two or more maxillary incisors for Class II Division 2 malocclusion were selected. II molar relationship, all teeth present except third molar. The samples were selected for the cusp tips of the right and left mandibular canines. 5. Mandibular. The correction of a Class II division 1 malocclusion with functional appliances is It was named, the Eruption Guidance Appliance (EGA), and was a early treatment does provide correction of the incisal relationship mainly. Angle ' s Class II malocclusion: A malocclusion in which Anterior guidance: The influence of the contacting Class II division 1 incisor relationship: The lower.
The correction of a Class II division 1 malocclusion with functional appliances is a common treatment approach in young patients 7. The activator, a widely used functional appliance, prevents the mandible from sliding backward and transfers the force to the maxilla, which is essentially the anchorage unit for the anteriorly displaced mandible 10 The literature contains a large number of studies investigating the effects of the activator appliance and response to treatment 12— Bergersen 18 developed a prefabricated elastomeric appliance into correct malocclusions.
It was named, the Eruption Guidance Appliance EGAand was a combination of a functional appliance and a tooth positioner. The property of elastomeric material could induce minor tooth movement during bite closure. The appliance was used with the same indications as most functional appliances and was ease to prescribe as it was prefabricated 19— Various modifications of the EGA have been presented during the years and the reported treatment effects were mainly dentoalveolar 22 In a Finnish prospective cohort study, children in early mixed dentition were treated with modifications of the EGA and favourable changes in overjet, overbite, crowding and sagittal relations were reported More recently, a Norwegian randomized clinical trial reported, in a short-term perspective, that the EGA seems to be effective in correcting increased overjet and overbite, Class II malocclusion, and lower anterior crowding in the early mixed dentition Prefabricated functional appliances PFAs have been used for several years and their effects have been confirmed However, no randomized clinical trial has so far evaluated the effectiveness of a prefabricated appliance compared to a custom made functional appliance.
ANGLE’S CLASSIFICATION OF MALOCCLUSION | DENTODONTICS
The aim of this study was therefore to compare the clinical effectiveness in reducing large overjet between a PFA and a slightly modified Andresen activator AA.
The null hypothesis was that the treatment effect in correcting large overjet was similar for both appliances. Andresen activator AA standardised but custom-made, slightly modified AA with opening in the front to make it easier for mouth breather. Subjects and randomization Patients that fulfilled the criteria below were invited to take part in the study.
An informed written consent was obtained from the parents and randomization was performed by lottery. At each clinic two envelopes were available one for girls and one for boys with 5 AA and 5 PFA notes for each gender. If all notes were used, participants would be available in this RCT.
The 12 general practitioners GPs engaged in the study as well as the 6 orthodontists were calibrated in the measurements of overjet, overbite, and Angle classification. Following inclusion criteria were applied: Interventions Appliances The AA was a standardised custom made, slightly modified AA with an opening in the front region to make it easier for mouth breathers. The acrylic in the lateral segments was removed, to allow eruption of the posterior teeth.
A passive maxillary labial bow was used to aid anterior retention and retrocline the maxillary incisors if they were proclined. The construction bite was taken in edge-to-edge position.
All AA were made at the same orthodontic dental lab according to a given prototype Figure 1. All PFA were ordered from the same company Figure 1. The participants were instructed to use the appliance every night and 2 hours during daytime, 12—14 hours in total.
The daytime wear could be divided into separate periods of at least 30 minutes. Initial checks were performed after 6 weeks with subsequent checks being carried out every 8th week.
Treatment protocol Following parameters were recorded and defined as: Overjet mm distance between the incisal edge of the most labial maxillary central incisor and the corresponding lower incisor in retruded position RP. Measurements were rounded off to the nearest 0.
Data was recorded at the following three stages: T0—before start of treatment.
incisor relationship - oi
The teeth all fit on a line of occlusion which, in the upper arch, is a smooth curve through the central fossae of the posterior teeth and cingulum of the canines and incisors, and in the lower arch, is a smooth curve through the buccal cusps of the posterior teeth and incisal edges of the anterior teeth.
There is alignment of the teeth, normal overbite and overjet and coincident maxillary and mandibular midlines.
The mesiobuccal cusp of the maxillary first permanent molar occludes with the mesiobuccal groove of the mandibular first permanent molar. The distal incline of the maxillary canine occludes with the mesial incline of the mandibular first premolar. The molar relationship shows the mesiobuccal groove of the mandibular first molar is DISTALLY posteriorly positioned when in occlusion with the mesiobuccal cusp of the maxillary first molar.
- Class II, Division 1 Angle malocclusion with severe proclination of maxillary incisors
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Usually the mesiobuccal cusp of maxillary first molar rests in between the first mandibular molar and second premolar. The molar relationships are like that of Class II and the maxillary anterior teeth are protruded. Teeth are proclaimed and a large overjet is present.
The molar relationships are Class II where the maxillary central incisors are retroclined. The maxillary lateral incisor teeth may be proclaimed or normally inclined.