Rest of lost vert dim/ academy general dentistry

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  • Stomatognathic system is a remarkable example of multiple bioengineering/ an assemblage that’s connected or interdependent so as to form a complex unity, therefore no system works well if its parts are not in their proper place. Masticatory system is no exception
  • There is a definite inter-dependency between the motors/muscles, the contacts/ teeth and the hinges/TMJ. Any alteration of one can affect the other
    The concept of vertical dimension of occlusion is based on the contracted length of elevator muscles which means to say that the teeth are not the determinants of VDO but rather their position is determined by the vertical space available bw the fixed maxilla & muscle positioned mandible
  • Although a static relationship in principle, the vertical dimension of facial skeleton is initially determined by the interaction of the genetic growth potential of the craniofacial tissues, environmental factors, and the dynamics of neuromuscular function during growth. Maintenance of the vertical dimension of occlusion is principally related to the interaction of environmental factors and the dynamics of neuromuscular function throughout the aging process.
  • Throughout life, there is an eruptive force that causes teeth to move vertically with their alveolar bone until they meet resistance that is equal to their eruptive force
    Usually the stopping force is contact with teeth in the opposing arch
    Eruption may be stopped by equal resistance from the tongue, thumb, lips or any object that’s held bw the teeth including a pipe/appliances that cover the occlusal surface
    Berry &Poole sugested occlusal tooth surface loss is compensated by alveolar growth which maintains the occlusal vertical dimension. However, if the rate loss is greater than the compensatory mechanism then the OVD is reduced.
  • Environmental factors play a particular role in the development of the vertical dimension of the facial skeleton and ultimately the vertical dimension of occlusion
    Function of the upper respiratory system has been shown in a number of studies to play a particular role in this regard
    Linder-Aronson21 suggests that, for certain subjects, mandibular retrognathism, increased vertical facial height, open bite, and crossbite may be due to chronic environmental factors such as airway obstruction, and that treatment should be directed at eliminating or reducing the environmental effects on jaw position and dental occlusion.
  • Once growth is complete, maintenance of the vertical dimension of occlusion is determined by the adaptive capacity of the biologic system to insult or injury.
    Adaptive responses can occur within the temporomandibular joint (TMJ), the periodontium, and the dental occlusion.
    In most cases, it is the soft tissues of the TMJ and periodontal ligament that initially respond to acute micro- and macrotrauma.
    The first response within the TMJ to compressive forces is a shift in the fluids within the disc and retrodiscal tissues.
    Once the strain is relieved, the fluid will return to its original position and the morphology of the tissues is maintained.
    However, prolonged strain with these tissues will result in an alteration of the architecture of the collagen and noncollagen proteins and ultimately a change in tissue morphology.
  • Stress beyond the levels of adaptation for the soft tissues will then result in morphologic adaptive changes within the cartilage and bone that may be apparent radiographically.
    Stress beyond the adaptive capacity of the tissues will result in degeneration, a loss in vertical support, and structural changes that have the potential to impact the vertical dimension of occlusion
  •     Occlusal wear is most often attributed to attrition, which is defined as the wearing away of one tooth surface by another tooth surface. This gradual wear of teeth is thought to be a normal process during the lifetime of a patient.
    However, excessive occlusal wear can result in pulpal pathology, impaired function, occlusal disharmony, and esthetic disfigurement.
    Intracapsular disorder: decreased ramus ht. puts the molars into interference
    Posterior tooth : Interference with completely seated TMJ / anterior guidance
    All the worn surfaces can be contacted during centric relation closure / during excursions to and from CR
  •     Abrasion of teeth : Abrasion of teeth is the wearing away of tooth tissue by external agents. Occlusal abrasion is usually attributed to diet and chewing of abrasives such as tobacco. Environmental factors, such as constant exposure to dust and grit in a farming occupation may cause abrasion of teeth. Unglazed porcelain restorations cause abrasion of opposing natural teeth.
    Erosion : Erosion is the destruction of hard dental tissues by chemical action. Tooth erosion may be caused by citrus juices, cola drinks, vinegar, and pickled foods.. Patients who continuously regurgitate stomach contents into the mouth, commonly exhibit erosion on the lingual surfaces of maxillary anterior teeth.
    Loss of posterior support : Extensive attrition of anterior teeth often occurs when posterior support has been compromised by loss of teeth, malposition of teeth, or occlusal interference that drives the mandible forward and exerts undue force on the anterior teeth. It should be emphasized that most often a combination of factors is responsible for the wear.
  •     Congenital anomalies : Among the congenital anomalies, amelogenesis imperfecta, and dentinogenesis imperfecta are important conditions that may cause accelerated wear of teeth because of softness of enamel or dentin.[3] Amelogenesis imperfecta is of three types: hypoplastic, hypomaturation, and hypocalcified.[4] In the hypoplastic type, the enamel has one-eighth to one-fourth of the normal thickness. The enamel thickness in hypomaturation and hypocalcified type is normal. However, the enamel in hypomaturation type is softer, whereas the enamel in hypocalcified type is very friable.[2]Dentinogenesis imperfecta or hereditary opalescent dentin is a dominant autosomal trait with a high degree of penetrance.[2] The dentin is amber colored and translucent. The attachment with the normal enamel is weaker and results in separation of enamel from dentin.[2] Thus, the softer dentin is exposed to oral environment and subjected to rapid attrition.
  •     Bruxism and other parafunctional habits : Both diurnal and nocturnal bruxism have been found to be related to extensive tooth wear. Bruxism may be triggered by occlusal interferences. Occlusal splint therapy and occlusal adjustment may be needed to control bruxismOther habits include chewing tobacco, pipe smoking, pencil or pen biting, and holding objects between the teeth. These habits are usually associated with emotional stress. Patient counseling and periodic self-monitoring may help to break away from these destructive habits.
  • Loss of VDO has its effects on the appearance of the individual, the masticatory efficiency, neuromuscular system, tmj, and the dental occlusion
    Functional surfaces of teeth become flatter and wider, disrupting the occlusal plane
    As mandible is elevated, mus have to contract more until lower teeth touch the upper teeth leading to over closure and deep bite
    Lack of stable holding contacts on anterior teeth causes the lower incisal edge to wear at sharp angle causing distalising effect on the condyles
    Overcontraction of muscles requires more energy demands and ultimately the muscle is stressed and fatigued
    Other changes include thinning of lips, forward positioning of mandible causing chin prominence and chin closer to nose
    Exaggeration of facial folds
  • Pindborg's original classification of TSL
    Compensated TSL: Tooth surface loss without loss of OVD. It generally involves a complete or nearly complete dentition and the free-way space remains within the normal range.
