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Wolff’s law Presentation Transcript

  • 1. WOLFF’S LAWWOLFF’S LAW INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  • 2.  In the early 1990s German physiologist WolffIn the early 1990s German physiologist Wolff demonstrated that bony trabeculae weredemonstrated that bony trabeculae were arranged in response to stress lines on the bone.arranged in response to stress lines on the bone.  Bone is formed in just the quantity and shapeBone is formed in just the quantity and shape that will enable it to withstand the physicalthat will enable it to withstand the physical demands made upon it, with the greatestdemands made upon it, with the greatest amount of economy of structure.amount of economy of structure. www.indiandentalacademy.com
  • 3.  If a long bone such as the femur is cut open, itIf a long bone such as the femur is cut open, it will be found that dense cortical bone is on thewill be found that dense cortical bone is on the outside and the spicules of cancellous boneoutside and the spicules of cancellous bone within are arranged in such a way that theywithin are arranged in such a way that they support the cortical bone along well definedsupport the cortical bone along well defined paths of stress and strain.paths of stress and strain. www.indiandentalacademy.com
  • 4. www.indiandentalacademy.com
  • 5. MYOTONIC APPLIANCEMYOTONIC APPLIANCE  Rely on muscle mass and resting pressureRely on muscle mass and resting pressure  This was achieved by-This was achieved by- 1. increasing the interocclusal distance with the1. increasing the interocclusal distance with the construction biteconstruction bite 2. immobilizing the appliance ( eg adding clasp2. immobilizing the appliance ( eg adding clasp on lateral maxillary teeth- Herren )on lateral maxillary teeth- Herren ) 3. increase in dislocation of mandible in vertical3. increase in dislocation of mandible in vertical and saggital direction.and saggital direction. www.indiandentalacademy.com
  • 6. MYODYNAMIC APPLIANCEMYODYNAMIC APPLIANCE  Make use of muscle activity and movement.Make use of muscle activity and movement. 1. H. P. Bimler - found the possibility of1. H. P. Bimler - found the possibility of expanding the maxillary arch by crosswiseexpanding the maxillary arch by crosswise transmission of transverse mandible movements.transmission of transverse mandible movements. 2. features of elastischer gebissformer-2. features of elastischer gebissformer- a. could be worn during the entire daya. could be worn during the entire day b. elasticity help translate muscle movementb. elasticity help translate muscle movement to dentition and supporting tissueto dentition and supporting tissue www.indiandentalacademy.com
  • 7. CONTRACTILITY OF MUSCLECONTRACTILITY OF MUSCLE  Classified into two types based on change in theClassified into two types based on change in the length of muscle fiber or tension of the muscle-length of muscle fiber or tension of the muscle- 1. Isotonic contraction- tension remains the1. Isotonic contraction- tension remains the same and change occurs in the length of musclesame and change occurs in the length of muscle fiber. eg. Simple flexion of armfiber. eg. Simple flexion of arm 2. Isometric contraction- length of muscle fiber2. Isometric contraction- length of muscle fiber remains the same and the tension is increased.remains the same and the tension is increased. eg. Pulling any heavy objecteg. Pulling any heavy object www.indiandentalacademy.com
  • 8. CLASSIFICATION OFCLASSIFICATION OF FUNCTIONALFUNCTIONAL APPLIANCESAPPLIANCES www.indiandentalacademy.com
  • 9.  1. a. Tooth borne passive appliance-1. a. Tooth borne passive appliance- have no intrinsic force generating componenthave no intrinsic force generating component such as spring or screw. They depend on softsuch as spring or screw. They depend on soft tissue stretch and muscle activity to produce thetissue stretch and muscle activity to produce the desired treatment results.desired treatment results. eg. Activatoreg. Activator www.indiandentalacademy.com
  • 10. b. Tooth borne active appliance-b. Tooth borne active appliance- include modification of activator and bionatorinclude modification of activator and bionator that include expansion screw or other activethat include expansion screw or other active components like springs.components like springs. c. Tissue borne passive appliance-c. Tissue borne passive appliance- located in the vestibule and have little or nolocated in the vestibule and have little or no contact with the dentition.contact with the dentition. eg. Functional regulator of Frankeleg. Functional regulator of Frankel www.indiandentalacademy.com
  • 11.  2. a. Myotonic appliance2. a. Myotonic appliance b. Myodynamic applianceb. Myodynamic appliance www.indiandentalacademy.com
