Overextension of Denture Borders
Slight overextension is preferred to slight underextension.
Remember, however, overextension is prejudicial to denture retention.
To examine the lower denture for overextension:
- Instruct patient to protrude tongue slightly until the tip rests upon the lower lip
- Place your index fingers on the occlusal surfaces of the lower teeth to determine if the lower denture remains firmly seated on the denture-supporting structures
If the denture lifts, consider 3 possiblities:
- Overextension in the region of the genioglossus muscle (contracts w/ forward movement of the tongue to dislodge denture) Anterior portion of denture lifts
- Overextension in the region of the premolar-molar area (denture dislodges by contraction of mylohyoid) Entire denture lifted from position
- Overextension of the extreme distolingual border of the lower denture (dislodgement of the forward movement of the retromylohyoid curtain) Entire denture dislodged from position and moved forward
To test buccal and labial flanges of the lower denture for retention, cheeks and lips are drawn outward. Keep index finger of the other hand on occlusal surface of the teeth on the same side. If denture lifts, border may be overextended.
Test buccal and labial flanges of the upper denture for retention the same way except hold index finger of the opposite hand in contact with palatal vault
Whartons (submaxillary duct)
- Occasionally a lower denture can cause complete or partial closure of Whartons duct
- This is clinically manifest by enlargement of the submaxillary gland
- The gland will usually return to normal soon after removal of the denture
- If mild duct closure, mild discomfort often disappears by itself during the adjustment period
- Sometimes a reduction of the lingual flange thickness, without disturbing the border, gives relief (avoid excessively reducing the border)
Faulty Vertical Dimension
It takes patients from 2 3 weeks to accustom themselves to dentures, so it is difficult to judge this early on, but some things to think about are:
Stomatopyrosis (burning mouth)
Action of the Denture as a Foreign Body
Contraindications to a Denture Reline
From: Perspectives in Prosthodontics
(Dr. Kenneth Barrack, Medical University of South Carolina)
Signs/Symptoms Causes Solutions
Fullness under nose
Depressed philtrum and/or nasolabial sulcus
Upper lip sunken in
Shows too much of the teeth
Whistle on "S" sound
Lisp on "S" sound
"Th" and "T" sounds indistinct
"T" sounds like "Th"
"F" and "V" sounds indistinct
Tongue and cheek biting
Fiery redness of all tissues contacted by denture, including tongue and cheeks
Redness of bearing tissues
Pain in TMJ
General feeling dentures are not right, but with absence of pain (patient has high pain tolerance)
ESTHETICS OF DENTURES
Labial flange of maxillary denture base too long or too thick
Labial flange of maxillary denture base too short or too thin
Maxillary anterior teeth too far lingual
Vertical dimension too great
Incisal plane too low
Cuspids and laterals too prominent
Technique setup, the alignment of the teeth are too regular
All teeth same shade
Lack of grinding incisal edges and angles
Lack of individualizing gingival contours and color of denture base
Too narrow an air space on the anterior part of the palate
Too broad an air space on the anterior part of the palate
Inadequate interocclusal distance
Maxillary anterior teeth too far lingual
Improper position of maxillary anterior teeth either vertically or horizontally
COMFORT OF DENTURES
Posterior palatal seal too deep
Sharp posterior palatal seal
Malocclusion in that area
Inaccurate denture base (esp 1Ú stress bearing areas)
Bubbles in acrylic resin
Vertical dimensions too great
Inaccurate denture base
Centric occlusion not in harmony with centric relation; drives lower denture forward
Patients habit, wants to masticate in protrusive
Overextended labial flange
Pressure on anterior palatine foramen
Pressure on posterior palatine foramen
Pressure on mental foramen
Posterior teeth edge to edge (minimal reduction of buccal aspect of teeth)
Posterior teeth too far lingual or buccal
Denture base allergy
VDO too small
Centric occlusion not in harmony with centric relation
Function of Dentures
Overextension of borders and posterior limit
Loss of posterior palatal seal
Dehydration of tissues due to medications or alcohol
"Flabby" tissues displaced when making impressions
Loss of posterior palatal seal (same as above)
Anterior teeth placed too far labially
Poor denture foundation ("flabby" anterior tissues)
Improper incising habits
Overclosure of the VDO
Posterior teeth too far lingual, crowds tongue
Too great a VDO
Immediately upon insertion
Delayed gagging (2 wks 2 mo post)
Centric occlusion not coincident with centric relation
Lack of confidence in retention
The Complete Denture Remount Procedure
Contributed by Dr. Ana Arnold
(from Leary, JM, Diaz-Arnold, AM, Aquilino, SA. The complete-denture remount procedure. Quintessence International 1988;19(9)623-629.
Purpose: Correction of denture occlusion under controlled conditions no matter what the cause of the occlusal disharmony.
- Reduces patient participation
- Done on solid base
- Dry field
- Clear visibility
- Corrections made away from patient
Procedure to remount a denture begins at the time the processing of the denture is complete. It can be broken into four phases: two laboratory and two that involve patient manipulation. The sequence would be initial laboratory correction, patient interocclusal records, laboratory correction, and finally patient evaluation and finalization of denture occlusion. The first laboratory phase may not be done by you, the dentist, and can be done by the laboratory technician, depending on your laboratory directions and philosophy.
