Assessment of the Dentition and Treatment Options for the Replacement of Missing Teeth

8/3/2019 Assessment of the Dentition and Treatment Options for the Replacement of Missing Teeth

1/9

PRACTICEdental implants

BRITISH DENTAL JOURNAL, VOLUME 187, NO. 5, SEPTEMBER 11 1999 247

Assessment of the dentitionand treatment options for the

replacement of missing teethRichard Palmer,1 and Leslie Howe,2The restorative dentist has a wide range ofoptions for replacement of teeth lost throughdental disease, trauma or causes such as devel-opmental anomalies.

The most common causes of tooth loss aredental caries (and its sequelae) and periodontaldisease. Both diseases have an impact on thecondition and prognosis of the remaining teeth

which will therefore require very careful assess-ment to determine whether they require reme-dial treatment and furthermore whether theywould provide suitable abutments for fixed orremovable prostheses. It is essential that allcaries, endodontic lesions and periodontal dis-ease have been treated before embarking ondefinitive replacement of missing teeth bywhatever method is finally chosen.

Initial examination and considerationsThe minimal clinical examination should assessthe restorative status of the teeth, a periodontal

screening, mucous membranes, TMJs, jaw rela-tionship and occlusion. Vitality testing shouldalso be carried out where appropriate and acomplete periodontal examination for all thosewhose screening indicates significant periodon-titis (BPE score 4 in any sextant) (fig. 1).

The most convenient overall radiographicexamination is the dental panoramic tomo-gram (fig. 2). This may need to be supple-mented with intra-oral radiographs where the

image quality does not permit proper assess-

ment. Bitewing radiographs are adequate fordentitions minimally affected by caries or earlyperiodontitis (fig. 3). Periapical radiographsusing a paralleling technique should be consid-ered advisable for all potential abutment teeth,heavily restored teeth, teeth with known or sus-pected endodontic problems and teeth withmoderate to advanced periodontitis (fig. 4).

Following a full clinical and radiographicexamination, it may be helpful to assign a prog-nosis to individual teeth , taking into account allfactors: restorative, endodontic, periodontal.The prognosis may be simply categorised eg

excellent/good, fair, questionable/poor, hope-less. In addition, the individual tooth prognosismay be affected by the type of planned restora-tion. For example, a tooth with a post crown

1Professor of Implant Dentistry andPeriodontology, Guy's Kings and StThomas' Medical and Dental School,London SE1 9RT2Consultant inRestorative Dentistry, Guy's and StThomas' Hospital Trust, and Specialist

in Restorative Dentistry andProsthodontics, 21 Wimpole Street,London W1M 7AD British Dental Journal1999; 187: 247255

In most cases the

patient and dentist

have a number of

choices for the

replacement of missing

teeth. The advantages

and disadvantages ofthese options can be

presented following

careful clinical and

radiographic

examinations.

3

Fig. 1 Probing to assess the periodontal status ofthe patient. In this case a relatively healthylooking gingival margin has a probing depth ofnearly 10 mm

Fig. 2 The dental panoramic tomogram is avery useful screening tool. This individual hasa heavily restored dentition and moderate toadvanced periodontitis. The image in themid-line is not quite so clear but it does indicateadvanced bone loss on the incisor teeth

Fig. 3 Bitewing radiographs are useful fordiagnosis of caries and early periodontaldisease. Recurrent caries is visible on the mesialaspect of the lower second molar but theinterdental bone crests are at a normal level

In this part, we willdiscuss: Initial examination and

considerations Potential abutment teeth The edentulous area Advantages and

disadvantages oftreatment options

Treatment choices


2/9

248 BRITISH DENTAL JOURNAL, VOLUME 187, NO. 5, SEPTEMBER 11 1999


may have a fair prognosis if it is to be kept as afree standing unit, but would be severely com-promised if used to support a denture or fixedbridge. Features which adversely affect the prog-

nosis are described in Table 1 and illustrated infigure 5.

The basic questions to be asked about indi-vidual teeth are:1. Can the tooth be restored successfully?2. Can the tooth be endodontically treated suc-

cessfully?3. Can the tooth be treated periodontally?4. Following treatment will the tooth be a suit-

able abutment?5. How important is the tooth strategically?6. What impact will the loss of the tooth have on

the overall plan?

