ACTIVE RESTORATIVE CARE MANAGEMENT OF GENERALIZED TOOTH WEAR

CURRENT CONCEPTS ON THE MANAGEMENT OF TOOTH WEAR:

PART3. MANAGEMENT OF GENERALIZED TOOTH WEAR

DR NADIA KHALILMDS RESIDENTOPERATIVE

Restorative Management Of Patients With Generalized Tooth Wear(Turner & Missirilian)Category 1: excesive wear with loss of OVD

Category2: excessive wear without loss of OVD,but with space available

Category3:excessive wear without loss of OVD,but with limited spaceFor all cases,a set of diagnostic casts mounted in CR strongly advised.A semi adjustable articulator with arbitrary facebow acceptable but a kinematic transverse horizontal axis facebow transfer preferable to plan tentative increase in OVD without introducing errors in horizontal jaw relationship otherwise an alteration in OVD results in loss of accuracy in horizontal relationship leading to faulty restorations.KINEMATIC FACEBOW

To estimate desired increase in OVD, measurement of existing OVD of worn dentition and the face height with the mandible at rest with adequate lip seal:the difference between the two measurements needs to accommodate the desired increase in OVD and the freeway space.

Then the measurement is programmed into articular(by raising the pin on it) & diagnostic framework fabricated accordingly.Initially the transfer of prescribed INCREASE IN OVD should be done by using fully reversible& adjustable materials E.g. Resin composite which will determine:

1. Patients tolerance2. Esthetic acceptance of proposed changes3. Avoiding the propagation of errors which may arise where definitive long term restorations prepared extra orally are placed clinically without any interim restoration.Final wax up should provide:

Simultaneous stable bilateral tooth contactsCR coincident with CODisclusion of post. teeth,upon lateral and protusive mand. movements.Ant teeth disclusion,when post teeth contact in max intercuspation.Shared/even anterior guidanceCanine guided occlusion,with planned group function upon loss of canine guidance with absence of working or non working occlusal interferences.

It is often useful to have a vacuum formed matrix produced from duplicate cast of diagnostic wax up to provide patient with an idea of restorative end point.Alternatively, RESIN composite mock ups may be placed directly to evaluate changes.

Restorative techniques:Adhesive vs ConventionalConventional restorative techniques(which depend on mechanical tooth preparation to provide retention & resistance form) have been the mainstay of treatment for management of tooth surface loss.With improvements in adhesive technology and availibilty of superior resin composite,adhesive retained restorations are becoming increasingly popular.Choice of technique depends on keeping in mind the following factors:Conventional restorations require copious removal of sound dental hard tissue(from tooth structure already compromised by tooth wear).Adhesive, in contrast are minimally invasive.Conventional,full coverage restorations associated with high risk of loss of pulp tissue vitality Conventional preparations irreversible whereas adhesive offer a large element of flexibility as minimal tooth reduction required to accommodate such restoration.The success of adhesive restorations dependent to a large extent on the presence of a copious quantity of high quality tooth enamel. However, in the case of conventional restorations, the process of tooth preparation may lead to the loss of any residual enamel, which will reduce the intrinsic strength of the tooth and compromise the longevity of the restoration.A STUDY BY EDELHOFF & Sorenssen says that 63;72 % of coronal tooth tissue may be removed during prep of all ceramic or PFM crowns.Adhesive techniques are highly operator sensitive and require adequate moisture control.Higher costs associated with conventional restorations.

Conventional offer superior levels of longevity however failures are irreparable as compared to adhesive restorations which can be addressed.

THEREFORE,it is prudent to consider adhesive additive approach while managing a worn dentition as it can act as a medium term restoration which can eventually be replaced by conventional techniques after establishing patients tolerance and adaptibilty to the new occlusal scheme.CATEGORY 1 PATIENTs: EXCESSIVE TOOTH WEAR, TOGETHER WITH A LOSS IN THE OVDMost straight forward to manage as the resultant inter-occlusal clearance created through the process of tooth wear will provide most of required space for the restorative material, without the need for aggressive occlusal reduction (by a planned increase in theOVD),while maintaining a physiological Freeway space(FWS). A full coverage,hard acrylic stabilisation splint,Michigan Splint,can be used to evaluate patients tolerance to planned occlusal changes.A new facebow record &intra occlusal record maybe required.Ideally,half the increase in OVD SHOULD BE INCORPORATED IN EACH ARCH allowing a better distribution of increase in crown to root ratio & makes the increase in OVD less abrupt & improving the chances of successful adaptation.

