Alper Kustarci

Effects of dentin surface treatments including Er,Cr:YSGG laser irradiation with different intensities on the push-out bond strength of the glass fiber posts to root dentin

Abstract Objective. Intra-canal post systems are commonly used to restore root-filled teeth. Bond strengths of the posts can be affected by various surface treatments of the post or the dentin. The aim of this study was to evaluate the effects of dentin surface treatments including erbium-chromium; yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation with different intensities on the push-out bond strength of the glass fiber posts to root dentin. Materials and methods. Forty single-rooted human maxillary incisors were filled and post spaces were prepared. After these procedures, the specimens were divided randomly into four groups according to the dentin surface treatments, as follows: (i) untreated surface (control), (ii) 1W Er,Cr:YSGG laser application, (iii) 2W Er,Cr:YSGG laser application and (iv) 3W Er,Cr:YSGG laser application. Then the posts were cemented into the root canals using dual-cured resin cement. Bonded specimens were cut into 1-mm-thick slices and push-out tests were performed using a universal testing device. All specimens were loaded until fracture and the failure modes were evaluated with a stereomicroscope at 32× magnification. Representative specimens were analyzed by scanning electron microscopy. Data were analyzed using a one-way ANOVA, Tukey and Wilcoxon tests. Results. The bond strength values ranged from 3.22–4.68 MPa. There were no statistically significant differences among the groups, regardless of the different levels. The coronal and middle levels of the post space had significantly higher bond strength values compared with the apical level (p < 0.05). Conclusion. Er,Cr:YSGG laser irradiation with different intensities did not increase the bond strength of the fiber posts to the root canal dentin walls.

Veneer Ceramic to Y‐TZP Bonding: Comparison of Different Surface Treatments

PURPOSE The purpose of this study was to evaluate the effects of various surface-treatment techniques for enhancing the bond strength between veneering ceramic and yttria-stabilized tetragonal zirconia polycrystals (Y-TZP). MATERIALS AND METHODS Pre-sintered Y-TZP specimens were divided into eight groups (n = 10) according to the surface-treatment technique used: (a) untreated (control); (b) air abrasion with aluminum oxide particles; (c) erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation at different energy intensities (1 to 6 W). All specimens were then sintered and veneered with veneering ceramic according to the manufacturers instructions. The obtained zirconia-ceramic specimens were immersed in 37°C distilled water for 24 hours before a shear bond strength test using a universal testing device at a 1 mm/min crosshead speed. The average values were calculated. After debonding, the Y-TZP surfaces were examined under a stereomicroscope to determine their fracture pattern, and the surface topography was evaluated with scanning electron microscopy after surface treatments. RESULTS The bond strength ranged from 13.24 to 20.54 MPa. All surface treatments increased the bond strength between the veneering ceramic and Y-TZP; however, the value for the 6 W irradiation group was significantly different from the values for other groups (p ˂ 0.05). CONCLUSIONS The present studys findings showed that higher energy densities were needed for the laser irradiation to improve the bond strength between the veneering ceramic and zirconia. CLINICAL IMPLICATION Y-TZP is commonly used as a core material in fixed restorations. The bond strength between zirconia and the veneering ceramic can be affected by various surface treatments.

The Influence of Various Irrigants on the Accuracy of 2 Electronic Apex Locators in Locating Simulated Root Perforations

