Effects on Tensile Bond Strength of Brackets after TiF4 Application

Objectives: To analyze the influence of prophylactic treatment with titanium tetrafluoride (TiF4) on surface enamel morphology and on shear bond strength of orthodontic brackets was the objective of this work. Methods: Fifty-four human premolars extracted for orthodontic reasons were divided into: TiF4 group, treated with 1% TiF4 for 1 minute; TiF4+prophylaxis group, treated with 1% TiF4 followed by prophylaxis with fluoride free pumice in a rubber cup; Control group, without fluoride treatment. The bonding procedure was similar in the three groups and samples were submitted to mechanical test after 7 days. For scanning electron microscopy, 12 human extracted premolars were cut in two halves and divided into: Group A, no superficial treatment; Group B, 37% phosphoric acid for 15 seconds; Group C, 1% TiF4 for 1 minute; Group D, 1% TiF4 followed by 37% phosphoric acid; Group E, 1% TiF4 followed by prophylaxis with fluoride free pumice in a rubber cup; Group F, 1% TiF4 followed by prophylaxis and followed by 37% phosphoric acid. Results: The values of bond strength were 6.73 MPa (TiF4), 19.43 MPa (TiF4+Prophylaxis), 17.46 MPa(Comtrol). After the application of 1% TiF4 the morphological appearance revealed a surface layer on all samples.This coating appeared to be retained after etching. TiF4+Prophylaxis did not appear to contribute any obvious physical change on the enamel surface and acid etching produced a roughness surface. Conclusion: The 1% TiF4 application had a negative effect on enamel acid etching and significantly reduced the shear bond strength of adhesive to enamel. After 1% titanium tetrafluoride application followed by prophylaxis the acid resistant glaze was not apparent and acid etching was possible, allowing bonding of orthodontic brackets.