scholarly journals Influence of crown and hybrid abutment ceramic materials on the stress distribution of implant-supported prosthesis

2018 ◽  
Vol 47 (3) ◽  
pp. 149-154 ◽  
Author(s):  
João Paulo Mendes TRIBST ◽  
Amanda Maria de Oliveira DAL PIVA ◽  
Alexandre Luiz Souto BORGES ◽  
Marco Antonio BOTTINO

Abstract Introduction A new dental implant-abutment design is available with the possibility of improving aesthetic with no compromise of mechanical strength, using perforated CAD/CAM ceramic blocks. Objective This study evaluated the influence of crown and hybrid abutment ceramic materials combination on the stress distribution of external hexagon implant supported prosthesis. Method Zirconia, lithium disilicate and hybrid ceramic were evaluated, totaling 9 combinations of crown and mesostructure materials. For finite element analysis, a monolithic crown cemented over a hybrid abutment (mesostructure + titanium base) was modeled and screwed onto an external hexagon implant. Models were then exported in STEP format to analysis software, and the materials were considered isotropic, linear, elastic and homogeneous. An oblique load (30°, 300N) was applied to the central fossa bottom and the system’s fixation occurred on the bone’s base. Result For crown structure, flexible materials concentrate less stress than rigid ones. In analyzing the hybrid abutment, it presented higher stress values when it was made with zirconia combined with a hybrid ceramic crown. The stress distribution was similar regarding all combinations for the fixation screw and implant. Conclusion For external hexagon implant, the higher elastic modulus of the ceramic crowns associated with lower elastic modulus of the hybrid abutment shows a better stress distribution on the set, suggesting a promising mechanical behavior.

2014 ◽  
Vol 1044-1045 ◽  
pp. 100-103
Author(s):  
Zhi Hong Dong ◽  
Chang Chun Zhou

Teeth is the most hard tissue in human body, and its component contains over 96 wt.% inorganic mineral. When the teeth were destroyed by chewing, whiten, etched and friction, etc., ceramic materials are one of the most widely used materials for dental defect repairing or replacement [1-3]. Stress distribution of teeth is necessary to evaluate due to bearing the heavier load, especially the mandibular first molar. But its structure is so complex as not to measure the stress distribution accurately. With the development of CAD/CAM technology, some new technology and equipments occurrence may supply for good methods to evaluate the characteristics of complex structures [4-7]. Since Farah introduced a finite element analysis method into the field of oral medicine in 1973, the method was widely used to research the teeth mechanics, which is most suitable and efficient tools compared with other technologies [8]. In this paper, molar stress distributions were analyzed. By three-dimensional optical scanner and computer 3D design software such as solidworks, Geomagic Studio, CATIA V5, a molar model was built with accuracy and effectiveness, further the mechanical properties of ceramics denture was achieved.


2021 ◽  
Vol 24 (3) ◽  
Author(s):  
Sameh Mahmoud Nabih ◽  
Nady Ibrahim Mohamed Ibrahim ◽  
Ahmed Ramadan Elmanakhly

Objectives: The aim of this study was to analyze mechanical and thermal stresses of hybrid ceramic and lithium disilicate based ceramic of CAD/CAM inlays using 3D Finite element analysis. Material and Methods: A three dimensions finite element model of permanent maxillary premolar designed according to standard anatomy with class II cavity preparation for inlay restored with two different ceramic materials:- 1- Hybrid ceramic (Vita Enamic), 2- Lithium disilicate based ceramic (IPS e.max CAD). Totally six runs were performed on the model as: One loading case for each restorative material was tested in stress analysis; seven points of loading with 140N vertically applied at palatal cusp tip and cusp slop, marginal ridges and central fossa while the models base was fixed as a boundary condition in the two cases. Two thermal analysis cases were performed for each restoration material by applying 5ºC and 55ºC on the crown surface including the restoration surface. Results: The results of all structures were separated from the rest of the model to analyze the magnitude of stress in each component. For each group, maximum stresses on restorative materials, cement, enamel, and dentin were evaluated separately. Both ceramic materials generated similar stress distribution patterns for all groups when a total occlusal load of 140 N was applied. Conclusion: Thermal fluctuations of temperature have a great influence on the stresses induced on both restoration and tooth structure. IPS e.max CAD produced more favorable stresses on the tooth structure than Vita Enamic.   KEYWORDS Ceramics; Finite element analysis; IPS e.max CAD; Lithium disilicate;  Vita Enamic.


