European Journal of Molecular & Clinical Medicine

Aim: The purpose of the research was to evaluate the fracture resistance of conventional full coverage crowns and two different designs of overlay restorations with margins located 2 and 4 mm above the gingival level.
Methodology: CAD/CAM lithium disilicate (IPS e.max CAD for CEREC/HT A1 C14, Ivoclar Vivadent) restorations (15 specimens/group) with 1.5 mm occlusal thickness and 1.0 mm chamfer were designed and fabricated with a chairside CAD/CAM system (CEREC, Dentsply Sirona). The restorations were prepared in three different designs: (1) full coverage crowns, (2) overlays with the margin located 2 mm above the gingiva, and (3) overlays with the margin located 4 mm above the gingiva. Restorations were cemented using conventional resin luting cement (Multilink, Ivoclar Vivadent) then finally loaded with a steel indenter until failure. Scanning electron microscopy observations of fractured surfaces were also conducted. Group results were analyzed with one-way analysis of variance, and the medians were evaluated independently with Kruskal-Wallis.
Results: The fracture force of CAD/CAM lithium disilicate restorations was significantly different (p < 0.001) depending on the design of the restoration. Full coverage crowns showed significantly higher force to fracture (1018.8 N) than both 
types of overlays (p = 0.002 for overlay 2.0 mm and p < 0.001 for overlay 4.0 mm above gingiva).
Conclusion: Full coverage chairside CAD/CAM lithium disilicate premolar crown showed higher fracture resistance than overlay restorations

Recent advances in ceramics have greatly improved the functional and esthetic properties of restorative materials.New materials offer an esthetic and functional oral rehabilitation, however their impact on opposing teeth is not well documented.The aim of the study was to evaluate prevalence of different materials for full veneer crowns used by dentists for a single full veneer crown based on location and choice made by dentist..A Cross-sectional, descriptive study was conducted in an institution, on randomly selected individuals. The study group consisted of adult patients who attended the outpatient Department of Prosthodontics from June 2019- March 2020.86000 case sheets were evaluated and frequency distribution test was used to explore the relationship between two variables.Comparison of the groups showed that Hand layered zirconia crown was preferred by 42.3 % individuals.Metal ceramic was predderd by 10.3% of the individuals.Monolithic zirconia was preferred by 47.4 % of the individuals.With the era of metal free crowns monolithic is preferred to solve the chipping problems which are to be considered before getting a hand layered zirconia crown or a metal ceramic crown.

Ceramics are broadly utilized as circuitous helpful materials in dentistry because of their extensive biocompatibility and satisfying aesthetics. The objective is to review the different CAD/CAM all-ceramic biomaterials. CAD/CAM all-ceramic biomaterials are highlighted and a subsequent literature search was conducted for the relevant subjects utilizing PubMed followed by manual search. Advancements in CAD/CAM innovation have catalyzed inquiry in all-ceramic biomaterials and their applications. Feldspathic glass ceramic and glass penetrated ceramic can be manufactured by conventional research facility strategies or CAD/CAM. The appearance of polycrystalline ceramics may be a coordinate result of CAD/CAM innovation without which the manufacture would not have been conceivable. The clinical employments of these ceramics have met with variable clinical victory. Numerous choices are presently accessible to the clinicians for the creation of aesthetic all ceramic restorations.