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Long-term stability of Class II malocclusion treated with 2- and 4-premolar extraction protocols.
Am J Orthod Dentofacial Orthop. 2009 Aug; 136(2):154.e1-10; discussion 154-5.AJ

Abstract

INTRODUCTION

The objective of this study was to cephalometrically compare the stability of complete Class II malocclusion treatment with 2 or 4 premolar extractions after a mean period of 9.35 years.

METHODS

A sample of 57 records from patients with complete Class II malocclusion was selected and divided into 2 groups. Group 1 consisted of 30 patients with an initial mean age of 12.87 years treated with extraction of 2 maxillary premolars. Group 2 consisted of 27 patients with an initial mean age of 13.72 years treated with extraction of 4 premolars. T tests were used to compare the groups' initial cephalometric characteristics and posttreatment changes. Pearson correlation coefficients were calculated to determine the correlation between treatment and posttreatment dental-relationship changes.

RESULTS

During the posttreatment period, both groups had similar behavior, except that group 1 had a statistically greater maxillary forward displacement and a greater increase in the apical-base relationship than group 2. On the other hand, group 2 had a statistically greater molar-relationship relapse toward Class II. There were significant positive correlations between the amounts of treatment and posttreatment dentoalveolar-relationship changes.

CONCLUSIONS

Treatment of complete Class II malocclusions with 2 maxillary premolar extractions or 4 premolar extractions had similar long-term posttreatment stability.

Authors+Show Affiliations

Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, SP, Brazil. jansong@travelnet.com.brNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

19651339

Citation

Janson, Guilherme, et al. "Long-term Stability of Class II Malocclusion Treated With 2- and 4-premolar Extraction Protocols." American Journal of Orthodontics and Dentofacial Orthopedics : Official Publication of the American Association of Orthodontists, Its Constituent Societies, and the American Board of Orthodontics, vol. 136, no. 2, 2009, pp. 154.e1-10; discussion 154-5.
Janson G, Leon-Salazar V, Leon-Salazar R, et al. Long-term stability of Class II malocclusion treated with 2- and 4-premolar extraction protocols. Am J Orthod Dentofacial Orthop. 2009;136(2):154.e1-10; discussion 154-5.
Janson, G., Leon-Salazar, V., Leon-Salazar, R., Janson, M., & de Freitas, M. R. (2009). Long-term stability of Class II malocclusion treated with 2- and 4-premolar extraction protocols. American Journal of Orthodontics and Dentofacial Orthopedics : Official Publication of the American Association of Orthodontists, Its Constituent Societies, and the American Board of Orthodontics, 136(2), e1-10; discussion 154-5. https://doi.org/10.1016/j.ajodo.2009.01.020
Janson G, et al. Long-term Stability of Class II Malocclusion Treated With 2- and 4-premolar Extraction Protocols. Am J Orthod Dentofacial Orthop. 2009;136(2):154.e1-10; discussion 154-5. PubMed PMID: 19651339.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Long-term stability of Class II malocclusion treated with 2- and 4-premolar extraction protocols. AU - Janson,Guilherme, AU - Leon-Salazar,Vladimir, AU - Leon-Salazar,Ruben, AU - Janson,Marcos, AU - de Freitas,Marcos Roberto, PY - 2008/09/10/received PY - 2009/01/10/revised PY - 2009/01/19/accepted PY - 2009/8/5/entrez PY - 2009/8/5/pubmed PY - 2009/8/18/medline SP - 154.e1-10; discussion 154-5 JF - American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics JO - Am J Orthod Dentofacial Orthop VL - 136 IS - 2 N2 - INTRODUCTION: The objective of this study was to cephalometrically compare the stability of complete Class II malocclusion treatment with 2 or 4 premolar extractions after a mean period of 9.35 years. METHODS: A sample of 57 records from patients with complete Class II malocclusion was selected and divided into 2 groups. Group 1 consisted of 30 patients with an initial mean age of 12.87 years treated with extraction of 2 maxillary premolars. Group 2 consisted of 27 patients with an initial mean age of 13.72 years treated with extraction of 4 premolars. T tests were used to compare the groups' initial cephalometric characteristics and posttreatment changes. Pearson correlation coefficients were calculated to determine the correlation between treatment and posttreatment dental-relationship changes. RESULTS: During the posttreatment period, both groups had similar behavior, except that group 1 had a statistically greater maxillary forward displacement and a greater increase in the apical-base relationship than group 2. On the other hand, group 2 had a statistically greater molar-relationship relapse toward Class II. There were significant positive correlations between the amounts of treatment and posttreatment dentoalveolar-relationship changes. CONCLUSIONS: Treatment of complete Class II malocclusions with 2 maxillary premolar extractions or 4 premolar extractions had similar long-term posttreatment stability. SN - 1097-6752 UR - https://www.unboundmedicine.com/medline/citation/19651339/Long_term_stability_of_Class_II_malocclusion_treated_with_2__and_4_premolar_extraction_protocols_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0889-5406(09)00504-6 DB - PRIME DP - Unbound Medicine ER -