CATEGORY 52 AUSTRALASIAN DENTIST LINICAL Gaining space in the dental arch is the most important step in treatment planning, which can be achieved by different methods, one of which is molar distalization. The most frequent dentoskeletal disharmony is the Class II malocclusion. This distoclusion may be the result of a retrognathic mandible, of a prognathic maxilla or a combination of both. Dentally, the mesiobuccal cusp of the first upper molar occludes in front of the buccal sulcus of the first lower molar. The disadvantage of this lies in the lack of available space in the upper dental arch, creating the need to utilize appliances that can generate or stretch the available space in order to act distally and transversely. There are many non-extraction treatment modalities for Class II malocclusion. One of them consists of converting the Class II molar relation into a Class I molar relation by distally displacing the upper first molars. Diagnosis Confirm the diagnosis of a forward maxillary molar position. To check the centric relation position, vertical status and the TMJ status. Radiographic assessment u Skeletal convexity and growth prediction helps to differentiate between a forward maxilla and a backward mandible. u In growing patient, growth prediction must be made to determine what the possible convexity would be with time and growth. u Absence of upper 3rd molars offers better prognosis. u Posterior crowding as indicated by distal angulation of the molars makes distalization unsuitable. Criteria for case selection u Late mixed dentition u Normal or near normal mandibular arch u Dental Class II with skeletal Class I u 3rd molars absent u Profile considerations – well-developed nose and chin u High MPA – Contraindicated u Space discrepancy – not very severe. Basic recommendations for distalization In a growing child u To relieve mild crowding u Causes permanent increase in arch length of about 2 mm on each side. Late mixed dentition u Upper molars are distalized to get a Class I relation. u End on molar relationship with mild to moderate space requirement. u Cases with a full cusp Class II molar relationship. u Class I malocclusion with highly placed or impacted canine. u Lack of space for eruption of premolars due to mesial migration of permanent first molars u Good soft tissue profile u Borderline cases u Mild to moderate space discrepancy with missing 3rd molars / 2nd molars not yet erupted u Normal or hypo-divergent growth pattern. In young patients, the best moment to distalize is before the second molars are totally erupted. The upper second molars erupt normally without impaction; meanwhile the second premolar follows the first molar distally. Mixed or permanent dentition u Recommend the extraction of the third molars. u Distalizers can provoke an undesired upper first molar rotation. u Use Class II elastics in order to reduce anterior proclination. u After the distalization is completed, place a moderate or maximum anchorage to the distalized molars. Molar Distalization Dr Geoff Hall By Dr Geoffrey Hall Unilateral or bilateral Dental Class II relation. Patients with Class I or class III molar relation Class I skeletal, Class II or end-to-end molar Patient with retrognathic profile relationship (due to maxillary protrusion but mandible is of normal length). Increased overjet (up to 5 mm). Patients with open bite tendency (skeletal or dental) Increased overbite (deep bite). Normo- or hypodivergent patients / Dolichocephalic patients / Excessive lower face Short lower face height height. Midline discrepancy. Mild to Moderate crowding (mild arch length Severe arch length discrepancy patients discrepancy. Patients with early mixed or permanent dentition. 3 molars have erupted or close to eruption Low to moderate mandibular plane angle Patients with vertical growth pattern High mandibular plane angle. Patients with minimal skeletal problems / with upper dentoalveolar protrusion / Impacted or highly placed cuspids. Gaining space (loss of arch length) due to premature loss of deciduous teeth. Patients that do not accept extractions. Favourable maxillary 2nd molar position, Maxillary first molar mesially inclined. Second molar extraction cases where the third molars are well formed and erupting properly. Indications and Contraindication for Molar Distalization
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