OBJECTIVE: The aim of this study was to evaluate long-term changes in the pharyngeal airway dimensions after functional appliance treatment in adolescents with skeletal Class II malocclusions. METHODS: Pharyngeal airway dimensions were compared between subjects with skeletal Class II malocclusions (n = 24; mean age: 11.6 +/- 1.29 years) treated with a Class II bionator and age-matched control subjects with skeletal Class I occlusions (n = 24; mean age: 11.0 +/- 1.21 years) using a series of lateral cephalograms obtained at the initial visit (T0), after treatment (T1), and at the completion of growth (T2). RESULTS: The length of the nasopharyngeal region was similar between adolescents with skeletal Class I and Class II malocclusions at all time points, while the lengths of the upper and lower oropharyngeal regions and the pharyngeal airway areas were significantly smaller in the skeletal Class II adolescents before treatment when compared to the control adolescents (p < 0.05). However, following treatment with a functional appliance, the skeletal Class II adolescents had increased pharyngeal airway dimensions, which became similar to those of the control subjects. CONCLUSIONS: Functional appliance therapy can increase the pharyngeal airway dimensions in growing adolescents with skeletal Class II malocclusions, and this effect is maintained until the completion of growth.
Activator Appliances* ; Adolescent* ; Humans ; Malocclusion*

The purpose of this study was to evaluate treatment effects of the modified Teuscher appliance (MTA) in early Class II division 1 malocclusion. For this purpose, treatment effects of the bionator were compared with those of the MTA. The twenty subjects who were treated excellently with bionator and MTA were selected in each group. In pre- and post-treatment lateral cephalograms, 50 variables were measured, and then the differences between pretreatment and posttreatment data of the bionator and the MTA were statistically evaluated by t-test. The results were as follows : 1. The linear measurements that showed large difference between the bionator group and the MTA group are U1 to FH, U1 to PP, U6 to FH, U6 to PP, Ar-Pog, ramus height, L1 to A-Pog, L1 to facial plane (p<0.05). 2. The angular measurements that showed large difference between the bionator group and the MTA group are SNB, SNA, FABA, APDI (p<0.05). 3. The measurements of the growth pattern such as facial height ratio, FMA, SN-MP angle showed no difference between two groups (p>0.05). These results suggest that the bionator influence the mandiblar growth and lower dentoalveolar structures more than the MTA, and the MTA influence upper jaw and upper dentoalveolar structures more than the bionator comparatively in early Class II division I malocclusion.
Activator Appliances ; Jaw ; Malocclusion* ; Pemetrexed

OBJECTIVE: To establish proper diagnosis and treatment plan for skeletal Class II malocclusions, some important factors to consider are the patient's skeletal morphology, prognosis as well as the treatment effects. Therefore, the present study analyzed the effects of activator treatment on different skeletal patterns in growing Class II malocclusion patients. METHODS: A total of 116 patients (53 boys & 63 girls) in the experimental group were treated with the activator appliance. The experimental group was classified into either hyperdivergent or hypodivergent groups according to articular and gonial angles. RESULTS: Patients with hypodivergent growth patterns showed good effects of activator treatment. CONCLUSION: It seems conceivable that through classifying adolescent Class II malocclusion patients into different skeletal patterns, activator treatment effects may be predicted during the diagnosis and treatment planning stage.
Activator Appliances ; Adolescent ; Diagnosis ; Humans ; Malocclusion* ; Prognosis

The purpose of this study was to evaluate treatment effects of bionator in Class II division 1 malocclusion by FEM(Finite Element Method). The 73 subjects were classified into good result group and poor result group in reference to posttreatment molar relation, posttreatment overbite and overjet, posttreatment profile, and relapse. Pretreatment and posttreatment lateral cephalograms were taken and FEM was performed. The results were as follow; 1. There was no statistical significance in treatment changes between the sexes, and between the treatment result groups. 2. Treatment changes were not significantly different among the age groups. 3. The effect of treatment period groups on skeletal and dentoalveolar changes were analyzed using ANOVA. Body of maxilla, upper incisor, anterior face, ramus, upper anterior face, lower anterior face and treatment effect were correlated with the treatment period, but correlation coefficients were low. 4. The results of present investigation confirm that Class II bionator can assist in the correction of Class II division 1 malocclusion, mainly due to dentoalveolar changes. 5. There is significant difference in skeletal and dentoalveolar pattern between good result group and poor result group. In poor result group, maxilla was relatively downward and backward rotated, mandible was relatively backward rotated, upper incisor was in relatively lingual position, lower incisor was in relatively labial position.
Activator Appliances* ; Humans ; Incisor ; Malocclusion* ; Mandible ; Maxilla ; Molar ; Overbite ; Recurrence

