dentin with different root canal sealers by using a push-out test design. MATERIALS AND METHODS: A total of 30 extracted mandibular premolar teeth with single and straight roots were used. The crowns were removed and the root canals were prepared by using ProTaper rotary files. The smear layer was removed and the roots were randomly divided into two groups (n = 15) according to the use of PAD system as the final disinfecting agent. Each group was then divided into 6 (n = 5) subgroups and obturated with gutta-percha and 3 different root canal sealers. The groups were Group 1: Sodium hypochlorite (NaOCl) + ethylenediaminetetraacetic acid (EDTA)-AH Plus sealer; Group 2: NaOCl + EDTA + PAD-AH Plus; Group 3: NaOCl + EDTA-Sealapex; Group 4: NaOCl + EDTA + PAD-Sealapex; Group 5: NaOCl + EDTA-mineral trioxide aggregate (MTA)-Fiallapex; and Group 6: NaOCl + EDTA + PAD-MTA-Fillapex. 1-mm thickness horizontal sections (n: 5 × 4 = 20) were sliced for the push-out bond strength measurement. RESULTS: Group 3 and 4 showed significantly lower bond strengths compared with all the other groups (P < 0.05). No statistically significant difference was found among Groups 1, 2 and 5, but there was statistically significant difference between Group 5 and 6 (P < 0.05). CONCLUSION: This in vitro study indicated that the PAD system adversely affected the bond strength of the MTA Fillapex root canal sealer.

Assessment of apically extruded debris and irrigant produced by different nickel-titanium instrument systems

The aim of this study was to evaluate the preparation time and the amounts of apically extruded debris and irrigant using different nickel-titanium instrumentation systems. Forty-five extracted single-rooted mandibular premolar teeth were selected and divided into three groups. The root canals were instrumented according to the manufacturers’ instructions, using a reciprocating single-file system, a single-file rotary system and a multiple-file rotary system. Bidistilled water was used as the irrigant solution. The apically extruded debris and irrigant were collected into preweighed Eppendorf tubes. The amounts of extruded debris and irrigant were assessed with a precision micro-balance. The Eppendorf tubes were incubated at 37°C for 15 days. After the incubation period, they were weighed again to assess the debris extrusion. The time required to prepare the canals was also recorded. The results were statistically analyzed using MANOVA and Bonferroni’s adjustment. Considering the apically extruded debris and irrigant, there were no statistically significant differences among the groups (p > 0.05). The Reciproc group produced the highest debris (0.000632 ± 0.000162 gr) and irrigant (0.844587 ± 0.437814 ml) extrusion values. While the least extruded debris was observed with OneShape (0,000431 ± 0,000171 gr), the least extruded irrigant was observed with ProTaper system (0.564147 ± 0.370596 ml). Instrumentation was faster using the Reciproc than the other two instruments (70.27 ± 13.38 s) (p < 0.05). All of the instrumentation systems used in this study produced apical debris and irrigant extrusion. The reciprocating single-file system tended to produce more debris and irrigant extrusion, compared with the rotary systems. Considering the preparation time, the single-file systems appeared to be advantageous due to their working time.

Effect of photoactivated disinfection on bond strength of root canal filling.

INTRODUCTION: The aim of this in vitro study was to assess and compare the effect of photoactivated disinfection (PAD) on the bond strength of root canal sealers to human root canal dentin using the push-out test. METHODS: Fifteen extracted human mandibular premolar teeth with single and straight roots were used. After the clinical crowns were removed from the cementoenamel junction, root canals were prepared with the ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) rotary system to the size of the F3 file. The smear layer of the roots was removed using 17% EDTA followed by 5.25% sodium hypochlorite (NaOCl) and distillate water. The roots were then randomly divided into 3 groups (n = 5) according to the final irrigation regimen. In group 1, PAD (FotoSan; CMS Dental, Copenhagen, Denmark) was applied to the root canals and light cured for 20 seconds. Group 2 was finally irrigated with a 2% solution of chlorhexidine gluconate, and group 3 served as the control group (NaOCl + EDTA). All the canals were then obturated with the lateral condensation technique using gutta-percha and AH Plus sealer (Dentsply Maillefer) sealer. One-millimeter-thick horizontal sections from the coronal and midthirds of each root (n: 5 × 4 = 20) were sliced for the push-out bond strength measurement. The data were converted to megapascals and statistically analyzed using 1-way analysis of variance and the post hoc Tukey test. RESULTS: There was no significant difference among the bond strength of PAD, chlorhexidine gluconate, and NaOCl (P > .05). CONCLUSIONS: We conclude that PAD does not adversely affect the bond strength of the AH Plus sealer to root canal dentin and that it can be used for the final disinfection of root canals.