Partial Extraction Therapy: A Review of Human Clinical Studies
Partial extraction therapy (PET) is a collective concept encompassing a group of surgical techniques including socket shield, root membrane, proximal shield, pontic shield, and root submergence. PET uses the patient's own root structure to maintain blood supply derived from the periodontal ligament complex to preserve the periodontium and peri-implant tissues during restorative and implant therapy. This review aims to summarize the current knowledge regarding PET techniques and present a comprehensive evaluation of human clinical studies in the literature. Two independent reviewers conducted electronic and manual searches until January 1, 2021, in the following electronic bibliographic databases: PubMed, EMBASE, and Dentistry & Oral Sciences Source. Gray literature was searched to identify additional candidates for potential inclusion. Articles were screened by a group of 4 reviewers using the Covidence software and synthesized. A systematic search of the literature yielded 5714 results. Sixty-four articles were selected for full-text assessment, of which 42 eligible studies were included in the review. Twelve studies were added to the synthesis after a manual search of the reference lists. A total of 54 studies were examined in this review. In sum, PET techniques offer several clinical advantages: (1) preservation of buccal bone postextraction and limitation of alveolar ridge resorption, (2) mitigation of the need for invasive ridge augmentation procedures, and (3) soft-tissue dimensional stability and high esthetic outcomes. Further randomized clinical studies with larger sample sizes are needed to improve the understanding of the long-term clinical outcomes of PET.
Flow diagram of the systematic search strategy used for the literature review and retrieval.
Diagram of the socket shield or root membrane technique from the (a) occlusal view and (b) proximal view. A root fragment is intentionally retained on the buccal aspect of the socket prior to immediate implant placement with the aim of preserving buccal bone and achieving optimal esthetics.
Diagram of the proximal shield technique from the (a) occlusal view and (b) proximal view. A root fragment is intentionally retained on the proximal aspect of the socket prior to immediate implant placement with the aim of preserving periodontal support for the interproximal papilla.
Diagram of the pontic shield technique from the (a) occlusal view and (b) proximal view. A root fragment is intentionally retained on the buccal aspect of the socket with the aim of preserving buccal bone for pontic site development.
Diagram of the root submergence technique from the (a) occlusal view and (b) proximal view. Decoronation is performed and the root is intentionally retained with the aim of preserving the alveolar ridge for pontic site development or maintenance of ridge-support for dentures.
Contributor Notes