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Fracture Resistance of Various Thickness e.max CAD Lithium Disilicate Crowns Cemented on Different Supporting Substrates: An In Vitro Study.
J Prosthodont. 2019 Dec; 28(9):997-1004.JP

Abstract

PURPOSE

To investigate the influence of abutment material properties on the fracture resistance and failure mode of lithium disilicate (IPS e.max) CAD/CAM (computer-aided design/manufacturing) crowns on traditionally and minimally prepared simulated tooth substrates.

MATERIALS AND METHODS

Thirty lithium disilicate (IPS e.max) CAD/CAM crowns were divided into three groups (n = 10): TD: traditional thickness crowns cemented on Paradigm MZ100 abutments; MD: minimal thickness crowns cemented on Paradigm MZ100 abutments; ME: minimal thickness crowns cemented on e.max abutments. The 3Shape system was used to scan, design and mill all abutments and crowns with a die space set to 40 µm. Traditional thickness crowns were designed based on manufacturer guidelines with 1.5 mm occlusal thickness and 1.0 mm margins. Minimal thickness crowns were designed with 0.7 mm occlusal thickness and 0.5 mm margins. MZ100 composite and e.max abutments were selected to simulate dentin and enamel substrates, respectively, based on their elastic-modulus. Variolink Esthetic was used to cement all samples following manufacturer's instructions. A universal testing machine was used to load all specimens to fracture with a 3 mm radius stainless steel hemispherical tip at a crosshead speed 0.5 mm/minute along the longitudinal axis of the abutment with a 1 mm thermoplastic film placed between the loading tip and crown surface. Data was analyzed using ANOVA and Bonferroni post hoc assessment. Fractographic analysis was performed with scanning electron microscopy (SEM).

RESULTS

The mean fracture load (standard deviation) was 1499 (241) N for TD; 1228 (287) N for MD; and 1377 (96) N for ME. Statistically significant difference between groups did not exist (p = 0.157, F = 1.995). In groups TD and MD with low e-modulus abutments, the dispersion of a probability distribution (coefficient of variation: CV) was statistically higher than that of group ME with high e-modulus abutments. SEM illustrated larger micro-fracture dimensions in Group MD than Group ME.

CONCLUSION

Minimal thickness e.max crowns did not demonstrate statistical difference in fracture resistance from traditional thickness crowns. Fracture mechanisms of minimal thickness e.max crowns may be affected by the e-modulus of the substrate. Minimal thickness e.max crowns may be a viable restorative option when supported by high e-modulus materials.

Authors+Show Affiliations

University of Illinois at Chicago - Restorative Dentistry, Chicago, IL, United States.University of Illinois at Chicago - Restorative Dentistry, Chicago, IL, United States.Department of Stomatology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.University of Illinois at Chicago - Restorative Dentistry, Chicago, IL, United States.University of Illinois at Chicago - Restorative Dentistry, Chicago, IL, United States.University of Illinois at Chicago - Restorative Dentistry, Chicago, IL, United States.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31469479

