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Development trends of mucous-borne dentures in the aspect of elastomers applications

Dobrzańska-Danikiewicz A., Żmudzki J.

Archives of Materials Science and Engineering

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2012

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Vol. 55, nr 1

5-13

EN

Purpose: The aim of this study is to foreseen the influence of elastomers on the development of mucous-borne dentures in the aspect of bio-compatible use of prosthetic foundation tissue load bearing capacity. Design/methodology/approach: Multi-criteria comparative analysis based on the dendrological matrix of attractiveness and potential was used for the studies of denture solution and materials. There were differentiated seven groups of conventional dentures without an implantological stabilisation - the so-called hard dentures (CD) and those with a soft relining (CD-P), stabilized on one implant (SID) or on two implants (TID), that were differentiated as far as the denture attachment to implant was concerned. The first group was marked as "hard" (K) due to the used materials and inconsiderable lateral compliance. The elastomeric attachments (S) constituted the second group of attachments. Findings: In case of conventional dentures a significant influence of the relining on attractiveness was observed. In case of dentures retained on elastomeric attachments - they decided not only on the attractiveness, but they have also significantly increased dentures' potential. Research limitations/implications: Throughout the studies the variation of denture bearing structure materials were not taken into account, based on the assumption that acrylates are the most commonly used. Practical implications: The similar level of attractiveness of dentures retained on implants significantly varying as far as their construction is concerned shows that the focus should be mainly put on material design of elastomers' wearing characteristics. Originality/value: Multi-criteria heuristic analysis proved to be an effective tool for examination of dentures in the aspect evaluation of dentures material and cosntruction that show perspectives of the broadest use due to exploitation of the tissue bearing capability.

2

Silicone attachment for avoidance of bone tissue overloading in single implant-retained denture

Żmudzki J., Chladek G., Kasperski J.

Archives of Materials Science and Engineering

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2011

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Vol. 51, nr 2

107-115

EN

Purpose: The application of single implant-retained dentures (SIDs) is still rare. It seems that the reason of that is the fear of the overloading of a bone tissue around the implant that alone bears the occlusal loads. In this paper, stress level in the bone tissue around the single mini-implant that alone retained the lower denture was investigated. This stress level depends on the denture joint (the attachment) to the implant. Design/methodology/approach: 3D finite element method (FEM) analysis was used in order to determine the transmission of occlusal loads between mucous membrane foundation and the bone tissue around small diameter (1.8 mm) implant. Standard rotationally and axially mobile denture attachments were compared with the laterally compliant silicone attachment. Oblique mastication loads were assumed for the purposes of a better simulation of realistic conditions. Findings: Both types of standard attachments, rotationally and axially mobile, born remarkable values of oblique mastication force. This load results in a high stress in the bone tissue around a single mini-implant, in the area convergent with clinically observed “funnel-shaped” marginal bone loss around the implant neck. The silicone attachment reduced the loading to a level, which did not create any stress that would be dangerous for the bone tissue. Research limitations/implications: In the FEM model a perfect denture adherence to mucous foundation was assumed and a perfect joint between the implant and bone tissue. Further simplification were the linear isotropic characteristics of used materials. Practical implications: The use of single mini-implants requires the highest quality of the alloy and surface finishing due to the risk of fatigue cracks in case of a quickly progressing “funnel-shaped” bone loss. The silicone attachment provided better utilization of the mucous membrane support that significantly improves safety of implant and diminishes the requirements of bone foundation conditions for an implantological treatment. Originality/value: Presented was a possibility to achieve a much more reliable SID by means of used silicone attachment.

3

Loading of overdenture attachments under simulated biting forces

Żmudzki J., Chladek W., Krukowska J.

Archives of Materials Science and Engineering

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2008

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Vol. 32, nr 1

33-36

EN

Purpose: The basis for effectiveness evaluation of over-denture attachments is the determination of loads on supports, and denture mobility. In cases of denture stabilized on two prosthetic supports, for most of the attachments constructions that are available on the market, the margin of dentures mobility is limited to rotation around axes of the attachments. Design/methodology/approach: Determining attachments loadings during bearing of biting forces that accompany chewing processes was carried out by means of Finite Element Method model analysis. A three-dimensional model of a denture supported on mucous membrane and joint supports assumes to be fixed in places of denture anchoring to implants. This model was loaded on one side with unilateral oblique 100 N force at molars zone. Findings: Maximum loading at pillar accompanies biting forces acting in a lateral direction toward buccal side. Research limitations/implications: Researches were carried out exclusively for attachments not showing any resilience in any direction, without any rotational constrains. Hence, in further researches, at the first place, determined should be the influence of the vertical resiliency used in some of the commercial attachments on loads bearing. Practical implications: Appropriate determining of loadings levels on over-denture attachments, requires necessarily that the oblique biting forces will be taken into account. In case of an assumption of only vertically oriented biting forces, there is a significant underestimation of the most dangerous horizontal loadings of prosthetic supports. Originality/value: Presented displacements of denture and pillars loading as vertical and horizontal reactions causing pillar bending and leverage at the bone, constitute a starting point for evaluation of denture’s behavior and strength estimation of analyzed types of attachments for implants and the surrounding bone.