The purpose of this study was to evaluate the indications of bionator in Class II division 1 malocclusion. The 48 subjects were classified into good result group(groupl) and poor result group(group2) in reference to posttreatment molar relation, posttreatment overbite and overjet, posttreatment profile, and relapse. Pretreatment lateral cephalograms were calculated and evaluated by t-test and stepwise discrminant analysis. The results were as follows; 1. In jaw bone relationship, ANB, facial convexity angle, AB to facial plane angle were significantly different between two treatment groups. In denture pattern, Ll to facial plane, Ll to A-Pog, FMIA, and Ul to facial plane were significantly different and in soft tissue profile, protuberance of lower lip and upper lip were significantly different between two treatment groups. 2. The results in according to discriminant analysis stated that Ll to facial plane, ANB, FMIA and protuberance of lower lip help prediction of treatment result of bionator. 3. 3 major influential variables were obtained by stepwise discriminant analysis - Ll to facial plane, articular angle and ANB difference. And Fisher discriminant function was made by these three major variables.
Activator Appliances* ; Dentures ; Jaw ; Lip ; Malocclusion* ; Molar ; Overbite ; Recurrence

OBJECTIVETo determine the positional changes of condyle and mandible in children treated successfully with Fränkel function regulator.

METHODS30 Angle's class II patients including 15 boys and 15 girls treated with Fränkel function regulator were selected. Superimposition of the pretreatment and posttreatment lateral cephalograms of all the patients was done on the stable bone structure of the anterior cranial base and mandible. Cartesian coordinate system was used to measure the positional changes of condyle and mandible over time by computer.

RESULTSThere was significant inferior displacement of condyle, gonion and pogonion after treatment with reference to stable bone structure of anterior cranial base. Anterior displacement of pogonion in boys was also significant. There was significantly superior and posterior displacement of condyle and posterior displacement of gonion after treatment with reference to stable bone structure of mandible.

CONCLUSIONFränkel function regulator can stimulate condylar growth and do favor to mandibular remolding.

Activator Appliances ; Cephalometry ; Child ; Female ; Humans ; Male ; Malocclusion, Angle Class II ; therapy ; Orthodontic Appliances, Functional

OBJECTIVETo investigate the biomechanics of J-hook headgear in En mass intrusion and retraction of maxillary anterior teeth and provide guidance for clinical treatment.

METHODSA three-dimensional finite element model of maxillary teeth, periodontium, straight wire appliance and maxillary bone was established in ANSYS 14.0. En mass retraction of anterior teeth with force of 1.5 N through J-hook headgear was stimulated. Force was applied mesial to lateral incisor in group A and distal to lateral incisor in group B. The force direction was 30° to the sagittal plane and 20° to 60° to the occlusal plane. Force direction to the occlusal plane was changed every 5° and 18 cases were calculated. Displacement of upper anterior teeth and stress distribution in the periodontium were analyzed.

RESULTSAs the degrees of force direction to the occlusal plane increased, the moving pattern of upper anterior teeth changed from clockwise rotation (lingual movement with intrusion) to bodily retraction and intrusion, and counter- clockwise rotation (intrusion with labial movement). With the force direction of 35° to occlusal plane applied mesial to lateral incisor or force direction of 45° to the occlusal plane applied distal to lateral incisor, bodily movement of upper anterior teeth without rotation was achieved.

CONCLUSIONSPlacement of J-hook mesial to lateral incisor enable orthodontists to maintain better en mass intrusion and retraction of upper anterior teeth. The direction of J-hook should be adjusted according to individual condition and treatment objective.

Activator Appliances ; Biomechanical Phenomena ; Finite Element Analysis ; Humans ; Incisor ; Maxilla ; Periodontium ; Tooth Movement Techniques ; instrumentation ; methods

OBJECTIVETo evaluate the effects of headgear-activator (HGAC) combination appliances on bone and dentition of juveniles with Class II division 1 malocclusion using Pancherz's analysis approach.

METHODSFifteen patients (8 males of 10-13 years old and 7 females of 9-12 years old, average age was 11.2 years old, ANB > or = 5 degrees, overjet > or =6 mm, Class II molar relation) were treated with HGAC appliance for more than 14 hours everyday and for total of 8-10 months cephalograms were taken before and after the treatment. The data was analyzed with Pancherz's analysis and pare t test (SPSS 11.5 software).

RESULTSAfter the therapy, SNA and ANB angles reduced, the change of SNB angle was trivial, pg/OLP was forward movement. The axial inclination of the lower incisors increased and of the upper incisor reduced. Overjet of the incisors was improved, in which skeletal factor was improved to 44.64% and dentition factor was 55.36%. The first molar on the mandible was forward movement. Molar relationship was also improved, in which skeletal factor was improved to 65.65%, and dentition factor was 34.35%.

CONCLUSIONHGAC can efficaciously treat Class II division 1 malocclusion with maxillary protrusion, stimulate modification of the mandibular condyle and fossa, and promote the development of the mandibles. Dentition was improved more than skeletal on overjet, and skeletal was improved more than dentition on molar relationship.

Activator Appliances ; Adolescent ; Cephalometry ; Female ; Humans ; Incisor ; Male ; Malocclusion ; Malocclusion, Angle Class II ; Mandible ; Mandibular Condyle ; Maxilla ; Molar