Spatial changes in the dental arch after premature extraction of the first primary molar – a 12-month observational study

Introduction. Premature loss of the first primary molar may cause malocclusion or impair permanent tooth eruption. Aim. The aim of the study was to assess spatial changes in the dental arch after unilateral premature extraction of the first primary molar. Material and methods. The alginate impressions were taken in patients aged between 5 and 7 years who met the inclusion criteria based on medical history, clinical examination and panoramic x-ray during a preliminary qualifying examination 14 days before or on the day of extraction (before the procedure), as well as during follow up (at months 1, 3, 6 and 12 after extraction). Gypsum models were used to measure the circumference of the arch, the posterior and intercanine width, as well as the interdental distance: IIID-VM, IIID-VD on the side of extraction and the opposite side of the arch. The data were analysed statistically (Statistica 10, Statsoft, p < 0.05). Results. A total of 14 mandibular and 16 maxillary teeth were extracted in 27 children aged between 5 and 7 years (mean age ± SD = 6.64 ± 1.01; 15 boys and 12 girls). A significant loss of interdental spaces for IIID-VM and IIID-VD between the study vs. control side due to distalisation of canine and mesialisation of the second primary molar was observed. Much less significant displacement of these teeth was noted in the case of the presence of the first permanent molar at the time of first primary molar extraction. Conclusions. Premature loss of first primary molars results in reduced interdental distances which does not hinder the eruption of their permanent successors. There is no need for space maintainers.