Occlusal Registration in Removable Partial Denture / orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY

Leader in continuing dental education www.indiandentalacademy.comwww.indiandentalacademy.com

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OCCLUSAL REGISTRATION IN REMOVABLE PARTIAL DENTUREwww.indiandentalacademy.com


OCCLUSIONThe static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth or tooth analogues. (GPT-7)



CENTRIC RELATIONThe maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anterior-superior position against the shape of the articular eminences. This position is independent of tooth contact. This position is clinically discernible when the mandible is directed superior and anteriorly.it is restricted to a purely rotary movement about a transverse horizontal axis.(GPT-7)



CENTRIC OCCLUSIONThe occlusion of opposing teeth when the mandible is in centric relation.(GPT-7)



MAXIMAL INTERCUSPAL POSITIONThe complete intercuspation of the opposing teeth independent of condylar position, sometimes referred to as the best fit of the teeth regardless of the condylar position.(GPT-7)



VERTICAL DIMENSIONThe distance between two selected points, one on a fixed and one on a movable member.

OCCLUSAL VERTICAL DIMENSION : the distance between two points when the occluding members are in contact.



PHYSILOGICAL REST POSITION :the mandibular position assumed when the head is in an upright position and the involved muscles, particularly the elevators and depressor groups, are in equilibrium and tonic contraction, the condyles are in a neutral, unstrained position.(GPT-7)



OCCLUSAL REGISTRATIONA registration of the positional relationship of apposing teeth or arches; a record of the positional relationship of the teeth or jaws to each other.(GPT-7)



OBJECTIVES:To establish & maintain a harmonious relationship with all oral structures & to provide a masticatory apparatus which is efficient, comfortable & esthetically pleasing. Necessary for distribution of functional forces evenly as possible to all supporting structures within their capability of withstanding the stress. www.indiandentalacademy.com


A harmonious occlusion contributes materially to the control of damaging, leverage induced stresses where as a faculty occlusion compounds the destructive forces.www.indiandentalacademy.com


IDEAL REQUIREMENTS OF BITE REGISTRATION MATERIAL Limited resistance before setting to avoid displacing the teeth or mandible during closure.Rigid or resilient after setting.Minimal dimensional change after setting.Ideal recording of occlusal & incisal surface of the teeth.www.indiandentalacademy.com


Easy to manipulate.

No adverse effects on the tissues involved in recording procedures.

Interocclusal record should be verifiable. www.indiandentalacademy.com


IMPRESSION PLASTERBasically plaster of Paris in which modifiers have been added. Modifiers accelerates setting time &decreases setting expansion.



ADVANTAGES:Accurate.Rigid after setting.Do not distort after extended storage.www.indiandentalacademy.com


DISADVANTAGES:Difficult to handle because the material is unmanageable prior to setting.The final interocclusal record is brittle.www.indiandentalacademy.com


WAXESThermoplastic waxes are frequently used for interocclusal registration as records or as a carrier for registration.Wax is widely accepted as an interocclusal recording material.



ADVANTAGES:Easy to manipulate

DISADVANTAGES:InaccurateUnstableInconsistent due to interference with passive and active movements of mandible.



ZINC OXIDE EUGENOL PASTESIs an effective interocclusal registration materialADVANTAGESFluidity before setting. Fluidity is a critical quality of an occlusal registration material because it ensures minimal interference with mandibular closure during record making procedures.



Adhesion to its carrierRigidity and inelasticity after final setAccuracy in recording occlusal and incisal surfaces of the teethHigh degree of repeatability



DISADVANTAGESLengthy setting timeSignificant brittlenessThe accuracy of the registration material may surpass the accuracy of the casts, resulting in improper fit.



SILICONE ELASTOMERS

Two types of silicone elastomers are available as interocclusal registration materialsCondensation siliconeAdditional silicone

Currently, additional silicone has gained acceptance because it is more stable than condensation siliconewww.indiandentalacademy.com


ADVANTAGES:AccuracyStability after settingMinimal resistance to closureDoes not require a carrier

DISADVANTAGES:its resistance to compression of the set material ,which contributes to difficulty in seating of plaster cast



POLYETHER ELASTOMERSThese were introduced to dentistry in the early 1970s.Poly ether interocclusal registration material consists of the basic impression material augmented by plasticizers and fillers



ADVANTAGES:AccuracyStability after polymerization and during storageFluidity and minimal resistance to closurePolyether can be used without a carrier



DISADVANTAGESResiliency and accuracy may exceed the accuracy of the plaster casts. Both of these factors can interfere with the placement of the plaster cast into the recording medium during mounting procedures.

