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orthodontic Diagnosis /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.

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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    orthodontic Diagnosis  /certified fixed orthodontic courses by Indian dental academy orthodontic Diagnosis /certified fixed orthodontic courses by Indian dental academy Presentation Transcript

    • FUNCTIONAL ANALYSIS www.indiandentalacademy.com
    • INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
    • • Modern orthodontics is not only restricted to static evaluation of the teeth and their supporting structures, but also includes all functional units of the masticatory system (according to Eschler,1952), i.e. the somatognathic system. Therefore functional analysis constitutes a considerable part of clinical examination, helps in etiologic evaluation of the malocclusion and determining the type of orthodontic treatment indicated. www.indiandentalacademy.com
    • Three most important aspect of Functional analysis are: • Examination of the postural rest position. • Examination of the temporomandibular joint. • Examination of orofacial dysfunction. www.indiandentalacademy.com
    • Examination of the relationship: Postural Rest PositionHabitual Occlusion • Determination of the postural rest position. • Registration of the postural rest position. • Evaluation of the relationship: postural rest position-habitual occlusion, in three planes of space. www.indiandentalacademy.com
    • • In postural rest position, synergistic and antagonist 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. The rest position should be determined with the patient relaxed and sitting upright. Patient should be looking straight ahead and the frankfurt horizontal plane parallel to the floor. www.indiandentalacademy.com
    • Determination of the postural rest position • In order to determine the PRP, the patient’s orofacial musculature must be relaxed. When the mandible is in PRP, it is usually 2-3 mm below and behind the centric occlusion. The space between the teeth is referred to as the freeway space or interocclusal clearence. www.indiandentalacademy.com
    • Several methods are available to determine the postural rest position: • Phonetic exercises. • Command methods. • Noncommand methods. • Combined methods. www.indiandentalacademy.com
    • Phonetic exercise • Patient is told to pronounce certain consonents or words repetitively e.g. Mississippi. The mandible returns to the postural resting position 1-2 seconds after exercise, then dentist gently parts the lips to observe the interocclusal clearence and tongue posture. In mixed dentition language habits vary and not stabilized so this method is less used as prime determinants. www.indiandentalacademy.com
    • Command method • The patient is asked to perform selected functions; the mandible returns to the PRP after each function. Usually, having the patient lick the lips and then swallow produces the desired relationship as mandible returns to PRP with in 2 secs after exercise. www.indiandentalacademy.com
    • Noncommand method • In noncommand method the patient has no idea of the parameter being examined. Careful observations are made as the patient talks, swallow, and turns the head while being questioned on a number of unrelated subjects. www.indiandentalacademy.com
    • Combined method • This method usually provides the best reproduction of PRP in the mixed dentition. • The patient performs a prescribed function e.g. swallowing and then relaxes. After instructing the patient not to move, the clinician gently palpates the submental muscles to assess whether they are relaxed. An intraoral examination by observing the relationship of the canine is performed. Normally the lower canine is 3mm below the upper canine. An interocclusal space of 4mm may be considered normal. www.indiandentalacademy.com
    • Registration of the postural rest position of the mandible • Various methods are recommended for registration: • Direct intraoral method. • Direct extraoral method. • Indirect extraoral method. www.indiandentalacademy.com
    • Direct intraoral method • This method is performed by using a plaster core registration similar to that sometimes used in prosthodontics. This registration is not feasible in mixed dentition. • Millimetric calipers can be used to record the intraocclusal space in the canine or incisor area. www.indiandentalacademy.com
    • Direct extraoral method • Direct caliper measurements can be made on the patient’s profile by measuring the distance from soft tissue nasion to menton. This measurement is done in both postural rest and habitual occlusion. The difference between the two measurements constitutes the interocclusal clearance. The disadvantage of this procedure are that the soft tissues reduces the reliability. www.indiandentalacademy.com
    • Indirect extraoral method • This method is most reliable: • Roentgenocephalometric registration. • Kinesiographic registration. www.indiandentalacademy.com
    • Roentgenocephalometric registration • Two cephalograms are required, either in lateral or frontal projection depending on how the question is formulated. One radiograph in centric occlusion. One with mandible in its rest position. The rest position and freeway space can be determined by comparing the radiographs. www.indiandentalacademy.com
    • Kinesiographic Registration • The mandibular kinesiographic, according to jankelson(1984), allows the mandibular rest position to be registered three dimensionally. The position of the mandible is recorded electronically by: • A permanent magnet, which is fixed with rapid-setting acrylic to the lower anterior teeth. • A sensor system of six magnetometers mounted on the spectacle frames. www.indiandentalacademy.com
    • • Every movement of the mandible and the attached magnet out of centric occlusion, alters the strength of the magnetic field. These changes are recorded by the sensors, processed in the kinesiograph and displayed on a storage oscilloscope. The mandibular movements and rest position are recorded two-dimensionally on two pre-selectable levels. The electronic circuitry also allows the rest position to be recorded as threedimensional coordinates. www.indiandentalacademy.com
    • Evaluation of the relationship between rest position and habitual occlusion • The movement of the mandible from the rest position to full articulation is analyzed three-dimensionally: In the sagittal, vertical, and frontal planes. • The closing movements of the mandible can divided into two phases: Free phase: Mandibular path from the postural rest to the initial or premature contact position. Articular phase: Mandibular path from the initial contact position to centric or habitual occlusion. In case of functional equilibrium, the articular phase does not occur. www.indiandentalacademy.com
    • • When closing from the rest position, the mandible may undergo both rotational and sliding movement. The objective of this analysis is to determine the amount and direction of movement as well as the proportions of the rotational and sliding components. The following movements of the mandible from the rest position to habitual occlusion must be differentiated for orthodontic diagnosis: • Pure rotational movements • Rotational movement with an anterior sliding component. • Rotational movement with a posterior sliding component. www.indiandentalacademy.com
    • Evaluation in the sagital plane • Class II malocclusions. Treatment prognosis for functional appliance therapy depends on the analysis of relationships and the determination of the path of closure category: • 1. In classII malocclusion without functional disturbances the path of closure from rest to occlusion is straight up and forward, with a hinge movement of the condyle in the fossa. These are true class II malocclusions www.indiandentalacademy.com
    • • 2. In class II malocclusion with functional disturbances a rotatory action of the condyle in the fossa from postural rest to initial contact is evident. From initial contact to full occlusion, condylar action is both rotatory and translatory up and backward. As Boman and Blume (1952) showed in their reserch, this type of activity is most common, particularly in excessive overbite cases. This type of class II cases appears more severe than it actually is sagitally. And have a good prognosis. www.indiandentalacademy.com
