What features should be considered in the extraoral examination

Three important features should be assessed in the extra-oral examination: the gape, the functional 'aesthetic zone' and the jaw relationship. Evidence of limitation in the gape is a clear warning that passage of instruments or insertion of the prosthesis through the lips or between opposing teeth will inhibit treatment (see Figs 3.8 and 3.15).

The morphology and function of the lips have a profound effect on the display of the dental arch and alveolus. Assessment is required when the patient is relaxed and while the history is being recorded, so that the extent of display of the oral tissues is evident during speaking, smiling and laughing.

In the edentulous patient, or those with one edentulous jaw, it will be apparent if the extent of resorption requires a flange to maintain the correct position of the arch and the facial profile. A short upper lip is likely to create a high smile line that reveals both the artificial teeth and flange (Fig. 4.3). Standard transmucosal abutments would be an inappropriate choice. This evidence may support the choice of a removable overdenture rather than a fixed prosthesis.

Assessment of the partially dentate patient is even more crucial since the length of the artificial tooth crowns, and the lack of gingival tissue either in the edentulous span or around the adjacent teeth, are likely to affect the design and display of the prosthesis.

Abnormal length, angulation and position of the artificial teeth, and the presence of dark spaces between the prosthesis and the natural teeth and gingivae, should be anticipated. Such an evident defect of tissue requires consideration to be given to ridge augmentation.

Abnormalities of the lips arising from previous surgical intervention and trauma may make access to

Fig. 4.3 A difficulty foreseen at examination is that the patient has a 'high smile line'. A flange is necessary to provide artificial teeth of acceptable length of crown and to mask the abutments.

the jaw difficult, and result in distortion of the space available for the prosthesis. Patients who have undergone treatment for cleft lip and palate, or who have had resection of the mandible with reconstruction using nasolabial flaps for example, require detailed evaluation.

Obvious disproportion and malalignment of the jaws, present in skeletal Class II and III situations, and patients presenting with 'long or short face' patterns may create problems in the design of the prosthesis. There is the potential risk of unfavourable cantilever-ing and loading or inadequate space for components (Figs 4.4, 4.5).

What intra-oral aspects of the overall examination of partially dentate jaws are peculiar to implant treatment?

The clinical examination should be directed to gaining specific evidence. In the previous chapter general aspects have been considered and emphasis has been placed on selecting those patients with a well-restored stable occlusion and a high standard of plaque control associated with non-progressive periodontal disease.

The anticipated relationship between the arch restored by the prosthesis and the ridge will indicate potential key features in the design of the prosthesis. These are the likely extent of cantilevering between the occlusal surfaces and the implants, and any divergence between the angulations of the artificial crowns and the implants. The extent of the loss of alveolar bone will influence the potential length of these crowns. The width of the bounded span, which

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Fig. 4.4 One problem posed by restoring a Class II division ii malocclusion is that the crowns are angulated on the implant bodies, seen in the lateral skull radiograph.

Fig. 4.4 One problem posed by restoring a Class II division ii malocclusion is that the crowns are angulated on the implant bodies, seen in the lateral skull radiograph.

Fig. 4.5 An obviously unfavourable ¡aw relation makes implant treatment very difficult for this edentulous patient.

Fig. 4.6 One feature of the single-tooth span is unfavourable: the replacement crown will be potentially wider than the adjacent central incisor tooth.

will accommodate artificial teeth of an appropriately matched shape, must be noted (Fig. 4.6).

The initial inspection may give an early indication of the number of implants that may be suitably accommodated in the span, and whether or not there

Fig. 4.10 Traumatic tooth loss in a patient with a Class III malocclusion has resulted in an unfavourable relation between the residual anterior maxilla and the natural mandibular incisor teeth.

Fig. 4.11 A possible solution with the arch supported by a flange can be judged with a trial insertion.

Fig. 4.9 Clinical examination shows the anterior ridge is narrow and the vertical incisor relation is unfavourable, inhibiting the choice of implants.

