Effects of surface treatment and artificial aging on the shear bond strength of orthodontic brackets bonded to four different provisional restorations.
OBJECTIVE
To evaluate the combined effects of material type, surface treatment, and thermocycling on the bond strength of orthodontic brackets to materials used for the fabrication of provisional crowns.


METHODS
Four materials were included in this study (ProTemp, Trim Plus, Trim II, and Superpont C+B). Sixty cylindrical specimens (1 × 3 cm) were prepared from each material and equally divided into three groups. The first group was ground with silica carbide paper, the second was polished with pumice, and the last group was sandblasted with 50-µm aluminum oxide particles. Stainless-steel maxillary central incisor brackets (Victory Series, 3M) were bonded to the provisional material specimens with Transbond XT light-cured composite resin, and half of the specimens from each group were thermocycled 500 times in 5°C and 55°C water baths. Then the brackets were debonded with shear testing, and the results were statistically analyzed by three-way analysis of variance and Tukey's multiple-comparison tests at α  =  0.05. Adhesive Remnant Index (ARI) was also identified.


RESULTS
Before and after thermocycling, ProTemp materials showed the highest shear bond strength with orthodontic brackets (10.3 and 13.1 MPa, respectively). The statistical analysis indicated an interaction among the three independent variables (P < .05) and statistically significant differences in bond strength among provisional materials (P < .001), surface treatments (P < .001), and thermocycling (P < .05). According to the ARI, most groups demonstrated adhesive failure.


CONCLUSIONS
The provisional material type, surface treatment, and artificial aging have a significant effect on bond strength. Sandblasting treatment exerts a beneficial effect on shear bond strength.
a  Director, Dental Biomaterials Research and Development Chair and Associate Professor, Prosthetic Dental Sciences Department, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
Youssef S
YS
Al Jabbari
Sara M
SM
Al Taweel
Mohammed
M
Al Rifaiy
Mohammed Q
MQ
Alqahtani
Theodoros
T
Koutsoukis
Spiros
S
Zinelis
D000180:Acrylic Resins / Q000737:chemistry; D000537:Aluminum Oxide / Q000737:chemistry; D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing / Q000379:methods; D003794:Dental Restoration, Temporary; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D008422:Materials Testing; D016910:Orthodontic Brackets; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D017640:Silicates / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
D000180:Acrylic Resins; D017554:Carbon Compounds, Inorganic; D003188:Composite Resins; D003764:Dental Materials; D011109:Polymethacrylic Acids; D019279:Resin Cements; D017640:Silicates; D017655:Silicon Compounds; C477790:Transbond XT; D014867:Water; D013193:Stainless Steel; C091347:vinyl ethyl methacrylate; C042402:superpont C+B; C069714:Protemp; D000537:Aluminum Oxide; C005144:pumice; C022088:silicon carbide
Adhesives; Orthodontic brackets; Provisional materials; Shear bond strength; Thermocycling