Assessment of bracket placement and bond strength when comparing direct bonding to indirect bonding techniques

A clinical evaluation was made to determine the advantages and disadvantages of two currently used techniques for bonding brackets to teeth of orthodontic patients. The two techniques were compared with respect to (1) bracket placement, (2) bond strength, (3) rate of failure, and (4) clinical and laboratory time involved in the two procedures. Vertical bracket placement showed no statistically significant differences. The only exceptions were the maxillary canines, where the indirect technique yielded better results (P less than 0.05), and the mandibular second premolars where the direct-bonded brackets were placed closer to ideal (P less than 0.01). Angular bracket placement showed statistically significant differences on the maxillary (P less than 0.01) and mandibular (P less than 0.05) canines, with the indirect bonds being more accurate. The bond strength results indicated great variability from one patient to another. The bracket failures, recorded 3 months after appliance placement, were 4.5 percent for the indirect technique and 5.3 percent for the direct technique. Average time needed for completion of the direct bonding technique was 42.18 minutes. The indirect technique and laboratory procedures required 53.73 minutes, of which 23.91 minutes represented actual clinical time.