Tissue-level versus bone-level single implants in the anterior area rehabilitated with feather-edge crowns on conical implant abutments: An up to 5-year retrospective study.

STATEMENT OF PROBLEM: Limited information is available on the differences between tissue-level implants with an ultrathin threaded microsurface conical transmucosal portion and bone-level implants rehabilitated with conical custom abutments. PURPOSE: The purpose of this retrospective study was to assess the outcomes of crowns designed as per the biologically oriented preparation technique (BOPT) cemented on conical titanium abutments on tissue-level and bone-level implants. MATERIAL AND METHODS: Patients consecutively rehabilitated with a delayed loading protocol with anterior implant-supported single crowns with a feather-edge margin, in function for at least 4 years, were recruited and divided into 2 groups based on the implant type they had received: tissue-level implants with a conical transmucosal portion or bone-level implants rehabilitated with a conical abutment by following the platform switching concept. Bone resorption, pink esthetic score (PES), and white esthetic score (WES) were collected and analyzed. The nonparametric Mann-Whitney test was performed to analyze all parameters (alpha=.05 for all tests). RESULTS: A total of 43 participants (48 implants) were included in the present study. The mean follow-up period was 4.5 years (range 52-64 months). A statistically significant difference (P=.004) was found in the mean +/-standard deviation bone resorption between tissue-level implants (0.38 +/-0.46 mm) and bone-level implants (0.83 +/-0.58 mm). Higher values for both PES and WES were obtained in the tissue-level implant group. CONCLUSIONS: Within the limitations of the present retrospective study, tissue-level implants with a conical transmucosal portion seem to provide a suitable alternative to bone-level implants in the anterior area.