An atraumatic denture base design for a tooth-bound mandibular removable partial denture

aumatic denture base design for a tooth-bound ble partial denture

mandibular

E. Grant Eshelman, Jr., DDS, MSa 36th Tactical Fighter Wing Hospital, Bitburg Air Base, Germany Restoration of a tooth-bound posterior edentulous area by removable partial denture is an everyday prosthodontic treatment situation. A foremost patient concern is alternative prosthesis design that can provide a prosthodontic restoration that is both comfortable and hygienic. McCracken’s text1 describes a Kennedy classIII partially edentulous arch as possessing a posterior unilateral edenThe opinions or assertions contained herein are the private views of the author and are not to be construed as official or as reflecting the views of the U.S. Air Force. %oionel, USAF, DC: Chief of Prosthodontics.

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tulous area bounded anteriorly and posteriorly with natural teeth. A Kennedy class III mandibular removable partial denture can be designed as a tooth-borne prosthesis without the need for denture base support from the residual ridges.’ Tissue responds unfavorably to coverage by a removable partial denture if factors of tissue impingement, cleanliness, and pattern of wear are not control1ed.l Avoidance of these problems is effected in fixed partial dentures by use of the, hygienic pontic. This design2avoids contact with the mucosa, prominent muscle attachments, and shallow mucobuccal folds. Adequate space gingival to a pontic allows freedom from mechanical or bacterial sequelae.

Fig, 1. Severely resorbed ridge with highly mobile buccal and lingual alveolar mucosa that extends to ridge crest.

Fig. 3. Setting and wax-up of teeth. Red lines on residual ridge define width of attached gingiva. Blue line approximates the extent of a conventional denture base design. The atraumatic potential of the denture base is indicated.

Fig. 2. Completed framework with marked ridge clearance.

Fig. 4. Prosthesis in the mouth shows no impingement on attached gingiva or alveolar mucosa.

THE

JOURNAL

OF PROSTHETIC

DENTISTRY

861

TIP&I FROM

This article applies the fixed partial denture hygienic pontic design to the denture base design of a class III mandibular removable partial denture. TECHNIQUE 1. Determine

the location of attached gingival and alveolar mucosa (Fig. 1). Make accurate maxillary and mandibular casts. Request crest of residual ridge relief on the laboratory work authorization to create a refractory cast that will not allow the designed framework to have residual ridge contact (Fig. 2). The undersurface of the frame should be at least 3 mm from the ridge and convex in cross section. A second refractory cast will facilitate future steps but is not necessary. Try in the completed framework. Complete wax-up (Fig. 3). Invest and process. Either fill in space beneath frame with plaster or use duplicate refractory cast for wax-up and processing. Ready denture for clinical placement by finishing and polishing (Fig. 4).

2. 3.

4. 5. 6.

7.

laminating

procedure

OUR

READERS

SUMMARY This technique applies accepted fixed prosthodontic pontic design to the denture base design of a tooth-bound removable partial denture. Patient feedback emphasizes the comfort and lack of bulk of the prosthesis compared with a removable partial denture of conventional design placed simultaneously. REFERENCES 1. Henderson D, Steffel VI. McCracken’s removable partial prosthodontics. 5th ed. St. Louis: CV Mosby, 1977:15-17, 101,123. 2. Stein RS. Pontic-residual ridge relationship: a research report. J PROS-

~~~~D~~~1966;16:251-84. Reprint

requests to:

COLONELE.GRANTESHELMAN,JR. ~~THMED GP PSC #ll,Box6149 APO AE 09132

for thermoformed

mouthguards

.

J. Milward, LBIST,a and R. G. Jagger, BDS, MScD, FDSRCSb University of Wales College of Medicine, Dental School, Cardiff, United Kingdom Thermoforming of blanks of thermoplastic materials such as a polyvinyl chloride and polyvinyl acetate-polyethylene is a commonly used laboratory method of producing mouthguards for contact sports.

aInstructor, Dental Technology. %enior Lecturer and Consultant, Department tistry. 10/4/40943

Fig.

862

of Prosthetic Den-

1. Name tag between laminated

blanks.

Prominent anatomic features on casts may result in overthinning of even the thickest blank. The correct thickness of the resultant mouthguard may be ensured by use of a laminating procedure to increase the thickness of the blank. In addition, the mouthguard may be personalized with the athlete’s name, team, or other relevant information inserted between the two laminated blanks (Fig. 1). Attempts have been made to thicken the blanks by transforming a blank onto the cast and trimming it to the correct dimension, then thermoforming a second blank on

Fig.

2. Laminated

blanks fused without

NOVEMBER

1992

VOLUME

air pockets.

68

NUMBER

5