| 0577 Fracture strength of Class II restorations using the ART approach | ||
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T.J.E. BARATA, E. BRESCIANI, D.F.G. CEFALY, J.R.P. LAURIS, and M.F.L. NAVARRO, University of São Paulo, Bauru Dental School, Bauru, Brazil Objectives: To evaluate the influence of three variables on the fracture strength of glass ionomer Class II restorations, using the ART approach: (1) the glass ionomer cement Ketac-Molar(KM)- 3M ESPE, Fuji VIII(F8)- GC and Rely X(RX)- 3M ESPE, (2) the presence (PR) or absence (AR) of retentive grooves and (3) the insertion method, with injector syringe (IS) or with a spoon excavator (SE). Methods: One hundred and twenty noncarious human maxillary premolars were divided into 12 groups: group 1: KM(PR+IS), group 2: KM(PR+SE), group 3: KM(AR+IS), group 4: KM(AR+SE), group 5: F8(PR+IS), group 6: F8(PR+SE), group 7: F8(AR+IS), group 8: F8(AR+SE), group 9: RX(PR+IS), group 10: RX(PR+SE), group 11: RX(AR+IS), group 12: RX(AR+SE). Class II preparations were standardized using a modified microscope device. Teeth were restored and stored at 37o C, 100% of humidity for 24 h in a stove. Teeth were submitted to the compressive axial loading in a testing machine - EMIC, at 0.5 mm/min of speed, until the breakdown of the restorations. Three way ANOVA and Tukey tests were performed. Results: Mean values plus standard deviations, in Kgf, were: group 1: 65.66±0.245, group 2: 62.58±0.241, group 3: 57.11±0.196, group 4: 51.94±0.231, group 5: 63.05±0.217, group 6: 60.120±0.239, group 7: 55.11±0.196, group 8: 49.20±0.163, group 9: 50.99±0.246, group 10: 48.810±0.255, group 11: 45.53±0.266, group 12: 41.88±0.304. ANOVA (p<0.001) and Tukey tests showed a statistically significant mutual influence among all tested variables: material x retention; material x insertion; retention x insertion and material x retention x insertion. Conclusion: As far as fracture strength Ketac-Molar, retentive grooves and injector syringe presented the best performance. Regardless the glass ionomer cement used in all tested groups, the presence of retentions and the insertion with a syringe increased the fracture strength values. Supported by CNPq and Bauru Dental School-University of São Paulo, Brazil. | ||
| Seq #78 - Composition, Physical Properties, and Fatigue 10:15 AM-11:30 AM, Thursday, 11 March 2004 Hawaii Convention Center Exhibit Hall 1-2 | ||
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Back to the Dental Materials: VI - Polymer Materials-Mechanical Properties and Degradation Program
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