REMOVABLE PARTIAL DENTURES Design Basics

Robert L. Schneider, D.D.S., M.S.

INDICATIONS FOR REMOVABLE PARTIAL DENTURES

Replacement of teeth in distal extension situations Following recent extractions as an interim basis during healing On a long edentulous span where Ante's Rule cannot be satisfied Where cross-arch bilateral bracing is needed. Indicated in a dental arch weakened by

periodontal disease Esthetics in the anterior region. Sometimes a better esthetic result can be obtained

using an RPD than a fixed restoration, especially when there has been a loss of soft/hard tissues surrounding the abutment teeth

Excessive loss of the residual ridge is more easily compensated for and more esthetic with replacement by an RPD with a properly contoured and properly colored acrylic resin base

Economic considerations. Most often it is less costly to the patient to restore a full arch with a removable partial denture than with fixed restorations. The patient's financial status must be considered in treatment planning

As a diagnostic tool in evaluating the patients vertical dimension of occlusion if that dimension is to be altered during definitive treatment Functions of RPD components:

SUPPORT - resists movement toward the tissue. RETENTION - resists movement away from the tissue. RECIPROCATION - resistance to retentive forces, cross tooth and cross arch. BRACING - resistance to movement in a horizontal plane or mastecatory forces.

Provided by contact of the components of the framework with vertical tooth surfaces parallel to the path of placement.

INDIRECT RETENTION - prevention of movement away from the tissue surface CONNECTION - makes all components rigid. STABILITY - culmination of all of the above. The quality of a prosthesis to be

firm, steady, constant and not subject to change of position when functional stresses are applied.

OCCLUSAL RESTS - Cr-Co 1.0-0.7mm minimum thickness. The positive seat should be 0.5 mm deeper than the peripheries. Facial-lingual dimension is 1/2 to 2/3 the distance of the cusp tips. Mesial-distal dimension should eliminate the fossa and extend to a transverse triangular ridge. On a natural tooth with a restoration, the rest should extend to natural tooth structure or be confined to the restoration. Occlusion and placement of centric stops is a problem. General rules for occlusal rests: 1. Do not rest in an occlusal stop unless it cannot be avoided. If the stop is eliminated with a rest, the patient will not have that centric stop when the RPD is out of the mouth. The stop should usually be replaced by providing occlusion on the rest, which usually requires considerable adjusting when seating and fitting the framework. Also, when occlusion is allowed to take place on a rest because of the differences in hardness of materials, excessive wear takes place on natural teeth, gold or resin restorations. Porcelain can wear the rest rapidly. The rest also can become work hardened and fracture, rendering the RPD ill fitting and non-functional. This is one of the most common types of framework fracture in RPD's.

2. Do not remove the last natural tooth centric stop on one side of the arch. This leaves the patient without a centric stop on one side of the arch when the RPD is out of the mouth, which can result in an unstable occlusion and may precipitate occlusal problems. Also try not to remove the most posterior natural tooth centric stop on one side of the arch because this distributes the occlusal load throughout the length of the mandible and helps to prevent overclosure. Never remove the last centric stop on a natural tooth, as this could leave that tooth in an unstable occlusal situation and may result in tooth movement and continual changing of the occlusion. MAJOR CONNECTORS - The connectors should be rigid, not impinge excessively on the soft tissues, be biocompatible, and be self cleansing. Mandibular major connectors should begin 1.0 mm superior to the activated floor of the mouth. This is measured with a periodontal probe from the marginal gingiva and transferred to the diagnostic cast. Measure the midline, canine, premolar and molar areas, if these teeth are present. You need a minimum of 8.0 mm of space to use a lingual bar,because the lingual bar is 4.0 mm in height and can be no closer than 3.0 mm to the marginal gingiva of the teeth. If you don't have this amount of room you probably will be using a lingual plate major connector. Maxillary designs have significantly more variations. The borders of the maxillary major connector that are located on keratinized palatal tissues are "beaded",

