Ali Keles

Removal of Filling Materials from Oval-shaped Canals Using Laser Irradiation: A Micro–computed Tomographic Study

INTRODUCTION The aim of this study was to assess the efficacy of lasers in removing filling remnants from oval-shaped canals after retreatment procedures with rotary instruments using micro-computed tomographic imaging. METHODS The root canals of 42 mandibular canines were prepared and obturated using the warm vertical compaction technique. Retreatment was performed with rotary instruments, and the specimens were distributed in 3 groups (n = 14) according to the laser device used in a later stage of retreatment procedure: Er:YAG, Er:YAG laser-based photon-induced photoacoustic streaming, and Nd:YAG. The specimens were scanned in a micro-computed tomographic device after root canal filling and each stage of retreatment at a resolution of 13.68 μm. The percentage differences of the remaining filling material before and after laser application within and between groups were statistically compared using the paired sample t test and 1-way analysis of variance test, respectively. Significance level was set at 5%. RESULTS Overall, filling residues were located mainly in the apical third and into canal irregularities after the retreatment procedures. After using rotary instruments, the mean percentage volume of the filling remnants ranged from 13%-16%, with no statistical significant difference between groups (P > .05). Within groups, additional laser application had a significant reduction in the amount of the remaining filling materials (P < .05). A comparison between groups showed that Er:YAG laser application after the use of rotary instruments had a significantly higher removal of filling remnants (~13%) than Er:YAG laser-based photon-induced photoacoustic streaming (~4%) and Nd:YAG (~3%) (P < .05). CONCLUSIONS None of the retreatment procedures completely removed the filling materials. The additional use of lasers improved the removal of filling material after the retreatment procedure with rotary instruments.

Micro-computed tomography and histomorphometric analysis of the effects of platelet-rich fibrin on bone regeneration in the rabbit calvarium

OBJECTIVE The present study aimed to investigate the effectiveness of platelet-rich fibrin (PRF) on bone regeneration when used alone or in combination with hydroxyapatite (HA)/beta-tricalcium phosphate (βTCP). DESIGN In this study, 20 New Zealand white rabbits were used and four calvarial defects were prepared in each animal. PRF, Straumann(®) Bone Ceramic (SBC), or PRF+SBC was applied to the defects; one defect was left untreated as a control. Ten rabbits were sacrificed at week 4 (T1) and 10 at week 8 (T2). After micro-computed tomography (micro-CT) scanning, the samples were sent for histological and histomorphometric analysis to evaluate and compare the volume and area of regenerated bone. RESULTS Histomorphometric and micro-CT analysis showed that both PRF and SBC significantly increased bone regeneration at T1 and T2 (P<0.01). When PRF was used in combination with HA/βTCP, a further significant increase in new bone formation was observed at T1 and T2 compared with that when PRF or SBC was used alone (P<0.01). CONCLUSIONS PRF has a positive effect on bone formation when used alone and in combination with HA/βTCP.

Effectiveness of different irrigation systems on smear layer removal: A scanning electron microscopic study

Objectives: To evaluate effectiveness of the apical negative pressure irrigation (EndoVac), passive ultrasonic irrigation (PUI), and conventional needle irrigation (CI) systems on smear layer (SR) removal. Materials and Methods: Sixty single-rooted canines were prepared using NiTi rotary files and subjected to different irrigation regimens: EndoVac with NaOCl (Group 1) or NaOCl/EDTA (Group 2); PUI with NaOCl (Group 3) or NaOCl/EDTA (Group 4); CI with NaOCl (Group 5) or NaOCl/EDTA (Group 6). The roots were split longitudinally. SEM images were taken to evaluate the amount of residual SR. Results: In Groups 1, 3, and 5, there was no removal of SR (P > 0.05). The coronal thirds within Groups 2, 4, and 6 were cleaned completely, but the middle and the apical thirds was achieved partially or completely (P > 0.05). Conclusion: Regardless of which irrigation system was used, the use of NaOCl alone failed to remove the SR. In NaOCl/EDTA combination groups, the SR was removed partially or completely and no statistical significance. This study demonstrated that in order to remove the SR should be used EDTA solution for final irrigation in the root canal, regardless of the technique in each of the three.

Quality of different gutta-percha techniques when filling experimental internal resorptive cavities: a micro-computed tomography study.

