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.
Highlights
Different attachment systems (AS) with varied prosthodontic designs and materials are used as primary or secondary retention devices in removable mandibular overdenture, retained or stabilized on implants [1–6]
All AS for IRMO are composed of one male part, the patrix—an abutment connected to the implant—and one female part, the matrix—composed of a housing included in the the intaglio surface of removable denture containing replaceableretention retentiondevice device (RD)
This review compares the most common ball attachment system (BAS) and Cylindrical attachment systems (CAS) used for 1- or 2-IRMO by assessing different criteria—
Summary
Different attachment systems (AS) with varied prosthodontic designs (stud, bar, magnet, double crown) and materials (metal and polymer) are used as primary or secondary retention devices in removable mandibular overdenture, retained or stabilized on implants [1–6]. A more cost-effective alternative consists of an overdenture stabilized by a single midline symphysis implant (1-IRMO) [3,4]. IRMO is more cost-effective than a conventional prosthesis, it requires significant clinical maintenance because of wear-related retention loss of its AS and clinical needs of maintenance [5,13]. All AS for IRMO are composed of one male part, the patrix—an abutment connected to the implant—and one female part, the matrix—composed of a housing included in IRMO is more cost‐effective than a conventional prosthesis, it requires significant clinical maintenance because of wear‐related retention loss of its AS and clinical needs of maintenance [5,13]
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