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Article: Cephalometric and occlusal changes following maxillary expansion and protraction

TitleCephalometric and occlusal changes following maxillary expansion and protraction
Authors
Issue Date1998
PublisherOxford University Press. The Journal's web site is located at http://ejo.oxfordjournals.org/
Citation
European Journal Of Orthodontics, 1998, v. 20 n. 3, p. 237-254 How to Cite?
AbstractA prospective clinical trial was conducted to determine the cephalometric and occlusal changes following maxillary expansion and protraction. Twenty Southern Chinese patients (eight males and 12 females with a mean age of 8.4 ± 1.8 years) with skeletal Class III malocclusions were treated consecutively with maxillary expansion and a protraction facemask. Growth adaptation of these patients was followed for 2 years after removal of the appliances and compared with a control group of subjects with no treatment. Lateral cephalometric radiographs were used to quantify the skeletal and dental changes before treatment (T1), immediately after treatment (T2) and 2 years after removal of appliances (T3). With 8 months of treatment (T2 - T1), overjet was overcorrected from a -2.0 to 3.5 mm. The maxilla moved forwards by an average of 2.1 mm and the molar relationship was improved to a Class I dental arch relationship. The palatal and occlusal planes were tilted upward 1.0 and 2.0 degrees, respectively. Two years following removal of the appliances (T3 - T2), a positive overjet was maintained in 18 out of 20 patients. The maxilla continued to move forwards in the treated subjects similar to the controls. The mandible outgrew the maxilla. In most instances, dental compensation with proclination of the maxillary incisors was observed. The palatal plane returned to pre-treatment value. The occlusal plane continued to tilt upward due to eruption of the molars and proclination of the incisors. Analysis of dental casts showed a significant increase in maxillary intercanine (2.2 mm) and intermolar widths (2.3 mm) with 7 days of rapid palatal expansion followed by maxillary protraction. The percentage relapse in maxillary intermolar widths was 30-45 per cent after 1 year, in most cases with minimal retention. In the mandibular arch, the concurrent increase in intermolar width (2.3 mm) was primarily due to buccal uprighting of the posterior molars when the maxilla was protracted into a Class I skeletal relationship and was stable after 1 year. The results of this study indicate stability of orthopaedic treatment of Class III malocclusions directed at the maxilla. Despite some relapse, a net improvement in maxillomandibular relationship and a positive overjet was maintained in 18 out of 20 patients at the end of the follow-up period.
Persistent Identifierhttp://hdl.handle.net/10722/49405
ISSN
2015 Impact Factor: 1.44
2015 SCImago Journal Rankings: 1.090
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorNgan, Pen_HK
dc.contributor.authorYiu, Cen_HK
dc.contributor.authorHu, Aen_HK
dc.contributor.authorHägg, Uen_HK
dc.contributor.authorWei, SHYen_HK
dc.contributor.authorGunel, Een_HK
dc.date.accessioned2008-06-12T06:41:43Z-
dc.date.available2008-06-12T06:41:43Z-
dc.date.issued1998en_HK
dc.identifier.citationEuropean Journal Of Orthodontics, 1998, v. 20 n. 3, p. 237-254en_HK
dc.identifier.issn0141-5387en_HK
dc.identifier.urihttp://hdl.handle.net/10722/49405-
dc.description.abstractA prospective clinical trial was conducted to determine the cephalometric and occlusal changes following maxillary expansion and protraction. Twenty Southern Chinese patients (eight males and 12 females with a mean age of 8.4 ± 1.8 years) with skeletal Class III malocclusions were treated consecutively with maxillary expansion and a protraction facemask. Growth adaptation of these patients was followed for 2 years after removal of the appliances and compared with a control group of subjects with no treatment. Lateral cephalometric radiographs were used to quantify the skeletal and dental changes before treatment (T1), immediately after treatment (T2) and 2 years after removal of appliances (T3). With 8 months of treatment (T2 - T1), overjet was overcorrected from a -2.0 to 3.5 mm. The maxilla moved forwards by an average of 2.1 mm and the molar relationship was improved to a Class I dental arch relationship. The palatal and occlusal planes were tilted upward 1.0 and 2.0 degrees, respectively. Two years following removal of the appliances (T3 - T2), a positive overjet was maintained in 18 out of 20 patients. The maxilla continued to move forwards in the treated subjects similar to the controls. The mandible outgrew the maxilla. In most instances, dental compensation with proclination of the maxillary incisors was observed. The palatal plane returned to pre-treatment value. The occlusal plane continued to tilt upward due to eruption of the molars and proclination of the incisors. Analysis of dental casts showed a significant increase in maxillary intercanine (2.2 mm) and intermolar widths (2.3 mm) with 7 days of rapid palatal expansion followed by maxillary protraction. The percentage relapse in maxillary intermolar widths was 30-45 per cent after 1 year, in most cases with minimal retention. In the mandibular arch, the concurrent increase in intermolar width (2.3 mm) was primarily due to buccal uprighting of the posterior molars when the maxilla was protracted into a Class I skeletal relationship and was stable after 1 year. The results of this study indicate stability of orthopaedic treatment of Class III malocclusions directed at the maxilla. Despite some relapse, a net improvement in maxillomandibular relationship and a positive overjet was maintained in 18 out of 20 patients at the end of the follow-up period.en_HK
dc.format.extent420 bytes-
dc.format.mimetypetext/html-
dc.languageengen_HK
dc.publisherOxford University Press. The Journal's web site is located at http://ejo.oxfordjournals.org/en_HK
dc.relation.ispartofEuropean Journal of Orthodonticsen_HK
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.subject.meshExtraoral Traction Appliancesen_HK
dc.subject.meshMalocclusion, Angle Class III - therapyen_HK
dc.subject.meshPalatal Expansion Techniqueen_HK
dc.subject.meshCephalometryen_HK
dc.subject.meshDental Arch - anatomy & histologyen_HK
dc.titleCephalometric and occlusal changes following maxillary expansion and protractionen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0141-5387&volume=20&issue=3&spage=237&epage=254&date=1998&atitle=Cephalometric+and+occlusal+changes+following+maxillary+expansion+and+protractionen_HK
dc.identifier.emailYiu, C:ckyyiu@hkucc.hku.hken_HK
dc.identifier.emailHägg, U:euohagg@hkusua.hku.hken_HK
dc.identifier.authorityYiu, C=rp00018en_HK
dc.identifier.authorityHägg, U=rp00020en_HK
dc.description.naturepublished_or_final_versionen_HK
dc.identifier.doi10.1093/ejo/20.3.237en_HK
dc.identifier.pmid9699402-
dc.identifier.scopuseid_2-s2.0-0032088810en_HK
dc.identifier.hkuros32510-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0032088810&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume20en_HK
dc.identifier.issue3en_HK
dc.identifier.spage237en_HK
dc.identifier.epage254en_HK
dc.identifier.isiWOS:000075155000004-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridNgan, P=7006250823en_HK
dc.identifier.scopusauthoridYiu, C=7007115156en_HK
dc.identifier.scopusauthoridHu, A=18344040200en_HK
dc.identifier.scopusauthoridHägg, U=7006790279en_HK
dc.identifier.scopusauthoridWei, SHY=7401765260en_HK
dc.identifier.scopusauthoridGunel, E=7004426388en_HK

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