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usually to 1/2 the depth of a #6.0 round bur. The purpose of the bead is to provide a positive contact area on the connector with the soft tissue. The bead will help seal the RPD to prohibit food impaction. The beading is done by the DENTIST on the master cast before sending the cast to the laboratory. ALL MAJOR CONNECTORS WILL BE RIGID IN DESIGN AND NOT FLEXIBLE. If flex is noted in the major connector when it is returned from the laboratory it should be remade on the back-up master cast. MINOR CONNECTORS - These should possess all the characteristics of major connectors and also cover as little tissue as possible. There are four types of minor connectors; proximal, embrasure, surface and base retentive mechanisms. The proximal minor connectors or GUIDE PLANES have dimensions of 1 1/2 - 3.0 mm occlusogingival height and 1/2 cusp tip width for the buccolingual dimension. They are usually trapezoid or rectangular in shape and can be slightly triangular if a prosthetic tooth is involved and esthetics are critical. EMBRASURE CONNECTORS should not be a "tongue toy" or food trap. If the lingual or palatal is not plated then the minor connectors should exhibit a minimum of 5.0 mm mesial-distal dimension and 3.0 mm occlusogingival dimension for the MANDIBULAR major connector and 5.0 mm mesial-distal dimension and 6.0 mm occlusogingival dimension for the MAXILLARY major connector. The FOOT is a type of proximal minor connector. The proximal plate extends cervical to contact the attached gingiva on the crest of the ridge and extends onto the ridge 1-2.0 mm. This metal portion of the proximal plate is called the foot of the minor connector. The foot is used to evaluate the fit of the framework to the cast and forms a portion of the internal finish line, when a plastic-metal-plastic base is used. The foot should not contact the marginal gingiva. Other minor connectors are the BASE RETENTIVE MECHANISMS, usually mesh or lattice when a "sandwich" type of base is used. Advantages of mesh:

Joined in multiple points to the major connector Allows more options in placement of wrought wire clasps Easier to wax for technician

Advantages of lattice:

Large openings = greater bulk of resin = increased strength of resin Should be placed to minimally interfere with placement of prosthetic teeth Easier to place tin foil substitute when processing Easier to pack acrylic resin during processing

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CLASPS - Clasps have minimal requirements to insure they are providing, retention,

stability, reciprocation and bracing components to the RPD design and these are: Provides support by using rests or ledges Provides retention by proper contact of the desirable undercut Provides cross tooth reciprocation, which is resistance to the retentive portion of the

clasp Encirclement - encompasses at least 180o of the tooth Be totally passive when seated A cast clasp should flex only in the terminal 1/3 A reciprocating clasp should not flex

There are basically two types of clasps based on the direction the clasp approaches the

undercut: Circumferential, suprabulge, or pull clasp Bar, infrabulge, or push clasp

The quality of clasp retention is dependent on several factors:

The angle of cervical convergence which is the degree of undercut below the height of contour at a given path of placement and removal. The greater the angle of cervical convergence, the greater the retentive potential of the clasp

The depth of undercut engaged by the retentive clasp arm. Obviously the more undercut, the more retention is produced.

The amount of surface area of the clasp arm in contact with the undercut. The more of the clasp arm in contact, the more retention is provided.

The flexibility of the clasp arm relates to several factors such as: length of the clasp arm bulk of the clasp arm the material from which the clasp is fabricated, gold is twice as flexible as Cr-Co the physical form of the clasp arm, cast vs. wrought wire, with wrought wire being

the more flexible the cross-sectional shape such as round, 1/2 round and 1/2 pear, with 1/2 pear

being the least flexible The type of clasp such as infra- or supra- bulge. The infrabulge type clasps

theoretically provide and increase in retention because of increased tripping action

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The direction the clasp arm approaches the undercut. The more at right angles the retentive clasp approaches the undercut the more of an increase in retention is provided

Frictional resistance depends on the coefficient of friction of the clasp arm and abutment materials. The more friction, the more retention, theoretically

Taper of the clasp. It should be uniform tapered so that the retentive 1/3 is 1/2 the thickness of the point of origin. If the taper is not uniform, the clasp may flex in an undesirable area resulting in work fatigue and premature fracture.

FITTING THE FRAMEWORK - RPD frameworks should always be fit and adjusted

intraorally when they are returned from the laboratory and after they are visually inspected by the dentist. Use a disclosing media such as Kerr's Disclosing Wax or spray Occlude. Perform a static and physiologic adjustment to insure minimal or no binding on the distal extension guide planes. The minimum criteria for acceptable fit of a framework are:

Simultaneous point contact of all rests in the positive rest seat Simultaneous point contact of reciprocal components Framework appears seated when viewed from the occlusal and when the occlusal

components are checked with an explorer Framework slides to place, not with an audible click Contact with at least three natural teeth (when present) Contact of guide planes with natural teeth in occlusal 1/2 to 1/3 No orthodontic forces on the natural teeth Totally passive when in place

Frequent areas of binding in RPD frameworks:

Shoulder of circumferential clasps Guide planes Marginal ridges of rests Interproximal of lingual plates Other areas depending on what metal is used

WHY DON'T THE RPD FRAMEWORKS FIT WHEN THEY ARE RETURNED FROM

THE LABORATORY?????? Or (Damn the Technicians...Full Speed Ahead!)

