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Biomechanics of Mini-Implant Placed in the Palate
Presentation Preference: Oral Presentation Mini-impalnts placed in the palate have benefit of higher success rate and less possibility
of root damage. Palatal mini-implant can be applied as a single mini-implant and dual mini-implants connected with a connecting plate
connecting the mini-implants over the mucosa. Single palatal mini-implant can be used for anchorage reinforcement by indirect
anchorage. When connecting transpalatal arch to the palatal mini-implant, mesial tipping moment should be negated to prevent mesial
movement of molars during extraction space closure. Also, the mini-implant should be placed as anterior as possible to minimize the
mesial movement of molars. In dual mini-implant connected with a plate applications, various attachments (usually Burstone lingual
bracket) can be attached to the connecting plate connecting the mini-implants. And then, various levers or springs can be inserted to
the attachment on the connecting plate and therefore various force systems can be made. In this presentation, various cases using
mini-implants placed in the palate including distalization, protraction, intrusion of maxillary molars and traction of impacted canine will be
presented and its biomechanics will be analyzed based on the FEM study results.
Influence Of Insertion Torque And -Site On Failure Rates Of Orthodontic Mini-Implants - A
Prospective Clinical Study
Presentation Preference: Oral Presentation Aim: Mini-implant failure rates of approximately 10%–30%
as described in the literature are still not satisfactory. This clinical study investigated the effect of insertion
torque and the insertion site on failure rates of orthodontic mini-implants.
Material and Methods: The study was conducted on a total of 493 orthodontic mini-implants placed in 284
patients (128 male, 156 female; age 19.3±9.6 years). The relationship between insertion torques,
insertion sites, mini-implant-coupling (tandem implant) and failure of the mini-implants was analysed.
Results: The overall failure rate was 14.6 % (n=72). There was a significant difference of mean insertion
torques between the failed (8.0±4.8 Ncm) and the successful group (11.4±5.7 Ncm) (P=0.0013). Below
an insertion torque of 7 Ncm the risk of implant failure increased significantly. The lowest failure rates
were found in the anterior palate (5.6%). Coupling of two mini-implants in the line of force increased the
mini-implant stability significantly.
Conclusions: Failure rates of mini-implants depend on the insertion torque, site of insertion and usage of
coupled implants. Below a value of less then 7 Ncm the risk of failure increases. The anterior palate
compares very favorably with the alveolar ridges of the maxilla and the mandible in terms of failure rates.