    Non-compensated TSL: Tooth surface loss leading to the loss of OVD. This is often confined to the anterior segments and associated with a lack of posterior occlusion. The rate of wear, confined to a smaller number of teeth, results in an apparent lack of compensatory eruption and the free-way space is greater than normal.
  • It is critical to verify loss of occlusal vertical dimension (OVD) before the restoration of lost OVD. Evaluation of VDO: The different techniques that can be used are: phonetics, assessment of interocclusal distance, or the evaluation of soft tissue contoursPhonetic evaluation: Both Pound and Silverman have described the reliability of the speaking space as a method to determine OVD for complete denture patients. The normal mandibular position during the 's' sound places the incisal edge of the mandibular incisors about 1 mm inferior and lingual to the incisal edge of the maxillary incisors. Vertical positioning significantly more than 1 mm apart may indicate lost OVD. This may not be true in patients with Angle's classes II and IIIInterocclusal distance Methods of measuring interocclusal distance are diverse, inaccurate, and inconsistent. Measurements can be used as supplemental diagnostic aids /be used as mere guidelines. A good clinical judgment must prevail. A patient who demonstrates an interocclusal distance of 6 mm is more capable of tolerating a slight increase in OVD than the patient with an interocclusal distance of 2 mm.
    Facial Measurement: Vertical distance from the external corner of the eye (outer canthus) or the pupil to the corner of the mouth
    Vertical distance from the eyebrow to the ala of the nose
    Vertical length of the nose at the midline (from subnasion to glabella)
    None of the above techniques are found to be scientifically as accurate as their proponents claim. Use of more than one technique of evaluation of OVD may increase the accuracy and reliability.
  • The orderly sequence for occlusion based treatment planning involves
    First evaluation of CR position of the mandible
    Second step is Evaluation of VDO. The joints, muscles, and teeth must be placed at an acceptable VDO in the final restorations
    Finally restoration with equilibrated occlusal scheme in an appropriate occlusal plane
  • When changes of VD are anticipated as part of the restorative trmt, there are 7 stages to be considered during trmt plan
    Assessment
    Diagnostic appliance
    Diagnostic wax up
    provisional restorations
    Clinical assessment of response
    Mount casts of provisional restorations
    Mount working casts at the correct VD for final restorations
  • If assessment indicates a decrease in VD, an acrylic overlay appliance is fabricated- either to the anticipated VD or if this appears excessive, to an intermediate dimension with additions being made periodically until the planned VD is reached or until the pt experiences discomfort.
    The tolerance of the clinical procedures by the patient should not be exceeded
    There are no reliable diagnostic tests to establish how much, if any VD needs to be re-established. The amount of Interocclusal clearance is a crude guide, since the muscle tone which determines the clearance is variable
    The best test may be the trial and error followed by the construction of the stabilization splint which the pt wears for around 3 months where in the muscles particularly the elevator muscles would adapt to the new VD
  • Bite raising appliances increase the jaw-to-jaw dimension & interfere with the repetitive contracted length of the elevator muscle.
    This occurs by intrusion of the covered teeth by an amount approximately equal to the thickness of the bite plane
    When the posterior bite-raising appliance is removed, the teeth is covered will be out of contact . Intrusion of teeth occurs within 6-12 months
    So the restorative stage would utilize the space when the intrusion has occurred and sufficient bite opening has ocurred
    Eruption of teeth can be stopped by habitual tongue biting. VDO at complete closure includes the thickness of the tongue. Such dentitions can be just as stable as if the teeth were in contact at complete closure
  • According to the treatment protocol, different types of splints are used to raise the bite and thereby stabilize it. This includes
    Anterior splint: provided anterior tooth contact only on a flat surface perpendicular to the long axis of the mandibular incisor teeth
    Stabilization splint : has a uniform occlusal contact of the anterior and posterior teeth
    Anterior repositioning splint : holds the condyles slightly (0.5 – 1 mm anterior and inferior to the intercuspal position and had uniform occlusal contact of all teeth
    Bilateral pivot splint: had pivots placed bilaterally between the second molars and had no other occlusal contacts
    Unilateral pivot splint: had a pivot placed between the second molar one side of the dental arch
  • There are four philosophies for condylar position when determining VD. All work on the basis of a canine protected occlusion
    1. Gnathological
    Involves use of fully adjustable articulators to determine condylar path from the hinge axis and setting this path for a 5 degree increase to ensure no posterior interference
    2. Bioaesthetics
    Works via a fixed numerical value based on incisal relationship. Distance between gingival margins of 18-20 mm in an unworn class one occlusion, with upper incisal length of 12 mm, lower incisal length 10 mm, 4 mm overbite and 1 mm overjet.
    3. Centric relation based
    Following the principles of P. Dawson whereby CR is defined as ‘when the heads of the condyles are in their most superior position within their sockets, lateral pterygoid muscle is relaxed and the elevator muscles are contracted with the disc properly aligned’.
    4. Neuromuscular
     
    Based on the principles of muscle activity determined by electromyography.
  • 3. Centric relation based : Following the principles of P. Dawson whereby CR is defined prior to change in VD
    4. Neuromuscular: Based on the principles of muscle activity determined by electromyography.
  • In Dawson’s technique, prior to VD corrections, mandible has to be established in CR . The importance of CR as told by Dawson is that during CR
    The disk is properly aligned on both condyles
    The condyle-diskassemblies are at the hightest point possible against the posterior slopes of the eminentiae
    The medial pole of each condyle-disk asssembly is braced by bone
    The Superior lateral pterygoid muscle have released contraction and are passive
    The TMJs can accept firm compressuve loading with no sign of tenderness or tension
  • Once the VD has been established by means of the diagnostic appliance, it must be transferred to the articulator for diagnostic waxup and provisional prosthesis
    With the dianostic appliance in place, measure the VD of intercuspal position by recording the distance bw 2 suitable gingival land marks with calipers. Transfer this to the mounted diagnostic casts and set the incisal pin.
