Maxillary implant overdentures on two or four implants. A prospective randomized cross‐over clinical trial of implant and denture success and survival

Abstract

Objectives To determine implant survival and success of four conventionally but initially asynchronously loaded implants in implant‐supported overdentures for the edentulous maxilla, in participants with opposing mandibular two‐implant overdentures. Material and methods Twenty‐six participants received four implants in the region of the maxillary canines and molars. After healing, 24 of these participants (mean age: 68.3 years) were randomly allocated to one of two treatment groups, and the adapted overdenture was attached to two unsplinted cylindrical attachments. The other two matrixes remained unattached to the implants for 3 months. After this period, the other two implants were loaded for 3 months (cross‐over design). Then, all four implants were loaded for another 3 months. Kaplan–Meier curves were used to evaluate survival and success of implants and dentures. Results During the active prosthetic study phase, three participants lost one implant. Two participants lost three implants during the recall period. Implant survival after loading was 93.8% after a mean observation period of 3.1 years. Denture survival was 100%, but denture success was 95.8%, due to major prosthetic complications. Most participants preferred four implants to two. Conclusions Within the limitations of the study, it can be concluded that maxillary implant overdentures on two or four implants are both recommendable treatment options. Two posterior implants are not superior to two anterior implants under overdentures retained by unsplinted cylindrical attachments. Implant and prosthetic complications and aftercare measures are common but are mostly easy to handle. However, 23 of the 24 participants preferred the 4‐implant maxillary overdenture.

Maxillary overdentures supported by four or six implants in the anterior region: 10‐year randomized controlled trial results

“…Although two and four unsplinted implants, placed in the cuspid and molar region, to support a maxillary overdenture result in similar clinical outcomes in a crossover clinical trial, patients preferred four implants (Kappel et al, 2021 ). At least four implants are advised in a systematic review, with implants as well anteriorly and posteriorly (Messias et al, 2021 ), although short‐term results from a prospective study indicate that results with four unsplinted implants, placed in the cuspid and molar region, were less favourable (Bouhy et al, 2020 ).…”

Maxillary overdenture on three implants retained by low‐profile stud attachments – A prospective cohort study

“…While there is a lack of studies reporting on using three stud attachments with an anterior–posterior spread that creates a triangular support zone, several papers report using four stud attachments to create a quadrangular support zone. 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 Only one of these studies discussed the relevancy of implant number and forwarded the following: ‘Interestingly, the use of three implants may also provide sufficient retention to satisfy the patient during function, if the anterior‐posterior spread is large enough’. 40 …”

Impact of design elements of the implant supracrestal complex (ISC) on the risk of peri‐implant mucositis and peri‐implantitis: A critical review

“…Even so, defining the prevalence of peri-implantitis in crosssectional studies remains a significant challenge. Romandini et al (2021) have recently shown in a clinical study; the secondary case definition of peri-implantitis suggested by Berglundh et al (2018) to have a high level of specificity but low sensitivity. The authors deemed it necessary to exclude studies not reporting clinical outcomes measures of bleeding on probing, even if diagnosis of periimplantitis was suggested in order to compile the highest level of available evidence for a meaningful analysis.…”