Mode of action of functional appliances /certified fixed orthodontic courses by Indian dental academy


Published on

The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit ,or call

  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Mode of action of functional appliances /certified fixed orthodontic courses by Indian dental academy

  1. 1. MODE OF ACTION OF FUNCTIONAL APPLIANCES INDIAN DENTAL ACADEMY Leader in continuing dental education m
  2. 2. Introduction:  Correction of malocclusion, primarily by means of controlled movement of the developing and mature dentition into a desirable occlusal relationship  Control and modification of growth of skeletal structures of the craniofacial complex, especially via tooth borne appliances m
  3. 3. Historical perspective:  Genetic control theory: -inheritance and immutability of normal and abnormal facial form - genotype supplies all information required for phenotypic expression m
  4. 4. Historical perspective: Late 1890s: Wolff’s law and Roux hypothesis: changes in functional stress produced changes in internal bone architecture and external shape  Early 1900s: Pierre Robin: monobloc - passive positioning device  Modified from bite jumping vulcanite maxillary guide planes designed by Norman Kingsley (1880)  Vorbissplatte: Hotz  m
  5. 5. Historical perspective: Viggo Andresen : Activator  Lischer’s theory: If abnormal musculature can exacerbate existing malocclusions, can not the same muscles be used to correct these problems?  Andresen: modified Hawley type retainer with lower lingual horse shoe flange Significant sagittal basal bone and neuromuscular improvement  m
  6. 6. Historical perspective:  Initially not accepted in US: - facial growth could not be affected - tooth position can be altered with appropriate appliances and biomechanics m
  7. 7. Theories of growth:  Genetic theory  Sutural growth theory: Sicher (1947): growth at the sutures results in growth of cranial vault and downward and forward growth of the midface Cartilage- directed growth theory: Scott (1956): synchondroses, nasal septum and mandibular condyle are centers of growth  m
  8. 8. Theories of growth: Functional matrix hypothesis: Melvin Moss (1960)   Craniofacial skeleton develops initially and grows in direct response to its extrinsic, epigenetic environment  Functional matrix and skeletal unit  “ Bones do not grow, bones are grown.” - Moss (1972) m
  9. 9. Theories of growth:   Servosystem theory of craniofacial growth: Alexandre Petrovic (1970s) 2 factors: - hormonally regulated growth of the midface and anterior cranial base, which provides a constantly changing reference input via the occlusion - rate-limiting effect of growth of the midface on the growth of the mandible m
  10. 10. m
  11. 11. Activator: Initial appliance: passive  Loose appliance:Biting into the appliance effected the extrinsic force; worn only at night  Andresen and Haupl: altering skeletal relationship depending on the direction and amount of jaw growth incorporated in appliance ( Norwegian system)  m
  12. 12. Activator:      Activator: Andresen and Haupl Sagittal positioning of the mandible Elimination of abnormal musculature Musculoskeletal adaptation by inducing a new pattern of mandibular closure Condylar adaptation: growth in upward and backward direction to maintain integrity of TMJ structures m
  13. 13. m
  14. 14. Activator:     Stimulation of myotactic reflex activity, causing isometric muscle contractions Loose fit of appliance with low vertical dimension Muscle force transmitted onto teeth: uses kinetic energy Increased activity of elevator and protractor muscles with relaxing and stretching of retractors m
  15. 15. Activator: Other views:  Muscle contraction: superior head of lateral pterygoid muscle - Petrovic (rat studies), McNamara (primate studies) - variations in the mode and direction of dislocation of mandible  Condylar unloading: Lysle Johnston m
  16. 16. Activator: Viscoelastic activity: Herren(1953), Woodside(1973), Harvold(1974  Viscoelastic reaction: - emptying of vessels - Pressing out of interstitial fluid - Stretching of fibres - Elastic deformation of bone - Bioplastic adaptation  m
  17. 17. Activator:      Herren: anterior crossbite relationship Woodside: 10- 15 mm. Beyond postural rest vertical dimension Opening of 4-6 mm: Eschler(1952) no overcompensation Transitional type of activator action Uses isometric and isotonic contractions m