  • 12.  4. Group 1 appliance-4. Group 1 appliance- they transmit the muscle force directly to the teeththey transmit the muscle force directly to the teeth for the purpose of correction of malocclusion.for the purpose of correction of malocclusion. eg. Oral screen and inclined planes ( oppenheim splint)eg. Oral screen and inclined planes ( oppenheim splint) Group 2 appliance-Group 2 appliance- they reposition the mandible and the resultant force isthey reposition the mandible and the resultant force is transmitted to the teeth and other structuretransmitted to the teeth and other structure eg. Activator and bionatoreg. Activator and bionator www.indiandentalacademy.com
  • 13.  Group 3 appliance-Group 3 appliance- they also reposition the mandible, but the areathey also reposition the mandible, but the area of operation is the vestibule.of operation is the vestibule. eg. Frankel appliance and vestibular screeneg. Frankel appliance and vestibular screen www.indiandentalacademy.com
  • 14.  3. a. Removable functional appliance3. a. Removable functional appliance b. Fixed functional applianceb. Fixed functional appliance www.indiandentalacademy.com
  • 15.  The bite is not opened beyond the postural restThe bite is not opened beyond the postural rest position. This stimulates myotactic reflex activityposition. This stimulates myotactic reflex activity causing isometric contractions. This muscularcausing isometric contractions. This muscular reflex is transmitted to the teeth through thereflex is transmitted to the teeth through the appliance. Thus the appliance works by makingappliance. Thus the appliance works by making use of the kinetic energy.use of the kinetic energy.  This original concept and working hypothesis ofThis original concept and working hypothesis of Andresen and Haupl was accepted by manyAndresen and Haupl was accepted by many authorities but rejected by some.authorities but rejected by some. www.indiandentalacademy.com
  • 16. THE BITE OPENINGTHE BITE OPENING CONTROVERSYCONTROVERSY  By introducing a new path of closure, theBy introducing a new path of closure, the activator causes musculoskeletal adaptation. Thisactivator causes musculoskeletal adaptation. This adaptation process caused by the activator alsoadaptation process caused by the activator also includes an effect on the condyle.includes an effect on the condyle.  The condyle grow in an upward and backwardThe condyle grow in an upward and backward direction to maintain the integrity of the TMJdirection to maintain the integrity of the TMJ structures. Such an adaptation is caused by thestructures. Such an adaptation is caused by the loose fitting appliance.loose fitting appliance. www.indiandentalacademy.com
  • 17.  Rolf Grude in 1952 gave an explanation for theRolf Grude in 1952 gave an explanation for the continuing controversies. He said that the modecontinuing controversies. He said that the mode of action of activator as said by Andresen andof action of activator as said by Andresen and Haupl can be seen only if the mandible is notHaupl can be seen only if the mandible is not displaced beyond the postural rest position. Ifdisplaced beyond the postural rest position. If the mandible is opened beyond the rest positionthe mandible is opened beyond the rest position or the 4 mm limit the mode of action is quietor the 4 mm limit the mode of action is quiet different.different. www.indiandentalacademy.com
  • 18.  The appliance works by the viscoelasticThe appliance works by the viscoelastic properties of the muscles or by stretching of theproperties of the muscles or by stretching of the soft tissues and not by the Andresen and Hauplsoft tissues and not by the Andresen and Haupl concept. However since the interocclusalconcept. However since the interocclusal clearance varies from patient to patient and alsoclearance varies from patient to patient and also in the same individual from time to time thein the same individual from time to time the statements of Grude are made with reservations.statements of Grude are made with reservations. www.indiandentalacademy.com
  • 19.  1. Petrovic and McNamara support the1. Petrovic and McNamara support the Andresen and Haupl concept and have gotAndresen and Haupl concept and have got results which indicate that a more favorableresults which indicate that a more favorable condylar response to activator treatment may becondylar response to activator treatment may be possible if through action of the appliance apossible if through action of the appliance a proper stimulus is provided. The stimulus fromproper stimulus is provided. The stimulus from the appliance, muscle receptors and the PDthe appliance, muscle receptors and the PD mechanoreceptors promote displacement of themechanoreceptors promote displacement of the mandible.mandible. www.indiandentalacademy.com
