Shear Bond Strength of Molar Tubes to Enamel Using an Orthodontic Resin-Modified Glass Ionomer Cement Modified with Amorphous Calcium Phosphate

Abstract

Objectives: This study aimed to assess the shear bond strength (SBS) of molar tubes to the enamel surface of molar teeth using a resin-modified glass ionomer (RMGI) cement modified with amorphous calcium phosphate (ACP).
 Materials and Methods: In this in-vitro study, 60 extracted human third molars were randomly divided into four groups for bonding of molar tubes to the enamel surface. Fuji Ortho LC and Fuji Ortho LC modified with ACP (1.55 wt%) were used in groups 1 and 2, respectively. In group 3, the enamel surface was sandblasted, and bonding was then performed using Fuji Ortho LC glass ionomer modified with ACP. In group 4, molar tubes were conventionally bonded using Transbond XT composite. The SBS was measured using a universal testing machine.
 Results: The mean SBS of groups 1 to 4 was 10.22, 6.88, 9.4, and 13.68 MPa, respectively. Only the SBS of group 1 was not significantly different from that of groups 3 and 4 (P>0.05). Comparison of adhesive remnant index (ARI) scores of the groups revealed significant differences only between groups 1 and 4 (P<0.001) and between groups 1 and 2 (P=0.002).
 Conclusion: The results revealed that the addition of ACP to Fuji Ortho LC significantly decreased the SBS of molar tubes bonded to enamel compared to the conventional resin bonding system. Sandblasting of the enamel surface significantly increased the bond strength. Fuji Ortho LC modified with ACP is recommended for bonding of molar tubes to posterior teeth considering its cariostatic property.

The evaluation of shear bond strength of resin-modified glass ionomer cement with the addition of 45S5 bioactive glass using two conventional methods.

“…Previous research that compared the strength of an orthodontic bracket to enamel surfaces following the use of RMGI and resin composites have reported different results. [26][27] In the present study, the shear bond strength of orthodontic brackets to the enamel surfaces when using the resin composite was slightly higher than that…”

Effect of ageing media on shear bond strength of metal orthodontic brackets bonded with different adhesive systems (A comparative in-vitro study)

“…In both ageing groups, the NFRA had the highest value of mean SBS, while the PLFRA had the least value of mean SBS among the tested adhesives, but above clinically acceptable SBS. This outcome might be based on that the enamel surfaces in this group were conditioned with 37% phosphoric acid instead of the polyacrylic acid conditioner, this would produce rougher enamel surface, and consequently enhanced the bond strength; this explanation was reported by Cacciafesta et al (21) and Tanbakuchi et al (22) Another possible explanation is that the enamel surfaces were adequately wet during the bonding procedure, otherwise the SBS would be adversely affected if the enamel surface was desiccated. (23) The current study demonstrated that there was highly significant difference between the NFRA and PLFRA groups, these observations were congruent with Yassaei et al (24) , who concluded that the Fuji Ortho LC had a significantly reduced SBS values compared to Transbond XT for metal and ceramic brackets.…”