    • • 3. In class II malocclusion with functional disturbances in which the path of closure is up and forwards, mandible is anteriorly displaced from the initial contact as the cusp guide the mandible into a forward position, with translatory movement of the condyles down and forward. Rare condition illustrated by Woodside. And this condition is more severe than as it appears with the teeth in occlusion, having a poor prognosis. www.indiandentalacademy.com
    • • CLASS III MALOCCLOSION. Hinge-type of condylar movement is often associated with straight path of closure. The possibility of successful functional appilance therapy of this problem exist only if the magnitude of sagital dysplasia is not too great and the therapy is began in the early mixed dentition. • If the path of closure is up and back the prognosis is poor. • In class III malocclusion with the anterior displacement that creates an up and forward path of closure, the prognosis is much better and the treatment success is possible, even in permanent dentition www.indiandentalacademy.com
    • • Some times a skeletal class III malocclusion is partially compensated by labial tipping of the maxillary incisors and lingual tipping of mandibular incisors. Because of the extreme tipping possible an anterior sliding movement into occlusion can occur. Uprighting the incisors into their proper axial inclinations results in severe class III sagital tooth relationship. Treatment with orthodontic means is difficult because dentoalveolar compensation is not possible; as incisors are already overcompensated before treatment and orthognathic surgery should be considered. This type of malocclusion is reffered to as pseudo-forced bite. www.indiandentalacademy.com
    • Evaluation of path of closure from postural rest to habitual occlusion in vertical plane • This evaluation is of special interest in the assessment of therapeutic potential in deep overbite cases. Two types of deep overbite can be differentiated. • 1. True Deep Overbite. The true deep bite with a large interocclusal clearence is caused by infraocclusion of the posterior segments. It often results from a lateral tongue posture or tongue thrust habit. Treatment in the mixed dentition periods requires the elimination of the enviromental factors inhibiting eruption of posterior teeth. www.indiandentalacademy.com
    • Prognosis is good in a true deepbite problem with a vertical growth pattern. And the prognosis is fair with horizontal growth pattern. www.indiandentalacademy.com
    • • 2. Pseudo-deep overbite with a small interocclusal space already has normal eruption of the poserior segment teeth. Some class II div. 2 malocclusion that produce gummy smile and poor lip line relation fall into this category. The amount of interocclusal clearence is a distinguishing criterion. Clinician must intrude the incisors with slight extrusion of molars; it results in an increases facial height and further TMJ problems. The clinician must derive the maxillary molars distally to control the vertical dimension. Cases with pseudo-deep bite with horizontal growth pattern have poor prognosis. www.indiandentalacademy.com
    • Evaluation of the relationship between rest position and habitual occlusion in the Transverse Plane • The position of the midline of the mandible is observed while the jaw is moved from the postural rest to habitual occlusion. Depending on the functional analysis two types skeletal mandibular deviation can be differentiated • 1. LATEROGNATHY • 2. LATEROCCLUSION www.indiandentalacademy.com
    • • LATEROGNATHY: The center of the mandible is not aligned with the facial midline in rest and in occlusion. These dysplasias constitutes true neuromuscular or anatomical asymmetry. A lateral cross bite with laterognathy is termed true cross-bite. The prognosis is unfavorable for causal therapy. www.indiandentalacademy.com
    • • LATEROCLUSION: The skeletal midline shift of the mandible can be observed only in occlusal position; in postural rest position both midlines are well aligned. The deviation is due to tooth guidance (functional non-true malocclusion). www.indiandentalacademy.com
    • EXAMINATION OF THE TEMPOROMANDIBULAR JOINT • The objective of this aspect of functional examination is to assess whether incipient symptoms of TMJ dysfunction are present. • These symptoms are important for two reasons: 1. Through the early elimination of functional disturbances, some incipient TMJ problems can be prevented or eliminated. This is an indication for early orthodontic treatment. 2. During functional therapy the condyle is displaced or dislocated to achieve a remodeling of the TMJ structures and a change in muscle function. If the temporomandibular structures are abnormal at the start and hypersensitivity is a problem, the possibility of exacerbating the symptoms exist. www.indiandentalacademy.com
    • EXAMINATION OF TMJ: Auscultation Palpation •TMJ Functional Analysis •TMJ •Musculature •TMJ •Mandibular excursion •Occlusion •Rest position •Premature contacts •Dysfunctions Radiographic Examination •TMJ SYMPTOMS •Crepitus •Clicking •Palpatory pain •Dislocation •Hypermobility •Limitation •Deviation •Orofacial dysfunction www.indiandentalacademy.com •Dislocation •Changes in shape and structure.
    • • AUSCULTATION: is carried out with a stethoscope, clicking and crepitus in the joint may be diagnosed during anteroposterior and eccentric movements of the mandible. • JOINT CLICKING IS DIFFERENTIATED AS FOLLOWS: 1.Initial Clicking: is a sign of retruded condyle in relation to the disc. 2.Intermediate Clicking: is a sign of unevenness of the condylar surfaces and of the articular disc, which slide over one another during movements. 3. Terminal Clicking: occurs most commonly and is an effect of condyle being moved too far anteriorly, in relation to the disc, on maximum jaw opening. 4. Reciprocal Clicking: occurs during opening and closing, and expresses an in coordination between displacement of the condyle and disc. Clicking of the joint is rare in children. www.indiandentalacademy.com
    • • PALPATION OF THE TEMPOROMANDIBULAR JOINT: During opening maneuvers will reveal possible pain on pressure of the condylar areas. Besides the right and left condyles can thus be checked for synchrony of action. Palpation – pain on pressure of the condylar areas. Right & left condyles checked for synchrony of action. * Lateral palpation of TMJ – Slight pressure on the condyloid process with the index finger. * Posterior palpation of TMJ – Position the little finger in the external auditory meatus and palpate the posterior surface of the condyle during opening and closing. www.indiandentalacademy.com
    • • Palpation of lateral pterygoid muscle - is palpated close proximity to the neck of the condyle and the joint capsule, cranially behind the maxillary tuberosity. It is carried out with mouth open and mandible displaced laterally. • Palpation of Temoporalis Muscle: Bilaterally & Extraorally www.indiandentalacademy.com
    • Palpation of masseter muscle – Superficial massater muscle is palated beneath the eye, inferior to zygomatic arch. - Deep portion is palpated on the same level, 2 finger width infront of tragus. www.indiandentalacademy.com
    • Recording of the maximum inter incisal distance: Maximum jaw opening – distance between incisal edges of the upper and lower central incisors are measured with Boley gauge. It is usually 40-45mm. In over bite cases this amount is added to the obtained value whereas in open bite it is subtracted. In cases with TMJ dysfunction, hypermobility is often registered in the initial stages and limitation in the later stages. www.indiandentalacademy.com