    Reshaping of teeth for both favorable esthetics & incisal guidance should be planned by waxing the desired contours at the present VD
    Provisionals are fabricated
  • Provisionals made from the diagnostic waxup placed anteriorly & anterior section of the maxillary splint cut away with the posterior part adjusted to give contacts against lower teeth
    Composite resin: with the ant provisionals in place, any available enamel on the posterior teeth is etched and composite resin placed & adjusted to provide occlusal contacts
    Placing provisionals on posterior first with the maxillary splint modified to maintain the anterior contacts
    Provisionals placed both anteriorly and posteriorly.
  • Successful treatment of most wear related problems requires the separation of all posterior teeth in all jaw positions except centric relation, the analysis of any severe wear problem must focus on how the posterior disclusion can be achieved.
    Disclusion depends on a combination of anterior guidance & condylar guidance
  • The position, inclination & lingual contour of the upper anterior teeth combine to establish the anterior guidance.
    When only the ant gui is worn flat with apparently normal posterior occlusion and normal condylar guidance, downward path of condyles must be relied on for posterior tooth disclusion in excursions
    Commonly achieved raising the posterior bite using restorations with optimum cusp height & angulation
  • Clinically evident by the wear pattern of upper lingual cusps / flattening of upper lingual cusps cannot occur with normal condylar path
    A steepened anterior guidance may be the only option for posterior disclusion if the condylar path has been flattened
  • The exception to the above rules may occur when there is a severe curve to occlusal plane & the plane slants up in back, making it nearly parallel with an undamaged condylar path
    When the occlusal plane at the molars parallels the condylar path, the posterior teeth may be worn flat and the problem can be corrected by lowering the occlusal plane
  • In a typical category-1 patient (loss of VDO), the closest speaking space is more than 1 mm and the interocclusal space is more than 4 mm & has some loss of facial contour that includes drooping of the corners of the mouth
    The reliable method to confirm the diagnosis and to determine a physiologic VDO is placement of trial restorations.
    First, a removable splint or partial denture is placed and observed periodically for 6-8 weeks.
    A removable trial restoration cannot be solely relied because the patient may have removed the prosthesis during periods of stress, fatigue, and soreness associated with excessive OVD.
    Fixed provisional restorations are placed for another 2-3 months before planning permanent restorations.
    In patients of category-1, all teeth of one arch must be prepared in a single sitting once the final decision is made. This makes the increase in VDO less abrupt and allows better control of esthetics.
  • Patients in category-2 typically have a long history of gradual wear caused by bruxism, moderate oral habits, or environmental factors
    In these patients, the OVD is maintained by continuous eruption
    Tooth preparation to establish retention and resistance form may be critical because of shorter crown length
    Gingivoplasty may be needed to gain clinical crown length
    Enameloplasty of opposing posterior teeth may provide some space for the restorative material
  • In patients of category-3, there is excessive wear of anterior teeth, which has occurred over a long period, and there is minimal wear of the posterior teeth
    Centric relation and centric occlusion are coincidental with a closest speaking space of 1 mm and an interocclusal distance of 2-3 mm
    In such cases vertical space must be obtained for restorative materials.
    This can be accomplished by orthodontic movement
    Restorative repositioning
    Surgical repositioning of segments, if a dentofacial deformity exists in conjunction with extreme wear
  • POSSIBLE CLINICAL CONCERNS BEHIND CHANGING VD
    Joint or muscle pain
    This is not a problem, as altering VD does not produce pain of more than one to two weeks’
    duration; any pain is a result of increased temporary muscle awareness.8
    Stability
    Relapse of restored VD variable without any fixed parameters
    Muscle activity
    VD increases electromyographic activity of the elevator muscles when clenching. This is short lived as if readings are taken two to three months later they will have returned to base line values. The postural muscle tone (ie the rest position) reduces when VD is increased but is also back to normal within three months. 10
    Phonetics: wait for one month to see if the patient can adapt before considering any changes. Most often depends on the lower incisor position
    Increased VD shortens the lower incisors in relation to the upper incisors threfore ht. has to restored
    Also improved by restoring the palatal surface of the upper incisors
  • It’s the first criterion for success because complete fulfillment of all the other criteria ia dependent on satisfying this first criterion
    If the tmjs cant accept firm loading, it indicates that either the condyles are braced by the lateral pterygoid muscles or ther is an intracapsular disorder that has a probability of instability of the tmj
    Trmt that does not end up with complete comfort of the tmj during maximal loading by the elevator muscles cannot be considred a completely successful trmt
  • One of the simplest yet most effective tests for determining if occlusal interference is a factor in orofacial pain
    pt is asked to close and squeeze the teeth together/ empty mouth clench.
    perfected occlusion shall not show any sign of discomfort in any tooth or in the joint regardless of how hard the pt bites
    Discomfort in a tooth is certain sign of premature or deflective contact
    If the clench test also produces discomfort in the masticatory musculature, it’s a positive indication for an occluso-muscle disorder
  • Determines if there are posterior interferences.
    If the pt feels contact on any posterior tooth while grinding the teeth through any / all excursions, it’s a positive indication that posterior disclusion has not been achieved
    Posterior interferences, hyperactivates muscles while posterior disclusion shuts off all the elevaytor muscles except the anterior temporal motor units
  • Light contact on the labial surfaces of each upper anterior tooth using the edge of fingernail, when the patient taps the teeth together lightly they firmly
    Any movement of any ant teeth is an indication that the tooth is in interference
    This interference can occur from a restrictive envelope of function/ failure to provide a needed long centric
    Commonest cause: deflective posterior incline that forces the man forward into hard contact with the anterior teeth
  • Refers to stable TMJ and stable dentition: if both jonts and the teeth are stable, there shd be no need for readjustment of the occlusion for a perior of at least 3 months. Once instability , then the trmt goal becomes one that of “manageable stablity”
    Conditions that may not satisfy stability include osteoarthritic breakdown of condyle/ eminence, excessive wear of teeth, Hypermobility, shifting of tooth position
  • The pt shd have complete comfort of the teeth, the lips and the face
    Speech shd be comfortable and not cause tiredness in facial and masticatory muscles
    A perfected occlusion results in a peaceful neuromuscular system & that’s the goal of all occlusal therapy
  • The pt shd be happy with the appearance of the smile
    It’s a consistent finding that the functional harmony is dependent on anatomic harmony
    Comfort test shd include comfortable, unstrained speech, with correctly placed incisal edges in harmony with the neutral zone
  • This was a 45 year old man with a habit of bruxing in the day as well as while sleeping.
