INVISALIGN

Rabab khursheed

CONTENTS INTRODUCTIONHISTORY KESLING SETUPESSIX RETAINERSINVISALIGNMATERIALSSCANNING PROCESS SOFTWAREVIRTUAL DIAGNOSTIC SETUP ATTACHMENTSCLIN CHEKSTAGINGMECHANICSADVANTAGESCONCLUSION

Moving of teeth without bands,brackets and wires was suggested as early as 1945 by Dr. Kesling Later Nahoum (vaccum formed dental contour appliance ,1964) and others (pontiz,1971, mcnamara 1985) wrote about various types of overlay appliances such as invisible retainers.

Kesling introduced the positioner as a final orthodontic finishing appliance , pliable rubber appliance Pontiz invisible retainer

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Minor tooth movements have also been achieved by a technique developed by raintree essix 1993 (New Orleans, La)This technique uses clear aligners formed on plaster models of teeth The aligners are modified with devots by special heated pliers which produce forces to push on individual teeth , and windows to create space for the teeth to move This type of appliance can correct only mild discrepancies

Essix retainers by Sheridan et all Copolymer essix sheet material Rinchause et all 1988 jco did a comparison between essix and hawleys and said essix may cause some percentage of open bite but is better

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Creating space Space within the applianceSpace within the dentition

Described by Sheridan JCO 1994Can be made canine to canine can also be used as a pontic .030 MIL Essix plastic sheet, which is reduced to .015" during thermoforming.

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Space in the appliance

Space in dentition

Inducing force Hilliard thermoforming pliers heated to 200 f Thermoformed projection

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Mounding 1 mm thick composite

Types of tooth movements Lateral movement

Torque

Rotation

Extrusion and intrusion

Invisalign Align technology ,inc (santa clara) introduced the invisalign system several years ago Invisalign takes the principals of kesling and raintree essix even further , using computer aided computer sided manufacture technology compared with laboratory techniquesFabricate a series of custom appliances that are esthetic and removable and can move teeth from beginning to the end

Kesley wirth and Zia chisti , two MBA students from Stanford university ,founded Align Technology in April 1997 Today the company is based in Santa clara, California ,employs over 800 employees and has subdivisions in Europe, mexico and costa rica

Types of invisalign treatment

The invisalign process

History and clinical examination Patient selectionTreatment submission ( impressions + records)Clinchek setup Aligner fabrication and delivery treatment monitoringfinishing

Initial Consultation and Records : -Impressions & Diagnostic Models-Photographs( intra-oral, facial ) -Radiographs ( panoramic cephalometric-periapical)

Clinical and Radiologic Examination of the teeth and periodontal tissues : -regular check-up for caries and existing restorations-control of the active periodontal problems -determine the need for extraction of impacted third molars and teeth with bad prognosis-rule out root resorption( orthodontic relapse cases)

Initial consultation and records

IMPRESSION MATERIALSSingle step Polyvinyl siloxane material like- AQUASIL (dentsply ,uk)

Dual phase impression techniquePentamix 2

Aligns standard quality impressionsExtends more than 2mm beyond the free gingival margins Free of gross distortion, bubbles or ruptureCapture all erupted teeth including the terminal molars Minor restorations can be restored if high-quality intra oral photographs are available

Poor impressions are rejected since fitting and design of the aligners will largely depend upon the details included in the impressions

Invisalign prescription form A systematic and organized process that permits providing the Invisalign technical department with the complete data regarding the diagnosis and treatment plan for the individual case . This information will aid the Align technicians to elaborate the virtual treatment plan or ClinCheck

Laboratory and technical procedures Impressions scanning Preparation of virtual dental models Virtual bite registrationTooth separation (on the virtual models)Staging of tooth movementsElaboration of clincheck Clincheck review by clinician (approve or modify)Aligners production and delivery

Scanning processLaser scanning Destructive scanning Computerized tomography

CT scan of impressions Elaboration of 3D virtual dental modelsTriangulation method

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BIte registration using TREAT software

Tooth is painted and segmentation is done using tooth shaper software

Final setup of occlusion and staging of tooth models

Clin check

Clincheck review by the doctor.

