Statement of problem: Longer-term clinical trials with success data are required to validate the current design options of Ti base as viable abutments.
Objective: The aim of this clinical research was to investigate the influence of abutment designs on the clinical outcome of screw- and cement-retained, implant-supported monolithic zirconia crowns.
Material and methods: A total of 28 patients with missing 30 single maxillary premolar areas were implanted (4.1x12mm), and random classified into 3 equal groups (n =10): Group (A) (VC): patients receiving hybrid Ti base abutments (Variobase, Straumann, Switzerland) with cement-retained crowns, Group (B) (VS): patients receiving hybrid Ti base abutments (Variobase) with screw-retained crowns, Group (C) (DS): patients receiving non-segmented screw-retained crown (cemented onto Dess Ti Base). The monolithic zirconia crowns were CAD/CAM fabricated, cemented, and evaluated at baseline, 3, 6, 12 and 18 months clinically and radiographically. All data were collected and statistically analyzed.
Results: All 30 implants remained stable and reached osseointegration (100% cumulative success rate ⁅CSR⁆). The highest mean average crestal bone level (BL) measured 1.23+0.72mm (median: 1.40mm, range: 0.00-2.25mm) (P=0.09 NS) in group (C) (DS), and the least mean BL measured 1.00+0.55mm (median: 1.10mm, range: 0.00-2.00mm) and (median: 1.00mm, range: 0.10-1.90mm) (P=0.83 NS) and (P=0.52 NS) in the groups (B and A) (VS and VC) respectively.
Conclusions: Under the conditions of this study, using a prefabricated (Variobase or Dess) Ti base as an abutment for an implant-supported zirconia crown is an alternative procedure for FPDs. It promotes healthy and stable hard and soft tissues.