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Optimizing preparation design for metal-free composite resin crowns.
J Prosthet Dent. 2008 Sep; 100(3):211-9.JP

Abstract

STATEMENT OF PROBLEM

Although composite resin materials are used for posterior crown restorations, the influence of preparation design, material thickness, convergence angle, and method of cementation on fracture resistance remains unclear.

PURPOSE

The purpose of this in vitro study was to test the hypothesis that minimal preparation designs provide an acceptable level of fracture resistance for posterior composite resin crowns.

MATERIAL AND METHODS

Nonreinforced Artglass composite resin crowns (n=128) were fabricated on human molars in 16 test groups (n=8). Axial tooth preparation included a 1-mm-deep shoulder or a 0.5-mm chamfer preparation, whereas occlusal reduction was either 0.5 mm or 1.3 mm. The total angle of convergence was 4 or 11 degrees and the crowns were cemented either with glass ionomer cement (Ketac Cem) or resin cement (2bond2). After 10,000 thermal cycles, crowns were vertically loaded until failure occurred; load was measured in newtons. Statistical analysis was performed by a 4-way ANOVA (alpha=.05).

RESULTS

Statistical analysis revealed significant effects of occlusal thickness (P<.001), cement (P<.001), preparation design (P=.011), and convergence angle (P=.001) on the fracture resistance of the composite crowns. For composite resin crowns with an occlusal thickness of 0.5 mm, the resistance to fracture was lower than for crowns with a 1.3-mm thickness. Fracture resistance was greater when resin cement was used, and greater for the chamfer finish line than for the shoulder finish line. Use of a greater total convergence angle reduced fracture resistance.

CONCLUSIONS

Fracture resistance of composite resin crowns was significantly improved by increasing the occlusal thickness of the crowns, by using resin cement, and by reducing the total convergence angle.

Authors+Show Affiliations

Department of Prosthodontics, University of Heidelberg. Heidelberg, Germany. Brigitte_Ohlmann@med.uni-heidelberg.deNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Randomized Controlled Trial

Language

eng

PubMed ID

18762033

Citation

Ohlmann, Brigitte, et al. "Optimizing Preparation Design for Metal-free Composite Resin Crowns." The Journal of Prosthetic Dentistry, vol. 100, no. 3, 2008, pp. 211-9.
Ohlmann B, Gruber R, Eickemeyer G, et al. Optimizing preparation design for metal-free composite resin crowns. J Prosthet Dent. 2008;100(3):211-9.
Ohlmann, B., Gruber, R., Eickemeyer, G., & Rammelsberg, P. (2008). Optimizing preparation design for metal-free composite resin crowns. The Journal of Prosthetic Dentistry, 100(3), 211-9. https://doi.org/10.1016/S0022-3913(08)60180-8
Ohlmann B, et al. Optimizing Preparation Design for Metal-free Composite Resin Crowns. J Prosthet Dent. 2008;100(3):211-9. PubMed PMID: 18762033.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Optimizing preparation design for metal-free composite resin crowns. AU - Ohlmann,Brigitte, AU - Gruber,Rudolf, AU - Eickemeyer,Grit, AU - Rammelsberg,Peter, PY - 2008/9/3/pubmed PY - 2008/12/17/medline PY - 2008/9/3/entrez SP - 211 EP - 9 JF - The Journal of prosthetic dentistry JO - J Prosthet Dent VL - 100 IS - 3 N2 - STATEMENT OF PROBLEM: Although composite resin materials are used for posterior crown restorations, the influence of preparation design, material thickness, convergence angle, and method of cementation on fracture resistance remains unclear. PURPOSE: The purpose of this in vitro study was to test the hypothesis that minimal preparation designs provide an acceptable level of fracture resistance for posterior composite resin crowns. MATERIAL AND METHODS: Nonreinforced Artglass composite resin crowns (n=128) were fabricated on human molars in 16 test groups (n=8). Axial tooth preparation included a 1-mm-deep shoulder or a 0.5-mm chamfer preparation, whereas occlusal reduction was either 0.5 mm or 1.3 mm. The total angle of convergence was 4 or 11 degrees and the crowns were cemented either with glass ionomer cement (Ketac Cem) or resin cement (2bond2). After 10,000 thermal cycles, crowns were vertically loaded until failure occurred; load was measured in newtons. Statistical analysis was performed by a 4-way ANOVA (alpha=.05). RESULTS: Statistical analysis revealed significant effects of occlusal thickness (P<.001), cement (P<.001), preparation design (P=.011), and convergence angle (P=.001) on the fracture resistance of the composite crowns. For composite resin crowns with an occlusal thickness of 0.5 mm, the resistance to fracture was lower than for crowns with a 1.3-mm thickness. Fracture resistance was greater when resin cement was used, and greater for the chamfer finish line than for the shoulder finish line. Use of a greater total convergence angle reduced fracture resistance. CONCLUSIONS: Fracture resistance of composite resin crowns was significantly improved by increasing the occlusal thickness of the crowns, by using resin cement, and by reducing the total convergence angle. SN - 1097-6841 UR - https://www.unboundmedicine.com/medline/citation/18762033/Optimizing_preparation_design_for_metal_free_composite_resin_crowns_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-3913(08)60180-8 DB - PRIME DP - Unbound Medicine ER -