ABSTRACT
The aim of this systematic review was to provide an overview of the technical and clinical outcomes of conventional, speed sintering and high-speed sintering protocols of zirconia in the dental field. Data on precision, mechanical and optical parameters were evaluated and related to the clinical performance of zirconia ceramic. The PICOS search strategy was applied using MEDLINE to search for in vitro and in vivo studies using MeSH Terms by two reviewers. Of 66 potentially relevant studies, 5 full text articles were selected and 10 were further retrieved through a manual search. All 15 studies included in the systematic review were in vitro studies. Mechanical, precision and optical properties (marginal and internal fit, fracture strength and modulus, wear, translucency and opalescence, aging resistance/hydrothermal aging) were evaluated regarding 3-, 4- and 5-YTZP zirconia material and conventional, high- and high-speed sintering protocols. Mechanical and precision results were similar or better when speed or high-speed sintering methods were used for 3-, 4- and 5-YTZP zirconia. Translucency is usually reduced when 3 Y-TZP is used with speed sintering methods. All types of zirconia using the sintering procedures performed mechanically better compared to lithium disilicate glass ceramics but glass ceramics showed better results regarding translucency.
ABSTRACT
This study assessed the bond strength of prefabricated post systems at different root levels of endodontically treated teeth. One-rooted human premolars (N = 70; n = 10) were cut to 2 mm above the cement-enamel junction. Root canals were treated and randomly assigned to one of the seven post systems: T: Titanium (Mooser), ZrO: Zirconia (Cosmopost), G: Fiber (FRC Postec Plus), E1: Fiber (Direct) (Everstick post), E2: Fiber (Indirect) (Everstick post), PP: Fiber (PinPost), and LP: Injectable Resin/Fiber composite (EverX Posterior). All posts were luted using a resin cement (Variolink II), and the roots were sectioned at the coronal, middle, and apical root levels. Push-out tests were performed in the Universal Testing Machine (0.5 mm/min). Data (MPa) were analyzed using two-way ANOVA and Tukey's tests (α = 0.05). The results showed that the bond strength (mean ± SD) of E2 posts were highest (5.3 ± 2.7) followed by PP (4.1 ± 2.0); G (4.0 ± 1.6); LP (2.6 ± 1.9): T (2.2 ± 1.5) and ZrO (1.9 ± 1.0) posts systems. No significant differences were found in bond strength of all post systems. The bond strength in the coronal root level was the highest with 3.6 ± 2.2 MPa. The bond strength of FRC post systems was significantly higher than those of rigid posts of titanium or ZrO2. Bond strength results were the highest in the coronal root level for all tested post systems but did not differ significantly from the other two root levels.
ABSTRACT
OBJECTIVE: The aim of this study was to determine the frequency of endodontic treatment in an adult Ukrainian population in relation to the age and its distribution depending on the type of the teeth. PATIENTS AND METHODS: Materials and methods: A total of 435 digital panoramic radiographs of adults (aged 18 to 72 years) were examined. A tooth was qualified as root filled (endodontically treated), if radiopaque root-filling material was determined in the pulp chamber and/or in the root canals. Pearson's chi-squared test (χ2) and Spearman's rank correlation were applied for data analysis. RESULTS: Results: It was revealed that 82.5% of patients had previously received endodontic treatment of the teeth. The overall percentage of root filled teeth in adult dentition is 12.08%. The analysis of the rate of endodontically treated teeth in different age groups identified an increasing of treated teeth with age - from 5.2% in the youngest cohort (18-19 years old) to 24.9% in the oldest cohorts. It was revealed that 822 teeth (14.2%) on maxilla and 569 (9.9%) on the mandible were endodontically treated. Most often root filled teeth were first mandibular molars (39.3%), first maxillary molars (26.7%) and second maxillary premolars (20.4%). Much lower rate of endodontic treatment were considered in lower mandibular incisors and canines (0.7%, 0.9% and 1.5% respectively). CONCLUSION: Conclusions: A total of 82.5% examined adults had one or more endodontically treated teeth in this study. The obtained results prove the necessity of prevention of carieswith special emphasis on the first maxillary and mandibular molars, and maxillary second premolars, which have significantly higher frequency of root canal treatment in comparison to other teeth groups.