  • 20.  Both Petrovic and McNamara have shown theBoth Petrovic and McNamara have shown the great imp. of lateral pterygoid muscle for thegreat imp. of lateral pterygoid muscle for the forward growth of the mandible. An applianceforward growth of the mandible. An appliance which holds the mandible rigidly in a forwardwhich holds the mandible rigidly in a forward direction doesn’t stimulate lateral pterygoiddirection doesn’t stimulate lateral pterygoid activity which in turn does not stimulateactivity which in turn does not stimulate condoyle growth. Based on this researchcondoyle growth. Based on this research Petrovic and McNamara support the viewPetrovic and McNamara support the view www.indiandentalacademy.com
  • 21.  that variation in the mode and direction ofthat variation in the mode and direction of dislocation of the mandible are decisive factorsdislocation of the mandible are decisive factors in activator Tt.in activator Tt.  2. A second group of authors ( Selmer-Olsen,2. A second group of authors ( Selmer-Olsen, Herren, Harvold and Woodside) do not supportHerren, Harvold and Woodside) do not support the theory of myotactic reflex activity withthe theory of myotactic reflex activity with isometric muscle contractions as stipulated byisometric muscle contractions as stipulated by Andresen. Selmer-Olsen says that muscle activityAndresen. Selmer-Olsen says that muscle activity cannot be stimulated at night becausecannot be stimulated at night because www.indiandentalacademy.com
  • 22.  nature has designed them to rest during sleep.nature has designed them to rest during sleep. He says that, the mandible assumes a position ofHe says that, the mandible assumes a position of equilibrium at night. An opening beyond thisequilibrium at night. An opening beyond this position requires active work from the openingposition requires active work from the opening muscle to overcome the resistance of themuscle to overcome the resistance of the stretched fibers in the soft tissues. If a foreignstretched fibers in the soft tissues. If a foreign body is inserted between the jaws keeping thebody is inserted between the jaws keeping the mandible beyond the equilibrium position, themandible beyond the equilibrium position, the closing muscles remain stretched.closing muscles remain stretched. www.indiandentalacademy.com
  • 23.  A pressure is exerted against the foreign bodyA pressure is exerted against the foreign body through the teeth. Hence, the tooth moving forces inthrough the teeth. Hence, the tooth moving forces in activator therapy are not due to muscle forces oractivator therapy are not due to muscle forces or kinetic energy but by a stretching of soft tissues orkinetic energy but by a stretching of soft tissues or potential energy.potential energy.  Woodside calls this viscoelastic property. HerrenWoodside calls this viscoelastic property. Herren analyzed the activators mode of action on the basisanalyzed the activators mode of action on the basis of the spatial relationship between the mandible andof the spatial relationship between the mandible and postural rest position. He states that the activatorpostural rest position. He states that the activator does not work in the way postulated by Andresendoes not work in the way postulated by Andresen even if the caudal displacement is less than 3 mm.even if the caudal displacement is less than 3 mm. www.indiandentalacademy.com
  • 24.  Such an appliance does not increase frequency ofSuch an appliance does not increase frequency of closing movements. Herren overextends in the saggitalclosing movements. Herren overextends in the saggital direction bringing the mandible in andirection bringing the mandible in an edge to edge incisal relationship. According to him,edge to edge incisal relationship. According to him, when an activator is inserted in the mouth, it restrictswhen an activator is inserted in the mouth, it restricts the mandible from assuming any lateral protrusive orthe mandible from assuming any lateral protrusive or retrusive rest positions normally assumed during sleep.retrusive rest positions normally assumed during sleep. The forces which pull the appliance towards these restThe forces which pull the appliance towards these rest position are absorbed by the appliance and transmittedposition are absorbed by the appliance and transmitted to the teeth and alveolar processes.to the teeth and alveolar processes. www.indiandentalacademy.com
