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Effect of saliva contamination to shear/peel
bond strength of an orthodontic adhesive
between brackets and tooth surfaces
Authors :
- Eakachai Rerkpitakpanich D.D.S.
- Paiboon Techalertpaisarn D.D.S., Ph.D., Diplomate, Thai Board of Orthodontics
- Supamas Parisanyodom
- Varinee Srimahachota
- Pawarut Duangpatra
Abstract :
Objective To study the effect of saliva contamination on shear/peel bond strength of an orthodontic
adhesive between brackets and tooth surfaces.
Materials and methods Forty five human teeth were divided into 3 groups. Each group consisted of
15 teeth. Tooth surface was treated with pumice and phosphoric acid, then rinsed and blown dry.
Brackets (Standard, 3M Unitex) were bonded to tooth surface with light cure adhesive (Transbond XT,
3M Unitex) under 3 conditions (1 condition for each group) 1) no saliva contamination 2) saliva
contamination after primer application 3) saliva contamination after acid etched, but blown dry before
primer application. The specimens were stored in distilled water at 37°c for 24 hours. Shear/peel bond
strengths were measured by the universal testing machine. The means of bond strength between each
group were compared, using ANOVA while the adhesive remnant index in each group were measured
and tested by the Chi-square at the 95% confidence.
Results Means shear/peel bond strength of groups 1, 2 and 3 were 15.4, 7.1 and 16.9 MPa, respectively.
Those of group 2 were lower than those of group 1 and 3 significantly. Six of 15 brackets in group 2
were bond failure before testing while no failure was found in group 1 and 3. For the non-failure
brackets of group 2, means shear/peel bond strength was 11.9 that was not significantly different to
those of group 1 and 3. The ARI scores of 4 and 5 that indicate less than 10% of adhesive remained on
the tooth surface were found 53.3%, 100% and 73.3% in group 1, 2 and 3, respectively.
Conclusion Saliva contamination after primer application resulted in significantly low bonding strength
and 40% bond failure before testing was found. Shear/peel bond strength in specimens blown dry
before primer application was not different from that of group with no saliva contamination.
(CU Dent J. 2011;34:55-64)
Keywords :
bond strength; bracket; orthodontics; saliva contamination
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