An assessment of root stage of canine and premolar teeth at alveolar eruption.

OBJECTIVE: The primary aim was to evaluate the degree of root development of permanent canines at the time of alveolar eruption. We also aimed to assess whether differences in the degree of root development at alveolar eruption exist between permanent canines and premolars and between maxilla and mandible. DESIGN: A cross-sectional study. SETTING: Barts and The London School of Medicine and Dentistry, Queen Mary University of London. PARTICIPANTS: Two hundred dental panoramic radiographs taken as part of routine dental care. METHODS: Radiographs were assessed for canine and premolar root development stage and eruption level with calibration and repeat measurements undertaken. RESULTS: Two hundred and sixty teeth were identified as being at the level of alveolar eruption. The majority of maxillary canines reached alveolar eruption when root formation was complete. Most premolars and mandibular canines reached alveolar eruption when roots were three-quarters developed. At alveolar eruption, canines were statistically more mature than premolars (p<0.001) and maxillary teeth were more mature than mandibular teeth (p<0.05). CONCLUSIONS: Root development appears to be particularly advanced for maxillary permanent canines, being essentially root-complete at alveolar eruption, while premolars and mandibular permanent canines appear to have three-quarters root development at this stage. This information may be used to inform whether and when to extract primary teeth for orthodontic reasons.