The records are trimmed to remove excess material and preserve only the teeth indentations, avoiding distortions.



ACRYLIC RESINSThe most frequent application of acrylic resins for interocclusal records is in the fabrication of single stop centric occlusion records

ADVANTAGESAccurateRigid after setting



DISADVANTAGES:

Dimensional instability of some commercial formulations due to continued polymerization resulting in shrinkage.

The strength and rigidity of the material can damage plaster cast and dies during articulator mounting.



STABILIZED BITE RIMSStabilized rims may be constructed on the replicas of the diagnostic cast. The rims are transferred to the mouth and the centric closure position recorded.Stabilized rims are indicated for the positioning the cast prior to the formation of the treatment plan and tooth preparation.



LaDeane Fattore ,William F.malone and associates conducted a study to compare the clinical accuracy of various inter occlusal recording materials (JPD 1984:51(2) 152-157) .THEY COMPARED

Two thickness pink base plate wax Reinforced waxZinc -oxide eugenol paste A modified ,non rigid poly ether recording medium with a carrierPoly ether without a carrier www.indiandentalacademy.com


AND they concluded thatPolyether inter occlusal recording medium without a carrier was the most accuratePolyether and Zinc -oxide eugenol paste with carriers were the next most accurate recording mediums.Recording waxes were consistently unreliable.Distortion occurred more frequently in a vertical direction followed by an antero-posterior direction.



RECORDING OF OCCLUSAL RELATIONSHIPIt may vary from simple apposition of the apposing casts by occluding sufficient remaining natural teeth to recording of jaw relationship in the same manner as for a completely edentulous patient.



The horizontal jaw relation (planned intercuspal position or centric relation) in which restoration is to be fabricated should be determined during diagnosis & treatment planning.

Mouth preparation should be based on this determination including occlusal adjustment of natural dentition wherever indicated.



METHODS OF RECORDING OCCLUSIONDirect apposition of casts.Interocclusal records with posterior teeth remaining.Occlusal relation using occlusal rims on record bases.Jaw relation made entirely on occlusion rims.Establishing occlusion by recording of occlusal pathways.www.indiandentalacademy.com


DIRECT APPOSITION OF CASTSAlso known as HAND ARTICULATION coined by KROGH POULSEN. www.indiandentalacademy.com


INDICATIONSSufficient opposing teeth that remain in contact to make the existing jaw relationship obvious.

Only few teeth are to be replaced on short denture bases.

There is no evidence of occlusal pathology.



The opposing casts are occluded by hand.

It can be moved slightly in various lateral anteroposterior direction of movement by observation of facets on remaining teeth.



The occluding casts are secured together either with wooden sticks/wire nails & sticky wax .

They are mounted in a articulator.



ADVANTAGES:Though there are limitation, yet it is better than using an inaccurate record between the remaining natural teeth.It eliminates the clinical appointment for establishing occlusal relationship.



LIMITATIONSThe principle danger is this method may perpetuate the existing vertical dimension and any existing occlusal disharmony.So occlusal analysis and correction of any occlusal disharmony should precede the accepting of such a jaw relation.



INTEROCCLUSAL RECORDS WITH POSTERIOR TEETH REMAININGINDICATION: It is the modification of the first method and is used when sufficient teeth remain to support the partial denture (Kennedy class III or class IV) but the relationship of opposing teeth does not permit the occluding of cast by hand.www.indiandentalacademy.com


PROCEDUREA uniformly softened, metal reinforced wafer of base plate or set up wax is placed between the teeth and the patient is guided to close in centric relation.



All excess wax should be removed with a sharp knife.



The wax is removed and chilled thoroughly. It is again replaced in mouth to correct the distortion and chilled again.



The wax record should be further corrected with a bite registration paste to obtain a more accurate and dimensionally stable record.For this procedure the opposing surface of teeth is coated with petroleum jelly for ease of removal of record.



The impression paste is applied to both the side of the wax record and the patient is assisted to close in centric relation guided by the wax record.



After the paste is set, the record is removed and excess is trimmed off.



