Effect of different bonding agents on prevention of enamel demineralization around orthodontic brackets

Demineralization around the bracket is an undesired side effect of orthodontic treatment. The aim of this in-vitro study was to evaluate the efficacy of 5 bonding agents to prevent enamel demineralization. Two quantification methods were used.

Eighty-five extracted teeth were randomly allocated to 5 groups: (1) Transbond Plus SEP and Transbond XT (both, 3M Unitek, Seefeld, Germany), (2) 37% phosphoric acid, Pro Seal (Reliance Orthodontic Products, Itasca, Ill) and Transbond XT, (3) Clearfil Protect Bond (Kuraray Medical, Okayama, Japan) and Transbond XT, (4) 37% phosphoric acid and Light Bond (Reliance Orthodontic Products), and (5) Ortho Conditioner and Fuji Ortho LC (both, GC, Tokyo, Japan). In-vitro caries was created by pH cycling for 30 days. After demineralization, the teeth were scanned with a commercial cone-beam microtomographic system. Then the teeth were examined by polarized light microscopy.

The 2 methods of examination showed significant differences among the 5 groups according to lesion depth and mineral loss (P < 0.01). The resin-modified glass ionomer cement (group 5) had the lowest values for lesion depth and mineral loss.

Fuji Ortho LC showed a significantly smaller lesion depth and less mineral loss compared with the other materials. The cone-beam microtomographic system is suitable for evaluation of subsurface lesions and has considerable advantages.