    The attrition was marginally less in the posteriors as compared to the anterior teeth
    There was a total collapse of the vertical dimension
    The lower anterior teeth were totally razed to the gingival level
    The upper lateral incisors and canines were also very badly destroyed
  • The second molars were the only teeth in any form of intercuspating occlusion
    The first molars showed more than 40% attrition on the occlusal surfaces and there was no intercuspation of any sort.
    The upper right lateral incisor and canine were attrited to the gingival level.
    The lower anteriors from the right first premolar to left canine were totally razed to gingival level.
    All the remaining teeth presented with more than 40% of loss of crown structure
    The patient was unable to reproduce any stable centric occlusion.
    Lateral and protrusive excursions were not guided correctly by any group of teeth.
    There was a total loss of vertical dimension (approximately 5 mm at the central incisor level)
    The periodontal condition was very good.
    There were no signs whatsoever, of any inflammation or disease process
    There were very few incipient or advanced carious lesions seen in the existing teeth.
    The loss of tooth structure was clearly attributed to the patient's habit of bruxing.
    A total of nine teeth showed pulp exposures in spite of the secondary dentin formation.
  • Occlusion was checked in centric position
    Then checked in protrusive and lateral movements
    Patient's comfort levels were also checked and the ability of the patient to intercuspate repeatedly at the same centric position, was evaluated
  • Intraoral examination of a 31-year-old female patient with severe sensitivity and tooth wear revealed a full complement of the permanent dentition
    incisal aspects of maxillary and mandibular anteriors were completely worn away exposing the pulp chambers
    The occlusal aspects of all the posterior teeth were also severely worn
    Cervical and proximal enamel was found to be normal.
    The attrition of the molars resulted in a decrease of the vertical dimension of occlusion.
    The interocclusal distance at physiologic rest position was 7.3 mm
    Centric occlusion position was coincident with the maximum intercuspal position
    The gingival status was found to be good and well maintained
    The oral hygiene of the patient was satisfactory.
  • A panoramic radiographic examination
    The enamel of the teeth appeared to have the same radiodensity as dentin and the morphology of the roots were normal.
    The pulp chambers were normal with no evidence of calcification.
    The cementum, lamina dura, and bony trabeculations were within normal limits
  • Since the heights of the crowns of the maxillary and mandibular teeth were inadequate for the fabrication of the prosthesis, an apically positioned flap was planned as a part of the crown lengthening procedure with consideration for biologic width dimensions. The surgical site was allowed to heal for three months. Finally, increase of crown height by approximately 2 mm was achieved.
    Caries excavation was done for all carious teeth.
    Endodontic therapy was carried out as required
    Bite registration using Type II modeling wax
    Increased vertical dimension of 5 mm with 3 mm of freeway space
    Splint fabricated with heat-cured Polymethyl methacrylate acrylic resin
    Patient used the splint for three months
  • Full-mouth, heat-cured provisional restorations were fabricated at the desired vertical dimension (with 3 mm freeway space) using methyl methacrylate acrylic resin. The provisional restorations were temporarily cemented
  • After completion of endodontic therapy, the maxillary anterior teeth were prepared with post spaces for cast post cores and for prefabricated posts for the mandibular anterior teeth.
    Composite core build-ups for premolars and the right first molar in order to increase the crown height.
    Crown preparations were done for porcelain-fused-to-metal (PFM) restorations for the maxillary and mandibular anteriors, premolars, and maxillary first molars; on the remaining teeth all-metal restorations were used
  • Photograph showing anterior view of the rehabilitated dentition in occlusion, one year after treatment.
  • Most patients with severe wear of teeth can be managed by restoring the occlusion and without increasing the vertical dimension. If the VDO has to be increased, such as in Turner and Missirlian class-III situation, it has to be done cautiously. According to literature, a limited increase in vertical height can be tolerated and well adapted. The amount of vertical height to be increased is best judged by placing removable splint/denture and fixed provisional restorations. The final restoration should mimic the OVD, function, and esthetics that have been developed in the fixed provisional restoration.
  • “Bilateral relaxation of external pterygoid muscle is essential to obtain true centric”
    Manual guidance is the use of external guidance by the operator to assist the subjects musculature to seat the condyles & mandible in centric position. The limitation with manual guidance is the difficulty in relaxing the antagonist muscles, which protrude the jaw.
    Chin Point guidance – Guichet (1970): thumb & forefinger positions the condyle in RUM position
    Bimanual method – Peter Dawson (1974): guides the mandible in most superior anterior position
    Three Finger method – Peter Thomas 1980: Positions condyle in anterior superior position
    B. Anterior Deprogrammer: provides anteiror stop to eliminate posterior tooth contacts during closure of jaws, thereby eliminating proprioceptive invluence from the teeth. This allows subjects neuromusculature to seat the condyles in its centric position without the influence of pdl proprioception or engram / without manipulating it guides the mandible
    Leaf guage principle – (Long 1973), Williamson (1980): leaf guage guides the mandible to obtain optimum superior anterior braced position of the condyles against the disc. Mc Horris felt that the leaf guage helps to tripodize the mandible and brace the condyles in AS position against the poasteior slope of articular eminence. Long found that leaf guage is a reliable method for consistently placing the condyles in centric position.
    Anterior Jig – Lucia (1983) :
    Jig is a covering on the upper incisors fabricated in acrylic resin having an occlusal platform against which the lower anterior teeth will close. It acts as a third leg of tripod, the other 2 legs being the condyles. This leg acts as an anterior resistance and stops mandibular closure, without any deviation. Jig is a useful tool for obtaining centric inteocclusal records free from deflective contacts and therefore eliminates the influence of engrams during centric registration.
    Types of anterior deprogramming devices:
    The concept of anterior deprogramming was introduced by Stuart when he placed a wooden tongue blade between upper and lower teeth while closing the jaws. Hart Long gave a scientific approach to it by inventing the leaf gauge. Lucia obtained a similar effect with an anterior jig. Woelfel introduced his OSU leaf wafer technique to obtain centric inter-occlusal record.
