Insertion adjustment mylohyoid ridge

of denture

base surface

contacting

the

Louis J. Boucher, PhD, DDSa State University of New York at Stony Brook, School of Dental Medicine, Stony Brook, N.Y. After reading DuBrul and Sicher’s text,l the author began in 1954 to include an additional step in distal-extension removable partial denture and complete denture placement procedures.2 This step is important because of a decrease in the mandibular arch width during protrusive and lateral jaw movements. These movements tend to create aProfessorof Prosthodontics. 10/4/36317

pressure on the mylohyoid ridge. The pressure is greatest on the posterior region of the ridge because that part is closest to the insertion of the external pterygoid muscle. The mucoperiosteum covering the mylohyoid ridge is usually thin, with little or no connective tissue layer. During mastication, the mucoperiosteum is displaced between the denture base and the sharp mylohyoid ridge, making the entire mandible painful. It is not always possible to surgically reduce the sharp

Fig. 1. PIP applied to denture base. Note striations or brush marks created.

Fig. 2. Displacement of PIP caused by pressure on mylohyoid ridge. 900

JUNE

1992

VOLUME

6’7

NUMBER

6

TIPS

FROM

OUR READERS

mylohyoid ridge or protect it with a soft lining in the denture. Hence, the denture must be adjusted at the time of insertion or during postinsertion visits. TECHNIQUE Place pressure indicator paste (PIP) over the tissue surface of the denture base with a stiff, short, coursehaired brush. Brush on the PIP so that striations or the brush marks appear on the denture base. Such brush marks will enable the dentist to determine whether the PIP was rubbed off or flattened under pressure (Fig. 1). Place the fingers on the occlusal surfaces of the teeth and the thumbs under the jaw. While the patient is making protrusive opening and right and left lateral movements, press firmly on the occlusal surfaces of the teeth. Remove the denture from the mouth and examine the region of the mylohyoid muscle for pressure spots. Reduce minimally the denture base in the sites of the pressure spots over the mylohyoid ridge. Repeat the procedure at least three times or until no pressure spots appear. If the mylohyoid ridge is extremely sharp and only a

Technique

to diminish

J. David Duncan, James G. Fitchie, University

discomfort

faint line appears in the PIP, press the lingual flange against the mylohyoid ridge and adjust the denture base accordingly (Fig. 2). 5. After the pressure spots in the PIP are adjusted (except those on the primary stress-bearing regions), adjust the occlusion. 6. Place new PIP on the tissue surface of the denture and request the patient to occlude the teeth in all excursive movements. Again, adjust the pressure spots that are revealed. REFERENCES 1. DuBruI E, Sicher H. The adaptive chin. Sprim$eld, Ilk Charles C Thomas, 1954. 2. Renner RP, Boucher LJ. Removable partial dentures. Chicago: Quintessence Publishing Co, Inc, 1987:341-5. Reprint requests to: DR. LOUIS J. BOUCHER SCHOOL OF DENTAL. MEDICINE STATE UNIVFTWIY OF NEW YORK STONY BROOK, NY 11794-8706

from

DDS, MSD,* Gary W. Reeves, DMD,b DMDb

of Mississippi,

the palatal

and

School of Dentistry, Jackson, Miss.

aAssociate Professor, Director of Fixed Prosthodontics, Department of Restorative Dentistry. bAssociate Professor, Department of Restorative Dentistry. 10/4/37524

T his technique

describes the use of dichlorodifluoromethane spray to reduce the discomfort of the palatal injection. A small cotton pellet is saturated with the spray and then placed in contact with the palatal tissue for 5 sec-

Fig. 1. Saturation of the cotton pellet with dichlorodifluormethane

THE

JOURNAL

OF PROSTHETIC

injection

DENTISTRY

spray.

901