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There are multiple reasons such as cast abrasion, inaccurate impressions etc. One of the

main inaccuracies is the casting process. Pulskamps research shows that: Nickel-Chrome (Ticonium 100) - is .35% smaller in the AP dimension and

.48% smaller in the cross arch dimension Chrome-Cobalt (Vitallium) - is .46% larger in the AP dimension and .79%

larger in the cross arch dimension Type IV gold (G-3 Ney) - is .01% larger in the AP dimension and .31% larger

in the cross arch dimension

The following principles of RPD design are submitted for your observation in the quest for the "BIG PICTURE".....

1. Keep the design as simple as possible (KISS RULE). Do not put a component on the RPD

unless it is needed to fulfill one or more of the following functions: support, reciprocation (cross-tooth and cross-arch), bracing, indirect retention, connection (major and retention, minor), occlusion and, stabilization. Planning for eventual loss of a tooth would be another reason for adding a component part to an RPD.

2. Eliminate anterior edentulous spaces. Elimination of anterior edentulous spaces by a

fixed partial denture can greatly simplify the RPD design and will help to eliminate the technical difficulties of placing anterior prosthetic teeth on an RPD. The technical difficulties encountered in using anterior prosthetic teeth on an RPD are:

Matching natural tooth color with available shades of prosthetic teeth Obtaining adequate retentive mechanism on the RPD framework for the

prosthetic tooth and/or denture base material Matching the denture base shade to the mucosa shade Eliminating undesirable undercuts on the proximal of anterior abutment teeth

which can result in unesthetic spaces (black triangles) between the tooth and RPD.

3. Eliminate all but one posterior edentulous space per quadrant. Elimination of all but one

posterior edentulous space per quadrant by using a fixed partial denture greatly simplifies the RPD design. This will help eliminate the technical difficulties of restoring multiple edentulous spaces in one quadrant and also decreases or eliminates the potential destructive forces on lone standing (pier) abutment teeth.

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4. Place a guide plane on all proximal surfaces adjacent to an edentulous space. RPD's

should have a minor connector on the proximal surface of all abutment teeth adjacent to an edentulous space. This proximal plate guide plane contact provides two main functions:

It determines the path of placement and removal of the RPD It places metal in contact with the natural tooth surface rather than acrylic resin or

porcelain of the prosthetic tooth or denture base. The metal will not wear like the acrylic resin so the guide plane will remain in tact as designed with less chance of fracture and disruption of the path of insertion and removal of the RPD

5. Rest on all teeth adjacent to an edentulous space with the following exceptions:

Teeth incapable of providing adequate support, poor crown/root ratio, or uncorrectable periodontal disease

If the abutment tooth has improper anatomy for the indicated rest, such as anterior teeth with inadequate cingulum contour, then an adequate rest must be provided by a fixed restoration, acid-etch type restoration, or an attachment included in the fixed restoration

6. Place retention on the abutment tooth adjacent to the edentulous space with the following

exceptions: You may not want to place retention on teeth anterior to the stabilizing fulcrum

line as the retentive clasp may produce torquing forces on the tooth under functional forces

Retention may not be place on the abutment tooth of an anterior modification space for esthetic reasons

7. Provide retention on both sides of the arch. Retention on both sides of the mouth will

limit the rotation of the RPD around the AP fulcrum lines along the edentulous ridges. 8. Use the simplest clasp possible for the survey line and undercut of the abutment tooth.

Clasps should be selected on the basis of: The survey line on the tooth. The survey lines usually can be modified to suit

your needs The location and depth of the undercut

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The presence of muscle or frenum attachments which will interfere with infrabulge bar clasp approach arms

The presence of soft/hard tissue undercuts that could interfere with infrabulge bar clasp approach arms

The amount of retention desired. Infrabulge generally provide greater amounts of retention than infrabulge type clasps

Research has shown success and failure with all clasp design systems. Most any clasp can be

used if the RPD framework is properly fitted to the mouth and adequate support is obtained from the edentulous ridge, using a reline or rebase if necessary. NO perceptible occlusal movement of the indirect retainer by visual or tactile examination is a desirable end result of proper RPD delivery and maintenance. Movement may be detected as tissue-ward force is placed alternately on the occlusal surfaces of the prosthetic teeth on the distal extension denture base and the indirect retainer, indicating need for improvement of the basal seating contact areas and/or extensions.