The individual tooth assessment and prog-nosis then needs to be put into the context ofthe treatment requirements of the entire denti-tion. In addition to the above considerations,many subjects are seen with missing teeth dueto trauma or developmental absence of teeth inwhom the remaining dentition is very healthy.The potential abutment teeth, the size and loca-

tion of the edentulous space and the occlusalrelationships will have a great effect on the pos-sible restorative solutions.

Potential abutment teethThe size and shape of the natural crown androot form are important considerations.

Fig. 4a This periapicalradiograph shows an upperright central incisor with aninadequate root filling, an

apical radiolucency and a veryshort post. This tooth wouldnot be considered to be asuitable bridge abutment

Fig. 4b The clinical status of the patientillustrated in figure 4a. The missing upper leftcentral incisor space is large. The patient had amid-line diastema prior to tooth loss

Important factors which adversely affect individual tooth prognosisTable 1

Restorations and caries Extensions subgingivally or onto root surfaces

Extension within the pulp chamber or root canalMinimal remaining coronal tooth substanceInadequate or overextended posts in root filled teeth

Endodontic factors Periapical symptoms/signsInability to control the coronal sealInadequate previous RCT including broken instruments in root canalSclerosed canalsFractures/splits

Periodontal factors Probing depths over 6 mmAttachment loss over 6 mmBone loss, more than 50%Poor root morphology especially short rootsInvolvement of furcations especially grade II/IIIMobility especially grade III

Occlusal factorsSigns of parafunction or severe attritionHistory of repeated tooth restoration/fractures

Fig. 5a The upper anterior teeth in this patientare very broken down. They were bridgeabutments which have suffered from caries andfracture. Restoration of these teeth would be

very difficult. If individual restorations werepossible it is unlikely that they would beconsidered to be adequate bridge abutments

Fig. 5b The first and second molars are heavilyrestored. The second molar requires areplacement restoration but this extendssubgingivally to a considerable extent. Thisretromolar area is difficult to performperiodontal surgery to expose restorationmargins


3/9



Teeth with short and conical crown formsoffer poor retention and support. Proceduressuch as periodontal surgical crown lengthen-ing or adhesive restorations may overcomemany of the difficulties (figs 6 and 7). Certainteeth, particularly canines, are very difficultto replace with routine restorations because

of the lack of suitable adjacent abutments(fig. 8). Loss of the canine in a distal free endsaddle situation leaves only the lateral incisoras a distal abutment for a removable prosthe-

sis. This is a most unsatisfactory situationand often leads to progressive loss of theincisors (fig. 9).

Healthy unrestored teeth make the best abut-ments for fixed bridges but the damage thatoccurs to teeth following preparation must beconsidered. Conversely heavily restored teethmay be unsuitable abutments. Further toothpreparation may remove the only remaining

Fig. 5c These heavily worn teeth have beencrown lengthened but restoration is stilldifficult. The lower right central incisor isnon-vital and has a labial sinus. This tooth wasconsidered to be untreatable

Fig. 5d This shows surgical exposure of acomplex bone defect affecting the upper rightfirst pre-molar. A deep periodontal pocket wasdetected on the mesial aspect in relation to thegroove and the bifurcation of this tooth.Recurrent abscesses have destroyed most of thebuccal and mesial bone. This tooth has a verypoor prognosis

Fig. 6a This patient had orthodontic treatmentto close space following loss of an upper centralincisor. The upper right lateral incisor is now inthe position of the central incisor. The gingivalmargins are at different levels

Fig. 6b Minor crown lengthening surgery hasbeen performed on both upper lateral incisorsto improve the aesthetics and allow restorationof the upper right lateral to match that of theupper left central incisor

Fig. 7b A Maryland bridgeused to replace the upper firstand second pre-molars. Seatrests have been prepared toprevent apical displacementand the casting wraps around

the palatal aspects of theabutment teeth

Fig. 7a A palatal view of a Maryland bridgereplacing maxillary incisor teeth. The castingcovers as much of the palatal enamel aspossible to improve the retention, but care hasto be taken to avoid interference with theincisal guidance

Fig. 8. A missing upper canine and lateralincisor. The lateral incisor was developmentallyabsent and a transplantation of the canine intothe space failed. Restoration of this space isextremely difficult


4/9



tooth substance and restorations retained bypins or posts are prone to failure.

