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Twin block /certified fixed orthodontic courses by Indian dental academy

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Twin block /certified fixed orthodontic courses by Indian dental academy

  1. 1. TWIN BLOCK INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. INDEX • • • • • • • • • • • • • • • • Introduction Historical perspective Biologic Basis The Clark Cephalometric Analysis Appliance design and construction Treatment of Class II div 1 malocclusion Treatment of Class II div 2 malocclusion Treatment of anterior open bite Treatment of Class III Malocclusion Twin block therapy in mixed dentition Magnetic Twin Blocks Twin Blocks in TMJ Therapy Fixed Twin Blocks Twin block traction technique Adult treatment References
  3. 3. • Myofunctional Appliances :• According to Moyers, Myofunctional appliances are loose removable appliances designed to alter neuromuscular environment of orofacial region to improve occlusal development of craniofacial skeletal growth.
  4. 4. • Historical Perspective:• The concept of advancing the mandible by way of inclined planes is not new, with the notion of “jumping the bite”(1880) Kingsley. • “Vorbissplate” of Schwarz (1966). • The Oliver “ guide plane” • DeVincenzo and coworkers used appliance similar to developed by clark but angulation used, 90 degree to occlusal plane as opposed to 70 degree recommended by Clark.
  5. 5. Biologic Basis: • In all the experimental animals, including, most importantly, the mature adult, a large amount of bone had formed in the glenoid fossa, especially along the anterior border of the post-glenoid spine.The glenoid fossa appeared to be remodeling anteriorly.
  6. 6. Introduction of Twin Block: • The functional occlusal inclined plane is the fundamental functional mechanism of the natural dentition. • Cuspal inclines play an important role in determining the relationship of the teeth as thery erupt into occlusion. • Occlusal forces transmitted through the dentition provide a constant proprioceptive stimulus to influence the rate of growth and the trabecular structure of the supporting bone.
  7. 7. Development of Twin Block “ It is true that necessity is the mother of invention.” • Twin Blocks evolved in response to a clinical problem when a young patient , having Class II div 1 malocclusion fell down, the upper right central incisor was avulsed. Within few hours of the trauma the tooth was reimplanted .
  8. 8. • In order to prevent the adverse lip action , upper and lower bite blocks were designed which were engaged 90 degree. • The first Twin Block appliance was fitted on 7th September 1977. • It was found that, within 9 months of starting the Twin Block therapy the occlusion and overjet reduced from 9mm to 4mm in 9 months.
  9. 9. THE CLARK CEPHALOMETRIC ANALYSIS • • • • • • • • • • • • • • • • • • • The various angular and linear measurements are as follows: Cranial Base angle Mandibular plane angle Craniomandibular angle Facial plane angle Facial axis angle Condylar axis angle Mandibular arc Craniomaxillary angle Maxillary deflection Upper incisor angle Lower incisor angle Interincisal angle Position of dentition Position of upper dentition Position of lower dentition Soft tissue analysis Nasal Angle Lower lip to E- plane
  10. 10.
  11. 11. ADVANTAGES OF TWIN BLOCK • • • • • • • • • • • • • • • • Comfort Aesthetics Function Patient Compliance Facial Appearance Speech Clinical Management Arch Development Mandibular Positioning Vertical Control Facial Assymetry Safety Efficiency Age of the treatment (Early childhood to the adulthood) Integration with fixed appliances Treatment of TMJ dysfunctions
  12. 12. APPLIANCE DESIGN AND CONSTRUCTION • • • • • • A midline screw to expand the upper arch Occlusal bite blocks Clasps on the upper molars and premolars Clasps on the lower premolars and incisors A labial bow to retract upper incisors Springs to move individual teeth and to improve the archform as required • Provision for extraoral traction in some cases
  13. 13. • STANDARD TWIN BLOCK: • They are essentially for the treatment of uncrowded Class II div 1 malocclusions with good arch form and overjet large enough to allow unrestricted forward translation of the mandible to allow full correction of the distal occlusion.
  15. 15. Twin Block for arch development :• SAGITTAL DEVELOPMENT • Transverse and Sagittal Development :• Twin Blocks to Close anterior Open bite:-
  16. 16. • • • • • • Labial Bow: Delta Clasp Ball End Clasp Base Plate Heat Cure: (Advantages ) Occlusal inclined plane
  17. 17. DELTA CLASP
  18. 18. • Treatment of Class II div 1 Malocclusion ( DEEP OVERBITE) Bite Registration: •Protrusive bite is registered •Initially, 5-10 mm activation can be achieved •Edge to Edge bite with 2 m m interincisal clearance. •Bite activation should not exceed 70 % of total protrusive path. •Larger overjets require partial correction •Center lines should coincide. •Open the bite slightly beyond the clearance of freeway space, to prevent dropping off the mandible out of the bite. •In vertical dimensions 2mm interincisal is equivalent to clearance in first premolar region by 5 to 6 mm and 3mm in molar region. ( It allows, supraeruption of molars and deep bite correction.)
