28.laboratory remount

28. Laboratory Remount28. Laboratory Remount

John Beumer III, DDS, MSJohn Beumer III, DDS, MSDivision of Advanced Division of Advanced

Prosthodontics, Biomaterials and Prosthodontics, Biomaterials and Hospital DentistryHospital Dentistry

UCLA School of DentistryUCLA School of Dentistry

This program of instruction is protected by copyright ©. No portion of This program of instruction is protected by copyright ©. No portion of this program of instruction may be reproduced, recorded or transferred this program of instruction may be reproduced, recorded or transferred by any means electronic, digital, photographic, mechanical etc., or by by any means electronic, digital, photographic, mechanical etc., or by any information storage or retrieval system, without prior permission.any information storage or retrieval system, without prior permission.


Purpose:Purpose:2. To correct errors in occlusion that

have occurred during processing3. To return dentures to the correct

vertical dimension of occlusion4. To restore centric and bilateral

balanced occlusion


Purpose:Purpose:2. To correct errors in occlusion that

have occurred during processing3. To return dentures to the correct

vertical dimension of occlusion4. To restore centric and bilateral

balanced occlusion

Laboratory RemountLaboratory Remount

Processed dentures intact on master castsProcessed dentures intact on master casts Articulator and plaster mountingsArticulator and plaster mountings Straight handpiece and acrylic burrsStraight handpiece and acrylic burrs Quick setting plasterQuick setting plaster Plaster bowl and spatulaPlaster bowl and spatula Articulating paperArticulating paper Wax spatulaWax spatula

Instruments and MaterialsInstruments and Materials

The processed dentures are removed from the flasks.The processed dentures are removed from the flasks.

Lab remount – Lingualized OcclusionLab remount – Lingualized Occlusion

Lab Remount – Lingualized OcclusionLab Remount – Lingualized Occlusion

Carefully inspect the plaster mountings and the Carefully inspect the plaster mountings and the underside of the casts. Remove any stone underside of the casts. Remove any stone particles or debris before joining the two together particles or debris before joining the two together

Place each cast on its plaster mounting and check that it Place each cast on its plaster mounting and check that it goes to place exactly. If the casts do not seat on the goes to place exactly. If the casts do not seat on the mountings properly look for particles of plaster which may be mountings properly look for particles of plaster which may be adhering to the mounting or the cast. adhering to the mounting or the cast.



While performing the lab remount and equilibration procedure, the master cast with the polymerized denture must be effectively secured to the articulator mountings. Begin by placing notches in both the mounting and the master cast with an acrylic burr.


Soak the cast and mountings in water for 5 minutes and add a plaster paddy on each side as shown.


• Begin by locking the centric latches Begin by locking the centric latches and make sure the pin is set at zero.and make sure the pin is set at zero.

• Check the amount of pin opening that has Check the amount of pin opening that has occurred secondary to processing. In this occurred secondary to processing. In this case there was less than .1 mm of opening.case there was less than .1 mm of opening.

Zero Zero settingsetting


Inspection reveals only minimal tooth movement. The pin opening following processing was less than .1 mm.


Begin equilibrating in centric Begin equilibrating in centric with the centric latches locked. with the centric latches locked. Tap the two members of the Tap the two members of the articulator together with articulator together with articulating paper interposed articulating paper interposed between. between.

The objective is to restore the vertical dimension of occlusion to the level achieved with the trial denture and develop as many occlusal contacts as possible in centric.


Upon initial closure missing centric contacts were noted in association with the first molars on the left and the second molars on the right. Note the occlusal contact on the buccal incline of the mesial buccal cusp of the left maxillary 2nd molar. This contact should be eliminated.


These contacts were restored with selective grinding. All of the grinding in this case was directed towards the central fossae of the mandibular posterior teeth.


Following adjustment to restore centric and the VDO, some contacts on the buccal inclines of the upper posterior teeth may be noted (arrows). These should be removed. Only the lingual cusp tips of the maxillary posterior teeth should be in contact in centric.


When you have finished equilibrating in centric there should be no contact associated with the buccal cusps of either the mandibular or the maxillary teeth, and the incisal guide pin should contact the incisal guide table.


With the incisal guide pin at zero and in contact with the incisal guide With the incisal guide pin at zero and in contact with the incisal guide table, the vertical dimension of occlusion has been restored.table, the vertical dimension of occlusion has been restored.


When the VDO has been restored, the denture is examined in working, balancing and protrusive.