    Leaf Gauge consists of fifty, 0.1 mm thick polyester, vinyl leaves of 10 mm x 50 mm bound together at one end to form a gauge. X number of leaves is placed between anterior teeth to obtain posterior disclussion and centric seating of the condyles. Leaf gauge eliminates the potential error in manipulating the patients jaw into centric relation by permitting patients own neuromuscular to seat the condyles correctly (Hufmann, Mc Millen).
  • Rest of lost vert dim/ academy general dentistry

    1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com
    2. 2. www.indiandentalacademy.comwww.indiandentalacademy.com
    3. 3. Introduction www.indiandentalacademy.comwww.indiandentalacademy.com
    4. 4. www.indiandentalacademy.comwww.indiandentalacademy.com
    5. 5. www.indiandentalacademy.comwww.indiandentalacademy.com
    6. 6. Definitions: GPT 8  Vertical Dimension of Occlusion : The distance between any two points measured in the maxilla and the mandible when the teeth are in maximum intercuspation  Vertical Dimension of Rest : The postural position of mandible when an individual is resting comfortably in an upright position and the associated muscles are in a state of minimal contractural activity  Interocclusal Clearance : The arrangement in which the opposing occlusal surfaces may pass one another without any contact The amount of reduction achieved during tooth preparation to provide for an adequate thickness of restorative material  Interocclusal Distance : The distance between the occluding surfaces of the maxillary and mandibular teeth when the mandible is in a specified positionwww.indiandentalacademy.comwww.indiandentalacademy.com
    7. 7. Peter E. Dawson: The repetitive contracted length of the elevator muscles determines the vertical dimension of occlusion i.e. The vertical space between the fixed maxilla and muscle positioned mandible into which the upper and lower teeth intercuspates at the most closed position What isVDO ? www.indiandentalacademy.comwww.indiandentalacademy.com
    8. 8. VERTICAL DIMENSION  Static relationship  Initially determined by interaction  Genetic Growth Potential  Environmental factors  Dynamics of Neuromuscular Function during growth  Maintenance of VD O  Interaction of environmental factors  Dynamics of neuromuscular function throughout aging process www.indiandentalacademy.comwww.indiandentalacademy.com
    9. 9. EruptiveForceVsTooth Wear  Throughout life, eruptive force causes teeth to move vertically with their alveolar bone  Stopping force:  Teeth of opp arch  Tongue..Thumb …Lips  Objects…. Pipes/ appliances  Dentoalveloar Compensation: [Berry & Poole 1976]  TSL compensated by alveolar growth which maintains occlusal vertical height eg.: Bruxism  Rate of wear > comp alveolar growth = Loss of VDO www.indiandentalacademy.comwww.indiandentalacademy.com
    10. 10. Environmental Factors  Particular role in the vertical dimension of facial skeleton, ultimately the VDO  Function of upper respiratory tract (Linder- Aronson)  Mandibular Retrognathism  Increased vertical facial height  Open bite  Cross bite……chronic airway obstruction www.indiandentalacademy.comwww.indiandentalacademy.com
    11. 11. Biologic Adaptation/Maintenance of VD  Adaptive responses can occur within  Temporomandibular joint (TMJ),  Periodontium  Dental Occlusion  First Response : within TMJ  Strain: Shift in the fluids within the disc and retrodiscal tissues  Strain is relieved: The fluid will return to its original position and the morphology of the tissues is maintained.  Prolonged strain : Alteration of the architecture of the collagen and non-collagen proteins and ultimately a change in tissue morphology www.indiandentalacademy.comwww.indiandentalacademy.com
    12. 12.  Stress beyond the levels of Adaptation : Morphologic adaptive changes within the cartilage and bone, that may be apparent radiographically  Stress beyond the adaptive capacity of the tissues :  Degeneration  Loss in vertical support  Structural changes that have the potential to impact the vertical dimension of occlusion www.indiandentalacademy.comwww.indiandentalacademy.com
    13. 13. Tooth Wear Physiological Pathological/ Excessive At a lower rate Molar: 29 µ m/ year Premolar: 15 µ m / year At a Higher rate Parafunction: 3 times of normal oLoss of convexity on the cusps oFlattening of cusp tips on posterior tooth oLoss of mammelons on anterior tooth oWear facets with minimal length & depth oUnacceptable damage to occluding surfaces oDestroy anterior tooth structure oLoss of anterior guidance oNon Diagnostic Diagnostic: Dependably related to tooth surfaces that are in direct interference with functional / para functional movements of mandible www.indiandentalacademy.comwww.indiandentalacademy.com
    14. 14. Tooth Wear  Attrition  Normal Process  Excessive occlusal wear  Pulpal pathology  Impaired function  Occlusal disharmony  Esthetic disfigurement  Intracapsular disorder  Decreased ramus ht. puts the molars into interference  Posterior tooth Wear:  Interference with completely seated TMJ / anterior guidance  Worn surfaces can be contacted during centric relation closure / during excursions to and from CR www.indiandentalacademy.comwww.indiandentalacademy.com
    15. 15. Tooth Wear  Abrasion of teeth  Diet & chewing of abrasives (tobacco)  Environmental Factors Dust & grit  Unglazed porcelain restorations  Erosion  Chemical action Citrus juices…Cola drinks… Vinegar…Pickled foods  Constant Regurgitation/ Projectile vomiting (GERD)  Loss of Posterior Support  Attrition of Ant. teeth ….  Loss of posterior teeth  Malposition of teeth  Occlusal interference…. Drives mandible forward www.indiandentalacademy.comwww.indiandentalacademy.com
    16. 16. Tooth Wear  Congenital Anomalies  Amelogenesis Imperfecta Hypoplastic … . 1/8 – ¼ enamel thickness Hypomaturation … . .softer enamel Hypocalcified … . friable enamel  Dentinogenesis Imperfecta Weak enamel attachment Rapid Attrition www.indiandentalacademy.comwww.indiandentalacademy.com
    17. 17. Tooth Wear  Bruxism /Parafunctional habits  Occlusal interferences Occlusal splints Occlusal adjustments  Chewing Tobacco  Pipe smoking  Pencil/ Pen biting  Holding objects b/w teeth  Emotional stress Patient counseling & periodic self-monitoringwww.indiandentalacademy.comwww.indiandentalacademy.com
