Comparative radiopacity of conventional and full-contour Y-TZP ceramics.

The purpose of this study was to evaluate the radiopacity of different yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramics used in the fabrication of fixed dental prostheses. Disk-shaped specimens (N=120, n=30 per group) were fabricated with thicknesses of 0.3, 0.5, and 1 mm from the following four Y-TZP ceramics: Cercon ht (Degudent) (CZ), Prettau (Zirkonzahn) (ZZ), Alliance (Kuraray Noritake Dental) (NA), and Ice Zirkon (Zirkonzahn) (ICE). The optical densities of each material were measured from radiographic images, and each material (N=1) were characterized by using XRD and SEM. The results were analyzed with oneway analysis of variance and the Tukey-Kramer test (α=0.05). In the case of the ICE and NA specimens, the radiopacity significantly differed with thickness (p<0.05). However, the radiopacities of 0.5- and 0.3-mm-thick CZ and ZZ specimens were not significantly different (p>0.05). Full-contour Y-TZP materials have higher radiopacities than those of the conventional Y-TZP materials in decreased thicknesses.

Periapical status and quality of root fillings and coronal restorations in an adult Turkish subpopulation.

OBJECTIVES: To investigate the quality of root fillings and coronal restorations and their association with periapical status in an adult Turkish subpopulation. METHODS: A total of 400 subjects were examined. Panoramic radiographs of all participants and additional periapical radiographs of affected teeth were processed. The frequency of root canal treatment and the periapical status of all root filled teeth were evaluated. The relationship between the radiographic quality of root fillings and coronal restorations was examined by chi-squared statistical analysis. RESULTS: A total of 9460 teeth were examined. The total number of root filled teeth was 890 (9.39%), and 658 (73.9%) had apical periodontitis (AP). There was a significant correlation between the presence of periapical pathology and inadequate root canal fillings (P<.05). Presence of AP in root filled teeth was associated with inadequate adaptation of the filling (OR=1.097; P=0.54), and with poor radiographic quality of the coronal restoration (OR=0.91; P=0.70), and with poor radiographic quality of the filling restoration (OR=0.97; P=0.92). Only 24.5% of the root fillings were adequate. The highest percentage of root fillings was found in maxillary right first molars (6.9%). CONCLUSIONS: The results demonstrate a low prevalence of root-filled teeth and poor quality of coronal restorations and root fillings consistent with a high prevalence of apical periodontitis in a Turkish subpopulation.

Comparision of biocompatibility and cytotoxicity of two new root canal sealers.

The aim of this study was to investigate the remote organ toxicity and connective tissue reaction of two new root canal sealers ("GuttaFlow(®)" and "EndoREZ(®)") and to compare them with zinc oxide eugenol sealer using biochemical and histopathological parameters. A total of 60 white albino Wistar rats were used in the study. 0.1ml of GuttaFlow(®), EndoREZ(®) or Kerr Pulp Canal Sealer(®) were administered subcutaneously into the mid-dorsal thoracic region of rats (15 in each group). Control rats were given saline only. Rats were decapitated after 24h, on day 7 and on day 30 of the experiment and tissue samples from lung, liver, kidney and skin were removed for the determination of malondialdehyde (MDA) and glutathione (GSH) levels. In parallel, tissues were also examined histologically. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels, and creatinine and blood urea nitrogen (BUN), concentrations (BUN) were measured to assess liver and kidney functions, respectively. Tumor necrosis factor (TNF) and lactate dehydrogenase (LDH) were also assayed in serum samples. No statistical differences were found among the control and EndoREZ(®), GuttaFlow(®) and Kerr Pulp Canal sealers regarding tissue MDA, GSH levels or serum parameters (p>0.05) at all time points examined. Both of the new root canal sealers showed good compatibility and acceptable tissue toxicity.

Comparison of the different techniques to remove fractured endodontic instruments from root canal systems.

OBJECTIVES: To evaluate the success of certain methods that can be used in the removal of separated instruments from different levels in curved and straight canals. METHODS: Instrument removal attempts were undertaken on 63 straight and 30 curved canals containing a pre-fractured instrument using the ultrasonics under the visualization of an operating microscope or conventional methods. In straight canals, a Masseran Kit was additionally used to these techniques. The success of instrument removal in relation to the techniques used and the location of the fragments in the root canal were evaluated. Successful treatment was defined by the removal or complete by passing of the fragments. RESULTS: The overall success rate was found 93.3% with ultrasonics and 66.6% when only conventional methods were used in curved canals. In straight canals, also the success rate was the highest with ultrasonics (95.2%). This was followed by conventional method (80.9%) and the least by Masserann Kit (47.6%). When the success rate was investigated according to the location of the broken instruments, the lowest rate was found in the apical third of root canal. CONCLUSIONS: Location of the fragment and the shape of the root canal influence the success of fractured instrument management. Ultrasonics under the visualization of an operating microscope was found to be an effective removal method.

Apical leakage of different gutta-percha techniques: thermafil, js quick-fill, soft core, microseal, system B and lateral condensation with a computerized fluid filtration meter.

OBJECTIVES: To investigate apical leakage of roots filled with 6 different gutta-percha techniques; Thermafil, JS Quick-Fill, Soft Core, Microseal, System B and lateral condensation using a new computerized filtration meter. MATERIALS AND METHODS: 60 extracted single rooted teeth were used. Coronal part of each tooth was removed and the root canals were prepared with step-back technique. The roots were randomly divided into six groups of 10 teeth, filled by one of the obturation technique and Kerr sealer. The teeth were kept in 100% humidity for 2 years. After this period, apical parts of roots (10 +/- 0.05 mm) were attached to computerized fluid filtration meter. Apical leakage quantity was determined as mul.cmH(2)O(-1).min(-1). RESULTS: Statistical analysis indicated that Thermafil, Soft Core, Quick-Fill and System B techniques showed lower leakage than Microseal and lateral condensation (P < .05). However, statistically no difference was found among the core techniques and no difference was found between microseal and lateral condensation techniques (P > .05). CONCLUSIONS: Thermafil, Soft Core, Quick-Fill and System B techniques showed lower leakage than Microseal and lateral condensation. In addition, this new computerized fluid filtration meter allowed quantitative measurement of leakage easily.