  18. 18. Activator: Head posture during sleep: Changes of head posture alter the magnitude and direction of force  Change in mandibular position varies force vectors acting on mandible and different muscle groups  Plane of sleep( light or deep), intraoral air pressure, dream cycle, state of mind also affects activator response during sleep  m
  19. 19. Activator:  Skeletal effects: - movement of condle in forward and downward position due to the appliance - adaptation to the new position through condylar growth; growth in more backward and upward direction - adaptation to new position through fossa remodeling - more posterior orientation of trabaculae m
  20. 20. m
  21. 21. Activator:  Dental effects: - forward displacement of lower anterior segment (Bjork,1969) - bodily displacement of incisors (Jacobsson, 1967) - labial tipping of lower incisors (Richardson,1982) - lingual tipping (Moss, 1962) m
  22. 22. Activator:  Types of force employed in activator therapy: - sagittal: mandible downward and forwardmuscle force to condyle and slight reciprocal force to maxilla - vertical: teeth and alveolar processes are either loaded or relieved of normal forces ; high construction bite inhibits growth, direction and inclination of maxillary base - transverse: incorporation of screws and springs; midline correction m
  23. 23. Bionator: Balters (1943)  Equilibrium between tongue and circumoral muscles infleunces shape of dental arches and intercuspation  Tongue is the center of reflex activity in the oral cavity  m
  24. 24. m
  25. 25. Bionator: Position of the tongue: posterior displacement: class II low anterior displacement: class III narrow arches and crowding: low outward pressure open bite: hyperactivity and forward posture  m
  26. 26. Bionator:  Forward posturing of mandible: - enlargement of oral space - dorsum of tongue contacting soft palate - accomplish lip closure m
  27. 27. Bionator: Effects:  Modulation of muscle activity of tongue  elimination of abnormal influences of perioral musculature  Stimulation of myotactic muscle activity and isotonic muscle contractions m
  28. 28. Bionator: Effects:  No vertical component except for guiding eruption of teeth  No viscoelastic response  Prevention of deleterious parafunctional activity at night : relaxation of lateral pterygoid ( used for TMJ problems) m
  29. 29. Frankel function regulator: Frankel philosophy:  Potential restraining influence of the active muscle and tissue mass of the buccinator mechanism and the orbicularis oris complex  Artificial matrix allowing the muscles to exercise and adapt m
  30. 30. m
  31. 31. m
  32. 32. Frankel function regulator:     Exercise device: stimulates normal function, eliminating the lip trap, hyperactive mentalis, aberrant orbicularis oris and buccinator Negative pressure of the muscles during deglutition is prevented Bodily buccal movement of posterior teeth Oral gymnastics: lip seal exercises m
  33. 33. Frankel function regulator: Periosteal pull of buccal shields and lip pads increases bone activity  Stimulation of mid palatal suture growth lesser extent increasing bone apposition on the external subperiosteal layer of maxilla ( Stutzmann et al 1983, Graber et al 1991)  m
  34. 34. m
  35. 35. Frankel function regulator: Dental effects:  Appliance anchored to maxillary arch; allows more downward and outward movement of upper teeth  Lower posterior teeth are allowed to erupt upward and forward; sagittal and vertical correction m
  36. 36. Twin block:       Clark ,1977 Modification of occlusal inclined planes by means of acrylic inclined planes on bite blocks Guide mandible downward and forward Favorable proprioceptive contacts of inclined planes Adaptation of the muscles of mastication Vertical and transverse control m
  37. 37. m
  38. 38. Twin block: Mode of action:  McNamara(1980)  Rapid neuromuscular response  Gradual dentoalveolar response  Pterygoid response: pain while retracting the mandible m
  39. 39. Twin block: Proliferation of connective tissue and blood vessels in the retrodiscal area  Johnston( 1976) unloading of the condyle  Discomfort on removal of appliance due to compression in the tension zone behind the condyle  m
  40. 40. Functional appliances and extraoral force:     Class II div 1 with excessive vertical growth Unloading of the condyle by forward posture of mandible Retardation of horizontal and vertical maxillary growth by headgear Margolis ACCO(1976); Jacobsson splint (1967); Stockli and Teuscher activatorheadgear combination m
