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Evaluation of the retention characteristics of various stud attachment systems for implant retained overdenture

Gonuldas F., Tokar E., Ozturk C.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 4

135--141

EN

The purpose of the study was to analyze and compare retention characteristics of different stud attachments including a standard and two low profile attachments on two implant embedded test models. Methods: Three different stud attachment systems (Ball attachment and two different low profile stud attachments – Equator and Locator) were used in this study. Two dental implants were placed vertically into a custom-made acrylic resin block within a 22 mm distance. Strong and soft nylon inserts of each attachment system were tested using cyclic dislodgement test for 24 months simulation. Maximum forces during the test were recorded and 10 consecutive data at baseline, 1st to 24th months were analyzed. Repeated measures ANOVA and post-hoc Tukey’s test ( p  0.05) were used for statistical analysis. Results: Retentive forces of the tested attachments varied from 30.7 to 93.75 N at the baseline. The highest initial mean retention (93.75 N) was observed in Group LC (locator attachment with clear nylon inserts) and the lowest initial mean retention (30.7 N) was detected in both Group BO (ball attachment with orange nylon inserts) and Group EY (equator with yellow nylon inserts). After the 24 months simulation, locator groups illustrated more light retention than other tested attachment systems. Conclusions: All tested attachment systems showed a significant decrease in retention value at the end of the simulated period. The locator attachment had significantly higher reduction in retention values compared to other low profile stud attachment equator and ball attachment.

2

Influence of introducing silver nanoparticles on tribological characteristics of soft liner

Chladek G., Żmudzki J., Malara P., Dobrzański L., Krawczyk C.

Archives of Materials Science and Engineering

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2013

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Vol. 62, nr 1

5--14

EN

Purpose: of this paper is to assess the influence of introducing silver nanoparticles to the material intended for denture lining on tribological properties of obtained composite and retention properties of elastic friction attachments made of it. Design/methodology/approach: Studies of coefficient of frictions and forces conducted using a handle designed for this which allows exerting symmetrical pressure through elastomer samples on counterspecimen, applying different pressure forces and relative velocities of friction elements. The study of forces and retention of elastic friction attachments was conducted on the basis of our own methodology in an environment of artificial saliva. Findings: Results of laboratory tests show that introducing 40 ppm of nanosilver does not influence coefficient of friction values. Simultaneously, some dependencies of coefficient of frictions on pressure forces values were observed, while no dependencies of coefficient of frictions on relative velocities of friction elements were shown. No practically meaningful influence of introducing nanosilver, pressure force or relative velocities of elements on friction force values was noted. Values of retention forces did not depend on the content of nanosilver. Research limitations/implications: Limitations resulting from the specificity of the conditions of laboratory tests of retention characteristics do not allow to fully translate obtained results to expected results of clinical trials. Practical implications: The studies show that introducing a small amount of nanosilver to soft lining material will allow to obtain elastic attachments with unchanged retention characteristics, but they will be characterized with increased antimicrobial resistance. Originality/value: Study results of tribological properties of a new composite were presented. Own methodology of studying coefficient of friction and friction force of silicone rubber was presented here.

3

Examinations on retention of overdentures with elastic frictional attachments

Chladek W., Chladek G., Wrzuś-Wieliński M., Żmudzki J.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 43, nr 1

205-213

EN

Purpose: of this paper was to evaluate the effectiveness of the overdentures equipped with silicone elastic frictional attachments. Design/methodology/approach: The examinations of retention characteristics of traditional attachments, elastic frictional attachments and models of overdentures have been carried out using Zwick testing machine. Retention forces and work essential for separating the attachments have been determined as well. Next the force – displacement characteristics for overdenture model have been registered for two places where the force was applied and for three inclination angles of the line of application of force. Findings: The obtained results of laboratory examinations gave evidence of high effectiveness of elastic frictional attachments. Research limitations/implications: It has not been possible to register mechanical characteristics due to limitations of clinical conditions. Wide analysis of retention characteristics requires examinations carried out in laboratory conditions. Practical implications: Thorough analysis of force - displacement characteristics enables to understand better the mechanisms which are essential for the effectiveness of particular attachments. Applying such knowledge in practice helps to use more effectively the properties of silicone rubbers for making the elastic frictional attachments. Originality/value: The presented method of evaluating the effectiveness of attachments is based on determining retention work of the attachments and it allows to compare quite objectively even relatively different solutions. The so far used criterion of measuring vertical retention force makes it possible to compare only the solutions which are based on similar mechanical principles.

