Aim: Evaluation of marginal gaps and fracture strength of two sets of CAD/CAM anterior endocrown ceramic materials (CERASMART & CEREC Tessera)

Materials and Methods: Thirty two anterior endocrowns were constructed. The samples were allocated into two groups based on type of ceramic materials (n=16). Group1 was Tessera ceramic material, while group 2 was CERASMART ceramic material. Each group was split into two sub-groups (n=8) based on the test they were subject to; Sub-group A for marginal gap test and sub-group B for fracture resistance test. Marginal gap was initially measured before cementation and thermocycling using an optical digital stereomicroscope then re-evaluated after cementation and thermocycling. All samples were cemented by self-adhesive resin cement (Biscem). Then samples included a fracture resistance test with a universal testing machine.

Results: There was significant increase in total marginal gaps before and after cementation and thermocycling in both groups: (60.9±9.5 μm - 70.4±8.7 μm) in CERASMART group and (62.3±8.7 μm - 70.1±8.3 μm) in Tessera group. There was insignificant difference in fracture resistance between both groups and the value with greatest mean fracture resistance was observed for CERASMART group (739.2±140.2N) compared to Tessera group (623.6±114.6N). The failure modes of CERASMART showed more damage to the tooth substructure in comparison to CEREC Tessera.

Conclusion: Both CEREC Tessera and CERASMART endocrowns materials exhibited a clinically acceptable range for the marginal gap values. CERASMART endocrowns provided promising fracture resistance values as well as CEREC Tessera endocrowns as a mode of treatment of endodontically treating maxillary anterior teeth.