    18. 18. Consequenceof Lossof VDO  Appearance  Masicatory efficiency  Neuromuscular system  TMJ  Dental occlusio  Functionsl surfaces of teeth: flatter and wider, disrupting the occlusal plane  Overclosure and deep bite  Distalising effect on the condyles  Overcontraction of muscles: are stressed and fatigued  Thinning of lips  Forward positioning of mandible causing chin prominence and chin closer to nose  Exaggeration of facial folds www.indiandentalacademy.comwww.indiandentalacademy.com
    19. 19. Costen Syndrome  In 1934, Costen described a symptom complex that included  Loss of dental occlusal support  Ear symptoms (such as pain and tinnitus)  Sinus pain  Agerberg has reported that the number of missing teeth was directly correlated with increasing symptoms of mandibular dysfunction www.indiandentalacademy.comwww.indiandentalacademy.com
    20. 20. Classification www.indiandentalacademy.comwww.indiandentalacademy.com
    21. 21. Clinical Classification of Tooth Wear Pindborg's original classification of TSL  Compensated TSL: Tooth surface loss without loss of OVD  Complete or nearly complete dentition  Free-way space remains within the normal range  Non-compensated TSL: Tooth surface loss leading to the loss of OVD.  Confined to the anterior segments  Associated with a lack of posterior occlusion  Rate of wear, confined to a smaller number of teeth  Lack of compensatory eruption  www.indiandentalacademy.comwww.indiandentalacademy.com
    22. 22. Clinical Classification of Tooth Wear Turner & Missirlian Category-1: Excessive wear with loss of VDO Category-2: Excessive wear without loss of VDO but with space available Category-3: Excessive wear without loss of VDO but with limited space JPD, Year : 2005  |  Volume : 5  |  Issue : 2  |  Page : 89-93 www.indiandentalacademy.comwww.indiandentalacademy.com
    23. 23. Evaluation of VDO Phonetic evaluation (Pound & Silverman)  Normal mandibular position during the 's' sound ….. incisal edge of the mand incisors about 1 mm inferior and lingual to the incisal edge of the maxillary incisors Interocclusal Distance  Supplemental diagnostic aids / guidelines.  Interocclusal distance of 6 mm : is more capable of tolerating a slight increase in OVD than the patient with an interocclusal distance of 2 mm. (Turner KA, Missirlian DM) Facial Measurements  Vertical distance from the external corner of the eye (outer canthus) or the pupil to the corner of the mouth7  Vertical distance from the eyebrow to the ala of the nose  Vertical length of the nose at the midline (from subnasion to glabella) www.indiandentalacademy.comwww.indiandentalacademy.com
    24. 24. Diagnosis& Trmt Planning Orderly Sequence for occlusion based treatment planning : I. Evaluation of CR position of the mandible II. Evaluation of VDO to be raised -- Joints, muscles, & teeth must be placed at an acceptable VDO in the final restorations III. Finally restoration with equilibrated occlusal scheme in an appropriate occlusal plane Initial Treatment: I. Extraction of hopeless tooth II. Periodontal assessment III. Caries control IV. Endodonticswww.indiandentalacademy.comwww.indiandentalacademy.com
    25. 25. VDO : Increase/ Decrease? Michael D. Wise  Assessment  Diagnostic appliance  Diagnostic wax up  Provisional restorations  Clinical assessment of response  Mount casts of provisional restorations  Mount working casts at the accepted VD for final restorations www.indiandentalacademy.comwww.indiandentalacademy.com
    26. 26. Diagnostic Appliance  Assessment : Decrease in VD  Acrylic overlay appliance is fabricated  Either to the anticipated VD or if this appears excessive, to an intermediate dimension with additions being made periodically until the planned VD is reached or until the pt experiences discomfort  Tolerance of the clinical procedures by the patient should not be exceeded I. No reliable tests II. Crude guide: inter occlusal clearance III. Best Test : Time tested Trial & Error IV. Stabilization splint : 3 months V. Adaptation of the muscles www.indiandentalacademy.comwww.indiandentalacademy.com
    27. 27. Bite- raising Appliance • Bite raising appliances increase the jaw-to-jaw dimension & interfere with the repetitive contracted length of the elevator muscle • Occurs by intrusion of teeth covered, by an amount approximately equal to the thickness of the bite plane • Restorative phase would utilize the space when the intrusion has occurred and sufficient bite opening has ocurred • Extrusion of teeth occurs within 6-12 months • Eruption of teeth can be stopped by habitual tongue biting www.indiandentalacademy.comwww.indiandentalacademy.com
    28. 28. Typesof Splints • Anterior splint: Anterior tooth contact only on a flat surface perpendicular to the long axis of the mandibular incisor teeth • Stabilization splint : Uniform occlusal contact of the anterior and posterior teeth • Anterior repositioning splint : held the condyles slightly (0.5 – 1 mm anterior & inferior to the intercuspal position and had uniform occlusal contact of all teeth • Bilateral pivot splint: had pivots placed bilaterally between the second molars and had no other occlusal contacts • Unilateral pivot splint: had a pivot placed between the second molar one side of the dental arch www.indiandentalacademy.comwww.indiandentalacademy.com
    29. 29. Philosophiesfor Condylar Position  Bioaesthetics  Fixed numerical value based on incisal relationship  Distance between gingival margins of  18-20 mm in an unworn class I occlusion  upper incisal length of 12 mm  lower incisal length 10 mm,  4 mm overbite & 1 mm overjet  Gnathological  Fully adjustable articulator to determine condylar path from hinge axis  5 degree increase to ensure no posterior interferences www.indiandentalacademy.comwww.indiandentalacademy.com
    30. 30. Philosophiesfor condylar position when determining VD  Centric Relation based  Principles of P. Dawson  CR is defined prior to change in VD  Neuromuscular  Based on the principles of muscle activity determined by electromyography www.indiandentalacademy.comwww.indiandentalacademy.com
    31. 31. Centric Relation VsVertical Dimension Dawson’s technique: Prior to VD corrections, mandible has to be established in CR . The importance of CR as told by Dawson  Disk is properly aligned on both condyles  Condyle-disk assemblies are at the highest point possible against the posterior slopes of the eminentiae  Medial pole of each condyle-disk assembly is braced by bone  Superior lateral pterygoid muscle have released contraction and are passive  TMJs can accept firm compressive loading with no sign of tenderness or tension www.indiandentalacademy.comwww.indiandentalacademy.com