Equilibrate in working, balancing and protrusive.

WorkingWorking

In working excursion, the maxillary lingual cusps contact the buccal inclines of the mandibular lingual cusps but the maxillary buccal cusps are not in contact.



WorkingWorking

Note the working contacts (ovals).

BucccalBucccalsideside

LingualLingualsideside



WorkingWorking

Note the balancing contacts (ovals).

BucccalBucccalsideside

LingualLingualsideside


BalancingBalancing

In balancing, the maxillary lingual cusps contact the lingual inclines of the mandibular cusps. When the exercise is completed there should be simultaneous contacts on both the working and balancing side during function.


ProtrusiveProtrusive

Develop protrusive contacts as shown. Light contact of the anterior teeth in protrusion enhances stability. Note the contacts in the 2nd molar region.

The processed dentures are The processed dentures are removed from the flasks and secured to the removed from the flasks and secured to the mountings as shown previously.mountings as shown previously.

We are now ready to begin theWe are now ready to begin thelaboratory remount procedure.laboratory remount procedure.The purpose of the laboratoryThe purpose of the laboratoryremount is to adjust the occlusionremount is to adjust the occlusionto account for distortions thatto account for distortions thatoccur during processing.occur during processing.

Laboratory Remount – Monoplane OcclusionLaboratory Remount – Monoplane Occlusion

Neutrocentric concept



All of the teeth, with the exception of the laterals and the cuspids (because of esthetic considerations) should be on the same plane and there should be no vertical overlap of the anterior teeth.



Close examination reveals that there has been some Close examination reveals that there has been some movement of the denture teeth during processingmovement of the denture teeth during processing. Not Not all the teeth are on the plane of occlusionall the teeth are on the plane of occlusion.



With a piece of fine sand paper and a flat glass slab, sand the denture teeth so With a piece of fine sand paper and a flat glass slab, sand the denture teeth so that both the buccal and lingual surfaces of the posterior teeth and the incisal that both the buccal and lingual surfaces of the posterior teeth and the incisal edges of the central incisors touch the occlusal plane. In this setup note that the edges of the central incisors touch the occlusal plane. In this setup note that the cuspids and the laterals are slightly above the plane for esthetic purposes.cuspids and the laterals are slightly above the plane for esthetic purposes.



After this step all of the cusp tips of the posterior teeth, plus the incisal surfaces of the central incisors are on the same plane.


Neutrocentric concept Attach the maxillary cast and mounting to Attach the maxillary cast and mounting to the articulator. Make sure the incisal guide the articulator. Make sure the incisal guide pin is set at zero. Lock the condyles. Close pin is set at zero. Lock the condyles. Close the articulator and note how much vertical the articulator and note how much vertical opening has occurred as a result of opening has occurred as a result of processing.processing.

Insert strips of articulating Insert strips of articulating paper between the teeth and paper between the teeth and lightly tap them together in lightly tap them together in centric occlusion. Premature centric occlusion. Premature contacts will usually show up contacts will usually show up as dark areas with a light as dark areas with a light center.center.



When restoring the vertical dimension of occlusion of When restoring the vertical dimension of occlusion of dentures made with nonanatomic teeth make your dentures made with nonanatomic teeth make your adjustments on the mandibular arch only. The heaviest adjustments on the mandibular arch only. The heaviest premature contacts show up as dark areas with light centers premature contacts show up as dark areas with light centers (arrow). Grind on these areas first.(arrow). Grind on these areas first.

Restore the Vertical Dimension of OcclusionRestore the Vertical Dimension of Occlusion

•Flatten the occlusal plane of the mandibular arch without disturbing centric Flatten the occlusal plane of the mandibular arch without disturbing centric contacts so that the flat occlusal surfaces of the mandibular arch contact the contacts so that the flat occlusal surfaces of the mandibular arch contact the flat surfaces of the maxillary arch.flat surfaces of the maxillary arch.

Continue with this Continue with this procedure until the incisal procedure until the incisal guide pin comes in guide pin comes in contact with the incisal contact with the incisal guide table. You have guide table. You have now restored the vertical now restored the vertical dimension of occlusion.dimension of occlusion.



Neutrocentric concept When the exercise is completed, all of the teeth, with the exception of the maxillary laterals and perhaps the cuspids (because of esthetic considerations) will be on the same plane and there will be no vertical overlap of the anterior teeth.

