Prosthodontic treatment of patients with hypodontia

CONNECTIVE

TISSUE

OF EDENTULOUS

relationship of ridges without activity cannot be discerned.

RIDGE

dentures to periosteal

CONCLUSION It is probable that during the healing process after extraction of teeth the thickness of the ridge connective tissue is decreased while the density is increased unrelated to the wearing of dentures. In this study no other conclusions can be reached. REFERENCES 1. 8stlund, S. G.: The effect of complete dentures on the gum tissues. Acta Odontol Scant1 16~1, 1958.

2.

Nedelman, C. I., and Bernick, S.: The significance of age changes in human alveolar mucosa and bone. J PROSTHET DENT 39~495, 1978. 3. Turck, D.: A histologic comparison of the edentulous denture and non-denture bearing tissues. J PROSTHETDENT 15~419, 1965. 4. Krajicek, D. D., Dooner, J., and Porter, K.: Observations on the histologic features of the human edentulous ridge. Part I: Mucosal epithelium. J PROSTHETDENT 52:526, 1984.

Reprint requests to: DR. DAYTON D. KRAJICEK 2951 S.W. WANAMAKER DR., STE. A TOPEKA, KS 66614

Prosthodontic treatment of patients with hypodontia R. B. Winstanley, University

of Sheffield,

M.D.S., F.D.S.R.C.S.(Ed)* School of Clinical

Dentistry,

Sheffield, England

ypodontia or partial anodontia is the congenital absence of one or more teeth. The inconvenience to patients will vary depending on the specific teeth and the number of teeth that are missing. Usually deciduous teeth are not absent, and they are often retained into the third or fourth decade if no permanent successors develop. The problem posed to the dentist by patients with a number of missing teeth was discussed by Hobkirk and 13rook.l Patients with hypodontia frequently have malformation of the teeth that are present. The teeth are usually small, conical, and taper toward the occlusal or incisal surfaces (Fig. 1). If no permanent successors have developed, deciduous teeth may be retained and may show marked attrition. Lack of alveolar growth may be associated with this condition and result in an increased freeway space (interocclusal distance). Such patients frequently show a marked mandibular protrusion when they attempt to approximate their teeth (Fig. 2). Other patients with hypodontia exhibit a deep overbite (vertical overlap) (Fig. 3). Treatment of the condition is necessary to improve appearance, m.astication, and speech. The appearance is depressing to patients because of malformed teeth, spaces due to missing teeth, and overclosure on mastication. Depending on the age of the individual, appearance may cause severe psychologic disturbances.

Removable partial dentukes

*Senior Lecturer in Restorative Dentistry.

These may be successful to approximate teeth and eliminate small spaces, particularly after orthodontic treatment. However, the anatomy of the natural teeth is

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Fig. 1. Teeth typical of hypodontia patients. Various forms of prosthodontic treatment are available, depending on the severity of the condition.

Complete dentures This form of treatment should be reserved for patients for whom other forms of treatment have failed, or in whom teeth are grossly carious or have poor periodontal support. Satisfactory results can be achieved with complete dentures, but they may place an excessive load on already poorly developed denture-bearing tissues.

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Fig. 2. sure.

A, Mandibular

Fig. 3. Hypodontia of anterior

rest position.

patient

with

B, Mandibular

deep vertical

clo-

overlap

teeth.

usually unfavorable for conventional clasp design because of lack of suitable teeth and tooth undercuts (Fig. 4). In addition, clasping may be unslightly anteriorly. The construction of crowns to aid in the support and retention of a removable partial denture may give excellent results, but frequently the anatomy of the teeth precludes such preparations. Acid etch composites may be used to provide undercuts on tapered teeth, which can then be clasped,2 and may also be used to improve esthetics of the anterior teeth.3

688

the

Fig. 4. A, Lack of maxillary teeth and poor undercuts on remaining teeth cause problems for removable partial dentures. B, Removable partial denture in place. C, Occlusion, appearance, and increased face height with upper and lower removable partial dentures in place. (Compare with Fig. 3.)

