PRACTICE tooth surface loss 19 Treatment planning · 552 BRITISH DENTAL JOURNAL, VOLUME 186, NO. 11, JUNE 12 1999 PRACTICE tooth surface loss 1 Treatment planning R. Ibbetson 1 An

552 BRITISH DENTAL JOURNAL, VOLUME 186, NO. 11, JUNE 12 1999

PRACTICEtooth surface loss

1 TreatmentplanningR. Ibbetson1

An effective treatment plan is dependent ongathering information from the history, exami-nation and special tests, such as radiographs andvitality testing, and analysing it to make a diag-nosis. In restorative dentistry diagnoses are fre-quently multiple: successful treatment planningdepends on accurate diagnoses and appropriatedecision-making. The series has emphasised theimportance of effective prevention, it has alsorecognised that restoration may be needed toprotect the remaining tooth structure.

The treatment planThe treatment plan should take the patient anddentist to the point where disease is controlledand the dentition functional and stable.Absolute stability is not achievable: all restora-tive work deteriorates to the point where failurebecomes inevitable. Restorative work cannot beguaranteed for a patient’s lifetime and no out-rageous claims for longevity should be made.

The dentist must be aware of the patient’swishes. Frequently they ask the dentist to selectthe treatment. Rather they should be encour-aged to make decisions for themselves while thedentist’s role is to provide the information. Veryoften the patient’s expectations of treatment aredifferent from our own.1,2

In the worn dentition, it may be difficult todetermine the major aetiological factor. Com-monly, more than one type of wear is present. Itis rare to find a patient with tooth surface losswithout at least some element being caused byacid erosion.3 Management of the patient whoseteeth are worn poses the following questions:1. Does the patient perceive that there is a

problem?2. Is the wear currently active: if so, is it rapid

or slow?3. Will the patient cooperate in a preventive

approach to the management. If so, howeasy will it be to monitor its success?

4. Is the wear so severe that restoration isrequired?

5. If restoration is required, is there sufficientcrown height and do occlusal relationshipsallow reasonable form and stability to beachieved?

6. Are other teeth likely to require restorationin the short to middle term?

The answers determine the strategy for man-agement. They all require decisions and patientinvolvement, particularly with regard to their

possible long-term consequences as was dis-cussed in Part 7 on failures.

The first stage in developing a treatment planis to decide which teeth have a hopelessly poorprognosis, which are sound with a good prog-nosis and finally which teeth require treatmentand why. This may not always be evident imme-diately as some teeth may require investigationto make or confirm a diagnosis, while decisionsregarding periodontally compromised teethmay be influenced by the patient’s efforts inplaque control.

Treatment plan -v- sequence oftreatment Once the treatment plan, the ultimate goal, isknown, the dentist must establish a course thatwill reach it, the sequence of treatment.

Treatment plans should be written down forboth dentists’ and patients’ benefit and thedentist should commit the sequence of treat-ment to paper. This may show illogicalities: ifthese are not identified treatment may becomeunduly complicated or impossible to deliver.For example, it is wise to complete placementof any necessary amalgam restorations beforeproviding the patient with an occlusal splintbecause re-fitting an existing splint over anewly placed restoration is a complication thatis better avoided.

Sequence of treatmentThe treatment can be broken down into asequence of stages. These are:

Stabilisation

Reassessment 1

Preliminary Restorative Phase

Reassessment 2

Definitive Restorative Phase

Reassessment 3

Maintenance

The need for re-assessmentDuring treatment the effects of what has beendone should be periodically reviewed. Thisallows either the dentist or patient to retire

9

1Senior Lecturer in ContinuingEducation, Eastman Dental Institutefor Oral Health Care Sciences,University of London and HonoraryConsultant in Restorative Dentistry,Eastman Dental Hospital, UniversityCollege London Hospitals Trust, 256Gray’s Inn Road, London WC1X 8LD© British Dental Journal 1999; 186: 552–558

Restorative dental careis planned in a seriesof stages. Castsmounted in anarticulator are used asan essential part ofthis process.

The Series Editors are Richard Ibbetsonand Andrew Eder of the Eastman DentalInstitute for Oral Health Care Sciencesand the Eastman Dental Hospital

BRITISH DENTAL JOURNAL, VOLUME 186, NO. 11, JUNE 12 1999 553


honourably from active treatment if that seemsappropriate. For example, the patient’s plaquecontrol may not reach an appropriate standard.This is clearly important in its own right but isalso a useful barometer of a patient’s level ofinterest and commitment. Efficacy of plaquecontrol should be measured by bleeding scoresnot by plaque scores. Plaque scores inform onlyabout performance on the day while bleedingscores give a longer term view.

