All-ceramic restorations on posterior dental implants - A Systematic Review

Objectives: The aim of this systematic review was to evaluate the survival and success rate of all-ceramic/porcelain crowns on posterior dental implants.
Methods: Five electronic databases were searched up to September 2015 without limitations. The terms “crown,” “all-ceramic,” "implant," “porcelain”, and “posterior” were used.
Titles and abstracts were assessed and those that fulfilled the inclusion criteria were selected for assessment of the full text. In vivo and in vitro studies were included. Studies that only evaluated abutment survival or success rate were not included
Results: 688 articles were retrieved among the five databases as potentially eligible. Titles and abstracts that fulfilled the inclusion criteria (145) were selected for further analysis. 67 studies were selected and after removing duplicates 34 were analyzed. 14 studies met the inclusion criteria (8 in-vivo, 6 in-vitro).
Conclusions: There was a general consensus that after performing several fracture load stress tests on zirconia ceramic crowns, they have sufficient strength to allow clinical testing of these crowns as a competent alternative to metal ceramic crowns (fracture load exceeding 4.7kN). Studies found that the survival rates of ceramic-crowns (yttrium-stabilized zirconia polycrystals) are slightly lower but comparable to that of metal ceramic crowns (>93%). According to several studies the survival rate for implant supported crowns is slightly higher than tooth supported crowns, however the majority of the studies reported veneer fracture as the most common reason for crown failure and a higher occurrence of porcelain chipping. Clinical significance: recent studies suggest that implant supported all-ceramic crowns are a suitable alternative for the increasing demand in aesthetic restorations in the posterior regions of the mouth.