The edentulous areaThe requirements for restoring an edentulousarea depend upon its location and size. Many

subjects will accept or prefer non-replacementof missing molars. The concept of the short-ened arch is well established and most patientswill accept a dentition extending from firstmolar to first molar or from second premolar tosecond premolar. Patients with fewer teeth thanthis often have an aesthetic problem and func-

tional disadvantage. The point at whichreplacement of missing posterior teeth in thefree end saddle situation is carried out is verymuch dependent upon patient wishes. Thealternative to an implant supported prosthesisis a removable prosthesis or a limited extensiondistal cantilever bridge. Replacement of molarteeth to prevent over-eruption of teeth in theopposing arch, which may compromise futurerestorative options, is important in some sub-

jects (fig. 10).Few patients will accept non-replacement of

missing incisors/canines. The full range of

prosthetic options can be considered and anexplanation of their advantages and disadvan-tages given to the patient. There are, however, afew general considerations.

Single missing teeth

The size of the edentulous space of single miss-ing units varies enormously. At one extremethere is barely enough space for the missingunit (fig. 11). Orthodontic realignment mayneed to be considered to either eliminate thespace or provide enough to accommodate themissing unit (fig. 12). In other cases the single

Fig. 9 A patient who has suffered fromextensive periodontal disease. The missingupper teeth have been replaced with aremovable partial denture. The lower rightcanine has a poor prognosis and this is themost distal tooth in the lower right quadrant.Loss of this tooth will present considerabledifficulties with provision of a removablerestoration, and the prognosis of the lower

incisors will be affected

Fig. 10. Severe overeruption of an upper firstmolar into the opposing edentulous space

Fig. 11 Following loss of the upper left centralincisor there has been considerable spaceclosure and simple provision of a replacementtooth with normal dimensions is not possible

Fig. 12a This individual has a number of

developmentally absent teeth, spacing betweenthe incisors and rotation of the upper rightpremolar

Fig. 12b Improvement of the spacing androtations following orthodontic treatment


5/9



tooth space may be larger than the naturaltooth. In spaced dentitions the prostheticoptions for replacement of the single missingtooth are more limited (fig. 13).

Multiple missing teeth

In many cases patients will present with anexisting prosthesis which gives informationabout the aesthetic requirements, including the

number and size of teeth which can be accom-modated. In other cases it will be necessary tocarry out a diagnostic wax-up or provision of atemporary denture to establish this. The heightand shape of the edentulous ridge is anotherimportant consideration. It should be remem-bered that following tooth loss, alveolar resorp-tion may occur in both a horizontal and verticalplane (fig. 14). Factors which influence thedegree of resorption include previous peri-odontal and endodontic infections, surgicaltrauma during extraction, postoperative infec-tion, and the type and quality of the previous

prosthesis. Loss of ridge height and width maynecessitate prosthetic replacement of the miss-ing soft and hard tissues to provide adequateaesthetics at the gingival margin and lip sup-

port. In removable prostheses this can beachieved with a labial flange but if a fixedrestoration is to be chosen, then some form ofridge augmentation may be necessary. The pro-

Fig. 13a Replacement of the upper left centralincisor with a removable denture

Fig. 13b Palatal view of the same individualshowing extensive coverage of the palataltissue by the chrome cobalt framework.Replacement of an incisor in a spaced dentitionmay be achieved using a removable denture, a

spring cantilevered bridge or a single toothimplant

Fig. 14a An anterior edentulous space with lossof ridge height in the mid-line. Replacement ofthe missing tissue would be necessary toachieve a satisfactory aesthetic result. This maybe achieved using surgical reconstruction or aspart of the prosthesis

Fig. 14b The same ridge seen from the occlusalaspect showing a concavity on the patients leftside following loss of the buccal plate when thetooth was avulsed

Fig. 15a Loss of the central incisors in thispatient has led to minimal ridge resorption

Fig. 15b The same patient with a provisionalacrylic denture with ridge lapped teeth showing

very good aesthetics


6/9



vision of a diagnostic temporary denture maybe advisable to determine whether a labialflange is needed (fig. 15).

