Please use this identifier to cite or link to this item:
Scopus Web of Science® Altmetric
Type: Journal article
Title: The extraction of permanent second molars and its effect on the dentofacial complex of patients treated with the Tip-Edge appliance
Author: Greatrex, P.
Sampson, W.
Richards, L.
Twelftree, C.
Citation: European Journal of Orthodontics, 2002; 24(5):501-518
Publisher: Oxford Univ Press
Issue Date: 2002
ISSN: 0141-5387
Statement of
Paul A. F. Greatrex, Wayne J. Sampson, Lindsay C. Richards and Colin C. Twelftree
Abstract: The aim of this investigation was to assess the dentofacial changes in a group of patients consecutively treated with Tip-Edge appliances and the extraction of four permanent second molars by one specialist orthodontic practitioner. Before and after treatment lateral cephalograms and study cast measurements of 45 individuals, 26 females (mean age 13.8 years) and 19 males (mean age 13.9 years), were collated and statistically analysed. Cephalometric variables that exhibited, before treatment, significant sex differences, included SNA, SNB (both smaller in males, P < 0.05) and U1-NA degrees (P < 0.05), nasolabial angle (P < 0.05), and upper lip length P < 0.01 (all larger in males). After treatment, sex differences were demonstrated for SNA (smaller in males, P < 0.05), mandibular length (P < 0.01), upper face height (P < 0.05), lower face height (P < 0.01), anterior face height (P < 0.001), posterior face height (P < 0.01), nasolabial angle (P < 0.05), and upper lip length and thickness (P < 0.001; all larger in males). For the cast analysis, before treatment differences indicated larger values for males than females for lower arch inter-canine, premolar, and molar widths, arch depth (all P < 0.05), tooth size, and arch length (P < 0.01). Similar findings were noted in the upper arch except for inter-canine and premolar arch width. Despite most arch variables displaying sex differences, no gender effect was found for irregularity or crowding parameters. The same variables exhibited significant sex differences and changes after treatment (except tooth size, lower arch depth, and upper arch inter-canine width). Overall, the pattern of correction exhibited by the subjects included dental, skeletal, and soft tissue changes. Males tended to have greater mean increases in mandibular skeletal and soft tissue variables compared with females. Both males and females had increases in most dental arch variables measured from the study casts. Both sexes demonstrated a small uprighting, but statistically non-significant distalizing of the buccal segments. The lower incisors in the sagittal plane revealed a mean tendency to remain in their pre-treatment positions, with some individual variation. Overall, the treatment results were considered favourable, but case selection appeared to bias towards Angle Class I skeletal patterns of average to slightly reduced facial height, overbite and overjet < or = 4 mm, lip competence, no incisor protrusion, and moderate tooth size to arch length discrepancy (3-3.5 mm lower arch, 1 mm upper arch). Further evaluation of third molar eruption responses may provide insight into appropriate timing of second molar extractions.
Keywords: Molar
Malocclusion, Angle Class II
Treatment Outcome
Tooth Extraction
Orthodontic Appliances
Orthodontics, Corrective
Maxillofacial Development
Sex Characteristics
Time Factors
Models, Dental
Description: Copyright © 2002 Oxford University Press
DOI: 10.1093/ejo/24.5.501
Published version:
Appears in Collections:Aurora harvest 2
Dentistry publications

Files in This Item:
There are no files associated with this item.

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.