title: Effects of Different Surface Treatments on Composite Repairs.
abstract: OBJECTIVE
  To evaluate the influence of different surface treatments on roughness and bond strength of composite repairs.
  
  
  METHODS
  120 truncated conical specimens were prepared with composite Grandio SO (VOCO) and submitted to 5000 thermal cycles. Specimens were divided into 12 groups (n = 10) regarding the surface treatments: negative control (NC), without treatment; medium-grit diamond bur (MGD); coarse-grit diamond bur (CGD); conventional carbide bur (ConC); crosscut carbide bur (CutC); chemical vapor deposition diamond bur (CVD); sandblasting with aluminum oxide (AlO); Er:YAG laser 200 mJ/10 Hz (Er200); Er:YAG laser 60 mJ/10 Hz (Er50); Nd:YAG laser 120 mJ/15 Hz (Nd120); Nd:YAG laser 60 mJ/ 15Hz (Nd60); air abrasion with 110-μm silica modified aluminum oxide (Rocatec Plus-3M) (SIL). After the surface treatments, the surface roughness (Ra) was measured using a profilometer, and then the adhesive system Admira Bond (VOCO) was applied. Another truncated conical restoration was built up with the same composite over the bonded area of each specimen. In order to evaluate the cohesive strength, double-cone specimens were made and considered as a control group (CoheC). The specimens were submitted to tensile bond strength testing and the obtained data (MPa) were evaluated by one-way ANOVA, Tukey's and correlation tests.
  
  
  RESULTS
  ANOVA showed significant differences among experimental groups for roughness and adhesive strength (p < 0.00). The roughness values (Ra) were: NC (0.21 ± 0.19)(c); ConC (0.30 ± 0.08)(c); CutC (0.50 ± 0.22)(cd); CVD (0.74 ± 0.14)(bd); MGD (0.89 ± 0.39)(ab); Er50 (0.89 ± 0.14)(ab); AlO (0.90 ± 0.07)(ab); Nd60 (0.94 ± 0.33ab; SIL (0.98 ± 0.07)(ab); Nd120 (1.10 ± 0.19)(a); CGD (1.10 ± 0.32)(a); Er200 (1.12 ± 0.21)(a). The results of the tensile bond strength test in MPa were: CGD (11.58 ± 3.03)(a); MGD (12.66 ± 3.82)(ab); NC (13.51 ± 3.95(ab); Nd120 (14.11 ± 5.95)(ab); ConC (14.73 ± 6.12)(ab); Er200 (15.51 ± 1.45)(abc); CVD (15.61 ± 5.00(abc); Er50 (16.44 ± 2.75) (abc); CutC (16.79 ± 2.98)(abc); Nd60 (17.72 ± 2.45)(abcd); AlO (18.33 ± 3.19)(bcd); SIL (21.13 ± 4.48(cd); CoheC (23.50 ± 5.81)(d). The groups followed by the same letters were not statistically significantly different (Tukey's test). No correlation was found between bond strength and roughness (r = 0.007).
  
  
  CONCLUSIONS
  Air abrasion with silica coating (Rocatec) was the only method which resulted in significantly higher bond strength in relation to the negative control group. The increase in laser energy produced a rougher surface, but reduced the bond strength.
authors.forename: Graziela Ribeiro
authors.initials: GR
authors.lastname: Batista
authors.forename: Maria Beatriz Beber
authors.initials: MB
authors.lastname: Kamozaki
authors.forename: Natália Cortez
authors.initials: NC
authors.lastname: Gutierrez
authors.forename: Taciana Marco Ferraz
authors.initials: TM
authors.lastname: Caneppele
authors.forename: Carlos
authors.initials: C
authors.lastname: Rocha Gomes Torres
mesh_terms: D020906:Air Abrasion, Dental / Q000379:methods; D000537:Aluminum Oxide / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D018130:Diamond / Q000737:chemistry; D006801:Humans; D053844:Lasers, Solid-State; D008422:Materials Testing; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C509998:Grandio; C479085:admira bond; D002244:Carbon; D012822:Silicon Dioxide; D018130:Diamond; D000537:Aluminum Oxide