Evaluation of Retention, Wear, and Maintenance of Attachment Systems for Single- or Two-Implant-Retained Mandibular Overdentures: A Systematic Review

Abstract

Attachment systems (AS) enhance retention and stability by anchoring the overdentures to implants. Since 2002, the McGill consensus statement recommends the 2-implant-retained overdentures as the standard choice for edentulous mandible (2-IRMO). Considering the large number of AS available, it remains difficult for a practitioner to make a reasoned choice. A systematic review was conducted in PubMed/Medline and carried out independently by three authors, on retention, wear, and maintenance of AS used clinically or in vitro specifically for 1- or 2-IRMO. The 45 selected studies include 14 clinical and 31 in vitro studies. The risk of bias was evaluated according to the revised Cochrane risk of bias tool for randomized trials (RoB 2). The initial retention force of the cylindrical system is higher than the ball system. The retention loss, related to the wear of the retention device, is responsible for the most common need of maintenance, requiring activation or replacement. Plastic retention devices wear out faster and more significantly than metal ones, implying a worse time behavior of cylindrical systems, but their maintenance rate is similar. Neither system appears categorically superior. Cylindrical systems provide higher initial retention than ball ones; this advantage reduces over time with wear without affecting their need for maintenance.

Effect of Implant Positions and Angulations on Retentive Strength of 2-Implant Mandibular Overdentures: An In Vitro Study with the New 3D-Printed Simulation Method

“…Greater retentive strength may also affect the longevity of the flexible matrix [ 6 – 9 ]. Maximum studies evaluated the retentive strengths of 2IMO after simulated function and very few evaluated the stresses at baseline without age simulation [ 9 , 11 – 15 ]. The attachments are serviceable from the first day of their usage in mouth; hence, the present study evaluated their retentive strength without any age simulation.…”

“…Further studies are advocated using different retentive elements like PEEK and polyvinyl siloxane. Wakam et al [ 15 ] carried out systematic review of 14 clinical and 31 in vitro studies regarding the retention, wear, and maintenance of attachments used clinically or in vitro specifically for 1IMO or 2IMO. They have concluded that the plastic retention devices wear out faster and more significantly than metal ones.…”

“…Many investors evaluated the effect of cyclic loading on stud attachment wear [9,[11][12][13][14][15] and initial retention was significantly higher than retention after wear or simulated clinical function under different number of insertion-removal cycles for different type of inserts. However, the literature lacks the information on the retentive strength of the attachments without insertion-removal cycles which simulates the overdenture usage from the first day.…”

“…e gingival and bleeding index of the patients were not influenced by any of the unsplinted attachments (stud, magnet, and telescopic) studied [16]. Most of these studies [11][12][13][14][15][16][17] used canine position as a standard position in 2IMO patients.…”

Total rehabilitation with implant-supported and implant-retained prostheses in atrophic maxillae: Aesthetic and functional resolution for totally edentulous patients

“…The costs for making an overdenture remain slightly below average when compared to an implant-supported fixed complete denture, however, the maintenance of an overdenture can occur on average after 12 months of prosthesis installation, and the main problems related to it are the loss of retention due to wear of the retention systems of the prosthesis (Wakam et al 2022).…”