The basic procedures are as follows:
- Preliminary laboratory occlusal adjustment
- Patient chairside tissue surface and peripheral extension evaluation and adjustment
- Laboratory occlusal adjustment utilizing interocclusal records to mount complete dentures
- Denture insertion and post insertion care
Preliminary laboratory occlusal adjustment involves occlusal adjustments resulting from processing error that occurs in the laboratory. Adjustments are done in the labs before delivery to the dentist.
Patient participation involves the evaluation and necessary adjustment done by the dentist on the tissue surface and periphery of the complete denture which results in a properly fitting prosthesis. At this time interocclusal records, using the patients new and properly adjusted maxillary and mandibular dentures are made for remounting these complete dentures.
Laboratory occlusal adjustment is the procedure of denture adjustment done at the laboratory bench after remounting the prosthesis on the articulator
Denture insertion is the final delivery of the denture. It includes intraoral inspection for accuracy of laboratory occlusal adjustment and review of home care instructions for the prosthesis and the patients mouth. These instructions are sent home with the patient.
More detailed breakdown of this remount procedure is as follows:
- Preliminary laboratory occlusal adjustment
- Unflask complete denture
- Reattach indexed maxillary and mandibular dentures to articulator and correct processing errors
- Preserve facebow relationship with remount index
- Remove, finish and polish complete denture
- Make maxillary and mandibular denture remount casts with plaster blocking out undercuts
- Mount maxillary denture cast to articulator using facebow index
- Patient participation
- Try-in, evaluate, and adjust complete denture bases and extensions
- Undesirable pressure spots PIP adjustment
- Complete basal seat with no over or under extension by using disclosing wax or PIP
- Make centric relation occlusal index on patient
- Mount mandibular complete denture remount cast with denture to the articulator
- After mounting, verify index by repeating centric relation and checking this with the remounted prostheses on the articulator
- 3. Laboratory occlusal adjustment
- Adjust centric relation discrepancies
- Adjust eccentric movements lateral working, balancing, and protrusive to develop
- Smooth movement
- Balanced occlusion (when desired)
- Mill in denture (monoplane teeth set flat only)
- Use a maximum of 10 strokes each
- Right lateral (RL), left lateral (LL), and protrusive
- The end result is contact between the incisal guide pin and incisal table
- Denture insert
- Re-adjust and remount when necessary
- Reinforce previous instructions and oral hygiene instructions.
The following is a step by step laboratory occlusal adjustment that will result in elimination of occlusal errors of anatomic teeth. A different procedure is used with monoplane teeth set flat.
- Adjustment is accomplished by selective grinding permitting both tooth form and occlusion to be retained.
- Articulating paper/ribbon of minimum thickness is used, thicker paper gives inaccurate markings and deceptive results.
- Centric relation deflective contacts are adjusted first.
- Complete dentures cannot be loose on the remount casts. It may be necessary to sticky wax the denture to the casts to prevent movement.
- Place articulating paper between complete denture teeth and lightly tap together. Both sides can be done at same time by fastening paper together in from with a paper clip.
- Basic rule: Grind fossas and deflective inclines and not cusp tips.
- Repeat marking and grinding until posterior teeth have contact in centric occlusion.
- During centric occlusion marking and grinding, incisal guide pin is raised 1 mm out of contact to compensate for the thickness of the wax interocclusal record.
- REMEMBER: After centric occlusion has been perfected the centric cusps must not be shortened.
- REMEMBER: The maxillary lingual cusps and the mandibular buccal cusps are usually centric cusps.
- After centric occlusion, deflective contacts are eliminated. The incisal guide pin is placed in contact with the incisal guide table and kept in contact during elimination of eccentric deflective movements, working and balancing.
- Place articulating paper between teeth on both sides of the arch and move articulator into lateral movement. I f the pin raises form the incisal table, reduce the appropriate marking.
- Reduce the appropriate non-functional cusp inclines on the working side first lingual incline of maxillary buccal cusps or buccal incline of mandibular lingual cusps.
- Reduce the appropriate cusp inclines on the balancing side. The lingual incline of mandibular buccal cusps are reduced before the buccal inclines of the maxillary lingual cusps.
- Marking and grinding is continued in lateral movement until the incisal pin stays flat and contact is made on as many posterior teeth as possible. Contact on all posterior teeth is ideal
- REMEMBER: Grinding to correct occlusion in lateral movement is usually limited to non centric cusp inclines. These include the lingual inclines of the upper buccal cusps and the buccal inclines of the lower lingual cusps on the working side. The lingual inclines of the lower buccal cusp on the the balancing side are reduced before the buccal inclines of the upper lingual cusps.
- After correction of right and left lateral movement, deflective contacts in protrusive are addressed.
- Relief is accomplished for protrusive interference on the distal inclines of maxillary cusps and mesial inclines of mandibular cusps.
- Light posterior contact is desirable in protrusive movement as long as the incisal guide pin stays on the incisal guide table.
- Anterior teeth should just clear without interference. This is usually addressed during the trial arrangement, but adjustment may be necessary
- Elimination of occlusal errors with rational teeth set to a flat occlusal plane is accomplished on the lower arch. The maxillary teeth are sanded flat with "220 wet or dry" sandpaper on a flat surface. This arch is then maintained while adjustment are made on the mandibular teeth.
- Finalization of the adjustment can be accomplished with milling past. All ground teeth should then be light polished to provide smooth movements.
Barrack, K. DENTUREREFERENCE©. Perspectives in Prosthodontics, American College of Prosthodontics 1997.
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