  41. 41. Fixed functional appliances: Herbst, 1909- Scharnier  Mandible was kept forward continuously, eliminating the need for patient compliance  Herbst and Schwartz, 1934  Pancherz, 1979  m
  42. 42. m
  43. 43. Fixed functional appliances: Sagittal changes:  Restraint of maxillary growth: headgear like effect  Stimulation of mandibular growth: - remodeling on lower border of mandible(Pancherz and Ruf,1997) - modification of TMJ fossa( Paulsen,1997; Buschang,1998) - ultimate condylar position in fossa is unaffected m
  44. 44. Fixed functional appliances: Sagittal changes:  Proclination of lower incisors  Posterior movement of upper molars: headgear like effect m
  45. 45. Fixed functional appliances: Vertical changes:  Eruption of lower molars; intrusion of lower incisors: reduction of overbite  Proclination of lower incisors contributing to overbite reduction m
  46. 46. m
  47. 47. Fixed functional appliances: Long term changes:  Class I relationship is maintained with stable cuspal interdigitation  Causes of relapse: - too early treatment - mixed dentition treatment - persistent abnormal musculature - unstable post treatment occlusion - insufficient length of appliance wear and retention m
  48. 48. Fixed functional appliances: Soft tissue changes:  Reduction of soft tissue convexity, excluding the nose  Increase in soft tissue convexity, including the nose, because of normal nasal growth  Retrusion of upper and lower lips in relation to esthetic line due to normal chin and nose growth m
  49. 49. Fixed functional appliances: Jasper jumper:  James Jasper, 1987  Effects: - functional effect similar to Herbst appliance - dentoalveolar changes m
  50. 50. m
  51. 51. Fixed functional appliances: Repositioning effect:  Farrar effect: reciprocal clicking  Recapturing of the disc  Repositioning of condyle  Maintaining the repositioning effect  Orthodontic occlusal correction in the desired position  m
  52. 52. m
  53. 53. Mode of action: Condylar growth:  Forward positioning of mandible  Increased activity of LPM  Intensification of repetitive activity of retrodiscal pad m
  54. 54. Mode of action:  1. 2. - Condylar growth: increase in growth stimulating factors: enhancement of local mediators Reduction of local regulators change in condylar trabacular orientation additional growth of condylar cartilage additional subperiosteal ossification of posterior border of mandible lengthening of mandible m
  55. 55. Mode of action:   1. Increased activity of LPM Retrodiscal pad- mediator of response Blood circulating effect: - increase in blood and lymph flow, - increase in nutritive and growth stimulating factor supply ( STH-somatomedin, testosterone and estrogen in low doses, insulin, prostaglandin F2, mitogenic peptides) m
  56. 56. Mode of action: - decrease in locally produced catabolites and other negative feedback factors ( prechondroblast’s multiplication restraining signal, cAMP, prostaglandin E2, somatostatin-like substance) - iterative action m
  57. 57. Mode of action: 2. Biomechanic effect: - Accentuated concavity at the posterior border of mandibular ramus due to increase in condylar growth and more posterior directed growth - piezoelectric effect: increase in negative charges along posterior border, causing increased periosteal bone formation and vice versa - supplementary lengthening of mandible m
  58. 58. m
  59. 59. Herren and LSU activator:  Bite opened well beyond postural rest position  Forward positioning of mandible leads to reduced increase in length of LPM  Sensory engram formed for new position of mandible  Functioning of mandible in more forward position when appliance is not worn  Increased activity of retrodiscal pad with acceleration of condylar growth m
  60. 60. Growth restriction of glenoid fossa: normal growth of glenoid fossa is in posterior and inferior direction Anterior slope of articular eminence undergoes bone deposition on posterior slope and resorption on anterior slope Anterior relocation of glenoid fossa in orthopedic treatment Reciprocal forces from viscoelastic tissue between condyle and fossa  m
  61. 61. Growth relativity hypothesis: Voudoris, Kuftinec AJODO March 2002  Mandibular advancement  Fibrocartilagenous lining in glenoid fossa induces bone formation locally  Stretch of nonmuscular viscoelastic tissues  New bone formation some distance from the actual retrodiscal attachments in the fossa m
  62. 62. m
  63. 63. m