Citation

Chen, Sara Elizabeth, et al. "Fracture Resistance of Various Thickness E.max CAD Lithium Disilicate Crowns Cemented On Different Supporting Substrates: an in Vitro Study." Journal of Prosthodontics : Official Journal of the American College of Prosthodontists, vol. 28, no. 9, 2019, pp. 997-1004.
Chen SE, Park AC, Wang J, et al. Fracture Resistance of Various Thickness e.max CAD Lithium Disilicate Crowns Cemented on Different Supporting Substrates: An In Vitro Study. J Prosthodont. 2019;28(9):997-1004.
Chen, S. E., Park, A. C., Wang, J., Knoernschild, K. L., Campbell, S., & Yang, B. (2019). Fracture Resistance of Various Thickness e.max CAD Lithium Disilicate Crowns Cemented on Different Supporting Substrates: An In Vitro Study. Journal of Prosthodontics : Official Journal of the American College of Prosthodontists, 28(9), 997-1004. https://doi.org/10.1111/jopr.13108
Chen SE, et al. Fracture Resistance of Various Thickness E.max CAD Lithium Disilicate Crowns Cemented On Different Supporting Substrates: an in Vitro Study. J Prosthodont. 2019;28(9):997-1004. PubMed PMID: 31469479.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Fracture Resistance of Various Thickness e.max CAD Lithium Disilicate Crowns Cemented on Different Supporting Substrates: An In Vitro Study. AU - Chen,Sara Elizabeth, AU - Park,Albert Christopher, AU - Wang,Jingxu, AU - Knoernschild,Kent L, AU - Campbell,Stephen, AU - Yang,Bin, Y1 - 2019/10/10/ PY - 2019/08/07/accepted PY - 2019/8/31/pubmed PY - 2019/12/18/medline PY - 2019/8/31/entrez KW - Monolithic KW - all ceramic crown KW - load-bearing capacity KW - occlusal thickness KW - preparation design KW - ultra-thin crown SP - 997 EP - 1004 JF - Journal of prosthodontics : official journal of the American College of Prosthodontists JO - J Prosthodont VL - 28 IS - 9 N2 - PURPOSE: To investigate the influence of abutment material properties on the fracture resistance and failure mode of lithium disilicate (IPS e.max) CAD/CAM (computer-aided design/manufacturing) crowns on traditionally and minimally prepared simulated tooth substrates. MATERIALS AND METHODS: Thirty lithium disilicate (IPS e.max) CAD/CAM crowns were divided into three groups (n = 10): TD: traditional thickness crowns cemented on Paradigm MZ100 abutments; MD: minimal thickness crowns cemented on Paradigm MZ100 abutments; ME: minimal thickness crowns cemented on e.max abutments. The 3Shape system was used to scan, design and mill all abutments and crowns with a die space set to 40 µm. Traditional thickness crowns were designed based on manufacturer guidelines with 1.5 mm occlusal thickness and 1.0 mm margins. Minimal thickness crowns were designed with 0.7 mm occlusal thickness and 0.5 mm margins. MZ100 composite and e.max abutments were selected to simulate dentin and enamel substrates, respectively, based on their elastic-modulus. Variolink Esthetic was used to cement all samples following manufacturer's instructions. A universal testing machine was used to load all specimens to fracture with a 3 mm radius stainless steel hemispherical tip at a crosshead speed 0.5 mm/minute along the longitudinal axis of the abutment with a 1 mm thermoplastic film placed between the loading tip and crown surface. Data was analyzed using ANOVA and Bonferroni post hoc assessment. Fractographic analysis was performed with scanning electron microscopy (SEM). RESULTS: The mean fracture load (standard deviation) was 1499 (241) N for TD; 1228 (287) N for MD; and 1377 (96) N for ME. Statistically significant difference between groups did not exist (p = 0.157, F = 1.995). In groups TD and MD with low e-modulus abutments, the dispersion of a probability distribution (coefficient of variation: CV) was statistically higher than that of group ME with high e-modulus abutments. SEM illustrated larger micro-fracture dimensions in Group MD than Group ME. CONCLUSION: Minimal thickness e.max crowns did not demonstrate statistical difference in fracture resistance from traditional thickness crowns. Fracture mechanisms of minimal thickness e.max crowns may be affected by the e-modulus of the substrate. Minimal thickness e.max crowns may be a viable restorative option when supported by high e-modulus materials. SN - 1532-849X UR - https://www.unboundmedicine.com/medline/citation/31469479/Fracture_Resistance_of_Various_Thickness_e_max_CAD_Lithium_Disilicate_Crowns_Cemented_on_Different_Supporting_Substrates:_An_In_Vitro_Study_ L2 - https://doi.org/10.1111/jopr.13108 DB - PRIME DP - Unbound Medicine ER -