A posttreatment evaluation of direct bonding in orthodontics.

A long-term evaluation was made of results achieved in direct bonding of metal attachments with a chemically polymerized composite material. A total of 705 attachments were bonded to different teeth, including premolars and molars, in forty-six children. Slim bracket bases, small quantities of adhesive paste, and trimming of the excess material were used to improve esthetics and to benefit in respect of gingival condition. The same person bonded all brackets and performed the orthodontic treatment by a friction-free edgewise light-wire technique. Mean treatment time was 17 months. The clinical appearance before, during, and after treatment is shown in Figs. 3 to 5. The failure rates for the whole treatment period were 4 to 10 per cent for central and lateral incisors, canines, and first premolars in both dental arches. The second premolars, which were often in various stages of eruption at the time of bonding, and the molars had higher failure rates (Table I). An evident individual variation was noted, as a few children had a high number of loose brackets. Clinical and scanning electron microscopic studies of tooth surfaces following removal of the brackets demonstrated normal surface appearance when plain-cut tungsten carbide burs rotated at low speed were used to remove remnants of adhesive that could not easily be scraped off. Precoating etched enamel with sealant, in combination with daily fluoride mouth rinses and good oral hygiene, virtually eliminated the caries problem, but regular inspection for interproximal cavities was needed. There were no signs of enamel damage or discoloration for periods of up to 12 months subsequent to bracket removal. Further details of the technical operative procedure, failure analysis, bracket type and design, gingival health, and other aspects of direct bonding were also discussed.