Record is secured to the maxillary cast and then mounted in an articulator.



ADVANTAGESProvides an accurate interocclusal record.

If an intact opposing arch is present stone can be directly poured into the record to serve as a opposing cast.

Acceptable procedure in fabricating unilateral fixed partial denture.



OCCLUSAL RELATIONALSHIPS USING OCCLUSAL RIMS ON RECORD BASESINDICATION: When tooth supported edentulous space is long.

When opposing teeth do not meet.



When one or more distal extension areas are present.



PROCEDUREAccurate records bases are to be used to support the occlusal relationship.



Occlusal rims are constructed over the record bases by wax occlusion rims or modeling plastic occlusion rims.



Vertical dimension is corrected . Occlusion rims are reduced in height just out of occlusal contact. A single stop is added to maintain their terminal position.



Bite registration is made by injecting the recording medium in between the two occluding surfaces.



Patient should be guided to the centric position and should be held in position till the material sets.



Completed record is examined and it is trimmed so that only cusp tips and indices remain. Cast are then mounted on the articulator by using the record.



JAW RELATION RECORDS MADE ENTIRELY ON OCCLUSAL RIMSWhen no occlusal contact exists between the teeth, such as when opposing maxillary complete denture is to be made concurrently with a mandibular partial denture.



When few remaining teeth do not occlude and will not influence eccentric jaw movement.

When only anterior teeth is present



OBJECTIVESStatic relation of the maxillary and mandibular casts to each other should be established in three planes. This is accomplished clinically by establishing the vertical ,centric and orientation relationship.



Dynamic relationship of the two cast to be established by protrusive and lateral interocclusal records. These records can be used to program the articulator to simulate the natural movements of the jaw.



PROCEDUREStable record bases and rims are required.Vertical dimension at rest and at occlusion is established by means of NISWONGERs precepts.Centric relationship can be established by direct interocclusal method or by stylus tracing is used.



Eccentric records such as protrusive and lateral records are made.Facebow transfer is made and the casts are mounted on a semi adjustable articulator.Articulator is programmed to simulate natural movements of the lower jaw. Desired occlusion is obtained.



ADVANTAGESMethod of choice when edentulous areas are to be restored are opposed by edentulous areas in a opposing jaw.Better method when the prosthesis is opposed by a completely edentulous arch.Occlusion can be developed rather simply for a typical partial denture, in a minimum amount of time.



Does not require patient co-operation as that needed for generating functional pathway.



LIMITATIONSkill and care is necessary to obtain the intraoral records, accuracy and thoroughness with which they are used to program the instrument.



ESTABLISHING OCCLUSION BY RECORDING OF OCCLUSAL PATHWAYSFUNCTIONALLY GENERATED PATH METHOD.

It is a dynamic record of movement of opposing tooth surface.



Theory:

when the pathways each tooth opposed to the edentulous space makes throughout all functional movements of the mandible are recorded, the artificial teeth may thus be positioned and formed so that it will remain in harmonious contact with its antagonist all the times.www.indiandentalacademy.com


CLINICAL PROCEDUREStable acrylic resin record base with compound hard wax or hard inlay wax (purple) can be used to record the occlusal pathways.



Occlusal rims is constructed slightly higher than the occlusal plane so that the natural teeth are apart by 0.5 to 0.75mm.



Buccolingual width of rim is several millimeters wider than that of opposing teeth. This is necessary to record the full range of motion.



There are two methods of having the patient grind the occlusal pathways.

First method : the patient is instructed to wear the occlusal rims continuously for 24 hrs excepting when eating and drinking hot or chilled drinks.

He should be told to close the jaws intermittently and grind the wax in all possible jaw position. www.indiandentalacademy.com


The patient is asked to wear the prosthesis overnight so that any involuntary or bruxism contacts can be records.

The resulting pathway will be record of all possible jaw movements and tooth contacts.



Second method: is for the patient to create the pathway directly under the supervision of the dentist.

Advantage: dentist is able to observe and correct the movement the patient is making.

Disadvantage: atleast 30min of active movement of the mandible is necessary.



The wax pattern is boxed and poured in improved stone to provide permanent record of the generated pathways.



The stone record is mounted on a articulator and the artificial teeth are set to contact the record.



