Myofunctional appliances

utilize the growth spurts of the child

1. MYOFUNCTIONAL APPLIANCES parminder kaur MDs

2. INTRODUCTION Functional appliances are used in orthodontics to modify or camouflage an underlying skeletal discrepancy. Passive appliances harness natural forces of the oro -facial musculature that are transmitted to the teeth and alveolar bone through the medium of the appliance. Basis of functional treatment is based on principle that a ‘new pattern of function’ dictated by the appliance , leads to the development of corresponding ‘new morphologic pattern’

3. Functional appliances are conceptually based on Moss’ functional matrix theory. Functional matrix theory proposes that functional matrices, tissues like muscles and glands influence skeletal units such as jaw bones and ultimately control their growth .

4. History W.K. Bridgam -1859, causes of irregular teeth is unbalanced muscle pressure. Kingsley -1880, introduced the concept of ‘jumping the bite’ in patients with mandibular retrusion. Pierre robin-1902, introduced monobloc , used to position the mandible forward in patients with mandibular retrognathism Herbst-1909, invented the first fixed functional appliances that subjected the mandible to constant forced protrusion.

5. Alfred Paul rogers-1918, concept of ‘ myofunctional therapy’ to the American Society of orthodontist. William clark -1977,Twin Block appliance’. Rapid functional correction of malocclusion transmission of favorable occlusal forces to occlusal inclined plane that cover the posterior teeth.

6. How do they work .. Activation of the muscles of mastication Dental changes- Guided eruption of teeth Changes in incisal inclination Tonal balance of the buccal and lingual musculature Modification of the soft tissue activity Bone growth

7. Potential advantages Enlarge transverse width of arches to relieve crowding. Diminsh adverse fixed appliances problems Reduced or eliminate dysfunctional habits Treatment of temporomandibular disorders

8. Indications Well aligned dental arches Posterior positioned mandible Non severe skeletal discrepancy Lingual tipping of mandibular incisors Proper patient selection

9. Contraindications Class II skeletal by maxillary prognathism Vertically directed grower Labial tipping of lower incisors Severe crowding

10. MAXIMIZING THE SUCCESS OF MYOFUNCTIONAL APPLIANCES mild/moderate skeletal problems Patient and family cooporation Patient actively growing Growth spurt for boys(12-14) for girls(11-13)

11. CASE SELECTION Suited to treat Class II, division 1 malocclusion- Age : growing patient (b/w 10 yrs & pubertal growth phase). Social considerations: Results with minimum supervision. Patients who live far away from clinic may benefit from these appliances. Dental considerations: Only the case devoid of gross local irregularities like rotations and crowding. Low angle cases – respond well

12. High angle cases with Increased overbite are successfully treated High angle cases with an open bite pose special problems Class II , div 2 is usually first modified to a div 1 and then treated. Mild class III malocclusions, which present with a reverse overjet can also be considered.

13. CEPHALOMETRIC ANALYSIS This includes three angular measurements Saddle angle Articular angle Gonial angle And four linear measurements -anterior and posterior facial height. -anterior and posterior cranial base length.

14. Saddle Angle N-S- Ar A large saddle angle signifies posterior condylar position and a mandible which is posteriorly placed with respect to cranial base and maxilla. Posterior positioning of the fossa is some times compensated by the articular angle and ramal length. A non compensated posterior positioning of mandible caused by a large saddle angle is difficult to influence with functional therapy.

15. Articular angle S- Ar -Go A decrease in the articular angle can be seen in - Anterior positioning of the mandible -Mesial migration of posterior segment An increase in the articular angle is seen in: -Posterior relocation of mandible -Distal driving of posterior teeth.