Lab Remount – Monoplane OcclusionLab Remount – Monoplane Occlusion

Bilateral balance with balancing rampsBilateral balance with balancing ramps

With a piece of fine sand paper and a flat glass slab, sand the occlusal surfaces of With a piece of fine sand paper and a flat glass slab, sand the occlusal surfaces of only the posterior teeth so that both the buccal and lingual surfaces of the posterior only the posterior teeth so that both the buccal and lingual surfaces of the posterior teeth touch the occlusal plane. Note that the anterior teeth are not touched. To do teeth touch the occlusal plane. Note that the anterior teeth are not touched. To do so would eliminate the vertical overlap and this must be maintained in order to so would eliminate the vertical overlap and this must be maintained in order to develop bilateral balance with the balancing ramps.develop bilateral balance with the balancing ramps.



When you are finished with this step, all the posterior teeth should be on the same plane.


Bilateral balance with balancing rampsAttach the casts and mountings to the Attach the casts and mountings to the articulator. Make sure the incisal guide articulator. Make sure the incisal guide pin is set at zero. Lock the condyles. pin is set at zero. Lock the condyles. Close the articulator and note how much Close the articulator and note how much vertical opening has occurred as a result vertical opening has occurred as a result of processing. In this case there is of processing. In this case there is almost no pin opening.almost no pin opening.

Insert strips of articulating Insert strips of articulating paper between the teeth and paper between the teeth and lightly tap them together in lightly tap them together in centric occlusion. Premature centric occlusion. Premature contacts will usually show up contacts will usually show up as dark areas with a light as dark areas with a light center.center.



Equilibrate in centric first, as shown previously.


Bilateral balance with balancing rampsBilateral balance with balancing rampsEquilibrate in excursionsEquilibrate in excursions

• Next, tract the articulator through working, balancing Next, tract the articulator through working, balancing and protrusive. This is the working position.and protrusive. This is the working position.

In the posterior region In the posterior region premature contacts will may be premature contacts will may be seen on the lingual cusps of seen on the lingual cusps of the mandibular teeth. These the mandibular teeth. These contacts must be removed.contacts must be removed.

• Begin by inserting the appropriate protrusive insert. Begin by inserting the appropriate protrusive insert. Loosen the condylar locksLoosen the condylar locks.



Upon completion the articulator should slide easily from working to Upon completion the articulator should slide easily from working to balancing to protrusive and back. There should be no bumps along balancing to protrusive and back. There should be no bumps along the road. If the contacts on the balancing ramps are insufficient they the road. If the contacts on the balancing ramps are insufficient they may be supplemented with autopolymerizing acrylic resin.may be supplemented with autopolymerizing acrylic resin.

BalancingBalancing

A successful result creates a tripod during excursions and A successful result creates a tripod during excursions and should result in maximum stabilization of the denture bases.should result in maximum stabilization of the denture bases.

ProtrusiveProtrusive WorkingWorking

Lab Remount –Anatomic OcclusionLab Remount –Anatomic Occlusion


When the exercise is completed contacts will be seen on the anterior teeth and the balancing ramps in lateral excursion.

Errors in Centric Occlusion and Their CorrectionErrors in Centric Occlusion and Their Correctiona) Pairs of opposing teeth too long , holding remaining teeth out of occlusion.

Solution: Fossae of the teeth in question are deepened . The cusp tips should not be shortened.

b) The cusp tips of opposing teeth appear to be nearly tip to tip. Solution: Grind on the inclines so as to move the upper cusp inclines buccally and the lower cusp inclines lingually. In so doing the central fossae are made broader, the lingual cusp of the upper teeth narrowed, and the buccal cusp of the lower teeth are also narrowed. The cusp tips should not be shortened.

c) Upper teeth too buccal in relation to the lower. Solution: Broaden the central fossae, and the buccal cusps of the lower teeth are moved buccally by broadening the central fossae. The cusp tips should not be shortened.


Lab Remount – Anatomic OcclusionLab Remount – Anatomic Occlusion

Restore the vertical Restore the vertical dimension of occlusiondimension of occlusion.

With an acrylic burr and a slow speed handpiece remove With an acrylic burr and a slow speed handpiece remove the occlusal prematurities until the pin is closed against the occlusal prematurities until the pin is closed against the incisal guide table(arrow). In this case their was almost the incisal guide table(arrow). In this case their was almost no pin opening. no pin opening.