  19. 19. Twin Block in mixed dentition • Objectives : • Reduce the overjet and correct distal occlusion • Control overbite if the overbite is deep or an anterior open bite is present • Improve arch form by sagittal or transverse development. • [C- shaped clasps can be bonded to deciduous teeth for improved retention.]
  20. 20. Treatment of Class II div 2 malocclusion • An edge to edge construction bite is registered to correct the distal occlusion, in class II division, 2 malocclusion. • Management of Class II div 2 malocclusion by advancing the mandible and proclining the upper incisors with sagittal screws. Eruption of lower molars corrects the vertical dimensions.
  21. 21. Treatment of Class III malocclusion • Reverse twin blocks are designed to encourage maxillary development by the action of reverse occlusal inclined planes cut at a 70 degree angle to drive the upper teeth forwards by the forces of occlusion and at the same time, to restrict forward mandibular development.
  22. 22. Bite registration • • • • • Teeth closed to the maximum retrusion, leaving sufficient clearance between posterior teeth for occlusal bite blocks .This is normally achieved by recording bite with 2 mm interincisal clearance in fully retruded position. Appliance design:In many cases, the maxilla is contracted in addition to occluding in distal relation to the mandible. The three –way expansion screw to combine transverse and sagittal expansion. Opening the screw has reciprocal effect of driving upper molars distally and advancing the incisors.
  23. 23. MAGNETIC TWIN BLOCKS : • • • • • Use of the magnets in occlusal inclined plane, is a new concept. Darendeliler, Joho (1991,93,95) reported correction of Class II div 1 malocclusion with magnets. Materials Used: Samarium-Cobalt magnets Neodymium-Iron-Boron Magnets
  24. 24. Twin Blocks in Temporomandibular joint therapy :• Temporomandibular joint pain and dysfunction are related to occlusal disharmony with premature occlusal contact, causing posterior or lateral shift of the mandible from centric relation and distal displacement of the condyles. • Distal displacement of the condyle is associated with anterior displacement of the articular disc.
  25. 25. Goals of the therapy: • Relieve the pain caused by distal displacement of the condyle • Retain the muscles to a healthy pattern • Recapture the disc when possible by advancing the displaced condyles. • Move the teeth that are causing occlusal imbalance and mandibular misguidance. • Increase the vertical dimension to reduce the deep overbite.
  26. 26. The Twin Block Biofinisher • It extrudes the lower molars by vertical traction. • It stabilize the TMJ by uncreasing vertical dimensions • It has a hook for elastic, that extends above upper molars in the vestibule
  27. 27. Temporary fixation of twin block • Twin block appliances may be designed for direct fixation to the teeth by bonding. • The patients co-operation is assured if appliance is either fixed to the teeth or removable only by the operator
  28. 28. • Integration of Twin Block with fixed appliances:• A combined fixed and functional approach is necessary for correction of more complex malocclusions, in which skeletal and dental factors require a combination of orthopaedic and orthodontic techniques.
  29. 29. The twin Block traction technique:• The twin Block traction technique:• The cases in which, response to functional correction is poor , the addition of orthopaedic traction force may be considered. • Indications: • In treatment of severe maxillary protrusion. • To control a vertical growth pattern by the addition of vertical traction to intrude upper posterior teeth. • In adult treatment where mandibular growth can not assist the correction of severe malocclusion.
  30. 30. The Concorde Face Bow In the early years of Twin Blocks, tubes were added to clasp for extraoral traction on the upper appliance to be worn at night so as to reinforce the functional component for correction of a Class II buccal segment relationship. It provides intermaxillary and extraoral traction to restrict maxillary growth and at the same time, encourage mandibular growth in combination with functional mandibular protrusion.
  31. 31. Concorde Face Bow
  32. 32. Correction of Class III malocclusion with fixed reverse twin blocks in deciduous dentition • It makes easier to correct the malocclusion at early stage. • Patient compliance need is eliminated • Appliance, working whole day long, reduces the treatment time.
  33. 33. Adult Treatment • Tooth movements are slower in older patients and the skeletal response diminishes with patients age. • In adult orthodontic treatment we should anticipate a dentoalveolar response with limited skeletal adaptation, this still leaves scope for significant facial changes, but only when the skeletal discrepancy is not severe. • Surgical correction should be considered for cases of severe skeletal discrepancies in adults.
  34. 34. REFERENCES • • • • • • • • Twin block functional therapy, applications in dentofacial Orthopaedics ….William J Clark. Dentofacial orthopaedics with functional appliances ….Graber, Rakosi Petrovic Twin block technique, a functional orthopaedic appliance system AJO-DO 1988, (jan 1-18) –Clark. The action of three types of functional appliances on the activity of masticatory muscles AJO-DO 1997, (Nov 560-572) Darendeliler MA, Joho JP, MAGNETIC ACTIVATOR DEVICE (MAD II) for correction of Class II div 1 malocclusion ( JCO 103, 223-229)
  35. 35. Thank you For more details please visit