One hundred twenty-four metal and seventy-three plastic brackets were bonded with an ultraviolet-sensitive adhesive system to all available teeth width the exception of maxillary first molars, which were banded, of ten orthodontic patients. Following approximately 7 months of orthodontic treatment, the relative adhesion of metal and plastic brackets in maxillary and mandibular arches and on anterior and posterior teeth was clinically and statistically evaluated. Metal brackets bonded in both maxillary and mandibular arches maintained a 95 per cent success rate, while plastic brackets bonded in the maxillary arch exhibited an 89 per cent success rate during the 7-month treatment period. The direct bonding system and brackets utilized in this clinical study can be confidently used in conjunction with banded orthodontic appliances to obtain the maximum in benefits from both banding and direct bonding. It is recommended that bands be placed on maxillary and mandibular molars and on any other teeth located posteriorly in the dental arch where isolation during bonding may be difficult. Plastic brackets should be confined to maxillary anterior teeth to minimize wing breakage. Torque requirements with plastic brackets may be effected with torquing auxilliaries off round arch wires.