BIOMECHANICAL CONSIDERATIONS IN OPEN BITE
INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
CONTENTS Introduction. Definition. Types Of Vertical Malocclusion. Overview Of Open Bite. Etiologic Consideration. Esthetic Consideration. Functional Consideration Clinical Consideration Cephalometric Critera www.indiandentalacademy.com
Examination of Oro-Facial Dysfunction –Swallowing –Tongue-thrust –Cheek Dysfunction –Mouth Breathing Equilibrium Theory Influence Of Naso-respiratory Function Long Face Syndrome
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The Association Between Anterior Open–Bite and Amelogenesis Imperfecta Treatment In Primary Dentition Treatment In Mixed Dentition Various Functional Appliances For Treatment Of Open Bite Treatment In Permanent Dentition Conclusion.
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Introduction 1. What is an open bite? 2. The diagnostic criteria of open bite require 3. 4. 5.
clarification? What are we talking about as we loosely use the descriptive term open bite? Is it just a variation on another theme-a variable of the dental occlusion? Is it a separate clinical entity in which the openness between the upper and lower teeth is the only factor involved?
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Etiologic factors related to open-bite must precede any
discussion of clinical treatment Successful orthodontic therapy usually requires a careful appraisal of etiological factors. Unfortunately, it is not always possible to remove factors that have caused or contributed to existing malocclusion. Unfavorable growth or genetic determinants of a malocclusion, including open-bite cannot be altered or removed successfully.
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DEFINITION 1. 2. 3.
Description of open-bite differ among various authors and investigators. Open-bite to be present when there is less than an average overbite. Open-bite to be present when there is edge-to edge relationship. Open-bite to be present when there is definite degree of openness must be present.
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Open-bite must be considered as a deviation in the
vertical relationship of the maxillary and mandibular dental arches. In an open-bite there should be a definite lack of contact, in the vertical direction, between opposing segments of teeth. The degree of openness can vary from patient to patient, but an edge-to-edge relationship or some degree of overbite cannot be rightfully categorized as an open-bite. The loss of contact, in the vertical direction, of segments of teeth can occur between the anterior segments or between the buccal segments. segments
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TYPES OF VERTICAL MALOCCLUSION
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TYPES OF VERTICAL MALOCCLUSION Problems in the vertical dimension includes open bite and deep bite malocclusion and also facial disfiguration. Some problems can be divided into those that are limited to the dentoalveolar area and those that predominantly are of skeletal nature. Dentoalveolar Skeletal
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Open / Deep Bite Hypo / Hyper divergent (Short / Long face syndrome) www.indiandentalacademy.com
If only dentoalveolar structures are involved, the terms open bite and deep bite are used. If skeletal structures are involved, the types of vertical facial patterns can be described as hyperdivergent and hypodivergent. These vertical dysplasias clinically have been termed long face syndrome and short face syndrome. Generally, facial patterns with a mandibular plane angle greater than 300 are considered hyperdivergent, and less than 200 hypo divergent.
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Differentiation Between Skeletal & Dentoalveolar Malocclusion Skeletal open bite as a result of increased downward and backward inclination of the mandible. The mandibular angle is increased.
Open bite of dentoalveolar origin as a result of underdevelopment anteriorly of the maxillary and mandibular alveolar processes.
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OVERVIEW OF OPEN BITE
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Overview of Open Bite Non-Occlusion 1. Traditionally open bite = “opposing teeth do not meet�. 2. Vander Linden, however, has indicated that the 3. 4.
overlap criterion is arbitrary and is associated with the sagittal relation between the teeth involved. The absence of an Occlusal stop between the teeth with their antagonists or opposing gingiva is of greater significance. Absence of such a stop means that the eruption process has been arrested by one or more factors.
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5. The same view was expressed by Moyers, who stated that it is most important to use the term “open bite” for all conditions characterized by the absence of an Occlusal stop. 6.
In the international literature, however, this recommendation has not been implemented, and the term ‘open bite” still is used only for conditions without vertical overlap.
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7. The recently published Glossary of orthodontic Terms defines non-occlusion as any situation in which the teeth do not have maximum contact with their antagonists in habitual occlusion. 8. Anterior non-occlusion Occurs in the incisor area and usually is associated with some degree of overlap of the incisors, as observed often in patients with Class II, division 1 malocclusion. 9. Posterior non-occlusion can occur in the premolar or molar region, with great variation occurring in the number of teeth and the Occlusal surfaces involved.
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10. Total non-occlusion, the tongue is positioned between the opposing teeth most of the time. 11. Non-occlusions are more common than open bites. That holds true for the anterior and posterior regions.
When asked to close the teeth together.
Habitual positioning of Tongue
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ESTHETIC CONSIDERATIONS
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ESTHETIC CONSIDERATIONS 1. Balance between the nose, lips, and chin profile is essential for optimal esthetics.
2. The nasolabial angle also is important.
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3. The dentoalveolar open bite malocclusion is esthetically unattractive particularly during speech when the tongue is interposed between teeth and the lips.
4. The lower facial third is elongated in patients with skeletal open bite.
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FUNCTIONAL CONSIDERATION
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FUNCTIONAL CONSIDERATION 1. Tongue posture and function should be primary considerations in Open-bite problems.
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Acc. To Proffit “if a patient has a forward thrusting posture of the tongue the duration of this pressure even if very light could affect tooth position vertically or horizontally”.
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2. Differentiation between primary causal and secondary adaptive or compensatory tongue dysfunction is essential.
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Acc. to Proffit “A tongue thrust swallow is a useful physiologic adaptation if you have an open bite, which is why an individual with an open bite also has a tongue thrust swallow” (i.e. Secondary adaptive tongue dysfunction)
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According to Bahr and Holt, four varieties of tongue thrust may be differentiated: 1. Tongue thrust without deformation:-
Despite the abnormal function, no deformations ensues.