9. Select clasp designs, undercuts, and relation of the clasp to the survey line so that all

clasps have the same amount of retention, when possible. 10. Provide cross-arch reciprocation when possible. Design the RPD so that a retentive

clasp on one side of the arch is counteracted by a retentive clasp on the opposite side of the arch. Retention on the facial or lingual of an abutment tooth on one side of the arch should be reciprocated by facial or lingual retention on a tooth in the same AP location or as close as possible because of the location of the remaining teeth in the partial edentulous arch and anatomy of the abutment teeth.

11. Provide for cross-tooth reciprocation. Place a reciprocal guide plane or reciprocal clasp arm on the tooth surface 180o from the direction of force applied by the retentive clasp tip.

12. Provide indirect retention in tooth-tissue supported RPD's. No indirect retainer is

necessary for tooth supported RPD's because the resistance to movement around the various fulcrum lines is counteracted by the components of the RPD involved with retention and support.

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13. The metal framework should contact at least three natural teeth. If the metal RPD framework contacts at least three teeth, ideally in positive rest seat preparations, the relationship of the RPD framework to the teeth and soft/hard tissues can be carefully evaluated. Contact on a lingual place can be counted as one of the three contact points. If a framework only contacts two points a stable relationship cannot be evaluated as three points determine a plane. The contact of the palatal major connector or dental base to the residual ridge or hard palate tissues is not accurate enough to count for the solid contact of the metal framework on a natural tooth.

14. Plan to develop maximum support from the available denture bearing tissues for tooth-

tissue supported RPD's. Maximum support from the denture bearing tissues for the tooth-tissue supported RPD's is obtained by properly extending the denture base to the limits dictated by moderate activity of the muscles of facial expression and mastication in the vestibules. Maximum support is best obtained by properly extended border molded impressions, and in distal extension RPD's, by the use of the corrected or an altered cast impression technique. A corrected cast is not often indicated in maxillary distal extensions because of the quality of the supporting tissues and anatomy of the area, compared to the mandibular arch.

15. Use the simplest denture base for the situation. The simplest denture base is the plastic-

metal-plastic combination. This type of denture base cannot be used if there is inadequate space vertically or mesial-distal for the base, denture base retention minor connector, and prosthetic teeth. In limited space situations a different base should be selected. Other selections available include metal only or combinations of metal and plastic. The minimum amount of space necessary for a plastic-metal-plastic base is 8.0 mm vertically and 5.0 mm mesial-distal, to provide optimal strength and esthetics to the restoration, with minimal chances of fracture.

Complete Denture Insertion and Post-Insertion Problems: Cause, Diagnostic Procedures and Treatment

I. Retention Problems A. Problem: Maxillary Denture Lacks Retention at Time of Insertion.

Possible Cause Diagnostic Procedure Treatment 1. Tissue contours or fluid balance changed since time of impression.

Patient closes firmly on cotton rolls for 5 min. to determine if retention improves.

Patient reassurance if retention improves.

2. Incorrect posterior palatal seal. a. Seal placed on non-

displaceable tissue. (Denture too short posteriorly)

b. Seal on movable tissue

(Denture too long posteriorly)

c. Inadequate depth and seal does not extend into hamular notch. d. Posterior border and seal does not extend into hamular notch.

Place pressure on lingual of incisors and canines while supporting denture. Denture dropping indicates incorrect seal. Check posterior extension by placing transfer ink on posterior border. Dry tissues and insert denture to transfer ink line to palatal tissues. Relate line to vibrating line. Use transfer ink to relate posterior border to vibrating line. Add wax seal along posterior border and check for improvement in retention. Transfer ink line to palate with denture. Slide blunt instrument along distal slope of tuberosity until instrument falls into notch. Relate to ink line.

Treatment depends upon type of error. (See Below) Relieve original palatal seal. Extend denture with wax or compound. Add seal with impression wax or beading wax until retention is improved. Replace wax/compound with autopolymerizing resin as a lab procedure. Shorten denture to vibrating line. Add seal with autopolymerizing resin/or/ create seal with wax until retention improves. Replace wax with resin (Lab Procedure) Replace wax with autopolymerizing resin (lab Procedure) Extend posterior border into hamular notch with wax or compound. If retention improves replace wax with resin as a lab procedure.

