Effects of modifying the bonding protocol on the shear bond strength of metallic and ceramic orthodontic brackets.
The purpose of this study was to evaluate the in vitro shear bond strength and failure site of metallic and ceramic orthodontic brackets with modified bonding protocols. Sixty bovine mandibular incisors with similar anatomy were selected and divided into six groups (n = 10). In the first protocol, metallic and ceramic brackets were bonded according to the manufacturers' directions (controls); in the second protocol, the step of photocuring with the primer agent was eliminated; and in the third protocol, the primer agent was applied on the tooth and on the bracket base, followed by application of the composite adhesive on the bracket base, with one-step photocure. The same orthodontic adhesive was used for all groups. Shear bond strengths were measured and adhesive remnant index scores (ARI) were determined after bracket failure.  The results demonstrated similar shear bond strengths in the protocols but presented significantly greater values for the metallic groups (two-way ANOVA, P < 0.05). ARI scores were compared with chi-square tests, and the ceramic brackets had significantly greater ARI scores compared to the metallic brackets. Based on these results, the manufacturer's bonding protocol can be modified to save clinical time without compromising adhesion of the brackets.
Department of Orthodontics, Bauru Dental School, University of Sao Paulo, Bauru, Sao Paulo, Brazil.
Thais Maria Friere
TM
Fernandes
Guilherme
G
Janson
Joyce
J
Somensi
Arnaldo
A
Pinzan
Paulo Afonso Silveira
PA
Francisconi
Renata
R
Sathler
Jose Fernando Castanha
JF
Henriques
D000134:Acid Etching, Dental / Q000379:methods; D000268:Adhesiveness; D000818:Animals; D002417:Cattle; D002516:Ceramics / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003743:Dental Enamel / Q000648:ultrastructure; D003799:Dental Stress Analysis / Q000295:instrumentation; D055115:Light-Curing of Dental Adhesives / Q000379:methods; D008422:Materials Testing; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000737:chemistry; D058105:Polymerization; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties
D003188:Composite Resins; D003722:Dental Alloys; D010756:Phosphoric Acids; D019279:Resin Cements; C477790:Transbond XT; D013193:Stainless Steel; C030242:phosphoric acid