Original article
Occlusal changes in orthodontically treated subjects 40 years after treatment and comparison with untreated control subjects

https://doi.org/10.1016/j.ajodo.2020.05.027Get rights and content

Highlights

  • Occlusal changes in treated and untreated groups were compared over 40 years.

  • Maxillary and mandibular anterior crowding increased more in the treated group.

  • Maturational changes in the treated group differed from those in the untreated group.

  • Relapse contributes to greater changes in crowding and arch width in treated subjects.

Introduction

The objective of this study was to compare the aging changes of the dental arches in orthodontically treated and untreated subjects after a 4-decade follow-up period.

Methods

This retrospective study analyzed 2 groups. The treated group comprised 29 patients (11 male, 18 female) presenting with Class I or Class II malocclusions orthodontically treated with extractions of 4 first premolars. Dental models taken at pretreatment (12.84 years), posttreatment (14.95 years), and long-term posttreatment (51.37 years) were evaluated. The untreated (control) group consisted of 22 untreated patients with dental models taken at 13.32, 17.82, and 60.95 years of age. The dental models were digitized, and the following variables were evaluated: Little irregularity index, intercanine, interpremolar and intermolar widths, arch length, arch perimeter, overjet, and overbite. Interphase comparison of the treated group was performed with repeated measures analysis of variance and Tukey tests. Intergroup comparisons were performed using t tests (P <0.05).

Results

Crowding was corrected with treatment but relapsed significantly in the long term. Intercanine width increased with treatment and decreased in the long term. Interpremolar and intermolar widths, arch perimeter, and length decreased with treatment and continued to decrease long-term posttreatment. Overjet and overbite were corrected with treatment and remained stable in the long term. From posttreatment to long-term posttreatment, a greater crowding increase was observed in the treated group than in the untreated group. The treated group demonstrated a greater decrease in mandibular intercanine and maxillary and mandibular interpremolar widths than the untreated sample. Overbite increased in the treated group and decreased in the untreated group. The multiple regression analysis showed that previous 4-premolar extractions orthodontic treatment is significantly associated with anterior crowding in the long term.

Conclusions

In the long-term, the treated patients showed relapse of crowding and a decrease in arch form. Long-term changes of treated patients were different from untreated subjects. Relapse might have contributed to greater changes in incisor crowding and arch widths observed in the treated patients.

Section snippets

Material and methods

This study was approved by the Ethics Committee in Human Research of the Bauru Dental School, University of São Paulo. Sample size calculation was based on an α significance level of 5% and a β of 20% to detect a minimum difference of 0.8 mm, with a standard deviation (SD) of 0.74 for the maxillary irregularity index.16 The sample size calculation showed the need for 22 patients in each group.

Two study samples were analyzed. The orthodontically treated group comprised retrospective records of

Results

Intraclass correlation coefficients of the variables varied from 0.92 to 0.99, indicating excellent intrarater agreement.33 The variable with the widest limit of agreement was the maxillary arch perimeter (−1.12 and 1.19).

The groups were comparable regarding sex distribution (Table II) and initial age (Table II). The untreated group was older in the T2 and T3 time points and had a greater follow-up period than the treated group (Table II).

Because groups were not comparable regarding follow-up

Discussion

Initial age was similar in both groups. However, the treated patients were younger than untreated patients in the second and third evaluations (Table II). Although this is a limitation of our study, because no previous comparison between treated and untreated patients with a follow-up >30 years is known, the study results are valid. The difference in T2 was approximately 3 years, and at T3 was approximately 9 years. However, we speculate that changes in the occlusion from the fifth to the sixth

Conclusions

  • 1.

    The treated group showed significant crowding relapse in the long-term, showing a moderate irregularity in the long-term follow-up in maxillary and mandibular anterior teeth.

  • 2.

    Maxillary and mandibular arch forms tended to decrease, and overjet and overbite remained stable in the long-term in the treated group.

  • 3.

    Long-term posttreatment changes of the treated group showed a greater increase of maxillary and mandibular anterior crowding than the untreated group maturational changes.

  • 4.

    Intercanine and

Author credit statement

Karina Maria Salvatore Freitas contributed to conceptualization, methodology, formal analysis, investigation, data curation, writing original draft, visualization, and project administration; Camila Massaro contributed to methodology, validation, investigation, and data curation; Felicia Miranda contributed to methodology, investigation, and data curation; Marcos Roberto de Freitas contributed to resources, data curation, manuscript review and editing, and visualization; Guilherme Janson:

References (52)

  • C. Massaro et al.

    Maturational changes of the normal occlusion: a 40-year follow-up

    Am J Orthod Dentofacial Orthop

    (2018)
  • S.E. Bishara et al.

    Arch width changes from 6 weeks to 45 years of age

    Am J Orthod Dentofacial Orthop

    (1997)
  • J. Driscoll-Gilliland et al.

    An evaluation of growth and stability in untreated and treated subjects

    Am J Orthod Dentofacial Orthop

    (2001)
  • L. DeGuzman et al.

    The validation of the Peer Assessment Rating index for malocclusion severity and treatment difficulty

    Am J Orthod Dentofacial Orthop

    (1995)
  • L.F. Canuto et al.

    Influence of rapid palatal expansion on maxillary incisor alignment stability

    Am J Orthod Dentofacial Orthop

    (2010)
  • R.M. Little

    The irregularity index: a quantitative score of mandibular anterior alignment

    Am J Orthod

    (1975)
  • J.A. McNamara et al.

    A comparison of the Herbst and Frankel appliances in the treatment of Class II malocclusion

    Am J Orthod Dentofacial Orthop

    (1990)
  • C.M. Mills et al.

    Posttreatment changes after successful correction of Class II malocclusions with the twin block appliance

    Am J Orthod Dentofacial Orthop

    (2000)
  • G. Glenn et al.

    Nonextraction orthodontic therapy: posttreatment dental and skeletal stability

    Am J Orthod Dentofacial Orthop

    (1987)
  • K.C. Dyer et al.

    Relapse revisited--again

    Am J Orthod Dentofacial Orthop

    (2012)
  • A.E. Erdinc et al.

    Relapse of anterior crowding in patients treated with extraction and nonextraction of premolars

    Am J Orthod Dentofacial Orthop

    (2006)
  • J.L. Vaden et al.

    Relapse revisited

    Am J Orthod Dentofacial Orthop

    (1997)
  • C.L. Quaglio et al.

    Stability and relapse of maxillary anterior crowding treatment in Class I and Class II Division 1 malocclusions

    Am J Orthod Dentofacial Orthop

    (2011)
  • J.P. Ormiston et al.

    Retrospective analysis of long-term stable and unstable orthodontic treatment outcomes

    Am J Orthod Dentofacial Orthop

    (2005)
  • A. Stenvik et al.

    A 57-year follow-up of occlusal changes, oral health, and attitudes toward teeth

    Am J Orthod Dentofacial Orthop

    (2011)
  • S.E. Bishara et al.

    Longitudinal comparisons of dental arch changes in normal and untreated Class II, Division 1 subjects and their clinical implications

    Am J Orthod Dentofacial Orthop

    (1996)
  • Cited by (11)

    • Authors’ response

      2022, American Journal of Orthodontics and Dentofacial Orthopedics
    View all citing articles on Scopus

    All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported.

    View full text