2017 ◽  
Vol 88 (2) ◽  
pp. 221-226 ◽  
Author(s):  
S. Kutalmış Buyuk ◽  
Ahmet Serkan Kucukekenci

ABSTRACT Objective: To investigate the shear bond strength (SBS) of orthodontic metal brackets applied to different types of ceramic surfaces treated with different etching procedures and bonding agents. Materials and Methods: Monolithic CAD/CAM ceramic specimens (N = 120; n = 40 each group) of feldspathic ceramic Vita Mark II, resin nanoceramic Lava Ultimate, and hybrid ceramic Vita Enamic were fabricated (14 × 12 × 3 mm). Ceramic specimens were separated into four subgroups (n = 10) according to type of surface treatment and bonding onto the ceramic surface. Within each group, four subgroups were prepared by phosphoric acid, hydrofluoric acid, Transbond XT primer, and Clearfill Ceramic primer. Mandibular central incisor metal brackets were bonded with light-cure composite. The SBS data were analyzed using three-way analysis of variance (ANOVA) and Tukey HSD tests. Results: The highest SBS was found in the Vita Enamic group, which is a hybrid ceramic, etched with hydrofluoric acid and applied Transbond XT Adhesive primer (7.28 ± 2.49 MPa). The lowest SBS was found in the Lava Ultimate group, which is a resin nano-ceramic etched with hydrofluoric acid and applied Clearfill ceramic primer (2.20 ± 1.21 MPa). Conclusions: CAD/CAM material types and bonding procedures affected bond strength (P < .05), but the etching procedure did not (P > .05). The use of Transbond XT as a primer bonding agent resulted in higher SBS.


Author(s):  
R. Adibi-Asl ◽  
Ihab F. Z. Fanous ◽  
R. Seshadri

Elastic modulus adjustment procedures (EMAP) have been employed to determine limit loads of pressure components. On the basis of linear elastic Finite Element Analysis (FEA) with non-hardening elastic properties, i.e., by specifying spatial variations in the elastic modulus, numerous set of statically admissible and kinematically admissible distributions can be generated, and both lower and upper bounds on limit loads can be obtained. Some methods such as the classical, r-node and mα methods provide limit loads on the basis of partly-converged distributions, whereas the accuracy of linear matching procedures rely on fully converged distributions. In this paper, a criterion for establishing the degree of convergence of EMAP is developed, and a simple procedure for achieving improved convergence is described. The procedure is applied to some practical pressure component configurations.


Author(s):  
R. Adibi-Asl

The main objective of this paper is to determine the regions in a component or structure that directly participate in inelastic action (reference volume) using a new robust simplified method, namely the Elastic Modulus Adjustment Procedure (EMAP). The proposed method is based on iterative linear elastic finite element analysis that is implemented by modifying the local elastic modulus of the material at each subsequent iteration. The application of reference volume on optimum shape design is demonstrated through some practical examples including thick-walled cylinder, shank-head component and overlap joint weld. The results show that the reference volume concept can be used to optimize the shape of a body with respect to load carrying capacity and fatigue strength.


2017 ◽  
Vol 5 (2) ◽  
pp. 244-249 ◽  
Author(s):  
Mohamed I. El-Anwar ◽  
Eman A. El-Taftazany ◽  
Hamdy A. Hamed ◽  
Mohamed A. Abd ElHay

AIM: This study aimed to compare the stresses generated by using two or four root form dental implants supporting mandibular overdentures that were retained with ball and locator attachments.METHODS: Under ANSYS environment, four 3D finite element models were prepared. These models simulated complete overdentures supported by two or four implants with either ball or locator attachments as a connection mechanism. The models’ components were created by CAD/CAM package then were imported to ANSYS. Load of 100 N was applied at the right premolar/molar region vertically and at an oblique angle of 110° from lingual direction.RESULTS: Within the conditions of this research, in all cases, it was found that cortical and cancellous bone regions were the least to be stressed. Also, the ball attachment produced higher stresses.CONCLUSION: Caps deformation and stresses are negligible in cases of using locator attachment in comparison to ball attachments. This may indicate longer lifetime and less repair/maintenance operations in implant overdentures retained by locator attachments. Although the study revealed that bone was insensitive to a number of implants or attachment type, it may be recommended to use two implants in the canine region than using four, where the locator attachments were found to be better.


Author(s):  
Numan Aydın ◽  
Serpil Karaoğlanoğlu ◽  
Elif Aybala Oktay ◽  
Bilge Ersöz

