A Note On Denture Coping Technique....

Definition

A copy denture preserves the polished surface of the existing prosthesis while allowing modifications to be carried out to the fitting and occlusal surfaces of a complete denture. As a patient's adaptive potential decreases with age the maintenance of the shape of the original polished surface results in less adjustment of the supporting musculature being required. Therefore the title 'Copy denture technique' is really a misnomer as It is only rarely that an exact copy of an existing denture will be required.

Indications

1.      An elderly patient presenting with upper and lower complete dentures which have been satisfactory for many years but are now loose or worn.

2.      A patient with a history of denture problems where it may be useful to make controlled modifications in the copy denture of the most successful previous dentures

3.      Previous immediate dentures which require replacing after bone resorption following extractions.

4.      Second 'spare' set of dentures.

Advantages

·         No alteration or mutilation of existing denture as occurs in a reline or rebase.

·         No period for patient to be without dentures as occurs in a reline or rebase.

·         Reduced number of clinical stages

·         Simple duplication procedure

Technical support for such techniques is variable,various clinical techniques are available

1.                                  Use of reversible hydrocolloid to copy dentures

                                     Murray/Woolland technique

3.                                     Replica record block technique

Standard copy technique

Definition- As previously described.

Indications- As previously described.

Advantages

• The reproduction of successful design features on which a patient's tolerance and control of the previous dentures depend.

• The accurate alteration of undesirable features.

• Simplified occlusal registration and a reduced number of clinical visits.

Disadvantages

 Increased charges may be made by commercial laboratories. The production of a template and the need for the technician to follow this exactly also often makes this technique unpopular amongst technical staff.

Procedure

 1. A mould of the original denture that is being copied is produced by whichever method the clinician wishes to use.

This is poured up, with the teeth in wax and the bases in selfcured acrylic. A stone duplicate is also poured as a guide to the original denture, both in respect of the polished surfaces and tooth position.

2. The wax and acrylic copy denture is then either used as a registration block or, if minimal occlusal alteration is required, taken to the trial stage.

3. The dentures are tried in and the occlusion and vertical dimension checked. If this is found to be satisfactory any undercuts are removed from the baseplates and a wash impression is taken within both the upper and lower bases using a closed mouth technique.

4. A master cast is then poured and the finished dentures processed in the normal manner.

Copy denture for severe tooth wear

Definition

A duplicate denture made with as few modifications to the previous existing denture as possible.

Indications

Patients who present with mutilated dentures  that they can comfortably wear and who have a history of intolerance to conventional replacement of these dentures. Clinically, there may be a place for providing the patient with a copy of their old dentures with as few modifications as possible.This will improve the chances of patient acceptance of the new prosthesis.

Advantages

 It is likely that the patient's acceptance of and adaptation to such a denture will be high as it will not be different to their 'tried and trusted' set. A further advantage is the reduction in numerous remakes.

Disadvantages

 By following such a technique, the clinician may unknowingly copy faults that may in the long term cause such problems as TMJ symptoms and denture instability.