Functional appliance /certified fixed orthodontic courses by Indian dental academy

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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.


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Functional appliance /certified fixed orthodontic courses by Indian dental academy

  1. 1. Functional Jaw Orthopedics - Criteria for Case Selection www.indiandentalacademy.com
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  3. 3. Index I) FUNCTIONAL ANALYSIS 1. 2. 3. DETERMINATION OF NATURAL HEAD POSITION TMJ EXAMINATION ASSESSMENT OF FUNCTIONAL STATUS OF LIPS, CHEEKS AND TONGUE DYSFUNCTIONS OF THE TONGUE ASSESSMENT OF RESPIRATION PATTERN OF DEGLUTITION. 4. 5. CEPHALOMETRIC EVALUATION – – – – – CEPHALOMETRIC ANALYSIS FOR FUNTIONAL APPLIANCE PITCHFORK ANALYSIS CEPHALOMETRIC ANALYSIS FOR EVALUATING A-P DISCREPANCY OF THE JAW BASES CEPHALOMETRIC TONGUE ANALYSIS VISUALIZED TREATMENT OBJECTIVE www.indiandentalacademy.com
  4. 4. SKELETAL MATURITY INDICATORS FOR TIMING THE FUNCTIONAL APPLIANCE THERAPY • • • • • CERVICAL VERTEBRAL MATURITY INDICATOR HAND WRIST RADIOGRAPHS DENTAL CALCIFICATION FRONTAL SINUS SOMATIC MATURATION – STANDING HEIGHT AND PEAK GROWTH VELOCITY www.indiandentalacademy.com
  5. 5. Introduction • Wolff (1893) on form and function • Benninghof’s study of stress trajectories in the midface - Demonstrate the response of bone to functional forces. - Petrovic - The adaptability of the condyle to various topographic and functional www.indiandentalacademy.com relationships during the growth period
  6. 6. Functional analysis • If function is abnormal, • whether it should be altered • whether the change in forces produced can be used to help solve orthodontic problems. • If one function is changed, will it affect the other functions, which may then exert different forces on the dentofacial skeleton. www.indiandentalacademy.com
  7. 7. DIAGNOSTIC EXERCISES 1. Determination of the postural rest position of the mandible and interposed freeway space or interocclusal clearance 2. Examination of temporomandibular joint (TMJ) function or dysfunction and condylar movement in performing the stomatognathic system’s tasks 3. Assessment of the functional status of the lips, cheeks, and tongue, with particular attention to the roles they play in dentofacial abnormalities www.indiandentalacademy.com
  8. 8. • In the postural rest position, synergistic and antagonistic muscular components are in dynamic equilibrium; their balance is maintained with basic muscle tonus. • The rest position is the result of a myostatic antistretch reflex that responds only to the permanent exogenous force affecting the orofacial system (i.e., gravity). As a consequence the rest position depends on and alters with the position of the head. Thus natural head position (NHP) must be determined for each patient. • Cephalograms should be taken in NHP. www.indiandentalacademy.com
  9. 9. The movement of the mandible from postural rest to habitual occlusion is of special interest for all functional analyses. It consists of two components: • hinge (rotary) action and • translatory (sliding) movement. The objective of examination is to assess not only the magnitude and direction of these movements but also the extent of action of each hinge or sliding component. During the closing maneuver from rest position, two phases of movement can be observed • the free phase from postural rest to the point of initial or premature contact and • the articular phase from initial contact to the centric or habitual occlusal position. www.indiandentalacademy.com
  10. 10. • Functional patterns without articular phases that produce free movement from rest to full occlusal contact are seen in only a few completely balanced occlusions. A slight sliding component (as much as 2 mm), particularly in the transitional dentition, is a normal phenomenon. • If the pattern is abnormal, the sliding may be caused by neuromuscular abnormalities, disturbances in dental interrelationships, or compensation of skeletal discrepancies. www.indiandentalacademy.com
  11. 11. Assessment of the postural rest position. • Influenced by gravity • Patient seated upright (back unsupported.) • The head is oriented with the patient looking straight ahead at eye level. • Looking directly into a mirror helps establish optimal head posture www.indiandentalacademy.com
  12. 12. Command methods – wet the lips and swallow Phonetic exercises – “m” & “c” or Mississippi Noncommand methods – talk unrelated subjects & observe carefully. Combined methods –swallow & relax Clinician gently palpates the submental muscles to assess tonicity www.indiandentalacademy.com
  13. 13. Registration of the postural rest position • Direct intraoral method – Plaster core registeration but not feasible for children in the mixed dentition • Direct extraoral method – difference between distance from soft tissue nasion to menton in both postural rest and habitual occlusion. But soft tissue can mislead. • Indirect extraoral method - Reontgenography, cephalometry, electromyography, cinefluorography, and kinesiography www.indiandentalacademy.com
  14. 14. Cephalometric registration Three lateral ceph are taken • first in postural test, • second in initial contact, and • third in full habitual occlusion. Two measurements can be taken on each film. One records hinge movement of the condyle in the vertical plane. The second assesses sliding or translatory action in the sagittal plane. Comparison of the single movements permits an assessment of the path of closure of the mandible, which must be determined from rest to initial contact and initial contact to full occlusion. www.indiandentalacademy.com If a significant sliding component is observed from initial
  15. 15. Class II treatment • Posterior displacement combined with projected horizontal growth directions, the prognosis is very good. • If anterior displacement and a vertical growth vector are present, the prognosis is quite poor. • Anterior displacement +horizontal growth • Posterior displacement + vertical growth. - the prognosis is not good • It can be improved or worsened depending on the age of the patient and the specifics of the facial pattern. www.indiandentalacademy.com
  16. 16. Class III malocclusions. • Hinge-type condylar function is often associated with Class III malocclusions with straight paths of closure. • successful functional appliance treatment possible only if the magnitude of the sagittal dysplasia is moderate and therapy is begun in the early mixed dentition. • If the path of closure is up and back (an anterior postural rest position), the prognosis is even poorer. • Anterior displacement that creates an up and forward path of closure with combined rotary and translatory action of the condyle from postural rest to habitual occlusion, the prognosis is much better and treatment success is possible, even. in the www.indiandentalacademy.com permanent dentition.
