PEEK Primary Crowns with Cobalt-Chromium, Zirconia and Galvanic Secondary Crowns with Different Tapers—A Comparison of Retention Forces

Abstract

In prosthetic dentistry, double crown systems have proved their suitability as retainers for removable partial dentures. However, investigations in this context, regarding polyetheretherketone, are scarce. Therefore, the aim of this study was to test the retention force (RF) between polyetheretherketone (PEEK) primary and cobalt-chromium (CoCr), zirconia (ZrO2) and galvanic (GAL) secondary crowns with three different tapers. Primary PEEK-crowns were milled with the tapers 0°, 1°, and 2° (n = 10/taper, respectively). Afterwards, 90 secondary crowns were fabricated: (i) 30 CoCr-crowns milled from Ceramill Sintron (AmannGirrbach, Koblach, Austria) (n = 10/taper), (ii) 30 ZrO2-crowns milled from Ceramill ZI (AmannGirrbach, Koblach, Austria) (n = 10/taper), and (iii) 30 GAL-crowns made using electroforming (n = 10/taper). RF was measured in a pull-off test (20 pull-offs/specimen) and data were analyzed using 2-/1-way Analysis of Variance (ANOVA) followed by the Tukey-Honestly Significant Difference (HSD) post hoc test and linear regression analyses (p < 0.05). The measured mean RF values ranged between 9.6 and 38.2 N. With regard to the 0°, 1°, and 2° tapered crowns, no statistically significant differences between CoCr and ZrO2 were observed (p > 0.141). At 0° taper, no differences in retention forces between GAL, CrCr, and ZrO2 crowns were found (p = 0.075). However, at 1° and 2° taper, lower RF for GAL-crowns were observed (p < 0.009, p < 0.001, respectively). According to this laboratory study, PEEK might be a suitable material for primary crowns, regardless of the taper and the material of secondary crown. Long-term results, however, are still necessary.

Retention force of overdenture retained with telescopic crowns: A comparison of polyether ether ketone and zirconia ceramic telescopic crowns

“…The possible explanation may be that known recommendation not to polish inner surfaces of PEEK crowns contributes to an initial high abrasiveness and consequently robust initial retentive force values. In addition to that, PEEK as a flexible material undergoes the process of better adaptation to the primary coping [9,10,11]. The results concerning the second hypothesis showed that final pull-off forces were 4.1 N and 3 N, respectively for each group.…”

“…The primary crowns were polished with a special bur kit for zirconia (sets 4430 and 4431, Komet Dental Gebr. Brasseler GmbH & Co. KG, Lemgo, Germany) with water cooling using a hand piece [9].…”

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.…”

“…Telescopic crowns on implants are effective in prosthesis stabilization with regard to horizontal forces in cases of advanced atrophy of the alveolar crest [4,19] . It was revealed that the variation in the results is not only material related, but also related to the manufacturing techniques [4] .…”

“…Whereas the hardness of 1ry crown (metal) (455.88 HV) is more than that of the 2ry crown (PEEK) (110 HV), therefore, the use of a hard and wear-resistant primary crown material against a less hard secondary crown material is advantageous. Thus, the adaptation between primary and secondary crowns will be achieved by the changes in the fitting surface of the secondary crown [4,5] .…”