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 ZrO2 after sandblasting and erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser application of different intensities.Material and Methods: Eighty pre-sintered ZrO2 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 Al2O3 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 Tukeyfs 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.Key words: Erbium, chromium: Yttrium, scandium, gallium, garnet laser, scanning electron microscopic, surface roughness, Y-TZP zirconi

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 μL 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 μL 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.Keywords: Antibacterial activity, KTP laser, ozone, primary root canal

Comparison of various current electronic apex locators to determine the working length using the clearing technique

Background: Correct working length determination is an important step for successful endodontic therapy. Objective: The objective was to compare in vitro the accuracy of three electronic apex locators (EALs) (DentaPort ZX [Morita Co., Tokyo, Japan], SIROEndo Pocket [Sirona Dental Systems, NY, USA], and Rootor [Meta Biomed, Cheongwon-gun, Korea]) in detecting the major foramen using the clearing technique. Materials and Methods: Forty-five human extracted single-rooted teeth with mature apices were used for the study and divided into three groups of 15 teeth each. All teeth were embedded in an alginate model, and the electronic measurements were taken following the manufacturers' orientations. Then, the teeth were cleared and photographed under a stereomicroscope with a digital camera. The distance from the file tip to the major foramen was measured using image analysis software program. Statistical analysis was performed using the Kruskal-Wallis, Mann-Whitney U, and Chi-square tests at a significance level of 0.05. Results: The mean distances from the file tip to the major foramen were 0.164 ± 0.292, -0.162 ± 0.234, 0.341 ± 0.166 mm in the DentaPort ZX, SIROEndo Pocket, and Rootor groups, respectively. Statistical analysis showed that there was a significant difference between SIROEndo Pocket and Rootor (P 0.05). Conclusion: DentaPort ZX located the major foramen with 100% accuracy within the range of ± 0.5 mm. However, the accuracy of the SIROEndo Pocket and Rootor in locating the major foramen within ± 0.5 mm was 73.3% and 86.7%, respectively. All EALs showed an acceptable determination of the major foramen within the range of ± 0.5 mm

Comparison of various current electronic apex locators to determine the working length using the clearing technique

Background: Correct working length determination is an important step for successful endodontic therapy.Objective: The objective was to compare in vitro the accuracy of three electronic apex locators (EALs) (DentaPort ZX [Morita Co., Tokyo, Japan], SIROEndo Pocket [Sirona Dental Systems, NY, USA], and Rootor [Meta Biomed, Cheongwon-gun, Korea]) in detecting the major foramen using the clearing technique.Materials and Methods: Forty‑five human extracted single‑rooted teeth with mature apices were used for the study and divided into three groups of 15 teeth each. All teeth were embedded in an alginate model, and the electronic measurements were taken following the manufacturers’ orientations. Then, the teeth were cleared and photographed under a stereomicroscope with a digital camera. The distance from the file tip to the major foramen was measured using image analysis software program. Statistical analysis was performed using the Kruskal–Wallis, Mann–Whitney U, and Chi‑square tests at a significance level of 0.05.Results: The mean distances from the file tip to the major foramen were 0.164 ± 0.292, −0.162 ± 0.234, 0.341 ± 0.166 mm in the DentaPort ZX, SIROEndo Pocket, and Rootor groups, respectively. Statistical analysis showed that there was a significant difference between SIROEndo Pocket and Rootor (P < 0.05). However, no significant difference was found between DentaPort ZX and other EALs (P > 0.05).Conclusion: DentaPort ZX located the major foramen with 100% accuracy within the range of ± 0.5 mm. However, the accuracy of the SIROEndo Pocket and Rootor in locating the major foramen within ± 0.5 mm was 73.3% and 86.7%, respectively. All EALs showed an acceptable determination of the major foramen within the range of ± 0.5 mm.Key words: Clearing technique, electronic apex locator, endodontics, major forame

Effect of Needle Insertion Depth and Apical Diameter on Irrigant Extrusion in Simulated Immature Permanent Teeth

The aim of this study was to compare the amount of irrigant extrusion in simulated immature permanent teeth when the apical diameter and needle insertion depth were varied. Thirty single-rooted maxillary incisors with straight root canals were selected. The root length was standardized to a length of 9 mm. The teeth were divided into two experimental groups according to the degree of apical enlargement (n = 15). The apices were enlarged to a diameter of 1.10 mm or 1.70 mm by using a #3 or #6 peeso reamer, respectively, to simulate immature teeth. The irrigation solution was applied 2 or 4 mm short of the working length (WL) in each experimental group. The glass vial model was used for the collection of extruded irrigant beyond the root apex. A two-way repeated measures analysis of variance test showed that there was no significant difference between different needle insertion depths (2 and 4 mm short of the WL) in the group with an apical diameter of 1.70 mm (p > 0.05). In the group with an apical diameter of 1.10 mm, a 32% increase in irrigant extrusion was observed when the needle was positioned at 2 mm (p < 0.05). Regarding the effect of apical diameter, the group with a diameter of 1.70 mm showed more apical extrusion of the irrigant (34% increase for the needle positioned at 2 mm and 68% increase for the needle positioned at 4 mm). It was observed that the needle insertion depth and apical diameter have a significant effect on irrigant extrusion in immature permanent teeth.Wo