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Fracture strength of CAD/CAM posterior ceramic crowns after manual enhancement of occlusal morphology.
Int J Comput Dent. 2018; 21(3):191-200.IJ

Abstract

PURPOSE

The aim of this study was to investigate the fracture strength of computer-aided design/computer-aided manufacturing (CAD/CAM) posterior ceramic crowns with and without post-milling manual enhancement of occlusal morphology (MEOM), as indicated especially with early CAD/CAM restorations that have limited capacity to generate natural occlusal morphology.

MATERIALS AND METHODS

A mandibular molar of an acrylic tooth model was prepared to receive a CAD/CAM all-ceramic crown and was used as a master die to fabricate 80 prepared tooth replicas using an epoxy resin with an elastic modulus (E) of 18 GPa. The crown was designed using Cerec software's Biogeneric Copy Design mode (Sirona). Eighty identical monolithic crowns were fabricated by milling four types of ceramic blocks. Forty monolithic crowns (10 of each ceramic system) were randomly selected as the control group, and MEOM was performed for each of the other 40 crowns by a certified dental technician. Restorations were crystallized and glazed according to the manufacturers' instructions and firing protocols. All crowns were cemented to their respective die using resin cement, and loaded to fracture at a crosshead speed of 0.5 mm/min. The resultant fractures were classified into three modes. Data were statistically analyzed using the nonparametric Mann-Whitney U test at α = 0.05.

RESULTS

The MEOM treatment decreased the fracture load for all ceramic brands.

CONCLUSION

The MEOM procedure should be considered detrimental for monolithic CAD/CAM-generated crowns and should thus be avoided.

Authors

Passos L
No affiliation info available
Torrealba Y
No affiliation info available
Linke B
No affiliation info available
Street A
No affiliation info available
Passos S
No affiliation info available

MeSH

CeramicsComputer-Aided DesignCrownsDental Prosthesis DesignDental Restoration FailureDental Stress AnalysisHumansMaterials Testing

Pub Type(s)

Journal Article

Language

eng

PubMed ID

30264048

Citation

Passos, Leandro, et al. "Fracture Strength of CAD/CAM Posterior Ceramic Crowns After Manual Enhancement of Occlusal Morphology." International Journal of Computerized Dentistry, vol. 21, no. 3, 2018, pp. 191-200.
Passos L, Torrealba Y, Linke B, et al. Fracture strength of CAD/CAM posterior ceramic crowns after manual enhancement of occlusal morphology. Int J Comput Dent. 2018;21(3):191-200.
Passos, L., Torrealba, Y., Linke, B., Street, A., & Passos, S. (2018). Fracture strength of CAD/CAM posterior ceramic crowns after manual enhancement of occlusal morphology. International Journal of Computerized Dentistry, 21(3), 191-200.
Passos L, et al. Fracture Strength of CAD/CAM Posterior Ceramic Crowns After Manual Enhancement of Occlusal Morphology. Int J Comput Dent. 2018;21(3):191-200. PubMed PMID: 30264048.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Fracture strength of CAD/CAM posterior ceramic crowns after manual enhancement of occlusal morphology. AU - Passos,Leandro, AU - Torrealba,Ysidora, AU - Linke,Bernard, AU - Street,Alexandre, AU - Passos,Sheila, PY - 2018/9/29/entrez PY - 2018/9/29/pubmed PY - 2019/6/25/medline KW - cementation KW - feldspathic ceramic KW - fracture strength KW - leucite-reinforced glass-ceramic KW - lithium disilicate glass-ceramic KW - machinable ceramic KW - monolithic posterior crown KW - occlusal morphology KW - zirconia-reinforced lithium silicate glass-ceramic KW - CAD/CAM SP - 191 EP - 200 JF - International journal of computerized dentistry JO - Int J Comput Dent VL - 21 IS - 3 N2 - PURPOSE: The aim of this study was to investigate the fracture strength of computer-aided design/computer-aided manufacturing (CAD/CAM) posterior ceramic crowns with and without post-milling manual enhancement of occlusal morphology (MEOM), as indicated especially with early CAD/CAM restorations that have limited capacity to generate natural occlusal morphology. MATERIALS AND METHODS: A mandibular molar of an acrylic tooth model was prepared to receive a CAD/CAM all-ceramic crown and was used as a master die to fabricate 80 prepared tooth replicas using an epoxy resin with an elastic modulus (E) of 18 GPa. The crown was designed using Cerec software's Biogeneric Copy Design mode (Sirona). Eighty identical monolithic crowns were fabricated by milling four types of ceramic blocks. Forty monolithic crowns (10 of each ceramic system) were randomly selected as the control group, and MEOM was performed for each of the other 40 crowns by a certified dental technician. Restorations were crystallized and glazed according to the manufacturers' instructions and firing protocols. All crowns were cemented to their respective die using resin cement, and loaded to fracture at a crosshead speed of 0.5 mm/min. The resultant fractures were classified into three modes. Data were statistically analyzed using the nonparametric Mann-Whitney U test at α = 0.05. RESULTS: The MEOM treatment decreased the fracture load for all ceramic brands. CONCLUSION: The MEOM procedure should be considered detrimental for monolithic CAD/CAM-generated crowns and should thus be avoided. SN - 1463-4201 UR - https://www.unboundmedicine.com/medline/citation/30264048/Fracture_strength_of_CAD/CAM_posterior_ceramic_crowns_after_manual_enhancement_of_occlusal_morphology_ DB - PRIME DP - Unbound Medicine ER -