Method: Two orthodontic adhesive systems were evaluated: (1) Orthomite LC which contains phosphoric acid monomer in bonding paste (phosphoric acid/bonding paste system, Sun Medical Co., Ltd.); (2) TransBondTM XT (phosphoric acid/primer/bonding paste system, 3M Unitek). Unground enamel of extracted human premolar was treated according to manufacture’s instructions. For evaluation, stainless steel brackets were bonded to enamel surface under ambient condition (temperature: 23 °C, relative humidity: 50±5 %) or humid condition (temperature: 37 °C, relative humidity: ≥ 95%) prior to being stored in dH2O at 37ºC for 24 hours. All specimens were subjected to SBS test at a cross-head speed of 1.0mm/min. Data were analyzed using one-way ANOVA and Tukey’s test.
Result: With regard to SBS, the highest mean value was found in Orthomite LC under humid condition, whereas that of TransBondTM XT had the lowest SBS (p<0.05). ARI score after SBS test revealed that all specimens of Orthomite LC showed enamel/adhesive or cohesive failures within the resin, whereas 30% of enamel fracture occurred under both condition with TransBondTM XT.
|
Ambient condition |
Humid condition |
Orthomite LC |
20.2±1.4a |
24.4±3.7b |
TransBondTM XT |
19.5±2.4a |
14.7±0.9c |
Values with same letters are not significantly different (p>0.05).
Conclusion: These findings indicate that SBS of Orthomite LC was comparable to or better than that of TransBondTM XT and enamel fracture was not observed in the case of Orthomite LC. It is concluded that Orthomite LC is an useful orthodontic adhesive system for clinical use.