2. Tongue thrust causing anterior deformation:- i.e anterior open bite, sometimes coupled with bilateral narrowing of the arch and a posterior crossbite. Moyers (1964) terms this a simple open bite.
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3. Tongue thrust causing buccal segment deformation:-
4.
with a posterior open bite is often seen clinically. Lateral tongue thrust activity also can be responsible for a functional deep bite, a variation of the posterior open bite. Some Class II, division 2 malocclusion fit this category. Invagination of the cheek into the interocclusal space also may be a factor in this dysfunction. Combined tongue thrust:- causing both an anterior and a posterior open bite, is another common dysfunction. This is called a complex open bite by Moyers and is more difficult to treat.
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According to Rakosi, four varieties of open bite due to tongue posture may be differentiated: 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 positioned forward during functioning, thus impeding the vertical development of the dentoalveolar structures around the upper and lower anterior teeth. www.indiandentalacademy.com
Lateral Openbite Occlusion, In this type of open bite the occlusion on both sides is supported only anteriorly and by the first permanent molars. Habitual Position The tongue thrusts between the teeth laterally. The tongue dysfunction occurs in conjunction with a disturbance in the physiologic growth processed around the first and second deciduous molars. www.indiandentalacademy.com
Complex open bite: Severe vertical malocclusion. The teeth occlude only on the second molars. Habitual Position Tongue-thrusting occurs during function.
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Tongue dysfunction and malocclusion: In mandibular prognathism, the downward forward displacement of the tongue often causes an anterior tongue-thrust habit.
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CEPHALOMETRIC CRITERIA
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Cephalometric Criteria A proper cephalometric analysis enables a classification of open bite malocclusions:
1. Dento Alveolar Open Bite. 2. Skeletal Open Bite.
3. 4.
1. Positional Deviations. 2. Dimensional Deviations Skeletal Class II Open Bite Skeletal Class III Open Bite
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Dento alveolar open bite 1. The extent of the dentoalveolar open bite depends on the extent of the eruption of the teeth.
2. Supraocclusion of the molars and infraocclusion of the incisors can be primary etiologic factors.
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3. In vertical growth patterns the dentoalveolar symptoms include a protrusion in the upper anterior teeth with lingual inclination of the lower incisors.
4. In horizontal growth patterns, tongue posture and thrust may cause proclination of both upper and lower incisors.
5. A lateral open bite may be considered dentoalveolar in combination with infra-occlusion of molar teeth.
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Vertical growth pattern associated with anterior tongue dysfunction In Vertical growth pattern, tongue thrust tends to tip the upper incisors to the labial and the lower incisors to the lingual.
• protrusion in the upper anterior •
teeth with lingual inclination of the lower incisors. over eruption of posterior teeth and steeper than normal mandibular plane www.indiandentalacademy.com
Horizontal growth pattern associated with anterior tongue dysfunction Horizontal growth pattern, tongue thrust causes bimaxillary dental protrusion, i.e. labial tipping of upper and lower anterior teeth.
The incisor relationships in a case with an anterior open bite, tongue-thrust, and horizontal growth pattern
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Skeletal Open Bite 1. Dysgnathia with a vertical growth 2.
3.
pattern The downward and backward rotation of the mandible is the cause of the anterior open bite. The gonial angle and its lower segment are markedly enlarged. The clinical picture of the open bite is partly compensated by the linguo-version of the upper anterior teeth. www.indiandentalacademy.com
Skeletal Open-Bite 1. Positional deviations. 2. Dimensional deviations.
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Positional Deviations Acc to Sassouni‌ 1. The four bony planes of the face are steep to each other, bringing the center 0 close to the profile. 2. The anterior arc, therefore follows the convexity of the profile. diagram
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3. The posterior vertical chain of muscles is arcuate, and the masseter muscle is posterior to the buccal teeth, thus creating a mesial component of forces responsible for the dental protrusion.
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4. The cranial base angle and the gonial angle are obtuse.
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5. The long axis of the incisors forms a small interincisal 6.
angle. Although the incisors are usually more extruded in the open-bite type, this extrusion is not sufficient to establish their vertical contact.
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Dimensional Deviations 1. The total posterior facial height (S-Go) tends to be half 2. 3. 4. 5.
the size of the anterior total facial height (N-Me). The lower anterior facial height exceeds the upper anterior facial height. The facial breadths tend to be narrow, giving a long, ovoid appearance in the frontal view. The nasal apertures are narrow. The ramus is short with an antegonial notch at its lower border.
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6. The mandible seems to have retained its infantile characteristics, with all its processes underdeveloped. 7. The temporal fossa is small, suggestive of weak musculature. 8. The mandibular symphysis is narrow antero posteriorly and long vertically. 9. There is a lack of chin mental protuberance development. 10.The cranium is sometimes dolichocephalic.
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11. According to the Sheldonian somatotyping, the open12. 13. 14. 15.
bite type rates high in ecto-morphs. Proportionally large teeth characterize the dentition. Crowding and bi-dental protrusion are often present. Impaction or ectopic eruption of third molars is frequent. The palatal vault is high and narrow.
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16. The mouth is wide. The broad lips, short vertically 17.
relative to their skeletal support, are kept apart at rest, leading to mouth breathing. When the lips are forcibly closed, the mentalis muscle is displaced upward. This further increases the “chinless� appearance of these persons.
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SKELETAL CLASS II OPEN BITE 1. This combination is primarily an open-bite type, 2. 3. 4.
positionally and dimensionally. The major variant here is in the antero-posterior dimensions of the jaws. The palate may be longer, and the mandible shorter. The differential evaluation of these two possibilities is important, as the prognosis and the treatment approach may be different. In this respect, it points out that a given dental Class II malocclusion may be present in opposite facial types.
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5. In this type, in some instances, the rotation of the 6.
mandible may be purely positional. Often this is due to a downward and backward rotation of the mandible. This rotation is associated with excessive extrusion of the molars. If these interferences were removed, the mandible could be permitted to rotate in a closing direction, improving the Class II and the open-bite patterns simultaneously.
