title: Influence of ozone application on the repair strength of silorane-based and ormocer-based composites.
abstract: OBJECTIVE
  To evaluate the effect of gasiform ozone on the repair strength of ormocer-based and silorane-based composites.
  
  
  METHODS
  160 cavities were created in methacrylate cylinders. Half of the cavities were filled with a silorane-based composite, whereas the other half was filled with an ormocer-based composite. After storage (1 week, deionized water, 37 degrees C) the specimens of each restorative material were divided into two main experimental groups: in Group 1 the specimens were subjected to a 60-second ozone gas application; in Group 2 no pretreatment was performed (control). The corresponding adhesive of each restorative material was applied as the intermediate repair agent in both groups. Repair cylinders were then built up with the homologous material. Half of the specimens in each group were subjected to thermocycling (5,000 cycles, 5 degrees C-55 degrees C, dwell time 30 seconds, transfer time 5 seconds) prior to testing, whereas the other specimens were immediately tested. The repair strength was assessed with a shear test. The two-way ANOVA with pretreatment and thermocycling as the main factors was used to analyze the shear bond strength data within each restorative material.
  
  
  RESULTS
  The pretreatment, the thermocycling and their interaction did not significantly affect the repair strength of either tested materials (P > 0.05). The ozone treatment did not significantly affect the repair strength. The silorane-based composite showed lower repair strengths compared to those of the ormocer-based composite. The immediate repair strengths in the ozone-treated and control groups were respectively, 28.1 (13.8) MPa and 28.8 (8.8) MPa for the silorane-based composite and 31.5 (9.3) MPa and 35.6 (10.6) MPa for the ormocer-based composite. After thermocycling, the repair strengths in the ozone-treated and control groups were 27.7 (9.7) MPa and 29.5 (11.1 ) MPa for the silorane-based composite and 31.4 (6.0) MPa and 34.2 (4.5) MPa for the ormocer-based composite. Mixed failures occurred most frequently in all experimental groups. In conclusion, ozone did not affect the repair strength of the tested silorane-based and ormocer-based composites.
authors.affiliation: University of Siena, School of Dental Medicine, Department of Fixed Prosthodontics and Dental Materials, Policlinico "Le Scotte", Viale Bracci, Siena, 53100, Italy. elisamagni@hotmail.com
authors.forename: Elisa
authors.initials: E
authors.lastname: Magni
authors.forename: Marco
authors.initials: M
authors.lastname: Ferrari
authors.forename: Federica
authors.initials: F
authors.lastname: Papacchini
authors.forename: Reinhard
authors.initials: R
authors.lastname: Hickel
authors.forename: Nicoleta
authors.initials: N
authors.lastname: Ilie
mesh_terms: D000704:Analysis of Variance; D002516:Ceramics; D003188:Composite Resins / Q000737:chemistry*; D019551:Dental Disinfectants; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents; D008422:Materials Testing; D063225:Organically Modified Ceramics; D010126:Ozone; D033081:Shear Strength; D012821:Silanes; D062047:Silorane Resins
chemical_list: D003188:Composite Resins; D019551:Dental Disinfectants; D017220:Dentin-Bonding Agents; C543062:Filtek LS Low Shrink resin; D063225:Organically Modified Ceramics; D012821:Silanes; D062047:Silorane Resins; D010126:Ozone