Temporary Anchorage Devices

1. Dealing with Difficult Anchorage SituationsDealing with Difficult Anchorage Situations
with Orthodontic Miniscrew Implantswith Orthodontic Miniscrew Implants
Presenter: Dr. Waqar Jeelani

2. LayoutLayout
• History of skeletal anchorage
• Biological basis of mini-implant anchorage
• Types of Temporary Anchorage Devices (TAD)
• Advantages of using TADs
• Treatment planning for Miniscrew Implant (MI) placement
• Selection of a MI system
• Things to consider before placing a MI
• Insertion technique
• Biomechanical consideration using MI
• Uses of MI in difficult anchorage situations

3. • 1945 - Gainsforth and Higley - concept of skeletal
anchorage using vitallium implants
• 1969 - Branemark - concept of osseointegration using
titanium implants
• 1985 - Kokich – concept of deliberately induced
ankylosis of a deciduous tooth
• 1990’s – Commercially available miniscrew implants
• 1997 – Kanomi – K1 system of osseointegrated
miniscrews
Anchorage
History of Skeletal AnchorageHistory of Skeletal Anchorage

4. Biological Basis of Miniscrew ImplantBiological Basis of Miniscrew Implant
AnchorageAnchorage
• Miniscrew implants are
– Made of titanium alloy
– Have a smooth machined surface
– Not surface treated
• Osseointegrated implants

5. Biological Basis of Miniscrew ImplantBiological Basis of Miniscrew Implant
AnchorageAnchorage
• At the time of insertion
– Devitalization of 1 mm of peri-implant bone
– Close bone implant contact  Primary stability
– Local inflammatory response (similar to RAP)
– Bone remodeling  Secondary stability
– Loading  More bone formation

6. Biological Basis of Miniscrew ImplantBiological Basis of Miniscrew Implant
AnchorageAnchorage
Hounsfield Classification of Bone Density
•D1: Dense compact bone
•D2: Dense to thick porous compact bone on the outside and
coarse trabecular bone on the inside
•D3: Porous compact and fine trabecular bone
•D4: Fine trabecular bone
•D5: Immature, non-mineralized bone
D1 D2 D3 D4

7. Types of TADsTypes of TADs
• Osseointegrated (surface treated – need lag time)
– Palatal implants
– Onplants
– Retromolar implants
– Dental implants
• Non-osseointegrated (smooth surface – immediate
loading)
– Miniscrew implants (MI)
– Miniplates

8. Advantages and Uses of TADsAdvantages and Uses of TADs
• Patients with hypodontia
• Asymmetric tooth movements
• Treatment of occlusal cant
• Alternative to orthognathic surgery
• Retreatment cases
• Cases of poor patient compliance

9. Things to Consider before Placing a MIThings to Consider before Placing a MI
• Patient related factors
– General factors
• Smoking
• Age
• Infective endocarditis
• Diabetes mellitus
• Bone diseases and use of medicines
– Local factors
• Oral hygiene
• Quality bone
• Tooth roots and other vital structures

10. Things to Consider before Placing a MIThings to Consider before Placing a MI
• Reducing the risk of complications
Bittencourt LP, Vasconcellos M, Mucha J. The optimal position for insertion of orthodontic
miniscrews. Rev Odonto Cienc. 2011; 26 (2): 133-138.

11. Things to Consider before Placing a MIThings to Consider before Placing a MI
• Biomechanical utilization
– Force vector
– Magnitude of force/torque
– Force vs couple
– Direction of tooth movement

12. Selection of a MI SystemSelection of a MI System
• Design characteristics
– Pitch – tight vs loose
– Length – 6 – 10 mm
– Diameter – 1.3 – 2 mm
– Shape – Conical, cylindrical, mixed
– Tip – Thread forming vs thread cutting
– Surface – Smooth or roughened
• Ease of use
– Need for a pilot hole
– Need for soft tissue punch
– Insertion torque – insertion devices

13. Insertion TechniqueInsertion Technique
• Drill-free method
• Screw is placed directly in the cortical bone
• Pre-drilling method
• A hole of diameter smaller than the miniscrew is drilled in
bone
• Speed of < 30 rpm
• Screw is inserted with less insertion torque
• Pilot drilling method
• A small round / fissure bur is used
• Secure initial penetration of drill-free implants

