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Join me for a summary of Dr Bing Fang’s lecture entitled: Biomechanical Research and clinical application of orthopaedic Treatment on Adolescent mandibular retrognathia. It was part of the first International Orthodontic Foundation online symposium, with Ravi Nanda https://www.iofglobal.org
Pathogenesis = treatment
- Retrognathic mandible average maxilla = functional appliance
- Prognathic maxilla = extractions
- If extraction and retrognathic maxilla = bimax retrusive appearance at the end
Intrusion with aligners
Clinical risk of anterior intrusion, can cause retroclination / proclination.
- Plan with assessing lower incisor inclination relative to skeletal structure from a cephalogram
- To figure out this problem they designed a finite element study to figure out what happens for different lower incisor inclinations
- If the IMPA angle exceeded 100 the intrusive force will be in front of CR resulting in a moment causing lingual root torque and buccal crown torque
- If the IMPA angle less than 100 the intrusive force will be behind the CR resulting in a moment causing buccal root torque and lingual crown torque
- Plan intrusion:
- Proclined teeth: intrusion and retraction at the same time with lingual crown torque
- Retroclined teeth: Intrusion, with labial crown torque
Advanced Mandibular Spring AMS with aligner
- Telescopic arm with spring.
- Distalization of posterior and no movement in the anterior along with anterior bit turbos
- Class II elastics are used day time, appliance at night
- Inserts into connectors which are imbedded into the aligner
- How does it work
- Finite model analysis, favourable for advancing the mandible – PDL even stress, promote mandibular growth, stress on condylar anterior aspect and posterior glenoid fossa
#alignerorthodontics #class2 #Bingfang #farooqahmed
