Immediate and six-month space changes after premature loss of a primary maxillary first molar

Background. Premature loss of primary maxillary first molars has been associated with a number of consequences (such as tipping of the first permanent molar). The aim of the authors' study was to investigate dental-arch space problems arising as a result of premature loss of a primary maxillary first molar. Methods. This study was composed of 19 children who experienced unilateral premature loss of a primary maxillary first molar. The authors used each patient's intact contralateral arch segment as a control. The authors obtained maxillary dental study casts two or three days after the tooth was extracted, as well as six months later. Results. The D + E space from the extraction side six months after removal of the tooth (mean ± standard deviation, 15.62 ± 1.13 millimeters) was significantly smaller than the space on the control side (16.88 ± 1.12 mm) and the initial D + E space (16.70 ± 0.69 mm). The authors found a significantly shorter arch length (25.47 ± 1.58 mm) and larger intercanine width (31.29 ± 2.49 mm) six months after the tooth was extracted compared with the initial arch length (25.66 ± 1.64 mm) and intercanine width (30.42 ± 2.64 mm). Conclusions. The early space changes to the maxillary arch subsequent to premature loss of a primary maxillary first molar are primarily distal drift of the primary canines toward the extraction space and palatal migration of the maxillary incisors. Although 1 mm of space was lost, which is statistically significant, this is not likely to be of sufficient clinical significance to warrant use of a space maintainer. If palatal movement appears to be needed, the dentist should consider use of a palatal arch rather than a band-and-loop maintainer. Clinical Implications. The effects of space maintainers need to be re-evaluated in cases of unilateral premature loss of a primary maxillary first molar.