DENTAL ARCH SIZE: SAPIENCE, SCIENCE, SOLUTION

Introduction The current longitudinal study involved evaluation of 3 transversal parameters of the maxillary arch, affecting the stability of the orthodontic treatment result. Aim The aim was to estimate the long-term dynamics of the intercanine distance, anterior arch width and the apical base width of the maxilla. Materials and methods 145 orthodontic patients were divided in two groups. Group I included 104 subjects; for each maxillary intercanine distance, anterior arch width and apical base width were registered in three time periods: T1: in the beginning of treatment T2: after finishing orthodontic treatment T3: after orthodontic treatment and early retention period 2 – 5 years. Group II consisted of 41 patients. Periods T1 and T2 were the same as group I; period T3 considered the late retention period – 5 years and over. In both groups patients were further divided according to dentition stage: early mixed dentition; late mixed dentition; forming permanent dentition; formed permanent dentition; permanent dentition with at least one erupted third molar. The methods included biometric measurements of the anterior arch width, the apical base width and the intercanine distance plaster study models, introducing an original method. Results In group I the maxillary intercanine distance increased with 0.91 mm in T1-T2 and 1.33 mm in the T1-T3. In group II an increment of 1.56 mm in the maxillary intercanine distance for the T1-T2 and 0.89 mm for T2-T3 were observed. For the entire T1-T3 it increased with 2.45 mm. Anterior arch width of the maxilla increased with 6.77 mm in T1-T2 in group I, but remains 6.84 mm in T1-T2 for group II. Apical base of the maxilla has 1.66 mm increase in the early retention period, whereas in late retention period it decreases with 1 mm. Conclusions Intercanine distance increased to its maximum during the orthodontic treatment. In the early and late retention period an insignificant increment was observed. Maxillary arch width was significantly increased after orthodontic treatment. In the early and late retention period anterior arch width had a minor increase, clinically insignificant. The apical base in Group I was increased, and in Group II a 1 mm decrement was observed. Keywords: intercanine distance, arch width dynamics, apical base, retention period