Journal of Prosthetic Dentistry

Evaluation of a shape memory implant abutment system: An up to 6-month pilot clinical study

  • Kumar C. Shah
    Corresponding author: Dr Kumar C. Shah, Division of Advanced Prosthodontics University of California Los Angeles 10833 LeConte Avenue, B3-087 CHS, Los Angeles, CA 90095-1668
    Associate Clinical Professor, Division of Advanced Prosthodontics and Director, Advanced Prosthodontics Residency Program, University of California Los Angeles School of Dentistry, Los Angeles, Calif
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  • Chase S. Linsley
    Assistant Adjunct Professor, Bioengineering, University of California Los Angeles, Los Angeles, Calif
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  • Benjamin M. Wu
    Professor and Chair, Division of Advanced Prosthodontics and Bioengineering, Materials, Science, and Orthopedic Surgery, University of California Los Angeles, Los Angeles, Calif
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      Statement of problem

      Screw- and cement-based retention mechanisms are used to attach prostheses to dental implants; however, each approach can lead to clinical complications such as crown fracturing or peri-implantitis. A novel abutment and prosthesis retention system has been engineered to achieve the esthetics and retention force of cement-based fixation while maintaining the retrievability of screw-retained restorations.


      The purpose of this pilot clinical study was to evaluate the effectiveness of this innovative retention system on posterior tooth restorations.

      Material and methods

      This clinical study, with up to 6 months of follow-up, included 8 participants with posterior osseointegrated implants who met the eligibility criteria to receive the abutment and shape memory sleeve. Radiographs were used to evaluate crown seating. Crown stability was measured using the Periotest, and occlusal analysis was performed using the Tekscan system and shimstock. Peri-implant health was evaluated by probing, and the plaque and gingival indices were recorded. In addition, patient-reported outcomes were recorded.


      Minimal differences were observed between baseline and endpoint assessment of the plaque and gingival indices, probing depth, and proximal and occlusal contacts. There were no patient-reported problems or complaints about discomfort. The overall peri-implant health remained unchanged from the baseline evaluations for all participants. Proximal contact around the restoration was present at the baseline and at the conclusion of the study for 7 of the participants. Occlusal contact was observed to be either light (5 participants) or holding (3 participants). In addition, visual inspection of retrieved crowns revealed clean surfaces free of macroparticle ingress, and bacterial accumulation at the coping-abutment interface was not detected.


      The safety and efficacy findings of this pilot clinical study suggest that this new shape memory alloy–based retention system may provide a suitable alternative for implant prosthodontics. The retention system allowed for easy prosthesis seating and retrieval.
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