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temporary skeletal anchorage devices   TSADs.docx
temporary skeletal anchorage devices   TSADs.docx
temporary skeletal anchorage devices   TSADs.docx
temporary skeletal anchorage devices   TSADs.docx
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temporary skeletal anchorage devices   TSADs.docx
temporary skeletal anchorage devices   TSADs.docx
temporary skeletal anchorage devices   TSADs.docx
temporary skeletal anchorage devices   TSADs.docx
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temporary skeletal anchorage devices TSADs.docx

  1. 1 Dr. Mohammed Alruby Temporary skeletal anchorage devices TSADs Prepared by Dr. Mohammed Alruby
  2. 2 Dr. Mohammed Alruby Temporary skeletal anchorage devices TSADs Histology: =Branemark and Co-workers 1955 reported the successful Osseo integration of titanium implant in bone = Gainforth and Higley 1945 placed metallic vitallium screws in dog ramus = Linkow (1969 – 1970) used the mandibular blade implant in patient to apply class II elastics = Sherma 1978 placed 1st orthodontic implant = Block and Hoffman 1995 introduced the on plant to provide orthodontic anchorage Classification of implant for orthodontic anchorage: I- According to shape and size: 1- Conical cylindrical: Mini-screw implant Palatal implant Prosthodontic implant 2- Mini-plate 3- Disc implant (on plant) II- According to implant –bone contact: 1- Osseo integration 2- Non osseo integration III- According to the application: 1- Used only for orthodontic purpose ASAD 2- Used for prosthodontic and orthodontic purpose (prosthodontic implant) Mini-screws: Gained considerable important due to less surgical procedure Titanium mini-screws may be an ideal anchorage system because: - More dependability - Well accepted by patients - Can immediately loaded - Simple to insert and remove, conform to anchorage needs It can be losded with force range from 50 to 300, from 1.2mm –2mm in diameter, and 6 – 10mm in length Mini-plates: Are comprised of bone plate and fixation screws Made from pure titanium that is bio-compatible Mini-plates consists of: 1- Head compartment: Exposed intra-orally and positioned outside the dentition so it does not interfere with tooth movement It has three continuous hooks for attachment of force It has two different types of head component based on the direction of the hooks 2- Arm: Is trans-mucosal and available in three different lengths: Short: 10.5mm Medium: 13.5mm
  3. 3 Dr. Mohammed Alruby Long: 16.5mm To accommodate individual morphologic differences 3- Body component: Positioned sub-periosteal and is available in three different configurations: T plate Y plate L plate On plants: These are button-type implant used in palatal region They serve as anchorage source for expansion as well as maxillary protraction Flat disk shaped available in 8 and 10mm in diameter Nomenclature: The term TAD however is a misnomer in the context of absolute anchorage because other appliances such as headgear and mandibular lingual arch can also be classified as TADs The term temporary skeletal anchorage device is preferred (TSAD). Ironically this abbreviation is also pronounced TAD and s remaining silent Types of anchorage: 1- Direct anchorage: When TSAD is used directly to move a tooth, should take in consideration, the center of resistance of the tooth or teeth to be moved in relation to location of TSAD 2- Indirect anchorage: Occurs when a tooth or group of teeth are connected to TSAD that acts as periodontal skeletal anchorage unit, allowing for another tooth or group of teeth to move against this stabilized unit Angle of insertion: = to avoid root injury, some clinicians have advised inserting TSAD at an angle of 30 – 40 degree in maxilla and 10 – 20 degree in mandible instead of perpendicular to the bone = more acute entry angle will result in increased stress because of the greater amount of cortical bone, increased stress may draw more cytokines, macrophage and other inflammatory mediator to the site, possibly resulting in high risk of TSAD failure through loss of primary stability ** a finite element analysis and Cadaver study by Woodall et al 2011 demonstrate that, TSAD placed at 90 degree to bone provided greater anchorage resistance than 60 or 30 degree placements. Also this study refutes the concept that, having more length lead to more resistance and stability and the angle was not a factor in stability ** Lim and colleague 2008, reported that, increased torque can cause degeneration of bone at the implant –tissue interface, also increased torsional stress during placement can result in TSAD bending which can lead to TSAD fracture and small cracks in the per-implant bone Immediate loading: Because TSAD stability is based on primary stability, or interlocking of the threads of TSAD into bone, so immediate loading is possible A finite elements study suggested that immediate loading should limited to 50gm of force in 2mm diameter, other studies concluded that immediate loading can reach to 200gm of force