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SKELETAL CLASS III OPEN BITE 1. This combination consists primarily of an open-bite with 2. 3.
a palatal deficiency or a large mandible. Among the facial deformities, these have probably the worst prognosis in terms of dentofacial orthopedics. If correction of this open-bite is attempted by rotating the mandible in a closing direction, the protrusion of the chin is increased.
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4. On the other hand, the reduction of the mandibular 5.
protrusion is attempted by rotating the mandible downward and backward, the open-bite is increased. Even surgical correction of the mandible is of limited benefit here, as the teeth interfere in the closing of the lower face height.
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SKELETAL OPEN BITE
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SKELETAL FACTORS IN THE DEVELOPMENT OF AN OPEN BITE TYPE:
1. The posterior half of the palate is tipped downward, 2.
carrying the molars further downward. This gives rise to a large palatomandibular plane angle. The combination of an excessive development of the upper mid-face heights (cranial base to molars) and a lack of development of posterior facial heights (S-Go) results in the downward and backward rotation of the mandible.
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3. Because of the short ramus and the lower palate, the
4.
pharyngeal space is constricted. In order to breathe, these persons keep their tongues forward. Further enhanced by the dental open-bite, there is a tonguethrusting tendencies. When enlarged tonsils are present, the tongue is further confined anteriorly. As the narrow palatal vault reduces the necessary space, there is a tendency toward tongue protrusion. This, in turn, may be a factor in the creation of bi-dental protrusion.
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Various Forms Of Anterior Open Bite
1. An overjet combined with an open bite of less than 1mm 2. 3.
can be designated as pseudo-open bite problems. A simple open bite exists in cases in which more than 1 mm of space may be observed between the incisors, but the posterior teeth are in occlusion. A complex open bite designates those cases in which the open bite extends from the premolars or deciduous molars on one side to the corresponding teeth on the other side.
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4. The compound or infantile open bite is completely 5.
open, including the molars. The iatrogenic open bite is the consequence of orthodontic therapy, which produces atypical configurations because of appliance manipulation or adaptive neuromuscular response.
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Clinical assessment of dental open bite 1. The Glossary of Orthodontic Terms defines open bite as
2. 3.
a developmental or acquired malocclusion whereby no vertical overlap exists between maxillary and mandibular anterior or posterior teeth. the latter are caused by tongue interposition or by disturbances in eruption (e.g ankylosis). Posterior open bites rarely are due to primary failure of eruption. Defects in eruption often are associated with various craniofacial syndromes, including cleidocranial dysplasia and Carpenter’s syndrome.
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4. An open bite without facial disfiguration is classified as
5.
a dental open bite and frequently is classified as dental open bite and frequently is associated with a digital sucking habit and / or tongue interposition. The characteristics of a dental open bite include problems typically restricted to the anterior teeth and immediately associated hard and soft tissue structures without remarkable cephalometric findings.
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Vertical Malposition Vertical malpositioning of groups of teeth is judged in relation to the occlusal plane.
“Infraversion” or “infraocclusion” indicates that teeth have not yet reached the level of the occlusal plane.
This malpositioning usually occurs in conjunction with irregularities in the vertical development of the alveolar process.
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Correct vertical relation of the anterior and posterior teeth to the occlusal plane (the imaginary plane passes through the tips of the premolar cusps and is perpendicular to the tuberosity plane).
Infraversion of the upper anterior teeth in conjunction with an underdeveloped anterior alveolar process (Korkhaus, 1939).
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Infraocclusion Of The Anterior Teeth Open bite malocclusion; the upper incisors do not reach the occlusal plane. The alveolar process is noticeably undeveloped in the anterior region.
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Clinical assessment of skeletal open bite 1. An open bite associated with divergence of the skeletal 2.
planes is term as skeletal open bite or apertognathia. characteristics of a skeletal open bite include a) increased lower anterior facial height, b) increased total anterior facial height, c) increased gonial, mandibular plane and Occlusal plane angles, d) decreased palatal plane angle, e) occasional maxillary retrognathia, and f) increased vertical maxillary and mandibular dentoalveolar dimensions.
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3. Extreme skeletal open bite often are associated with craniofacial malformations, such as the Crouzon’s syndrome patient, in whom there are gross imbalances in skeletal structures in all three dimensions of the face.
4. These types of problems are addressed only with craniofacial surgery, including distraction osteogenesis.
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5. Proffit and colleagues note that, although increased
6. 7.
lower anterior facial height exacerbates the problem by adding a skeletal element, about one-third of patients seeking surgical correction of long-face syndrome have a normal or excessive overbite, rather than an open bite, this type of occlusion is an indication of the compensatory dental eruption that can occur in these patients. This illustrates that the long face syndrome and the dental open bite are different entities. Indeed, the facial disfiguration seen in skeletal open bites can be found without the presence of dental open bites; however, most instances, skeletal open bite is combined with dental open bite. www.indiandentalacademy.com
The morphology of the facial skeleton and the effects of tongue-thrusting are correlated to a certain degree. In a vertical growth pattern with tongue-thrust the lower incisors are often in lingual inclination. From the differential diagnostic point of view, it is important to clarify both the skeletal relationships and the tongue dysfunction in order to localize the results of the abnormal tongue functioning.
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Equilibrium exists when a body at rest is subjected to
forces in various directions, but is not accelerated. Malocclusion of the teeth and the broader spectrum of dentofacial deformity is due, to an interplay between innate genetic factors and external environmental factors. The environment of the teeth and alveolar bone includes conflicting forces and pressures, primarily from muscular function, which in part determine tooth position. The more important these forces on the teeth are conceived to be, the more one takes an environmentalist view as far as the cause of malocclusion is concerned.