Equilibrating in centricEquilibrating in centric

Initially most prematurities are found in the posterior region. Initially most prematurities are found in the posterior region. Confine your Confine your initial reductions to cusp inclines, central fossae and marginal ridgesinitial reductions to cusp inclines, central fossae and marginal ridges. Avoid . Avoid the upper lingual and lower buccal cusp tips unless absolutely required in the upper lingual and lower buccal cusp tips unless absolutely required in order to reduce the incisal pin opening to zero.order to reduce the incisal pin opening to zero.


Equilibrating in centricEquilibrating in centric

Centric contacts are now appearing on most posterior teeth. If the Centric contacts are now appearing on most posterior teeth. If the incisal guide pin is still open, you may need to grind on the cusp tips in incisal guide pin is still open, you may need to grind on the cusp tips in order to order to restore the vertical dimension of occlusionrestore the vertical dimension of occlusion to the level to the level determined ideal for the patient during the trial denture appointment.determined ideal for the patient during the trial denture appointment.


Equilibration in CentricEquilibration in Centric

Equilibration in centric is completed. The inicisal pin is at zero and in contact with the incisal guide table. The vertical dimension has been restored.

We are now ready to begin We are now ready to begin equilibrating in working, equilibrating in working, balancing and protrusive. balancing and protrusive. The first step is verify that The first step is verify that the appropriate protrusive the appropriate protrusive inserts have been placed.inserts have been placed.

•Select and position the appropriate protrusive insert.Select and position the appropriate protrusive insert.

Excursions


MostMost occlusal discrepancies found during occlusal discrepancies found during “working“working”” and and “balancing”“balancing” can be corrected can be corrected by reducing premature contacts on the by reducing premature contacts on the buccal cuspsbuccal cusps of the maxillary teeth and the of the maxillary teeth and the lingual cuspslingual cusps of the mandibular posterior of the mandibular posterior teeth teeth (non-centric holding cusps)(non-centric holding cusps) otherwise otherwise known as the rule of BULL (buccals of the known as the rule of BULL (buccals of the uppers and linguals of the lowers).uppers and linguals of the lowers).


Equilibration in working

a)a) Begin by the equilibrating the Begin by the equilibrating the right working sideright working side. . Slide the articulator through right working with Slide the articulator through right working with articulating paper between the denture teeth. Begin articulating paper between the denture teeth. Begin grinding by removing any contacts that are present grinding by removing any contacts that are present on the on the inclines inclines of the of the lower right lingual cusps as lower right lingual cusps as shown in the diagram (arrows).shown in the diagram (arrows).


b) b) Check the contacts on the buccal inclines Check the contacts on the buccal inclines of the upper buccal cusps. During working, of the upper buccal cusps. During working, they should all be about equal. If not, make they should all be about equal. If not, make the appropriate adjustmentsthe appropriate adjustments

In this case In this case working working contacts on contacts on the 2the 2ndnd molar molar are too light are too light (red arrow).(red arrow).

Working positionWorking position

Equilibration in working

Remount –Anatomic OcclusionRemount –Anatomic Occlusion

c)c) Slide the articulator through working Slide the articulator through working again and observe the contacts on the again and observe the contacts on the balancing side, balancing side, the lingual inclines of the lingual inclines of the lower buccal cuspsthe lower buccal cusps. Premature . Premature balancing side contacts are reduced by balancing side contacts are reduced by grinding on the lingual inclines of the grinding on the lingual inclines of the lower buccal cusps. If there are no lower buccal cusps. If there are no balancing side contacts, the balancing side contacts, the working working side contactsside contacts should be reduced until should be reduced until balancing side contacts appearbalancing side contacts appear.. Continue until working and balancing Continue until working and balancing contacts are about equal.contacts are about equal.

d)d) Repeat the same sequence on the opposite sideRepeat the same sequence on the opposite side

Equilibration in balancing

Equilibration in ProtrusiveEquilibration in Protrusive

Equilibrate in protrusive. This may Equilibrate in protrusive. This may require grinding of the require grinding of the anterior teeth as anterior teeth as shownshown and selective reduction of the and selective reduction of the buccal inclines of the posterior teeth.buccal inclines of the posterior teeth.

Protrusive positionProtrusive position

Lab Remount – Anatomic Occlusion Lab Remount – Anatomic Occlusion

Upon completion the articulator should slide easily from Upon completion the articulator should slide easily from working to balancing to protrusive and back. There should be working to balancing to protrusive and back. There should be no bumps along the road. no bumps along the road.

BalancingBalancingProtrusiveProtrusive WorkingWorking

Technology

28.laboratory remount