  64. 64. Growth relativity hypothesis:  Fibrocartilage caps the condyle in 3 dimensions: posterior, anterior and 2 collateral along with fibrous capsule and synovial fluid  Advancement: engorgement of blood vessels, influx of nutrients and biodynamic factors  Reseating of condyle in fossa: expulsion of these factors  Resulting metabolic pump-like action m
  65. 65. m
  66. 66. Growth relativity hypothesis:  Disoccluding appliances cause low intraarticular subatmospheric pressures within TMJ in open position ( Nitzan, 1994)  Shift of synovial fluid perfusion on a posteriorly displaced direction  Negative pressures are below capillary perfusion pressure  Greater flow of blood to the region m
  67. 67. Growth relativity hypothesis: Bone architecture is influenced by the neuromusculature and the contiguous nonmuscular, viscoelastic tissues anchored to the glenoid fossa and the altered dynamics of the fluids enveloping bone m
  68. 68. Displacement+ viscosity+ referred force  1. 2. 3. Three growth stimuli: Anterior orthopedic displacement Posterior viscoelastic tissues between condyle and fossa Transduction of forces over the fibrocartilage cap of the condylar head, increases radiating endochondral bone formation beneath condylar fibrocartilage and periosteal bone formation in the fossa m
  69. 69. m
  70. 70. m
  71. 71. Condylar light bulb analogy: Condyle acts like a light bulb on a dimmer switch  Lights up during advancement, dimming back to near normal levels during retention  Growth potential diminishes with age while remodeling potential last long into adulthood  m
  72. 72. m
  73. 73. m
  74. 74. Clinical implications: Prevention of condylar compression by using Herbst with thin posterior bite blocks  Rapid maxillary expander to reduce occlusal interferences and functional shifts due to the anterior positioned mandible  m
  75. 75. Studies on functional appliances: Activator:  Charlier et al 1968, 1969, Petrovic et al 1975: Distribution of dividing cells in sagittal section of condylar cartilage of juvenile rats  Histologic and radiographic study  Results: Treatment with both postural hyperpropulsor and and growth hormone STH produced increase in growth rate of condylar cartilage as compared to controls m
  76. 76. Studies on functional appliances: Activator:  Location of increase of dividing cells: - more posterior in hyperpropulsor - more anterior in STH m
  77. 77. m
  78. 78. Histologic study: - growth of bony trabaculae formed in parallel and posteriorly oriented condylar cartilage m
  79. 79. Studies on functional appliances: Activator:  Petrovic and Stutzmann (1977), rat experiment  Administration of growth hormone and treatment by postural hyperpropulsor: - increase in condylar cartilage growth rate - hyperpropulsor: opening of Stutzmann angle - growth hormone: closing of Stutzmann angle m
  80. 80. Studies on functional appliances: Activator: - lengthening of mandible measured from posterior edge of condylar cartilage to mental foramen is greater in case of opening of angle  Administration of testosterone: male rats for 3 weeks; stimulation in growth rate of condylar cartilage and lengthening of mandible (Stutzmann 1976, Petrovic, Stutzmann 1977, 1978) m
  81. 81. m
  82. 82. Studies on functional appliances: Activator:  Resection of lateral pterygoid muscle: decrease in condylar growth rate and lengthening of mandible ( Petrovic, Stutzmann 1972, 1974); opening of Stutzmann angle  Effect of postural hyperpropulsor: greater the sagittal advancement, greater the condylar cartilage growth rate and mandibular lengthening, opening of angle; decreases with time m
  83. 83. Studies on functional appliances: Activator:  Growth rotation and alveolar bone turnover of mandible: high alveolar turnover rate with anterior growth rotation than posterior rotation m
  84. 84. Studies on functional appliances:  Woodside et al 1975: - effect of activator treatment applied during the evening and night on mandibular length - periods of treatment were not coincident with mandibular growth accelerations (except in 1 case) - therefore, treatment with functional appliances should be started coincident with naturally occurring mandibular growth accelerations m
  85. 85. Studies on functional appliances:  Altuna, Woodside 1977, 1985: - primate experiments using juvenile and adult animals in which mandible was opened 2, 4, 8, 12 mm. Without sagittal advancement - openings greater than 2mm resulted in increased mandibular length due to changes in condylar stress m