14. Insertion TechniqueInsertion Technique
• Rinse with a 0.12% chlorhexidine solution
• Apply a topical anesthetic gel
• Anesthesia with 2% lidocaine with epinephrine
• Quarter of a single 1.8 ml ampule is sufficient
• Will not completely anesthetize the PDL

15. Insertion TechniqueInsertion Technique
• Determine the site by placing a probe parallel to the long axis
of the teeth or a radiograph
• Pinpoint mark is made at the planned area with explorer
• Miniscrew is mounted on driver and secured on cortical bone
• Clockwise roations at less than 1/4 rotation per second
• Detach driver from screw by pulling in the axis of the screw
• Primary stability – Periotest scores (-3 to 10)

16. Biomechanical Consideration using MIBiomechanical Consideration using MI
• Loading Time - Immediate
• Loading Technique - Direct vs Indirect
• Loading Force - 300-400gm
• Loading Torque - 11000 gm/mm

17. Uses of MI in Difficult Anchorage SituationsUses of MI in Difficult Anchorage Situations
• Intrusion of upper or lower anterior teeth
• Intrusion of upper posterior teeth
• Mesialization of molars
• Correction of crossbite
• Distalization of molars
• Retraction of anterior teeth
• Use of MI with functional appliances

18. Intrusion of Upper or Lower Anterior TeethIntrusion of Upper or Lower Anterior Teeth
• Force system for enmass intrusion of upper anterior
teeth

19. Intrusion of Upper or Lower Anterior TeethIntrusion of Upper or Lower Anterior Teeth
• Force system for enmass intrusion of upper anterior
teeth

20. Intrusion of Upper Posterior TeethIntrusion of Upper Posterior Teeth
• Intrusion of supra erupted upper posterior tooth/teeth

21. Intrusion of Upper Posterior TeethIntrusion of Upper Posterior Teeth
• Intrusion of posterior teeth

22. Intrusion of Upper Posterior TeethIntrusion of Upper Posterior Teeth
• Intrusion of posterior teeth

23. Mesialization of MolarsMesialization of Molars

24. Mesialization of MolarsMesialization of Molars

25. Correction of CrossbiteCorrection of Crossbite
Villela HM, Santos Sampaio AL, Bezerra F. Use of orthodontic miniscrews in asymmetrical
corrections. Dental Press J Orthod. 2008;13:107–117.

26. Distalization of MolarsDistalization of Molars
• Nance button fixed with miniscrews

27. Distalization of MolarsDistalization of Molars
• Pendulum appliance fixed with miniscrews

28. Distalization of MolarsDistalization of Molars
• Open coil assembly fixed with miniscrews

29. Distalization of MolarsDistalization of Molars
• Use of transpalatal arch with miniscrews

30. Distalization of MolarsDistalization of Molars
• Use of split palatal arch with miniscrews

31. Retraction of Anterior TeethRetraction of Anterior Teeth
• Biomechanical consideration

32. Retraction of Anterior TeethRetraction of Anterior Teeth
• Use of power arm
Nanda, R. Biomechanics and Esthetic Strategies in Clinical Orthodontics. St. Louis, MO: Elsevier
Saunders; 2005.

33. Retraction of Anterior TeethRetraction of Anterior Teeth
• Completion of retraction
– Change of force system

34. Use of MI with Functional AppliancesUse of MI with Functional Appliances
• Treatment of Class II malocclusion
Uzuner F, Aslan BI. Miniscrew Applications in Orthodontics. In: Current Concepts in Dental
Implantology. Turkyilmaz I, editor. ISBN 978-953-51-1741-4.

35. Use of MI with Functional AppliancesUse of MI with Functional Appliances
• Treatment of Class II malocclusion
Luzi C, Luzi V, Melsen B. Mini-implants and the efficiency of Herbst treatment: a preliminary
study. Prog Orthod. 2013 Jul 31;14:21.

36. Use of MI with Functional AppliancesUse of MI with Functional Appliances
• Treatment of Class III malocclusion

37. ConclusionConclusion
Miniscrew implants have become increasingly
popular over the last few years. Easy use, versatile
designs and immediate loading remains their top merits.
Their use may reduce the number of surgical and
extraction cases and greatly facilitate the treatment of
patient with low compliance, borderline surgical needs
and those requiring retreatment.

38. Thank You!