  4. 4 Dr. Mohammed Alruby TSAD removal: Simple procedure and local anesthesia not needed, provided that, there is no soft tissue overgrowth the same driver that used to screw the TSAD also used to unscrew it If TSAD not removed, Melson and Verna 2005 advised to wait 3 to 7 days after initial removal attempt because micro-fracture and bone remodeling may assist loosening of TSAD Risks and complications 1- Root damage: = One of the risks of TSAD placement is root contact and damaged, which can lead to - Devitalization - Osteo-clerosis - Ankylosis of the teeth = Enough clearance should be present when placing TSAD between roots and confirm the good position by radiograph = Kadioglu et al demonstrate repair and healing of cementum within a few weeks after removal of TSAD Some authors recommended that TSAD placed between roots should had 2mm clearance, take periapical radiograph is valuable than panorama to monitor the proximity of the TSAD to the root 2- Slippage: Slippage of TSAD and damage the periodontium and soft tissue in area where the bone may slope This can increase the post-operative pain; these areas include: - Infra-zygomatic buttress - Bony place on alveolar ridge - Retro-molar pad - Buccal cortical shelf - Exostosis if present To avoid slippage put TSAD at 90 degree angle to bone at these areas 3- Nerve injury: Careful and knowledge about nerve anatomy is important to prevent nerve injury during insertion Nerves at risk: - Inferior alveolar nerve - Long buccal nerve - Mental nerve - Greater palatine nerve Because peripheral nerves have the capacity to regenerate, minor nerve damaged is usually transient and manifest as paresthesia with recovery in 6 months, treatment may involve corticosteroids or laser therapy 4- TSAD fracture: Fracture can occur in TSAD because it has potential to partial Osseo integration that can cause: - Fracture occur during removal - Fracture occurs if torque applied during removal exceeds the force that TSAD withstand during removal - Fracture occur in TSAD with small diameter less 1mm If fracture deep in bone, requires removal in addition surgical procedure with drill to remove
  5. 5 Dr. Mohammed Alruby TSAD not be inserted beyond its neck because this can add torsional stress to TSAD neck which can cause TSAD loosening and potential fracture 5- Air embolus / emphysema: If air enter the sub-mucosa, soft tissue distention can occur, resulting in air embolus This condition occurs when using high speed hand piece or air-water syringe is used on bone or under the soft tissue Clinically: - Mucosal swelling - Cervicofacial swelling - Hearing loss - Orbital swelling - Otalgia - Mild discomfort During insertion avoid air water syringe and manage bleeding by cotton Areas at risk during insertion: - Retro-molar pad - Buccal alveolar bone - Maxillary zygomatic regions Management: - TSAD insertion stopped - Ice pack should apply to decrease swelling - Once swelling has stopped patient send to emergency room - This swelling typically resolves after 1 week 6- Over-heating of bone: TSADs should be placed with controlled force and speed to prevent over heating of bone Also use irrigation and controlled the torque of driver 7- Perforation into sinus: Can must be taken to ensure that TSADs do not perforate maxillary and nasal sinuses If risk exist, shorter one is used less 6mm If less than 2mm of TSAD perforates the sinus, healing usually occurred without complication and there is no impact on stability 8- Soft tissue pathology: Labial or buccal mucosa adjacent to TSAD head, may be traumatized especially if TSAD has sharp edges, or inserted in lose mucosa, or per-implant inflammation = if tissue hyperplasia fails to resolve with oral hygiene measures or cause patients discomfort or prevent use of mini-implant, TSAD should be removed and treatment by antibiotic to resolve inflammation 9- Pain: Some patient feel high level of pain and others has no discomfort during and after insertion The majority of patients appear to experience mild pressure- related pain at the time of insertion and up to 24 hours of low level pain, this is self-limiting controlled by analgesics N: B:
