Journal of Prosthetic Dentistry
Clinical Research| Volume 123, ISSUE 2, P246-251, February 2020

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Clinical outcomes of using a prosthetic protocol to rehabilitate tissue-level implants with a convergent collar in the esthetic zone: A 3-year prospective study


      Statement of problem

      Whether increasing the space for peri-implant soft tissues by using implant systems with conical or convergent transmucosal components would improve tissue stability and esthetics is unclear.


      The purpose of this prospective clinical study was to evaluate the clinical and esthetic outcomes of using tissue-level implants with a convergent collar in the esthetic zone that had been rehabilitated following the biological oriented preparation technique (BOPT) approach after a 3-year follow-up period.

      Material and methods

      Sixteen participants with at least 1 nonrestorable tooth in the maxillary anterior region or with congenitally missing maxillary lateral incisors were enrolled, and tissue-level implants with a convergent collar were inserted 3 months after extraction. The implants were restored with cemented single crowns designed according to the BOPT protocol. Bone resorption and the pink esthetic score were evaluated over a 3-year period.


      Fifteen participants (mean age: 54.6 years) were evaluated over the 3-year period (total: 16 implants). One participant with 1 implant relocated dropped out of the study. The 3-year implant cumulative survival rate was 100%. The mean ±standard deviation bone-level change was 0.071 ±0.11 mm. The mean pink esthetic score was 8.5 ±1.59, range 4-10.


      The use of the BOPT protocol to restore tissue-level implants with a convergent collar achieved good esthetic results and maintained stable soft and hard peri-implant tissues.
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