1. Orthodontic Miniscrew Implants
Dr. Zaid Al-Dewachi

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

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

5. Biological Basis of Miniscrew Implant Anchorage
At the time of insertion
Devitalization of 1 mm of peri-implant bone
Close bone implant contact  Primary stability
Local inflammatory response
Bone remodeling  Secondary stability
Loading  More bone formation

6. Biological Basis of Miniscrew Implant Anchorage
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
D D D D4

7. Types 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 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 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 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):

11. Things 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 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 Technique Drill-free method Pre-drilling 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 (round per minute)
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 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 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 MI
Loading Time - Immediate
Loading Technique - Direct vs Indirect
Loading Force gm
Loading Torque gm/mm

17. Uses 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 Teeth
Force system for enmass intrusion of upper anterior teeth

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

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

21. Intrusion of Upper Posterior Teeth
Intrusion of posterior teeth

22. Intrusion of Upper Posterior Teeth
Intrusion of posterior teeth

23. Mesialization of Molars

24. Mesialization of Molars

25. Correction 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 Molars
Nance button fixed with miniscrews

27. Distalization of Molars
Pendulum appliance fixed with miniscrews

28. Distalization of Molars
Open coil assembly fixed with miniscrews

29. Distalization of Molars
Use of transpalatal arch with miniscrews

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

31. Retraction of Anterior Teeth
Biomechanical consideration

32. Retraction 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 Teeth
Completion of retraction
Change of force system

34. Use 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

35. Use 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 Jul 31;14:21.

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

37. Thank You!