16. Gonial angle AR-Go-Me An angle formed by tangents to the body of the mandible and posterior body of the ramus. Acute or small angle ,signifies the horizontal growth direction. condition favorable for functional appliance therapy/anterior positioning of mandible

17. Anterior and Posterior facial height These are linear metric measurements -Anterior facial height— nasion to menton -Posterior facial height— sella to gonion

18. Jarabak’s Ratio It gives an idea about the growth direction of the patient. Jarabak’s ratio = PFH ----- X 100 AFH <62% indicates vertical growth pattern. > 65% indicates more horizontal pattern of growth

19. Visual Treatment Objective Important diagnostic test undertaken before making a decision to use a functional appliances. Performed by asking the patient to bring the mandible forward An improvement in profile is considered a positive indication for the use of functional appliances

20. Classification- Based on transmission of force Group I appliance - transmit muscle force directly to the teeth. e.g. inclined plane, oral screen. Group II appliance - reposition the mandible downward and forward (except in class III malocclusion), activating the attached and associated vasculature. e.g. Activator. Group III appliance - bring mandibular changes through musculature only. Their major operating area is in the vestibule outside the dental arches. Supporting bone and teeth are influenced by changing the muscle balance through cheek shields and lip pads. e.g. Frankel FR.

21. By Proffit - Tooth borne active appliances : modifications of activator and bionator designs that include expansion screws or springs to move teeth. e.g. Expansion activator, Orthopaedic corrector. Tooth borne passive appliances . These appliances have no intrinsic force generating capacity from springs or screws and depend only on soft tissue stretch and usual activity to produce treatment effects e.g. activator, bionater . Tissue borne appliance . The appliance has minimal contact with teeth and is located in vestibule. e.g. Functional regulator.

22. Myotonic Appliance -These appliance depend on muscle mass for their action. Myodynamic appliances - These appliances depend on muscle activity for their action. Removable Functional Appliances - can be removed and inserted into mouth by patient. Fixed functional appliances - cannot be removed by the patient

23. Treatment Principles Force application : Primary alteration in form with a secondary adaptation in function. Force elimination : Elimination of abnormal and restrictive environmental influences on the dentition.

24. Functional component Bite Planes Shields Or Screens Construction Or Working Bite BITE PLANES Flat or Inclined Anterior or Posterior Contacting Single or Multiple Teeth

25. FLAT ANTERIOR BITE PLANE- It should be of sufficient dimensions to disocclude the posterior teeth . Following effects are seen:- Differential eruption of posterior teeth. Non eruption, relative or absolute intrusion of incisors. Incisor overbite reduction Dis-occlusion with removal of intercuspation may will be responsible for any additional increments of mandibular growth. Unimpeded posterior tooth eruption may result in a downward and backward mandibular rotation that tends to increase anterior vertical lower height and reduces the prognathism of the mandible.

26. FUNCTIONAL APPLIANCES ADVANTAGES :- Elimination of abnormal muscle function . Treatment can be initiated at early age . Psychological disturbances avoided . Less chair side time. Frequency of patient visit is reduced . Worn during night so good patient acceptance . LIMITATIONS- Cannot be used in adult patients . Cannot be used to bring about individual tooth movement . Patient cooperation is required . Pre-functional orthodontic tooth movement is required . Fixed appliance therapy may be required.

27. Vestibular Screen Takes form of a curved shield of acrylic placed in the labial vestibule. Introduced by Newell in 1912. Principle: Both force application and elimination. Indications : Habits interception. Mild distocclusions . To perform muscle exercises. To correct mild anterior proclination

28. MANAGEMENT AND MODIFICATIONS To be worn during night and 2-3 hours during daytime. Patient is instructed to maintain lip seal. Modifications include : Hotz modification Double oral screen Kraus’s modification .

29. Lip Bumper MODE OF ACTION Holding the muscles and soft tissue away from the teeth Shields are placed up to 3 mm away from the teeth EFFECTS By reducing the pressure of the lips and cheeks on the teeth, the tongue applies an uncompensated lingual force on the teeth resulting in distal molar crown tipping, slight expansion of the buccal segments, and incisor proclination .  

30. Activator INDICATIONS Class II, div 1 Class II, div 2 Class III malocclusion Class I open bite Class I deep bite. CONTRA INDICATIONS C lass I problems of crowded teeth. Excessive lower facial height In non growing individuals.

31. MECHANISM OF ACTION

32. CONSTRUCTION BITE B ite opening - 2-3 mm advancement - 4-5 mm. O verjet is too large, forward positioning is done - 2-3 stages In case of forward positioning of the mandible by 7-8 mm, the vertical opening should be slight to moderate i.e. 2-4 mm. If the forward positioning is not more than 3-5 mm then the vertical opening can be 4-6 mm.