  6. 6 Dr. Mohammed Alruby When patient come for TSAD removal due to high pain or discomfort local anesthesia is usually not required and indeed patients find that injection sensation is worse than the actual discomfort from TSAD. 10-Mini-implant migration: This depend on: - The head and neck to body ratio - Degree of bone support - Relative force level Sometimes TSAD may tip or translate bodily in the direction of applied force This is a problematic, because, there is approximation occur between TSAD and bracket or crown and can cause soft tissue impingement. This appears to be risk in patient with high risk in anchorage requirements 11-Bio-mechanical side effects: = Conventional fixed appliances may exhibit some biomechanical effects such as: - Frictional binding - Tooth tipping - Anchorage loss = And these effects are usually localized to single tooth or multiple of teeth = TSAD provide more anchorage in all three dimensions and extrinsic to fixed appliance = The most side effect occurs by using TSAD when make oblique vector of force on flexible wire that lead to roller coaster bowing phenomena. = but with rigid arch wire causing combination of molar intrusion and incisor extrusion Contraindication of TSADs In patients with: 1- Serious systemic disease 2- Use of bis-phosphonate medication 3- Un-controlled hemorrhagic disorders 4- Bone metabolism disorders 5- Psychotic disease 6- Weakened immune-resistance and leukocyte dysfunctions 7- Illness requiring periodic using of steroids 8- Nickel or titanium allergy 9- Previously irritated bone 10-Patients with diabetes mellitus 11-Poor oral hygiene 12-Drugs, alcohol, or tobacco abuse, smokers 13-Xerostomia 14-High dental anxiety 15- Anticoagulant medication Sites of implant placement In maxilla: 1- Tuberosity area 2- Infra-zygomatic crest area 3- Between 1st and 2nd molar bucally
  7. 7 Dr. Mohammed Alruby 4- Between 1st molar and 1st premolar bucally 5- Between canine and premolar bucally 6- Between incisors facially 7- Mid palatal area In mandible: 1- Retro-molar area 2- Between 1st and 2nd molar bucally 3- Between 1st molar and 2nd premolar bucally 4- Between canine and premolar bucally 5- Under roots of incisors facially Uses of TSAD 1- Retraction of anterior teeth 2- Uprighting molars 3- Mesio-distal tooth movements 4- Molars mesialization 5- Open bite correction: achieved by molar intrusion (skeletal anchorage) 6- Intrusion of anterior teeth as well as molar 7- Distalization of 1st and 2nd molars supported by pendulum 8- Reinforcement of anchorage 9- To treat border line cases with non-extraction method 10-Where a symmetric tooth movement is needed N: B: Factors controlling predrilling of implant site: 1- Mini-implant insertion torque- IT: The amount of torque during placement of an implant reflect the resistance of mini-implant, this resistance is proportional to amount of bone compression during placement and therefore increase with greater cortical – bone thickness 2- Primary stability: According to Melsen and Coaster, primary stability is an important factor for mini-implant success Primary stability expresses the initial stability of recently placed implant Primary stability is important during the healing and remodeling period, especially when implant is immediately loaded 3- Secondary stability: Implant stability after the placement site has healed and is consequences of bone formation and remodeling at the implant bone interface and the surrounding bone N: B: = orthodontists are the ideal clinicians to place TSAD because of their understanding of bio- mechanics of tooth movement = TSADs should be placed in keratinized gingiva and cortical bone = the success rate of TSAD is approximately 85% and this is depending on the proper treatment plane and site selection = TSADs diameter should more than 1.3mm to avoid fracture
  8. 8 Dr. Mohammed Alruby = correction of skeletal open bite with TSAD should be undertaken in patients with class I or mild class II, but in class III skeletal relationship
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