  • 25.  These are the teeth moving forces. According toThese are the teeth moving forces. According to Herren, mandible movements do occur, butHerren, mandible movements do occur, but forces created thereby are of minor importance.forces created thereby are of minor importance. According to Harvold-Woodside the mandibleAccording to Harvold-Woodside the mandible normally drops open when the patient is asleep.normally drops open when the patient is asleep. Interocclusal clearance is more during sleep andInterocclusal clearance is more during sleep and hence there is a chance that the appliance willhence there is a chance that the appliance will not be retained in the mouth and no skeletal ornot be retained in the mouth and no skeletal or dental changes can be expected.dental changes can be expected. www.indiandentalacademy.com
  • 26.  He states that high construction bites as much asHe states that high construction bites as much as 10-15 mm beyond the postural rest position10-15 mm beyond the postural rest position spreads the jaws apart. The effect is a stretchingspreads the jaws apart. The effect is a stretching of the elevators and retractors of the mandible.of the elevators and retractors of the mandible. The forces thereby created transmitted to theThe forces thereby created transmitted to the teeth and alveolar processes.teeth and alveolar processes. www.indiandentalacademy.com
  • 27.  3. Between the two extremes there are many who take a3. Between the two extremes there are many who take a higher construction bite without the extreme sagittalhigher construction bite without the extreme sagittal extension advocated by Herren. These authors includeextension advocated by Herren. These authors include Schmuth, Witt and Komposch. Eschler says that if theSchmuth, Witt and Komposch. Eschler says that if the bite is opened 4-6mm beyond postural rest position, thebite is opened 4-6mm beyond postural rest position, the appliance works alternately with isometric and isotonicappliance works alternately with isometric and isotonic muscle contraction. At insertion of the appliance,muscle contraction. At insertion of the appliance, isotonic muscle contraction cause elevation of theisotonic muscle contraction cause elevation of the mandible. When the mandible contacts the appliancemandible. When the mandible contacts the appliance isometric contraction begins.isometric contraction begins. www.indiandentalacademy.com
  • 28.  The elevators remain stretched as the mandible cannotThe elevators remain stretched as the mandible cannot assume its rest position. As they fatigue the contractionassume its rest position. As they fatigue the contraction cease and the mandible drops down. After recovery, thecease and the mandible drops down. After recovery, the same cycle is repeated.same cycle is repeated. In conclusion, there are two main theories regardingIn conclusion, there are two main theories regarding the activators mode of action. According to the first,the activators mode of action. According to the first, loose appliance stimulates the muscle and it is theloose appliance stimulates the muscle and it is the activator in motion that moves the teeth. The forces areactivator in motion that moves the teeth. The forces are intermittent in nature hitting the teeth as jolts. Theintermittent in nature hitting the teeth as jolts. The elevator of mandible and other units of orofacialelevator of mandible and other units of orofacial complex have to do active work in order to keep thecomplex have to do active work in order to keep the activator in place.activator in place. www.indiandentalacademy.com
  • 29.  It is a prerequisite for such a mode of action that theIt is a prerequisite for such a mode of action that the mandible is not displaced beyond the postural restmandible is not displaced beyond the postural rest position.position. The other hypothesis says that it is the activator atThe other hypothesis says that it is the activator at rest which moves the teeth. The appliance is squeezedrest which moves the teeth. The appliance is squeezed between the jaws. In such a position it exerts abetween the jaws. In such a position it exerts a continuous pressure against teeth. However the forcecontinuous pressure against teeth. However the force application is interrupted every time the activator isapplication is interrupted every time the activator is removed from the mouth.removed from the mouth. www.indiandentalacademy.com
  • 30.  The periodicity thereby introduced is calledThe periodicity thereby introduced is called ‘‘ big intermittence’. When the appliance is in thebig intermittence’. When the appliance is in the mouth force application may be interrupted formouth force application may be interrupted for a single tooth or a group of teeth. Thisa single tooth or a group of teeth. This periodicity is called the ‘little intermittence’periodicity is called the ‘little intermittence’ www.indiandentalacademy.com