33. FABRICATION OF ACTIVATOR Impression making Study & working models preparation Bite registration Articulation of the model Preparation of wire elements Fabrication of the acrylic portion 3 parts: Maxillary part Mandibular part Inter occlusal part

34. Management Wear time: 2-3 hours a day during first week. Second week 3 hrs during day and during sleeping. Trimming plan is developed on the basis of individual needs of the patient. In expansion treatment the jackscrew are normally activated by the patients at 1-week interval. Check the screw Recall every 6 weeks

35. Trimming V ertical control   For dolichofacial patients: intrude molars, extrude incisors For brachifacial patients: intrude incisors, extrude molars

36. MODIFICATION OF ACTIVATOR

37. BIONATOR Developed by Balters in 1950’s. Modified activator less bulky & more Elastic 3 types- Standard type-class II div I having narrow dental arches Class III Appliance Open bite appliance

38. FRANKEL FUNCTIONAL REGULATOR developed by Rolf Frankel Frankel believed that the active muscle and tissue mass i.e ., the buccinator mechanism and the orbicularis oris complex have a major role in the development of skeletal and dentofacial deformities .

39. TYPES OF FUNCTIONAL REGULATOR 1 . FR l-used for Class I and Class II, Division 1. FR la -used for Class I ,moderate crowding and deep bite. FR lB -used for Class II Division 1 overjet less than7mm. FR lc -used for Class II Division 1 overjet more than7mm 2. FR Il-used for Class II Division 2 and Division 1 3 . FR Ill-used for Class III 4 . FR IV-used for cases with open bite and bimaxillary protrusion. 5. FR V-FR with headgear.

40. FRANKEL REGULATOR-II Promotes transverse and vertical development of maxillary and mandibular arches , corrects Class II, Division 2 cases and opens bite. Used after the maxillary incisors have been slightly proclinated by an upper removable appliances

41. TREATMENT TIMING late mixed and transitional dentition period, when both the soft and hard tissues are undergoing their greatest transitional changes. Treatment for Class III and open bite cases should usually start sooner than for Class Il problems.

42. MODE OF ACTION OF FR-II Increase in transverse sagittal direction by use of buccal shields and lip pads. 2. Increase in vertical direction by allowing the lower molar to erupt freely because appliance is fixed to the upper arch. 3. Muscle adaptation The form and extension of the buccal shields and lip pads along with the prescribed excercises corrects the abnormal peri -oral muscle activity.

43. ORAL EXERCISES WITH FRANKEL Frankel-full time wear appliance . Lips to be closed at all times or keep a paper between the lips. Swallowing , speaking, etc . with the appliance in mouth , itself serves as an exercise .

44. WEAR TIME First few weeks: 2-4 hours/day (day time) After 3 weeks : 4-6 hours/day (day time) After 3 rd visit (2 months) : full time wear. The patient is asked to perform oral gymnastics i.e. talking , reading, tightly grasping the appliance in the vestibule

45. TWIN BLOCK U sed to help correct jaw alignment, particularly an underdeveloped lower jaw . Dr.William J. Clarks , 1977 . Consists of u/l plates having occlusally inclined planes that induce favorably directed occlusal forces by causing a functional mandibular displacement.

46. MODE OF ACTION Twin blocks are simple bite blocks designed for full time wear. U pper and lower bite blocks interlock at a 70 degree angle. Twin blocks achieve rapid functional correction of malocclusion by modifying the occlusal inclined plane,guiding the mandible forward into correct occlusion. The forces of occlusion are used to correct the malocclusion.

47. MUSCLE RESPONSE C hanges in the muscles activity (1-7 days) D ecreased in activity of temporalis muscles increased activity of masseter and lateral pterygoid (3 weeks) cycles of changes was completed (3 months)

48. PHASES OF TREATMENT Active phase -Average time of treatment 6-9 months to achieve full reduction of overjet to a normal incisors relationship and to correct the distal occlusion . Support phase -3 to 6 months for molars to erupt into occlusion and premolars to erupt after trimming the blocks. The objective is to support the corrected mandibular translation while buccal teeth settle into occlusion . Retention- 9 months , reducing appliance wear when the position is stabilized. An average estimate of treatment time is 18 months , including retention.

