Miniscrews in orthodontics
Miniscrews in orthodontics
Definition :
Miniscrews are temporary bone anchors also called mini-implants. Miniscrews are devices that provide a temporary skeletal anchor point (4 to 12 months) in the maxilla or mandible, allowing for orthodontic movements such as mesialization, distalization, intrusion, egression, or tilting.
Material Description:
The material must be biocompatible and non-toxic, and have sufficient mechanical properties for orthodontic use, while being easy to use. Most miniscrews currently on the market are made of titanium alloy.
Surgical steel miniscrews have recently been proposed due to the biomechanical properties and biocompatibility of this material.
Titanium miniscrews Steel miniscrews
CONSTITUENT PARTS:
There are currently a large number of miniscrews on the market. They are generally conical and have a similar geometry with three parts: a head, a neck and a threaded body.
The head of the miniscrew is intended to establish the connection with traction devices such as springs, ligatures or chains.
There are currently two main types of miniscrew heads on the market that the practitioner will choose depending on the treatment plan, the type of anchoring and the insertion site:
- miniscrews with three-dimensional control head
- miniscrews whose head constitutes a single anchor point such as a perforation or a button.
Bracket head miniscrew Universal miniscrew
The neck corresponds to the transmucosal part of the miniscrew. This segment is perfectly smooth in order to reduce the risk of dental plaque retention.
Measurements:
- Length of the miniscrew
A long screw is rather indicated in the presence of a thin cortex,
Conversely, if the cortex is thick (> 2 mm), a short screw can be used. A 10 mm intraosseous anchorage is generally recommended.
- Miniscrew diameter
Small diameter miniscrews allow for less risky insertion between roots. However, they have less resistance to torsion and fracture.
Set up :
Under local anesthesia, often without an injection, these mini anchors are screwed through the gum using a special screwdriver in a few minutes.
They can even be removed without anesthesia.
Example of use :
- move a molar forward to avoid implant placement and encourage the development of wisdom teeth.
- To push a molar into the bone to allow the creation of a bridge on the opposite arch.
- Move back incisors without stressing the molars.
- Pulling an impacted tooth.
- Open a preprosthetic space.
Indications :
- Insufficient dental anchorage
- Limited orthodontic appliances
- Performing difficult dental movements: molar straightening or intrusion, mass dental movements.
- Dental movements sought without unwanted effects.
Advantage :
- Reduces processing time
- Avoid the use of extra-oral auxiliary devices (such as the Delaire Mask or the FEO: Extra-oral Traction Helmet)
- Avoids the need for dental units
- Ease of use
- Reduction in the use of intermaxillary elastics.
- Several processing phases can be carried out simultaneously.
- Increased therapeutic possibilities (anterior gaps, asymmetrical shifts)
- Little painful.
- Make treatment faster, less invasive
- Sometimes avoid surgery.
- Post-operative advice :
- Taking a painkiller (paracetamol) pain felt similar to that produced by a change of bow.
- Do not run your tongue over the miniscrew
- Carefully brush the miniscrew using a soft toothbrush.
- Traction performed by the orthodontist on the miniscrew within one week of its placement.
- Failures :
– Sometimes a miniscrew does not hold, so it will be replaced in another location.
– the fracture can result from a diameter that is too thin . And it is the result of a twisting movement.
– The fracture generally occurs at the neck, which is an area of weakness.
– a lack of asepsis when installing the miniscrew, the accumulation of particles produced by the corrosion of the miniscrew in contact with the plate.
– a lack of hygiene.
– irritation of the mucous membrane.
– Damage to a dental root caused by a miniscrew results either from an error in assessing the available inter-radicular space or from an incorrect insertion axis.
– Sinus intrusion is often the result of poor assessment of sinus morphology and volume, associated with an insertion axis that is too angulated in the apical direction or with insertion of the miniscrew too high.
– In this case, the practitioner must remove it and select another site or another insertion axis which will allow the body of the screw to be completely intraosseous.
– the lesion of the mental nerve is clinically manifested by the appearance of labiomental paresthesia
– damage to the lingual nerve causes a loss of sensitivity of the tongue on the side of the miniscrew.
‐ Coverage of the miniscrew head by soft tissue occurs when the screw is inserted deeply.
Bibliography
- MASSIF L., FRAPIER L. Clinical use of mini-screws in orthodontics. Medical-Surgical Encyclopedia 2006;23:492-17.
- MELSEN B. Mini‐implants: Where are we? J Clin Orthod 2005;39:539‐547.
- MELSEN B. Indications for skeletal anchorage in orthodontics. Rev Orthop Dento Faciale 2006;40:41‐61.
Miniscrews in orthodontics
Wisdom teeth can cause infections if not removed in time.
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Inflamed gums can be a sign of gingivitis or periodontitis.
Clear aligners discreetly and comfortably correct teeth.
Modern dental fillings use biocompatible and aesthetic materials.
Interdental brushes remove food debris between teeth.
Adequate hydration helps maintain healthy saliva, which is essential for dental health.