The second molar dilemma in orthodontics: to bond or not to bond?

Objectives: To compare orthodontic treatment (OT) outcome in adolescents undergoing nonextraction fixed OT with or without bonding of second molars using the score of the American Board of Orthodontics Cast Radiograph Evaluation (C-R-Eval).

Materials and methods: This study included healthy adolescents with skeletal Class I or mild Class II/Class III malocclusion, normal or deep overbite (OB), and mild-to-moderate dental crowding (<5 mm) who underwent nonextraction fixed OT with ("bonded" group) or without ("not-bonded" group) bonding of second molars. Patient treatment records, pre- and posttreatment digital models, lateral cephalograms, and orthopantomograms were assessed. The evaluated outcomes included leveling of the curve of Spee (COS), OB, control of incisor mandibular plane angle (IMPA), number of emergency visits (related to poking wires and/or bracket failure of the terminal molar tubes), treatment duration, and C-R-Eval. Treatment variables were compared across time points and among groups.

Results: The sample included 30 patients (mean age 16.07 ± 1.80 years) in the bonded group and 32 patients (mean age 15.69 ± 1.86 years) in the not-bonded group. The mean overall C-R-Eval score was significantly higher (P < .001) in the not-bonded group (25.25 ± 3.98) than in the bonded group (17.70 ± 2.97). There were no significant differences in mean changes of COS, OB, IMPA, or treatment duration among groups. The mean number of emergency visits was significantly higher in the bonded (3.3 ± 0.6) than the not-bonded group (1.9 ± 0.4) (P < .001).

Conclusions: Bonding of second molars enhances the outcome of nonextraction fixed OT as demonstrated by the C-R-Eval without increasing treatment duration, irrespective of more emergency visits.