    • Opening and closing movements of the mandible: • The opening and closing movements of the mandible as well as its protrusive, retrusive and lateral excursion are examined as part of the functional analysis. The size and direction of these actions are recorded during clinical examination. Deviations in speed can only be registered with electronic devices (Kinesiograph). • The first signs of initial temporomandibular joint problems include deviations of the mandibular opening and closing paths in the sagittal and frontal planes. In patients with malocclusion and malaligned teeth, disturbances in mandibular movement are the result of an asynchronic pattern of muscle contractions. The characteristic movement deviations include incongruency of the opening and closing curves and uncoordinated zigzag movements. The “C” and “S” types of deviations are typical signs of functional disturbances. www.indiandentalacademy.com
    • Occlusal analylsis on an articulator is mostly not necessary in adolscents. It is only indicated in patients with manifest symptoms of temporomandibular joint disease. www.indiandentalacademy.com
    • Pattern of mandibular movements during opening and closing maneuvers: Opening and closing paths in sagittal plane.1. opening and closing arcs cross over inconsistency. 2. The opening movements show greater deviations. 3. The closure pattern is straighter and more constant. OPENING AND CLOSING ARCS IN HORIZONTAL PLANE: 1. the opening path is pathologically C-shaped At the end of the closing movement, the mandible shifts slightly toward the left. OPENING AND CLOSING PATHS IN THE FRONTAL PLANE. The extent of jaw opening is normal and mandible towards left due to occlusal interferences. www.indiandentalacademy.com
    • Temporomandibular joint- Radiographic Examination • Only in limited cases radiographic examinations indicated for patients with functional disturbances of the temporomandibular joint. • When analyzing the radiographs following findings are registered: 1. Position of the condyle in relation to the fossa. 2. Width of the joint space 3. Changes in shape and structure of the condyle head or the mandibular fossa. Adolescents with class II, Div. 1 malocclusion and lip dysfunction (lip sucking or sucking) are most frequently affected by TMJ disorders. www.indiandentalacademy.com
    • Diagnostic imaging of the TMJ • PANORAMIC VIEW • TRANSORBITAL VIEW • TRANSPHYRENGEAL VIEW • TRANSCRANIAL VIEW • ARTHROGRAPHY • CONVENTIONAL TOMOGRAPHY • COMPUTED TOMOGRAPHY • MAGNETIC RESONANCE IMAGING • CONE BEAM COMPUTERISED TOMOGRAPHY www.indiandentalacademy.com
    • EXAMINATION OF OROFACIAL DYSFUNCTION CONTANTS • 1. Swallowing • 2. Tongue • 3. Speech • 4. Lips • 5. Respiration www.indiandentalacademy.com
    • SWALLOWING • Normal mature swallowing takes place without contracting the muscles of facial expression. The teeth are momentarily in contact and the tongue remains inside the mouth. • Abnormal swallowing is caused by tongue thrust, either as a simple thrusting action or as tongue-thrust syndrome. The following symptoms distinguish this syndrome: • 1. Protrusion of the tip of the tongue • 2. No contact of the molars • 3. contraction of perioral muscles during deglutitional cycle During their first few years, infants swallow viscerally. i.e. with the tongue between the teeth. As the deciduous dentition is completed, the visceral swallowing is gradually replaced by somatic swallowing. If visceral swallow persists after fourth years of age, it is considered OROFACIAL DYSFUNCTION. www.indiandentalacademy.com
    • Phases of swallowing 1]Preparatory phase • During the first stage food is collected in the foremost part of the mouth, in front of the retracted tongue. The posterior arched part of the dorsum is in contact with the soft palate. The lips are not in contact and the teeth are not occluding. www.indiandentalacademy.com
    • • TRANSPORTING STAGE: 1st part of movement. During the second phase of swallowing, i.e. the transporting stage, the tip of the tongue first moves upward and the anterior section of the dorsum is depressed. 2nd part of movement. The entire anterior section of the tongue then moves upward and the central section of the dorsum is depressed. This peristalsis transports the bolus rearward. www.indiandentalacademy.com
    • • TRANSPORTING STAGE 3rd part of movement At the end of the transporting stage, the soft palate is displaced upward and rearward. The lip musculature contracts simultaneously, the lips are together, the mandible is raised and the teeth come into contact. www.indiandentalacademy.com
    • • THIRD SWALLOWING STAGE The dorsum of the tongue is depressed even further during the third stage so that the bolus can pass through the oropharyngeal isthmus; simultaneously the anterior part of the tongue is pressed against the hard palate, thus forcing more food rearward. Passavant’s pad and soft palate form the palatopharyngeal seal and close the nasopharynx. The teeth are in full occlusion and the lips are in contact. www.indiandentalacademy.com
    • • FOURTH SWALLOWING STAGE During the fourth stage of the swallowing act, the dorsum of the tongue is moved further upward and rearward against the soft palate and squeezes the remaining food bolus out of the oropharyngeal area. www.indiandentalacademy.com
    • FINAL STAGE OF SWALLOWING • Once the swallowing act has been completed the mandible returns to its rest position. www.indiandentalacademy.com
    • VISCERAL OR INFANTILE SWALLOW • Jaws apart with tongue between gum pads. • It is triggered off by sensory interchange between the lips and tongue. • Peristalsis commences in the vestibule • Associated with tongue and mandibular thrust • The transverse section shows that the tongue is positioned low in mouth and that the central furrow is depressed. www.indiandentalacademy.com
    • • SOMATIC SWALLOW: • As swallowing is triggered off by contraction of mandibular elevators, the teeth occlude momentarily during the swallowing act and the tip of the tongue is enclosed in the oral cavity. • Transverse section shows that the dorsum of the tongue is less concave and approaches the palate during swallowing www.indiandentalacademy.com
    • TONGUE THRUST: Tongue thrust has an important effect on the etiopathogenesis of malocclusion. The thrust may take place in the anterior or lateral regions or can be complex Tongue-thrust PRIMARY SECONDARY ANTERIOR LATERAL COMPLEX ENDOGENOUS HABITUAL ADAPTIVE www.indiandentalacademy.com
    • ANTERIOR OPEN BITE Open bite in a deciduous dentition, caused by a tongue dysfunction as a residuum of a sucking habit. HABITUAL POSITION: The tongue is positioned forward during functioning, thus impeding the Vertical development of the dentoalveolar Structures. www.indiandentalacademy.com
    • LATERAL OPEN BITE In this type of open bite the occlusion on both sides is supported only anteriorly and by the first molars. HABITUAL POSITION The tongue thrust between the teeth laterally. The tongue dysfunction occurs in conjunction with a disturbance in the physiologic growth processes around the first and second deciduous molars. www.indiandentalacademy.com
    • COMPLEX OPEN BITE Severe vertical malocclusion. The teeth occlude only on the second molars. Tongue thrusting occurs during function. TONGUE DYSFUNCTION AND MALOCCLUSION In mandibular prognathism, the downward forward displacement of the mandible often causes an anterior tongue-thrust habit. www.indiandentalacademy.com
    • TONGUE FUNCTION: The significance of tongue thrust and its role in the etiology of malocclusion have been evaluated by no. of authors. One school of thought asserts that the tongue thrust is the consequence of an abnormal morphologic relationship, an adaptive phenomenon. Other investigators like Andrew, Hopkins consider tongue thrust a primary etiologic factor for malocclusion. Abnormal tongue posture and function can be primary factors as consequences of retained infantile deglutition patterns or other abnormal oral habits, but they also may be strictly secondary or adaptive to unfavorable morphologic pattern. So tongue thrust may be considered primary or secondary. 1. The primary dysfunctions cause malocclusions and the treatment must concentrate on eliminating the orofacial dysfunction. 2. Secondary dysfunction can be considered an adaptive phenomenon to an existing skeletal or dento-alveolar deviation in the vertical development. These secondary abnomalities usually correct spontaneously while the morphological discrepancies are being treated. www.indiandentalacademy.com