Aligner fabrication Step 1 Resin models created by steriolithography

Step two-Aligners fabricated using biostar thermoplastic machine

Attachments They are small pieces of light cured composite resins bonded temporarily on the tooth surfaceHelps in tooth movement and aligner retention Initially the technician designs a virtual resin which is transformed into a steriolithograph model and an aligner called the template aligner is fabricated from the same,this is used to make the actual attachments in the patients mouth

Tooth movements

rotations

Compliance indicator

Case reports

Thirty upper and 20 lower aligners were used to close the open bite, derotate the lower premolars, and close the anterior spaces. The refinement phase required another 10 maxillary aligners seven for a 1.1mm extrusion of the maxillary incisors and three for retraction and space closure.20 months of treatment

Treatment of anterior open bite with invisalign system,Werner, Julia and iris, JCO 2010

Class II correction with invisalign system ,Werner, Julia and iris, JCO 2010

23 months of treatment

Treatment of Severe Maxillary Crowding Using Invisalign and Fixed Appliances, ALDO and RAFFAELLA, JCO 2009

Extraction of first premolarsClass III elastics T loops -4 months 36 aligners 23 months of treatment

Surgical-Invisalign Treatment of a Patient with Class III Malocclusion and Multiple Missing Teeth, elena et al, JCO 2010

Advantages EstheticsComfortRemovabilityBonding to enamel defectsNo root resorptionLess pain and discomfortNon traumaticHygiene Can be used with any restoration or crownDoesn't alter speech

University of pacific and university of florida 71

Less chair time and armamentarium Good vertical controlFewer emergenciesPrecise control of each toothControls bruxismGreat for special patients Bleaching during treatment

Disadvantages Cannot treat all types of malocclusions Extraction cases are difficult to treat Patient compliance Very high cost Changing treatment plan Inter proximal reduction Need for clinical experience

Comparison Outcome assessment of Invisalign and traditional orthodontic treatment compared with the American Board of Orthodontics objective grading system. Djeu et al ,AmJ Orthod 2005the passing rate for invisalign was 27% lesser than that for bracesInvisalign patients finished treatment 4 months soonerInvisalign was deficient in correcting large antero posterior discrepenciesStrength of invisalign was there ability to correct anterior tooth rotations

A comparison of treatment impacts between Invisalign aligner and fixed appliance therapy during the first week of treatment. Miller et al , Am J Orthod 2007 March Aim of this study was to evaluate different life impacts between subjectsInvisalign group showed less impact in each quality of life functional , psychosocial ,and pain

Study by koji Fujiyama progress in orthodontics 2014.75

Invisalign and traditional orthodontic treatment postretention outcomes compared using the American Board of Orthodontics objective grading system. Kuncio et al ,Angle orthod 2007 Total alignment score with invisalign was more Relapse in cases treated with invisalign was more

Alternatives available in india Clear path Dental Clear bite aligners

Conclusion All in all invisalign is a great alternative to braces ,owing to its comfort level and ease of use. Though its not very cost effective, we hope in the future newer technology and materials will make it more affordable.More research in the field of complex tooth movement is still needed, but apart from that , invisalign has the potential to replace conventional orthodontic appliances.

References Invisalign and traditional orthodontic treatment postretention outcomes compared using the American Board of Orthodontics objective grading system. Kuncio et al ,Angle orthod 2007A comparison of treatment impacts between Invisalign aligner and fixed appliance therapy during the first week of treatment. Miller et al , Am J Orthod 2007 March Outcome assessment of Invisalign and traditional orthodontic treatment compared with the American Board of Orthodontics objective grading system. Djeu et al ,AmJ Orthod 2005Contemporary orthodontics : proffit

The invisalign system: Orhan C Tunkey Sheridan et al :essix retainer JCO 1993