Occlusal relationshipsExamination of the occlusion should encom-pass basic jaw relationships and determina-

tion of the intercuspal position. The patientsmandible should be manipulated into itsmost retruded position and the presence ofany contacts in this retruded arc should besought. Movement of the mandible laterallyand anteriorly should demonstrate the exist-ing occlusal relationships and presence of anysignificant interferences. For individuals withedentulous spans greater than one unit it isadvisable to take accurate study casts andmount these in a semi-adjustable articulatorusing a facebow. This will allow a clear assess-ment of the occlusal scheme and implications

of the treatment alternatives to be more accu-rately assessed.

Some cases, such as Class 2 division 2 incisorrelationships, can pose particularly difficultproblems with any type of prosthesis due tospace and angulation limitation (Figure 16).Tilted and overerupted teeth may need to becorrected before a satisfactory restoration canbe provided. Restoration of individuals withparafunctional activities or severe occlusal weardemand special care.

Advantages and disadvantages of

treatment options

Removeable prostheses

These are a commonly prescribed treatmentoption and may be used as a long term restora-tion or provisional restoration prior to a fixedprosthesis (fig. 17).

Advantages Replace multiple teeth in multiple sites Support obtained from mucosa and/or teeth Generally do not require extensive prepara-

tion of abutment teeth

May be designed to accommodate futuretooth loss

Can be used to replace missing soft tissue Can provide good lip support by incorporat-

ing labial flanges Aesthetics may be very good The least expensive of restorations

Disadvantages Removeable prostheses may not be liked by

patient and may reduce self-confidence Connectors cover soft tissue such as the

palate and gingiva

In subjects with less than ideal oral hygienethey may compromise the health of the peri-odontal tissues and promote caries aroundabutment teeth

Fig. 16a A severe Class II division 2 incisorrelationship with the upper teeth biting into theopposing ridge

Fig. 16b The opposing ridge which hasindentations from the upper incisors

Fig. 17 The replacement of this patients upperincisor teeth with a removable prosthesisproduces an entirely satisfactory aestheticresult. The intra-oral views of this denture areshown in figure 22b

Fig. 18 An adhesive bridge replacing the upperright central and upper left lateral incisors in apatient who has undergone periodontaltreatment. This restoration produces a verygood aesthetic result, although some greying ofthe incisor tips of the abutment teeth is visible


7/9



Retentive elements such as clasps may spoilaesthetics

Moderate maintenance requirements anddurability.

Fixed prostheses

Fixed prostheses fall into two main categories

1.Resin bonded bridgework (fig. 18)2.Conventional partial or full coverage bridge-work (fig. 19)

Resin bonded bridgework

Advantages Minimal or no preparation required Fixed restoration Good aesthetics if ideal spacing exists and

abutment teeth are satisfactory Less expensive than conventional bridges Consequences of failure are relatively small -

caries is readily diagnosed in most instances.Cantilever designs for single tooth replace-ments minimise potential problems

Disadvantages Lack of predictability: decementation leading

to loss of retention or caries under one of theretainers average life span 5 to 7 years.

Dependent upon meticulous technique andavailable enamel surface area for bonding

Change in colour/translucency of abutmentteeth due to presence of retainer

May interfere with occlusion, particularly

incisal guidance Patients may feel sense of insecurity with

restoration, especially if their bridge hasdebonded previously

Conventional partial or full coverage

bridgework

Advantages Fixed Good appearance, including that of abut-

ment teeth if they need to be improved/harmonised

Medium term predictability is good for shortspan bridges

Good control of occlusion possible Minimally compromise oral hygiene

Disadvantages Involve considerable tooth preparation

which sometimes result in pulpal sequelae Failure due to decementation and caries of

abutment teeth may lead to further toothloss

Moderately expensive Highly operator dependent requiring exact-

ing techniques both clinically and technically Requires lengthy clinical time and temporary

restorations Irreversible

Implant retained prosthesesAn implant retained restoration is shown infigure 20.