    • CAUSES OF TONGUE DYSFUNCTION CAUSES OF DYSFUNCTION PRIMARY 1. Endogenous 2. Heredity 3. Imitation SECONDARY Adaptive www.indiandentalacademy.com
    • • PRIMARY TONGUE DYSFUNCTION IN CONJUCATION WITH HYPERPLASTIC TONSILS. A retracted tongue would touch infected, swollen tonsils if these were to protrude far out of the surrounding structures. in order to avoid painful sensation and to keep the oral airway open the mandible is dropped and the tongue postured forward. HYPERPLASTIC TONSILS: Moderately swollen palatine tonsils which protrude significantly from the tonsillar sinus. www.indiandentalacademy.com
    • ADAPTIVE TONGUE DYSFUNCTION. After loss of teeth, the tongue is used to fill the gaps, thus Sealing the oral cavity i.e. compensatory dysfunction. ADAPTIVE DYSFUNCTION WITH SKELETAL MALOCCLUSION. Cephalogram of an open bite due to rickets. The tongue Dysfunction is an adaptation to the skeletal and dentoalveolar Morphology. OPEN BITE DUE TO RICKETS. The skeletal and dentoalveolar open bite is aggravated by the adaptive tongue dysfunction. www.indiandentalacademy.com
    • CONFIGURATION OF THE CRANIOFACIAL AND DYSFUNCTIONS • The morphology of the facial skeleton and the effects of tongue thrusting are correlated to a certain degree. • Horizontal growth pattern in conjuncation with tongue thrusting usually results in bimaxillary dental protrusion. www.indiandentalacademy.com
    • • In vertical growth pattern with tongue thrust the lower incisors are often are in lingual inclination. From the differential point of view it is important to clarify both the skeletal relationship and the tongue dysfunction in order to localize the results of the abnormal tongue functioning. www.indiandentalacademy.com
    • METHODS OF EXAMINATION • Various methods can be used to examine tongue dysfunctions. The different types of clinical examinations are : electronic recordings, electromyographic examinations, recording of the pressure exerted by the tongue intraorally, roentgenocephalometric anaylsis, cineradiography, palatographic, neurophysiologic examination. • The position and size of the tongue in relation to the available space is assessed by using roentgenographic cephalometrics. However, in most orthodontic cases, registrating the position of the tongue is more important then determining its size. www.indiandentalacademy.com
    • PALATOGRAPHY It involves recording the contact surfaces of the tongue with the palate and teeth while the patient produces speech sounds or performs certain tongue functions. A thin layer of contrasting precise impression mat. On Patients tongue. Once the consonants are pronounced Patalogram is documented photographically. Accurate prononciation of “S”. During articulation the mandible is lowered and pushed forward. The tongue rests on the teeth and alveolar processes, and a groove is formed in the center throgh which the air stream is directed. INTERDENTAL SIGMATISM (lisping). During this defective pronounciation of the “S” sound, the tongue is usually protruded. www.indiandentalacademy.com
    • PALATAL SIGMATISM. This abnormal pronounciation is caused by an unphysiologic friction noise between tongue and hard palate. LATERAL SIGMATISM ON THE LEFT SIDE. The tongue rest on the anterior teeth. The column of air escapes on the left side. BILATERAL SIGMATISM. Palatogram of this type of defective articulation in a patient with microglossia. SIGMATISM DUE TO LATEROFLEXION TO THE LEFT SIDE. The tip of the tongue is raised too high and rest on upper incisors. The tip of the tongue deviates to the left. www.indiandentalacademy.com
    • TONGUE SIZE: The size and shape of tongue have many variations- bulky and short, narrow and long and wide and long. Numerous clinical methods may be used to assess tongue size. The most common is to check whether the patient can touch the chin with the tongue tip. A positive result is considered an indication of macroglossia.. Other symptoms associated are: 1.The oral cavity is filled by the tongue mass 2.Narrow epipharynx. 3.Indentations on the tongue periphery. 4.Spaces exist between incisors, which are procumbent. 5.Tongue is protruded with open bite present. www.indiandentalacademy.com
    • But in the case with microglossia or hypoglossia, the protruded tongue tip reaches lower incisor at best and the floor of the mouth is elevated and visible on each side. Other features: 1. The dental arch is collapsed and reduced in size 2. Extreme crowding is seen in the premolar region. 3. A severe class II relationship is usually evident. 4. Third molars are usually impacted at the angle of the jaw. 5. In severe cases of microglossia and aglossia posterior segments are tipped so markedly to the lingual that they touch each other in the midline. www.indiandentalacademy.com
    • TONGUE POSTURE: Some investigators hold that the tongue posture is more important than tongue function. The posture of the tongue can be flat or arched, protracted or retracted, narrowed and long, or spread laterally and shortened. Tongue posture is examined clinically with the mandible in the postural rest position. Sagittal cephalometric registration of this relationship also is possible. From the basal tongue posture at rest position an assessment of three regions-root, dorsum, and tip was made and disclosed the following: 1. The root is usually flat in cases of mouth breathing, deep overbite caused by a small tongue; in all other cases, slight contact of the tongue usually occurs with the soft palate. 2. In class II div. I malocclusion with deep overbite the dorsum of the tongue is arched and high; in all other malocclusion the tendency exist for the tongue to flatten. 3. The tip of the tongue is usually retracted in class II div. I, but in all other categories of malocclusions a slight anterior gliding of the tongue tip occurs as mandible moves into postural rest position. www.indiandentalacademy.com
    • METRIC EVALUATON OF TONGUE POSTURE Assessment of tongue size from metric analysis requires measurement of the distance between the superior tongue surface and the roof of the mouth. This is done along the seven constructed lines. These measurements indicate the relative size of the tongue. Only if the entire oral cavity is filled can a diagnosis of macroglossia be made. www.indiandentalacademy.com
    • TRACING OF THE ANALYSIS ON THE LATERAL CEPHLOGRAM. Marking of the contours of the bony palate and dorsum of the tongue. Left. The morphologic relationships in case of retracted, elevated tongue. Right. Relationship in case of a downward forward tongue posture. www.indiandentalacademy.com
    • TEMPLATE FOR METRIC ANALYSIS OF TONGUE POSITION. Transparent plastic template with an inscribed millimeter scale for analyzing the position of the tongue on the lateral cephalogram. The template is oriented on the point O. www.indiandentalacademy.com
    • LIP DYSFUNCTIONS: The etiology of lip dysfunction is similar to that of tongue habits and is assessed in relation to the configuration and functioning of the lips. Configuration of lips: The configuration of lips differs a great deal and can be classified as follows : 1. Competent lips. The lips are in contact when the musculature is relaxed. 2. Incompetent lips. Anatomically short lips with a wide gap between the upper and lower lip in relaxed position. Consciously closed lips. Incompetent lips can only be closed by increasing contraction of the orbicularis oris and mentalis muscle. www.indiandentalacademy.com
    • 3. POTENTIALLY INCOMPETENT LIPS. Upper incisors are labially tipped and their incisal margins interpossed between the lips preventing the normal lip seal. CONCIOUSLY CLOSED LIPS. Lip contact is achieved without increased contraction of the perioral musculature. 4. EVERTED LIPS. Frontal and profile views with lip closed. Due to weak tonicity of the lip musculature, these patient often exhibit bimaxillary dental protrusion. www.indiandentalacademy.com