  17. 17. Pseudo-forced bite • Functional therapy is the most efficient mode of treatment in the mixed dentition. But functional analysis alone is insufficient to determine prognosis because not all Class III has anterior paths of closure with good prognosis. • Sometimes a skeletal Class III relationship is partially compensated by labial tipping of the maxillary incisors and lingual tipping of the mandibular incisors. • (Diagnosis is usually possible only with the aid of cephalometric analysis). • Because of the extreme tipping possible, an anterior sliding movement into occlusion can occur • Uprighting the incisors into proper axial inclinations results in a severe Class III sagittal tooth relationship. • Orthodontic treatment is difficult as the incisors are already overcompensated before treatment. • Orthognathic surgery www.indiandentalacademy.com
  18. 18. Path of closure - Vertical plane True deep bite Pseudo deep bite Infraocclusion of the posterior segments. Normal eruption of the posterior teeth Lateral tongue posture or Over- eruption of the tongue thrust habit incisors. Large interocclusal gap Cl II div 2 with adequate lip line Small freeway space Gummy smile & poor lip line Elimination of environmental factors inhibiting eruption of the posterior teeth. Intruding incisors Distalize maxillary molars to control the vertical dimension www.indiandentalacademy.com Fnl appl is beneficial Not of much use
  19. 19. Path of closure - transverse plane • It consists of observing the behavior of the mandibular midline as the teeth are brought together from rest position to habitual occlusion. • Two functional types of crossbite. Laterocclusion - Midline shift occurs only in full occlusion but coincident in rest position. • The prognosis for functional appliance therapy is good. • Treatment requires eliminating the disturbance in the intercuspation. This often is done by widening the narrowed maxillary arch, thus improving function. The procedure also can be done in the permanent dentition • Some evidence suggest that prolonged crossbite relationships can lead to asymmetric jaw growth if allowed to continue for a number of years during the growing period - (Egermark-Ericson, Thilander). Laterognathy - Persistence of the midline shift in rest position and in occlusion. (e.g., a true asymmetric facial skeleton). • The prognosis for treatment is poor. • Successful functional appliance treatment is not possible in such cases; in severe cases, surgery is the only alternative. www.indiandentalacademy.com
  20. 20. Why should the TMJ be examined? • To identify the incipient symptoms of TMD 1. Early elimination of functional disturbances can prevent incipient TMJ problem. This is an indication for early orthodontic treatment. 2. If the temporomandibular structures are abnormal at the start and hypersensitivity is a problem, the possibility of exacerbating the symptoms exists Fortunately, this seldom happens; functional appliances often eliminate unfavorable sensory reactions in the process of posturing the mandible forward. This is an important requisite for the treatment of many adult TMJ eases. If TMJ problems are present in the deciduous dentition, forward posturing may be better achieved in a staged progression. www.indiandentalacademy.com
  21. 21. Early symptoms of TMJ problems • Clicking and crepitus • Sensitivity in the condylar region and masticatory muscles – supr head of LPM • Functional disturbances 1. hypermobility 2. limitation of movement 3. Deviation • Radiographic evidence of morphologic and positional abnormalities www.indiandentalacademy.com
  22. 22. Clicking & Crepitation • Initial – Retruded condyle in relation to disc • Intermediate – uneveness of the condylar and disc surfaces • Terminal – condyle moving too far anteriorly on opening • Reciprocal – incoordination between the displacement of condyle and disc both on opening and closing. www.indiandentalacademy.com
  23. 23. Tenderness • Tenderness to palpation condylar region in only 5.3% of the case • The most important & initial sign is tenderness of the temporalis, masseter & lateral pterygoid muscle (LPM) (though its difficult and relatively unreliable) supr head is of particular importance. www.indiandentalacademy.com
  24. 24. Functional disturbance • 50% Hypermobility - an opening of more than 45 mm in 6 to 8-yrs, more than 49 mm in 10 to 12-yrs - mostly habitual, but it can indicate a predisposition to later temporomandibular dysfunction (TMD). • In 22% an anterior displacement of the condyle over the articular tubercle occurred. • Limited movement because of muscle spasm -not a major concern. • Deviation of the opening or closing movement sagittally or transversely (24%). • In 11.5% an S opening occurred as the condyles moved forward or backward unevenly in the functional maneuvers. • Deviation was most frequently accompanied by crepitus or clicking and Condylar dislocation. • Neuromuscular involvement in TMJ problems was also observed in the lip and tongue areas. www.indiandentalacademy.com
  25. 25. Auscultation • stethoscope is used to check for signs of clicking and crepitus. • A stereostethoseope helps to determine the magnitude and timing of abnormal sounds for each joint simultaneously. • If crepitus is noted, the patient is instructed to bite forward into incision and then repeat the opening and closing movements. These movements are checked for any sounds with the stethoscope. Most often, sounds disappear in the protruded position. www.indiandentalacademy.com
  26. 26. Palpation • • The condyle and fossa are palpated. The posterior surface can be palpated by inserting the little finger in the external auditory meatus and checked for tenderness, synchrony of action, and coordination of relative position in the fossae. • Palpation of muscles of mastication and muscles of facial expression should be carried out. Lateral pterygoid can be palapated by by placing the forefinger behind the maxiilary tuberosity, right above the occlusal plane, with the palmar surface of the finger directed medially toward the pterygoid hamulus. www.indiandentalacademy.com
  27. 27. Functional analysis • . Dislocation of the condyles and discoordination of movements are early symptoms of functional disturbance. • Gnathologic registration may be useful. • Myographic recordings also assist in this functional analysis. Simple electronic devices help measure the silent period of muscular contraction—a cardinal sign of dysfunction in many cases. www.indiandentalacademy.com
  28. 28. • • • • Functional movements of the mandible and condyles are carefully assessed. Maximum opening is measured between the upper and lower incisors with a Boley gauge. In overbite cases this amount must be added and in open bite the distance must be subtracted. The direction of opening and closing movements should be registered graphically with curves. Premature contacts and deviations in sagittal and transverse directions are assessed. Perioral neuromuscular abnormalities, crepitus, and tenderness of the LPM are important signs of early TMJ dysfunction. As a rule of thumb the diagnosis çf incipient TMD can be made if two of these three signs are present. www.indiandentalacademy.com
  29. 29. Prevention of functinal TMDs • • • Early care of deciduous teeth (especially the molars) for caries and interference. Elimination of tooth guidance crossbites and unwanted translatory condylar movement in the deciduous dentition Elimination of neuromuscular dysfunctions (especially those involving the lips) and habits that force the mouth open www.indiandentalacademy.com
