Long-term changes of hard-tissue in borderline cases with extraction vs. nonextraction treatment
- VernacularTitle:正畸临界病例拔牙与非拔牙治疗其硬组织变化的长期观察
- Author:
Yan LIU
;
Wei HUANG
;
Tianmin XU
- Publication Type:Journal Article
- Keywords:
Orthodontics,corrective;
Tooth extraction;
Cephalometry;
Compararative study
- From:
Journal of Peking University(Health Sciences)
2003;0(06):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate hard-tissue changes in borderline cases with extraction and non-extraction during treatment and follow-up stages.Methods:Five associate professors,who were from Peking University School and Hospital of Stomatology,were asked to make judgment on the cases with full pre-treatment records for discriminating the borderline cases from extraction and non-extraction cases.Fifty-four borderline cases with full treatment records which had been out of treatment for at least 2 years were followed.Twenty-one cases with follow-up records were collected including 8 extraction cases and 13 non-extraction cases.Cephalometric measurements were preceeded in IDAS(Image and Database Analysis System) software program.Results:In extraction group,significant changes of SNB,SNPg in A-P direction and that of ArGo/ANSMe,MP/SN in vertical direction were present during the follow-up stage,while the overjet was stable.In non-extraction group,only decrease of proclination of lower incisor and increase of overjet were present without any skeletal changes during the follow-up stage.In comparison of the two groups,no skeletal and dental changes showed statistically significant difference except for MP/SN and ArGoGn in pre-treatment stage,while dental characteristics in relation to upper and lower incisor(L1/NB,L1-NB,L1-AP,U1-AP,U1/L1) showed statistically significant difference between the two groups after treatment.But in follow-up stage,the skeletal and dental pattern tended to be similar for both groups only except for the proclination of lower incisor.Conclusion:The similarities of skeletal and dental pattern are demonstrated in extraction and non-extraction group before treatment.Dental changes are the major post-treatment changes in the two groups.In follow-up stage,counter-clockwise rotation of mandible is unique in extraction group,which is likely a hepful factor for stability of overjet,while lingual tipping of lower incisor in non-extraction group without skeletal changes may contribute to overjet relapse.
