Caries as an Etiologic Factor for Malocclusion in Adolescents

Objective: Our purpose was to determine the effect of mesial molar migration due to premature loss of deciduous teeth on need for orthodontic treatment at adolescence, and to evaluate the occlusal consequences of the migration. Subjects and methods: Our sample of 1573 13-14-year-old school children in Kuwait was selected according to cluster sampling methods, defining students in the government schools of each administrative area as six different strata, and the students in private schools as the seventh stratum. Index of Orthodontic Treatment Need (IOTN) as well as molar and canine relationship, overjet, overbite and midline deviation were scored in a well lit classroom using gloves, mirrors and spatulas. Results: Severe orthodontic treatment need with IOTN scores 5i and 4d, which are likely sequelae of the reduced perimeter of the affected quadrants, was recorded in 46.7% and 18.1% of the 108 subjects with mesial migration of one or more first molars, as opposed to in 2.8% and 10.5% of the subjects without migration, respectively, (P<0.001). The majority (77%) of these subjects had moderate to severe need for orthodontic treatment also for other reasons. Asymmetric molar and canine relationship was observed in 66.2% and 56.1% of the subjects with mesial molar migration as opposed to in 25.5% and 35.3% of those without (p<0.001). Migration of mandibular molars was associated with midline deviation (p<0.05), typically to the side of migration. No effects were detected on maxillary midline, overjet and overbite (p>0.05). Conclusions: The major effect of mesial molar migration on orthodontic treatment need is increased treatment severity of cases that would have needed orthodontic treatment for various morphologic reasons regardless of the loss of dental arch perimeter of the affected quadrants. Acknowledgements: This research was supported by Kuwait University Grant DD07/00.