Impact of Ceramic Material and Preparation Design on Marginal Fit of Endocrown Restorations.

Background: The aim of this study is to investigate the impact of ceramic material and preparation design on the marginal fit of endocrown restorations. Methods: Forty endocrown restorations were CAD/CAM-fabricated for forty extracted maxillary first premolar teeth. Samples were divided into two groups (n = 20) according to the ceramic materials used: Celtra Duo and Vita Enamic. Each group was divided into two subgroups (n = 10) according to the preparation design: with no intraradicular extension and with 3 mm intraradicular extension. The marginal gap was examined using a digital microscope. Results: Celtra Duo without intraradicular extension recorded the least mean marginal gap (7.74 ± 1.55 µm), while Group Celtra Duo with 3 mm intraradicular extension recorded the highest mean marginal gap (29.54 ± 6.32 µm). Group Vita Enamic recorded a lesser marginal gap (18.03 ± 12.11 µm) than group CD (Celtra Duo) (18.64 ± 12.05 µm). There is a statistically non-significant difference between the two groups of materials (p = 0.873). There is a statistically significant difference between the two tested preparation designs (p < 0.001). Conclusion: All groups recorded a marginal gap within clinically accepted values. Material selection may influence the fitting of restorations. Intraradicular extension for endocrown restorations adversely affects the marginal fit, however, the marginal gap is still within the clinically accepted range.

One-year clinical evaluation of IPS Empress CAD versus polished Celtra Duo ceramic Laminate veneers (randomized controlled clinical trial) / Avaliação clínica de um ano de IPS Empress CAD versus laminados de cerâmica Celtra Duo polidos (ensaio clínico randomizado controlado)

Objective: To evaluate fracture resistance and survival rate of IPS Empress CAD versus Polished Celtra Duo ceramic laminate veneers. Material and Methods:Thirty-six ceramic laminate veneers were fabricated for maxillary anterior teeth. The patients were divided into two groups according to the material Group 1(control group) fabricated from IPS Empress CAD laminate veneers and group 2 (intervention group) fabricated from Polished Celtra Duo laminate veneers. Standardized the same preparation with butt joint design and chamfer finish line located supra gingival were performed for all the teeth. The fabrication of the veneers was performed using Cad\Cam (Ceramill motion) machine, with software (Exocad). The veneers surfaces were treated and silanated according to the manufacture instruction of each ceramic and enamel surfaces were etched where total etch adhesive protocol was obeyed using BISCO. Follow up sessions were done every two months up to one year for each patient using dental probe and operator vision to evaluate the fracture, survival rate, marginal adaptation, sensitivity and caries. according to USPHS criteria (United States Public Health Service). This was performed by an experienced, blinded investigator. Results: Fracture resistance, marginal adaptation, retention, caries and sensitivity were evaluated according to the criteria of USPHS and we found there is no significant difference as both groups scaled zero score. Conclusion: Both IPS Empress Cad and Polished Celtra Duo laminate veneers revealed successful clinical performance in terms of fracture resistance, marginal adaptation, retention, and sensitivity after one year follow up period (AU)

Objetivo: Avaliar a resistência à fratura e a taxa de sobrevivência de laminados de cerâmica IPS Empress CAD versus Celtra Duo polidos. Material e Métodos: Trinta e seis facetas cerâmicas laminadas foram confeccionadas para dentes anteriores superiores. Os pacientes foram divididos em dois grupos de acordo com o material Grupo 1 (grupo controle) confeccionado com laminados IPS Empress CAD e grupo 2 (grupo intervenção) confeccionado com laminados Celtra Duo polidos. A mesma forma de preparo e acabamento de chanfro localizado supra-gengival padronizados foram realizados para todos os dentes. A confecção das facetas foi realizada em máquina Cad \ Cam (Ceramill motion), com software (Exocad). As superfícies laminadas foram tratadas e silanizadas de acordo com as instruções do fabricante de cada cerâmica e as superfícies de esmalte foram condicionadas seguindo o protocolo adesivo de condicionamento ácido total com BISCO. Sessões de acompanhamento foram realizadas a cada dois meses durante um ano para cada paciente usando sonda exploradora e visão do operador para avaliar a fratura, taxa de sobrevivência, adaptação marginal, sensibilidade e cárie; de acordo com os critérios USPHS (Serviço de Saúde Pública dos Estados Unidos). Isso foi realizado por um investigador experiente e cego. Resultados: a resistência à fratura, adaptação marginal, retenção, cárie e sensibilidade foram avaliadas de acordo com os critérios da USPHS e não encontramos diferença significativa, pois ambos os grupos escalonaram pontuação zero. Conclusão: As facetas laminadas IPS Empress Cad e Celtra Duo polido revelaram desempenho clínico bem-sucedido em termos de resistência à fratura, adaptação marginal, retenção e sensibilidade após um período de acompanhamento de um ano. (AU)