  30. 30. Indications of early orhtodontic treatment • 1. Class II malocclusions with excessive overjet, horizontal growth pattern, and lower lip cushioning to the lingual of the upper incisors (lip trap) 2. Deep overbite problems 3. Anterior open bite with associated abnormal llp, tongue, and finger habits 4. Crossbite conditions • In patients exhibiting clicking and functional disturbances, muscle exercises and interceptive appliance guidance (e.g., bite planes, the bionator) are recommended. www.indiandentalacademy.com
  31. 31. Deglutition • In neonates the tongue is relatively large and located in the forward suckling position for nursing. The tip inserts through the anterior gum pads and assists in the anterior lip seal. This tongue position and coincident swallowing are termed infantile or visceral. With eruption of the incisors at about 6 months, the tongue position starts to retract. Over a period of 12 to 18 months, as proprioception causes tongue postural and functional changes, a transitional period ensues. Between 2 and 4 years the functionally balanced, or mature, somatic swallow is seen in normal developmental patterns. • www.indiandentalacademy.com
  32. 32. Symptoms of a retained visceral swallowing • Forward tongue posture • Tongue thrusting during swallowing, • Contraction of the perioral muscles (hyperactive mentalis and orbicularis oris contraction), • Excessive buccinator hyperactivity, and • Swallowing without the momentary tooth contact normally required. • Normal deglutition. • No tongue thrust or constant forward posture occurs. • The tip of the tongue is supported on the lingual of the dentoalveolar area; • The contraction of perioral muscles is slight during deglutition, and the teeth are in momentary contact during the swallowing cycle. www.indiandentalacademy.com
  33. 33. Complex tongue thrusting problem • • Open-bite conditions often exist in both anterior and posterior regions. Elimination of the problem is usually more difficult in a complex tongue thrust, and a long period of retention is necessary to prevent the return of the visceral swallowing pattern Simple tongue posturing: More amenable to interception • localized anterior tongue posturing forward during rest and active function with localized anterior open bite. • Attendant muscle abnormalities are more adaptive than primary • Prognosis for functional therapy is usually good, and autonomous improvement can often be seen. www.indiandentalacademy.com
  34. 34. Treatment options • Myofunctional therapy • Lip exercise • Because of the diversity of tongue function during swallowing, tongue exercises are not recommended before or during treatment. During active treatment, tongue posture and function are controlled by the appliance • If spaces are present, the tongue tends to find them and press into them; hence anterior space closure is advisable. www.indiandentalacademy.com
  35. 35. Examinatin of Tongue • Tongue function, posture, size, and shape are significant. • Factors altering tongue posture: • Class III - Low lying anteriorly postured tongue • Nonphysiologic design of nipple of baby bottles • Nasal and pharyngeal blockade like excessive epipharyngeal lymphoid tissue www.indiandentalacademy.com
  36. 36. Tongue function • • Primary – retained infantile swallow Functional appliance therapy indicated Secondary - basal skeletal dysplasia Functional appliance therapy not indicated www.indiandentalacademy.com
  37. 37. Tongue posture • the basal tongue posture at rest position is assessedat three regions—root, dorsum, and tip. • The root is usually flat in cases of mouth breathing and deep overbite caused by a small tongue; in all other cases, slight contact of the tongue usually occurs with the soft palate. • In Class II. division 1 malocclusions and deep overbite the dorsum of the tongue is arched and high; in all other malocclusions a tendency exists for the tongue to flatten in accordance with the length of the interocclusal space. • The tip of the tongue is usually retracted in Class II. division 1 malocclusions, but in other malocclusion categories a sbght anterior gllding of the tongue tip occurs as the mandible moves into postural rest position. www.indiandentalacademy.com
  38. 38. Tongue size • Macroglossia – fills the oral cavity - narrow epiglottis - peripheral indentations on the tongue - procumbent incisors - protruded tongue - open bite  Etiology  Hypothyroidism  Hyperpituitarism  Down syndrome www.indiandentalacademy.com
  39. 39. Microglossia : 1. 2. 3. The protruded tongue tip reaches the lower incisors at best Floor of the mouth is elevated and visible on each side of the diminutive tongue. The dental arch reflects the small tongue size and is collapsed and reduced, with extreme crowding in the premolar area. 4. A severe Class II relationship is usually evident. 5. Third molars are usually impacted at the angle of the jaw. 6. severe functional disturbances also present due to the lack of centrifugal force of the tongue. 7. The localized effects are extreme. In some cases, teeth from the posterior segments are tipped so markedly to the lingual that they touch each other in the midline. the effects limited mostly to the dentoalveolar area. www.indiandentalacademy.com
  40. 40. • In the case of hypoglossia the functional abnormality primarily affects the dentoalveolar region, not the basal skeletal structure. Oral and vestibular screens incorporated into functional appliances have similar capabilities. Fixed appliances also have primarily localized effects, which is the reason locating the malocclusion and correcting the sagittal dysplasia are so important before applying even simple inhibitory therapy. www.indiandentalacademy.com
  41. 41. Tongue dysfunction • The most common tongue dysfunctions involve selective outer pressure (pressing) and tongue biting. Tongue thrusting can be anterior, posterior, or combined. The consequences of the localization of aberrant pressures depend on the area of applied pressure: 1. Anterior open bite results from anterior tongue thrust and posture. 2. Lateral open bite and deep overbite result from lateral tongue thrust or postural spread that causes infraocclusion of the posterior teeth. 3. Edge-to-edge incisal and cuspal relationships. • www.indiandentalacademy.com
  42. 42. • Open bite: Dentoalveolar anterior and posterior open-bite problems are usually attributable to abnormal tongue posture and function and usually respond successfully to functional appliance intervention in the mixed dentition. • Deep bite: This also is true for eases of deep overbite in which lateral tongue spread during function and posture leads to infraclusion of the posterior teeth. The space is maintained by invagination of the peripheral portions of the tongue into the interocclusal space while the mandible is in the postural rest position. In such cases, a large freeway space is evident, and the deep overbite is functional. www.indiandentalacademy.com
  43. 43. Functional pseudo- overbite • • • • Caused by supraclusion of the incisors small freeway space is apparent. Functional appliance is indicated in the absence of developmental disturbances Fixed appliances and orthopedic guidance serve better. Surgery is the ultimate treatment. Skeletal open bite:     Genetically determined vertical growth pattern marked antegonial notching. Prognosis for orthodontic therapy is unfavourable. Bimaxillary protrusion: occurs when tongue thrusting is seen in horizontal growers. Simulataneous spacing in both upper and lower incisors is evident.  In a vertical growth pattern th tongue thrust can open the bite, and the lower incisors may be tipped lingually. www.indiandentalacademy.com