Sometimes it becomes apparent that thepatient may not wish to continue with treat-ment or the need for the planned work hasdiminished. Organisation of treatment intostages allows convenient points to be reachedwhen the dentition is relatively stable. If thedentist or patient agree, the patient can enter amaintenance programme and be reviewedperiodically. The other phases of treatment areorganised to allow a logical progression towardcompletion of the treatment plan.

Stabilisation phaseThe aims are the resolution of any acute prob-lems and the stabilisation or elimination ofactive disease. Included are:• Relieving pain and discomfort.• Instituting effective plaque control proce-

dures: this may include some initial non-surgical periodontal treatment.

• Eliminating active carious lesions.• Extracting teeth that have a hopeless prognosis.• Any necessary gross occlusal adjustment, for

example a grossly over-erupted tooth.• Replacement of missing teeth. This may be

needed because of appearance or because fewposterior teeth are in occlusion preventingthere being a sufficiently stable position ofclosure. If teeth are replaced early in treat-ment, the prosthesis should generally be pro-visional with the definitive one beingprovided during the final restorative phase.It is prudent to avoid being fully committed

to extensive treatment of a patient too soon.Generally existing crown and bridgeworkshould not be removed early in treatment.Dentists often do this on grounds of its beingill-fitting and wishing to provide better tempo-rary restorations: most temporary coveragedoes not achieve this aim. Once existing workhas been removed there is a commitment tocomplete treatment which a lack of patientcompliance can make difficult.

Re-assessment 1This is a review of whether the patient’s condi-tion has stabilised. Is the patient comfortable,are they are able to accept treatment, whatimprovement has been made in their standardof plaque control? Does the patient appear to beinterested in treatment? It may be that a lack ofresponse or difficulties in accepting treatmentrequire revision of the long-term goals.

Fig. 1 Labial view of anteriorteeth showing chipping ofincisal edges of maxillaryincisors

Fig. 2 Incisal edges ofmaxillary anterior teethdemonstrating acid erosion

Fig. 3 Mounted casts showinginitial contact in the retrudedaxis position

Fig. 4 The ‘condyle’ has movedaway from the rear wall of thecondylar housing by‘translation’ as the casts haveslid into ICP

Fig. 5 Trial adjustment of thecasts to eliminate the slidebetween retruded andintercuspal



Preliminary restorative phaseTreatment is directed toward:• Investigating individual teeth, providing cores

and new plastic restorations as necessary.• Any definitive endodontic treatment.• Non-surgical periodontal therapy. • A full analysis of the occlusion.

The clinical examination of the occlusion issupplemented by an extra-oral analysis usingaccurate study casts made from alginate impres-sions and a facebow transfer so that the maxillarycast can be mounted in an articulator. An inter-occlusal record taken in the retruded axis position(RAP) is needed to relate the mandibular cast tothe maxillary and thereby to the hinge axis of thearticulator. The casts are used to assess in moredetail the extent of the tooth surface loss and todetermine which teeth might benefit from furtherrestoration. Consideration then must be given todetermining exactly what difficulties may compli-cate the proposed restorations.

Re-assessment 2A further review of progress is made and anyconcerns that the dentist or patient has over thefinal phase of treatment can be discussed.

There are a number of aspects to re-assess:• Disease control• The aims of the definitive restorative phase• The position of the teeth• The crown height available• The position of mandibular closure and the

jaw relationships.

Periodontal condition and disease controlThere should be no active disease. Homecareshould be commensurate with supporting thefinal restorative phase of treatment. If there arespecific sites of periodontal concern remainingdespite good plaque control, there may be indi-cations for periodontal surgery. However, thetraditional goal of pocket elimination by surgi-cal means is becoming increasingly hard tosubstantiate.

The definitive restorative phaseThe aims of the final restorative stage should bewell defined. Decisions about whether to pro-vide indirect restorations for patients withworn teeth are based on:• Aesthetics• Occlusal stability• Protection of the remaining tooth structure.

Two sets of study casts should be availablethat are mounted accurately in the articulator.One acts as a baseline record. The second isavailable for rehearsing treatment, for examplecrown lengthening surgery, occlusal adjust-ment or diagnostic waxing.

