Australasian Dentist Issue 93

CATEGORY 38 AUSTRALASIAN DENTIST LINICAL Fig 28 Utilisation of micro-implants to protract and upright molars Fig 29 As anchor for direct molar intrusion with buccal implant Fig 30 Maintenance Factors Lingual interdental region u As anchor for direct molar intrusion along with buccal implant Characteristics of an Ideal Anchorage Device (James Cope) u Simple to use and immobile u Inexpensive u Should be immediately loadable and able to withstand orthodontic forces in small dimensions u Does not require compliance u Should be biocompatible u At a minimum, when initially placed, TADs must have primary stability and be able to withstand orthodontic force levels. Indications for use of TADs u Absolute anchorage in maximum retraction requirements. u For patients not compliant with the use of headgear, TADs are viable option for anchorage. u In case of missing first molars, TADs can provide anchorage as well as help manage the space judiciously. u For difficult tooth movements such as anterior/posterior intrusion, en- masse distalization of upper/lower arches, molar up righting and molar distalization. u In adult orthodontics for complex tooth movements. u TADs can also be used for the attachment of orthopaedic forces to jaws when there is a lack of anchorage units. u Correction of midline asymmetry and cant of occlusion. Contraindication for implant placement a) General contra-indications: The micro-implant must not be used if the patient has- – History of immune deficiency, – History of steroid therapy (in the past 6 months), – Bleeding or clotting disorders, – Uncontrolled endocrine disease, – Bone disease, – Rheumatic ailments, – Cirrhosis of the liver, or any other acute disease. b) Local contra-indications: – Osteomyelitis of the jaws, – Receives radiation therapy in the head and neck region, – Has receding gingival disease or unsatisfactory oral hygiene. Advantages The mini-implants have the following advantages: u Efficiency u Expanded range of mechanotherapy u Stable anchorage u Simplified treatment u Space gaining through distalization of posterior teeth u Nonsurgical correction of vertical excess u Narrow to allow placement between roots u Self-tapping for minimally invasive placement u Single-stage procedure u Reduced osseointegration to allow easy removal at the end of the treatment. Predictors of Clinical Failure Clinical failure is most likely related to the following: u The design and dimension of the mini- implant. u The handling at insertion and the timing and level of force applied to the host. u The quantity and quality of bone at the insertion site. Iatrogenic factors 1. Excessive heat generation when drilling, resulting in bone-tissue necrosis 2. Root injury or approximation 3. Inadequate initial mechanical stability 4. Implant contamination 5. Inflammation due to negligence of oral hygiene 6. Inflammation by gingival impingement of elastic materials 7. Injury to anatomical structures (e.g. nerve, artery, sinus) 8. Micro-implant fracture Fig 27 Bracket attached to two micro-implants placed in edentulous area to protract and upright the molar Edentulous area of mandible u For controlling teeth adjacent to edentulous space u To achieve movements as molar uprighting and other movements