  44. 44. Examination of the lips 1. If only a slight contact or a very small gap is evident between the upper and lower lips, the lips are competent. 2. If a wide gap is present with the lips – incompetent lips 3. If the lips seem normally developed but the upper incisors are labially tipped, making closure difficult – potential lip incompetency. The lower lip trap then enhances the already excessive overjet, makes the upper incisors mobile & retrocline and crowd the lower incisors. Early treatment of these problems is an important preventive measure. 4. If the lower lip is hypertrophic, everted, and redundant (i.e., with an excess of tissue), little can be done to improve the situation by orthodontic therapy. www.indiandentalacademy.com
  45. 45. Dysfunction of the lips • The most common is sucking or biting of the lower lip, known as mentalis habit. In this type of dysfunction, contact usually occurs between the tongue and lower lip and can be observed during swallowing. Consequences of the combined muscle abnormality include the opening of the bite anteriorly and the lingual tipping of the lower incisors with crowding and labial malpositioning of the upper incisors. Retraction or dehiscence of the labial gingival tissue overlying the lower incisors can occur. • Upper-lip biting is a habit frequently seen in schoolchildren. It is a stress-strain relief syndrome. Tongue function can be normal, with the hyperkinetic behavioral activity and abnormal lip habit as the main pathologic factors. Class II malocclusion can provide the overjet that requires lip compensation, which in turn exacerbates the original overjet. www.indiandentalacademy.com
  46. 46. • Primary lip dysfunction - overjet with labial tipping of the upper and lingual tipping of the lower incisors is evident, and only a slight skeletal sagittal discrepancy occurs. The lip habit enhances the original slight-to-moderate overjet. • Secondary lip dysfunction - the original overjet is caused by a significant sagittal discrepancy, usually with mandibular underdevelopment. The inclination of the incisors can be normal. The lower lip cushions the gap between the upper and lower incisors, primarily as an adaptation to the morphologic malrelations. Lip activity may not be as intensive but may rather be more adaptive Functional therapy is successful only in cases of primary dysfunction. In the case of secondary dysfunction, functional therapy is inferior to other orthopedic, orthodontic, or surgical methods. www.indiandentalacademy.com
  47. 47. Respiration Mouth breathing: • In 1968, Ricketts described the “respiratory obstruction syndrome,” visceral- type swallowing, predisposition to open bite, unilateral or bilateral crossbite and slight upward deflection of the head. • disturbed nasal respiration predisposes to ClI div 1 malocclusion; narrowness of the upper arch; crowding of the upper and lower arches; and vertical growth patterns. • If the tonsils and adenoids are enlarged, with a compensatory anterior tongue posture, the patient cannot tolerate a bulky acrylic appliance in the oral cavity. • Appliances indicated in mouth breathers - Clark twin block, Hamilton expansion activator • Lip seal is usually inadequate, tongue is a low posture and disturbed function. If this condition persists after treatment, relapse will occur. Orthodontic therapy should aim at establishing normal nasal respiration. Unfortunately in some patients with allergies or deviated nasal septums, this is not possible during the growth period. www.indiandentalacademy.com
  48. 48. • Water hold test can be performed. • The presence and size of the adenoids and tonsils also can be estimated on lateral head films. An arbitrary scale of small, medium, or large can be used in both the clinical examination and the lateral cephalogram. • Spontaneous regression of epipharyngeal lymphoid tissue occurs with development. At 10 years of age, 180% of the lymphoid tissue is present that will still be present at 18 years of age. Obstructive adenoids usually regress without surgical intervention. • Nasal respiratory resistance also can be measured using an indirect polysomnographic approach. • In habitual mouth breathing, respiratory resistance is low, whereas in structurally conditioned mouth breathing, it is high. The diagnosis of mouth breathing is probably best made by the otolaryngologist. www.indiandentalacademy.com
  49. 49. Functional therapy in respiratory problems 1. In habitual mouth breathing with small respiratory resistance, functional therapy is indicated. Exercises can be prescribed. Holding a sheet of cardboard between the lips is one satisfactory means of enhancing lip seal. 2. If structural problems occur with excessive adenoid tissue and allergies, ENT consultation and possible treatment should be sought. If it is successful, orthodontic treatment can then begin. 3. If the structural conditions are unalterable, functional appliance therapy cannot be instituted. In such cases, only active fixed-appliance mechanotherapy is likely to produce the changes desired. Even then, the stability of the results is questionable unless autonomous improvement occurs. www.indiandentalacademy.com
  50. 50. Significance of Functional Analysis in Treatment Planning with Removable Appliances Class II malocclusion: • • • • Anterior postural rest position of the mandible Large freeway space, Mandibular overclosure, and deep bite Early TMD symptoms with deep overbite, horizontal growth pattern, and abnormal perioral muscle function. • Respiratory disturbances potentially interfering with normal growth and developmental pattern should be eliminated (if possible) before orthodontic treatment. www.indiandentalacademy.com
  51. 51. Class III malocclusion: • Prognosis is favorable in mild to moderate skeletal class III (true forced bite) intervened at an early stage. • Unfavorable when pseudo forced bite characterized by partial dentoalveolar compensation with anterior sliding on closure. Open bite malocclusion: • . In primary dysfunctions with abnormal muscle action as a major etiologic factor, the growth pattern is usually average or horizontal. • If the growth pattern is mostly vertical, the dysfunction may be more secondary or adaptive. • Functional appliances are likely to be successful in cases with primary dysfunction and at least an average growth pattern. www.indiandentalacademy.com
  52. 52. Cephalometric for functional appliance therapy www.indiandentalacademy.com
  53. 53. Analysis for facial skeleton 1.Saddle angle (N-S-Ar) • Normal 123±5º • Less than 118º -Antr post gl.fossa- favorable • Greater than 128º-postr post gl.fossa -favorable Look for – 1.Articular angle - less than 143±6º- favorable 2.Ramal length- Long - favorable Uncompensated: Greater saddle angle + greater articular angle + Lesser ramal angle-unfavorable www.indiandentalacademy.com
  54. 54. 2.Articular angleS-Ar-Go angle Upper and lower parts of the posterior contours of facial skeleton • Large art in retrognathic mandible • Small art angle in prognathic mandible • Can be altered by orthopedic and orthodontics • Reduction in the Ar angle 1.Anterior repositioning of Md 2.Closing the bite 3.Mesial migtratin of molars Between 9-15 years: Decreases by 2.5* for vertical growers and 2.9* in horizontal growth www.indiandentalacademy.com
