Dental Prosthetics

Types of Fixed Dental Prostheses

Individual Crowns

These are replicas of the visible part of the tooth. Modern crowns are made from zirconium dioxide, metal-ceramic, or ceramic / E.max glass-ceramic. Their lifespan, depending on the material and care, ranges from 7 to 20 years. The type of crown is chosen based on the budget and the position of the tooth in the dental row.

• For the front part of the mouth, where appearance is important, E.max glass-ceramic or zirconium crowns with color and transparency gradients are recommended.
• In the chewing area, strength is most important. Metal-ceramic or zirconium crowns are suitable here.

Advantages:

• They restore the shape and function of damaged or lost teeth.

Disadvantages:

• When a crown is placed on a natural tooth, the tooth is prepared and sometimes the nerve is removed.

Dental Bridges

A dental bridge is a unified structure consisting of 3-5 connected crowns. The end crowns are attached to the supporting teeth (premolars/molars) on both sides of the problem area or to titanium implants. Bridges are made from E.max glass-ceramic (up to 3 crowns), metal-ceramic, or zirconium. Their lifespan is about 7 years.

Advantages:

• They restore chewing function when 1-3 teeth are lost.
• Strong and blend seamlessly into the row of teeth.
• Quick adaptation.

Disadvantages:

• Strong supporting teeth are required for placement, capable of withstanding chewing forces.
• Preparation of the supporting teeth is necessary (they may become brittle and deteriorate over time).
• The bridge does not prevent bone loss in the area of the replaced tooth.

Implant-Supported Overdentures

An orthopedic structure that replaces all teeth in the upper or lower jaw. It consists of an acrylic or nylon base with attached crowns.

The number of crowns in the overdenture depends on the implantation method:

• All-on-4 – 10-12 crowns;
• All-on-6 – 14 crowns.

Types of overdentures:

• Permanent. Made of zirconium, E.max ceramic, or metal-ceramic. Fixed after complete osseointegration of the implants (up to 6 months).
• Temporary. Made of plastic. Fixed immediately after the placement of titanium implants.

Advantages:

• Restore the appearance and function of teeth within a day (temporary overdenture is fitted on the day of implantation or within 3-7 days).
• Evenly distribute the load on the implants, do not damage the oral tissues, slow down bone loss.
• Securely fixed on the implants (eliminating the risk of falling out).

Disadvantages:

• Extended rehabilitation period (permanent overdenture can be fitted no earlier than 3 months after implantation).
• High cost.

Indications for Fixed Prosthodontics (in English)

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

Types of Removable Prostheses (in English)

• 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:

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

Advantages:

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

Disadvantages:

• Lifespan of up to 5 years.
• The hard base can irritate the gums and cause discomfort when chewing.
• 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.
• Can affect speech and taste. Adaptation to the prosthesis is necessary. A full upper jaw prosthesis covers the palate, impairing taste perception.
• Ineffectively restores chewing function, not suitable for hard food.
• The porosity of acrylic leads to staining from food dyes and bacterial accumulation.
• Does not prevent the reduction of jawbone volume, worsening the prosthesis's fixation and increasing the risk of it falling out.

Nylon Prostheses

A more attractive and comfortable alternative to acrylic prostheses, made from flexible dental nylon, facilitating adaptation to artificial teeth.

Advantages:

• Comfort. Nylon is flexible, easy to insert and fix in the oral cavity. It is lighter and thinner than acrylic prostheses.
• Safety. Unlike acrylic, nylon does not contain methyl methacrylate, which can cause allergies.
• 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:

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

Acry Free

Acry Free is based on a latest-generation monomer-free material. Its semi-transparent plastic base is sufficiently rigid and resistant to constant chewing forces. Ceramic or plastic crowns give it an appealing look. Clasps made of acrylic resin securely hold the prosthesis in the mouth. Acry Free combines the advantages of nylon and plastic prostheses.

