الفهرس 
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Abstract
This prospective randomized clinical trial was performed to evaluate the skeletal, dentoalveolar and soft tissue effects of Forsus FRD mounted on a newly designed maxillary and mandibular hybrid (metal/acrylic) splints. These splints would allow the Forsus FRD to be used as a phase 1 appliance for correcting Class II malocclusion in patients with limited amount of growth remaining or uncooperative patients who failed to comply with the conventional removable functional appliances.
Sample size calculation was carried out and resulted in enrollment of 20 subjects in the study. The selected female subjects had inclusion criteria of skeletal Class II malocclusion due to deficient mandibles, normal or horizontal growth pattern and CVM stage 3 or 4 as evident on the lateral cephalometric radiograph obtained as part of the routine diagnostic records for the patients. The subjects were randomly allocated to two groups; group 1 (HSF) and group 2 (HS-FMS). Only one patient dropout has occurred in the HS-FMS group.
A full skull CBCT scan was taken for each patient before beginning of the treatment (T1). Banding of the maxillary and mandibular molars was done followed by impressions to allow for construction of the hybrid splints in the laboratory. The new design of the hybrid splints was made by the authors to provide sufficient splinting within the maxillary and mandibular arches during FFRD treatment.
In both groups, the splints were cemented in the patient’s mouth followed by fitting of the Forsus FRD as per manufacturer’s instructions. In the HS-FMS, interradicular miniscrews were inserted bilaterally in the mandible between the first molar and second premolar. The miniscrews were then anchored to the mandibular splint using elastic chain exerting an initial force of 200 gm.
The patients were then followed up every 3 weeks until bilateral Class I canines and molars relationship was obtained with normal overjet. The appliance was then removed and the patients were referred for uptake of the final CBCT (T2). A relapse period of 2-3 months was allowed before starting the fixed appliance therapy for the patients, during which no means of retention or any Class II mechanics were employed. The clinical results showed very good stability of occlusion and profile as well as better occlusion interdigitaion (Appendix V).
A custom-made 3D analysis was made to evaluate the skeletal, dentoalveolar and soft tissue effects of the appliance in the two groups. The measurements were then obtained from the software after landmark identification and were statistically analyzed to obtain the results of the study.
from the clinical and statistical analysis results, and within the limitations of this study, the following conclusions could be withdrawn:
1- The new treatment protocol of using Forsus FRD mounted directly on hybrid splints with or without miniscrew anchorage as a phase 1 treatment was successful in treating patients with Class II malocclusion. This protocol can be used in patients with limited amount of growth available or patients uncompliant with removable functional appliance wear.
2- The addition of miniscrews to augment the anchorage in the mandibular arch resulted in less mandibular incisor proclination and protrusion.
3- The results obtained were a combination of skeletal (significant headgear effect) and dentoalveolar effects (retroclination of maxillary incisors and proclination of mandibular incisors).
4- The soft tissue profile showed significant improvement by the FFRD treatment in most of the patients in both treatment groups with reduction of angle of facial convexity and reduction of the nasolabial and mentolabial angles. However, some patients’ soft tissue profile improvement was less than others indicating some variability in soft tissue response during treatment.