Evaluation of zirconia and zirconia-reinforced glass ceramic systems fabricated for minimal invasive preparations using a novel standardization method.

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.

Three-Dimensional Digital Evaluation of the Fit of Endocrowns Fabricated from Different CAD/CAM Materials.

PURPOSE: A wide variety of CAD/CAM materials are available for single-tooth restorations. CAD/CAM material characteristics are different and may influence CAM fabrication accuracy. There is no study investigating the influence of different CAD/CAM materials on the final fit of the restoration. The aim of this study was to evaluate the fit of endocrowns fabricated from different CAD/CAM materials using a new 3D evaluation method with an intraoral scanning system. The null hypothesis was that there are no significant differences for the fitting accuracy of different CAD/CAM materials. MATERIALS AND METHODS: Preparation for an endocrown was performed on a maxillary right first molar on a typodont, and restorations were fabricated with a chairside CAD/CAM system (CEREC Omnicam, MCXL). Three groups using three different CAD/CAM materials were established (each n = 10): zirconia-reinforced lithium silicate ceramic (Celtra Duo; CD), leucite-reinforced silicate ceramic (Empress CAD; EM), resin nanoceramic (Lava Ultimate; LU). A 3D digital measurement technique (OraCheck, Cyfex AG) using an intraoral scanner (CEREC Omnicam) was used to measure the difference in fit between the three materials for a master endocrown preparation. The preparation scan and the endocrown fit scan were matched with special difference analysis software OraCheck. Three areas were selected for fitting accuracy measurements: margin (MA), axial (AX), occlusal (OC). Statistical analysis was performed using 80% percentile, one-way ANOVA, and post-hoc Scheffé test. Significance level was set to p = 0.05. RESULTS: Results varied from best 88.9 ± 7.7 µm for marginal fit of resin nanoceramic restorations (LU_MA) to worst 182.3 ± 24.0 µm for occlusal fit of zirconia-reinforced lithium silicate restorations (CD_OC). Statistically significant differences were found both within and among the test groups. Group CD performed statistically significantly different from group LU for marginal fit (MA) and axial fit (AX) (p < 0.05). For occlusal fit (OC), no statistically significant differences were found within all three test groups (p > 0.05). Deviation pattern for differences was visually analyzed with a color-coded scheme for each restoration. CONCLUSIONS: Statistically significant differences were found for different CAD/CAM materials if the CAM procedure was identical. Within the limitations of this study, the choice of CAD/CAM material may influence the fitting accuracy of CAD/CAM-fabricated restorations.

Influence of material thickness on fractural strength of CAD/CAM fabricated ceramic crowns.

The fracture behavior of CAD/CAM fabricated crowns was investigated as a function of material thickness for six silicate ceramic materials: Mark II, e.max CAD, Celtra Duo milled, Celtra Duo fired, Suprinity, Enamic. Crowns with thicknesses 0.5/1.0/1.5 mm were fabricated with CEREC and adhesively seated to dies fabricated with stereolithography technology (n=144). Thermomechanical loading and fractural loading was performed. Statistical analysis was done with one-way ANOVA and post-hoc Scheffé test. For 1.5 mm, all crowns survived fatigue testing, for 1.0 mm, survival was 100% only for materials e.max CAD and Suprinity. For 0.5 mm, best survival rate was 37.5% for Suprinity. Maximum fractural loading significantly varied among the groups. For 0.5 mm, highest value was found for Suprinity (660.1 N). Mark II showed lowest values for 1.0 mm (482.0 N), and 1.5 mm groups (634.8 N). e.max CAD showed highest values for 1.0 mm (774.2 N), and 1.5 mm groups (1,240.8 N).