Download Orthodontic Miniscrew Implants

Orthodontic Miniscrew Implants
Dr. Zaid Al-Dewachi
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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
History of Skeletal Anchorage
• 1945 - Gainsforth and Higley - concept of skeletal
anchorage using vitallium implants
• 1969 - Branemark - concept of osseointegration using
titanium implants
• 1985 - Kokich – concept of purposely induced
ankylosis of a deciduous tooth
• 1990’s – Commercially available miniscrew implants
• 1997 – Kanomi – K1 system of osseointegrated
miniscrews
Biological Basis of Miniscrew Implant
Anchorage
• Miniscrew implants are
– Made of titanium alloy
– Have a smooth machined surface
– Not surface treated
• Osseointegrated implants
Biological Basis of Miniscrew Implant
Anchorage
• At the time of insertion
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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
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
D1
D2
D3
D4
Types of TADs
• Osseointegrated (surface treated – need lag time)
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Palatal implants
Onplants
Retromolar implants
Dental implants
• Non-osseointegrated (smooth surface – immediate
loading)
– Miniscrew implants (MI)
– Miniplates
Advantages and Uses of TADs
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Patients with hypodontia
Asymmetric tooth movements
Treatment of occlusal cant
Alternative to orthognathic surgery
Retreatment cases
Cases of poor patient compliance
Things to Consider before Placing a MI
• Patient related factors
– General factors
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Smoking
Age
Infective endocarditis
Diabetes mellitus
Bone diseases and use of medicines
– Local factors
• Oral hygiene
• Quality bone
• Tooth roots and other vital structures
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): 133-138.
Things to Consider before Placing a MI
• Biomechanical utilization
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Force vector
Magnitude of force/torque
Force vs couple
Direction of tooth movement
Selection of a MI System
• Design characteristics
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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
Insertion 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 (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
Insertion Technique
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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
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)
Biomechanical Consideration using MI
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Loading Time
Loading Technique
Loading Force
Loading Torque
- Immediate
- Direct vs Indirect
- 300gm
- 11000 gm/mm
Uses of MI in Difficult Anchorage Situations
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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
Intrusion of Upper or Lower Anterior Teeth
• Force system for enmass intrusion of upper anterior
teeth
Intrusion of Upper or Lower Anterior Teeth
• Force system for enmass intrusion of upper anterior
teeth
Intrusion of Upper Posterior Teeth
• Intrusion of supra erupted upper posterior tooth/teeth
Intrusion of Upper Posterior Teeth
• Intrusion of posterior teeth
Intrusion of Upper Posterior Teeth
• Intrusion of posterior teeth
Mesialization of Molars
Mesialization of Molars
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.
Distalization of Molars
• Nance button fixed with miniscrews
Distalization of Molars
• Pendulum appliance fixed with miniscrews
Distalization of Molars
• Open coil assembly fixed with miniscrews
Distalization of Molars
• Use of transpalatal arch with miniscrews
Distalization of Molars
• Use of split palatal arch with miniscrews
Retraction of Anterior Teeth
• Biomechanical consideration
Retraction of Anterior Teeth
• Use of power arm
Nanda, R. Biomechanics and Esthetic Strategies in Clinical Orthodontics. St. Louis, MO: Elsevier
Saunders; 2005.
Retraction of Anterior Teeth
• Completion of retraction
– Change of force system
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 978-953-51-1741-4.
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. 2013 Jul 31;14:21.
Use of MI with Functional Appliances
• Treatment of Class III malocclusion
Thank You!