Retrospective analysis of orthodontic treatment outcomes and its relation to postretention stability

Abstract

Objective:The present study was designed to retrospectively evaluate Class I malocclusion cases treated with extraction of the four first premolars, aiming to establish the relationship between the quality of orthodontic treatment outcomes and the long-term occlusal stability.Material and methods:The sample comprised 94 patients of both genders, presenting Class I malocclusion, treated with extractions of the four first premolars and Edgewise mechanics. All the patients selected were whites, being 50 males and 44 females. The mean pretreatment age was 13.46 years (s.d. 1.8). The mean treatment time was 2.09 years (s.d. 0.58), the mean retention time was 1.63 years (s.d. 0.73) and the mean time of postretention evaluation was 5.31 years (s.d. 1.61). The dental casts were measured at pretreatment (T1), posttreatment (T2) and postretention (T3), by the PAR index and by the Little irregularity index, and the correction due to treatment (T1-2) and the change at the postretention period (T3-2) were calculated. The descriptive statistics was performed and the Pearson correlation coefficient was applied for the PAR and the Little indices in the total sample, among the times evaluated.Results:The mean PAR reduction due to treatment was 78.54%, and 66.6%, at the postretention stage related to pretreatment stage. Significant correlations were found for the PAR index at the times evaluated, except between T1 and T2 and between T1-2 and T3. In other words, the higher the treatment correction (T1-2), the lower the posttreatment PAR index (PAR T2) will be, and the higher will be the PAR change at the postretention period (PAR T3-2). Also, the higher the posttreatment PAR score (PAR T2), the higher will be the postretention PAR score (PAR T3).Conclusion:It was concluded that the quality of orthodontic treatment outcomes is not related to the long-term occlusal stability.

Correction of Class II, Division 2 malocclusions using a completely customized lingual appliance and the Herbst device

“…These interrelationships should be taken into account when comparing the initial weighted PAR indices of the different types of malocclusions. An average reduction in weighted PAR indices by more than 86% to values < 3.0 at the end of treatment represents a considerable improvement in percentages compared with other studies (78-86%) [6,18,21,30,36]. Likewise, evaluation of our treatment outcomes reveals an above-average improvement with a weighted PAR index of 2.9 [6,18,21,30,36].…”

“…An average reduction in weighted PAR indices by more than 86% to values < 3.0 at the end of treatment represents a considerable improvement in percentages compared with other studies (78-86%) [6,18,21,30,36]. Likewise, evaluation of our treatment outcomes reveals an above-average improvement with a weighted PAR index of 2.9 [6,18,21,30,36]. Only in those studies based on patient selection according to treatment outcome, in which only the most favorable outcomes were assessed, were the final values necessarily better [33].…”

“…Diese Zusammenhänge sollten bei Vergleichen der initialen, gewichteten PAR-Indizes verschiedener Okklusionsanomalien berücksichtigt werden. Eine mittlere Reduktion der gewichteten PAR-Indizes von über 86% auf Werte <3,0 am Ende der Behandlung (T3) stellt im Vergleich zu anderen Untersuchungen (78-86%) eine überdurchschnitt-liche prozentuale Verbesserung dar [6,18,21,30,36]. Auch die Bewertung des Behandlungsergebnisses zeigt mit einem gewichteten PAR-Index von 2,9 einen überdurchschnittlich guten Wert [6,18,21,30,36].…”

“…Eine mittlere Reduktion der gewichteten PAR-Indizes von über 86% auf Werte <3,0 am Ende der Behandlung (T3) stellt im Vergleich zu anderen Untersuchungen (78-86%) eine überdurchschnitt-liche prozentuale Verbesserung dar [6,18,21,30,36]. Auch die Bewertung des Behandlungsergebnisses zeigt mit einem gewichteten PAR-Index von 2,9 einen überdurchschnittlich guten Wert [6,18,21,30,36]. Nur in Untersuchungen mit ergebnisbezogener Patientenauswahl, bei denen nur die besten Fälle ausgewertet wurden, ergaben sich zwangsläufig bessere Werte [33].…”

“…Kein Patient wurde in die Kategorie "wenig verbessert oder verschlechtert" eingestuft. Der schlechteste von einem der kalibrierten Untersucher vergebene Score bei Behandlungsende war 10 ( [4,5,6]). …”