The position of the teethAssessment of the casts or a diagnostic wax-upmay show that one or more teeth are malposi-

Fig. 6 Intercuspal positionprior to occlusal adjustment

Fig. 7 Intercuspal positionfollowing elimination of theslide from retruded tointercuspal showing a smallincrease in overjet

Fig. 9 Patient with worn andrestored anterior teeth,missing teeth and an unevenocclusal plane. The teeth are intheir intercuspal position

Fig. 10 Buccal view of the teethin occlusion

Fig. 8 Incisal edges of themaxillary incisors restoredwith adhesive compositerestorations



tioned and sometimes orthodontics can behelpful. Orthodontics in the pre-restorativemanagement of the worn dentition is dis-cussed in Part 10 of the series. It needs to beplanned jointly by the restorative dentist andthe orthodontist. It must be establishedwhether permanent retention will be necessarypost-treatment: it is frequently required afterteeth have been moved in adult patients.

Crown heightThe study casts and the wax-up provide a verygood idea of clinical crown height. If the teethare too short, aesthetics, retention and resis-tance form and occlusal stability are all likely tobe compromised. A surgical crown lengtheningprocedure should be considered to increase theheight available. This aspect of treatment willbe described in Part 11. Where teeth have largecores, it is important that the margins of thefinal crowns are placed apical to the margins ofthe cores on sound dentine — 2 mm is consid-ered sufficient.4 Frequently this is impossiblewithout prior crown lengthening.

Creating space for restoring worn teeth bycontrol of the jaw relationshipThere are a number of other ways of creatingspace to allow restoration of short teeth.These are by: • Altering the position of mandibular closure

while maintaining the existing verticaldimension of occlusion

• Increasing the vertical dimension of occlu-sion

• Reversing the changes that have taken placein the position of the teeth as a result of thewear through relative axial tooth movement.Sometimes a combination of more than one

of these approaches is necessary. In allinstances, it is important to determine a stableRAP before planning the definitive restora-tions. This requires a period of wear of anocclusal splint. The details of this appliance canbe found in Part 3 of this series.

Alteration of the position of mandibular closureThis is considered when there is need to restoreteeth in the anterior part of the mouth and therest of the dentition is generally sound. Thechange in the position of mandibular closure iseffected by occlusal adjustment. The aim is tocreate a new intercuspal position (ICP) someway distal to but at the same vertical dimensionas the existing one. The feasibility of doing thisdepends on the nature of the discrepancybetween RAP and ICP: there must be signifi-cant mandibular translation between the twopositions for it to be a possibility.

The magnitude of this type of movement ishard to determine from intra-oral examina-tion. It is seen best on mounted study casts bydetermining the change in the position of the

Fig. 11 The mandibularrelation in the retruded contactposition

Fig. 12 A diagnostic wax-upand set-up in RAP at anincreased occlusal verticaldimension

Fig. 13 A labial view of themaxillary provisionalprosthesis made from a matrixof the diagnostic wax-up

Fig. 14 An anterior view of thefinal anterior restorations

Fig. 15 A middle-aged patientwith a dentition affected bytooth surface loss



articulator ‘condyles’ relative to their condylarhousings when the casts are slid into the inter-cuspal position from the retruded axis position.The only reliable way of determining whetherelimination of the anterior slide would createspace anteriorly is by rehearsing it on the sec-ond set of mounted casts.

Figures 1 to 8 show a 30-year-old female whohad begun to wear the incisal edges of her max-illary central incisors primarily through dietaryerosion such that the incisal edges had begun tochip. Figure 1 shows the edge-to-edge incisalrelationship in ICP. The mandibular incisorsoccluded against the worn incisal edges. Therewas no space available to allow the restorationand protection of these maxillary teeth. Thepatient was found to have a significant horizon-tal component to the slide from retruded intointercuspal (figs 3, 4, 6, 7). Adjustment of theposterior teeth to eliminate the discrepancyproduced a new intercuspal position with themandible positioned further distally increasingthe overjet sufficiently to allow conservativerestoration of the incisal edges of the maxillaryincisors with composite resin ( fig. 8).

Increasing the vertical dimension of occlusionThis is the traditional way of creating space forthe restoration of worn teeth. The decision toincrease the vertical dimension of occlusionbrings with it the obligation to restore a largenumber of teeth to ensure that the teeth in botharches have antagonists on mandibular closure.Treatment is demanding for both operator andpatient with many hours being spent by thepatient in the dental chair: it is only undertakenwhen simpler alternatives are inappropriate.

Increasing the vertical dimension not onlyprovides space for restorations but also givesscope for levelling a disordered occlusal plane.Figures 9 to 15 show a middle-aged man inwhom increasing the vertical dimension ofocclusion created space for restorations while atthe same time producing a level occlusal plane.