CLINICAL CASE 1 FIGURE2A 67 year old male,presenting with edentuluos arch in lower right quadrant and wearing lower anterior dentition,with 6 mm FWS.CAUSE of tooth wear:bruxism which has been accentuated in lower ant region by the presence of an abrasive i.e. PFM crowns.Metalloceramic crowns at LL 5,6,7

PROPOSED PLAN:

Restore the worn lower anteriors LL321,LR123 with indirct resin ceromer overlays& to simultaneously increase OVD BY 3mm.1st stage: Elective removal of crowns at LL 5,6,7.Placement of composite onlays & fitting of provisional crowns at LL5,6 & 7 to the new occlusal Vertical height .After adaptation,provisional crowns replaced with metallo ceramic crowns designed to include rest seats ,guide planes &undercuts in acc. to the p.d. design.Restoration provided canine guided occlusion,with even centric stops in CO and posterior disclusion on protrusion & lateral excursion.

If conventional restoration planned,tooth prep of one arch proposed in one single visit.Acrylic or silicone indices formed from diagnostic waxup can be used to asess level of occlusal reduction required.Provisional restorations should be given for 6-8 weeks. To evaluate esthetics & function.Construction of customized anterior guidance table can be used to achieve anterior occlusal scheme.If metallo ceramic crowns prescribed,metal or biscuit try in stages preferred to minimze errors.Final occlusal scheme should give mutually protected occlusion.

CATEGORY 2:EXCESSIVE WEAR WITHOUT LOSS OF OVD,BUT WITH LIMITED SPACE AVAILABLE

Discrepancy between CO &CR.Need arises to plan an increase in OVD.A full coverage,hard acrylic occlusal splint should be given to provide increase in OVD to reqd. range,while mandible is manipulated into its retrusive arc of closure.Should be worn continously for 1 month to evaluate the tolerance in OVD.

CASE 3(FIG 4)A 31 YEAR OLD MALE WITH GENERALISED TW due to combination of bruxism &extrinsic erosion.Discrepancy bw CO & CR, & inadequate intra occlusal clearance to accommodate restorations witout maintaining physiological FWS.TREATMENT PLAN:Michigan splint given to increase OVD by 3.5 mm.After a month,adhesive restorations with minimum prep. given.Posteriors managed by type 3 cast gold adhesive onlays.Anteriors restored by indirect resin ceromer palatal veneers with incisal edge coverage.

CATEGORY 3:NO LOSS OF OVD,WITH INSUFFICIENT SPACE FOR RESTORATIVE MATERIALSMost difficult cases to restore because space is NOT readily available due to tooth repositioning brought about by alveolar compensatory growth.Therefore, every effort should be made to obtain space without increasing the OVD.Only if such methods fail can OVD be increased by programmed modification using occlusal splints.

METHODS OF CREATING SPACE:

1.SURGICAL CROWN LENGTHENING,WITH OSSEOUS RECONTOURING:Increase the quantity of coronal tooth tissue,in teeth with short clinical crown heights,where further occlusal reduction may severely compromise retention & resistance form where conventional restorations are being planned.Restoration margin no more than 0.5 mm subgingivally placed to prevent biological width encroachment.

Drawbacks of crown lengthening:

Unsightly black triangles between teeth .Unfavourable crown to root ratio.Gingival recession often accompanying the healing process,which may result in exposure of subgingival margins.-Therefore, ALLOW adequate healing period before placement of definitive restoration esp. in ant region for avoidance of poor post restorative esthetics & allow the level of gingival crest to stabilize(ideally 6 months). Post op sensitivity especially as the restorative margins will need to be placed upto newly exposed dentine.

2.Elective Endodontics:

Permits the application of a post and core system to further augment the available core material, or in the case of a grossly over-erupted tooth,where there is a need to correct the occlusal plane discrepancy (where occlusal reduction would otherwise result in iatrogenic pulpal exposure).HOWEVER, it might also compromise the long term prognosis of affected tooth if RCT fails.In conditions of tooth wear caused by parafunctional habits like clenching or grinding,post and core restorations give a bleak outlook towards success.3.ORTHODONTIC TOOTH MOVEMENTPermits the intrusion of a grossly over-erupted tooth, where there is a need to correct the occlusal plane discrepancy (where occlusal reduction would otherwise result in iatrogenic pulpal exposure)THANK YOU