ARTIFICIAL TEETH SET TO THE GENERATED PATHWAYThe incisal pin is opened 1mm before the artificial teeth are positioned. This increase in vertical dimension will be returned to normal by selective grinding of the teeth.The selective grinding develops occlusal anatomy of the denture teeth to conform to the functionally generated stone path.



After the teeth are set in correct alignment the incisal pin is returned to correct vertical dimension of occlusion.Prussian blue dye is painted on to the surface of generated pathway. Opening and closing tapping movements are made of stone path against the denture teeth.



Spots of dye are transferred to the denture teeth. selective grinding is done till the incisal tip touches the incisal table.

The articulator is not moved into protrusive and lateral movements because these positions are incorporated in the pathway.



ADVANTAGESThe method makes unnecessary the registration of inter occlusal records or a face bow transfer and dispenses with the need for a complicated articulator.Jaw movements and tooth pathways are reproduced under more nearly functional conditions than is the case when static registration are transferred to an instrument.



LIMITATIONSNot indicated when the opposing occlusion is provided by a complete denture or when all the teeth is not present in the opposing occlusion.Resistance may be encountered by the mandible as the teeth shear through the wax, which may serve to deflect the mandible from its natural path.



The patients masticatory force and direction may vary with foods of different types. So the masticatory pattern of the teeth during actual function differs from that which they follow as they generate pathways.Cannot be used to replace the anterior teeth.



ESTABLISHING JAW RELATIONS FOR A MANDIBULAR PARTIAL DENTURE OPPOSING A MAXILLARY COMPLETE DENTURE



It is the most common situation.

The maxillary denture may be already present or it may be made concurrently with the opposing partial denture.



ESTABISHMENT OF JAW RELATION WITH EXISTING MAXILLARY COMPLETE DENTUREIf the existing maxillary denture is satisfactory and has acceptable occlusal plane, it can be treated as natural dentition. Face bow transfer is made and the cast obtained from the denture impression is mounted on the articulator. centric and eccentric records are made.



The stylus must be carefully removed from the denture and attached to the same palatal location on the stone cast.Mandibular cast is orientated by means of centric records.After processing the partial denture is mounted against the complete denture for occlusal correction. It will ensure more accurate cuspal relationship.



When the mandibular partial denture replaces all posterior teeth and the anterior teeth are noninterfering, a central bearing point tracer may be mounted in the palate of maxillary denture and centric relation recorded by means of an intraoral stylus tracing against a stable mandibular base.



If the relationship of maxillary posterior teeth to the mandibular ridge is favorable and the complete denture is stable functionally generated method can be used to obtain the records.If the maxillary denture has be made with occlusal plane too low and improper interarch relationship due to any malposition of the natural teeth and if those teeth has been lost ,repositioning of the maxillary posterior teeth should be done before the construction of the partial denture.



MAXILLARY DENTURE TO BE MADE CONCURRENTLY WITH THE PARTIAL DENTUREIf the mandibular partial denture will be tooth supported it should be restored first and so the maxillary complete denture is made to occlude with an intact arch.



If the mandibular partial denture has one or more distal extension bases, the occlusion on both the arches should be accomplished simultaneously.

All mouth preparations and restorative procedures need should be accomplished on remaining natural teeth.



Occlusion should be established with favorable tooth-to-ridge relationship, optimal occlusal plane and cuspal harmony between all occluding teeth.After try-in both dentures can be processed at the same time or the maxillary denture alone is fabricated and a record is obtained using functionally generated pathway and mandibular partial denture teeth can be set to accommodate the record. This gives good occlusal harmony.



FIXED PARTIAL DENTURE AGAINST REMOVABLE PARTIAL DENTURE In this situation fixed partial denture should be fabricated and then the construction of removable partial denture should be made.



Better occlusion is possible if the occlusal plane is restored with the abutment restorations and pontics for the fixed prosthesis and the teeth of removable partial denture are then arranged to articulate with them.



REFERENCESRemovable partial denture-McCrackens.Clinical removable partial prosthodontics-StewartPartial dentures OsborneRemovable partial prosthodontics-Grosso & Miller.Partial dentures -SwensonOcclusion in removable partial denture-JPD, Jan-2004Accurate occlusal relationship in partial denture construction-JPD,Nov 1953.Clinical evaluation of the accuracy of interocclusal recording materials-JPD ,Feb 1984



Occlusal Registration in Removable Partial Denture / orthodontic courses by Indian dental academy

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