3. Inadequate clearance for labial or buccal frenum.

Pull lip or cheek down firmly in area of frenum while supporting denture to check for dislodgement.

Use P.I.P. or disclosing wax to determine area for adjustment.

4. Posterior palatal seal causing tissue rebound and denture displacement.

Use P.I.P. to check. Complete displacement of P.I.P. indicates excessive depth. Patient will usually complain of pain or pressure.

Relieve seal, checking with P.I.P. until retention improved and discomfort corrected.

5. Thin tissue covering over prominent mid-palatal suture or tours.

Displacement of P.I.P. when alternating pressure placed on posterior teeth.

Relieve area of P.I.P. displacement.

6. Dry mouth because of alcoholism, radiation medication or disease.

Place saliva substitute to check if retention is improved.

Prescribe saliva substitute as rinse and for placement in denture.

7. Inaccurate denture base because if inaccurate impression or warpage of finished denture.

Place thin mix of alginate impression material in denture and seat firmly in mouth. Thick areas of alginate indicate poor tissue adaptation.

Reline or remake the denture.

8. Posterior border too short or too thin to fill buccal vestibule.

Retract check and visually check.

Extend border with compound or impression wax and border mold. Replace impression material with resin as a lab procedure.

9. Short labial flange or excessive notch for labial frenum.

Retract lip horizontally and visually check. Denture drops when patient smiles widely.

Extend border with compound or impression wax. Replace impression material with resin as a lab. procedure.

B. Problem: Maxillary denture loosens when patient opens widely. Possible Cause Diagnostic Procedure Treatment 1. Posterior borders too thick or too long.

Pull cheek out and down over border to check for dislodgement of denture.

P.I.P. or disclosing wax on border. Overextension or excessive thickness may be indicated by only a thin line of displacement of indicating material. Adjust area of show through.

2. Interference with coronoid process if mandible by distobuccal flange.

Place finger in anterior teeth and have patient protrude mandible and move it from side to side. Feel for movement of denture.

Use P.I.P. or disclosing wax to indicate area for adjustment. Adjust show-through.

C. Problem: Maxillary denture loosens while patient is speaking. Possible Cause Diagnostic Procedure Treatment 1. Inadequate posterior palatal seal.

Place pressure on lingual of incisors and canines while supporting denture. Denture dropping indicates incorrect seal.

Treatment depends upon type of error. (See section I A-3)

2. Interference with coronoid process of mandible.

Place finger on anterior teeth and have patient protrude mandible and move from side to side. Feel for movement or dislodgement of denture.

Same as I B-2

3. Posterior border too long or too thick.

Pull check out and down over border to check for dislodgement of denture.

Same as I B-1

4. Short labial flange or excessive notch for labial frenum.

Retract lip horizontally and visually check. Denture drops when patient smiles widely.

Extend border with modeling plastic or impression wax. Replace impression material with resin as a lab procedure.

5. Notch for buccal frenum too thick or of insufficient size.

Grasp cheek and pull down and out in buccal fernum area. Move cheek anteriorly and posteriorly and check for dislodgement.

Use P.I.P. or disclosing wax and repeat movements. Adjust show through areas.

D. Problem: Mandibular denture lacks at time of insertion. Possible Cause Diagnostic Procedure Treatment 1. Change in tissue contours or fluid balance since impression.

Cotton rolls placed between posterior teeth and patient closes firmly for 5min. Check for improvement.

Reassurance if retention improves.

2. Borders too wide to too long in labial or buccal flange areas.

Patient places tip of tongue on the mandibular incisors and opens. Lips and cheeks are lifted up and around borders to check for lifting of denture.

Place P.I.P. or disclosing wax and repeat lifting of lip and cheek while holding denture in position. Adjust show-through areas.

3. Buccal flanges under extended.

Pull cheek outward and upward at a 45degree angle and move cheek forward and back. Space between border and cheek indicates unerextension.

Extend and border mold with compound or impression wax. Replace with resin as a lab procedure.

4. Labial flange under extended.

Pull lip out in horizontal direction and move it from side to side. Space between border and mucobuccal fold indicates under extension.

Same as I D-3

5. Inadequate notch for lingual fernum.

Patient forcibly places tongue to touch posterior palate. Check for lifting of denture.

P.I.P. to indicate area for adjustment.