4

The evaluation of selected attachment systems for implant-retained overdenture based on retention characteristics analysis

Chladek G., Wrzuś-Wieliński M.

Acta of Bioengineering and Biomechanics

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2010

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Vol. 12, no. 3

75-83

EN

The results of mechanical characteristics of attachments used for retaining and stabilizing overdenture have been analysed. Two commercially used attachments (a ball attachment and a bar attachment) and elastic frictional attachments designed by the research team with Professor Chladek as the leader have been investigated. The diagrams of force–displacement characteristics have been registered. Retention forces (FR) have been determined and total work (WT) disconnecting the attachments has been calculated on the basis of these diagrams. The analysis of total work corresponding to different types of attachments made it possible to distinguish some characteristic areas which illustrate specific features of particular designs. It has been revealed that determining the retention force allows us to compare only the attachments which work on similar bases. In order to conduct a purely objective comparison of the efficiency of different designs, it is necessary to analyze complete force–displacement characteristics as well as to determine on this basis the subsequent phases of separating the parts of attachments and to find the value of the work which in fact determines their quality. The comparison of selected commercially used designs and the presented elastic frictional attachments (taking into account the criterion of work) gives clear evidence that the introduced design of attachment enables us to create very good conditions of retaining overdenture.

5

Attachments of implant retained tissue supported denture under biting forces

Żmudzki J., Chladek W., Krukowska J.

Archives of Computational Materials Science and Surface Engineering

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2009

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Vol. 1, nr 1

13-20

EN

Purpose: In implant retained soft tissue supported type dentures functioning of attachments, presented by their producers as mechanically bio-compatible because of the ensured freedom of rotational displacements is accompanied by numerous problems that seem to be caused by excessive bearing of occlusal loads. Design/methodology/approach: For the purposes of attachments loadings evaluation, built was a threedimensional FEM model of a denture situated on an atrophic prosthetic foundation with joint supports assumed in the area of denture attachment to implants. Analysis of attachments loadings has been carried out under unilateral oblique occlusal forces of 100N in molars and incisors zones. Findings: Used methodology made it possible to determine attachments loading in a quantitative manner. In spite of free rotational movements implantological supports bear significant part of horizontal occlusal forces components, which reach the value of 66N during chewing processes. Research limitations/implications: Examined was only the most commonly used type of attachments. Hence, further studies, apart from constrains enabling rotational movements introduced should be also an axial compliance which is already offered by some types of attachments, and which additionally enables sedimentation of the denture towards the axes of implants. Practical implications: Analysis of loadings related to implantological attachments in case of assuming only a vertical component of occlusal forces leads to a significant underestimation of implantological supports loads values. In the presented analysis, taking into account the influence of the obliquely acting occlusal forces that occur in real chewing conditions, it has been proved that freedom of rotational movements of overdenture's attachments does not allow to use the natural supports of mucous membrane. That explains the reason of attachments and acrylic resin dentures damages, as well as the significant number of lost implants of upper denture resulting from biomechanical causes. In clinical practice, achieved should be the most anterior implants' placement, and especially in case of flat ridges because of the lack of any bearing surface. Originality/value: Determined loadings of supports might constitute a starting point for further biomechanical evaluation of attachments solutions that function according to similar principles, without the necessity of building complex models of the whole system.

6

Durability evaluation of a friction couple intended for implantological stabilization of complete dentures

Chladek G.

Acta of Bioengineering and Biomechanics

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2008

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Vol. 10, nr 3

7-12

EN

The paper presents the results of the study of the titanium implant–elastomeric membrane attachment, conducted from the point of view of potential utilization of the results in forecasting the durability of retention elements representing a new solution of dentures based on implants. The examination was carried out using a device designed by the author, which allowed the simulation of the process of inserting and removing dentures. Titanium counter specimens, simulating implants, were subjected to surface modification through their sandblasting with 350 ěm and 500 ěm abrasives, so as to diversify their roughness. The elastomeric membranes constituting a retention element of the attachment were made of a silicone material, Molloplast B. The influence of the number of cycles (one cycle meaning one insertion and removal of a denture) on the attachment’s retention force was studied. In order to better reflect the natural conditions, the device was equipped with a chamber which made it possible to perform the examination in an artificial saliva environment. The study has shown that the application of the polymer material Molloplast B for constructing the new type retention elements of dentures based on implants ensures practically constant values of the attachment's retention force in the required 6-month utilization period. After the time of denture usage, being eight times longer than originally assumed, the loss of retention force does not exceed 43% in any of the attachments investigated and the retention force values still allow the attachments to operate, although their effectiveness is partly reduced.