Fixed partial and attachment dentures Where the teeth present are of relatively normal anatomy and are well supported, this form of treatment can give excellent results for the replacement of a number of missing teeth. Great care should be taken in younger patients when preparations are undertaken because of the large size of the pulp chamber. UnfortuNOVEMBER

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nately, many patients with hypodontia also have small, tapering, conical teeth that are not conducive to retentive crown preparations. The use of parallel pin castings will aid retention, but in younger patients it will be hazardous to the pulp. Endodontic therapy followed by post and core build up on teeth with poor crown morphology allows great scope for esthetic and functional fixed or removable partial dentures, provided there is adequate root length. This is an extensive undert.aking in young patients and should be reserved for later in life. Acid etch composite retained fixed partial dentures of the type first described by Rochette4 or later modifications with plastic or wax patterns for cast metalwork show considerable promise as restorations to replace small spans of missing teeth where abutments exhibit unsuitable crown contours for conventional fixed partial dentures (Fig. 5). Little if any tooth preparation is necessary for such restorations provided there is room for them without interferring with the opposing dentition. Some of the problems of the resin-to-metal-framework bond associate’d with fixed partial dentures have been reduced by elimination of the perforations and use of electrolytically etched metalwork. This latter modification offers the potential for restoration of the dentition in patients with hypodontia.5

Fig. 5. A, Missing lower anterior teeth in patient with hypodontia restored with acid etch fixed partial denture. 8, Lingual view of fixed partial denture in A.

Overdentures Partial or complete overdentures or a combination of the two provide a straightforward form of treatment for patients with hypodontia.6 They give the esthetic result of complete or partial dentures while the remaining natural teeth are used to provide additional support. They can be particularly useful in the young patient since little if any tooth preparation is necessary, and yet they provide a dramatic improvement in esthetics at a time when psychologic disturbance may be severe. Where fixed restorations are planned in later life, complete or partial overdentures can provide acceptable intermediate restorations. The contour of the teeth in many patients with hypodontia is such that undercuts are not present. Blocking out, which can lead to gingival hyperplasia and false pocketing, is therefore unnecessary. All the teeth in each arch will often be found to provide a common path of insertion for an overdenture with adequate retention. The large amount of interocclusal distance allows placement of artificial teeth in the most satisfactory position without restrictions because of a lack of available room. The immediate improvement in esthetics, both in the resting position and on mandibular closure, is dramatic to the patient (Fig. 6). Obviously the largest drawback to this technique is the full coverage of teeth that support the overdenture, which may predispose to caries, periodontal proble:ms, or direct trauma to the soft tissues. THE JOURNAL

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Patient selection, motivation, maintenance of oral hygiene, and follow-up is absolutely essential. Hobkirk and Brook’ list the indications for overdentures as (1) patients with very few teeth, (2) teeth with small conical crowns or short roots, (3) small dental arches with little lip support, and (4) large spaces between the teeth that are difficult to correct orthodontitally.

Other methods Orthodontic treatment can be invaluable to help correct malocclusion in patients with hypodontia. It can eliminate small spacesby bringing teeth together to form groups that can provide support and retention for fixed or removable partial dentures. In patients with reduced partial anodontia, orthodontic treatment can close the spaces of missing upper lateral incisors by approximating the canines to the central incisors or increasing the spaces so that a prosthesis can be provided.’ In severe situations, especially with an excessive interocclusal distance, surgical repositioning of the dental arches may provide an alternative to overdentures, and one that is a more satisfactory form of treatment.

DISCUSSION Many different or combined methods of treatment are available for the patient with partial anodontia. Varia689

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Fig. 6. A, Casts showing relative lack of undercuts complete upper and partial lower overdenture. B, Removable partial lower overdenture. D, Mandibular 2, A.) E, Mandibular closure. (Compare with Fig. overdentures. H and I, Closure with overdentures.

tions in the severity of this condition call for careful treatment planning to provide the most satisfactory result for each patient. However, in many situations the use of overdentures can provide an effective and rewarding result for a young patient while later more extensive treatment is planned. They also allow observation of the patient’s motivation and dental hygiene before future treatment is carried out. Whether complete or partial overdentures are provided for a particular patient depends on a number of 690

and single path of insertion for Complete upper overdenture. C, rest position. (Compare with Fig. 2, B.) F and G, Closure without

factors. Usually the upper anterior teeth are the most cosmetically displeasing and will therefore be covered by the overdenture. Often all the upper teeth will be covered to give a complete upper overdenture. With short clinical crown height of the posterior teeth, a partial upper overdenture that covers only the upper anterior teeth will increase the interocclusal distance, and there will be no occlusion of the posterior teeth. A lower overdenture is not as critical from an esthetic viewpoint. However, where there is a large interocclusal NOVEMBER