Total face height measured in the rest posi-tion has traditionally been thought of as rela-tively constant. However, this is not the case. Ifmandibular rest position were thought of asbeing consistent with minimal jaw muscle activ-ity, electromyographic studies carried out in theearly 1960s by Ramfjord indicated that low lev-els of muscle activity were found over a range ofabout a centimetre in most people.5Clinicalexperience has indicated that moderateincreases in the vertical dimension of occlusionare well tolerated by patients as long as they areaccompanied by a stable position of mandibu-lar closure together with anterior guidance thatprovides separation of the posterior teeth onmandibular movement.6 This view is sup-ported by what little research is available.7

Aesthetic limitations on lengthening theteeth incisally often make an adjunctive surgical

Fig. 16 The same patientfollowing surgical crownlengthening and placement ofmetal-ceramic crowns. Thewide embrasures are evident

Fig. 17 Buccal view of patientwith worn deciduous canine

Fig. 19 Palatal view ofcemented ‘Dahl’ appliance onc321/12c

Fig. 20 Buccal view of patientoccluding on anteriorappliance

Fig. 18 Buccal view of patientwith worn deciduous canine



crown lengthening procedure necessary if theappearance is to be reasonable (fig. 15). Thepotential aesthetic disadvantages are that inmoving the gingival margin apically, it comes torest on a narrower portion of the root. Thismakes the embrasure spaces larger which maybe difficult to disguise using the final restora-tions and so-called ‘black-hole’ disease mayresult (fig. 16).

Deliberate axial tooth movementThe method was originally described by Dahl.8

He used removable bite-planes to intrude wornanterior teeth that he wished to crown withouthaving to restore the posterior dentition. Hisoriginal description was of treating individualsin their sixties. However in the past 20 years, ithas been applied to patients of all ages affectedby tooth wear. Developments, particularly theuse of tooth-borne appliances luted to the teethusing glass ionomer cement, has led toincreased predictability and patient compliance.Such an appliance is shown in the treatment ofsomeone whose retained deciduous maxillarycanines had become very worn and the opposingcanines over-erupted (figs 18 to 23).

Casts mounted in an articulator prior totreatment are used to assess where the teeth willbe after axial movement. It is important thatthere are stable occlusal contacts after treat-ment otherwise the teeth will re-erupt.

The technique is often used to simplify thefull reconstruction of the worn dentition. Anappliance cemented to the maxillary anteriorteeth creates space posteriorly allowing easyaccess for the placement of any necessary cores.Once the axial tooth movement is complete andthe posterior teeth have re-established contact,sufficient space will have been created anteri-orly to allow these teeth to be restored. This isfollowed by the placement of the necessary pos-terior crowns. This approach will be describedmore fully in Part 12 of the series.

Relative axial tooth movement, reversing thechanges that accompany wear, allows simplerrestorative procedures. Figures 24 and 25 showthe occlusal surface of a lower first molar toothin a late teenager. The tooth had been eroded bycarbonated drink and there was no clearanceon closure between it and its antagonist. Thetooth was restored with an adhesive nickel-chrome occlusal casting. This was around 1.5mm thick and after cementation was initiallythe only site of occlusal contact. Two weekslater, axial tooth movement had taken place andall the teeth had intercuspal contacts.

The final restorationsThe aims are to provide optimal aesthetics, rea-sonable function and ensure that any restora-tions placed are compatible with the patientmaintaining themselves in a disease-free state.The previous investigative stages will, in con-

Fig 21 Following axial toothmovement, posterior occlusionre-established

Fig. 22 Following removal ofthe appliance showing thespace available to allowrestoration

Fig. 23 Tooth surface losshaving affected the occlusalsurface of a mandibular molarin a 17 year-old

Fig. 24 Mandibular first molarrestored with adhesive metalcasting cemented at anincreased vertical dimensionof occlusion



junction with the patient’s wishes, have deter-mined which teeth would benefit from restora-tion. Diagnostic waxing forms an essential partof the planning.

Diagnostic waxingRestorative treatment is much more pre-dictable when the outcome can be envisaged(fig. 25). It is also gives the patient an idea of thefinal result and encourages realistic expecta-tions. Specifically diagnostic waxing will:• Allow dentist and patient to see a mock-up of

the final restorations.• Indicate if there is sufficient crown height to

give adequate retention and resistance formin the preparations, reasonable aesthetics andadequate occlusal form.