The purpose of this ex vivo study was to determine the quality of root fillings in experimental internal resorptive cavities filled using cold lateral condensation (CLC), vertical condensation and Thermafil techniques. Forty-five extracted maxillary canine teeth were selected. After root canal instrumentation, the roots were sectioned horizontally and experimental internal resorption cavities were prepared. The root sections were re-approximated with a luting agent and randomly assigned to three groups (n = 15) to be filled using CLC, vertical condensation and Thermafil, respectively. Assessment of obturation quality in the internal resorptive cavity was performed using a desktop X-ray micro focus computed tomography scanner, and the percentage of gutta-percha (GP), sealer and voiding was calculated for each specimen. Data were statistically analysed using non-parametric tests, with P < 0.05 denoting a statistically significant difference. Vertical condensation filled 96.25 ± 8.31% of the total artificial cavity, and was superior to CLC (63.20 ± 16.87%) and Thermafil (59.26 ± 18.47%). The mean percentage of voids was 3.75 ± 8.31% in the vertical condensation group, 37.09 ± 17.13% in the CLC group and 41.06 ± 18.60% in the Thermafil group. We conclude that obturation of experimental resorption cavities is significantly better when using vertical condensation than when using other GP-based techniques.

Comparative analysis of three different filling techniques and the effects of experimental internal resorptive cavities on apical microleakage

Objectives: The aim of this study was to evaluate the sealing abilities of three different gutta-percha techniques in experimentally defective roots (EDR) and non-defective roots (NR). Materials and Methods: Sixty canine teeth were divided into six groups of ten; Group 1, NR + cold lateral condensation (CLC); Group 2, EDR + LC; Group 3, NR + BeeFill; Group 4, EDR + BeeFill; Group 5, NR + Thermafil; and Group 6, EDR + Thermafil. Apical leakage was measured using a computerized fluid filtration meter with a laser system. Results : Statistical analysis revealed that the CLC demonstrated more microleakage in the EDR than in the NR (P < 0.01). Thermafil demonstrated more microleakage in the NR than in the EDR (P < 0.01). No statistically significant differences were found between the BeeFill groups (P > 0.05). Conclusions: The results of this study indicate that internal resorptive cavities can affect the apical sealing properties of different root canal filling techniques, with Thermafil ensuring the lowest apical microleakage.

Comparative evaluation of root canal preparations of maxillary first molars with self‐adjusting file, reciproc single file, and revo‐s rotary file: A micro‐computed tomography study

This study was aimed to use micro-computed tomography (μ-CT) to evaluate the canal shaping properties of three nickel-titanium instruments, Self-Adjusting File (SAF), Reciproc, and Revo-S rotary file, in maxillary first molars. Thirty maxillary molars were scanned preoperatively by using micro-computed tomography (μ-CT) scans at 13,68 μm resolution. The teeth were randomly assigned to three groups (n = 10). The root canals were shaped with SAF, Reciproc, and Revo-S, respectively. The shaped root canals were rescanned. Changes in canal volumes and surface areas were compared with preoperative values. The data were analyzed using Kruskal-Wallis and Conovers post hoc tests, with p < .05 denoting a statistically significant difference. Preoperatively canal volumes and surface area were statistically similar among the three groups (p > .05). There were statistically significant differences in all measures comparing preoperative and postoperative canal models (p = 0.0001). These differences occurred after instrumentation among the three experimental groups showed no statistically significant difference for volume (p > .05). Surface area showed the similar activity in buccal canals in each of the three techniques whereas no statistically significant difference was detected among surface area, the SAF, and the Revo-S in the palatal (P) canal. Each of three shaping system showed the similar volume activity in all canals, but SAF and Revo-S provided more effectively root planning in comparison with Reciproc in P canal.

Endodontic treatment of hypertaurodontism with multiple bilateral taurodontism

The term taurodontism is derived from the Latin word tauros, for “bull,” and the Greek term odus, for “tooth,” or “bull tooth.” Taurodontism is a morpho-anatomical developmental anomaly, which is seen infrequently in teeth only. It is characterized by a deficiency in the constriction at the cement-enamel junction, with lengthened pulp chambers and apical displacement of the pulpal floor. This gives the tooth a quadrilateral or cylindrical look. This report presents a case of multiple bilateral taurodontism and the successful endodontic treatment of the tooth that had hypertaurodontism. A male patient was referred to the endodontic clinic with decayed left maxillary first molar. Hypertaurodontism was confirmed after clinical and radiographic examination. Panaromic X-rays revealed that all of the patients molar teeth were taurodontic. Taurodontism offers challenges to the practitioner during shaping and disinfection and at the time of filling the root canals.

