Approaches to Correction of Class III Skeletal Malocclusion

Approaches to Correction of frame trine Skeletal MalocclusionCombined Orthodontic and consumptional Approach in the Correction of Class leash Skeletal MalocclusionDr. Abdulaziz AlShahraniAstracWhile growth modification and camouflage orthodontic preaching offers a limited tooth root in treating some skeletal Class III malocclusion depending on the age of the affected role , Underlying skeletal severity, alignment of the teeth and the vertical facial proportions, a combination of surgical and Orthodontic therapy is the treatment of choice in all severe skeletal Class III malocclusion. In this case report I present a combination of surgical-orthodontic therapy for an adult female patient role with skeletal segmentation III malocclusion which resulted in good skeletal, dental and soft tissue alliance, with attach improvement in function and facial esthetics.KeywordsClass III malocclusion, Orthognathic Surgery, surgical orthodonticsIntroductionClass III malocclusion is conside red to be one of the most herculean and complex orthodontic problems to treat. The prevalence of class III malocclusion has been reported to be as low as 3-5% in the Caucasian population, but is higher in the Chinese and Japanese population (4-13%) (Often associated with maxillary retrusion)i,ii,iii.The etiology of class III is complex and multi component partial. However, there is usually a strong genetic contribution. Genetic factor is one of the etiological factors where one third of children with severe Class III had a parent with the same problem and one-sixth had an affected siblingiv. Racial course may play a role as the blacks have shown higher incidence than whitesv.Environmental factors appear to play an adaptiverole in the etiology of Class III malocclusionvi.Class III malocclusion can be associated with other factors such as cleft palatevii.Individuals with class III malocclusion show combinations of skeletal and dentoalveolar components. Class III malocclusion may p ass on as a result of protrusive mandible, retrusive maxilla, combination of bothviii. While the most commonly found Class III malocclusion (30%) showed a combination of mandibular protrusion and maxillary retrusion, Maxillary retrusion alone was found in 19.5% of the sample and Mandibular protrusion alone was found in 19.1% of the sampleix.These complex nature of class III requirea careful planning, amultidisciplinary approach and patient cooperationx.CaseReportA 17-year-old caucasian girl presented for orthodontic treatment because of referral from her dentist with primary complaint of un-esthetic facial and dental appearance. She has a hyper-divergent Class III skeletal and dental relationship. This is characterized by retrognathic maxilla, retroclined press down anterior teeth, with maximum active opening of 47mm with 5mm negative overjet and lateral excursions of 7 mm to both upright and left sides.The patient has an ovoid, relatively asymmetrical face with chin slightly dev iated to the left. The lip line at rest displayed approximately 2 mm of pep pill incisor. At full animation there was 7mm of upper incisal display and 2 mm of lower incisal edge. She has a slightly concave profile, and competent lipsFigure1.Pretreatment extra viva photosIntraorally, the oral mucosa was healthy. There were no periodontal pockets present. The gingival tissues were inflamed especially around the prosthetic crowns. There was no bleeding tendency buy food sometimes with brushing. Free gingival margins were near to the CEJ and attached gingiva was of normal width throughout the mouth. The frenal attachments in both disgustinges were normal. The tongue was normal in size, function and appearance. Teeth 26, 36 and 46 have been crowned. There was a lingual arch placed one year ago to maintain lower incisors position. closure analysis, she was in the permanent dentition and the 3rd molars were un-erupted. She has good oral hygiene.Frontal view Shows a dental midline disc repancy. The lower dental midline is coincidental with the facial midline while the upper midline is not coincident with the facial midline its off to the left by 2.5mm, the occlusal planewas slightly cant to the left. A negative overjet of 5 mm reported.Right and left Lateral Views Shows the canines and molars in Class III relationships. The upper occlusal view shows a U-shaped arch with well adjust anterior segment. The lower occlusal view reveals a U-shaped arch with crowding of 3.9mmFigure 2.TREATMENT OBJECTIVESOur objective is to address compensated lower incisors by proclining them to the ideal position and trend followed by increasing the horizontal projection of the maxilla to correct upper jaw retrognathism, concave profile, class III dental relationshipand negative overiet. Increased lower facial height and hyper-divergence will be turn byautorotation of the mandible after the forward motion of the maxilla and vertical reduction genioplasty.Mandibular asymmetry will be corrected by BSSO while maintaining lower incisor position.TREATMENT PROGRESSWe started Pre-surgical orthodontics using self-ligation bracket system (Roth prescription, 022slot). Leveling and alignment of maxillary and mandibular arches began with round 0.016 niti arch wires progressing to 0.0170.025 niti arch wires. Patient was referred to extract all 3rd molars at this stage. Coordinated 0.0190.025 Stainless steel then used for arch coordination before sending the patient for surgical procedureFigures 67.All the movement and prediction were planned on pre-surgical lateral cephalometric x-ray using Moorres mesh as a guide. A sheet of analyze paper over the original tracing and the outline of the mandible was drawn and trimmed making a template, another template for the maxilla was produced and placed in the post-surgical position. The mandibular autorotation then simulated accordingly. The soft tissue contours then drawn using the guidelines in literaturesxi,xii,xiiiFigure8.Cen tric relationship of Upper and lower jaws was recorded and daring bow transfer and articulation of models on a semi-adjustable articulator was done. Model surgery then performed using Erickson model blockandacrylic inter occlusal wafer splint was produced.Le fort I osteotomywas performed to advance the maxilla for 7.1 mm and Bilateral sagittal split osteotomy was carried out to correct mandibular asymmetry while maintaining the A-P position of the mandible. Vertical reduction and advancement (4mm each) genioplastythen performed to address the increased lower facial height and achieve esthetically acceptable facial profile. Rigid type of fixations were used in both arches.The patient was followed closely and the post-surgical Orthodontic was resumed 3 weeks after surgery. 0.0190.025 stainless steel changed to 0.021 0.025stainless steel to express the torque. Finishing was performed with settling elasticsfigures9-12.Six months later, resolute appliances were removed and lower fixed retainer 3-3 was cemented along with upper and lower Hawleys retainers figures 13 14.Cephalometric finding shows a good skeletal, dental and soft tissue relationship and improvement in the function and facial estheticsTable 2, Figures15-17.pre- and post-treatment cephalometrictracingsDiscussionThis case report presents a combination of surgical and orthodontic therapy for an adult female patient with skeletal and dental class III malocclusion. The magnitude of the problem was so severe and lies outside the envelope of possible correction by orthodontics alonexiv. In growing patients, early treatment with maxillary expansion and protraction can result in straightening of profile after 6 monthsxv. It can also promote more favorable psychosocial maturement and greater compliancexvi. Delaying treatment can lead to development of posterior cross bite and the subsequent development of facial asymmetryxvii.During adulthood, correction of the Class III malocclusion usually requires comple x surgical procedures to achieve a good skeletal, dental and soft tissue relationship and improve the function and facial estheticsxviii.In this case, our objective were achieved. even off lower incisors were address by proclining them to the ideal position and inclination in pre-surgical orthodontic treatmentwhile in post-surgical orthodontic treatment teeth were brought into settledocclusion.Normal skeletal relationship was achieved byLe fort I osteotomyto advance the maxilla, Bilateral sagittal split osteotomy to correct mandibular asymmetry while maintaining the A-P position of the mandible and vertical reduction and advancementgenioplastyiiiiiiivvviviiviiiixxxi.xii.xiiixivxvxvixviixviii