Yakup Üstün

Push‐out bond strength of two new calcium silicate‐based endodontic sealers to root canal dentine

AIM To assess the push-out bond strength of two new calcium silicate-based endodontic sealers in the root canals of extracted teeth. METHODOLOGY Thirty extracted single-rooted central incisors of similar sizes were selected randomly and distributed to three groups (n = 10). All canals were instrumented using ProTaper rotary instruments to achieve tapered canal walls. Irrigation was performed using 5 mL 2.5% NaOCl between each instrument, and the smear layer was removed using 5 mL 17% EDTA. The canals were filled with three different sealers using a cold lateral compaction technique: group 1: AH Plus + gutta-percha, group 2: I Root SP + gutta-percha and group 3: MTA Fillapex + gutta-percha. Three horizontal sections were prepared at a thickness of 1 mm ± 0.1 in the apical, middle and coronal parts of each root. The test specimens were subjected to the push-out test method using a Universal Test Machine (Instron, Canton, MA, USA) that carried 1-mm, 0.5-mm and 0.3-mm plungers for coronal, middle and apical specimens, respectively. The loading speed was 1 mm min(-1) . The push-out data were analysed by two-way analysis of variance (anova) and the post hoc Holm-Sidak test, with significance set at P < 0.05. RESULTS In the coronal specimens, there was no significant difference between the sealers. In the middle and apical segments, there was no significant difference between I Root SP and AH Plus groups. However, the I Root SP and AH Plus had significantly higher bond strength values than the MTA Fillapex (P < 0.05). In terms of root segments, the bond strengths in the middle specimens and the apical specimens were higher compared with the bond strengths in the coronal specimens (P < 0.05). There were no significant differences between the bond strengths in the middle and apical specimens. CONCLUSION MTA Fillapex had the lowest push-out bond values to root dentine compared with other sealers.

Evaluation of apically extruded debris associated with several Ni-Ti systems.

AIM To evaluate the apical extrusion of debris associated with several root canal preparation systems in vitro. METHODOLOGY Forty-five extracted human mandibular premolars with single canals and similar lengths were used. The root canals were instrumented using ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland), Twisted File (SybronEndo, Orange, CA, USA) or WaveOne (Dentsply Maillefer, Ballaigues, Switzerland). Debris extruded apically during instrumentation was collected into pre-weighed Eppendorf tubes. The Eppendorf tubes were then stored in an incubator at 70 °C for 5 days. The Eppendorf tubes were weighed to obtain the final weight of the Eppendorf tubes plus extruded debris. Three consecutive weights were obtained for each tube. The groups were compared using the Kruskal-Wallis one-way analysis of variance on Ranks and Tukeys test. RESULTS The ProTaper Next group produced the highest mean extrusion value whilst WaveOne produced less debris compared with all the other instruments (P > 0.05). There was a significant difference between the ProTaper Next and WaveOne group (P < 0.05). CONCLUSIONS Apically extruded debris was associated with all instrumentation techniques. The WaveOne system extruded less debris compared with the Twisted File and ProTaper Next.

The effects of different nickel-titanium instruments on dentinal microcrack formations during root canal preparation.

Objective: The aim of the present study was to investigate the incidence of dentinal microcracks caused by different preparation techniques. Materials and Methods: 120 extracted human mandibular incisor teeth were divided into five experimental groups and one control group (n = 20): Group 1: Hand preparation with balanced force technique up to #25 K-file. Group 2: Preparation with only ProTaper F2 instrument in a reciprocating movement. Group 3: Preparation with Reciproc R25 instrument in a reciprocating movement. Group 4: Preparation with ProTaper instruments up to F2 instrument. Group 5: Preparation with ProTaper Next instruments up to X2 instrument. No procedure was applied to control group. The roots were sectioned horizontally at 3, 6 and 9 mm from the apex and examined. Absence or presence of dentinal microcracks was noted. Results: The Chi-square test was performed to compare the appearance of cracked roots between all groups. There were no significant differences among the groups (P > 0.05). Conclusions: In conclusion, except the hand file and control group, all experimental groups showed microcrack formations.

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.

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.

Effects of Zoledronic Acid on Healing of Mandibular Fractures: An Experimental Study in Rabbits

PURPOSE The purpose of the present study was to evaluate the effects of systemically administered zoledronic acid (ZA) on mandibular fracture healing in a rabbit model using radiodensitometric, biomechanical, histologic, and histomorphometric methods. MATERIALS AND METHODS A total of 36 skeletally mature male New Zealand white rabbits were used. The rabbits were randomly divided into 2 groups. A mandibular corpus fracture was created experimentally in all 36 rabbits. The experimental group was administered an intravenous, single dose of 0.1 mg/kg ZA, and the control group was administered only saline infusion during the procedure. All rabbits were sacrificed on the 21st postoperative day. Digital radiodensitometric analysis, a 3-point bending test, and histologic and histomorphometric examinations were performed on the harvested hemimandibles. The data were analyzed statistically. RESULTS Biomechanical testing data showed that ZA treatment resulted in a significant increase in the healed bone strength. This result was supported by the radiologic, histologic, and histomorphometric findings. CONCLUSIONS The results of the present study have revealed that systemic administration of ZA accelerates and improves the bone healing of mandibular fractures.

Outcomes of periradicular surgery of maxillary first molars using a vestibular approach: a prospective, clinical study with one year of follow-up.