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The more one believes in inherited causes for
malocclusion, the less attention he is likely to pay to the environment of the dentition. During mastication’s not only do the teeth move slightly but the alveolar bone and the basal bone of maxilla and mandible bend and flex. These changes occur in a matter of seconds, and the teeth and jaws are restored to their original positions as quickly as they were displaced. Natural dentitions are stable over a time span of years after growth is completed.
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Angle felt that relapse after orthodontic treatment was
due to forces on the teeth resulting from an improper environment. It is difficult even today to disagree with that view. The French molecular biologist “Jacob” quotes an earlier physicist, “however, there is always a desire in science to ‘explain the complicated visible by some simple invisible”. Tongue pressure, lip pressure, pressure from erupting third molars all make nice “simple visible” causes for orthodontic relapse.
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Four Major Factors In The Dental Equilibrium 1. Intrinsic forces by tongue and lips. 2. Extrinsic forces: habits (thumb-sucking, etc), orthodontic 3. 4.
appliances. Forces from dental occlusion. Forces from the periodontal membrane.
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Intrinsic Forces By Tongue And Lips
1. The teeth are positioned between the lips and cheeks on one side and the tongue on the other, the opposing force or pressures from these organs should be major determinants of the dental equilibrium.
2. A superficial consideration of the dental equilibrium requires that a distinction be made between the amount of force generated against a tooth and the duration of force application.
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3. Wave of enthusiasm was triggered by Walter Straub in the 1950’s after he had decided from clinical observation that incorrect swallowing was a major cause of anterior open bite and incisor protrusion.
4. Tongue and lip pressures during swallowing never balanced.
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5. It seemed logical that patients who swallowed 6. 7. 8.
incorrectly should have protruding incisors or open bite because of different tongue and lip pressures. Investigators quickly noted that tongue pressures during swallowing always are several times higher than the lip or cheek pressure which should balance them. When time–pressure integrals are compared, tongue and lips come closer to balance, but tongue pressure is still considerably greater than lip pressure. There is no balance of pressures for swallowing.
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8. The dental apparatus is well-adapted to resist shortacting forces such as those generated during chewing, speaking and swallowing, where the duration of force application is typically one second or less.
9. Only resting pressures of tongue and lips should be considered as factors in the equilibrium.
10.This was and is a most reasonable suggestion, yet resting pressures do not balance.
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EXTRINSIC FORCES (External Pressure Habits and Orthodontic Appliances)
1. All clinical orthodontics is based on moving teeth by 2. 3. 4.
deliberately altering the force equilibrium on the dentition. Teeth can be moved effectively by a force of only a few grams provided that the force is maintained continuously. The duration of force is a more critical variable in orthodontic treatment than force magnitude. The same is true for external pressure habits, such as thumb sucking.
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Thumb Sucking
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5. The greater the duration of the habit, the greater its impact on the teeth is likely to be. For both orthodontic appliances and habits, durations must be measured in hours per day to produce significant changes in tooth position.
6. Extrinsic forces can be quit effective when their duration approaches fifty percent of the time, and some impact apparently can be produced by durations of only a few hours.
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7. The discussion has related largely to tooth position in the anterior, posterior and transverse planes of space. What about the vertical plane of space, vertical tooth position certainly can be influenced by environmental factors.
8. Wallen indicate that vertically directed pressures during swallowing actually are less in patients with anterior open bite than in patients with normal vertical relationships.
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9. The tongue pressures were greater in the open bite patients than in the normal occlusion patients, it would be easy to understand how the tongue was preventing eruption.
10.If the pressures were the same in open bite or normal occlusion, one could say that the teeth were being impeded by this pressure and held at a higher level.
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11.It appears that the relatively high position of the incisors keeps the tongue from contacting them quite so much during swallowing. This does not support the idea that tongue placement during swallowing causes open bite. Certainly forward tongue position during swallowing, which usually is called tongue thrust, is associated with open bite but it seems more likely to be effect than cause.
12.Jaw posture, occlusal force, and eruption force from the periodontal membrane must be considered.
13.Other factors which come to mind immediately are forces of occlusion and forces of eruption. www.indiandentalacademy.com
FORCES FROM DENTAL OCCLUSION 1. The attachment apparatus of all teeth is an effective
2.
3.
hydrodynamic damping system, like an automobile shock absorber and is well designed to withstand occlusal forces. The teeth would make minor corrections of themselves. This does happen just after the completion of orthodontic treatment, when the teeth are hyper mobile and the attachment apparatus is reorganizing. It is common experience that teeth remain in positions of traumatic occlusion rather than moving away from the offending occlusal contacts.
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4. The mechanism to dissipate short- duration Occlusal
5.
6.
forces so that teeth do not permanently intrude or move buccally or lingually because of occlusal forces, occlusal forces can be important in equilibrium related to vertical tooth position. The vertical position of the teeth is determined by a balance between the forces which oppose eruption and those which promote it. Occlusal forces have an influence related to this. Numerous studies of occlusal forces it is known that a maximum force of one hundred kilograms or more sustained for only a fraction of a second can be exerted against a single tooth during occlusion.
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7. If the molar teeth are extruded by orthodontic forces,
8.
the mandible will rotate downward and backward as the Occlusal contact and rest positions change. Once a natural tooth has erupted or been extruded, the musculature adapts to its position. Mandibular positioning during growth influences eruption and the final vertical position of the teeth remains entirely unknown. Occlusal forces during growth probably play a significant role.
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FORCES FROM THE PERIODONTAL MEMBRANE:- ERUPTION FORCES 1. An eruption force is generated which moves a tooth through bone and continues to move it after it has broken into the oral cavity. The eruptive force remains active after a tooth has come into occlusion and function has been established.
2. Eruption continues along with vertical growth of the face e.g. a maxillary first molar typically erupts for a centimeter or between age six when it first comes into occlusion and the time in the late teens when vertical jaw growth ends. www.indiandentalacademy.com
3. If its antagonist is extracted, any tooth may erupt again years after its vertical position apparently was stable, indicating that the eruptive mechanism remains intact and capable of generating forces which can move a tooth.
