Join me for a summary of a lecture by Ramesh Sabhlok, looking at one of the most popular sites for TAD placement, the maxillary buccal interradicular site.
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The most common site in maxilla for implant placement is between 2nd premolar and 1st molar in the keratinized gingiva.
- Buccal bone thickness
- Inter radicular distance
- Greatest bone width of bone is between 2nd premolar and 1st molar, and considered ‘safe zone’ thickness of bucco-palatal bone 10.2-11.4mm ( Pogio 2006 Angle orthodontics )
- 2nd premolar and 1st molar: 3.2mm (SD 0.6mm)- 5mm (SD 0.8mm) when 4-6mm from the CEJ, largest clearance of interradicular space in the buccal aspect of maxilla Lee 2009
- Gradually decreases apically, therefore it is advised to place the mini implant at height of 4-6 mm from CEJ, at 2 mm height only 2.7mm interradicular
- In the maxilla, the more anterior and the more apical, the safer the location becomes.
- Increased after levelling and alignment, delay placing if possible
‘SAFE DEPTH’ proposed by Ramesh
- depth of from the bone surface to the narrowest interradicular space at a given height which is safe = 3.2mm interradicular distance for 1.2mm width TAD AND 3.5mm for a 1.5mm TAD.
- Safety depth (height) is 4mm.
- 2mm depth the greatest inter radicular distance 2.4mm, not safe
- A 20-30o angle, places the interradicular aspect of the miniscrw apically, where the interradicular is the greatest. This reduces root contact, increases retention with more cortical plate engagement, allows use of longer miniscrews as well as greater distalisation prior to relocation Deguchi 2006.
Extraction of 3rd molars
- Classic papers looking at the Pendulum appliance by Kinzinger 2004 showed extraction of 3rd molars resulted in greater bodily distalisation on the maxillary arch.
- However recent CBCT paper by Lee 2019 show that with miniscrew distalisation there was no difference bodily movement with extraction of 3rd molars and non-extraction.
Concept of biologic width
1-1.5mm of periodontium surrounding the implant,
Summary from AAO 2022 lecture: Non- compliance & Predictable class II correction with Micro implant Anchorage
Episode is dedicated to the late Dr Anam Humdani, a London based dentist who tragically died aged 29
- Contents: Shanya Kapoor
- Editing and Production: Farooq Ahmed
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