An in vitro investigation into retention strength and fatigue resistance of various designs of tooth/implant supported overdentures

Abstract

Previously, the choice of prosthetic implant-retained overdentures has depended on data from previous studies about the retention-fatigue strength of the attachment system selected. Little or no data have been available on the correlation between the attachment system selected and the overdenture support configuration. The purpose of the present study was to evaluate the retention force and fatigue resistance of three attachment systems and four support designs of overdenture prosthesis. Four lower edentulous acrylic models were prepared and eight combinations of attachments groups were investigated in the study. These included: O-Rings with mini-dental implants (MDIs), Dalbo elliptic with Dalbo Rotex and fabricated flexible acrylic attachments with both MDI and Dalbo Rotex. The study was divided into four test groups: groups A and B, controls, and groups C and D, experimental groups. Control group A contained three overdenture supports: two free standing MDIs in the canine region and at the midline, and one simulated tooth root with Dalbo Rotex screwed in. Control group B contained four overdenture support foundations: two free standing MDIs in the right canine region and the first premolar region, and two simulated tooth roots with Dalbo Rotex screwed in at the same MDI position, but on the left side of the model. Experimental group C contained three overdenture support foundations: two free standing MDIs in the canine region and at the midline, and one simulated tooth root with MDI screwed in. Experimental group D contained four overdenture support foundations: two free standing MDIs in the right canine region and the first premolar region, and two simulated tooth roots with MDIs screwed in at the same MDI position, but on the left side of the model. Each group was further divided into two subgroups according to attachment type used. Five samples were prepared for each group. Retention force (N) values were recorded initially (0 cycles) and after 360, 720, 1440 and 2880 insertion and removal cycles. During the tensile test a cross-head speed of 10 mm/min was applied. Values of absolute force (AF) and relative force (RF) were statistically analyzed by two-way ANOVA and multiple comparison Tukey's tests between groups and cycles periods. The results of fatigue tests showed a 50% reduction in retention force in the subgroups with flexible attachments. A triangular design of overdenture support foundations with O-Ring attachments revealed the lowest value of AF and a relatively high reduction in RF. The four overdenture support designs with flexible acrylic attachments improved the retention force and reduced the fatigue retention. Furthermore, the results of the investigation demonstrate that flexible acrylic attachments for both teeth and implant-supported overdentures offer a wide range of retention forces.

Electromyography evaluation of masseter and temporalis, bite force, and quality of life in elderly patients during the adaptation of mandibular implant‐supported overdentures

“…Therefore, the aim of this study was to assess information on bite force, QoL, and SEMG during the rehabilitation process of edentulous individuals, replacing their conventional dentures for mandibular implant-supported dentures to assess whether this procedure would benefit them before the new dentures were installed. Different authors have reported results before and after the treatment realization, but none of them collected data during the clinical conduct (Mericske-Stern 1994; Bakke et al 2002;Dellavia et al 2007;Berretin-Felix et al 2008;Emami et al 2009Emami et al , 2015Caloss et al 2011;da Silva et al 2011;Dakhilalian et al 2012Dakhilalian et al , 2014Fatalla et al 2012;Geckili et al 2012b;Mumcu et al 2012;Preciado et al 2012;Awad et al 2014;Cakir et al 2014;De Rossi et al 2014;Boven et al 2015;Mundt et al 2015;Shaghaghian et al 2015).…”

Insertion and removal effects of tooth supported overdentures on retention strength and fatigue resistance of attachment systems: An in vivo study

“…However, constant repetitive stress as seen in fatigue test, [8][9][10] permanent deformation can occur.…”

A Three‐Dimensional Finite Element Analysis for Overdenture Attachments Supported by Teeth and/or Mini Dental Implants

“…The placement of dental implants in the optimum strategic position can create a favorable abutment situation, allowing for a variety of new prosthetic anchoring options for a removable prosthesis. 17 This treatment modality offers a viable new option, especially for elderly patients with few remaining functional residual teeth located unilaterally in an appropriate position. 18 In addition, this type of surgical intervention frequently represents minimal encumbrance and minimal invasiveness for those patients.…”