Alcohol-Containing Mouth-Rinses and the Adhesion of Orthodontic Brackets

Objective: Evaluation of the effect of different alcohol containing mouth rinses on the shear bond strength of orthodontic brackets bonded to enamel.

Methods: One hundred and twenty extracted bovine incisor teeth were cleaned with pumice and the buccal enamel surface of each tooth was conditioned for 20 seconds with 37% phosphoric acid gel.  Transbond sealant (3M Unitek. Monrovia, CA) was then applied according to manufacturer's instructions. SPEED® (Strite Industries, Cambridge, Ontario, Canada) and APC II® precoated maxillary central incisor brackets (3M Unitek, Monrovia, CA) were used in the study. The average surface area of the bracket bases were 7.41 mm² and 9.81 mm² respectively. Teeth were stored for 24 hours at 37 ºC and 100% relative humidity.  Teeth from each bracket group were randomly assigned into 4 subgroups:  Water (Control); Mouth rinse containing no ethanol (Breathe RX, Discus Dental, Culver City, CA); Mouth rinse containing 15% ethanol (Scope, Proctor and Gamble Cincinnati, OH); Mouth rinse containing 26.9% ethanol (Listerine, Warner-Lambert Consumer Healthcare, Morris plains, NJ)

Teeth were cycled at 37 ºC for 730 cycles [simulating a twice-daily rinse for one year] in each mouth rinse with a 30 second dwell time. Shear bond strength was performed at a crosshead speed of 5mm/min. 

Results: Mean (Standard Deviation) and results of ANOVA and Tukey's HSD tests at alpha = 0.05 are presented in Table.

Mouth Rinse	Speed Bracket	Victory APC II
Water	6.58 (5.54) a	6.99 (2.53) a
Breathe RX (no ethanol)	2.75 (0.96) b	3.89 (1.68) ab
Scope (15% ethanol)	3.84 (2.13) ab	4.63 (1.62) ab
Listerine (26.9% ethanol)	5.36 (3.44) ab	6.57 (1.90) a
F-ratio & p- Value	F= 4.49       p < 0.001

Groups with the same letter are not significantly different

Conclusions: The statistical results did not demonstrate a direct relationship between alcohol  content/concentration and the shear bond strength of the adhesive to bovine enamel.