    • LIP HABITS: Various habits of lips can be divided into: 1. Lip sucking 2. Lip thrust 3. Lip insufficiency Lip dysfunctions can be observed while the patient is speaking and swallowing. The lower lip often shows variations of dysfunction with regard to the tip of the tongue. The lower lip and tip of the tongue are often in contact. In such cases, the lower lip is sucked in and is pressed against the tip of the tongue. It is a symptom of orofacial dysfunction. Visual evidence of mentalis muscle activity is also abnormal. www.indiandentalacademy.com
    • LIP SUCKING. Extra oral findings Lower lip is positioned behind the upper incisors, this malpositioning occurs in conjunction with hyper active mentalis. Lat. Cephalogram indicates that lower lip dysfunction causes further protrusion of the upper incisors. And impedes the forward development of the anterior alveolar process. www.indiandentalacademy.com
    • LIP THRUST. Characteristic profile of the lower third of the face in a case of hyperactivity of the mentalis muscle. Lat. Cephalogram. This type of lip habit is combined with lingual inclination of the incisors. www.indiandentalacademy.com
    • CHEEK DYSFUNCTION: In cases of cheek sucking and cheek biting, the soft tissues are interposed between the teeth, which promotes the formation of the lateral open bite or deep over bite. Increased lateral pressure by the cheek musculature impedes the transverse development of the jaws. www.indiandentalacademy.com
    • HYPERACTIVITY OF MENTALIS MUSCLE: • The deep mentolabial sulcus is characteristic of the hyperactive mentalis muscle. This muscle behavior impedes the forward development of the anterior alveolar process in the mandible. www.indiandentalacademy.com
    • MOUTH BREATHING The mode of respiration is examined to establish whether the nasal breathing is impeded or not. Chronically disturbed nasal respiration represents a dysfunction of the orofacial musculature; it can restrict development of the dentition and hinders the orthodontic treatment. www.indiandentalacademy.com
    • Causes leading to mouth breathing: • Chronic respiratory obstruction. • Mechanical obstruction. • Size of the nostril. • Pharyngeal tonsils or adenoids (adenoid facies). • Greater effort required to breath through the nose – tortuous nasal passages. • Partial blockage of the nose leads to resistance of airflow – person shifts to mouth breathing www.indiandentalacademy.com
    • Clinical findings of patients with oral respiration : 1. High palate 2. Narrowness of upper arch 3. Crossbite 4. Hyperplasia of the gingiva 5. Adenoid facies 6. Rotation of mandible laterally and backwards. 7. Increased overjet. www.indiandentalacademy.com
    • PATTERN OF FACIAL MORPHOLOGY: The configuration of the facial skeleton and oral respiration are correlated to certain degree. Impeded nasal breathing shows a higher frequency in facial types with vertical growth tendency. Proliferation of the adenoids is more common and more pronounced in patients with oro- nasal respiration. The incidence of hypertrophied tonsils is also increased in this group. Slight proliferation of lymphoid tissue. On upper and rear wall. Marked proliferation occupying half of the pneumatic cavity. www.indiandentalacademy.com Lymphatic tissue occupying most of pneumatic cavity.
    • TONGUE POSTURE: Two different tongue posture are possible in case of oronasal respiration: Type I The tongue is flat and its tip is behind the lower incisors. This type is often encountered on conjunction with a anterior cross bite. TYPE II The tongue is flat and retracted. This type of abnormal tongue posture is common in cases with oral respiration and disto occlusion. www.indiandentalacademy.com
    • EXAMINATIONOF BREATHING MODE: Following are the various clinical methods of examination: 1. Cotton pledget test 2. Mirror test 3. Observation of nostrils www.indiandentalacademy.com
    • DIFFERENTIAL DIAGNOSIS: Differential diagnosis must be used to determine whether the problems in nasal respiration are due to an obstruction of the upper nasal passages or habitual oral respiration. The orthodontic treatment planning for patients with restricted nasal respiration must be related to diagnosis of the ENT specialist. www.indiandentalacademy.com
    • SUPPLEMENTAL FINDINGS The health of oral hard and soft tissues must be assessed for potential orthodontic patients as for any other. It is important that any dental caries or pulpal pathology be treated before orthodontic therapy. A thorough peridontal evaluation is an important part of orthodontic examination. Potential or actual mucogingival problems are of special interest. Any orthodontic examination should include gentle probing through the gingival sulci, not to establish pocket depths but to detect any areas of bleeding. Bleeding on probing indicates active disease, which must be brought under control before other treatment is undertaken. Inadequate attached gingiva around crowded incisors indicates the possibility of tissue dehiscence developing when the teeth are aligned, especially with nonextraction treatment. www.indiandentalacademy.com
    • RADIOLOGIC EXAMINATION www.indiandentalacademy.com
    • RADIOLOGIC EXAMINATION • Radiological examination is absolutely essential in orthodontic diagnosis. In clinical practice, the type and number of radiographs should, subject patient to as little radiation exposure as possible while providing maximal information at the same time. Radiographs of the hands and temporomandibular joints are not among the routine requirements of orthodontic diagnosis.         POSTEROANTERIOR VIEW CEPHALOGRAMS PANORAMIC VIEW ENLARGED PANORAMIC VIEW PERIAPICAL VIEW OCCLUSAL VIEW MENTAL SPINE VIEW TMJ VIEWS www.indiandentalacademy.com
    • POSTEROANTERIOR VIEW: The straight posteroanterior view is so named because the x-ray beam passes in a posterior to anterior direction through the skull. This projection is used to examine the skull for disease, trauma, or developmental abnormalities. It also provides good record for detecting progressive mediolateral dimension changes of the skull, including asymmetric growth. It also offers good visualization of facial structures, including the frontal and ethmoidal sinuses, nasal fossae and orbits. www.indiandentalacademy.com
    • CEPHALOMETRICS Cephalometrics is a tool for dealing with variations in craniofacial morphology. Its purpose is always comparison. In practice these comparisons are made for one of five reasons. 1. To describe morphology or growth. 2. To diagnose anamolies. 3. To predict future relationship. 4. To plan treatment. 5. To evaluate the results of the treatment. 1.DESCRIPTION: Cephalometric description aids in the specification, localization, and understanding of abnormalities. It comprises of three kinds of comparisons. a. comparison with standard. b. comparison with ideal. c. comparison with self. www.indiandentalacademy.com
    • a. Comparison with standard: Research population provide extensive statistics for details of cranifacial morphology and growth. Measures of central tendencymean, median, and mode- are often used as norms with which an individual patient is compared; in this sense, they present “normal” form. b. Comparison with ideals: certain clinicians have also contrived subjective ideals of facial form for use of clinical comparison. The difference between standard and ideal is important. Standards are objective measures stastically derived from populations. Ideals are arbitrary, subjective concepts of facial esthetics represented with numbers. c. Comparison with self: The patient may also be described by cephalometric comparisons with his or her earlier cephalogram. www.indiandentalacademy.com
    • 2. DIAGNOSIS: In orthodontics, diagnosis is determination of significant deviations from the normal. The diagnostic purpose of cephalometrics is to analyze the nature of the problem and to classify it precisely. For instance, cephalometric diagnosis leads to assignment to facial types and classes. Since some aspects of facial morphology are relatively stable under treatment, cephalometric diagnosis contains a strong component of prediction. 3. PREDICTION: Description, diagnosis, and prediction are conceptually and practically quite different. To make a cephalometric prediction is to observe certain quantities, assumes they will behave in determinate ways, and extrapolate the consequences. The clinician would like to be able to predict well several important aspects of craniofacial growth, for example, changes in principal directions of growth, or the cessation of such periods. Therefore, the most practical prediction currently involves the exploitation of “craniofacial constants” to supply predictions of shape approximately independent of net amount of growth remaining. www.indiandentalacademy.com