Multidisciplinary treatment approach for horizontal root fractures

The aim of this case report is to present a multidisciplinary treatment plan for horizontal root fracture of maxillary anterior teeth that resulted from trauma. A 16-year-old male presented a horizontal root fracture in the middle-third of teeth 11 and 21. Dislocated tooth fragments were repositioned using a composite splint technique. Follow-up examinations revealed the teeth lost vitality after trauma. Separated tooth fragments were removed by a surgical operation and then reattached using fiber post and resin cement. Teeth were replanted into the alveolar socket and splinted after root canal treatment. After 1 year of follow-up examinations, this comprehensive treatment was observed to be successful both clinically and radiographically. Horizontal root fractures can be treated successfully by extraoral reattaching of fractured segments and intentional replantation of teeth after root canal treatment.

A comparison of the bond strength of different adhesive systems to dentin contaminated with chloroform

Aim: The purpose of this study was to evaluate the microtensile bond strengths of five different bonding agents to dentin contaminated with chloroform which cleaning the remnants of the root canal sealer in coronal access cavities of teeth. Materials and Methods: A total of 30 extracted human mandibular molar teeth were used for study. Teeth were sectioned with diamond bur to expose the superficial dentin. AH Plus as a root canal sealer was placed to exposed dentin surface. Teeth were stored at least for 5 min motionless for sealer set. More of sealer on the surface of teeth was taken with the help of cotton pellets. Dentin surface was treated with 0.1 mL of chloroform which was kept for 1 min. After that, surfaces of teeth were flushed with distilled water and dried. Teeth were separated randomly into five groups and Clearfil SE Bond, Futura Bond M, Adper Easy Bond, Clearfil S3 Bond, and Optibond FL bonding agents were applied according to manufacturer′s instructions. The specimens were sectioned parallel blocks approximately 1 mm thickness and 1 mm width. The specimens pasted apparatus and subjected to microtensile testing device with a crosshead speed of 1 mm/min. Connection surface of all samples was measured after the end of the test process. The connection types of surfaces were examined under a light microscope magnification Χ10. Results: There was no statistically significant difference between the Optibond FL and Adper Easy Bond. However, Adper Easy Bond gave higher binding than the other tested materials. There was no statistically difference among Optibond FL, Clearfil S3 Bond, and Clearfil SE Bond. Conclusions: Many endodontically treated teeth are lost due to poor restorative treatment of teeth. Endodontic treatment procedures will affect bonding agents, so it could result in failure of the restoration.

Effect of salivary contamination on micro-tensile bond strength of self-etch adhesives systems after bonding procedure

Aims: The purpose of this study was to evaluate the effect of saliva contamination on the micro-tensile bond strength (μTBS) of two self-etching (SE) adhesive systems (Clearfil SE Bond, Clearfil S3 Bond). Materials and Methods: Flat occlusal dentin surfaces were created on 12 extracted human third molar teeth. The two bonding systems and resin composite (Spectrum® TPH® 3) were bonded to the dentin under six surface conditions: Group 1: Tooth samples were randomly divided into three equal subgroups. Clearfil SE 1: This was a control group in which dentin was not contaminated with the saliva (primer/bonding/composite). Clearfil SE 2: Contaminated once (primer/bonding (cured)/saliva/rinsing/drying/primer/bonding/composite). Clearfil SE 3: The samples were contaminated 2 times (primer/bonding (cured)/saliva/rinsing/drying/primer/bonding (cured)/saliva/rinsing/drying/primer/bonding/composite). Group 2: The procedures for Group 2 were similar to Group 1 but did not contain a primer stage. Tooth samples were randomly divided into three equal subgroups (Clearfil S3 1, 2, and 3). After 24 h, the teeth were prepared for microtensile bond testing and tensile bond strength was measured (1 mm/min). The data were calculated as megapascal (MPa) and analyzed using the one-way ANOVA and Tukey′s post-hoc test (P < 0.05). Results: The μTBS of the Clearfil S3 3 subgroup was statistically higher than that of the Clearfil S3 2 subgroup and Clearfil S3 1 subgroup. There were no significant statistical differences in the μTBSs between the Clearfil S3 2 subgroup and the control subgroup. There were no statistical differences in μTBSs among the Clearfil SE subgroups. Conclusion: μTBS is not affected adversely from one or two saliva contamination after the bonding procedure.