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Tooth eruption theories can be divided into three major groups: 1. Theories based on cell proliferation at the root apex 2. Theories based on blood pressure- blood flow 3.
differentials in the periodontal membrane Theories based on metabolic change sin the periodontal membrane, usually involving collagen polymerization.
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The weight of present evidence indicates that eruptive forces are generated in the periodontal membrane rather than at the root apex, but exactly how remains unclear. Tongue and lip pressures to produce a very sensitive and highly stable transducer, which can be placed against the tip of an erupting incisor.
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INFLUENCE OF NASORESPIRATORY FUNCTION
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INFLUENCE OF NASORESPIRATORY FUNCTION
1. Cause of vertical dysplasia is deviating neuromuscular 2.
3.
function associated with an abnormal breathing pattern. Physiologic adaptations to various types of upper respiratory obstruction (eg constricted external nares, deviation septum, nasal polyps enlarged adenoids, enlarged tonsils) initially may lead to altered functional activity of the muscles associated with respiration. It is hypothesized that this change in the level of postural activity of certain craniofacial muscles ultimately may lead to a change in craniofacial morphology, particularly in the vertical dimension.
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4. Changes in the level of level of activity of certain 5. 6. 7.
craniofacial muscles leads to an extension of the head and airway maintenance. This alteration causes a stretching of the masticatory and facial muscles as well as the associated soft tissue. A prolonged obstruction of the airway can lead to skeletal remodeling and ultimately a change in craniofacial morphology. The possible relationship between airway obstruction and aberrant craniofacial growth is the type of patients descried as having ‘adenoid facies.’
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8. These patients typically present a mouth- open posture, a small nose with button like tip, nostrils that are small and poorly developed, a short upper lip, prominent maxillary incisors, a putting lower lip, and a vacant facial expression. 9. ‘Mouth-breathing� individuals classically have been described as possessing a narrow, V-Shaped maxillary arch, a high palatal vault, proclined maxillary incisors, and a Class II occlusion. 10.Patients who have severe allergies often presents with similar facial manifestations. In addition, they may have what are termed allergic shiners’ which represent a pooling of blood under the eyes, a sign of the allergic response. www.indiandentalacademy.com
Examination of Orofacial Dysfunctions
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Examination of Orofacial Dysfunctions Swallowing Tongue Speech Lips Respiration
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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 simple thrusting action
Tongue-thrust syndrome
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The following symptoms distinguish Tongue Thrust Syndrome:
1) Protrusion of the tip of the tongue . 2) No contact of the molars. 3) Contraction of the perioral muscles during the ďƒ˜ ďƒ˜
deglutition 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.
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Tongue peristalsis during somatic swallowing: I Collecting stage II Transporting stage - Ist part of movement 2nd part of movement 3rd part of movement III Third swallowing stage IV Fourth swallowing stage V Final stage
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Collecting Stage – The 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
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Transporting stage Ist 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 (according to Graber, 1972).
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Transporting stage 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.
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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.
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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 palatopharygeal seal and close the nasopharynx. The teeth are in full occlusion and the lips in contact.
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Fourth Swallowing Stage: During the fourth sage 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.
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Final Stage Of Swallowing Cycle: Once the swallowing act has been completed, the mandible returns to its rest position.
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Visceral (Infantile) Swallow In The Neonate The jaws are apart during swallowing. The tongue is pushed forward and placed between the gum pads. The tip of the tongue protrudes. The mandible is stabilized by the contraction of the tongue and the oro-facial musculature as well as by the tongue contact with the lips.
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Swallowing is triggered off and, to a large extent, carried out by sensory interchange between the lips and the tongue. Peristalsis already commences in the vestibule. The transverse section shows that the tongue is positioned low in the mouth and that the central furrow is depressed (according to Graber, 1972).
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Somatic Swallow As swallowing is triggered off by contraction of the mandibular elevators (masseter muscle), the teeth occlude momentarily during the swallowing act and the tip of the tongue is enclosed in the oral cavity. The transverse section shows that the dorsum of the tongue is less concave and approaches the palate during swallowing (according to Graber, 1972).
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Tongue -Thrust
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Tongue-thrust has an important effect on the etio pathogenesis of malocclusions Tongue-Thrust
Primary secondary
Anterior Lateral complex
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Endogenous Habitual adaptive
The thrust may take place in the anterior or lateral regions or can be complex. In the first case, the dysfunction is significant during the development of an anterior open bite and in the second case during the development of a lateral open bite or a deep overbite. In case of a complex tongue-thrust, the occlusion is supported only in the molar region. Cases with an anterior open bite during childhood are often self-compensating. Complex or skeletal open bites do not regulate themselves spontaneously, but rather persist.
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Primary – Secondary Dysfunctions Etiologic point of view, tongue-thrust considered primary or secondary.
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may
be
Principally speaking, all dysfunctions can be divided into primary, i.e. causal or secondary, i.e. adaptive malfunctions Causes of dysfunction
Primary
secondary
•Endogenous factors
•Adaptive
•Heredity •Limitation
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Primary tongue dysfunction in conjunction 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 sensations and to keep the oral airway open the mandible is dropped and the tongue postures forward (according to Moyers).
Hyperplastic tonsils Moderately swollen palatine tonsils which protrude significantly from the tonsillar sinus. www.indiandentalacademy.com
Adaptive tongue dysfunction Adaptive tongue dysfunction with tooth malposition. After loss of teeth, the tongue is used to fill the gaps, thus sealing the oral cavity, i.e. compensatory dysfunction. In cases with premature extraction of deciduous teeth, this primarily physiologic displacement of the tongue may persist as a functional abnormality even after the permanent teeth have erupted.
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Open Bite Due To Rickets Enamel hypoplasia of the upper and lower anterior teeth as well as of the first molars results from a vitamin D deficiency which occurred at the age of about 1 year. The skeletal and dentoalveolar open bite is aggravated by the adaptive tongue dysfunction.