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distance, a lower over-denture covering the posterior teeth may be necessary to provide the correct occlusal plane and a satisfactory occlusion. Whatever method of treatment is carried out, it is essential that patients maintain meticulous oral hygiene and motivation so that the few teeth they have can be retained. In no situation is this more important than with overdentures, where neglect can lead to rapid destruction of the crowns by caries or loss of periodontal support. Patient selection is critical; otherwise excellent results may end in disaster. Regular recall visits with scaling, polishing, fluoride application, and consolidation of oral hyg.iene instruction are essential. Patients are instructed to leave overdentures out at night to allow the soft tissues to recover and to thoroughly rinse the dentures and the mouth in water after meals if full oral hygiene is not feasible. Coating the tissue surface of an overdenture with a fluoride gel each day will reduce the tendency of the teeth to decalcify. Some patients find the taste unpleasant, and an alternative is to place a thin coat of a fluoride tooth cream on the tissue surface each day. The esthetic and psychologic improvement in the patient illustrated in Figs. 1) 2, and 6 was so great that it was later decided to extract the deciduous lower incisor and make a complete lower overdenture, because the lower anterior teeth had become the esthetic problem. CONCLUSIONS Restorative treatment for patients with severe hypodontia has been discussed. Partial or full overdentures

combine simple methods with excellent esthetic and functional results. They also afford time to assess the patient with regard to more extensive restorative treatment. Unfortunately, although little or no tooth preparation is carried out when making overdentures, lack of patient cooperation and oral hygiene after placement of the prosthesis can quickly lead to extensive caries and periodontal problems. REFERENCES Hobkirk, J. A. and Brook, A. H.: The management of patients with severe hypodontia. J Oral Rehabil 7:289, 1980. 2. Quinn, D. M.: Artificial undercuts for partial denture clasps. A technique using composite filling materials. Br Dent J 151:192, 1981. 3. Erridge, P. L.: Restoration of the teeth in a case of oligodontia. J Dent 8:132, 1980. 4. Rochette, A. L.: Attachment of a splint to enamel of lower anterior teeth. J PROSTHET DENT 30~418, 1973. 5. Livaditis, G. J., and Thompson V. P.: An improved retentive mechanism for resin-bonded retainers. J PROSTHET DENT 47:52, 1.

1982.

6. 7.

Duthie, N.: Partial anodontia-A prosthetic solution. Br Dent J 150~46, 1981. McNeill, R. W., and Joondeph, D. R.: Congenitally absent maxillary lateral incisors: Treatment planning considerations. Angle Orthod 43:24, 1973.

Reprzn~requeststo: DR. R. B. WINSTANLEY UNIVERSITY OF SHEFFIELD SCHOOL OF CLINICAL CHARLES CLIFFORD DENTAL HOSPITAL WELLESLEY ROAD SHEFFIELD. ENGLAND

DENTISTRY

Palateless dentures: Help for the gagging patient John B. Farmer, D.M.D.,*

and Mark

E. Connelly,

D.D.S.**

Fort Carson, Colo., and University of Alabama, School of Dentistry, Birmingham, Ala.

0

ne of the most exasperating experiences in complete denture prosthodontics is treatment of the gagging patient. A few patients in this category cannot tolerate conventional maxillary dentures that have maximum palatal coverage and extension of all borders. Radical

departure from accepted clinical procedures should be carefully evaluated and used only as a last resort. The purpose of this article is to describe a palateless denture technique for the management of gagging patients. A palateless denture technique has been previously described by Booth.’

The opinions and assertions herein are those of the authors and are not to be construed as official or as reflecting the views of the U.S. Department of the Army or the U.S. Department of Defense. *Colonel, DC, U.S. Army Dentac, Fort Carson, Cola. **Assistant Professor of Clinical Dentistry.

BACKGROUND

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Gagging has been generally classified as either somatogenic or psychogenic.2 As previously summarized by Means and Flenniken3 somatogenic gagging results 691