PubMed İndeksli Açık & Kapalı Erişimli Yayınlar
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Item Marginal fit of 3-unit CAD-CAM zirconia frameworks fabricated using cone beam computed tomography scans: an experimental study(2021) Belgin, Huseyin Berkay; Kale, Ediz; Ozcelik, Tuncer Burak; Yilmaz, Burak; 34665345Whether cone beam computed tomography (CBCT) scans can be used for the fabrication of computer-aided design and computer-aided manufacturing (CAD-CAM) fixed dental prostheses (FDPs) is not known. The purpose of the present study was to compare the marginal fit of 3-unit zirconia FDPs fabricated by using CBCT or 3-dimensional (3D) laboratory scanning. Extracted second premolar and molar teeth in a maxillary typodont model were prepared. The first molar was removed and the typodont model was scanned with a laboratory or a CBCT scanner to generate two virtual 3D cast groups (3DL and CBCT). Forty four 3-unit zirconia FDPs were designed on virtual casts and milled. The vertical marginal discrepancy (VMD) was measured by x100-magnification microscopy at seven locations on each abutment. A total of 616 measurements were made at 14 fixed locations in two groups of 22 specimens. The VMD data for 3DL and CBCT groups were statistically analyzed using the Mann-Whitney U test (alpha = 0.05). The mean VMDs on premolar ranged between 44 and 55 mu m (median: 43-55 mu m) in 3DL, and 74 and 100 mu m (median: 72-93 mu m) in CBCT; and on the molar, between 47 and 114 mu m (median: 46-114 mu m) in 3DL, and 91 and 162 mu m (median: 93-156 mu m) in CBCT. There was a significant difference between the gaps in 3DL and CBCT groups (p < 0.001). FDPs fabricated using 3D laboratory scanner had significantly smaller VMDs. Nevertheless, the 3-unit zirconia FDPs fabricated using CBCT scans presented promising marginal integrity.Item Comparative evaluation of periodontal effects and survival rates of Memotain and five-stranded bonded retainers A prospective short-term study(2020) Kartal, Yasemin; Kaya, Burcak; Polat-Ozsoy, Omur; 32780168Purpose To prospectively compare the short-term periodontal effects and survival rates of mandibular lingual canine-to-canine Memotain (CA-Digital, Mettmann, Germany) and five-stranded bonded retainers. Methods In all, 52 patients requiring retention after orthodontic treatment were assigned to 2 study groups (n = 26 in each group). Retention was provided by Memotain retainers which were fabricated digitally using CAD-CAM (computer-aided design and computer-aided manufacturing) technology in the first group and by five-stranded retainers which were fabricated manually using a conventional bending method in the second group. The patients were examined at the following time points: 1 week, 1 month, 3 months and 6 months. Plaque index, gingival index, probing depth, marginal recession, bleeding on probing, failure rate per tooth, and survival rate of retainer wires were analyzed by Mann-Whitney U, Friedman, Wilcoxon signed-rank, and chi(2) tests. Results The differences between the groups were nonsignificant for plaque index, gingival index, probing depth, marginal recession, bleeding on probing, failure rate per tooth and survival rate of retainer wires. Significant differences were observed within the groups throughout the follow-up period for plaque index and probing depth. The survival rates of retainer wires were 77% for the Memotain retainers and 73% for the five-stranded retainers for the 6-month follow-up period. Conclusions Periodontal outcomes and survival rates of Memotain and five-stranded mandibular lingual bonded retainers were similar. Furthermore, periodontal health was maintained and considerably high survival rates were achieved with both retainer types.