Advantages Fixed or removeable Independent of natural teeth can provide

fixed restoration where no abutment

teeth exist Immune to dental caries High level of predictability Good maintenance of supporting bone

Fig. 19 A full arch fixed bridge in a patient whohad lost many of her upper teeth throughperiodontitis. This design of bridge is aneffective splint for the remaining teeth whichhave very much reduced periodontal support.The lower right central incisor has beenreplaced with an adhesive bridge

Fig. 20b A palatal view of the same bridge. The

composite restorations on the palatal aspect ofthe 2/1 cover the retaining screws to theunderlying implant abutments

Fig. 20a The anterior view of an implantretained bridge replacing the upper right lateralincisor and both central incisors


8/9



Disadvantages Dependent upon presence of adequate bone

quantity and quality Involves surgical procedure(s) Highly operator/ technique dependent High initial expense and lengthy treatment

time

Moderate maintenance requirements espe-cially for removeable or extensive fixed pros-theses

Treatment choicesIn situations where all types of prosthesis arepossible the final choice may rest with thepatient, and is largely dependent upon theirexpectations/desires, financial budget andwillingness to undergo treatment. It is impor-tant that the patients expectations are realisticand achievable. However, some factors may

dictate that a certain type of restoration is notfeasible or is undesirable. This can best be illus-trated by considering a number of case studies(see Case A to Case C).

ConclusionThe patient should be presented with the

treatment alternatives and an indication oftheir respective advantages and disadvantagesin their particular case. The treatment plansshould be outlined in writing and an estimateof the relative costs given. Complex treatmentplans require more detailed descriptions anda projected timetable for completion andcostings. It is important to ensure that thepatient understands the proposals and isgiven the opportunity to clarify any matters.A written consent to the agreed treatmentplan is advisable.

Fig. 21a This young individual has missingupper lateral incisors. Orthodontic treatmenthas provided only enough space for very smallreplacement teeth

Fig. 21b The same patient is wearing aremovable partial denture

Case AFigure 21 shows a young female(aged 17 years) who has develop-mentally missing lateral incisors.While the removable prosthesis(Fig. 21b) provides reasonableappearance and function, it isunderstandable that a fixed alterna-tive is desired by the patient. Thespace available for replacement ofthe missing teeth is narrow (about

4mm), thereby preventing place-ment of an implant, even if a nar-row version is used. The patient hasalready undergone extensive ortho-dontic treatment and is unwillingto undergo more to create sufficientspace. The adjacent abutment teethare perfectly healthy and extensivepreparation to provide a conven-tional bridge is contraindicated.Therefore the only fixed restorationthat is feasible and desirable is aresin bonded bridge.


9/9



Case CFigure 23 shows a patient with asingle missing anterior tooth. Theadjacent teeth are crowned. In situ-ations where the abutment crownshave a good prognosis, a conven-tional bridge would be the obviouschoice. However, if the abutmentteeth are supported by post crowns,they may be considered to have aquestionable prognosis as bridgesupports and an alternative

replacement should be consideredsuch as a single tooth implant.

Case BFigure 22 illustrates a young female(aged 35 years) who lost four ante-rior teeth in an accident. The eden-tulous span is wide and the

abutment teeth not ideal. The eden-tulous ridge form is good and alabial flange is not required for aes-thetics or lip support. The presentremoveable prosthesis (fig. 22b)provides good aesthetics with a nat-ural looking spaced dentition. Sherequests a fixed prosthesis. A diag-nostic set up which eliminates thediastemas by increasing the numberof prosthetic teeth is shown in fig.22c). This setup would be requiredfor a conventional fixed bridge but

was unacceptable to the patient asshe wanted to maintain the appear-ance of a spaced dentition. Shetherefore has two choices aremoveable prosthesis or four indi-vidual single tooth implants.

Figure 22a A large anterior endentulous spacefollowing traumatic loss of teeth

Fig. 23 A patient with a single missing upperincisor tooth. The adjacent teeth are crowned

and have a good prognosis. Replacement of themissing tooth with a conventional bridge wouldbe straightforward

Fig. 22b The patient wearing a removablepartial denture bearing four teeth with spacesbetween them

Fig. 22c The same patient with a diagnosticset-up placing five teeth in the gap and nospaces

Documents

Assessment of the Dentition and Treatment Options for the Replacement of Missing Teeth