    • 4. PLANNING TREATMENT: If the clinician can describe, diagnosis, and predict craniofacial morphology, a clear plan of orthodontic treatment can be derived. All treatment occurs after the initial cephalogram in a face which is constantly changing. Clinicians use the cephalogram to define expected changes resulting from growth and treatment is applied prediction. 5. EVALUATION OF TREATMENT RESULTS: Successive cephalogram are used to discern the progress of treatment and to plan any changes in treatment which may seem necessary. Evaluation of treatment results is recurrent description and diagnosis. www.indiandentalacademy.com
    • OBTAINING THE CEPHALOGRAM: A cephalometric apparatus consists of a cephalostat or head holder, an x-ray source, and a cassette holder. Cephalostats are of two types. The BroadbentBolton method utilizes two x-ray sources and two film holders so that the subject need not be moved between the lateral and posteroanterior exposures. Although this method makes more precise three dimensional studies possible, it requires two x-ray heads and more space and it precludes oblique projections. The Higley method used in most modern cephalostats, uses one x-ray source and film holder with a cephalostat capable of being rotated. The patient is repositioned in the course of the various projections. This method is more versitile, but care must be taken so that the horizontal relationship of the head does not alter during reposition. www.indiandentalacademy.com
    • The x-ray sorce must produce sufficiently high voltage (usually above 90 kVp) to penetrate the hard tissue well and to provide good delineation of both hard and soft structures. A small focal spot results in sharper radigraphic images. www.indiandentalacademy.com
    • PANORAMIC VIEW • For orthodontic diagnosis this is superior to all other radiographic methods. One single film provides a total survey of the dental status and adjacent bony structures of both jaws. It involves least exposure to radiation. A disadvantage of this rotary laminographic technique is a possible distortion in the anterior region. Some cases will, therefore, require supplementary radiographs, such as an enlarged panoramic view or periapical view. www.indiandentalacademy.com
    • ADVANTAGES: 1. It provides an over all view of the teeth and the jaws. 2. It serves as a screening projection to identify odontogenic diseases and other disorders that may be the source of TMJ symptoms. 3. Gross osseous changes in the condyles may be identified, such as asymmetries, extensive erosions, large osteophytes, or fractures. 4.Useful aid in serial extraction procedures to study the status of erupting teeth. LIMITATION: No information about condylar position, or function is provided and mild osseous changes may be obscured. DISADVANTAGES: 1. No display of fine anatomic details 2. Unequal magnification 3. Geometric distortion in the anterior region 4. Occasionally presence of overlapping structures of cervical spine www.indiandentalacademy.com
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    • ENLARGED PANOROMIC VIEW • Advantage :- accurate imaging of anterior region • Disadvantage :- distortion in the posterior region PERIAPICAL VIEW Intraoral radiographs are the backbone of imaging. A full series of intraoral radiographs (10 to 16 films) is required for assessment of the periodontal state in adults. Otherwise periapical films are only indicated where the panoramic view suggests possible pathological conditions. (e.g. congenitally missing teeth or malposed tooth germs). www.indiandentalacademy.com
    • USES: 1. To confirm the presence or absence of teeth or supernumerary teeth. 2. To assess the extent of calcification and root formation. 3. To study the alveolar bone and periodontal ligament. 4. To study height and contour of alveolar bone. 5. To assess the axial inclination of roots. 6. To detect retained root fragments and root stumps. 7. To determine the size and shape of unerupted teeth. DISADVANTAGES: 1. Assessment of entire dentition requires much of radiation exposure. 2. Children may not allow placement of films. 3. They cannot be used in patients having high gag reflex and trismus. www.indiandentalacademy.com
    • GLOBULOMAXILLARY CYST www.indiandentalacademy.com
    • ENAMEL PEARL TAURODONTISM www.indiandentalacademy.com
    • FUSION www.indiandentalacademy.com
    • BUCCOLINGUAL SPATIAL LOCATION OF OBJECTS • Mesiocentric periapical view :- X-ray tube angulated at 30 degrees mesial to the perpendicular projection. • Distocentric periapical view :- X-ray tube angulated at 30 degree distal to the perpendicular projection. www.indiandentalacademy.com
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    • OCCLUSAL VIEW • Displays relatively large segment of a dental arch. • Used in following situations :-To precisely locate roots of supernumerary, unerupted, impacted canines and third molars. -Localize foreign bodies in salivary gland ducts. -Location,nature,extent and displacement of fractures. www.indiandentalacademy.com
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    • SAILOLITH FRACTURE www.indiandentalacademy.com
    • MENTAL SPINE/GENIAL TUBERCLE VIEW This is an occlusal view of the anterior section of the mandible to determine its midline 1,2,3 are the individual exposure position. gg- genioglosus. gh- geniohyoid. mh- mylohyoid 1. The double spine of the superior part of the mental spine 2. The unpaired spine of the inferior part as well as the bilateral st. of the superior genial tubercle in the center. 3. 3 bony spines , the bony contours of the inferior genial tubercles . www.indiandentalacademy.com
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    • TRANSPHARYNGEAL PROJECTION: • The tranpharyngeal projection provides a sagittal view of the medial pole of the condyle. Because of the negative beam angulation, this view depicts the medial aspect of the condyle. The transpharyngeal view provides limited diagnostic information because the temporal component is not imaged well. The transpharyngeal projection is effective for visualizing erosive changes of the condyle rather than more subtle changes. www.indiandentalacademy.com
    • TRANSORBITAL PROJECTION: This projection is similar to the transmaxillary projection in that both provide an anterior view of the TMJ, perpendicular to transcranial and transpharyngeal projections. The entire mediolateral dimension of the articular eminence, condylar head, and condylar neck is visible, which makes this view particularly useful for visualizing condylar neck fractures. The morphology of the convex surface of the condylar head can be evaluated, making this projection a useful adjunct to transcranial and transpharyngeal projection in the diagnosis of the gross degenerative changes or other anomalies. www.indiandentalacademy.com
    • TRANSCRANIAL PROJECTION: It provides a sagittal view of the lateral aspect of the condyle and temporal component. Because of the positive beam angulation, the central and medial aspects of the joint are projected inferiorly, and only lateral joint contours are visible in this projection. The transcranial projection is useful for identifying gross osseous changes on the lateral aspect of the joint only, displaced condylar fractures, and range of motion. CLOSED MOUTH www.indiandentalacademy.com OPEN MOUTH
    • SPECIALIZED TECHNIQUES • CONVENTIONAL TOMOGRAPHY. • COMPUTED TOMOGRAPHY. • MAGNETIC RESONANCE IMAGING. • ULTRASONOGRAPHY. • ELECTRONIC THERMOGRAPHY. • ARTHROGRAPHY • FINITE ELEMENT ANALYSIS.. • PALATOGRAPHY. • CINERADIOGRAPHY. • ELECTROMYOGRAPHY. • BONE SCANNING. • LASER SCANNING. • VIDEOCEPHALOMETRY. www.indiandentalacademy.com