  55. 55. 3.Gonial angle • Shows – 1. Form of the md. 2. Direction of mandibular growth - where functional appliance indicated. • Small lower gonial angle -horizontal grower – favorable • Large lower gonial angle-vertical grower - unfavorable if growth is considered during appliance fabrication, then it can be used as initial therapy but finally – surgery 9yr – gonial angle 125.5º Lr gonial angle - 69.5º- hor 133.4º 78.3º-ver • Decreases 2.89º-horizontal growth 2.42º-vertical growth www.indiandentalacademy.com
  56. 56. 4. Jarabak ratio: Postr face ht×100 = 62 to 66% Antr facial ht 9yrs H • Post facial ht. 69.5 • Antr facial ht. 103 • • V 64.1 106.6 9-15yrs H 11.05 12.18 Hor 67.5%-69.9% Ver 60.1%-62.7% www.indiandentalacademy.com V 10.8 12.71
  57. 57. 5. Antr cranial base length (Se-N) • Horizontal growth 68.8mm at 9 yrs and increases by 4.46mm between 9- 15 yrs • Vertical growth 63.8mm and increases 3.52mm between 9- 15 yrs. Therefore greater antr cranial base length in horizontal & lesser in vertical growth 6.Postr cranial base length (S-Ar) • Depends on posterior face ht and position of gl.fossa • Short postr cranial base is seen in 1. Vertical growers 2. Skeletal open bite • • Hor – 32.2mm Ver -30mm 9.16mm (in 6yrs) 9-15 yrs 4.47mm www.indiandentalacademy.com
  58. 58. Analysis of jaw bases 1.SNA- Sagittal relation of the antr limit of the maxillary apical base Average 82.2 ± 2º - if larger than 84º functional appliance is contradicted SNA doesnt change significantly with functional appliance 9yrs 79.5 79.73 79.0 15yrs 81.28 81.57 80.57 • • • Avg Hor Ver • • Functional appliance can decrease SNA to a moderate extent. A significant decrease is possible by H activator(7-8mm sagittal & 23mm vertical) or a twin block www.indiandentalacademy.com
  59. 59. 2.SNB- Smaller indicative of retrognathic mandible - Functional appliance is indicated • Hor- 77.2º-80.5º (3.2º) • Ver- 74.3º-75.9º (1.6º) Therefore growth directions and greater increments make the success of the functional therapy. 3.Basal Plane Angle (pal-mp) • Hor – small 23.4º-20.5º (-3º) • Ver – larger 32.9º – 30.9º (-2º) www.indiandentalacademy.com
  60. 60. 4.Inclination angle 85º(PP-Pn)Anteinclination is seen in horizontal growers and mouthbreathers Retroclined palatal plane is present in compensated ver growers Doesnt correlate with growth pattern or facial type But maxillary base inclination changes with fnl appl therapy • Therefore mid treatment evaluation is indicated periodically www.indiandentalacademy.com
  61. 61. 5. Rotation of the jaw bases: A) Intermatrix rotation B) Matrix rotation = total rotation is what we see cephalometrically. • • • Remodelling of mandible at the gonial and symphyseal area Horizontal – apposition at gonial, resorption at symphysis. Vertical – apposition at the gonial, and resorption at genium. • • Matrix rotation – neurovascular envelope Functional appliance and growth can influence the mandibular rotation Maxillary base is not altered by growth, but environmental factors like neuromuscular dysfunction, occlusal forces, gravity and nasorespiratory malfunction. • www.indiandentalacademy.com
  62. 62. 6. Mutual rotation of jaw bases: Horizontal rotation – deep bite – convergent rotation Vertical rotation – open bite – divergent rotation Cranial rotation of both bases – offset deep bite Caudal rotation both bases – offset open bite Therapeutic control of vertical dimension is not possible and therefore compensatory treatment is indicated. www.indiandentalacademy.com
  63. 63. 7. Linear measurement of the jaw bases: • • The length of mandibular and maxillary bases and ascending ramus is measured relative to Se – N. Ideal dimensions can be calculated using the ratios: N-Se:Md base 20:21 Asecending ramus:Md base 5:7 Max base: Md base 2:3 Mandibular base: The mandibular base should be 3 mm longer than Se-N until 12th year and 3.5 mm longer after 12th year. A length 5mm less than this average is considered normal until 7 years and length 5mm or more is considered normal until 15 years. 9 yrs 15 yrs Horizontal pattern 67.59 mm 77.35 mm Vertical pattern 65.23 mm 73.5mm www.indiandentalacademy.com
  64. 64. Extent of maxillary base: • It is the distance between PNS and Pt A projected perpendicular to palatal plane. • Growth potential of mandible is greater than that of maxilla hence SNB angle increases and ANB decreases. 9 years 15 years Horizontal patterns 44.56 mm 48.6 mm Vertical patterns 44.0 mm 47.16 mm Length of ascending ramus: • Measured from gonion to condylion. Condylion is constructed by the intersection of FH plane on the tangent to the ramus. • Ideal FH plane is also constructed “distance between soft tissue nasion and palatal plane is bisected along the Pn line. From this point a straight H line is drawn paralel to Se-N plane.” • Ramal length determines the posterior facial height. • It is longer in horizontal growers with 48.9mm at 9 years increasing to 68.6 7mm at 15 years. • It is shorter in vertical growers 44.47 mm at 9years 51.7 mm at 15 years. www.indiandentalacademy.com
  65. 65. Evaluation of the length of the jaw bases 1. • Mandibular base: Md base = N-Se + 3mm indicates an age related normal mandibular length and an average growth increment. • If the base is shorter the growth increment is larger, if the base is longer the growth increment is shorter. • Retrognathic mandible may have short or longer base. Short base – retrognathism is due to growth deficiency Long base 1) functional retruded position because of overclosure or occlusal guidance 2) the mandible is morphologically built into the facial skeleton in a posterior position. www.indiandentalacademy.com
  66. 66. 2. Maxillary base: It is related to N-Se and to the Md base. Deviation from the Md base indicates that the Mx base is too short or too long. 3. Ascending ramus: If the ramus is too short, a large amount of growth can be expected because the growth pattern is not vertical. 4. Morphology of the mandible: • Orthognathic type – width of ramus is equal to ht of body of mandible including ht of alveolar process and incisor. The condyle and coronoid are almost on same plane. • Retrognathic – the ramus is narrow and short, the symphysis narrow and long. The coronoid process is shorter than condyle and the gonial angle is acute or small. • Prognathic – ramus is wide and long, symphysis is wider in saggital plane, the gonial angle is acute or small. www.indiandentalacademy.com
  67. 67. Analysis of dentoalveolar relationship Axial inclination of the incisors: 1. Upper incisors: Upper incisor to SN angle: a. 94 -100* until 7th year b. 102* in the permanent dentition c. larger angle indicates incisor procumbancy 2. Lower incisors: Incisor to mandibular plane angle: 90* - average smaller angle – lingual tipping of incisors – advantageous for functional appliance treatment. Activators are more effective in the saggital plane and tend to tip the lower incisors labially. if lower incisors are already labially tipped anterior repositioning of mandible and uprighting of incisors is necessary. www.indiandentalacademy.com
  68. 68. 3. Positioning of the incisors: Maxillary incisor to N-Pog line: 2 to 4mm Mandibular incisor to N-Pog line: -2 to +2 mm Proclined incisors are tipped, if the axial inclination is correct, then bodily movement is required. Mandibular incisors behind this line can be moved labially because space is available and anterior to this line should be moved lingually. www.indiandentalacademy.com