  • 31. CONSTRUCTION BITECONSTRUCTION BITE  The positioning of the mandible in preparationThe positioning of the mandible in preparation for the fabrication of functional appliance isfor the fabrication of functional appliance is considered in three planes of space-considered in three planes of space- verticalvertical horizontalhorizontal transversetransverse www.indiandentalacademy.com
  • 32.  The vertical opening of the mandible dependsThe vertical opening of the mandible depends on the following things-on the following things- 1. the kind of dysgnathic or dysplastic problem1. the kind of dysgnathic or dysplastic problem ( sagittal or vertical relationship)( sagittal or vertical relationship) 2. the developmental state, age and sex of patient2. the developmental state, age and sex of patient (potential incremental changes)(potential incremental changes) 3. the type of activator to be used3. the type of activator to be used www.indiandentalacademy.com
  • 33.  Different sagittal and vertical dysplasia requireDifferent sagittal and vertical dysplasia require different construction bite registration.different construction bite registration. 1. Deep bite Class II Div 2 malocclusion1. Deep bite Class II Div 2 malocclusion 2. Class III malocclusion2. Class III malocclusion It is necessary to record the vertical distanceIt is necessary to record the vertical distance between the incisal margins of upper and lowerbetween the incisal margins of upper and lower incisor edges when determining how wide theincisor edges when determining how wide the construction bite should be.construction bite should be. www.indiandentalacademy.com
  • 34.  Class II Div 2 and Class III- 1.5- 3 mmClass II Div 2 and Class III- 1.5- 3 mm  Mixed Dentition- 4 – 7mmMixed Dentition- 4 – 7mm  Severe Class II Div 2 – upto 9mmSevere Class II Div 2 – upto 9mm 1. Woodside philosophy1. Woodside philosophy 2. brings the mandible out of the range of any2. brings the mandible out of the range of any tooth guidance and the resultant retrusive effecttooth guidance and the resultant retrusive effect on the condyle and the path of closureon the condyle and the path of closure 3. horizontal growth pattern/ forward and3. horizontal growth pattern/ forward and upward rotating pattern- deepening of biteupward rotating pattern- deepening of bite www.indiandentalacademy.com
  • 35. www.indiandentalacademy.com
  • 36.  In a full Class II Div 1 malocclusion with aIn a full Class II Div 1 malocclusion with a protrusion of upper incisor and deep overbite,protrusion of upper incisor and deep overbite, the opening of bite is dependant on how muchthe opening of bite is dependant on how much anterior posturing is necessary to establish aanterior posturing is necessary to establish a normal sagittal relationship.normal sagittal relationship. 1.1. If lessIf less 2.2. If significantIf significant www.indiandentalacademy.com
  • 37. www.indiandentalacademy.com
  • 38.  Class II Div 1 malocclusion in whichClass II Div 1 malocclusion in which 1. sagittal malrelation is the width of a premolar1. sagittal malrelation is the width of a premolar 2. severe curve of Spee2. severe curve of Spee 3. lower incisors are over erupted and impinge3. lower incisors are over erupted and impinge on the palatal mucosaon the palatal mucosa Construction bite should not be higher than theConstruction bite should not be higher than the vertical edge to edge incisor relationship.vertical edge to edge incisor relationship. www.indiandentalacademy.com
  • 39. www.indiandentalacademy.com
  • 40.  Considerations for horizontal posturing of the mandible-Considerations for horizontal posturing of the mandible- 1.1. Original sagittal jaw relationship may be maintained, as inOriginal sagittal jaw relationship may be maintained, as in neutroclusion with a class II type of incisor overjet and deepneutroclusion with a class II type of incisor overjet and deep bite or in a similar Class II relationship due to maxillarybite or in a similar Class II relationship due to maxillary protractionprotraction 2.2. The mandible may be postured forward to change the sagittalThe mandible may be postured forward to change the sagittal relationship equally on both sides when the problem is arelationship equally on both sides when the problem is a bilaterally symmetrical Class II condition.bilaterally symmetrical Class II condition. 3.3. The bite is changed on one side but is maintained as much asThe bite is changed on one side but is maintained as much as possible on the other side- unilateral casepossible on the other side- unilateral case 4.4. The mandible is postured backward as much as possible in theThe mandible is postured backward as much as possible in the fossa, opening the bite enough to try for an end to end incisalfossa, opening the bite enough to try for an end to end incisal relationship as in Class III malocclusion.relationship as in Class III malocclusion. www.indiandentalacademy.com
