Purpose: The aim of the present study was to examine the retention force of monolithic zirconia copings cemented with various temporary cements on implant abutments in vitro.
Methods: Sixty exercise implants with pre-screwed implant abutments were embedded in resin. Subsequently, 60 CAD/CAM manufactured zirconia copings were divided into three main groups [Harvard Implant Semi-permanent (HAV), implantlink semi Forte (IMP), Temp Bond NE (TBNE)]. The zirconia copings were cemented on the implant abutments and loaded with 35 N. Specimens were stored in distilled water (37 °C) for 24 h. Half of the test specimens of each group were subjected to a thermocycling (TC) process. Retention force was measured in a universal testing machine. Using magnifying glasses, the fracture mode was determined. Statistical analysis was performed applying the Kruskal-Wallis test, the post hoc test according to Dunn-Bonferroni and a chi-square test of independence.
Results: Without TC, IMP showed the highest retention of the three temporary luting agents (100.5 ± 39.14 N). The measured retention forces of IMP were higher than those of HAV (45.78 ± 15.66 N) and TBNE (61.16 ± 20.19 N). After TC, retention was reduced. IMP showed the greatest retentive strength (21.69 ± 13.61 N, three fail outs). HAV and TBNE showed pull-off forces of similar magnitude (17.38 ± 12.77 N and 16.97 ± 12.36 N, two fail outs). The fracture mode analysis showed different results regarding the tested cements before and after TC (facture type before/after TC): IMP (III+II/III), HAV (I/II) and TBNE (III/III). There were clear differences of the fracture modes regarding the examination before and after TC.
Conclusions: Within the limits of this study, IMP showed the highest pull-off forces under the chosen test conditions. All three temporary luting agents showed lower retention forces after TC. Retention values in the individual cement classes were very heterogeneous. Easy cement removal in the crown lumen favours the dominance of adhesive cement fractures on the abutment and adhesive/cohesive cement fractures on the abutment with HAV appears advantageous in case of recementation of the superstructure.
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http://dx.doi.org/10.1186/s40729-021-00349-4 | DOI Listing |
Cureus
October 2024
Department of Prosthodontics, Maharaja Ganga Singh Dental College and Research Centre, Sri Ganganagar, IND.
Introduction: The marginal fit of dental restorations is essential for longevity and effectiveness of fixed prostheses, particularly single-unit crowns. Direct digital scanning offers significant advantages over indirect methods, providing a non-invasive, accurate, and reproducible means to evaluate marginal fit. This study aimed to assess the marginal fit of single-unit copings fabricated using computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia, direct metal laser sintering (DMLS), and porcelain-fused-to-metal (PFM) utilizing direct three-dimensional (3D) scanning.
View Article and Find Full Text PDFEur J Prosthodont Restor Dent
November 2024
Center for Dental Medicine, Clinic of Masticatory Dysfunction and Dental Biomaterials, University of Zurich, Zurich, Switzerland.
Aim: To compare the tensile strength, dislodgement forces, marginal gap and failure types between digitally fabricated zirconia root copings and conventionally manufactured cast gold root copings.
Methods: Extracted human teeth (N=30) were prepared for the root copings and randomly divided into 2 groups: (1)zirconia root copings(ZC) and gold root copings(GC). The specimens were tested for tensile bond strength and dislodgement forces in a universal testing machine and the types of the coping failures modes were analyzed.
Objective: The purpose of this study was to assess the accuracy of full coverage crowns produced by two manufacturing methods: additive 3D printing and subtractive milling utilizing three different predefined cement spaces.
Materials And Methods: Six groups were allocated based on the manufacturing method and the predefined cement space: printed wax with a 20 µm space (PW1); printed wax with a 50 µm space (PW2); printed wax with a 100 µm space (PW3); milled wax with a 20 µm cement space (MW1); milled wax with a 50 µm cement space (MW2); milled wax with a 100 µm cement space (MW3); milled zirconia coping with a 20 µm cement space (MZ1); milled zirconia coping with a 50 µm cement space (MZ2); milled zirconia with a 100 µm cement space (MZ3). All fabricated specimens were scanned using an Identica Blue 3D scanner and saved as standard tessellation language (STL) files.
Int J Dent
October 2024
Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, Heidelberg, Germany.
To evaluate the fracture resistance of veneered incisor crowns made from highly translucent zirconia frameworks. Ninety-six all-ceramic single crowns were based on either a coping with minimum wall thickness or a cutback framework fabricated from highly translucent zirconia (5Y-PSZ). Each one-third of the specimens was finalized with different veneering ceramics using standardizations and glaze firing.
View Article and Find Full Text PDFBMC Oral Health
September 2024
Prosthodontics Department, Faculty of Dentistry, Pharos University, Alexandria, Egypt.
Background: The purpose of this study was to evaluate the effect of using different types of metallic and non-metallic telescopic crown attachment materials on wear resistance and surface tomography changes in implant-retained mandibular overdentures.
Materials And Methods: Completely edentulous mandibular epoxy models were fabricated, in which two implants were placed in the canine region and retained to the implants with three different material combinations used for the construction of telescopic attachments. Thirty-three identical mandibular overdentures were fabricated using the conventional standardized technique.
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