Effect of implant support on distal extension removable partial dentures: in vitro assessment

Abstract

The implants in implant-supported removable partial dentures (RPDs) are placed in the edentulous ridge to stabilize the RPD and minimize the resultant rotational movement. This study investigated the effect of implant placement on RPD stability. A model simulating a mandibular bilateral distal extension missing was fabricated using epoxy resin and silicone impression material as thin (1 mm) and thick (2 mm) soft tissues. Five pressure sensors (PS-10K, Kyowa, Tokyo, Japan) were attached near the left and right first molars (#36 and #46), first premolars (#34 and #44) and medio-lingual alveolar crest. Five bilateral distal extension RPDs with Co-Cr frameworks were conventionally fabricated. After the implants were placed at the bilateral second molar areas, healing caps (4.5 mm high) were connected to the denture base with autopolymerized resin to support the RPD. As in a conventional RPD, sealing screws were placed without connecting them. Loads up to 5 kg were applied, and the pressure and displacement of the RPDs (n = 5) were simultaneously measured and analysed using the Wilcoxen test (alpha = 0.05). There was less pressure on both thin and thick soft tissues, the #36, #46 and the medio-lingual alveolar crest from the implant-supported RPD than from the conventional RPD (P < 0.05). There were no significant differences in pressure on #34 and #44 between the two RPDs (P > 0.05). There was significantly less denture displacement of the implant-supported RPD than of the conventional denture (P < 0.05). Implant support helped prevent the displacement of distal extension RPDs and decreased the pressure on soft tissues.

Behaviour of Implant-Bearing Overdenture Materials with a Change in Number and Position Implants. What Happen with all on Four Protocols?

“…There is an absence of contrasted, and more long-term, evidence on the reduction or non-overloading of implant angulation, following the All on four protocols [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39].…”

“…It is demonstrated and is a biomechanical principle that the overall stress on the entire implant / peri-implant bone system is reduced by increasing the area on which the force is applied and the most effective method to achieve this is to increase the number of implant supports prosthesis. In general, although the number of implants may vary depending on the type of prosthetic restoration, other parameters such as factors of patient strength, quantity and bone quality, prosthetic space, nature 21 Patients with five years of use or without follow-up data in nine patients [5]. Even in a recent in vitro study it was shown that in both prostheses retained by one or two implants, lateral forces on the abutments were similar.…”

Prospective clinical study of prosthetic treatment outcome of implant-retained- removable-partial-denture during 5 year-follow-ups

“…Implants can be placed in the distalextension-areas for resolving these problems. [18][19][20][21][22][23][24][25][26] Patients and most clinicians generally prefer fixed prostheses. However, there are some situations in which IRRPDs may be considered as the only possible treatment option.…”

“…So that there is no need to sinus augmentation or nerve-repositioning-surgery, 10) Converting a Kennedy Class Ι or II RPD to a toothimplant-supported RPD which may be considered as a Kennedy Class III, 11) Psychological benefit of preserving patient's natural teeth with less than optimal prognosis, at least for an interim period, 12) A "staged" approach in implant insertion may be performed according to patient's budget, 3,14,18,20,[26][27][28][29][30] 13) Oral hygiene may be provided more easily than fixed prostheses and nocturnal bruxism can be reduced or eliminated due to its removal during night, 12,31 14) In the case of greater crown-height-space (CHS) resulting from excessive RRR, macrotrauma or ablative surgery, IRRPD seems to be a better biomechanical option. …”

Complication and management of implant-assisted removable partial denture with distal extension: a clinical report

“…And attachment can be connected to implant for retention and support in implant retained partial overdenture (IR-POD). 5,6 Although several retrospective ISRPD studies have shown a high survival rate of implant, some mechanical complications can occur. de Freitas et al 7 reported that ISRPD had a high success rate ranging from 95 -100% and good patient's satisfaction but showed several complications such as pitting of the healing abutment, replacement of resilient component of the attachment, damage in framework, screw loosening and damage in acrylic denture base.…”