Introduction: The aim of this study was to assess the accuracy of the Dentaport ZX (Morita Co, Kyoto, Japan) and the Rootor (Meta Biomed, Cheongwon‐gun, Korea) electronic apex locators (EALs) in detecting root perforations in dry conditions and in the presence of the following irrigation solutions: 2.5% sodium hypochlorite (NaOCl), 0.9% saline solution (NaCl), and 17% EDTA. Methods: Twenty extracted, single‐rooted human teeth were perforated artificially in the middle section. The actual canal lengths (ALs) up to the perforation site were determined, and then the teeth were embedded in an alginate mold. The electronic measurements of the perforations were obtained using a size 20 K‐file by each EAL in various conditions. For each tooth, the AL was subtracted from the electronic length of the perforation. Statistical analyses were performed using the Friedman and Wilcoxon signed rank tests at a significance level of P < .05. Results: The most accurate measurements for both EALs were obtained in dry conditions. Among the irrigation solutions in the Dentaport ZX group, EDTA gave the most accurate results, and NaOCl gave the least accurate ones. However, measurements with NaCl were closer to the AL than those obtained with EDTA for the Rootor group. Significant differences were noted among the EALs when the measurements were taken with NaOCl, NaCl, and EDTA (P < .05). Conclusions: The Dentaport ZX was more accurate compared with the Rootor in the presence of different irrigants. The content of the root canal affected the accuracy of both EALs. The most accurate measurements were obtained in dry canals. HighlightsThe Dentaport ZX and Rootor apex locators (EALs) detected the root canal perforations within a range of clinically acceptable variations in all conditions.The Dentaport ZX was more accurate compared with the Rootor in the presence of NaOCl, NaCl, and EDTA.The content of the root canal affected the accuracy of the measurements obtained by both EALs. The most accurate measurements were obtained in dry canals.

Surface roughness and morphologic changes of zirconia: Effect of different surface treatment

PURPOSE The purpose of this study was to investigate the surface roughness and morphologic changes of pre-sintered ZrO 2 after sandblasting and erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser application of different intensities. MATERIAL AND METHODS Eighty pre-sintered ZrO 2 cylinders (7 mm diameter, 3 mm height) were prepared and divided into eight groups. Specimens in the control group were not treated. The following treatments were applied: Er, Cr: YSGG laser irradiation with different energy intensities (1-6 W at 20 Hz, with air-water cooling proportion of 65%/55%) and air abrasion with Al 2 O 3 particles (120 μm). Then, all the specimens were sintered. The average surface roughness of each specimen was determined with a profilometer, and the morphology changes of a specimen from each group were evaluated with scanning electron microscope (SEM) analyses. The surface roughness data were analyzed through one-way analysis of variance and Tukeys honestly significant difference test (P < 0.05). RESULTS There were significant differences between 2 and 6 W irradiations and control group. The highest surface roughness value was obtained with 6 W irradiation (8.14 ± 1.26 Ra), followed by the 5 W (7.60 ± 1.12 Ra), 4 W (7.50 ± 0.90 Ra), 3 W (5.86 ± 1.03 Ra), 2 W (4.54 ± 0.53 Ra) and sandblasting group (2.18 ± 0.92 Ra). 1 W laser irradiation (0.80 ± 0.06 Ra) presented Ra values similar to the control group (0.77 ± 0.03). CONCLUSION The result of the statistical analyses and SEM images showed that Er, Cr: YSGG laser irradiation with 4-6 W/20 Hz presented significantly effect in surface roughness changes of zirconia than other surface treatments.

Pulp tissue dissolution capacity of QMix 2in1 irrigation solution.

Objective: The aim of this study was to evaluate the tissue dissolution efficacy of four root canal irrigation solutions (sodium hypochlorite [NaOCl], chlorhexidine gluconate [CHX], Octenidine [OCT], and QMix 2in1) on bovine pulp tissue. Materials and Methods: Fifty bovine pulp tissue samples, each weighing 6.55 mg, were prepared and randomly divided into four experimental groups and one control group (n = 10) according to the dissolution irrigants used: (1) 5.25% NaOCl group; (2) 2% CHX group; (3) OCT group; (4) QMix 2in1 group; and (5) control group (saline solution). These samples were then placed into special bovine dentin reservoir models and immersed for 1 h with each test solution (0.1 mL of each) at room temperature. The pulp samples were then blotted dry and weighed again. The percentage of weight loss was calculated. Statistically analyzed with one-way analysis of variance and post-hoc Tukey tests (P = 0.05). Results: Saline solution did not dissolve the bovine pulp tissue. All groups, except OCT, dissolved pulp samples more effectively than the control group (P < 0.05). The highest tissue dissolution was observed in 5.25% NaOCl group (P < 0.05). No statistically significant difference was found between the tissue-dissolving effect between QMix 2in1 and those of 2% CHX. Conclusions: Within the limitations of this in vitro study, NaOCl exhibited the best tissue-dissolving effect out of all solutions tested. CHX and QMix 2in1 were able to dissolve pulp tissue but less than NaOCl. OCT and saline solutions could not exhibit significantly tissue-dissolving effectiveness. This study shown that QMix 2in1 has little capacity to dissolve pulp tissue therefore used alone is not sufficient for this purpose.