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Mouth Breathing Chornically disturbed nasal respiration represents a dysfunction of the orofacial musculature; it can restrict development if the dentition and hinders the orthodontic treatment. The extraoral appearance of these patients is often conspicuous. And is termed “adenoid facies�
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Adenoid Facies
Chronically restricted nasal respiratory function.
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Occlusal and dental findings in case of oronasal respiration The upper jaw is markedly constricted, the mandibular arch is well formed. Width a bilateral cross-bite
The high palate and narrow upper arch
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The Association Between Anterior Openbite And Amelogenesis 1. Amelogenesis imperfecta were investigated clinically,
2.
and with cephalometric radiography in order to determine the prevalence and nature of the anterior open-bite It is suggested that the frequent association of anterior open-bite and amelogenesis imperfecta is caused by a genetically determined anomaly of craniofacial development, rather than by local factors influencing alveolar growth.
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4. This
anomaly characterized by infraocclusion or anterior open-bite.
an
anterior
5. “He and Issel believe that the co-existence of the two conditions may be attributed to a pleiotropic action of the amelogenesis imperfecta genes, influencing the growth of the craniofacial skeleton.
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7. Witkop and his co-workers, postulated that rough and sensitive teeth lead to abnormal tongue activity which, displaces the anterior teeth to produce a open-bite,
8. Locally interfere with the growth of the alveolar processes, and could alter the morphology of the craniofacial complex
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BIO - MECHANICAL CONSIDERATION IN OPEN BITE
Presentedby Dr.Rajashekar www.indiandentalacademy.com
CONTENTS Introduction. Definition. Types Of Vertical Malocclusion. Overview Of Open Bite. Etiologic Consideration. Esthetic Consideration. Functional Consideration Clinical Consideration Cephalometric Critera www.indiandentalacademy.com
Examination of Oro-Facial Dysfunction –Swallowing –Tongue-thrust –Cheek Dysfunction –Mouth Breathing Equilibrium Theory Influence Of Naso-respiratory Function Long Face Syndrome
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Treatment In Primary Dentition Treatment In Mixed Dentition Treatment In Permanent Dentition Conclusion.
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TREATMENT IN THE DECIDUOUS DENTITION
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TREATMENT IN THE DECIDUOUS DENTITION
1. Control of abnormal habits and elimination of 2. 3.
dysfunction should be given top priority in the deciduous dentition. The anterior open bite improves as soon as the habit is stopped. Autonomous improvement can be expected only if the deforming muscle activity is terminated and the open bite is not complicated by crowding or cross bite of the upper arch.
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4. Treatment with screening appliances is indicated in such open- bite cases.
5. A
skeletal open bite is seldom observed in the deciduous dentition. Habit control is of only secondary consideration in these cases, retarding the increasing severity of the dysplasia.
6. Extra oral orthopedic appliances such as chin caps can be used effectively to redirect growth.
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Screening Appliance 1. Screening appliances intercept and eliminate all abnormal perioral muscle function in acquired malocclusions resulting from abnormal habits, mouth breathing, and nasal blockage.
2. Open bite created by finger sucking and retained visceral deglutition-pattern, tongue function can be helped with vestibular screens.
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Mixed Dentition-treatment
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Tongue Crib 1. A removal or fixed appliance can inhibit tongue thrust. 2. The crib used with a removable appliance for an anterior open bite consists of a palatal plate with a horseshoe-shaped wire crib.
3. The crib is placed in the
area of local tongue dysfunction and resultant malocclusion.
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5. The acrylic also can be interposed between the teeth,
covering the occlusal surfaces of the upper molars, to prevent eruption of these teeth and enhance anchorage of the plate. This is especially beneficial in open-bite problems.
6. The bite-blocking here can be 3 to 4 mm, which is usually beyond the postural vertical dimension in openbite patients.
7.
In such cases a stretch reflex is elicited from the closing muscles that enhances the depressing action on the buccal segments and helps close the anterior open bite.
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Activator 1. The bite is opened 4 to 5 mm to develop a sufficient elastic depressing force and load the molar that are in premature contact.
2. Properly constructed activators that follow this principle can influence the vertical growth pattern in these cases.
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4. To “close the V� between upper and lower maxillary bases, depressing the posterior maxillary segments with the activator in a manner analogous to that of orthognathic surgery
5. In surgical open-bite cases the posterior segments are impacted, allowing autorotation of the mandible.
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Bionator 1. Used to inhibit abnormal posture and function 0f the tongue.
2. The construction bite is as low as possible, but a slight opening allows the interposition of posterior acrylic bite blocks for the posterior teeth, to prevent their extrusion.
3. To inhibit tongue movements, the acrylic portion of the lower lingual part extends into the upper incisor region as a lingual shield. Closing the anterior space without touching the upper teeth.
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4. The palatal bar has the same configuration as the standard bionator, with the goal of moving the tongue into a more posterior or caudal position.
5. The labial bow differs from the standard appliance, that the wire runs approximately between the incisal edges of the upper and lower incisors.
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6. The labial part of the bow is placed at the height of correct lip closure thus stimulating, the lips to achieve a competent seal and relationship.
7. The vertical strain on the lips tends to encourage the extrusive movement of the incisors, after eliminating the adverse tongue pressures.
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FR IV 1. Normally, anterior open bite problems show protracted tongue posture with incompetence of lips. The tongue tooth contact replaces the lip seal during deglutition to create negative atmospheric pressure.
2. FR IV along with lip exercises cause lip contact, reducing tongue protrusion and cause the tongue to move back into its normally raised position in proximity with palate, during deglutition.
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3. The palatal bow is like that of the FR-3 and is always placed behind the last molar to permit the appliance to shift in a posterior direction.