Fig. 4.7 The long free-end span of the edentulous area of the maxilla is appropriate for restoration with dental implants.

Fig. 4.8 Natural teeth adjacent to the spaces in the lateral incisor areas are unfavourably inclined.

Fig. 4.9 Clinical examination shows the anterior ridge is narrow and the vertical incisor relation is unfavourable, inhibiting the choice of implants.

is tilting of the adjacent natural teeth which may influence their positions (Figs 4.7, 4.8).

Examination of the opposing arches in the inter-cuspal contact position will indicate the extent of the vertical space between the opposing arch and ridge. A deep vertical overlap of the natural anterior teeth, typically associated with a Class II division ii malocclusion, will suggest that a potential problem may exist in accommodating implant abutments (Fig. 4.9).

Fig. 4.10 Traumatic tooth loss in a patient with a Class III malocclusion has resulted in an unfavourable relation between the residual anterior maxilla and the natural mandibular incisor teeth.

Fig. 4.11 A possible solution with the arch supported by a flange can be judged with a trial insertion.

Conversely, excessive vertical separation may identify problems of restoration of the occlusion, typically associated with a Class III jaw relation (Figs 4.10,4.11).

What intra-oral aspects of the examination of the edentulous jaw(s) of the patient are significant to implant treatment?

Careful oral examination and assessment of the patient's existing complete dentures will indicate if shortcomings in the design of the prostheses have created problems affecting their performance. In such circumstances routine dental treatment may be a possible solution.

In the edentulous situation one denture, usually the upper, may be considered satisfactory by the patient who seeks a solution to problems with the other. Inspection may suggest some obvious changes that could overcome these problems. However, if a fixed prosthesis in one jaw offers a possible solution, the effect upon a hitherto satisfactory removable opposing prosthesis should be considered. Where there is jaw atrophy, will changes in the base and occlusion of the conventional denture be sufficient to create the desired

Fig. 4.13 A flat anterior edentulous ridge has been successfully restored with implants stabilizing a fixed prosthesis.

Fig. 4.12 The occlusal table is appropriately restored with an overdenture opposing a natural arch.

Fig. 4.13 A flat anterior edentulous ridge has been successfully restored with implants stabilizing a fixed prosthesis.

solution? If both dentures are poorly designed, have worn teeth or a poor fit then the examination may indicate that new conventional dentures are desirable before implant treatment is considered.

Where one jaw is partially dentate, or the arch is intact, very careful consideration must be given to the presence of irregularities in the natural arch and occlusal table created by tilting or overeruption of the teeth. Lack of balance with the opposing prosthesis produced by eccentric interferences may readily destabilize it. Further investigation using articulated study casts will reveal any lack of space for the prosthesis or implant components. The anticipated length of the occlusal table will influence the choice of a fixed cantilever or removable overdenture (Fig. 4.12).

Inspection and palpation of the jaw and ridge produce an immediate impression of the volume of available bone potentially available for implant insertion. The mandible may have a flat or inverted oral contour, but palpation may indicate an adequate volume of bone in the anterior part sufficient to accept implants as short as 7 mm or as long as 20 mm (Figs 4.13, 4.14). However, palpation may indicate a narrow ridge crest, and in the posterior area significant lack of height above the mental foramen, indicative of an unsuitable volume of bone for implantation.

Evidence of a well-formed maxillary ridge should include assessment of possible labial concavities, which may dictate the angulation of the future implants. In the presence of advanced resorption doubt concerning the appropriate treatment plan can only be resolved with supporting radiographic evidence. Palpation will obviously indicate where substantial fibrous replacement of the bone has already occurred (Box 4.4).

What evidence should be gathered about the soft tissues enveloping the dental arch or covering the edentulous ridges?

Both the thickness and position of the mucoperios-teum must be assessed. Part of this examination will

Fig. 4.14 A lateral skull radiograph showing a flat mandibular surface with a good depth of bone for implantation.