6. Overextension or excessive thickness of lingual border in molar area.

Patient lightly places tip of tongue into right and left buccal vestibules. Note forceful lifting of denture.

Place disclosing wax on border on side of forceful lifting. Repeat tongue movement while holding denture firmly in place. Adjust show-through areas.

7. Overextension or excessive thickness in distolingual area.

Patient protrudes tongue from mouth. Forceful lifting indicates need for adjustment of denture.

Disclosing wax is placed around border on distolingual one third of denture. While holding denture in place, patient forcefully protrudes tongue to indicate area for adjustment. Thin distolingual border to 2mm.

8. Under extension of lingual border in molar/and/or/ distolingual area.

Apply impression wax on border. Patient lightly protrudes tongue from mouth, into each cheek and opens widely. Wax remaining with dull surface appearance indicates lack of contact and under extension.

Add additional wax or use compound to extend border and border mold. When retention is improved, replace with resin as a lab procedure.

9. Inadequate lingual seal. Lengthen and widen lingual border from premolar to premolar with impression wax. Patient licks lips, clears buccal vestibules and retrudes tongue to touch posterior palate. Improved retention indicates inadequate seal.

Replace wax with resin as a lab procedure.

10. Retracted tongue position (tongue doesnt lie comfortably with lip touching lingual incisors and lateral borders not contacting teeth.)

Place dentures firmly in mouth. Ask patient to open slightly. Observe relationship of tongue to denture.

Tongue exercises twice daily. Place resin nodule on lingual of mandibular incisors to serve as reference point for tip of tongue.

11. Lack of adequate neuromuscular control. (elderly stroke, disease.)

Patient observation. Evaluate patients ability to manipulate lips and tongue on command. Observe facial musculature for hypotonicity.

Use of denture adhesives for a few weeks until control of denture improves. Improve contours of polished surfaces if they are not ideal.

12. Posterior teeth set too lingual crowding tongue.

Lingual cusps should lie within triangle formed by lines connection the lingual and buccal aspects of the retromolar pad with the mesial contact point of the properly positioned canine.

Reposition teeth on denture base and process with resin. Minor errors may be corrected by grinding lingual surfaces.

13. Poorly contoured polished surfaces. (Should be contoured so that lower fibers of buccinator and tongue will add in retention.)

Polished surfaces too convex with denture base wider than borders.

Reshape denture base to acceptable contours.

14. Dry mouth because of alcoholism, medication or disease.

Place saliva substitute in denture to check if retention improves.

Prescribe saliva substitute as rinse and for placement in denture.

E. Problem: Maxillary denture loosens at different times of day. Possible Cause Diagnostic Procedure Treatment 1. Heavy secretion of mucinous saliva from palatal salivary glands.

Tissue surface of maxillary denture covered with ropy saliva. Usually affects a first time denture wearer. Heavy carbohydrate diet may contribute to problem.

Remove and clean denture several times daily; use of astringent mouth rinses; reassurance that palatal glands tend to atrophy when covered.

2. Periods of excessive dry mouth because of alcoholism, radiation medication or disease.

Place saliva substitute to check if retention is improved.

Prescribe saliva substitute as rinse and for placement in denture.

F. Problem: One or both dentures loosen while eating. Possible Cause Diagnostic Procedure Treatment 1. Teeth set too far buccal to crest of ridge.

Lingual cusps should fall within triangle formed by buccal and lingual aspects of retromolar pad and the mesial contact of the canine.

Reposition teeth on denture base.

2. Occlusal plane higher than retromolar pad.

Check relation of occlusal plane to anatomic landmarks.

Reposition teeth of both dentures.

3. Interceptive contact in occlusion.

Carefully check relationship of teeth throughout the chewing process.

Remount and correct posterior occlusion. Hollow grind lingual of maxillary anterior teeth if necessary to eliminate anterior interferences in function range of movement.

4. Inadequate neuromuscular control with new dentures.

Rule out all possible errors of dentures.

Reassurance that it will take time for oral structures to accommodate to new contours of new dentures. Adhesives may be used for 1-2 weeks until control of denture improves.

II. DISCOMFORT PROBLEMS

A. Problem: Excessive salivation. Possible Cause Diagnostic Procedure Treatment 1. Strangeness of new denture. Usually occurs first 72 hours

of wearing new dentures. Reassurance. Patient should be counseled about problem prior to denture insertion. Probably caused by reflex parasympathetic simulation of the salivary glands.