  69. 69. Cephalometric evaluation of treatment progress in mixed dentition www.indiandentalacademy.com
  70. 70. Cephalometric evaluation of A-P discrepancies www.indiandentalacademy.com
  71. 71. • Steiner’s anaylsis: • An ANB angle of 2 ± 2° was considered Class I. • Angles greater than 4° were considered Class II. • Angles less than 0° were considered Class III. www.indiandentalacademy.com
  72. 72. • Wits appraisal in Class I patients with 0 ± 2 mm. • greater than 2 mm indicated a Class II skeletal relation, and • measurements less than – 2 mm indicated a Class III skeletal relation. • The Wits analysis is a function of the inclination of the occlusal plane • So standardization was attempted on the basis of an inclination of the occlusal plane of 8° to the palatal plane (NL). (AJO-85, Williams) www.indiandentalacademy.com
  73. 73. McNamara analysis: • The relationship of either A or Pog to nasion perpendicular of 0 ± 2 mm was considered Class I. • For differences greater than 4 mm between points A and Pog, • If A is anterior to Pog, it is considered Class II. • If Pog is anterior to A, it is considered Class III. www.indiandentalacademy.com
  74. 74. Cephalometric assessment of sagittal relationship using palatal plane - 1994 Apr AJO - Ram Nanda and Merrill • the first part evaluated changes in the inclination of palatal plane and in the linear distances from the age of 6 to 24 years and indicated the inclination of the palatal plane was stable throughout the growth period studied. • The second part established acceptable adult norms by evaluating in non-orthodontically treated with good facial balance. • The third part evaluated the proposed measures in pretreatment radiographs in malocclusions to compare the results of various diagnostic criteria for assessment of sagittal jaw relationships. • The distance between projections from points A and B on the palatal plane (App-Bpp) was found to be the best indicator of sagittal jaw relationship when compared with the angle ANB, the Wits appraisal and N perpendicular, www.indiandentalacademy.com
  75. 75. Changes in palatal plane inclination • The growth changes in the inclination of the palatal plane were measured relative to the pterygomaxillary vertical plane • on an average Pp decreased by 0.16° in the female subjects and increased 2.22° in male subjects from age 6 to 24 years. • The correction factor iwas found to be less than 0.01 mm, which was considered insignificant. • This confirmed the observations that the palatal plane remains relatively stable throughout growth. • This stability over time validates use of the palatal plane as a reference plane for measurement. www.indiandentalacademy.com
  76. 76. Changes during growth • Mean changes in the measurements App-Bpp, AppPogpp, Mpp-Dpp, and Mpp-Pogpp from age 6 to 24 years showed that those persons who are at the extremes at age 6 years may remain at or near the extremes. In some cases they move closer to from the average than they were at age 6 years. • The measures using point Pogpp were more negative than the measurements based on points B and D, and the range was larger. The range for App-Pogpp was 13.66 mm for the women and 24.66 mm for the men. For Mpp-Pogpp the range was 13.94 mm for the women and 24.87 mm for the men. www.indiandentalacademy.com
  77. 77. The advantages of using palatal plane are (1) growth changes of point N do not influence the result (2) rotation of the jaws does not influence the result (3) inclination of the occlusal plane by dental effects is excluded (4) vertical effects of points A and B are decreased in comparison to other methods of analysis. (5)Palatal plane is to be preferred over the FOP because the occlusal plane changes its inclination during growth and with orthodontic treatment. www.indiandentalacademy.com
  78. 78. (6)Palatal plane is desirable since this skeletal plane is in close proximity to the areas under consideration. (7)The proximity of palatal plane to the dentitions and their apical bases in both the maxilla and the mandible allowed an evaluation of the maxillomandibular complex by relating the mandible to the maxillary plane and not by how the maxilla and the mandible related to nasion, cranial base, functional occlusal plane, or any other distant reference point. (8)Palatal plane was also selected because it is stable throughout life. • The palatal plane appeared to maintain a parallel relation over the growth range Broadbent. • The palatal plane maintained a constant angular relationship with the anterior cranial base –(Brodie, Bjork) and to the pterygomaxillary vertical plane (Riolo) www.indiandentalacademy.com
  79. 79. Appraisal by linear measurements has distinct advantages over angular measurements 1. There are fewer variables to affect the accuracy of the linear measurement, and 2. there is less error of measurement. 3. Angular changes are complex measurements because in any angular measurement the position of three points is involved. 4. The effect of angular changes also becomes larger as you move away from the vertex of the angle being measured. www.indiandentalacademy.com
  80. 80. • App – Bpp (5.2 ± 2.9 mm in women 4.8 ± 3.6 mm in men) • App – Pogpp (2.5 ± 4.3 mm for women 2.4 ± 5.4 mm for the men.) • Mpp – Dpp • Mpp – Pogpp • The size of the bony chin Pog is highly variable between persons hence greater range of values observed for App-Pogpp and Mpp-Pogpp. • Chin size and shape may be related to secondary sexual characteristics. • Pogonion is important in determining the facial profile, especially in the adult. www.indiandentalacademy.com
  81. 81. • App-Bpp, App-Pogpp, Mpp-Dpp, and MppPogpp decrease during growth. • Class I malocclusions App-Bpp (6 to 24 years) 2.5 mm in female 0.8 mm decrease in male. The values for the persons with Class I malocclusions from age 6 years onward were within the normal adult range derived in this study. This indicates that this method of analysis may be applied as early as 6 years of age. www.indiandentalacademy.com
  82. 82. • Unlike Class II, Division 1 malocclusions, the persons with Class II, Division 2 malocclusions had a greater decrease in the App-Bpp • Became slightly more protrusive than those of the Class I sample with 0.5 mm more protrusion for the women and 1.5 mm more for the men. • Md values remained within normal range from the age of 12 • Class II, Division 2 malocclusion is considered to be a dental malocclusion with a strong genetic component combined with a normal skeletal pattern www.indiandentalacademy.com
  83. 83. Class II subdivision • The mean values for Class II subdivision subjects were within the range of normal. This was not unexpected as this malocclusion is frequently considered to be a variation of Class I. Usually it is a result of asymmetrical mesial drift of the maxillary permanent first molar because of premature loss of a primary second molar, or unfavorable tooth eruption in the maxillary arch. www.indiandentalacademy.com
  84. 84. Class III malocclusion • In a Class III malocclusion from age 6 to 24 years because of a larger anterior growth of the mandible, the maxillomandibular relation measured considerably more in the negative direction. • Beyond the age of 12 years,, the measurements became progressively smaller due to maturation. Men show changes beyond age 18 years. • Low FMA might be associated with a lower AppBpp measurement. This correlation is very weak www.indiandentalacademy.com and statistically significant only in men.