Box 4.4 Important local features

• Is the residual dentition healthy?

• Is there adequate gape for instrumentation?

• Does sufficient inter-tooth space allow positioning of fixture(s), obutment(s) and prosthesis?

• Does inter-arch space permit restoration?

• Is the occlusion stable, without evidence of excessive tooth surface loss?

• Is there overeruption of opponent teeth?

• How many sites require restoration?

• Are the gingivae evident ('e g. high lip line')?

• Will the prosthesis replace coronal or corona I/alveolar tissue?

include appraisal of the extent to which the restored arch will be displayed on speaking and smiling. The so-called 'aesthetic zone', which is assessed during oral examination, therefore involves the dental and alveolar tissues including those to be restored by the implant prosthesis. Those patients who only display the occlusal third of the arch below the 'smile line' (high lip line) are sometimes more willing to accept a compromise in the resulting appearance, but this should not be a forgone conclusion, and possible

Fig. 4.15 A reduction in the alveolar width following healing of the socket has resulted in palatal positioning of the implant. The cast shows that the crown secured on the abutment is likely to be extensively ridge lapped.

Fig. 4.17 The resulting 'gingival line' is associated with a good profile for the single-tooth crown emerging from the mucosal cuff.

Fig. 4.18 A 'black triangle' is evident between the single-tooth crown on 12 and the adjacent central incisor tooth due to a deficient papilla.

Fig. 4.16 Favourable soft-tissue contours exist adjacent to and around the natural teeth that abut a single-tooth span.

Fig. 4.18 A 'black triangle' is evident between the single-tooth crown on 12 and the adjacent central incisor tooth due to a deficient papilla.

shortcomings should be explained with the aid of a 'diagnostic wax-up/trial denture' before a treatment plan is finally agreed. For example, the design of a crown for a single tooth restoration will be influenced by the position of the head of the implant body. Hence, previous resorption of the alveolus may result in a longer clinical crown than those of the adjacent natural teeth, unless grafting of the alveolus and soft-tissue surgery can recapture the original form of the tissues. Evidence of labial resorption will suggest that an implant is likely to be positioned more palatally, with the prospect of the crown being ridge lapped and formed with a more bulky emergence profile (Fig. 4.15).

Visual inspection and periodontal probing of natural teeth adjacent to an edentulous span will confirm if the crevices are healthy and of normal depth. Also it will be evident if the gingivae have a normal architecture or exhibit recession. Surgical planning will aim to maintain the position of the gingival margins and not alter the form of the papillae around the tooth (Figs 4.16-4.18). Prosthetic planning will consider the likely height of the artificial crown, access for cleaning and the required position of the implant in any fixed design.

When examining the mandible it is important to consider the position of the ridge crest and determine whether well-keratinized masticatory mucosa is likely to surround the future position of a transmucosal abutment (Fig. 4.13). When resorption is advanced, the prosthetic space is often narrow, with mobile mucosa lying close to the centre of the anterior aspect of the body of the jaw. A partly mobile or completely mobile cuff around the abutment may be accommodated, although allowance must be made for the varying sulcus depth when constructing the prosthesis. However, misalignment of the implant with the prosthetic space can have important consequences. These can include complaints of impairment of tongue movement, difficulties with speech, abutment hygiene and recurring soreness as a result of inflammation of the cuff. It is therefore crucial to record an accurate impression of the prosthetic space, especially when removable overdentures are planned.

'Ridge mapping' may be employed to determine the thickness of the mucoperiosteum overlying the jaw (Fig. 4.19). This would subsequently form a cuff around the abutment, and will influence the choice of transmucosal abutment. The technique is described in Chapter 5. Similar information can be obtained from a

Extraoral Examination
Fig. 4.19 Ridge mapping also assesses the available width in the alveolar process.

CT scan where a radio-opaque marker has been placed on the mucosal surface.

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