Effects of Ozone and Photo‑Activated Disinfection against Enterococcus faecalis Biofilms In Vitro

OBJECTIVES The purpose of this study was to compare the antibacterial effects of gaseous ozone (O3) and photo-activated disinfection (PAD) methods against Enterococcus faecalis (E. faecalis) biofilms. MATERIALS AND METHODS Sixty-five human mandibular premolars with straight root canals were selected. After root canal preparation, the samples were sterilized and placed into eppendorf tubes with 1 mL brain heart infusion broth containing 1.5×10(8) colony-forming units (CFUs)/mL of E. faecalis. The contaminated samples were then divided into four groups (n=15) according to the disinfection method used: Group 1, Saline (positive control); Group 2, NaOCl (negative control); Group 3, Gaseous O3; and Group 4, PAD. Three non-contaminated teeth were used to control the infection and sterilization process. The CFUs were counted and the data were analyzed statistically. RESULTS There was a statistically significant difference between the experimental and control groups (P<0.05). The saline group had the highest number of remaining microorganisms. Complete sterilization was achieved in the 2.5% NaOCl group. There were no statistically differences between PAD and gaseous O3 (P>0.05). CONCLUSION Both PAD and gaseous O3 have a significant antibacterial effect on infected root canals. However, 2.5% NaOCl was superior in terms of its antimicrobial abilities compared with the other disinfection procedures.

In vitro comparison of four different electronic apex locators to determine the major foramen using the clearing technique

OBJECTIVES The aim of this study was to evaluate the accuracy of four electronic apex locators (EALs) (DentaPort ZX, Raypex 5, Endo Master and VDW Gold) in detecting the major foramen using the clearing technique. MATERIALS AND METHODS Forty-eight extracted single-rooted extracted teeth with mature apices were used for the study and divided into four groups of 12 teeth each. All teeth were embedded in an alginate model. Electronic measurements were taken using a size 15 K-file attached to the holder. Then, the teeth were cleared and photographed under a stereomicroscope with a digital camera. The distance between the tip of the file and the major foramen was measured by using an image analysis software program. Positive and negative values were recorded when the file tip was beyond or short of the major foramen and zero value when the file tip and the major foramen coincided. Statistical analysis was performed using the Kruskal-Wallis and Chi-square tests at a significance level of 0.05. RESULTS Mean distance from the file tip to the major foramen were 0.302 ± 0.202, 0.065 ± 0.293, 0.117 ± 0.475, and 0.258 ± 0.160 mm in the DentaPort ZX, Raype 5, Endo Master, and VDW Gold groups, respectively. There were no statistically significant differences among the devices (P > 0.05) . CONCLUSION Under the experimental conditions, all EALs showed an acceptable determination of the major foramen.

Evaluation of Various Pretreatments to Fiber Post on the Push-out Bond Strength of Root Canal Dentin

