Retention force measurement of telescopic crowns

Abstract

This study deals with the determination of the retentive force between primary and secondary telescopic crowns under clinical conditions. Forty-three combined fixed-removable prostheses with a total of 140 double crowns were used for retention force measurement of the telescopic crowns prior to cementation. The crowns had a preparation of 1-2°. A specifically designed measuring device was used. The retentive forces were measured with and without lubrication by a saliva substitute. The measured values were analyzed according to the type of tooth (incisors, canines, premolars, and molars). Additionally, a comparison between lubricated and unlubricated telescopic crowns was done. As maximum retention force value 29.98 N was recorded with a telescopic crown on a molar, while the minimum of 0.08 N was found with a specimen on a canine. The median value of retention force of all telescopic crowns reached 1.93 N with an interquartile distance of 4.35 N. No statistically significant difference between lubricated and unlubricated specimens was found. The results indicate that retention force values of telescopic crowns, measured in clinical practice, are often much lower than those cited in the literature. The measurements also show a wide range. Whether this proves to be a problem for the patient's quality of life or not can however only be established by a comparison of the presented results with a follow-up study involving measurement of intraoral retention and determination by e.g. oral health impact profile.

The Evaluation of Changes in Retention Force Values in Three-Element Telescopic Crown Systems using Simulated Load Cycles

“…This phenomenon explains the strain of the surface of the crown depends on the malleability of materials use. This phenomenon is characteristic especially for crowns made of gold alloys, where the observed initial decrease in the value of the retention force is momentarily stabilized until another decline in value and eventual complete loss of retention [1,31,32,35,36]. In this study the initial phase in all groups was in the range of 0-2500 cycles, followed by a period of relative stabilization of the value of the retention force in the range of 30000 cycles.…”

“…The retention value obtained in the study of a single support tooth cannot refer to the final retention of the prosthesis based on it, especially if there are other support teeth provided with telescopic crowns. Retention of the prosthesis based on more than one telescopic crown is not a simple sum of the individual pillars and the retention does not correlate with their number [35].…”

“…The most important factors include the tribochemical impact, abrasion, adhesion, and defects within the surface. These factors can occur separately or overlap, which can be related to the state of material and construction of the retention element [34][35][36].…”

“…Retention telescopic crowns are associated with the contact surface of the crown in the system and it depends on many factors, mainly the geometry of the crown and the type of material used to make the crowns [28][29][30][31][32][33][34][35][36][37][38]. The developments of materials and new technologies that can be used in dental prosthetics create the prospects of the appearance of new design concepts and materials in the near future.…”

A Systematic Review Studying the Effect of Different Framework Materials on the Retention of Implant Telescopic Overdentures.

“…After initial titles and abstracts screening , 701 irrelevant articles were excluded and a total of 41 articles were selected for full-text screening, 2 additional articles were found through hand searching [4,5] . After full text screening, 15 articles [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] were included in the present analysis.…”