4. This allows the mandible to close up and forward into a more favorable growth mandibular plane angle.
direction
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reducing
the
Lloyd E Pearson DESCRIBES SEVEN DIFFERENT PROCEDURES FOR TREATMENT OF OPEN BITEWITH BACKWARD ROTATING MANDIBLE
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Procedure -- I 1. In the mixed dentition open-bite patient we could intrude the upper first permanent molars and then remove the remaining deciduous teeth, permitting open-bite closure.
2. occipital headgear with a transpalatal arch to control the inclination of the molars as they are intruded.
3. After the molars have been intruded perhaps 3 mm the deciduous teeth are removed, the mandible is hinged closed, and the anterior open-bite is closed. www.indiandentalacademy.com
4. The lower molars will often tend to extrude in this type of situation. Unless mechanics are designed to control their eruption.
5. An addition of a vertical pull-chin cup to the occipital headgear and transpalatal arch would intrude the upper molars, while preventing the eruption of the lower molars.
6. As the open bite closes the mandible hinges upward, reducing the height of the lower face.
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Vertical pull chin cup
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Procedure -- II 1. Extraction of first premolars and use a vertical pull-chin cup with (16 ounces of forces)
2. This can close the mandibular plane angle, reduce the lower facial height and close anterior open bites.
3. Approximately 40 of closure of the mandibular plane angle was found in his study.
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4. Four possible mechanisms of (action at work) a) maxillary sutures are pressure sensitive and some intrusion of the maxilla could occur. b) The posterior teeth tend to move forward mesially. c) A slight change in the shape of the condylar neck, with many tending to be curved more forward than previously. d) A retardation of eruption of the posterior teeth.
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Procedure -- III 1. Mandibular bite- block therapy, augmented with vertical pull-chin cup therapy, can produce a favorable holding of the vertical height throughout the growth period, intrusion of posterior teeth
2. The
hinging of the mandibular plane in a counterclockwise direction and closure of anterior open bites.
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Procedure -- IV 1. Magnetic bite blocks. 2. Although we get rapid results, two difficulties arise with bite blocks a. Extreme mouth opening and patience to tolerate the appliance. b. lateral movement of the mandible, that can cause some temporomandibualr joint strain.
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Procedure -- V 1. Intrusive forces with fully banded appliances can be developed in a number of ways.
2.
Occipital headgear has proved useful and generally seems effective in controlling the vertical dimension in the maxilla.
3. Mandibular control appears to be more difficult to manage.
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3. The lower molar normally increases its height as measured to the mandibular plane by about 1.5 mm over a two- year period
4. To reduce extrusion of the mandibular arch include a lower cervical headgear with a very light force through the center of resistance
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Procedure -- VI 1. Another useful treatment modality is vertical reduction genioplasty.
2. One advantage, is that it does not involve the temporomandibualr joints,
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3. It can be done after non-surgical treatment as an adjunct to bring the chin up and forward, to improve facial balance, and to achieve competency
4. A vertical reduction genioplasty might be more useful in patients with the correct amount of exposed gingiva in the maxilla because it does not provide maxillary anterior intrusion.
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Procedure -- VII 1. Maxillary impaction + vertical reduction genioplasty, should also be considered.
2.
This can be a great benefit to patients with i. elongated upper posterior teeth, ii. elongated upper anterior teeth, iii. a gummy simile, iv. a tall lower face, v. anterior maxilla with a maxillary impaction.
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Bracket Position 1. The placement point for incisor brackets may vary in cases of infraocclusion.
2. In cases of open bite, placing anterior brackets I mm more towards the gingival side. Inverse Anchorage Technique
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Modifications To Standard Sequence 1. The only two changes from the standard sequence are in bracket placement and the closing loop gable bend.
2. On those teeth in occlusion, the brackets are placed as close to the occlusal surface as possible.
3. On all the teeth out of occlusion, the brackets are placed more gingivally.
R.G. “Wick� Alexander www.indiandentalacademy.com
Triangle Elastics 1. Triangle elastics aid in the improvement of class I cuspid intercuspation and increasing the overbite relationship anteriorly by closing open bites in the range of 0.5 to 1.5 mm.
2. They extend from the upper cuspid to the lower cuspid and first bicuspid teeth.
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Anterior Vertical Elastics  Class II orientation.
 Class III orientation
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Avoid Intermaxillary Elastics 1. Intermaxillary elastics from the posterior teeth have a vertical force vector which extrudes these teeth and can further open the posterior vertical dimension.
2. Class II elastics from 6 - 6 should not be utilized until these teeth are well anchored in buccal cortical bone .
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How To Use Class II Or Class III Elastics 1. If class II or III elastics are required, they should be attached posteriorly to premolars rather than molars.
2. These ‘short elastics minimize the extrusive effect on the back of the arch
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ACTIVE VERTICAL CORRECTOR 1. AVC is a simple removable or fixed orthodontic appliance that intrudes the posterior teeth of both the maxilla and mandible by reciprocal forces.
2. By effective intrusion of posterior teeth, the mandible is allowed to rotate in upward and forward directions.
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3. The uniqueness of this appliance is that, it corrects anterior open bite problems by actually reducing anterior facial height.
4.
Problems formerly thought to require orthognathic surgery, can now be treated successfully with AVC.
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Method of Action :-
1. Force system -- generated by repelling magnets, 2. AVC is considered superior to a static bite block appliance energized only by the intermittent force from the muscles of mastication.
3. The constant force system of the AVC results in greater rapidity of tooth movement.
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Tooth Positioner 1. In open-bite cases, a tooth positioner may be used for 6 to 8 weeks of night-time wear
2. This appliances places elastic forces to the teeth and brings them into a predetermined ideal position.
3. It helps to keeps the open bite closed as the teeth are pulled in a vertical direction.
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Bonded fixed and Hawley retainers are also given to these patients for long-term retention. Make sure, that the mandibular anterior teeth do not contact the acrylic of the maxillary, because this would open the bite in the posterior and promote tooth extrusion, which would open the bite further
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Low transpalatal arch 1. It is considered that the transpalatal bar interferes with the normal vertical descent of the upper molars, and therefore retards maxillary vertical alveolar development.