  • 41. www.indiandentalacademy.com
  • 42.  Conditions in which mandible is not postured forwardConditions in which mandible is not postured forward while constructing the bite-while constructing the bite-  1. Class II malocclusion due to mesial positioning of1. Class II malocclusion due to mesial positioning of the maxilla itself or of the dental arches, pulled forwardthe maxilla itself or of the dental arches, pulled forward by a prolonged finger sucking habit.( extract)by a prolonged finger sucking habit.( extract)  2. Class I with cross bite of individual or all incisors.2. Class I with cross bite of individual or all incisors. ( downward and backward)( downward and backward)  3. Class II malocclusion in which there is mesial3. Class II malocclusion in which there is mesial positioning or displacement from postural rest topositioning or displacement from postural rest to occlusion. Mandible closes upward and excessivelyocclusion. Mandible closes upward and excessively forward under tooth guidence, instead of beingforward under tooth guidence, instead of being functionally retruded ( bimax)functionally retruded ( bimax) www.indiandentalacademy.com
  • 43. Degree of mandible advancement-Degree of mandible advancement- Newmann – advances mandible to a width of anNewmann – advances mandible to a width of an entire toothentire tooth  Frankel – stepwise advancementFrankel – stepwise advancement  Eschler – greatest possible advancement withEschler – greatest possible advancement with which the patient can be comfortable.which the patient can be comfortable. www.indiandentalacademy.com
  • 44. CONSTRUCTION BITECONSTRUCTION BITE REGISTRATIONREGISTRATION  In miixed dentition it is sometimes difficult toIn miixed dentition it is sometimes difficult to determine precisely how much the mandible hasdetermine precisely how much the mandible has been moved forward in the construction bitebeen moved forward in the construction bite because of the wax roll covering the toothbecause of the wax roll covering the tooth contact surface-contact surface- use deciduous canine/upper first premolar as ause deciduous canine/upper first premolar as a guideguide www.indiandentalacademy.com
  • 45. www.indiandentalacademy.com
  • 46. MIDLINE CONSIDERATIONSMIDLINE CONSIDERATIONS  If the upper and lower midline are coincident inIf the upper and lower midline are coincident in the habitual occlusion and the sagittalthe habitual occlusion and the sagittal relationship is bilaterally symmetrical then therelationship is bilaterally symmetrical then the midlines should line up in forward posturing inmidlines should line up in forward posturing in the same relationship as in habitual occlusion.the same relationship as in habitual occlusion. For this was is cut away in the midline to makeFor this was is cut away in the midline to make sure that the posturing forward has not allowedsure that the posturing forward has not allowed the mandible to deviate to one side or the other.the mandible to deviate to one side or the other. www.indiandentalacademy.com
  • 47.  If the upper and lower midlines do not coincide-If the upper and lower midlines do not coincide- premature loss of deciduous caninepremature loss of deciduous canine occlusal interferenceocclusal interference Construction bite should follow the midlines ofConstruction bite should follow the midlines of the maxilla and mandible, regardless of thethe maxilla and mandible, regardless of the shifting of teeth in one jaw or the other.shifting of teeth in one jaw or the other. www.indiandentalacademy.com
  • 48. CONSTRUCTION BITECONSTRUCTION BITE TECHNIQUETECHNIQUE  Patient compliance is essentialPatient compliance is essential this can be achieved by asking the pt to advancethis can be achieved by asking the pt to advance the mandible in case of Class II malocclusion tothe mandible in case of Class II malocclusion to create an instant correction. The pt sees thecreate an instant correction. The pt sees the potential and objectives of the correction to bepotential and objectives of the correction to be brought about by the functional appliance and isbrought about by the functional appliance and is more likely to work towards this goal of estheticmore likely to work towards this goal of esthetic improvement as compared to dental health andimprovement as compared to dental health and functional improvement.functional improvement. www.indiandentalacademy.com