  85. 85. • In determining the norms for the measurements on palatal plane, a variance of one-half standard deviation from the mean was selected. This range was defined narrowly because in malocclusions one is dealing with normal and its variations so that measures of normal need to have a narrow range to be able to differentiate between the variations seen in malocclusions. • There is no significant difference in the sagittal jaw relation as indicated by the App-Bpp measurement between the persons with Class I, Class II, Division 2, and Class II subdivision malocclusions. The persons with Class III and Class II, Division 1 malocclusions were significantly different from the normal. www.indiandentalacademy.com
  86. 86. Pitchfork analysis - Lysle Johnston !996 JO • Aim: Correction of molar relationship and overjet — assessment of physical displacements produced by growth and tooth movement: • displacement of maxilla relative to cranial base, • movement of maxillary dentition relative to maxillary basal bone, • translation of mandible relative to cranial base, and movement of mandibular dentition relative to mandibular basal bone. www.indiandentalacademy.com
  87. 87. • The so-called ‘pitchfork’ diagram provides a convenient and logical means of organizing and summarizing the various components of change that come together at the occlusal plane. www.indiandentalacademy.com
  88. 88. • Bodily translation of basal bone can move teeth; surface changes cannot. The pitchfork analysis thus requires that we measure skeletal change as actual physical displacement, rather than apparent change in the position of a landmark due to surface remodelling. • The change in the molar and incisor relationship can be expressed as an exact algebraic sum if the component displacements are measured in a comparable manner and each is given a sign appropriate to its impact: – positive if it would tend to correct a Class II molar relationship or reduce overjet (with forward growth of the mandible or mesial movement of the lower molars and incisors); – negative, if it increases the overjet or moves the molar relationship toward Class II (e.g. as with forward growth of the maxilla or mesial movement of the upper dentition). www.indiandentalacademy.com
  89. 89. Advantages: 1. Allows comparisons of change between treatments and between treatment phases, not only with respect to magnitude, but also source (i.e. skeletal or dental). 2. It will always be internally consistent: the components of growth and tooth movement, no matter how they are measured, will add up to the total molar and overjet correction. 3. Regional superimposition on stable anatomical details aids to standardize the position of landmarks in the bones whose displacement is to be measured. 4. The impact of remodelling on surface landmarks does not affect the measurements made. Disadvantages: 1. Although growth and treatment interact in all 3 planes of space, only a-p changes are considered (because of the author’s interest) 1. The analysis is based on tracings & superimpositions of shared anatomical details that may differ from patient to patient so its difficult to get a computer program for digitization to generate tracings and to execute measurements. www.indiandentalacademy.com
  90. 90. Pitchfork analysis: • Apical base change (ABCH)= the sum of maxillary + mandibular translatory growth relative to cranial base • Change in molar relationship =ABCH + upper + lower molar movement • Change in overjet = ABCH + upper + lower incisor movement. The analysis is based on 3 superimpositions: • Cranial base • Maxilla • Mandible www.indiandentalacademy.com
  91. 91. • Superimposition of the cranial base – along the antr cranial base. • S-Na change with local remodelling during growth. • So the superimposition is done along the anterior half of sella turcica to foramen caecum and the internal outline of the frontal bone. (de Coster 1951) • And also over the greater wing of sphenoid, the cribriform plate, the orbital roofs. (Bjork) www.indiandentalacademy.com
  92. 92. Superimposition of the maxilla: • Maxillary superimposition along ANS-PNS in with registration on ANS or the lingual palatal curvature. • The superior and inferior surfaces of the posterior hard palate assist in orientation, and to minimize the probability of gross errors in antero-posterior registration, care should be taken to ensure that the PTM fissure of the older tracing lies at or behind that of the younger. www.indiandentalacademy.com
  93. 93. • Mandible Mandibular regional superimposition. Registration is achieved by aligning the bony architecture of the facial half of the symphysis orientation, by aligning the mandibular canals or molar tooth germs. The superimposition is used to carry both the fiducial line and D point (the centre of the bony symphysis, by inspection) through from one tracing to the other. www.indiandentalacademy.com
  94. 94. • ‘Fiducial lines’ are arbitrary straight lines several inches long marked on either end with registration crosses. • Such lines are drawn adjacent to cranial base, maxilla, and mandible of one tracing (say, from the middle of the series). • It is important to note that once a tracing has been used in a superimposition, its fiducial lines are inviolate. • Once the fiducial lines have been transferred throughout the series, they serve not only to record the super- impositions to facilitate the process of measurement, but also to provide a greatly simplified picture of change seen from the vantage point of any of the three facial areas. • If, for example, the cranial-base fiducial lines are superimposed, the separation of the mandibular and maxillary fiducial lines represents the translatory growth—both in amount and angulation—of the jaws relative to cranial base. www.indiandentalacademy.com
  95. 95. Measurement of change • Based on the ideas of Wendell Wylie, Jacobsons ‘Wits’ analysis (Jacobson, 1975), and the analytic methods of D. Harvey Jenkins (1955) • The superimpositions are recorded by arbitrary fiducial lines. Maxillary advancement relative to cranial base (MAX) is measured at W; Mandibular displacement relative to maxilla (ARCH) is measured at D. Both measurements are executed parallel to MFOP. www.indiandentalacademy.com
  96. 96. • The pitchfork analysis uses a ‘functional’ occlusal plane (FOP) (Jenkins 1955) and defined as ‘...the average occlusal plane of the buccal teeth, including canine and first permanent molar’ • FOP is a best-fit line passing through the occlusal overlap in the region of the first molars, premolars, and canines (especially when premolars have been extracted). • Thus, it is insensitive to incisor movement, it is representative of the bulk of the buccal occlusion, and it is relatively stable over time, although its angulation with respect to cranial base tends to decrease slightly and progressively as the mandible outgrows the maxilla. • the line (sic) is placed by inspection, either with respect to the radioopacities created by cuspal overlap or to the radiolucencies scattered among cusps along the line of the occlusion • The resulting best-fit orientation then is copied through to the overlying tracing. In general, the pre-treatment FOP tends to cant downward a few degrees relative to DOP but at the end of treatment, however, the two lines commonly coincide. www.indiandentalacademy.com
  97. 97. • Jaw growth displacement relative to cranial base To measure displacement of the maxilla relative to cranial base (MAX), the maxillary fiducial lines are superimposed and the separation of the W points is measured parallel to MFOP. maxillary rotation impacts measurements of both maxillary and mandibular growth/advancement: ‘clockwise’ rotation increases both; ‘anticlockwise’ rotation decreases both. On average, however, maxillary basal rotation is minimal and thus its effect on the analysis is: probably negligible. • Next, the separation of D-points (standardized in the two tracings by mandibular regional superimposition) is measured parallel to MFOP. This measurement represents apical base change (ABCH), the growth/displacement of the mandible relative to maxillary basal bone. • Given the usual pattern of facial growth in which the mandible ‘outgrows’ the maxilla, ABCH commonly is positive. It should be emphasized that this displacement of D-point can be due to growth, a functional shift, or, more probably, mixture of both. www.indiandentalacademy.com
