A complete denture is a dental prosthesis that replaces all the missing natural teeth and its supporting tissues in a single arch (jaw) or both the arches (both upper and lower jaws).
What Is The Purpose of a Complete Denture and Who Needs One?
As mentioned above, complete denture or CD is given to an individual when there is a need to replace all the teeth in the mouth with the supporting tissues, to re-establish the normal form and the function of the mouth while regaining the aesthetic value (the appearance) of the face.
So an individual who has lost all of the natural teeth in both upper and lower jaws or one of the jaws due to various reasons such as dental caries, periodontal problems, old age, or teeth lost due to congenital disorders, etc, is an ideal candidate for a complete denture.
Complete Denture Guidelines: How Should A Perfect One Be?
A perfect complete denture should fit well on to the jaws and meet the following guidelines.
The ‘retention’ here, means the ability of the denture to hold on to the surface of the jaws without dislodging during activities like eating, chewing, talking or at rest.
The perfect denture should not get displaced from the alveolar ridge. of the jaws. There should be good contact between the tissues and the denture.
The retention of the denture depends upon the peripheral seal, volume of saliva, and contact area.
Usually, the retention of the lower denture is challenging to achieve, due to the movement of the tongue and floor of the mouth. So it is normal for the lower dentures to be less stable than the upper ones.
This is an important feature which requires the complete denture to resist vertical movements towards the ridge. The denture should cover maximum space without impinging on the tissues underneath like the mental tubercle or the frenum of the mouth.
Good Muscle balance
The complete denture should not get dislodged during the functional movements by the muscular forces of lips, tongue, or cheeks.
The denture should have the ability to resist displacement during any kind of function carried out in the oral cavity. This feature is similar to the feature of retention, discussed earlier.
Good Occlusal Balance
The denture should not get dislodged during functional jaw movements with the teeth in contact. This can be achieved by balanced articulation.
This is the area where the muscular forces are in balance. So the placement of teeth in this zone is good. This feature should be incorporated in an ideal complete denture.
Complete Denture Fabrication; Step By Step
The fabrication of a complete denture for your mouth is done by your dentist in the following, step by step, manner. The procedures involved below may get too technical to understand, for a common reader. Please keep that in mind.
History Taking and Clinical Examination
History taking and clinical examination are essential in deciding whether the individual is fit for this dental procedure or not. So the first step of the denture fabrication is ‘history taking’.
A good detailed history needs to be taken by the dentist to assess if the patient is a new denture wearer or old.
Patient assessment is crucial because the dentist will need to know his/her expectations about the outcome of the denture.
An individual with already existing good denture who needs a replacement is a happy patient and the expectations may be very low.
While on the other hand, the individual with existing faulty denture who needs a new one may have expectations but will be ‘ok’ once the problem would be solved in the new complete denture prosthesis.
Then there are some other individuals who after not being satisfied with a good previous denture would have visited many dentists in the past for replacement dentures.
And then there is another category of stubborn individuals who will never be happy even if the dentist offers them the perfect denture.
Clinical examination including intraoral and extraoral examination will be done by your dentist at this stage.
Extraorally (outside the mouth), it’s important to look for the facial contours of the person, drooping lip angles, loss of lip bulge, angular cheilitis, the vertical height of the mouth, etc. And that’s what the dentist is going to do at this phase.
The dentist may also look for the presence of any Temporomandibular joint pain or clicking sounds at the joint or any pain/tenderness experienced in the muscles of mastication (chewing, eating and grinding function).
Intraorally(inside the mouth), the mucosal health will be checked by the dentist who will look for the presence of an ulcer, hyperplasia, etc.
Next, the salivary viscosity needs to be assessed. Also, determining the type and quality of the edentulous ridge (the jaw without teeth) and the degree of bony resorption are important.
If there are any tubercle or tori or flabby ridges present in the mouth the complete denture design may need alterations.
If the individual is a previous denture wearer, then the dentist may look for any denture related candida infection.
In case the individual is allergic to Acrylic, alternative material will be considered. Polycarbonate or nylon are used as alternate base materials. Porcelain teeth are also an alternative to acrylic teeth which may be used in the final complete denture.
The primary impressions of the arches or the jaws are recorded by the dentist or the prosthodontist using edentulous stock trays and impression compound or alginate impression material. The desired extensions are marked in the impression in order to help the technician proceed with the lab work.
Once the impressions of the jaws are taken the dentist disinfects the impressions and sends it to the laboratory where they make the special trays using these impressions. These special trays are then used to take the secondary /master impressions or final impressions of the edentulous jaws.
Master Impressions or Secondary Impressions
Special Trays for Secondary Impression for Complete Denture
Special trays that are created in the laboratory are made of self-cure acrylic material. The trays are separated from the cast by wax spacers. These trays usually have a stop or a handle. They may be perforated and have vent or relief areas.
The purpose of the master impression or the final impression is to record the maximum denture bearing area with an excellent peripheral seal, relieve friable tissues, assessment of the functional depth and width of the sulcus.
The special tray border is modified to accommodate the green stick compound which is used to record the peripheral area in the mouth especially the sulcus area.
