Interpretations
buccally displaced canines [, tooth
ERUPTION
An interesting finding was that the total maxillary dental arch length was achieved earlier, the length extension persisted better in the long term, and more space was gained in EG compared with LG (The eruption stage of the maxillary second molars reduces distal movement of the maxillary first molars [This study showed that the intermolar width in the maxillary dental arch was stable, and the outcome was reached earlier in EG compared with LG. Studies on normal occlusion have demonstrated the long-term stability of dental arch widths after adolescence [Dental crowding and reduced intercanine width in the maxilla are associated with buccally displaced canines [The present results showed that long-term changes in mandibular dental arch lengths were gender-related, not group-related. In EG, mandibular dental arch length increased spontaneously during the active phase of treatment, especially in males. Instead, in LG females, mandibular dental arch length started to decrease during the active phase of treatment. The present results showed that EG males benefited the most and LG females the least from the CHG treatment in terms of mandibular arch length increases. A previous study found wider mandibular arches and less decrease in the total mandibular arch length in the long term among patients treated with CHG compared with patients without CHG treatment [CHG treatment is usually two-phase treatment aiming to reduce the complexity of later orthodontic treatment. The majority of the participants in both groups needed second-phase treatment. Fixed and eruption guidance appliances may affect dental arch dimensions, but the prevalence of these appliances was similar in both groups. The rigid functional appliance generally has no effect on dental arch dimensions. Increased need for extractions in LG compared with EG confirms that the earlier approach decreases the need for permanent extractions. The effect of extractions on dental arch length was statistically tested by excluding participants with permanent tooth extractions. Because no significant influence on the results was found, dental casts with permanent tooth extractions were not excluded from the final statistical analysis.In this study, the force of 500 g for the use of CHG was chosen for both groups. According to the latest studies, the use of light force (300 g) is recommended in CHG treatment [When evaluating the long-term effects of CHG treatment, it is important to be conscious of normal dental arch development. Longitudinal studies of normal occlusion have shown a tendency for length decrease and maxillary width stability during follow-up. It has been stated that normal dental arch development is difficult to distinguish from relapse after orthodontic treatment [