    • TOMOGRAPHY: Conventional film-based tomography , also called body section radiography, is a radiographic technique designed to image more clearly objects lying with in the plane of interest. This is accomplished by blurring the images of structures lying superficial and deep to the plane of interest through the process of motion unsharpness. Conventional tomography now is applied primarily to high contrast anatomy, such as that encountered in temporomandibular joint and dental implant diagnosis. This technique produces thin image slices, permitting visualization of an anatomic structures essentially free of superimpositions of overlapping structures. This technique can provides a true condylar position and osseous erosive changes, and is a valuable adjunct to plain film radiography. www.indiandentalacademy.com
    • TOMOGRAM OF TMJ www.indiandentalacademy.com
    • COMPUTED TOMOGRAPHY: Computed tomography is indicated when more information is needed about the three dimensional shape and internal structure of the osseous components of the joint. CT produces digital image slices in both the axial and coronal planes, although coronal images are more useful. Three dimensional reformatted images also can produced. These are useful for assessing osseous deformities of the jaws or surrounding structures. CT cannot produce accurate images of the articular disk.. CT may be considered for determining the presence and extent of ankylosis and neoplasms and the extent of bone involvement in some arthritis, imaging complex fractures, and evaluating complications from the use of silicon sheet implants such as erosions into middle cranial fossa and ectopic bone growth. ADVANTAGE:1. Accurate visualization of an area of interest is possible 2. The computer programming makes it possible to view the images in different shade and densities. 3. CT is useful for diagnosis of diseases in maxillofacial complex, including salivary gland and TMJ. www.indiandentalacademy.com
    • CT SCAN SHOWING LESION IN MANDIBULAR RAMUS AREA. www.indiandentalacademy.com
    • MAGNETIC RESONANCE IMAGING: MRI uses a magnetic field and radiofrequency pulses rather than ionizing radiation to produce multiple digital image slices. To produce an MR image, the patient is placed inside a large magnet, which induces a relatively strong external magnetic field. This causes the nuclei of many atoms in the body, including hydrogen to align themselves with the magnetic field. After application of an RF signal, energy is released from the body, detected and used to construct the MR image by computer. MRI has several advantages over other diagnostic imaging procedures. 1. It offers the best resolution of tissues of low contrast. 2. No ionizing radiation is involved. 3. The region of the body imaged in MRI is controlled electronically so a direct multiplanar imaging is possible without reorienting the patient. 4. In diagnosing a suspected internal derangement of the TMJ and evaluating the treatment of that derangement after surgery; identifying and localizing orofacial soft tissue lesions; and providing images of salivary gland parenchyma. www.indiandentalacademy.com
    • ADVANTAGES: MRI does not have hazards as it uses non-ionising electromagnetic radiation. Anatomical details are as good as in C.T. scan. Imaging of blood vessels, blood flow, visualization of thrombus is possible. DISADVANTAGES: Time taken is more. It is not used in patients with cardiac pacemaker. Non visualization of bone makes it useless in bony lesions. www.indiandentalacademy.com
    • MRI OF TMJ www.indiandentalacademy.com
    • ULTRASONOGRAPHY: By definition, ultrasound has a periodicity greater than 20 KHz. Thus it is distinguished from other mechanical waves forms simply by having a vibratory frequency greater than the audible range. As the ultrasonic beam passes through or intersects with tissues of different acoustic impedance, it is attenuated by a combination of absorption, reflection, refraction, and diffusion. These sonic echo waves are reflected back to transducer which are amplified, processed, and ultimately displayed on the monitor. Consequently, not only changes in echo pattern delineate different tissues, they also can be correlated with pathologic changes in a tissue. Differentiation between a cyst and tumor can be done and in visceral and somatic swallowing patterns. www.indiandentalacademy.com
    • Ultrasound image showing parasagittal image of the TMJ area showing the articular disk in its normal location superior to the condyle in the closed mouth position. www.indiandentalacademy.com
    • ELECTRONIC THERMOGRAPHY: Thermography is a term given to methods of temperature pattern resolution and analysis. The utility of thermography in diagnosis is based on the fact that disease process and abnormal conditions may result in different temperature patterns because of altered blood supply or presence of inflammation. 1. Diagnosing disease of the maxillofacial complex. 2. Determining tooth vitality. 3. Evaluating a case of atypical odontalgia 4. Assessing an internal derangement of the TMJ. www.indiandentalacademy.com
    • ARTHROGRAPHY: Arthorography is a technique in which an indirect image of the disk is obtained by injecting a radiopaque contrast agent into one or both joint spaces under fluoroscopic guidance. A perforation is detected by the flow of contrast agent into the superior joint space from the lower space, and adhesion are detected by the manner in which contrast agent fills the joint space. After the joint space is filled, disk function is studied using the fluoroscopy during the opening and closing movements. Arthorgraphy is indicated when information about Disk position, function, morphology and the integrity of the diskal attachment is required. The risk of this procedure include allergic reaction to the nonionic iodine contrast agent and infection. www.indiandentalacademy.com
    • FINITE ELEMENT METHOD: Albeit initially developed this methid for aeronautical engineers, the finite has found its place in medical and dental research over the last few years. It was originally developed for studying the stresses in the complex air frame. It can also be used for vibration analysis, thermodynamic analysis, fluid flow and distribution of electric and magnetic fields. The application of FEM most related to orthodontics is the structural stress analysis. There is a plethora of studies in orthodontic literature using the FEM. These include studies of wire configuration, stresses in the periodontal ligament, determination of centers of resistance and rotation of teeth with normal or reduced bone height, stresses on TMJ, jaws and cranium, stresses in brackets and adhesives, design of ceramic brackets and studies of craniofacial growth. www.indiandentalacademy.com
    • DIGITAL CINERADIOGRAPHY: PRINCIPLE: Using flash x-ray sources, gated cameras are triggered simultaneously with each x-ray source in succession at the rate desired. The gated cameras can be set for exposure times between 5 nanoseconds and 33 milliseconds. In cineradiography, the idea is to freeze motion in a series of images to track motion in discrete steps. It helps in recording motion of dynamic events like swallowing pattern. LIMITATIONS: The images captured by digital cameras that have poorer spatial resolution than that of film. www.indiandentalacademy.com
    • Cineradiography showing various steps involved in swallowing. www.indiandentalacademy.com
    • ELECTROMYOGRAPHY: Electromyography is a medical technique for evaluating and recording physiologic properties of muscle at rest and while contracting. EMG is performed using a instrument called an electromyograph, to produce a record called an electromyogram. An electromyograph detects the electrical potential generated by muscle cells when these cells contract and also when cells are at rest. • Structural basis of Emgram is – motor unit. • Electrical potential developed by the activation of one motor unit is called – motor unit potential. • Lasts for 5 to 8 milli sec and has an amplitude of 0.5 mv. • EP recorded from whole muscle shows smaller potentials if the force of contraction is less. • When force is increased,due to recruitment of more & more number of motor neurons,larger potentials www.indiandentalacademy.com are obtained.
