Comparison of implant versus tooth-supported zirconia-based single crowns in a split-mouth design: A 4-year clinical follow-up study

WOS: 000388957000017PubMed ID: 26924133This study aims to evaluate the 4-year clinical performance of tooth versus implant-supported single-unit zirconia crowns (LAVA (TM)) placed on posterior region. Twenty-four patients (10 men and 14 women) who had received 48 single crowns (24 implant-supported and 24 tooth-supported) from January 2007 to December 2009, were included. California Dental Association (CDA) quality assessment system, plaque and gingival index scores were used to evaluate the performance of the crowns at baseline and at all follow-up examinations. During the follow-up period, no fracture of zirconia coping has occurred. Major complication was chipping in three patients that required a new crown fabrication. Except for the failure ones, all crowns in both groups were rated as satisfactory at the follow-up examinations based on the CDA quality assessment criteria. There were no statistically significant differences between tooth and implant-supported crowns in terms of periodontal parameters. The present 4-year follow-up clinical study demonstrates that single-unit tooth- and implant-supported zirconia crowns have similar prosthetic and periodontal outcomes. Single-unit implant or tooth-supported zirconia crowns may be considered acceptable treatment modalities for restoration of either missing or compromised posterior teeth

Effects of topically applied contractubex® on epidural fibrosis and axonal regeneration in injured rat sciatic nerve

AIM: To investigate the effects of Contractubex (R) (Cx) on peripheral nerve regeneration and scar formation. MATERIAL and METHODS: A surgical procedure involving sciatic nerve incision in 24 adult male Sprague-Dawley rats followed by epineural suturing was performed. In weeks 4 and 12 following surgery, macroscopic, histological, functional, and electromyographic examinations of the sciatic nerve were conducted. RESULTS: No significant difference was found between the Cx group and the control group in terms of sciatic function index (SFI) and distal latency results at week 4 (p>0.05). However, significant improvements in the Cx group were observed in SFI amplitudes and nerve action potentials at week 12 (p<0.001 and p<0.001, respectively). Significant improvements were found in the amplitudes of nerve action potentials in the treatment group after weeks 4 and 12 (p<0.05 and p<0.001, respectively). Macroscopically and histopathologically, epidural fibrosis decreased (p<0.05 and p<0.001, respectively). For both measurement times, the treatment group had significantly higher numbers of axons (week 4, p<0.05; week 12, p<0.001), and the treatment group had better results regarding its axon area (weeks 4 and 12, p<0.001) and myelin thickness (weeks 4 and 12, p<0.05). CONCLUSION: Cx, which is applied topically in peripheral nerve injury, affects axonal regeneration and axonal maturation positively and reduces the functional loss

EĞİTSEL OYUNLAR

Eğitim, bireyin öğrenim hayatını, toplum içindeki statüsü ve sosyal yaşantısını etkileyen ve belirleyen bir süreçtir. Eğitim uzun bir süreçtir ve bu süreçten verim alınmak isteniyorsa zamanı iyi değerlendirmek gerekir. (Yaşartürk ve Bilgin, 2018) (Volkan Koç 2020)

Nanoscale charging hysteresis measurement by multifrequency electrostatic force spectroscopy

We report a scanning probe technique that can be used to measure charging of localized states on conducting or partially insulating substrates at room temperature under ambient conditions. Electrostatic interactions in the presence of a charged particle between the tip and the sample is monitored by the second order flexural mode, while the fundamental mode is used for stabilizing the tip-sample separation. Cycling the bias voltage between two limits, it is possible to observe hysteresis of the second order mode amplitude due to charging. Results are presented on silicon nitride films containing silicon nanocrystals. (c) 2008 American Institute of Physics

Effect of anti-rotational abutment features and novel computerized fabrication techniques on the marginal fit of implant-supported metal copings

Purpose An in vitro study to compare the marginal fit of cobalt-chromium (Co-Cr) metal copings fabricated with selective laser melting (SLM), computer-aided design and computer-aided manufacturing (CAD/CAM) milling, and lost-wax (LW) techniques, on abutments with two different antirotational features. Materials and Methods A total of 60 stainless steel abutments with the same length and convergence angles were fabricated using a numerical control machining. Half of the abutments had one flat plane, while the other half had three grooves as an antirotation feature. Thirty abutments of each kind were then divided into three subgroups, and metal copings were fabricated with SLM, CAD/CAM milling, or the LW technique (n = 10). The metal copings were cemented with polycarboxylate cement. Marginal gap measurements were performed using a stereomicroscope at a magnification of x 45 and data were analyzed with two-way analysis of variance (ANOVA) tests. Results The LW (p= 0.002) and CAD/CAM (p< 0.001) techniques exhibited increased marginal gaps on the abutments with a three groove antirotational feature; however, no significant difference was detected with the SLM technique (p= 0.259). The copings fabricated with the SLM technique demonstrated significantly lower gap values in both abutment types (p< 0.001). Conclusion While all marginal gap values were within the clinically acceptable range (<120 mu m), abutments with more antirotational grooves exhibited wider marginal gaps with the LW and CAD/CAM techniques