Clinical and esthetic outcomes of screw-retainedinternal-connection veneered zirconia-ceramic CAD-CAMabutments in single implant reconstructions: Five-year results ofa prospective case series investigation

Abstract

Purpose: To evaluate the long-term clinical performance and survival, as well as the biological, esthetic, and technical complications of one-piece, internally-connected, screw-retained, computer aided-design and computer aided-manufacturing (CAD-CAM) veneered zirconia anterior and posterior implant-supported single restorations fabricated on regular diameter implants.

Materials and methods: Following a 2-stage surgical procedure, 22 implants placed in anterior and posterior areas in 21 partially edentulous patients (mean age of 55 years; 9 males/12 females) were evaluated in terms of plaque index, pocket probing depth, bleeding on probing, level of oral hygiene, signs of mucositis/peri-implantitis, esthetic score, gingival zenith position, Papilla Index Score, thickness of peri-implant gingiva, radiographic marginal bone loss, and technical complications. Implants and restorations were prospectively followed from the insertion of the restoration (baseline), and up to 5 years postloading.

Results: After 5 years, radiological bone stability with no marginal bone loss (0.4 [0.4] vs. 0.5 [1.1] mm from 1- to 5-year follow-up) was recorded, with a 100% implant survival rate. Clinically, patients performed adequate oral hygiene, and tissues were kept healthy as determined by plaque index (PI) and oral hygiene index (OHI). The esthetic performance of the restorations revealed an increase in mucosal thickness from 3.2 (0.9) mm after 1 year to 3.3 (1.1) mm after 5 years, and a reduction in the gingival zenith position from 7.9 (1.5) mm after 1 year to 7.7 (1.5) mm at the 5-year recall examination. The prosthetic survival rate after 5 years was 78.9%, as 4 abutments fractured at different time points during the study. All abutment fractures occurred in the mandible, at the level of the second premolars and first molars.

Conclusions: After 5 years clinical function, Atlantis one-piece, screw-retained, internally connected CAD-CAM veneered zirconia implant-supported single crowns resulted in a relatively low survival rate, mainly associated with posterior single implant-supported reconstructions. However, due to the fact that the present clinical investigation used only one abutment design and reconstruction type, extrapolation of data to different implant systems, abutment designs, and reconstruction types must be cautious.