Mly divided into two groups (n = 10); Group CEREC (GC), which was produced by feldspathic ceramic and the Group Enamic (GE), which was produced by PICN. All teeth were endodontically treated and decoronated horizontally at 2 mm above the cemento-enamel junction. Endocrown preparations were done with 4 mm depth into the pulp chamber. Endocrowns were manufactured using CAD/CAM from ceramic blocks. Following adhesive cementation, all specimens were subjected to thermocycling. Marginal adaptation evaluated under SEM at 200 × magnification. Each specimen was fixed in a universal testing machine and a compressive load was applied at 45° to long axis of the teeth until failure. Failure load was recorded and failure modes were evaluated. Statistical analyses were performed with SPSS 19.0 software and data were compared using Mann-Whitney U test. Results: There were no significant differences in the marginal adaptation between two groups (P > 0.05). GE presented significantly higher fracture resistance when compared to GC (P < 0.05). Failure pattern was similar and characterized by the tooth-ceramic fracture on the force-applied side. Conclusions: CAD/CAM fabricated feldspathic ceramic and PICN endocrowns provide sufficient marginal adaptation, but the PICN endocrowns shows higher fracture resistance than the feldspathic ceramic endocrowns....

This study aimed to compare the effect of acid etching, sandblasting, or silica coating on the micro-shear bond strength of dual-cured resin cements to computer-aided design and computer-aided manufacturing (CAD/CAM) glass ceramic materials. Feldspathic, lithium disilicate, and zirconia-reinforced CAD/CAM ceramics were divided into four groups: control group (C), no surface treatment; hydrofluoric (HF) group, 5% HF acid-etched; sandblasting (SB) group, abraded with 50 µm aluminum oxide (Al₂O₃) particles; silica-coated (CJ) group, abraded with 30 µm silica-modified Al₂O₃ particles. Roughness values were obtained by using a profilometer. The cements were condensed on the surface-treated specimens and a micro-shear bond test was conducted. The ceramic material (p < 0.001) and surface treatment type (p < 0.001) significantly affected the micro-shear bond strength values. HF acid etching can be recommended for the surface pretreatment of feldspathic, lithium disilicate, and zirconia-reinforced CAD/CAM ceramics. Better bond strengths can be obtained with HF acid etching than with sandblasting and silica coating.

The color stability of dental ceramics in the oral cavity is influenced by multiple factors, including the patient’s dietary habits and oral hygiene practices, which can affect the optical and surface properties of resin-containing dental restorative materials. The purpose of this study was to evaluate the effects of surface finishing procedures and simulated tooth-brushing on the surface roughness, surface gloss, and color stability of resin matrix ceramics before and after coffee immersion. Forty specimens were prepared from a resin matrix ceramic and divided into four experimental groups according to surface finishing procedures, coffee immersion, and simulated tooth-brushing. The surface roughness, surface gloss, and color stability of the tested material were measured, and the data were statistically analyzed at a significance level of p < 0.05. The surface finishing procedures, measurement times, and application sequences affected surface roughness, surface gloss, and color stability. The most significant color differences occurred after coffee immersion; however, tooth-brushing had a more significant effect on the surface roughness and surface gloss. Coffee caused perceivable and clinically unacceptable color differences in the resin matrix ceramics. Tooth-brushing had a positive impact on the tested parameters. This study presents a novel approach by integrating both chemical (coffee immersion) and mechanical (tooth-brushing simulation) degradation processes to assess their combined and isolated effects on a resin matrix ceramic material. The findings provide clinically relevant insights into how finishing procedures and oral hygiene may influence the long-term esthetic performance of such restorative materials.

This study aims to compare the marginal and internal fit of lithium disilicate endocrowns produced by conventional and/or digital impression and fabrication techniques. Endocrown preparations were performed on 40 mandibular first molars. The teeth were divided into four groups (n = 10) based on the impression and fabrication technique; CON: conventional impression/manuel wax patterns/heat-pressed endocrowns, DCD: digital impression/CAD-CAM milled wax patterns/heat-pressed endocrowns, D3D: digital impression/3D printed resin patterns/heat-pressed endocrowns, DC: digital impression/digital design/CAD-CAM milled endocrowns. The marginal and internal fits of the endocrowns were measured by using the silicon replica technique and stereomicroscope with 57x magnification. The statistical analysis was carried out using the Kruskal-Wallis and paired two-sample t-tests. The significance level was set at p < 0.05. Marginal fit measurements revealed the following; CON: 111 μm, DCD: 96 μm, D3D: 91 μm, and DC: 93 μm. A statistically significant difference was found between the CON group and the other groups in the marginal fit measurement. Internal fit measurements revealed the following; CON: 120.75 μm, DCD: 112 μm, D3D: 114.88 μm, and DC: 122 μm. There was a statistically significant difference between the CON group and the DCD group in the internal fit measurement, while no significant difference observed between the other groups. It is concluded that all endocrowns had a clinically acceptable marginal and internal fit. The use of digitally generated patterns, CAD-CAM milled or 3D printed, in the fabrication of endocrowns can be effective in producing restorations with improved marginal and internal adaptation. The use of digital production methods can improve the marginal and internal adaptation of endocrown restorations.

Amaç: Korona Virus Hastalığı 2019 (COVID-19), Dünya Sağlık Örgütü (DSÖ) tarafından, tüm dünyadaki insanları etkileyen küresel bir halk sağlığı acil durumu olarak ilan edildi. Bu çalışmanın amacı, COVID-19 salgını sırasında diş hekimine başvuran hastaların COVID-19 hakkında bilgi ve endişelerini değerlendirmektir. Gereç ve Yöntemler: Temmuz-Ekim 2020 tarihleri arasında Zonguldak Bülent Ecevit Üniversitesi Diş Hekimliği fakültesine başvuran 400 hastaya, COVID-19 salgını ile ilgili anket yapıldı. Elde edilen verilerin istatistiksel anlamlılık farkını analiz etmek için ki-karetesti kullanıldı. P