B. Problem: Sore mouth at 24 hours or subsequent post insertion appointment. (during first 2 weeks) Possible Cause Diagnostic Procedure Treatment 1. Pressure areas from impression or warpage of denture. Lack of relief in non-yielding areas such as tori, lingual tuberosities, exostoses or sharp bony areas.

Examine bearing area for reddened areas or red areas with central ulceration. Swelling of inflamed are helps to identify pressure area with P.I.P.

P.I.P. to indicate area for adjustment. May encircle area requiring adjustment with transfer ink.

2. Borders too long, too wide, or border left sharp.

Examine border areas for red line, long slit or cut in tissue; or a well-circumscribed reddened area or, a grayish white area that appears to be sloughing.

Use P.I.P. or disclosing wax and manipulate borders to determine area of overextension. Area may be encircled with transfer ink to help identify overextension. Borders must be rounded.

3. Errors in occlusion causing movement of denture.

Carefully check occlusion. Irritated areas are on ridge slopes.

Remount and correct occlusion.

4. Overextension in masseter area of mandibular denture.

Disto-buccal contour of mandibular denture does not assume 45degree angle from top of pad, and soreness is on lingual of mandible. Place disclosing wax on disto-buccal borders and have patient close very firmly on cotton rolls to activate masseter muscle.

Adjust areas where wax is displaced.

5. Insufficient relief over undercuts.

Use combination of P.I.P. and transfer ink to locate exact area on denture. Area may be reddened and/or uncerated.

Adjust denture until patient feels improvement. Do not over relieve denture.

C. Problem: Non-specific pain with a new denture. Possible Cause Diagnostic Procedure Treatment 1. Pressure over zygomatic process.

Palpate and apply pressure over zygomatic area to check for pain.

Locate pressure area with P.I.P. and adjust.

2. Disto-buccal border of maxillary denture base too wide.

Place finger on maxillary anterior teeth and have patient protrude mandible and move from side to side. Feel for movement or dislodgement of denture.

Use P.I.P. or disclosing wax to indicate area for adjustment.

D. Problem: Generalized soreness after repeated adjustments. Possible Cause Diagnostic Procedure Treatment 1. Clenching and bruxing. Shiny wear facets on teeth,

observation and questioning of patient.

Patient awareness, stretch and relaxation procedures. Keep denture out at night or wear a soft mouth guard over denture.

2. Inadequate Interocclusal distance. (freeway space)

Utilize rest position and phonetics to determine if rest position has been encroached by vertical dimension of occlusion.

Remount and reposition or equilibrate teeth restoring adequate Interocclusal distance (freeway space.)

3. Errors in occlusion. (Soreness on crest or slopes of residual ridge)

Carefully remount and analyze occlusion. Check for interferences at position of habitual closure if it differs from centric relation. (retrognathic patients)

Correct occlusion. May have to remount at habitual closing position to help in eliminating interferences.

4. Post menopausal endocrine changes or endocrine therapy.

Careful history relationship of soreness to initiation of drug therapy or a change of medication.

Consult with physician for possible interruption of drug therapy or change in medication.

5. Low tissue tolerance due to nutritional deficiencies.

Thorough dietary analysis. Dietary counseling; with knowledgeable physician if problem persists.

6. Low tissue tolerance due to disease such as uncontrolled diabetes, pemphigus vulgaris.

Thorough history. Rule out all possible local causes.

Referral to physician for diagnosis and treatment.

E. Problem: Cheek biting. Possible Cause Diagnostic Procedure Treatment 1. Insufficient horizontal overlap of posterior teeth.

Observe relationship of posterior teeth. Should be approx. 2mm. Of horizontal overlap.

Normal relationship: round in buccal cusps of mandibular molars; crossbite: round in buccal cusps of maxillary molars.

2. Insufficient clearance between denture bases and distal to last tooth.

Check for clearance of 3-4mm.

Thin denture bases to allow space for tissues of check.

3. Sharp buccal cusps. Run finger over buccal surface of posterior teeth.

Round over sharp edges and polish.

4. Replacement teeth extend too far posteriorly.

Teeth set over retro molar pad or tuberosity.

Remove most posterior tooth and grind it off denture base.

F. Problem: Tingling and/or pain of lower lip. Possible Cause Diagnostic Procedure Treatment 1. Pressure over mental foramen.

Only ridges with extensive Resorption. Palpate firmly in area of mental foramen to reproduce symptoms.

Use transfer ink to encircle area. Relieve area liberally.

