Ectopic Eruption of the Permanent Maxillary First Molar: Predictive Factors for Irreversible Outcome

Purpose: The purpose of this study was to determine the rate of self-correction and predictive factors for irreversible outcome of mesial ectopic eruption of permanent maxillary first molars (EE), in a sample population where no interceptive treatment was initiated. Methods: Charts of patients diagnosed with EE were reviewed, and radiographs were analyzed for predictive factors reported in the literature. Results: Sixty-five EE were included in the study; 46 (71 percent) self-corrected, of which one-third occurred after age nine years. Space loss, with an average of approximately three mm, occurred in 18 EE (28 percent). Increased magnitude of impaction, degree of resorption of the primary second molar, severe lock, and bilateral occurrence were positively correlated with irreversible EE. Multiple regression analysis was positive for increased magnitude of impaction when adjusted for gender and bilateral occurrence. Conclusion: Spontaneous self-correction occurred in 71 percent of permanent maxillary first molars with ectopic eruption; one third of self-corrections occurred after nine years of age. Delaying treatment of ectopic eruption of permanent maxillary first molars may be a viable option when the outcome is uncertain. Increased magnitude of impaction was the most reliable predictor associated with irreversible outcome.