Objective: CAD/CAM blocks are widely used in dental restorations around the world. This study aimed to investigate the effects of different polishing and finishing systems on surface roughness and color change of resin-based CAD/CAM blocks. Material and Methods: In this study, material samples of 2×7×12mm were prepared. In three different experimental groups, surface polishing was carried out with one-step, two-step and multi-step polishing systems. The samples in one subgroup of each experimental group were polished with the diamond paste. Once the initial roughness and color values of the samples were measured using a profilometer and a spectrophotometer, the samples were immersed in coffee. Surface roughness and color change (∆E00) results were statistically analyzed using two-way variance analysis (ANOVA). Results: Finishing and polishing systems created significantly different levels of surface roughness on the hybrid ceramic block (Vita Enamic) but not on the composites block (Brilliant Crios, Grandio Blocs). While the two-step and multi-step finishing and polishing systems produced the lowest color change on hybrid ceramic blocks, one-step and two-step systems achieved this on composite blocks (p<0.05). In all test groups, the supplementary polishing performed after regular polishing procedures helped us reduce the surface roughness and color change on CAD/CAM blocks.  Conclusions: The findings obtained in this study suggest that one and two-step polishing systems are more suitable for resin-based composite CAD/CAM blocks; for hybrid ceramic CAD/CAM blocks, on the other hand, two and multi-step finishing and polishing systems seem to be more efficient concerning lower surface roughness and resistance to color changes.


2015 ◽  
Vol 12 (2) ◽  
pp. 53-58 ◽  
Author(s):  
Jonathon S. Egbert ◽  
Andrew C. Johnson ◽  
Daranee Tantbirojn ◽  
Antheunis Versluis

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Elif Yeğin ◽  
Mustafa Hayati Atala

Abstract Background Present study compared the failure load of CAD/CAM-manufactured implant-supported crowns and the stress distribution on the prosthesis-implant-bone complex with different restoration techniques. Methods The materials were divided into four groups: group L-M: lithium disilicate ceramic (LDS, monolithic), group L-V: LDS ceramic (veneering), group ZL-M: zirconia-reinforced lithium silicate ceramic (ZLS, monolithic), group ZL-V: ZLS ceramic (veneering). Crown restorations were subjected to load-to-failure test (0.5 mm/min). Failure loads of each group were statistically analyzed (two-way ANOVA, post hoc Tukey HSD, α = 0.05). Finite element analysis (FEA) was used to compare the stress distribution of crown restorations. Results Group L-M had the highest failure load (2891.88 ± 410.12 N) with a significant difference from other groups (p < 0.05). Although there was a significant difference between group ZL-M (1750.28 ± 314.96 N) and ZL-V (2202.55 ± 503.14 N), there was no significant difference from group L-V in both groups (2077.37 ± 356.59 N) (p > 0.05). Conclusions The veneer application had opposite effects on ceramics, increased the failure load of ZLS and reduced it for LDS without a statistically significant difference. Both materials are suitable for implant-supported crowns. Different restorative materials did not influence the stress distribution, but monolithic restorations reduced the stress concentration on the implant and bone.


2021 ◽  
Vol 11 (2) ◽  
pp. 114-120
Author(s):  
Beyza Ünalan Değirmenci ◽  
Farhad Wahid RASOOL

Aim:  A discoloration existing under the restoration can affect the final restoration color, and various techniques can be used to address this situation. The aim of this study was to investigate the masking ability of the substructure, color of different hybrid CAD/CAM ceramics in various thicknesses. Methodology: A total of 120 samples were produced from 4 different CAD/CAM hybrid ceramic blocks (Cerec blocs, GC Cerasmart, Vita Enamic, 3M Lava Ultimate) in 1, 1.5 and 2 mm thickness. The samples were sliced with 100 N pressure in a low-speed precision cutting device under water cooling. The specimens were placed over the neutral grey background for initial spectrophotometric measurements. A3 color posterior nanohybrid composite (14 X 7 X 1 mm) was preferred to mimic discoloration in the substructure. The cementation procedure of composite and the CAD/CAM hybrid ceramic complex was standardized under 10 N continuous pressure and was performed using a dual cured resin cement. All samples were incubated at 37 °C for 24 hours in incubator after cementation. And the second spectrophotometeric measurement was done via the L*, a*, and b* color attributes of the complex specimens. Additionally, ΔE* values were calculated to determine the color differences between each group. Kruskal Wallis test was used for statistical analysis and Dunn’s test was used for group comparison. Significance was evaluated at least p <0.05. Results: It was found that thickness of the ceramics increases, the substructure color is better masked and the thickness made a statistically significant difference on the masking ability (p<0.01). For 1 mm thick samples, the highest ΔE* value was found in Cerec blocs with 9.36, while the lowest value was found in GC Cerasmart as 4.27. Conclusion: Within the limitations of this study, it was concluded that the tested CAD/CAM hybrid ceramics showed better masking ability than Cerec blocs.   How to cite this article: Ünalan Değirmenci B, Wahid WF. Evaluating the masking ability of CAD/CAM hybrid ceramics with different thicknesses. Int Dent Res 2021;11(2):114-20. https://doi.org/10.5577/intdentres.2021.vol11.no1.9   Linguistic Revision: The English language in this manuscript has been checked by at least two professional editors, both native speakers of English.


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