Overdentures Versus Fixed Prostheses

Two concepts of prosthetic restorations exist for the edentulous jaw: the fixed prosthesis (mostly screw retained) and the overdenture. It appears that overdentures are preferably placed in old patients and in compromised situations. Since the eighties, a series of studies - including longterm results - have demonstrated the reliability of treatment with fixed prostheses for the upper and lower jaw. An increasing number of studies on mandibular overdentures supported by only two implants give evidence of the effectiveness of this treatment modality. Comparable data for maxillary overdentures are still missing. While dentists tend to base the selection of the prosthetic design on the number of implants that can be placed, other criteria have to be considered: esthetic appearance, facial morphology and restitution of lost hard and soft tissues, costs of implant-prosthodontic treatment, stability of the prostheses, complications and adjustments required, assessment of individual needs. From an economic point of view overdentures supported by two to four implants might be preferred. Prosthetic methods in general and related to implants are not evidence based. They relay on clinical experiences, patients’ demands technical considerations and reports of success and failure. However, from clinical experience, well-designed clinical concepts have evolved and the benefit of the patients concerned appears to be high and obvious. The lecture will discuss the use of implants for prosthodontic rehabilitation in the completely edentulous jaw. Indications and various types of removable prostheses are presented and variations of design discussed. Biomechanical aspects of fixation and stabilization of prosthesis complete the overview

Number of implants placed for complete‐arch fixed prostheses: A systematic review and meta‐analysis

Objectives The main purpose of this systematic review was to evaluate outcomes related to the number of implants utilized to support complete‐arch fixed prostheses, both for the maxilla and the mandible. Materials and methods This review followed the reporting guidelines of the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA). A focused question using the PICO format was developed, questioning whether “In patients with an implant supported fixed complete dental prosthesis, do implant and prosthetic survival outcomes differ between five or more compared to fewer than five supporting implants?”. A comprehensive search of the literature was formulated and performed electronically and by hand search. Two independent reviewers selected the papers and tabulated results. Primary outcomes analyzed were implant and prosthesis survival. Implant distribution, loading, and type of retention were observed as secondary outcomes, as they relate to the number of implants. A meta‐analysis was performed to compare results for studies by number of implants. Results The search strategy identified 1,579 abstracts for initial review. Based on evaluation of the abstracts, 359 articles were identified for full‐text evaluation. From these, 93 were selected and included in this review, being nine RCTs, 42 prospective and 42 retrospective. Of the 93 selected studies, 28 reported number of implants for the maxilla, 46 for the mandible, and 19 for both maxilla and mandible. The most reported number of implants for the “fewer than five” group is 4 for the maxilla, and 3 and 4 for the mandible, whereas for the “five or more” implants group, the most reported number of implants was 6 for the maxilla and 5 for the mandible. No significant differences in the primary outcomes analyzed were identified when fewer than five implants per arch were compared with five or more implants per arch (p > 0.05), in a follow‐up time ranging from 1 to 15 years (median of 8 years). Conclusions Evidence from this systematic review and meta‐analysis suggests that the use of fewer than five implants per arch, when compared to five or more implants per arch, to support a fixed prosthesis of the completely edentulous maxilla or mandible, present similar survival rates, with no statistical significant difference at a p < 0.05 and a confidence interval of 95%

Prosthetic considerations

Implants have changed prosthodontics more than any other innovation in dentistry. Replacement of lost teeth by a fixed or removable prosthesis is considered to be a restitutio ad similem, while implants may provide a feeling of restitutio ad integrum. Implant prosthodontics means restoring function, aesthetics, and providing technology; biology and technology are combined. Placement of implants is a reconstructive, preprosthetic surgical intervention and is therefore different from most goals in oral surgery that consist of tooth extraction, treating infection and removing pathology from soft or hard tissues. Thus, implants are part of the final prosthetic treatment which encompasses functional, aesthetic and social rehabilitation. The patient's needs and functional status determine the goal of prosthetic treatment. Treatment outcomes in implant prosthodontics are survival of implants and prostheses, impact on physiological and psychological status, oral health-related impact on quality of life, and initial and maintenance costs. A variety of prosthetic solutions are available to restore the partially and completely edentulous jaw and more recently specific methods have been developed such as computer guided planning and CAD-CAM technologies. These should allow more uniform quality and passive fit of prostheses, and simultaneously enables processing of biologically well-accepted materials