Bonding Customized Lingual Appliance with a New Indirect Bonding Tray

Objective: To evaluate the performance of a new indirect bonding tray and four adhesives in bonding customized lingual appliance.

Methods: To simulate bonding to patients in a clinic, bovine arches were prepared by planting bovine teeth in plaster material in a mold.  Digital scans of the arches were taken (GOM) to manufacture customized lingual appliances and a transfer tray.  The customized lingual appliances were manufactured similarly to Incognito Appliance (3M Unitek) except that the base of the gold bracket was sandblasted only and did not have a custom resin base.  A new indirect bonding tray (3M Unitek) was manufactured utilizing digital bracket positioning method.  Using the tray, each arch was bonded with a different adhesive.  The adhesives included a dual-cure adhesive, RelyX Unicem 2 Automix (RXU, 3M ESPE) and three chemical-cure adhesives, Transbond IDB (TBIDB, 3M Unitek), Sondhi Rapid Set (SD, 3M Unitek) and Maximum Cure (MC, Reliance).  After bonding to the bovine arch, chemical-cure adhesives were allowed to set, and light cure was performed on the dual-cure adhesive.  The tray was then removed.  The bonded bovine arches (Fig.1) were stored in water for 17 days.  Individual bonded bovine teeth were separated from the plaster arch and mounted in acrylic for bond strength test in a shear-peel mode using MTS Universal Test Machine.

Results: The mean bond strengths of 4 arches bonded with different adhesives were all greater than 15 lb (Fig.2) and not statistically different (p-value=0.132).  When adjusted for area bonded, RXU showed statistically higher bond strength than the others (Fig.3, RXU>TBIDB=SD=MC, p-value=0.001).  All teeth did not show enamel damage after bonding and debonding tests.

Conclusion: Adequate bonding performance was achieved with a new indirect bonding tray and 4 adhesives.  A custom resin base was not required to attain sufficient bond strength with Incognito custom lingual braces.