  98. 98. Tooth movement relative to basal bone To trace the outline of a tooth, one has the option of making a custom template from the best film in the series or, indeed, from parts of several films. One can add a long axis, contact points, etc. and then use best-fit superimposition on the film to transfer the template outline to each tracing in the series. Although this method does not guarantee that the teeth will be rendered correctly, it standardizes details that should remain constant (tooth form, size, long-axis orientation, etc.) and thus serves to optimize the measurement of change within a given series. www.indiandentalacademy.com
  99. 99. • Tooth movement is measured parallel to MFOP superimposing within either the maxilla or mandible. • Molar crown movement is measured at the mesial contact point; • Molar root movement from the point at which the long axis is crossed by a line drawn between the apices of the buccal roots. Crown movement is the algebraic sum of root movement and a component due to tipping. Thus, the tipping component can be estimated by subtracting root movement from crown movement. www.indiandentalacademy.com
  100. 100. • Symphysis, mandibular canal, molar tooth-germs are used to establish a mandibular superimposition and a single D-point is transfered throughout the series. • Tooth movement then is measured with reference to an orientation on MFOP and a registration on a perpendicular from MFOP erected through D. • Displacement of the crown (mesial contact point) and roots of the averaged first molars and the incisal edge of the averaged central incisors is measured parallel to MFOP. • Orientation along MFOP requires a rotation of the corpus that facilitates the measurement of molar movement, but which eliminates the buccal-segment eruption that commonly occurs secondary to forward growth rotation of the mandible. Given the present emphasis on anteroposterior change, the resulting ease of analysis more than offsets the loss of vertical information. • www.indiandentalacademy.com
  101. 101. • Molar relationship and overjet change The change in molar relationship is measured by registering on the mesial contact point of one molar (upper or lower) and then measuring the separation of the contact point of the other; the change in overjet, by registering on the averaged incisal edge of the upper or lower incisors and then measuring the displacement of the averaged incisal edge in the other arch. It is helpful to execute the various measurements with the aid of a magnifying glass and electronic vernier calipers for internal consistency. www.indiandentalacademy.com
  102. 102. VTO • Growth and treatment prediction 1. Cranial base prediction • nasion and basion grow 1mm/ year each. • Traced superimposing on cc point 2. Mandibular growth prediction: i) Rotation: facial axis opens by 1* for every - 5mm of convexity reduction - 3mm of molar correction - 4mm of overbite correction - half the quantity for cross bite correction • DC descends 1mm/year • PM descends 2mm/year www.indiandentalacademy.com
  103. 103. 1. Superimpose on condylar axis (DC – Xi) draw the posterior border of ramus and the lower border of mandible 2. Slide along the corpus axis (Xi – PM) draw the new symphysis and mark the Me. Maxillary growth prediction Divide Me – new Me distance into three equal parts with two marks. Superimpose on mark 1 and along the facial plane to trace the palate ( except point A). www.indiandentalacademy.com
  104. 104. Point A prediction: 1. With headgear pt A moves distally by 8mm 2. With activator 2mm 3. With torquing 1-2 mm 4. Class II elastics 3mm 5. Pt A moves mesially 2-3mm with facemask and class III elastics. For every mm distal movement Pt A descends down by 0.5mm. Occlusal plane prediction: 1. Superimpose old Me on mark 2 and tilt the tracing to parallel the mandibular plane. 2. OP tips down (clockwise) for class III correction 3. Anticlockwise for class II correction www.indiandentalacademy.com
  105. 105. • 1. 2. 3. 4. 5. 6. 7. Dentition prediction: Superimpose on corpus axis at Ptm and mark the lower incisal edge 2mm ahead of A-Pog line and 1 mm above the OP. Draw the ideal LI at 22* to A-Pog. If a compromise in protrusion should occur then for every 1mm, 2* proclination is to be reduced. Lower molar normally grows 2mm mesially for every 1mm eruption. Upper molar is drawn in class I relation according to the lower molar position. Draw UI with ideal 131+/- 10* to LI. In case of open bite correction interincisal angle is placed at 141* and 121* for deep bite. www.indiandentalacademy.com
  106. 106. Soft tissue prediction Nose prediction: 1. Superimpose nasion along the N-Pog line to trace the bridge of the nose. 2. Place ANS along the palatal plane and move back by 1mm per year to trace the nose tip. Soft tissue Point A 1. Superimpose on N-Pog and OP 2. Mark old and new upper incisal tips 3. Divide the distance into three parts 4. Superimpose new incisor at mark 1 to trace the upper lip and soft tissue A point. Soft tissue B point: 1. Bisect the new overjet and overbite and superimpose the UI at that point and trace the lower lip. 2. B’ is inferior to the original B’ because recontouring drops the lip down. 3. Variations: Increased lip drop is found in opening the bite and with correction of lip strain. www.indiandentalacademy.com
  107. 107. Skeletal Maturity Indicators www.indiandentalacademy.com
  108. 108. Standing height 1. Statural height and hand-wrist skeletal maturation in both sexes are significantly related. Maturity scores of girls at age 13 correlate best with velocity of height between the ages of 13 and 14 years. Maturity scores of boys at age 16 correlate best with velocity of height between the ages of 15 and 16 years. 2. the correlation coefficients were relatively small between height velocity and facial dimension velocity to be statistically significant. The correlation coefficients between skeletal maturity scores and changes in facial dimension were even smaller. Therefore the relationship between acceleration and deceleration in growth of specific craniofacial dimensions and statural height or skeletal maturity is not clinically significant for prediction. However, it may be used as a factor for consideration in diagnosis and treatment planning in an individual case. Sagittal jaw relationships are difficult to evaluate because of rotations of the jaws during growth, vertical relationships between the jaws and the reference planes, and a lack of validity of the various methods proposed for their evaluation. - Moore & Moyer, AJO ‘90 www.indiandentalacademy.com
  109. 109. STANDING HEIGHT. • The mean age for the maximum growth velocity from 8 to 17 years was 13.0 years for boys and 10.8 years for girls. • The mean age of least growth velocity immediately prior to the age of maximum growth velocity was 10.1 years for boys and 8.5 years for girls. • The minimum occurred an average of 3.0 years before the maximum for boys and 2.3 years for girls. (1) the growth profile of height was significantly different from that of the parameters describing mandibular length and relationship (2) the changes in standing height are significantly different in the maximum, premaximum, and postmaximum periods of growth in both males and females (3) the changes in mandibular length (Ar-Pog) are significantly different in the three periods (4) the changes in mandibular relationship were not significantly different in the maximum and premaximum periods in either males or females, while the magnitude of change in the postmaximum period tended to be smaller than the other two periods (5) autocorrelation analysis revealed that the growth profile of height was found to have little predictive value in determining the growth profile of any of the mandibular parameters except for Ar-Pog for females. -Bishara www.indiandentalacademy.com AJO 1981
  110. 110. Conclusion • Most observers consider cephalometric and plaster cast records as static reproductions, but both have functional analysis potential if used correctly. • Much can be learned from them about the dynamics of the stomatognathic system. • Thus functional analysis is of equal importance to the usual clinical examination and static, cephalometric, and study model analyses. • It is especially significant in treatment with functional appliances because of the dynamic basis of therapy. www.indiandentalacademy.com
  111. 111. Thank you www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com

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