G. Problem: Burning sensation of upper lip and side of nose. Possible Cause Diagnostic Procedure Treatment 1. Impingement of nasopalatine nerves exiting incisive foramen.

P.I.P. to verify pressure over incisive foramen. Area may be reddened.

P.I.P. or place transfer ink on papilla to locate area of denture for liberal relief.

H. Problem: Patient complains of sore throat. Possible Cause Diagnostic Procedure Treatment 1. Overextension and ulceration on soft palate.

Use transfer ink to determine overextension onto movable tissue.

Shorten and reestablish a posterior palatal seal.

2. Overextension beyond hamular notch, disto- buccal of maxillary denture, disto-lingual of mandibular denture or onto pterygo-mandibular raphe above retromolar pad.

Inspection for inflamed or ulcerated tissues in these areas,

P.I.P. or disclosing wax and transfer ink to locate area of denture for adjustment. Adjust and polish denture.

III. GAGGING WITH DENTURES A. Problem: Gagging at time of insertion. Possible Cause Diagnostic Procedure Treatment 1. Nervousness at receiving first denture.

Rule out other possible causes. A Piece of hard sweet-sour candy to occupy tongue when symptoms appear first day or two only.

2. Posterior border too long. Apply transfer ink to posterior border of denture and insert after drying tissues. Relate ink line to vibrating line.

Adjust denture if it extends beyond vibrating line. Reestablish a posterior palatal seal.

3. Posterior border thick. Inspect posterior border for thickness over mm.

Reduce thickness from overextended and thin distolingual border to 2mm.

4. Disto-lingual flange pf mandibular denture too long or too thick.

Check to determine that disto-lingual borders are not over 2mm. thick. Use disclosing wax or P.I.P. to check for overextension.

Shorten borders if overextended and thin distolingual border to 2mm.

5. Maxillary occlusal plane too low triggering tongue gagging.

Simulate contact on tongue with mouth mirror to check for gagging response.

Reposition teeth on denture base or remake denture.

B. Problem: Delayed gagging begins subsequent to day of insertion. Possible Cause Diagnostic Procedure Treatment 1. Heavy mucinous saliva form palatal salivary glands escaping from posterior border.

Remove denture and observe thick ropy saliva.

Remove and clean denture frequently. Use of astringent mouthwash. Reassurance that secretion will eventually decrease

2. Mandibular teeth set too far lingual triggering tongue gagging.

Verify correct buccal-lingual position and lingual aspects of retromolar pad and the incisal contact of the cuspid.

Grind lingual surfaces of mandibular posterior teeth or reposition teeth on denture.

3. Vertical dimension of occlusion increased beyond physiologic limits.

Use rest position and phonetics to verify adequate Interocclusal distance. (freeway space)

Reposition or equilibrate teeth to increase the Interocclusal distance.

IV. SPEECH PROBLEMS A. Problem: Patient has difficulty speaking with first or new denture. Possible Cause Diagnostic Procedure Treatment 1. History of corrected speech problems as a child.

All denture causes of problem ruled out. Take a detailed history. Patients often forget early lisps or other problems that were corrected by time or therapy.

Enlist the aid of speech therapist.

B. Problem: Whistle on s sounds. NOTE: Normal s sound is created by hiss of air as it escapes from median groove of tongue when tip of tongue is just behind maxillary incisor teeth. Lateral borders of tongue in contact with posterior teeth and tissue. Possible Cause Diagnostic Procedure Treatment 1. Median groove of tongue too deep. Maxillary anterior teeth set too far labial or insufficient denture base material on lingual of maxillary anterior teeth.

Add wax to anterior palate to create normal s curve of palate and have patient speak words with s sound.

Replace wax with resin if whistle is corrected.

2. Posterior teeth set too far lingual or denture base material too prominent causing median groove to deepen.

Combination of relieving posterior denture base and add wax to anterior palate.

Replace wax with resin if whistle is corrected.

D. Problem: S sound sounds as SH or TH. Possible Cause Diagnostic Procedure Treatment 1. Median tongue groove too shallow and air escaping at lateral borders of tongue: Excessive base material lingual to anterior teeth or anterior teeth set too far lingual.

Problem with S sound not pronounced.

Relieve anterior palatal denture base.

2. Air escaping at lateral borders of tongue because of lack of denture base material restoring tissue.

S sounds as slushy sh or a lisping th. Build up lingual tissue roll with wax until problem is corrected.

Replace wax with resin.

Overview of RPD designSchneider manual Table