Introduction: The aim of this in vitro study was to compare the effect of different pretreatments (fiber post) with the laser‐activated irrigation (LAI) technique (for removal of the smear layer) on root canal dentin in terms of push‐out bond strength (PBS) in a fiber post. Methods: Fifty freshly extracted mandibular single‐rooted premolars were prepared, and LAI was applied to all roots (17% EDTA was 5 mL for 120 seconds with an erbium, chromium:yttrium‐scandium‐gallium‐garnet laser [0.50 W, 20 Hz, 25 mJ]). In addition, 50 quartz fiber posts were randomly assigned to 5 groups (n = 10) according to the surface treatments as follows: group S (sandblasting), group N1 and group N2 (neodymium:yttrium‐aluminum‐garnet laser irradiation [2 W, 200 mJ, 10 Hz, with pulse durations of 180 or 320 microseconds), group HF (9.7% hydrofluoric acid etched), and group C (control with no treatment). Dual‐cure resin cement was adhered onto the fiber posts after they were covered with a silane agent, and then the posts were placed into the canal space using a Lentulo spiral. The PBS test was performed after all specimens were transversally sectioned (root slices of 1‐mm thickness). Data were analyzed with 1‐way analysis of variance/Tukey post hoc test (&agr; = 0.05). Results: The highest PBS value was observed in group S (middle part), and the lowest value was observed in group C (apical part). There were no statistical differences among the groups regardless of the part. Furthermore, when the PBS values of the different parts of dentin were compared within treated groups, significant differences were observed in all groups except group N2 (P < .05). Conclusions: Within the limitations of this study, it can be concluded that the LAI technique when used with 17% EDTA had a significant effect on the amount of smear layer removed from the root canal dentin, which was also detected in the fracture pattern (adhesive failure [resin‐post interface]). However, the various treatments of the fiber post did not improve the PBS of the root dentin. HighlightsIt is crucial to maximize the bond strength between the root dentin and resin and between the resin and fiber post for the success of post‐core restorations.EDTA + laser‐activated irrigation significantly reduces debris or smear layers from the root dentin wall.The mechanical treatments on the fiber post surfaces cannot affect the push‐out bond strength (PBS); however, other additional parameters must be evaluated.Studies on the effects of different surface treatments on the fiber post and root dentin walls together with PBS could enrich the literature.

Which is the most effective disinfection method in primary root canals: Conventional or newly developed ones?

BACKGROUND The aim of the study was to evaluate the antimicrobial activity of the-potassium-titanyl-phosphate--the KTP laser and ozone in of primary root canals. MATERIALS AND METHODS Sixty primary incisor teeth were selected. The specimens were inoculated with 10 mL Enterococcus faecalis (E. faecalis). Groups: The KTP laser (1,5 W); gaseous ozone (150 s); sodium hypochlorite (NaOCl); saline group. Sterile paper points used to sample bacteria from the canals to tubes containing 5 mL of brain heart infusion broth. Then, 10 mL suspension was incubated in culture media for 24 h. Data were analyzed statistically using Kruskal-Wallis and Mann-Whitney U-test. RESULTS There were statistically significant differences between all groups (P<0.05). Complete sterilization was achieved in the 2.5% NaOCl group. The number of bacteria were significantly reduced in experimental groups in comparison to the saline group. CONCLUSION The KTP laser and ozone application provided a significant antibacterial effect in primary root canals; however, 2.5% NaOCl was superior.

Shaping ability of reciprocating single-file and full-sequence rotary instrumentation systems in simulated curved canals.

Objective: The purpose of this study was to evaluate the shaping ability of three nickel-titanium systems in simulated curved canals. Materials and Methods: Sixty simulated canals were prepared to apical size 25 with Reciproc, S5, and twisted file (TF) instruments. Standardized pre and postoperative images were taken using a digital camera, were superimposed and aberrations were recorded. Material removal was measured at five points: The canal orifice, halfway to the orifice, beginning of the curve, the apex of the curve, and end-point. The data were analyzed using Kolmogorov–Smirnov, analysis of variance, and Tukey tests. Results: The mean total width of the prepared canals in the Reciproc group was greater than the TF and S5 groups at halfway to the orifice, the beginning of the curve, the apex of the curve, and the end-point (P < 0.05). Mean absolute transportation was always <0.16 mm; however, significant differences occurred between the three systems at the orifice, halfway to the orifice, and the beginning of the curve (P < 0.05). TF created minimal absolute transportation at halfway to the orifice and the beginning of the curve, and greater absolute transportation at the orifice compared with the Reciproc and S5 instruments. However, the difference between the S5 and TF groups was not statistically significant at halfway to the orifice (P > 0.05). Conclusions: Under the conditions of the study, Reciproc produced widest canal shapes. TF provided more centered apical preparation and maintained the original canal shape well.