Maxillary overdentures supported by four or six implants in the anterior region; 1‐year results from a randomized controlled trial

Abstract

Objective: To compare a four-and six-implant maxillary overdenture after an observation period of 5 years. Material and methods: Fifty subjects with functional problems concerning their maxillary denture, who had ample bone volume in the anterior region to place four or six implants, were included and randomly assigned to either group. Implant and overdenture survival, clinical performance, marginal bone loss and patient satisfaction were assessed. Results: Forty-six patients completed the 5-year follow-up. One implant failed in the six implants group (99.2% survival) and none in the four implants group (100% survival). No overdentures had to be replaced during the observation period and the number of complications was limited. Clinical function was good, with no difference in clinical parameters between the groups. Mean marginal bone resorption was 0.50 AE 0.37 and 0.52 AE 0.43 mm in the four and six implant group respectively. Conclusion: In patients with functional complaints of their maxillary denture, bar-supported overdentures on four implants in the anterior maxillary region were not inferior to overdentures supported by six implants after 5 years of function. Implant survival and patient satisfaction were high, clinical parameters favourable, bone loss and complications to the denture were minor in both groups (Clinical trial registration number: NTR2969).

Comparative study of splinted and unsplinted implant-retained maxillary overdentures without palatal coverage: A literature review

“…The use of four splinted implants with bar has been used to support maxillary IODs and was considered a treatment of high implant survival rates [22][23][24][25]31], not achieving inferior results when compared to the same anchorage design supported by six maxillary implants. There was an indicative advantage in the use of four implants instead of six to reduce treatment costs [23,24].…”

“…Some studies presented a variable number of dental implants rating to four to six implants per patient [20][21][22][23][24][25][26] and others employed a fixed number like four [27,28] or six dental implants [29,30]. The same variation occurred to anchorage design.…”

“…The same variation occurred to anchorage design. The follow-up period ranged from twelve [23,24] to two hundred fifty eight months [31] in splinted design and forty eight [21] to one hundred seven months [26] in unsplinted design.…”

“…In total, 1626 implants were osseointegrated in 345 patient's maxillaries, excluding implants failures that occurred at healing phase, a total failure of 79 maxillary implants associated to the IODs without the palatal coverage was obtained. The general variation noted was 86.1% [30] to 100% [21][22][23][24][25] on the survival rate of maxillary dental implants. The maxillary implants survival rate in implant-supported overdentures (PR4) by four dental implants ranged from 96.7% [27] to 100% [21][22][23][24][25] and implant-retained and mucosupported (PR5) by four implants ranged from 95,5% [20] to 100% [21,25,26].…”

“…The number of implants placed to support IOD without palatal coverage in the studies and the number of implants lost were identified. Those articles that addressed a variation in the implants number installed in the IOD support, only five identified specifically the number of implant which failed [23,24,29,31] and one did not differentiated the number of implants lost [20]. …”