Ammar T Kasem1, Amal A Sakrana2, Mohamed Ellayeh3, Mutlu Özcan4. 1. Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. 2. Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. 3. Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. 4. University of Zurich, Division of Dental Biomaterials, Center for Dental and Oral Medicine, Clinic for Reconstructive Dentistry, Zurich, Switzerland.
Abstract
OBJECTIVE: Currently, minimal invasive approaches combining less invasive finish line preparations and reduced ceramic thickness are required. The aim of this study was to evaluate the fracture resistance of two ceramic systems fabricated with two preparation designs using CAD/CAM standardization technology. MATERIALS AND METHODS: Forty intact human maxillary premolars were divided into two main groups according to the preparation technique. Group H (Horizontal): teeth with shoulder finish line and group V (Vertical): teeth with feather edge. Each main group was subdivided randomly into two subgroups according to the material used. Group CD (Celtra Duo) zirconia-reinforced glass ceramics and group K (KATANA) monolithic zirconia. CAD/CAM was used for standardization of natural teeth preparation. After cementation using self-adhesive resin cement, all specimens were subjected to 5000 thermal cycles and then were loaded until fracture. Failure types were evaluated using Stereomicroscopy and Scanning Electron Microscopy (SEM). RESULTS: Nonsignificant; the higher mean value was recorded with VCD group (482.5 ± 103.8 N) and VK group (1347.6 ± 177.4 N) vs HCD group (471 ± 107.6 N) and HK group (1255.6 ± 121.3 N). SEM findings showed that fractures occurred mainly at the occlusal side of the crowns. CONCLUSIONS: Vertical preparation showed a promising alternative to horizontal preparation. Moreover, both Celtra Duo and KATANA crowns can be used in premolar area with 0.5 mm margin thickness. CLINICAL SIGNIFICANCE: Zirconia-reinforced glass ceramic and monolithic zirconia crowns may not necessitate the preparation of invasive finish lines as the type of finish line did not impair the strength after aging conditions.
OBJECTIVE: Currently, minimal invasive approaches combining less invasive finish line preparations and reduced ceramic thickness are required. The aim of this study was to evaluate the fracture resistance of two ceramic systems fabricated with two preparation designs using CAD/CAM standardization technology. MATERIALS AND METHODS: Forty intact human maxillary premolars were divided into two main groups according to the preparation technique. Group H (Horizontal): teeth with shoulder finish line and group V (Vertical): teeth with feather edge. Each main group was subdivided randomly into two subgroups according to the material used. Group CD (Celtra Duo) zirconia-reinforced glass ceramics and group K (KATANA) monolithic zirconia. CAD/CAM was used for standardization of natural teeth preparation. After cementation using self-adhesive resin cement, all specimens were subjected to 5000 thermal cycles and then were loaded until fracture. Failure types were evaluated using Stereomicroscopy and Scanning Electron Microscopy (SEM). RESULTS: Nonsignificant; the higher mean value was recorded with VCD group (482.5 ± 103.8 N) and VK group (1347.6 ± 177.4 N) vs HCD group (471 ± 107.6 N) and HK group (1255.6 ± 121.3 N). SEM findings showed that fractures occurred mainly at the occlusal side of the crowns. CONCLUSIONS: Vertical preparation showed a promising alternative to horizontal preparation. Moreover, both Celtra Duo and KATANA crowns can be used in premolar area with 0.5 mm margin thickness. CLINICAL SIGNIFICANCE: Zirconia-reinforced glass ceramic and monolithic zirconia crowns may not necessitate the preparation of invasive finish lines as the type of finish line did not impair the strength after aging conditions.
Authors: Luigi Giovanni Bernardo Sichi; Fernanda Zapater Pierre; Laura Viviana Calvache Arcila; Guilherme Schmitt de Andrade; João Paulo Mendes Tribst; Pietro Ausiello; Alessandro Espedito di Lauro; Alexandre Luiz Souto Borges Journal: Molecules Date: 2021-10-10 Impact factor: 4.411
Authors: Sorin Gheorghe Mihali; Dan Lolos; George Popa; Anca Tudor; Dana Cristina Bratu Journal: Materials (Basel) Date: 2022-03-15 Impact factor: 3.748