  86. 86. Studies on functional appliances:  Woodside 1985: EMG activity in LPM by Frankel functional regulator and activator - both appliances generated similar amounts of LPM activity after initial appliance insertion m
  87. 87. m
  88. 88. Studies on functional appliances:    Woodside et al 1987: assessment of remodeling changes in the glenoid fossa using juvenile monkeys - Herbst appliance with progressive activations used - extensive remodeling and anterior relocation of glenoid fossa seen Voudoris 1988: same changes Angelopoulos 1991: changes in glenoid fossa remodeling are stable m
  89. 89. Studies on functional appliances:  Sessle et al 1990: longitudinal effect of functional appliances on jaw muscle activity using 6 female monkeys - pre appliance and post appliance levels compared with controls - Herbst and functional protrusive appliances inserted - decreased activity in superior and inferior head of LPM, superficial masseter, anterior digastric; persisted for 6 weeks returning to previous levels after 6 week observation period m
  90. 90. Studies on functional appliances:  McNamara 1972, 1973: cephalometric, electromyographic and histologic study of altered functional position of lower jaw in monkeys - increased activity of superficial head of masseter, decreases activity of posterior part of temporal muscle, increased activity of superior head of LPM m
  91. 91. m
  92. 92. Studies on functional appliances:  Elgoyhen, McNamara et al, 1972: advancement of mandible of 6 juvenile monkeys for 5 months - significant increase in rate of growth of condyle - rate increased with increased time of appliance wear; within 3 months with peak in 2 months; reduction in 4 months m
  93. 93. Studies on functional appliances:  McNamara 1973, 1974: vertical dimension was increased by using cast gold inlays opening bite from 2 to 15 mm in incisor region in monkeys - contraction of superior head of LPM - elongation of elevator muscles - gradual change - inhibition of normal downward and forward growth of maxilla m
  94. 94. Studies on functional appliances: Taken from the AJO-DO 1982 Oct (288-298): - McNamara, Hinton and Hoffman  Histologic analysis of temporomandibular joint adaptation to protrusive function in young adult rhesus monkeys (Macaca mulatta) - twelve young adult female rhesus monkeys were fitted with functional protrusive appliances for periods ranging from 2 to 24 weeks.  m
  95. 95. Studies on functional appliances: - a proliferative chondrogenic response accompanied by deposition of new bony trabeculae at the bone-cartilage interface, though greatly reduced in magnitude as compared to juvenile monkeys m
  96. 96. Studies on functional appliances:  Taken from the AJO-DO 1987 Mar (213-224): - DeVincenzo, Huffer, and Winn - A study in human subjects using a new device designed to mimic the protrusive functional appliances used previously in monkeys - maxillary and mandibular posterior biteplates separated by a sharp vertical interface perpendicular to the occlusal plane m
  97. 97. Studies on functional appliances:  -The rate of mandibular length increase in the treatment group over that of controls was comparable to values reported in monkeys. Other skeletal and dentoalveolar changes were likewise similar to those found in monkeys. m
  98. 98. m
  99. 99. Studies on functional appliances: Bionator:  Taken from the AJO-DO 1990 Feb (113-120): Mandibular response to orthodontic treatment with the Bionator appliance - Mamandras and Allen - A group of 20 subjects who underwent successful Bionator treatment was compared with 20 subjects who were treated less successfully with the same appliance. Both groups had similar advancements in their bite registrations, as well as similar treatment times and growth-prediction parameters m
  100. 100. Studies on functional appliances: Bionator: - both the total mandibular length and the horizontal mandibular dimensions in the large-advancement group was greater than that in the small-advancement group. Only the vertical mandibular dimension remained slightly, but not significantly, reduced when compared with the small-advancement group - more distal posttreatment condylar position in the large-advancement group as compared with the small-advancement group m
  101. 101. Studies on functional appliances: Frankel appliance:  Taken from the AJO-DO 1989 Oct (333341): - Falck and Fränkel  Clinical relevance of step-by-step mandibular advancement in the treatment of mandibular retrusion using the Fränkel appliance  120 pts: 60 with end on relationship, 60 with step wise advancement m
