Orthodontic treatment stability predictors: A retrospective longitudinal study.
OBJECTIVE
To examine medium- to long-term orthodontic treatment stability and its possible association with certain variables.


METHODS
In a retrospective longitudinal study of 70 postretention patients, the Peer Assessment Rating (PAR) index was measured at the start (T1) and end (T2) of treatment and between 4 and 10 years afterwards (T3). The stability was considered absolute when the T2 and T3 values were identical and relative when the difference was within the ±5 range.


RESULTS
Among the 70 patients, 65.8% were female and 34.2% were male. Their mean age was 14.5 years. The mean treatment length was 2.4 years. The mean retention phase was 3.3 years. The mean pre- and posttreatment PAR scores were 29.8 (T1) and 6.3 (T2). The mean T1-T2 difference was 23.6. The mean T2-T3 difference was -0.39.


CONCLUSIONS
Within the study, 7.1% presented absolute stability and 68.6% presented relative stability. Lower anterior segment alignment and overbite were the most unstable occlusal features and tended to worsen. Fixed retainer (odds ratio [OR] 0.31; 95% confidence interval [CI] 0.10-0.98) as a protective factor and years without retention (OR 1.32; 95% CI 1.03-1.68) as a risk factor are predictor variables of instability in the case of lower anterior segment alignment. The PAR value at the end of treatment (OR 1.29; 95% CI 1.08-1.54) and extractions (OR 4.76; 95% CI 1.05-21.6) before treatment are predictors for midline instability.
Paloma González-Gil
PG
de Bernabé
José María
JM
Montiel-Company
Vanessa
V
Paredes-Gallardo
Jose Luis
JL
Gandía-Franco
Carlos
C
Bellot-Arcís
D000293:Adolescent; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008310:Malocclusion / Q000628:therapy*; D018704:Orthodontic Retainers; D009971:Orthodontics, Corrective / Q000295:instrumentation / Q000379:methods*; D012008:Recurrence; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
Follow-up study; Long-term stability; Orthodontic retainer and retention; Relapse; Treatment outcome