The effect of the resilient-layer distal-extension partial denture on movement of the abutment teeth: A new methodology

Effect of material on stress transmission to the supporting structures in Kennedy Class I restored by Telescopic-retained Removable Partial Denture. (Strain Gauge Study)

“…It was used for this purpose because it has the lowest values of dimensional changes and permanent deformation, and requires less time to recover the visco-elastic deformation among all rubber impression materials. 48 Also in order to provide a stable non-movable model surface, an adhesive was used for bonding the silicone layer that simulated the oral mucosa to the underlying epoxy resin model. 55 Although the mechanical behavior of the PVS impression material, used to simulate the PDL invitro, is different from what is expected for the PDL in-vivo, the load applied to the prosthesis in this study was not load to failure so the influence of the supporting structures, including the PDL was considered to be minor.…”

“…It assesses strains induced into a loaded structure by changing the resistance of an electric wire, insulated by a packing material so as to be protected from humidity in order to obtain reliable recordings, 58,59 into strain measurement. 48 Moreover the use of in-vivo strain gauges comprises many shortcomings including, short circuits could not be prevented due to the difficulty in isolation of the gauges from saliva and blood, and the unavoidable patient movement resulting in motion of the wire that usually produces inaccurate results. Consequently, in-vitro strain gauge researches remain as valuable guides to the clinicians awaiting the feasibility to conduct such studies on large scale in order to have statistically concrete conclusions.…”

“…62 The design was the same for the two groups except that the major connector for the PEEK was lingual plate as recommended by the manufacturer as to increase the rigidity needed for its fabrication and thus limiting the possible difference in strains recorded to the type of material used. 48 Concerning the cementation of the telescopic retainers, the thickness of the cement layer used was kept minimum in order to avoid the effect of thick cement layer on the obtained data. 48 Unilateral and bilateral loads were applied.…”

“…48 Concerning the cementation of the telescopic retainers, the thickness of the cement layer used was kept minimum in order to avoid the effect of thick cement layer on the obtained data. 48 Unilateral and bilateral loads were applied. The load application sites for bilateral loading were adjusted using articulating paper to provide even and simultaneous loading on both sides of the partial denture.…”

“…46 However, strain gauge measurements were the adopted methodology in this study as they are the most accurate and widely used instruments to record surface stresses and to study the mechanics of prosthetic appliances in previous researches. [47][48][49] In the literature, there are contradictory results about the force-transmission characteristics of telescopic RPDs, and little is known about their forcetransmission patterns related to different material types, rigidity (rigid or resilient), and a number of abutments supporting such telescopic dentures. 50 Hence, it seemed of value to investigate the stresses induced mesial and distal to the abutments during unilateral and bilateral loading conditions, using two different materials; Co-Cr alloy and PEEK for telescopic-retained RPD fabrication.…”