    32. 32. Centric Relation VsVertical Dimension  Condyles rotate in a fixed axis  Bite record made at any point of opening on correct centric relation arc is still in centric  Vertical Dimension can increased / decreased without introducing any error www.indiandentalacademy.comwww.indiandentalacademy.com
    33. 33. Diagnostic Waxup  Established VD  Measure VD : record dist. bw. 2 suitable gingival landmarks with calipers  Transfer VD to mounted diagnostic casts  Diagnostic waxup carried out www.indiandentalacademy.comwww.indiandentalacademy.com
    34. 34. Provisional Restorations - R.J. Ibbetson & D.J. Setchell 1989 Four Methods:  Use of anterior provisonals along with modified occlusal splint  Use of composite resin with anterior provisionals in place  Placing provisionals on posteriors first with modified anterior occlusal splint  Provisionals place both in anterior and posterior teeth www.indiandentalacademy.comwww.indiandentalacademy.com
    35. 35. www.indiandentalacademy.comwww.indiandentalacademy.com
    36. 36. www.indiandentalacademy.comwww.indiandentalacademy.com
    37. 37. www.indiandentalacademy.comwww.indiandentalacademy.com
    38. 38. www.indiandentalacademy.comwww.indiandentalacademy.com
    39. 39. Turner & Missirlian Category - 1 : Excessive wear with loss of VDO  Closest speaking space is more than 1 mm  Interocclusal space is more than 4 mm  Loss of facial contour  Drooping of the corners of the mouth Reliable method… .  Placement of trial restorations  Removable splint/ partial denture……..6 – 8 weeks  Fixed provisional restorations …. .. 2 – 3 months  All teeth of one arch must be prepared in a single sitting… ..  Less abrupt VDO  Better control of estheticswww.indiandentalacademy.comwww.indiandentalacademy.com
    40. 40. Turner & Missirlian Category - 2 : Excessive wear without loss of VDO but with space available  History of gradual wear ….  Bruxism  Moderate oral habits  Environmental factors  OVD maintained by continuous eruption  Tooth prep to establish retention & resistance form may be critical ….  Gingivo;lasty ….CLP  Enameloplasty of opposing posterior teeth… www.indiandentalacademy.comwww.indiandentalacademy.com
    41. 41. Turner & Missirlian Category - 3 : Excessive wear without loss of VDO but with limited space  Excessive wear of anterior teeth  Minimal wear of posterior teeth  CR = CO  Closest speaking space = 1 mm  Interocclusal distance = 2 -3 mm  Vertical Space obtained by  Orthodontic movement  Restorative repositioning  Surgical respositioning of segmentswww.indiandentalacademy.comwww.indiandentalacademy.com
    42. 42. PossibleClinical Concernsbehind changing VD  Joint / muscle Pain  < 1-2 weeks  Pain due to increased temporary muscle awareness  Stability  Relapse of restored VD variable without any fixed parameters  Muscle activity  VD increases EMG activity .. . Short lived  Postural muscle tone reduces with increased VD … normal within 3 months  Phonetics : ‘S’ sound  Increased VD shortens the lower incisors .. .ht has to restored  Also improved by restoring the palatal surface of the upper incisors www.indiandentalacademy.comwww.indiandentalacademy.com
    43. 43. ContraindicationsFor BiteRaising  Dense sclerotic bone  Hypertrophic Masticatory muscles www.indiandentalacademy.comwww.indiandentalacademy.com
    44. 44. Criteriafor Success!!! 1. Loading test 2. Clenching test 3. Grinding test 4. Fremitus 5. Stability test 6. Comfort test 7. Aesthetic test www.indiandentalacademy.comwww.indiandentalacademy.com
    45. 45. Loading Test  TMJ cant accept firm loading .. .. Condyles are braced by lateral pterygoid muscles / intracapsular disorder .. .. Instability of the TMJ  Trmt . not complete.. .. TMJ does not end up with complete comfort …. Maximal loading www.indiandentalacademy.comwww.indiandentalacademy.com
    46. 46. Clench Test  Perfected occlusion… . no sign of discomfort in any tooth / joint  Discomfort in any tooth .. . . Sure sign of premature / deflective contact  Clench test produces discomfort.. . Masticatory musculature…… occluso muscular disorder www.indiandentalacademy.comwww.indiandentalacademy.com
    47. 47. Grinding Test  Test…Posterior Interferences  Lack of posterior Disclusion  Post. Interference … hyperactivates elevator muscles  Occlusions with no anterior contacts in CR.. .. test modified to check the group function on the working side www.indiandentalacademy.comwww.indiandentalacademy.com
    48. 48. Fremitus Test  Light contact on the labial surfaces ….edge of fingernail….taps the teeth  Movement of any ant teeth …. tooth is in interference  Interference …. restrictive envelope of function/ failure to provide a needed “long centric”  Commonest cause: deflective posterior incline that forces the man forward into hard contact with the anterior teethwww.indiandentalacademy.comwww.indiandentalacademy.com
    49. 49. Stability Test  Refers to stable TMJ and stable dentition… . at least 3 months  Manageable stability  Joint Instability: Bone-to-bone TMJ contact in osteoarthritic breakdown of condyle/ eminence  Instable dentition:  Excessive wear of teeth  Hypermobility  Shifting of tooth position www.indiandentalacademy.comwww.indiandentalacademy.com
    50. 50. Comfort Test Complete Comfort of :  Teeth  Lips  Face Speech:  Comfortable  Cause no tiredness in facial & masticatory muscles Perfected Occlusion :  Peaceful neuromuscular system  Goal of all occlusal therapy www.indiandentalacademy.comwww.indiandentalacademy.com
    51. 51. Esthetic Test Patient should be happy with the appearance of the smile Functional harmony = Anatomic harmony Comfort test : Comfortable & unstrained speech Correctly placed incisal edges Harmony with the neutral zone www.indiandentalacademy.comwww.indiandentalacademy.com
    52. 52. CASE REPORTS – Bruxism  45-year-old male patient with a habit of bruxism  Attrition :  Marginally less in the posteriors as compared to the anterior teeth  Total collapse of the vertical dimension  Lower anterior teeth were totally razed to the gingival level  Upper lateral incisors & canines were also very badly destroyed www.indiandentalacademy.comwww.indiandentalacademy.com