49. TWIN BLOCK SAGITTAL APPLIANCE Used to treat class II div 2 malocclusion. Sagittal arch development is necessary to increase arch length and to advanced retroclined incisors.

50. REVERSE TWIN BLOCK C orrection of class III malocclusion By reversing the occlusal inclined planes to apply a forward component of force to the upper arch and a downward and backward force to lower arch .

51. MAGNETIC TWIN BLOCKS Magnets are incorporated in occlusal inclined plane. Purpose of magnets is to increased occlusal contacts on the bite blocks to maximize the favorable functional forces applied to correct the malooclusion .

52. FIXED TWIN BLOCK

53. Advantages very good patient acceptance . bite planes offer greater freedom of movement & lateral excursion . less interference with normal function . significant changes in patient’s appearance within 2-3 months.

54. HERBEST APPLIANCES JASPER JUMPER THE MANDIBULAR ANTERIOR REPOSITIONING APPLIANCE ( MARA ) EUREKA SPRING SABBAGH UNIVERSAL SPRING FIXED FUNCTIONAL APPLIANCES

55. HERBEST APPLIANCE Indications 1- dental CII 2- skeletal CII due to mandibular deficiency 3- deep bite with retroclined mandibular incisors . Contra indication 1-Open bite 2-vertical grower Disadvantages • Appliance is prone to breakage . • Lateral movement is restricted

56. JASPER JUMPER Indications • Dental Class II malocclusion • Deep bite with retroclined mandibular incisors . Contraindications • Dental and skeletal open bites . • Minimum buccal vestibular space . • Vertical growth pattern with increased lower facial height . -Cases prone to root resorption

57. JASPER JUMPER Advantages - Ease of insertion and activation - Generation of intrusive forces on molars and incisors. Disadvantages - Frequent breakages - Compromised oral hygiene - Externally bulge in the cheeks

58. MANDIBULAR ANTERIOR POSITIONING APPLIANCES (MARA) Indication -Skeletal Class II with mandibular deficiency . Contraindications -Cases prone to root resorption Dental and skeletal open bite -Vertical growth pattern.

59. EUREKA SPRING Advantages - Good patient acceptance - Can be used for Class Il and Class ill - Components are available separately - Significantly less expensive Disadvantages -Technique sensitive insertion procedure - Frequent breakages of interval spring - Less force levels than twin force corrector .

60. SABBAGH UNIVERSAL SPRING It is the latest inter arch compressive spring to be introduced and has a number of unique features . • Available in one standard link. - No difference in appliance for the right and left sides . - Lateral mandibular movement possible . - More resistant to fatigue fracture

61. SABBAGH UNIVERSAL SPRING The SUS is a combination between the Herbst appliance (as a telescope) and the Jasper Jumper (as a spring) aiming to increase the efficacy of th treatment and to minimize their disadvantages. INDICATIONS- •Class II, late growth cases (rapid class II correction ) •Non-compliant class II patients •TMD therapy

62. SABBAGH UNIVERSAL SPRING ADVANTAGES Dentoalveolar changes :- - distal movement of the upper molars - mesial movement of the lower molars - retrusion of the upper incisors - protrusion of the lower incisors DISADVANTAGES - Unsuitability for Class Ill treatment - Limitations in patients with maximum opening of less than 48 mm. - Increased force levels - Considerably greater cost

63. CONCLUSION The method chosen depends upon on a series of factors that must be carefully evaluated before the therapy is instituted. The developmental age of the patient Location and etiology of malocclusion The specific morphological characteristics in both skeletal and dental arches The motivation and likely continuing co-operation of both the patient and the patient’s parents. No universal appliance or formula is available for any malocclusion. Only a careful diagnosis, a continuing diagnostic monitoring during treatment, a number of appliances in the armamentarium, and a willingness to change appliances as changing situations dictate will ensure the best possible treatment