2. It has also been stated that maxillary vertical alveolar growth contributes one third of the total vertical development of the face
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3. It is believed that, tongue pressure against the transpalatal arch during swallowing, especially when the transpalatal arch is placed low in the palate, will inhibit maxillary alveolar vertical growth.
4.
Wise et al. assessed pre and post treatment cephalometric radiographs in the study. –
They found that the transpalatal bar has no statistically significant effect on the amount of vertical eruption of the maxillary teeth.
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5. However several authors suggested that future studies with an integrated acrylic button on a lowered transpalatal arch should be conducted.
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Low Mandibular Lip Bumper 1. Cetlin and Hoeve advocated the use of a lip bumper for the development of the lower dental arch.
2. They suggested that if the lip bumper were adjusted low, the cheek and lip mucosa would rest above the appliance, and this will inhibit vertical mandibular molar dentoalveolar development.
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3. But there is no further explanation or evidence that a lower lip bumper can be used to prevent eruption of the mandibular molar teeth.
4. Similarly, a lower lingual arch may be used for controlling vertical molar development; but there is lack of evidence
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Wedge Principle Coupled With The Extraction Of Teeth Two major approaches of applying the wedge principle by extraction of teeth to control the vertical dimensions. 1. Loss of posterior anchorage so that the anchor teeth move mesially and are located farther anteriorly in the arch in an area of greater vertical dimension. 2. Extraction of first or second molars in both arches to decrease the posterior dentoalveolar height. www.indiandentalacademy.com
Garlington and Logan found that enucleation of mandibular second premolars is beneficial,
To control the vertical dimension. Increased in forward rotation of the mandible. Significant decrease in lower anterior face height.
The criteria selection :a. b. c. d.
Minimal lower arch discrepancy (6 to 10mm). A mandibular plane angle greater than 380. A hyperdivergent skeletal pattern. Increased lower anterior facial height. www.indiandentalacademy.com
 Pearson stated that after the extraction of premolar teeth, there is some mesial drift of the posterior teeth (out of the wedge) and this permits the mandible to hinge closed.
 Yamaguchi and Nanda concluded that the changes in horizontal and vertical position of the molars were dependent on the type of force application and not on the extraction or non-extraction strategy.
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The Extrusion Arch
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1. The extrusion arch is a term coined to describe the reverse action of already existing and well established intrusion arch.
2. Anterior open bite can be addressed with arch wire mechanics using asymmetrical V bends in the wire.
3. Wire used is  
16 x 22 SS or 17 X25 TMA with 900 offset bend at the molar. Extrusive force of 100 gms for 4 incisors. www.indiandentalacademy.com
Mode Of Action AT THE MOLAR:-
1. A second order couple is generated at the molar with crown tipping mesially and root tipping distally.
2. The equilibrium is achieved because the anterior end of
the wire extrudes the incisors and posterior end intrudes the molars.
3. Relatively very minimal buccal flaring of the molar is seen.
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AT THE INCISORS:-
1. Extrusion can involve single teeth or group of teeth. 2. When a group of teeth are to be extruded ,a segment of heavy arch wire may be used in the brackets of the anterior teeth, and the teeth are extruded as if they were one big tooth.
3. Whether the extrusion arch is tied segmentally or to continuous arch wire or placed directly into the brackets the effect is the same www.indiandentalacademy.com
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High Pull Headgear
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Multiloop Edgewise Arch Wire 1. Multiloop Edgewise Arch Wire was developed by Kim to achieve these goals :a. Correcting the inclination of the occlusal planes. b. Aligning the maxillary incisors relative to the lip line. c. Uprighting the axial inclinations of the posterior teeth.
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1. The
MEAW contains horizontal and vertical loops fabricated from a 16 x 22 ss wire in an L - shape fashion
2. The vertical loops act as a break between the teeth, lowers the load deflection rate and provides horizontal control.
3. The horizontal loops further reduces the load deflection rate and provides vertical control.
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4. Typical tip back bends of 3-5degrees are given on each tooth.
5. Elastics are placed between the loops that lie mesial to opposing cuspids.
6. Recommended elastic size is 3/16 inch heavy, with a force approximately 50 gms when the jaw is closed.
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ď ś KIMS technique was later modified by AYHAN ENACAR et.al, using 16 x 22 reverse curve NiTi arch wires with heavy intermaxillary elastics applied in the canine region
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High Angle Begg Cases 1. In high angle begg cases we avoid class II elastics to avoid open bite and accentuation of present class II .
2. We give mild class I elastics in such cases.
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Skeletal Anchorage System 1. Skeletal anchorage system was developed for tooth 2. 3.
movements. SAS consists of titanium miniplates, that are temporarily implanted in the maxilla or the mandible as an immobile anchorage. These miniplates are fixed at the buccal cortical bone around the apical regions of the lower first and second molars on both the sides.
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4. Elastic threads are used as a source of orthodontic force to reduce excessive molar height.
5. The lower molars were intruded about 3 to 5 mm, and open-bite was significantly improved with little if any extrusion of the lower incisors, with counter clockwise rotation of the occlusal plane .
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ďƒ˜
SAS is an effective adjunctive biomechanical procedure for correction of skeletal open-bite malocclusion with out unfavorable side-effect.
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Care Regarding use of appropriate force system
1. Light forces and preparation of anchorage may prevent extrusion of the posterior teeth.
2. The segmented arch technique to be superior in preventing posterior dental extrusion during incisor intrusion
3. It is preferable to include second molars in the posterior segments to distribute the forces of occlusion over a larger area, thereby counteracting the extrusive forces on the buccal segments www.indiandentalacademy.com
Conclusion Indeed it is a daunting and challenging job to treat open bite cases by now you will agree on that point I think.
“A thing started nicely is half work done” so taking this guideline and putting meticulous attention to biomechanics, I think we can very successfully treat the very difficult open bite cases .
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