    53. 53. CASE REPORTS  Second molars : Intercuspating occlusion  First molars : > 40% attrition on the occlusal surfaces with no intercuspation  Upper right lateral incisor & canine : attrided to the gingival level  Lower Anterior : Right first premolar - left canine were totally razed to gingival level  Remaining teeth : > 40% of loss of crown structure www.indiandentalacademy.comwww.indiandentalacademy.com
    54. 54. CASE REPORTS  Phase I  Endontic  Reestablishment of Vertical dimension  Occlusal equilibration  Phase II  CLP Upper and lower incisors Endodontics Glass fiber posts + Adhesive restorations  Post & core on upper right canine & lower canine www.indiandentalacademy.comwww.indiandentalacademy.com
    55. 55. CASE REPORTS www.indiandentalacademy.comwww.indiandentalacademy.com
    56. 56. AmelogenesisImperfecta  Incisal aspects …completely worn away exposing the pulp chambers  Occlusal aspects of all the posterior teeth were also severely worn  Cervical & proximal enamel was found to be normal  Attrition of the molars resulted in a decrease of the vertical dimension of occlusion  Interocclusal distance : At physiologic rest position = 7.3 mm  Centric Occlusion = Maximum intercuspal position  Gingival status: Good and well maintained  Oral hygiene : satisfactory www.indiandentalacademy.comwww.indiandentalacademy.com
    57. 57. CASE REPORTS Panoramic Radiographic Examination Enamel of the teeth appeared to have the same radiodensity as dentin Morphology of the roots were normal Pulp chambers were normal with no evidence of calcification Cementum, lamina dura, & bony trabeculations were within normal limits www.indiandentalacademy.comwww.indiandentalacademy.com
    58. 58. CASE REPORTS  Inadequate crown height for the fabrication of the prosthesis  Apically positioned flap  Crown lengthening  Increase of crown height by approximately 2 mm was achieved  Caries excavation was done for all carious teeth  Endodontic therapy was carried out as required  Bite registration using Type II modeling wax  Increased vertical dimension of 5 mm with 3 mm of freeway space  Splint fabricated with heat-cured Polymethyl methacrylate acrylic resin  Patient used the splint for three monthswww.indiandentalacademy.comwww.indiandentalacademy.com
    59. 59. CASE REPORTS  Full-mouth, heat-cured provisional restorations were fabricated at the desired vertical dimension (with 3 mm freeway space) using methyl methacrylate acrylic resin & were temporarily cemented www.indiandentalacademy.comwww.indiandentalacademy.com
    60. 60. CASE REPORTS  Maxillary anterior teeth: cast post cores  Mandibular anterior teeth : prefabricated posts  Premolars & right first molar : Composite core build-ups to increase the crown height Crown preparation: Porcelain-fused-to-metal (PFM) : Maxillary & mandibular anteriors, premolars, and maxillary first molars All-metal restorations: remaining teeth www.indiandentalacademy.comwww.indiandentalacademy.com
    61. 61. CASE REPORTS www.indiandentalacademy.comwww.indiandentalacademy.com
    62. 62. Conclusion!!! Most patients with severe wear of teeth can be managed by restoring the occlusion and without increasing the vertical dimension. If the VDO has to be increased, such as in Turner and Missirlian class-III situation, it has to be done cautiously. According to literature, a limited increase in vertical height can be tolerated and well adapted. The amount of vertical height to be increased is best judged by placing removable splint/denture and fixed provisional restorations. The final restoration should mimic the OVD, function, and esthetics that have been developed in the fixed provisional restoration. www.indiandentalacademy.comwww.indiandentalacademy.com
    63. 63. “ You cannot successfully treat dysfunction unless you understand function” www.indiandentalacademy.comwww.indiandentalacademy.com
    64. 64. References : D. R. Bloom 1 and J . N. Padayachy , Increasing occlusal vertical dimension — Why, when and how , BDJ, 2006,200:251-256  B. H. Smith, Changes in occlusal face height with removable partial prostheses, JPD 1975; 34(3) : 279-285  Turner KA, Missirlian DM. Restoration of the extremely worn dentition. J Prosthet Dent 1985;52:467-74.    Krishna MG, Rao KS, Goyal K, Prosthodontic management of severely worn dentition: including review of literature related to physiology and pathology of increased vertical dimension of occlusion. J Prosthet Dent 2005 ; 5(2): 89-93  Dawson PE. Evaluation, Diagnosis, and Treatment of Occlusal Problems, ed 2. St Louis: Mosby, 1989. www.indiandentalacademy.comwww.indiandentalacademy.com
    65. 65. References :  Okeson JP, Management of Temporomandibular Disorders and Occlusion, ed 4. St Louis: Mosby, 1998:160.  Araki A, Yokoyama T, Murakamu H, Ito Y, Maeda H, Kameyama Y. Effect of decreased vertical occlusion on mandibular condyle of senescence-accelerated mouseP8 [abstract 706]. J Dent Res 1999;78:194.  Richard P. Harper, Clinical Indications for Altering Vertical Dimension of Occlusion , Quintessence International, Vol 31, No 4 (April 2000) www.indiandentalacademy.comwww.indiandentalacademy.com
    66. 66. THANK YOUTHANK YOU www.indiandentalacademy.comwww.indiandentalacademy.com
    67. 67. Journal Club 14th June 2008 by Dr. abhilasha next !!!www.indiandentalacademy.comwww.indiandentalacademy.com
    68. 68. Guidemand to centric relation in dentulous situation A. Operator guided methods: manual guidance  Chin Point guidance – Guichet (1970): thumb & forefinger positions the condyle in RUM position  Bimanual method – Peter Dawson (1974): guides the mandible in most superior anterior position  Three Finger method – Peter Thomas 1980: Positions condyle in anterior superior position A. Anterior Deprogrammer  Uses of Leaf Gauge:  Helps to deprogram the muscles and tripodizes the mandible for obtaining centric interocclusal record by assisting the patient’s neuromusculature to seat the condyles in anterior superior position  Useful to detect centric prematurities in dentulous subjects  Useful in TMJ dysfunction to eliminate muscle memory or engram. It helps to identify occlusal prematurities and also to indicate the optimum vertical height www.indiandentalacademy.comwww.indiandentalacademy.com
    69. 69. www.indiandentalacademy.comwww.indiandentalacademy.com

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