  102. 102. Studies on functional appliances: Frankel appliance: - better sagittal correction with gr. B - opening of mandibular plane angle in gr. A - more dentoalveolar changes with gr.A - condyle in more anterior position in gr. A - gr. A had better restraining effect on maxilla (point A and maxillary molar) m
  103. 103. Studies on functional appliances: Taken from the AJO-DO 1982 Jul (1022): Arch width development in Class II patients treated with Fränkel appliance - McDougall, McNamara, and Dierkes  60 treated with FR 1 and 2 and 47 untreated cases  changes in lingual, buccal, and alveolar arch widths were compared.  m
  104. 104. Studies on functional appliances: expansion of the maxillary and mandibular dental arches and their supporting structure occurs routinely with a functional regulator (FR-1 or FR2)  largest expansion in the premolar and molar regions, lesser in the canine region; in the maxilla narrower arches tend to expand more than wider arches  m
  105. 105. Studies on functional appliances: Taken from the AJO-DO 1990 Aug (134-144): Comparison of Herbst and Frankel appliances - McNamara, Howe, and Dischinger  A comparison of the Herbst and Fränkel appliances in the treatment of Class II malocclusion - 45 pts with acrylic splint Herbst and 41 pts with FR2 - cephs compared with 21 untreated class II pts  m
  106. 106. Studies on functional appliances: - Significant skeletal changes were noted in both treatment groups, with both groups showing an increase in mandibular length and in lower facial height, as compared with controls. - Greater dentoalveolar treatment effects were noted in the group wearing the toothborne functional appliance than in those wearing the tissue-borne appliance. m
  107. 107. Proffit, Tulloch AJODO,June 2002 Optimal timing of treatment for Class II malocclusion  - can jaw growth really be modified, by how much, with what predictability, in which patients? - do different appliances produce different effects? - would early intervention make later treatment simpler and with better treatment results?  m
  108. 108. Proffit, Tulloch AJODO,June 2002 Methods:  Children with overjet> 7mm, in mixed dentition, at least 1 yr before peak height velocity, excluding children with extreme vertical disproportions  2 phases: 1. - Treatment with either a combination headgear or functional appliance - Control with no treatment until permanent dentition 2. All children were treated with fixed appliances m
  109. 109. Proffit, Tulloch AJODO,June 2002 Methods:  Boys- 57.8%, girls- 42.2%  Mean age- 9.4 yrs  Mean overjet- 8.4 mm, 91% bilateral class II  175 children, 166 completed phase 1, 143 started and completed phase 2 m
  110. 110. Proffit, Tulloch AJODO,June 2002 Results:  Small mean reduction in jaw relationship with early treatment  Mechanism of change: - headgear group: restriction in fwd movement of maxilla - functional appliance: increase in mandibular length and increase in chin projection  75% of early treatment pts had highly favourable changes as compared to 25% of untreated pts m
  111. 111. Proffit, Tulloch AJODO,June 2002 Second phase:  Clinician centered outcome: change in skeletal jaw relationship or alignment and occlusion of teeth  Patient or parent oriented outcome: duration of treatment or need for extractions or other surgical procedures m
  112. 112. Proffit, Tulloch AJODO,June 2002     2 early treatment groups : reduction in ANB angle in phase 1, no sustained advantage in phase 2 No difference in patients with convex profiles No difference in quality of occlusion Early treatment did not reduce the percentage of children needing extractions in phase 2 or eventual orthognathic surgery m
  113. 113. Proffit, Tulloch AJODO,June 2002 Treatment time:  length of time in phase 2, and time spent wearing fixed appliances  Early treatment had very little effect in reducing the time of fixed treatment m
  114. 114. Proffit, Tulloch AJODO,June 2002 Discussion:  Early treatment produced an initial differential growth change  Not effective in correcting later skeletal and dental class II malocclusion  No advantage in final treatment outcome or simplification of later treatment procedures m
  115. 115. Proffit, Tulloch AJODO,June 2002 Early treatment:  Psychological distress  Accident prone children  Skeletal maturity is ahead of dental development  Children with vertical and class II problems Conclusion: no clear advantage for early treatment m
  116. 116. Thank you For more details please visit m