The trays are tried in the patient’s mouth prior to the procedure to check for any overextensions.
Secondary Impression of the Upper Jaw or the Maxillary Arch
The dentist warms the green stick compound and places it on the edges of the tray and then places it in the palatal area (upper jaw area) of the patient to record the borders. The dentist then records the functional sulcular depth by moving the cheeks and lips of the patient.
Secondary Impression of the Lower Jaw
As done in the case of the upper jaw, the dentist places the tray on the ridge of the lower jaw (mandible) and records the sulcus depth. This is done by asking the patient to move his/her tongue, protrude the lower jaw, and move it laterally.
The master impression of the denture bearing area is finally made using Zinc oxide-eugenol impression material.
If the patient has a dry mouth, any elastomeric impression material can be used instead of zinc oxide.
The secondary impressions are then disinfected and sent to the laboratory where the master casts and record blocks are made and sent back to the dentist for occlusal registration.
Jaw Relation Or Occlusal Registration
The goals of this step are to record the vertical height of occlusion, to register the jaw relation in the retruded contact position of the lower jaw, to determine the lip support, the occlusal planes, the midline and the shade, size, and shape selection of the artificial teeth.
The dentist uses wax record blocks to register the jaw relation. These wax record blocks are made stable on shellac base plate or heat cure acrylic.
Accordingly, the wax block plate is placed in the patient’s mouth to record the occlusal plane.
The upper anterior occlusal plane is registered as 2-3 mm below the relaxed level of upper lip parallel to the line between the pupils of the eye.
The upper posterior occlusal plane is trimmed along with the anterior plane along the line parallel to the ala-tragus line.
The upper midline is marked in the block, using the center of the philtrum as the guide or the facial symmetry in some cases.
The lower block is placed in the mouth and trimmed till the upper and lower rim contact evenly.
Vertical dimensions are checked in different ways. One way is assessing the closest speaking space of 1 mm between the two blocks. The second way is to use the Willis bite gauge or calipers. If it is not correct, then either add wax or trim the wax accordingly.
If the dentist is happy with the final registrations and if the patient is comfortable with the vertical height and fullness of the lip, notches are marked on both sides and final registration will be taken using bite registration paste.
Artificial teeth selection for the dentures will be done by the dentist at this stage.The size, shape, and shade are selected according to the patient’s skin color, face shape, and individual preferences. The artificial teeth can be made up of acrylic or porcelain depending on the case.
The final record blocks are sent to the lab along with the selected teeth for the trial set up.
Try-in for Complete Denture
The dentist inserts the trial denture to check for correct vertical height, anterior and posterior occlusal planes, and jaw relations. This is done to verify the correctness of measurements taken during the jaw relation and occlusal registration stage.
This is also done to evaluate the patient’s satisfaction with the aesthetics and appearance.
If any corrections are needed, the dentist does the chairside adjustments. If not re-registration and retrial may be needed.
If the patient and the dentist are satisfied with the results, the trial dentures are sent to the laboratory for the fabrication of final prosthesis.
Once the fabrication is done and the dentist receives the final complete denture, he/she examines the denture for any sharp edges or over extensions, before placing it in the patient’s mouth.
The heat cured acrylic denture is finally placed in the patient’s mouth. The dentures are then checked for occlusion, muscle balance, speech, smile, and appearance.
If the occlusal balance is not correct, it can be reexamined using articulation papers and accordingly selective grinding is done.
The peripheral borders are then examined for any over extensions and muscle balance.
The dentist then examines the speech of the patient, because it can get a bit difficult to speak in initial stages of getting a new denture. The patient education regarding denture wearing and maintenance will be given by the dentist at this stage.
Patient Instructions: Things To Keep In Mind While Getting A New Denture
The patient usually needs time to get adapted to the new dentures. If the individual is a first-time denture wearer, he/she may feel uncomfortable in the initial days of use. So a softer diet may be recommended.
Initially, there may be pain or discomfort but it is recommended to continue wearing the denture unless the pain is severe, in which case review to the dentist at the earliest maybe needed.
The denture needs to be worn full time for the first 2 weeks until the individual gets adapted.
The individual is required to habituate loud reading for a specific amount of time each day, wearing the denture, to get used to it and to improve the speech.
Maintaining The Denture
The denture needs to be stored in water in a box at night times to prevent shrinkage or drying out of the denture. This also helps in resting the muscles of the mouth which are otherwise actively engaged throughout the day.
You need to follow up with the dentist regularly after getting a new complete denture prosthesis. This is important for the dentist to assess how well you are coping with the dentures.
The dentist will also check the intraoral mucosa for any pain, discomfort or ulceration caused by the use of the denture.
The dentist will also reassess the occlusion and the speech.
If there is an issue in future with the retention of the denture or any kind of repair either fracture or detachment of tooth or so, then the dentist might recommend either rebasing or relining of the denture.
This procedure may need redoing of certain steps and sending it to the laboratory for the correction of the denture. The use of tissue conditioners can also be done according to the requirement.
The individual needs to wear the denture continuously to get habituated with its use which will also speed up the process of restoration of the form, and function of the mouth.