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  • [ X ]
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    Evaluation of fracture resistance and crack propensity of bulk-fill composite restorations reinforced by polyethylene fiber
    (Bmc, 2025) Senol, Ayse Asli; Manav, Aybike; Dogu Kaya, Bengu; Yilmaz Atali, Pinar; Kahramanoglu, Erkut; Tarcin, Bilge; Turkmen, Cafer
    Background In clinical restorative applications, different materials and techniques are used to replace lost tooth tissue and compensate for the fracture resistance that are essential for function. Further investigation is required to ascertain the effect of polyethylene fiber application, which is one of these interventions, on the fracture resistance, fracture location, reparability and crack propagation of premolar teeth restored with direct composite resin restorations. This in-vitro study aimed to evaluate fracture resistance and crack propagation of two bulk-fill composites (BRC) with/without polyethylene-fiber in extensive Class I resin composite restorations. Methods Cavities were prepared on 40 mandibular premolars. In half of the samples (n = 20), polyethylene-fiber (Ribbond Fiber/RF) coated with adhesive resin was placed on cavity floor. Half of the teeth were restored with SonicFill 3 and the other half with Charisma Bulk Flow ONE.The groups were as follows: SonicFill 3 + Fiber(SF + RF), SonicFill 3(SF), Charisma Bulk Flow ONE + Fiber(CO + RF), and Charisma Bulk Flow ONE(CO). Following 20,000 thermo-cycles fracture resistance (FR) was determined. Crack number/orientation were assessed with transillumination using two different wavelengths, before (t(0)) and after preparation (t(p)), and following fracture test (t(f)).Visual examination was performed with micro-CTto evaluate the adaptation. Data were analyzed using Independent samplesT-test, Fisher's Exact, Fisher Freeman Halton, Pearson Chi-Square and Cochran's QTests (P < .05). Results No statistically significant difference was found between the FR of groups (P = .994) with and without RF (P = .167) according to BRC. The mean FR values in decreasing order were CO (761.09 +/- 224.32) > SF + RF (671.08 +/- 150.51) > CO + RF (669.95 +/- 358.44) > SF (580.7 +/- 269.04). A reduction in the formation of irreparable fracture patterns was detected in RF groups. Crack number/orientation did not differ according to BRC and RF application. Statistically significant increase was observed in crack formation over examination periods (t(f)> t(p)> t(0); P < .001). Conclusions The reinforcement of large cavities with polyethylene fibers changed the fracture pattern of the restorations towards repairable, whereas had no effect on fracture resistance and crack formation. Furthermore, the placement of polyethylene fibers may have an adverse effect on the adaptation of the cavity. In clinical applications, both wavelengths can be used for transillumination testing in crack inspection.
  • [ X ]
    Öğe
    The effect of cavity depth on accuracy of intraoral scanners in intra-coronal restorations
    (Bmc, 2025) Ozden, Yunus Emre; Kaya, Bengu Dogu; Akbal, Cagla; Yilmaz Atali, Pinar; Ozkurt-Kayahan, Zeynep
    Purpose This study aimed to evaluate the effect of cavity depth on the accuracy of intraoral scanners (IOS) in intra-coronal restorations, focusing on trueness and precision as defined by International Organization for Standardization (ISO) 5725 standards. Materials and methods Three intra-coronal cavity designs with depths of 2.5 mm (n = 10), 5 mm (n = 10), and 7.5 mm (n = 10) were fabricated using 3-Dimentional (3D) printed tooth models. Scans (n = 30) were performed using the Trios 3 intraoral scanner, and accuracy was assessed by comparing scanned models to reference models. Trueness was measured as the root mean square (RMS) deviation, and precision was calculated from the interquartile range of average absolute distances. Statistical analyses were conducted using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni correction. Results The accuracy of the IOS was significantly lower at a cavity depth of 7.5 mm compared to 5 mm and 2.5 mm (p < 0.05). RMS values were highest for the 7.5 mm depth, while the lowest precision was observed at this depth. Conclusion Cavity depth significantly affects the accuracy of IOS in intra-coronal restorations, with deeper cavities resulting in reduced accuracy. This highlights the importance of considering cavity depth when planning IOS workflows. This study shows that scanning accuracy decreases when the distance between the cavity floor and the cusp tip exceeds 5 mm. Elevating the cavity floor with direct methods may help improve scanning accuracy and enhance restoration outcomes.