Posttreatment and physiologic occlusal changes comparison.
OBJECTIVE
To compare posttreatment and postretention occlusal changes with the physiologic occlusal changes caused by natural development of untreated subjects.


METHODS
The sample was divided into three groups. Group 1 comprised 97 subjects treated with four premolar extractions at a mean pretreatment (T0) age of 13.03 years, a mean posttreatment (T1, first observation) age of 15.12 years, and a mean postretention (T2, second observation) age of 20.52 years. The mean observation period (T2-T1) was 5.39 years. Group 2 comprised 58 subjects treated nonextraction at a mean pretreatment age of 12.83 years, a mean posttreatment age of 14.99 years, a mean postretention age of 20.22 years, and a mean observation period of 5.22 years. Group 3 comprised 114 untreated subjects at a mean age at T1 of 14.91 years and at T2 of 20.48 years. The mean observation period was 5.56 years. Dental casts were evaluated using the Peer Assessment Rating (PAR) index and the Little irregularity index in maxillary and mandibular arches. Changes in PAR and Little indexes were compared among the three groups by analysis of variance and Tukey tests.


RESULTS
Intergroup comparison showed that at T1 and T2 the treated groups presented smaller PAR and Little indexes than the untreated group. In the observation period, the treated groups showed greater increase in PAR and Little maxillary indexes than the untreated group. The extraction group showed a greater increase of the Little mandibular index than the untreated group.


CONCLUSIONS
The treated groups showed more changes according to PAR and Little maxillary indexes than the untreated group. The posttreatment change of the mandibular anterior crowding of the treated extraction group was greater than the mandibular crowding caused by physiologic changes in the untreated group.
Department of Orthodontics, Ingá Dental School, Maringá, Paraná, Brazil. kmsf@uol.com.br
Karina Maria S
KM
Freitas
Guilherme
G
Janson
Bryan
B
Tompson
Marcos Roberto
MR
de Freitas
Tassiana Mesquita
TM
Simão
Fabrício Pinelli
FP
Valarelli
Rodrigo Hermont
RH
Cançado
D000293:Adolescent; D000704:Analysis of Variance; D002508:Cephalometry; D003766:Dental Occlusion; D005260:Female; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000628:therapy*; D009971:Orthodontics, Corrective / Q000379:methods*; D057887:Overbite / Q000628:therapy; D018024:Peer Review, Health Care; D012008:Recurrence; D018709:Statistics, Nonparametric; D014081:Tooth Extraction; D016896:Treatment Outcome