• Show where occlusal plane discrepancies (forexample, slightly over-erupted antagonistteeth) need correction if a desirable occlusalscheme is to be achieved and optimalaesthetics produced.The wax-up provides a number of addi-

tional advantages. It can guide tooth prepara-tion using it to make matrices that are eitherused to evaluate the preparations or as tem-plates for the temporary coverage. The tempo-

raries have ostensibly the same form as thefinal restorations so they can be used to checkthe appropriateness of the tooth reduction bymeasuring their thickness. The temporarycrowns can also be used to rehearse the finalresult. It is an interesting thought that dentistsare trained as undergraduates to make a wax‘try-in’ for a removable prosthesis. However itseems this is rarely advised for a fixed prosthe-sis or a number of crowns. The temporaryrestorations fulfil that role and the finalcrowns should present few surprises either tothe dentist or the patient.

Re-assessment 3This final review is an evaluation of whether theoriginal aims of treatment have been met andwhether further active restorative care isrequired. If all is satisfactory, the patient entersthe maintenance phase. The details of whichwere described in Part 6 of the series.

This article has described the importance ofdetermining, in conjunction with the patienttheir restorative needs and has outlined anapproach to the delivery of care. The way inwhich teeth wear, together with their inherenteruptive potential, can combine to create par-ticular difficulties in restoration. They oftenpresent broad, flat functional surfaces wheretheir relationships with antagonists make it dif-ficult to create adequate space for effectiverestoration. Various strategies that can be usedto create space for restorative purposes havebeen outlined. The benefits of deliberate axialtooth movement as a conservative method formanagement have been described. Orthodon-tics and surgical crown lengthening can also bevaluable adjuncts to restorative care. The nexttwo articles in the series will discuss in moredetail their use and limitations in the restorativemanagement of worn teeth.

1 Brisman A S. Esthetics: a comparisonof dentists’ and patients’ concepts. JAm Dent Assoc 1980; 100: 345-352.

2 Neumann L M, Christensen C,Cavanaugh C. Dental estheticsatisfaction in adults. J Am Dent Assoc1989; 118: 565 -570.

3 Smith B G N. Some facets of toothwear. Ann R Aust Coll Dent Surg 1991;11: 37-51.

4 Hoag E P, Dwyer T G. A comparativeevaluation of three post and coretechniques. J Prosthet Dent 1982; 47:177-181.

5 Garnick J J, Ramfjord S P. Restposition. J Prosthet Dent 1962; 12:895-911.

6 Ibbetson R J, Setchell D J. Treatmentof the worn dentition 2. Dent Update1989; 17: 300-307.

7 Rivera-Morales W C, Mohl N D.Relationship of occlusal verticaldimension to the health of themasticatory system. J Prosthet Dent1991; 65: 547-553.

8 Dahl B L, Krogstad O, Karlsen K. Analternative treatment in cases withadvanced localised attrition. J OralRehab 1975: 2: 209-214.

Fig. 25 Diagnostic wax-up made at thebeginning of the definitive restorative stage

A fascinating, fun look at lifein the 18th and 19th centuryNavy has opened at the RoyalNaval Museum inPortsmouth. The SailingNavy, a heavily interactivepermanent exhibition, offersintriguing new insights intolife on board a typical 74 gunship of the line. In particular,the Navy diet comes under

close scrutiny as well as theweapons and methods offighting.

A specially made video inThe Sailing Navy shows thatthe food on board was much better than generally thoughtas the Navy had to keep itscrews both fit and healthy.Examples of typical Navy fareinclude salt beef and there arealso ship’s biscuits on display.Methods of attack andweapons are also featured,which is part of FlagshipPortsmouth at the HistoricDockyard.

The Sailing Navy is situatedin Storehouse No II alongside

Horatio Nelson: The Hero AndThe Man, the gallery devotedto Nelson that opened at theend of December and which is already proving highly popular.

The Museum is open dailybetween 10 am and 5 pm.Admission prices are £3.50adults, £3 seniors and £2children. Call the FlagshipPortsmouth Information Line,01705 8615 12 for full detailsof times and prices.

James De Roche, 7,checks to see if he has gotscurvy at the Royal NavalMuseum’s new gallery TheSailing Navy

Documents

PRACTICE tooth surface loss 19 Treatment planning · 552 BRITISH DENTAL JOURNAL, VOLUME 186, NO. 11, JUNE 12 1999 PRACTICE tooth surface loss 1 Treatment planning R. Ibbetson 1 An