PURPOSE The aim of the present prospective, randomized, controlled, clinical study was to compare the outcomes of periradicular surgery of the maxillary first molar tooth using the vestibular approach between 2 preoperative radiologic evaluation methods: cone beam computed tomography (CBCT) and conventional radiography. PATIENTS AND METHODS Periradicular surgery was applied to the maxillary first molar tooth in 40 patients. The patients were divided into 2 groups. The patients in group 1 underwent examination and preoperative planning with CBCT, and the patients in group 2 underwent examination and preoperative planning with conventional radiography. The outcomes of the treatment were evaluated radiographically and clinically, and the data were analyzed statistically. RESULTS The mean operative time was significantly shorter in group 1 than in group 2. According to the radiographic and clinical healing criteria used in the present study, the healing of patients in group 1 was rated as a success in 35%, an improvement in 40%, and a failure in 25%. In the group 2 patients, healing was rated as a success in 42.1%, an improvement in 31.6%, and a failure in 26.3%. Sinus membrane elevation was performed in 92.3% of all patients. Sinus membrane perforation occurred in 20% of the patients in group 1 and 36.8% of the patients in group 2. CONCLUSIONS Periradicular surgery of maxillary first molars using a vestibular approach is a viable treatment method with a low complication rate. Preoperative CBCT examination demonstrated positive contributions to the treatment outcomes.

Comparison of osteoconductive properties of three different β-tricalcium phosphate graft materials: a pilot histomorphometric study in a pig model.

AIMS The aim of this study was to compare the de novo bone formation ability and osteoconductive effects of three different β-tricalcium phosphate (β-TCP) graft materials. The micro-architectural parameters of the newly formed bone tissues were also compared among the different graft materials. MATERIAL AND METHODS Eight male Swiss domestic pigs were used in the study. Five bony defects were made with a trephine bur. Three of the defects were filled with Cerasorb®, Kasios® and Poresorb®. The fourth defect was filled with an autogenous bone graft. The last defect remained empty. All subjects were sacrificed after 8 weeks. RESULTS When compared to a negative control group, significant healing was observed in all the groups except the Cerasorb group. The osteoconductivity of the Poresorb group was better than that of the other groups (p < 0.05). The difference in the osteoconductivity of the Kasios and Cerasorb groups was statistically significant (p < 0.05). Comparison of the micro-architectural properties of newly formed bone tissues retrieved from the defects showed that those filled with Poresorb were the best. CONCLUSION β-TCP materials show different results in terms of the volume and characteristics of new bone formation, although they have a similar chemical structure.

The effect of reciprocation versus rotational movement on the incidence of root defects during retreatment procedures.

AIM To compare the incidence of dentinal defects caused by reciprocating and rotary techniques during retreatment procedures. METHODOLOGY One hundred and twenty extracted mandibular premolars with single canals were selected. Twenty teeth were left unprepared. The root canals in the remaining 100 teeth were prepared with K-files up to size 35 and filled with Gutta-percha and AH Plus sealer using a passive cold lateral compaction technique. Twenty canals were filled and received no further treatment. Eighty teeth were divided into four groups (n = 20 in each) to undergo the removal of the root filling. In groups 1 and 2, the root filling was removed using ProTaper Retreatment files and Reciproc files, respectively, and the canals were not refilled. In groups 3 and 4, the root filling was removed using ProTaper Retreatment files and Reciproc files, respectively, and the canals were then refilled using a conventional cold lateral compaction technique. The roots were sectioned horizontally at 3, 6 and 9 mm from the root apex and observed under a stereomicroscope at 20× magnification. Defects were categorized as no defect, incomplete defect and fracture. The differences between the groups were analysed using the chi-square exact test (P = 0.05). RESULTS No defects were observed in the unprepared and filled groups, in contrast to the experimental groups. In the coronal thirds, groups 2 and 4 had more dentinal defects than groups 1 and 3 (P < 0.05). In the middle thirds, group 4 had more defects than group 1 (P < 0.05). In the apical thirds, group 2 had fewer defects than did group 3 and group 4. Also, group 3 had more defects than group 1 (P < 0.05). When comparing the experimental groups, there were no significant differences with regard to fracture (P > 0.05). CONCLUSIONS Both nickel-titanium systems were associated with dentinal defects during retreatment procedures in extracted premolar teeth.

Diagnostic Concordance Characteristics of Oral Cavity Lesions

Purpose. The objective of this study was to evaluate the diagnostic concordance characteristics of oral cavity lesions by comparing the clinical diagnosis of the lesions with the histopathologic diagnosis. Material and Method. A retrospective analysis was conducted on the patients, who were admitted with oral cavity pathology and underwent biopsy procedure between 2007 and 2011. The oral cavity lesions were classified into 6 different groups as odontogenic cysts, nonodontogenic cysts, odontogenic tumors, nonodontogenic tumors, malignant tumors, and precancerous lesions in accordance with the 2005 WHO classification. The diagnoses were also recategorized into 3 groups expressing prognostic implications as benign, precancerous, and malignant. The initial clinical diagnoses were compared with the histopathologic diagnoses. Data were analyzed statistically. Results. A total of 2718 cases were included. Histopathologic diagnosis did not match the clinical diagnosis in 6.7% of the cases. Nonodontogenic tumors and malignant tumors had the highest misdiagnosis rates (11.5% and 9%, resp.), followed by odontogenic tumors (7.7%), precancerous lesions (6.9%), and odontogenic cysts (4.4%). Clinicians were excelled in diagnosis of benign and precancerous lesions in clinical setting. Conclusion. The detailed discordance characteristics for each specific lesion should be considered during oral pathology practice to provide early detection without delay.