This Site Deals With The Scietific Aspects Of Prosthetic Dentistry And Focusses Mainly On The Dental Students In Upper Egypt.


Some Denture Problems And Complaints.

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Some Denture Problems And Complaints.

Post  mo'taz mashaly on Fri Apr 02, 2010 3:23 pm

Common impression problems and faults
A feather edge indicates under-extension. This can be corrected by the addition of greenstick to the tray and repeating

Tray border shows through impression material. The tray should be reduced in the area of over extension and the impression repeated

Air blows. If small, can be filled in with a little soft wax. If large, retake the impression

Tray not centred. This is often at least partially due to using too much material so that it is difficult to see what is where. Remember to line up the tray handle with the patient's nose (except for ex-boxers)

Retching. A calm and confident manner is necessary for successful impressions. Gain the patient's confidence by attempting the lower first and use a fast-setting, viscous material. Distraction techniques may help, e.g. wriggling the toes on the left foot and the flngers of the right hand at the same time (patient, not the operator)

Patient with dry mouth: ZOE is contraindicated; use elastomer instead

Areas where tray shows through in otherwise good impression. Can be overcome by prescribing a tin-foil relief when dentures being processed

- The lower bilateral free-end saddle (Class I) This presents a particular problem because of a lack of
tooth support and retention distally, small saddle area compared to force applied, and distal
leverage on abutment tooth in function (which increased with resorption). Possible solutions include

1- Maximize indirect retention by placing rests and clasps on mesial aspect of the abutment tooth
and using plate design
2- Using a muco-compressive impression of saddle area to decrease displacement in function. The altered
cast technique
3- Use fewer, smaller teeth and maximize base extension
4- RPI system for distal abutment teeth. Mesial Rest, distal guiding Plate and mid-buccal I bar
During function the saddle moves tissue-ward and rotates around the mesial rest. The plate and I
bar are constructed in such a way as to disengage from the tooth and avoid potentially harmful
5- Stress-breaker design (advantages more theoretical than practical
6- Use precision attachments (beware of overloading abutments

- Class IV Can sometimes avoid unsightly clasps anteriorly by the use of:

1- A flange engaging a labial alveolar undercut
2- A rotational path of insertion2 utilizing rigid minor connectors that are rotated into proximal undercuts anteriorly
3- Inter-proximal undercuts, which may allow minimal display of clasps- hidden clasps
4- An acrylic spoon denture held in place by the tongue

- Multiple bounded saddles: A horseshoe design, which utilizes guide planes for retention, may be indicated

Common problems and possible solutions
Over-extension of flanges. Reduce

Under-extension of flanges. Try a temporary wax addition to flange first, to check effect of extending it. If this is satisfactory a new impression is required

Teeth outwith neutral zone. Remove offending teeth and replace with wax which can be trimmed until correct

Incorrect VD. If too small, can increase by adding wax to the occlusal surfaces of teeth, but if too large, will need to replace lower teeth with wax and re-record VD

Occlusal discrepancy or anterior open bite or posterior open bite. Replace lower posterior teeth with wax and re-record VD

Too little of upper anterior teeth visible. Reset anterior teeth to correct position and ask lab to adjust occlusal plane accordingly

Too much of upper anterior teeth showing. The effect of reducing the length of the incisors can be judged by colouring incisal region with a black wax pencil and then indicating desired change in position to lab

Inadequate lip support. An increase in support can be assessed by adding wax to the labial aspect of the upper try-in

A new try-in will be required if large errors are being corrected or if any doubt still exists about the occlusion


- Pain
This can be due to a variety of causes, including roughness of the fitting surface, errors in the
occlusion, lack of FWS, a bruxing habit, a retained root, or other pathology. Forward or lateral
displacement of a denture due to a premature contact can lead to inflammation of the ridge on the
lingual or lateral aspect, respectively. With continued resorption bony ridges become prominent and
the mental foramina exposed, which can lead to localized areas of specific pain
- Pain from an individual tooth on P/P
Excessive load and/or traumatic occlusion
Leverage due to unstable denture
Clasp arm too tight
Inadequate lining under amalgam restoration failing to insulate against a galvanic couple with
metal denture

- Looseness
This more commonly affects the lower than the upper denture
Denture faults
Incorrect peripheral extension
Teeth not in neutral zone
Unbalanced articulation
Polished surfaces unsatisfactory
Patient factors
Inadequate volume or amount of saliva
Poor ridge form
Improper adaptive skills, e.g. elderly patient

- Burning mouth This can be due to:
1- local causes: e.g. increased VD or sensitivity to acrylic monomer, or
be unrelated to the denture (e.g. irritant mouth washes);
2- systemic causes: e.g. the menopause deficiency states, cancerophobia, xerostomia

- Difficulty with f, v → incisors too far palatally
- Difficulty with d, s, t → alteration of palatal contour, incorrect overjet and overbite
- S becomes Th → incisors too far palatally, palate too thick
- Whistling → palate vault too high behind incisors
- Clicking teeth →increased vertical dimension, lack of retention

- Cheek biting
Check first those teeth are in neutral zone. If satisfactory, decreased buccal 'overjet', i.e. reduce
buccal surface of lower molars (provided normal bucco-lingual relationship

- Retching
- Map out extent of sensitive area on palate using a ball-ended instrument and firm pressure, and check extension of denture

- Palateless dentures may be a solution, but their retention is poor
- Training dentures. These can take the form of a simple palate to which teeth are added
incrementally, starting with the incisors
- Implants and a fixed prosthesis

- The grossly resorbed lower ridge Resorption is progressive with time, which is a good argument for avoiding rendering young patients edentulous. The mandible resorbs more quickly than the maxilla which exacerbates the problem of retention for -/F. Management is dependent upon the severity of the problem and the patient's biological age:
- Minimizing destabilizing forces upon the lower denture, e.g.
(1) maximum extension of denture base;(2) decrease number and width of teeth;
(3) increase FWS; (4) lowering occlusal plane
- Neutral zone impression technique
- Surgery
- Implants

-Recurrent fracture Apart from carelessness, this is usually caused by occlusal faults or fatigue of the acrylic due to continual stressing by small forces. Flexing of the denture can occur with flabby ridges, palatal tori, and following resorption. Notching of a denture, e.g. relief for a prominent frenum, can also predispose to fracture. Treatment depends upon the aetiology, but in some cases provision of a metal plate or a cast-metal strengthener may be necessary

mo'taz mashaly

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Join date : 2010-04-02
Age : 31

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