    • USES: 1. Helps to distinguish primary muscle conditions from muscle weakness caused by neurologic disorders. 2. It is used to find causes of muscle weakness, hyperactivity, paralysis, involuntary twitching, and abnormal levels of muscle enzymes. 3. In severe class II Div. I cases the upper lip is hypofunctional. Thus during swallowing, the lower lip extends upwards and forwards to force the maxilla labially and a strong mentalis activity is seen. EMG can be used to study such condition. 4. Abnormal buccinator activity in class II malocclusion. 5. Overclosure of jaws is associated with accentuated temporalis muscle activity. 6. Children with cerebral palsy. 7. EMG can be carried out after orthodontic therapy to see if muscle balance is achieved. www.indiandentalacademy.com
    • XERORADIOGRAPHY: Xeroradiography was invented by Chester F. Carlson in 1937. xeroradiography employs reusable photoreceptor plate and ultimately produces an image on paper. xeroradiographic head films is used for routine cephalometric analysis. A xeroradiographic picture or print resembles a blue print, but it shows all tissue densities with fine detail. Xeroradiography is primarily used for evaluation of breast lesion, larynx and temporomandibular joint. CLINICAL ADVANTAGES: 1. It can be viewed without transillumination. 2. It is not necessary to make the typical cephalometric planes and points be traced and subsequent tracings paper applied directly over the original head film thereby reducing tracing error. 3. All densities of soft and bony tissue are displayed in one picture 4. Intraosseous detail and soft-tissue boundary definitions are superior to the conventional radiograph 5. Teeth are more readily visualized. www.indiandentalacademy.com
    • BONE SCANNING: A bone scan looks for abnormalities in the bone and joints. The scan uses a large camera called a ‘GAMMA CAMERA’. This camera picks up radioactivity. First the radioactive substance is injected into the blood stream and radioactive substance should be small amount, not enough to harm. The radionuclide travels through the blood and collects in bones and more of it collects in areas where there is lot of activity in bone. Activity means the bone breaking down or repairing it self. These areas are picked out by camera and commonly called spots www.indiandentalacademy.com
    • LASER SCANNING: Laser scanning provides a method of capturing the face for planning or evaluating outcome of orthodontic or orthognathic treatment. The scanning is performed using the Vivid 700 (Minolta, resolution : 400*400 pixels), a 3-dimensional scanner operating on a laser-light stripe triangulation range-finder principle. The patient is instructed to sit still in a chair with facial muscles relaxed and eyes and lips lightly closed for 0.6 second during the scanning( 1.0 m apart from scanner, www.indiandentalacademy.com
    • Benefits: 1) An accurate evaluation of pre- and post-treatment soft tissue facial profile is possible. 2) The pre- and post-treatment superimposition provided visualization of the treatment results. 3) A quantitative assessment of the soft tissue changes were possible with the use of the color coding system. 4) The soft tissue facial profile could be evaluated in any direction. 5) Much more diverse information and measurements could be obtained curved surface, volume, etc 6) Excellent & very easy & fast data acquisition was possible. 7) The accurate data could be used for resolution of medical disputes. www.indiandentalacademy.com
    • LIMITATIONS: 1. Safety related issues. 2. Inability to capture the soft tissue texture, which results in difficulties in identification of landmarks. www.indiandentalacademy.com
    • VIDEOCEPHALOMETRY: Computerized videoimaging technology offers a mutual visual template by which orthodontist can effectively communicate with patients, it also allows greater potential for quantification of treatment plans which maximize chances of delivering proposed treatment plan. In other words, coordination of calibrated profile images permits precise measurements of bony and dental movements, and through the application of algorithmic prediction ratios, images are produced that express the expected surgical and orthodontic outcome. Requirements are same of radiographic cephalometry plus control of magnification or distortion introduced by hardware (i.e. camera, monitor, software and cephalograms). USES: 1. Counseling of patient. www.indiandentalacademy.com
    • 2. Treatment planning: The purpose of calibrating the cephalogram to the profile video is: a. Relate the underlying hard tissue to the overlying soft tissue. b. Allow quantification of movements. By knowing where the teeth are in relation to the face, judgments can be made about the basic changes needed for the occlusal correction. Consideration can then be given to what other procedures may be needed for the esthetic ideal. c. Permit the treatment plan to be designed to match the patient’s wishes as closely as possible d. Allows realistic movements to be planned. www.indiandentalacademy.com
    • BIBILOGRAPHY: 1. ORTHODONTIC DIAGNOSIS- RAKOSI 2. DENTOFACIAL ORTHOPEDICS – GRABER, RAKOSI AND PETROVIC 3. RADIOGRAPHIC CEPHALOMETRY- ALEXANDER JACOBSON 4. FUNDAMENTALS OF OCCLUSION AND TEMPOROMANDIBULAR DISORDERS- J.P. OKESON 5. CONTEMPORARY ORTHODONTICS- W.R. PROFFIT 6. ORAL RADIOLOGY- WHITE AND PHAROAH 7. HANDBOOK OF ORTHODONTICS- ROBERT E. MOYERS 8. CURRENT PRODUCTS AND PRACTICES IN ORTHODONTICS – M.Y. HAJEER AND MILLET (journal of orthodontics vol.31 2004) 9. ELECTROMYOGRAPHY AND ITS APPLICATION IN ORTHODOTICS- MEENAKSHI IYER. CURRENT SCIENCE VOL. 80, 2001. 10. CURRENT PRINCIPLES AND CONCEPTS-- GRABER AND VANRASDALL www.indiandentalacademy.com
    • IF WE COULD KNOW WHERE WE ARE AND WHITHER WE ARE TENDING, WE COULD BETTER JUDGE WHAT TO DO AND HOW TO DO IT -ABRAHAM LINCOLN www.indiandentalacademy.com