Comparison of 2 comprehensive Class II treatment protocols including the bonded Herbst and headgear appliances: a double-blind study of consecutively treated patients at puberty.
BACKGROUND
The aim of this clinical trial was to compare the effects of 2 protocols for single-phase comprehensive treatment of Class II Division 1 malocclusion (bonded Herbst followed by fixed appliances [BH + FA] vs headgear followed by fixed appliances and Class II elastics [HG + FA]) at the pubertal growth spurt.


METHODS
Fifty-six Class II patients were enrolled in the trial and allocated by personal choice to 2 practices, where they underwent 1 of 2 treatment protocols (28 patients were treated consecutively with BH + FA, and 28 patients were treated consecutively with HG + FA). All patients started treatment at puberty (cervical stage [CS] 3 or CS 4) and completed treatment after puberty (CS 5 or CS 6). Lateral cephalograms were taken before therapy and 6 months after the end of comprehensive therapy, with an average interval of 28 months. Longitudinal observations of a matched group of 28 subjects with untreated Class II malocclusions were compared with the 2 treated groups. Analysis of variance (ANOVA) with post-hoc tests was used for statistical comparisons. Discriminant analysis was applied to identify preferential candidates for the BH + FA protocol on the basis of profile changes (advancement of the soft tissues of the chin).


RESULTS
The success rate (full occlusal correction of the malocclusion after treatment) was 92.8% in both treatment groups. The BH + FA group showed a significant increase in mandibular protrusion. The increase in effective mandibular length (Co-Gn) was significantly greater in both treatment groups when compared with natural growth changes in the Class II controls. Significantly greater improvement in sagittal maxillomandibular relationships was found in the BH + FA group. Retrusion of maxillary incisors and mesial movement of mandibular molars were significant in the HG + FA group. The BH + FA group showed significantly greater forward movements of soft-tissue B-point and pogonion compared with both the HG + FA and the control groups. Two pretreatment variables were significant (F = 4.48; P <0.01) in predicting the posttreatment amount of mandibular soft-tissue improvement in the BH + FA group: Co-Go-Me and pogonion to nasion perpendicular.


CONCLUSIONS
Class II treatment with either protocol during the pubertal growth spurt induces significant favorable dentoskeletal and occlusal changes. Functional jaw orthopedics had a greater favorable impact on the advancement of the chin. The clinical indications for the preferential use of the Herbst appliance at puberty are a small mandibular angle and mandibular retrusion before treatment. When treated with the BH + FA protocol, these Class II patients have the greatest probability of achieving significant improvement in the profile by advancement of the soft tissues of the chin.
Baccetti
Tiziano
T
Department of Orthodontics, University of Florence, Florence, Italy. t.baccetti@odonto.unifi.it
Franchi
Lorenzo
L
Stahl
Franka
F
D016022:Case-Control Studies; D002508:Cephalometry; D002680:Chin / Q000473:pathology; D002985:Clinical Protocols; D015331:Cohort Studies; D001840:Dental Bonding; D003766:Dental Occlusion; D004311:Double-Blind Method; D005115:Extraoral Traction Appliances; D005145:Face / Q000033:anatomy & histology; D005544:Forecasting; D006801:Humans; D007180:Incisor / Q000473:pathology; D008137:Longitudinal Studies; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008334:Mandible / Q000254:growth & development / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D008445:Maxillofacial Development / Q000502:physiology; D008963:Molar / Q000473:pathology; D009666:Nose / Q000473:pathology; D017289:Orthodontic Appliances, Functional; D011627:Puberty; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods; D016896:Treatment Outcome; D014716:Vertical Dimension