  • 49.  1. STUDY MODEL ANALYSIS1. STUDY MODEL ANALYSIS a. the first molar relationship in habitual occlusion isa. the first molar relationship in habitual occlusion is determineddetermined b. nature of midline discrepancy if any is determinedb. nature of midline discrepancy if any is determined c. symmetry of dental arches is determined- asymmetryc. symmetry of dental arches is determined- asymmetry such as segmental open bite can be corrected with ansuch as segmental open bite can be corrected with an activatoractivator d. the curve of Spee is checked to see if can or should bed. the curve of Spee is checked to see if can or should be leveled with the appliance.leveled with the appliance. www.indiandentalacademy.com
  • 50.  2. FUNCTIONAL ANALYSIS2. FUNCTIONAL ANALYSIS a.a. Precise registration of the ret position is made as thePrecise registration of the ret position is made as the vertical opening of the construction bite depends onvertical opening of the construction bite depends on thisthis b.b. Path of closure from postural rest to habitualPath of closure from postural rest to habitual occlusion is analyzed.occlusion is analyzed. c.c. Prematurities, occlusal interferences and mandibularPrematurities, occlusal interferences and mandibular displacement if any are checkeddisplacement if any are checked www.indiandentalacademy.com
  • 51. d. Interoccluasal clearance is checked several timesd. Interoccluasal clearance is checked several times and the mean amount is recordedand the mean amount is recorded e. TMJ should be palpated for clicking, crepituse. TMJ should be palpated for clicking, crepitus ect. Which may lead to modification in theect. Which may lead to modification in the applianceappliance f. Respiration assesmentf. Respiration assesment www.indiandentalacademy.com
  • 52.  3. CEPHALOMETRIC ANALYSIS3. CEPHALOMETRIC ANALYSIS a. direction of growth- average, horizontal or vertical isa. direction of growth- average, horizontal or vertical is determineddetermined b. the difference between the position and the size ofb. the difference between the position and the size of the jaw bases is determinedthe jaw bases is determined c. the axial inclination and the position of maxillary andc. the axial inclination and the position of maxillary and mandibular incisors are determined. This provides imp.mandibular incisors are determined. This provides imp. diagnostic and prognostic clues for determining thediagnostic and prognostic clues for determining the anterior positioning of the mandible and the applianceanterior positioning of the mandible and the appliance design detail for the incisor area.design detail for the incisor area. www.indiandentalacademy.com
  • 53. CONSTRUCTION BITECONSTRUCTION BITE PLANNINGPLANNING  On the basis of inf. gathered the extent of ant.On the basis of inf. gathered the extent of ant. positioning for Class II malocclusions and post.positioning for Class II malocclusions and post. positioning for Class III malocclusions ispositioning for Class III malocclusions is determined.determined. www.indiandentalacademy.com
  • 54. www.indiandentalacademy.com
  • 55.  Ant. positioning of this magnitude is contraindicatedAnt. positioning of this magnitude is contraindicated in-in- a.a. If the overjet is too large( 18 mm), then anteriorIf the overjet is too large( 18 mm), then anterior positioning is a stepwise progression accompanied inpositioning is a stepwise progression accompanied in two or three phases.two or three phases. b.b. If there is severe labial tipping of maxillary incisors,If there is severe labial tipping of maxillary incisors, they should be uprighted first, if possible, by athey should be uprighted first, if possible, by a prefunctional appliance.prefunctional appliance. c.c. Pathological construction bite in case of in case ofPathological construction bite in case of in case of palatal eruption of incisor.palatal eruption of incisor. www.indiandentalacademy.com
  • 56. www.indiandentalacademy.com
  • 57.  Principles in maintaining a proper horizontal-Principles in maintaining a proper horizontal- vertical relationship and determining the heightvertical relationship and determining the height of the bite-of the bite- a.a. The mandible must be dislocated from the restThe mandible must be dislocated from the rest position in atleast one direction. This isposition in atleast one direction. This is essential in order to activate the associatedessential in order to activate the associated musculature and induce strain in tissue.musculature and induce strain in tissue. b.b. Inverse relation between forward positioningInverse relation between forward positioning and vertical opening.and vertical opening. www.indiandentalacademy.com
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  • 61. Execution of construction biteExecution of construction bite techniquetechnique www.indiandentalacademy.com
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  • 69. www.indiandentalacademy.com Thank you For more details please visit www.indiandentalacademy.com