Dental Prosthetics

Indications for Fixed Prosthodontics

1. If all teeth are missing (full prosthesis on implants).
2. If a tooth is damaged by 50% or more, or is completely missing (single crown on the tooth or implant).
3. If several teeth in a row are missing (bridge on implants).

Types of Removable Prostheses

Removable prostheses are used to replace one, several, or all missing teeth. They consist of a pink base that mimics the gums, artificial crowns, and securing elements (in partial prostheses) that hold the structure in the mouth on the supporting teeth.

Full removable prostheses do not contain securing elements. They are held in the mouth by adhesion to the gums and mucous membrane. These structures are easy to remove and clean. They are also used to temporarily restore appearance and chewing function before fitting permanent prostheses.

Acrylic Prostheses

Known as plate prostheses, made from medical acrylic. Types:

1. Partial – when some teeth are missing;
2. Complete – when all teeth are lost;
3. On implants – a temporary solution for complete tooth loss until a permanent prosthesis is fitted on implants.

Advantages:

1. Production time up to two weeks.
2. Repairable in case of damage.
3. More affordable compared to other materials.

Disadvantages:

1. Lifespan of up to 5 years.
2. The hard base can irritate the gums and cause discomfort when chewing.
3. Residual monomers in acrylic can cause allergies, especially if the manufacturing technology is compromised. Modern prostheses made from the latest generation of acrylic minimize allergy risks.
4. Can affect speech and taste. Adaptation to the prosthesis is necessary. A full upper jaw prosthesis covers the palate, impairing taste perception.
5. Ineffectively restores chewing function, not suitable for hard food.
6. The porosity of acrylic leads to staining from food dyes and bacterial accumulation.
7. Does not prevent the reduction of jawbone volume, worsening the prosthesis's fixation and increasing the risk of it falling out.

Advantages:

1. Comfort. Nylon is flexible, easy to insert and fix in the oral cavity. It is lighter and thinner than acrylic prostheses.
2. Safety. Unlike acrylic, nylon does not contain methyl methacrylate, which can cause allergies.
3. Aesthetic appearance. The base and fastenings (for partial prostheses) are made of semi-transparent, elastic nylon matching the color of the gums, making them almost invisible in the mouth.

Disadvantages:

1. Lifespan of about 2 years.
2. Not repairable or rebaseable. In case of damage, a complete replacement is required.
3. Wears out quickly, loses shape and appearance, difficult to polish.
4. The flexible structure wears out quickly under constant stress, can injure the gums, and ineffectively distributes chewing force, accelerating bone tissue atrophy.

Advantages:

1. Lifespan of more than 7 years.
2. Lightweight and moderately elastic construction ensures comfortable use, fits well against soft tissues, does not irritate the mucous membrane.
3. Hypoallergenic material that does not contain toxic substances, does not absorb odors and food dyes.
4. More effectively distributes chewing pressure compared to nylon and acrylic prostheses, maintains its shape over time.
5. Capable of being repaired and retrofitted.
6. Attractive appearance, the semi-transparent base is hardly noticeable in the mouth.
7. Monolithic structure and smooth surface reduce plaque adhesion, making cleaning easier.

Disadvantages:

1. Cost is twice as high as that of removable acrylic prostheses.

Advantages:

1. Lifespan of about 7 years. With proper manufacturing and care, the prosthesis can last up to 10 years, significantly longer than other removable prostheses.
2. The prosthesis does not cover the palate, making it comfortable to wear and chew, does not affect speech, and prevents the gag reflex.
3. Reliable fixation on the supporting teeth with fastening elements and a metal arch. Minimal risk of the prosthesis falling out while speaking and chewing.
4. Quick adaptation, except for clasp systems, due to its compactness and good fit to the gums. Getting used to the prosthesis takes only a few days without significa discomfort.

Disadvantages:

1. The prosthesis is not applicable when the entire dental arch is missing.
2. Clasp prostheses with clasp fixation are less aesthetic – the metal hooks are visible when speaking and eating, especially in the front part of the mouth.
3. Increased load on the supporting teeth can lead to premature wear and bone loss in the area of the defect.
4. Metal parts of the prosthesis can cause galvanic effects, so it should be removed before cleaning, medical examinations, and physiotherapy. Some patients may experience an allergic reaction to the metal.

Advantages:

1. Lifespan of more than 7 years.
2. The material is stable under various conditions, moderately flexible, does not irritate the gums or teeth, and is securely fixed in the mouth.
3. Damaged retaining elements can be easily replaced.
4. The prosthesis can be flavored to create a pleasant taste in the mouth, such as vanilla or chocolate.
5. Does not affect speech, comfortable to wear. The adaptation period is up to 7 days.
6. Dental D is a robust material, resistant to falls, without monomers, with a smooth surface. The prosthesis does not cause allergies, does not absorb odors, and does not stain.
7. No prior preparation of the supporting teeth is required for attachment.
8. The color of the artificial crowns and base is matched to the color of the patient's enamel and gums.

Disadvantages:

1. The cost is 2-3 times higher than acrylic prostheses and about a third higher than clasp prostheses.
2. Regular visits to the orthodontist every 6-12 months are necessary to adjust the prosthesis and ensure its stable fixation.
3. As with all removable prostheses, the chewing force is not transferred to the jawbone, which can lead to its atrophy.
4. Clasps only hold the prosthesis on the teeth but do not distribute pressure. This can cause pain when chewing hard food.

Inlays are categorized based on the material:

1. Full Ceramic: Made of pressed E.max ceramic: provide high aesthetics and strength, but do not fit as tightly to the teeth as those made of zirconium dioxide.
2. Made of zirconium dioxide: produced using CAD/CAM technology. They are as strong as metal inlays and as aesthetic as E.max ceramics. They fit better to the tooth, reducing the risk of recurrent caries.
3. Metal-Ceramic: inferior in quality compared to full ceramic, often fall out.
4. Composite: made from standard filling material, more expensive than simple fillings, but not different in quality, change color over time. Rarely used.
5. Metallic Inlays – preferred for repairing molars.

Made from metal alloys:

1. Cobalt-Chrome / Silver-Palladium alloys – a more affordable alternative to gold. Made of polished metal. More durable than composite, but less than gold. Gold – the most durable metallic inlays. The softness of the alloy minimizes gaps between the microprosthesis and the tooth.

Types of inlays:

1. Post and core. Used for restoring heavily damaged teeth. Consist of a metal post in the root canal and a crown, onto which an artificial tooth is placed. Suitable if the tooth root remains and the adjacent teeth are healthy.
2. Restorative. Used when half of a molar is affected by caries. Manufactured in a laboratory, do not change color, do not shrink, protect against bacteria and diseases.