Three-dimensional evaluation of the machinability of monolithic CAD/CAM-generated posterior crowns by nano-hybrid ceramic / 대한치과재료학회지

The purpose of this study comparatively analyzed the machinability of various dental hybrid blocks manufactured by using the CAD/CAM system. Three hybrid composite blocks (Vita enamic, Lava Ultimate, GC Cerasmart) were used for experimental groups and one conventional ceramic block (Vita Mark II) was used for control. The digital impression of the master model and abutment was taken by using a scanner, and then the CAD software program was used to design restorations. The four-axis milling machine (inLab MCXL; Sirona Dental Systems GmbH, Bensheim, Germany) was used four materials. The digitized data was superimposed with 3D inspection software to quantitatively obtain the machinability of a ceramic crown, and visual differences were confirmed with a color map. The root mean square (RMS) values of ceramic crown group were statistically analyzed with one-way ANOVA (α=0.05). While there was a significant difference in the machinability of the internal surface, among four groups, there was statistically significant difference between conventional (VM group) and hybrid ceramic (VE, LU, GC groups) (p<0.05). Consequently, the machinability of VM is lower than that of other hybrid ceramics, and the machinability of VE is better than that of LU and GC. For ceramics as final restorations, manufacturing of dental restorations using hybrid composite ceramic is recommended.

Clinical effect of resin hybrid ceramic onlay in repairing posterior tooth defects / 口腔疾病防治

Objective@#To investigate the clinical effect of restoration of posterior teeth with machinable CAD/CAM resin hybrid ceramic (VITA Enamic) onlays after root canal treatment. @* Methods @#136 posterior teeth restored after root canal treatment in our hospital were selected as the research subjects. The posterior teeth were restored chairside with CAD / CAM ceramic onlays to recover occlusion relation and protect residual dental tissues. With 68 teeth in each group, one group was restored with a machinable CAD / CAM resin hybrid ceramic (VITA Enamic) while the control group received zirconia-reinforced lithium silicate ceramic (VITA Suprinity). Before bonding, all the onlays were examined for good adjacency, fitness and occlusion, and then the adhesive surface was etched with hydrofluoric acids. After isolating the rubber dams in the mouths, the onlays were bonded with dual-cure resin cements. The patients were followed up for 24 months to compare the degree of prosthesis integrity, marginal fitness, gingival health, dental integrity, color matching and secondary caries. @* Results @#After restoration, all the onlays were in harmony with the surrounding teeth with good aesthetic effect and suitable marginal fit. Two years later, there were no significant differences in the marginal fitness, gingival health, dental integrity or secondary cavities between the two groups (P > 0.05). In terms of restoration integrity, the VITA Enamic onlays (100%) were intact and displayed good retention. The group that received VITA Suprinity had 6 onlay (9.23%) fractures and a success rate of 90.77%; however, the residual dental tissues did not break. The difference of prosthesis integrity between the two groups was statistically significant (χ2= 4.45, P < 0.05). @*Conclusion@#Chairside CAD/CAM resin hybrid ceramic (VITA Enamic) onlays can quickly restore posterior teeth after root canal therapy and better protect the residual dental tissue.

The effect of light sources and CAD/CAM monolithic blocks on degree of conversion of cement

PURPOSE: To assess the degree of conversion (DC) and light irradiance delivered to light-cured and dual-cured cements by application of different light sources through various types of monolithic computer-aided design and computer-aided manufacturing (CAD/CAM) materials. MATERIALS AND METHODS: RelyX Ultimate Clicker light-cured and dual-cured resin cement specimens with 1.5-mm thicknesses (n=300, 10/group), were placed under four types of crystalline core structure (Vita Enamic, Vita Suprinity, GC Ceresmart, Degudent Prettau Anterior). The specimens were irradiated for 40 seconds with an LED Soft-Start or pulse-delay unit or 20 seconds with a QTH unit. DC ratios were determined by using Fourier transform infrared spectroscopy (FTIR) after curing the specimen at 1 day and 1 month. The data were analyzed using the Mann-Whitney U test (for paired comparison) and the Kruskal-Wallis H test (for multiple comparison), with a significance level of P < .05. RESULTS: DC values were the highest for RelyX Ultimate Clicker light-cure specimens polymerized with the LED Soft-Start unit. The combination of the Vita Suprinity disc and RelyX Ultimate Clicker dual-cure resin cement yielded significantly higher values at both timepoints with all light units (all, P < .05). CONCLUSION: Within the limitations of this study, we conclude that the DC of RelyX Ultimate Clicker dual-cure resin cement was improved significantly by the use of Vita Suprinity and the LED Soft-Start light unit. We strongly recommend the combined use of an LED light unit and dual-cure luting cement for monolithic ceramic restorations.

Effects of staining liquids and finishing methods on translucency of a hybrid ceramic material having two different translucency levels

PURPOSE: Beverages may affect the translucency of esthetic dental restorative materials. The aim of the present study was to investigate the effects of coffee and red wine on the translucency of a PICN material with two translucency levels, and finished with different methods. MATERIALS AND METHODS: 2M2 high translucent and translucent VITA Enamic hybrid ceramic blocks were investigated. Rectangular specimens with the dimensions of 12 mm × 14 mm × 2 mm were prepared. The specimens were finished and polished with different methods as suggested by the manufacturer. The translucency parameters of the specimens were evaluated before and after 24 hours, 7 days, and 28 days immersion in distilled water, coffee and red wine. Translucency parameters were measured using a portable spectrophotometer. RESULTS: At the end of 28 days, there was no statistically significant difference between the groups of specimens kept in coffee (P>.05). In the red wine groups, there was a statistically significant difference between the control group and all other groups (P<.05) at the end of 28 days. CONCLUSION: The translucency of hybrid ceramic for a restoration may not be important regarding the effects of coffee on translucency change because the specimens with different translucencies and finishing methods that were immersed to coffee had similar translucency parameters at the end of 28 days. The translucency of hybrid ceramic may be important in the case of red wine, however, since the results showed that highly translucent specimens exposed to red wine demonstrated better translucency parameters than specimens made from translucent blocks at the end of 28 days.

Restorative management using hybrid ceramic of a patient with severe tooth erosion from swimming: a clinical report

This clinical report presents the clinical appearance and treatment approach in a case of excessive anterior teeth erosion resulted from swimming in a poorly-chlorinated swimming pool. Clinical findings revealed tooth sensitivity, severe enamel erosion resembling veneer preparations, and the presence of anterior open bite. A novel hybrid ceramic (Vita Enamic) was chosen for fabricating full-coverage crowns for this patient. After 6-months follow-up, the tooth sensitivity disappeared and the patient was satisfied with esthetic outcome. The hybrid ceramic restorations can be recommended with no complications.