Advantages:

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

Disadvantages:

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

Clasp Prostheses

These are removable orthopedic constructions with a metallic, arch-shaped frame, covered on top with pink acrylic. Artificial crowns are attached to them. The rigid metal arch structure helps to evenly distribute pressure on the jawbone, extending the life of the prosthesis and slowing down bone atrophy.

Depending on the type of attachment, there are different types of clasp prostheses:

• On telescopic crowns. The system consists of two parts: a removable (artificial crown) and a supporting (tooth with a metal cap). This is an expensive, but aesthetic and durable method of attachment.
• With attachments. Micro locks for firm fixation in the mouth. They are aesthetic but require preparation of the supporting teeth for installation.
• With clasps. These are metallic hooks that attach the prosthesis to the supporting teeth. However, the metal elements are visible when speaking, and the main load is on the gums, which can cause discomfort.

Advantages:

• Lifespan of about 7 years. With proper manufacturing and care, the prosthesis can last up to 10 years, significantly longer than other removable prostheses.
• The prosthesis does not cover the palate, making it comfortable to wear and chew, does not affect speech, and prevents the gag reflex.
• Reliable fixation on the supporting teeth with fastening elements and a metal arch. Minimal risk of the prosthesis falling out while speaking and chewing.
• 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:

• The prosthesis is not applicable when the entire dental arch is missing.
• 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.
• Increased load on the supporting teeth can lead to premature wear and bone loss in the area of the defect.
• 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.

QuattroTi

A new generation clasp prosthesis without metal parts. With QuattroTi, the arch and retaining hooks are made from an aesthetic and strong technopolymer based on nylon (Acetal Resin Dental D). This material is 15 times stronger than acrylic and more aesthetic than clasp prostheses with metal clasps.

Advantages:

• Lifespan of more than 7 years.
• The material is stable under various conditions, moderately flexible, does not irritate the gums or teeth, and is securely fixed in the mouth.
• Damaged retaining elements can be easily replaced.
• The prosthesis can be flavored to create a pleasant taste in the mouth, such as vanilla or chocolate.
• Does not affect speech, comfortable to wear. The adaptation period is up to 7 days.
• 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.
• No prior preparation of the supporting teeth is required for attachment.
• The color of the artificial crowns and base is matched to the color of the patient's enamel and gums.

Disadvantages:

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

When Removable Prosthetics are Recommended

• In the absence of several teeth or the entire dental arch.
• For the temporary restoration of the appearance and function of teeth before implantation.

Comparison of Removable and Fixed Dentures

Micro-Prosthetics

Micro-prosthetics is a method of fixed prosthetics. It is used to restore the enamel or integrity of a tooth when 50-60% of the hard tissue is lost. In the Biodent dental clinic, the following types of micro-prostheses are used:

Inlays

These are micro-prostheses that restore damaged parts of the front and chewing teeth. Regardless of the material used, the inlays are manufactured in a laboratory.

Inlays are categorized based on the material:

• 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. 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.
• Metal-Ceramic:
  Inferior in quality compared to full ceramic, often fall out.
• Composite:
  Made from standard filling material, more expensive than simple fillings, but not different in quality, change color over time. Rarely used.
• Metallic Inlays:
  Preferred for repairing molars.

Made from metal alloys:

• 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:

• 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.
• 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.

Dental Posts

A dental post is a threaded rod that serves as the foundation for a crown. The post is placed into the root canal to evenly distribute chewing pressure.

Post prosthesis is used when more than half of the tooth's crown is destroyed and a conventional filling is inadequate.

Veneers

Thin coverings with a thickness of 0.2-0.5 mm for the front teeth. Used to enhance the appearance of front teeth in cases of:

• Changing the color of the enamel when whitening is ineffective;
• Increased sensitivity;
• Large gaps between teeth;
• Chips and cracks in the enamel;
• Minor misalignments of teeth;
• Tetracycline staining of teeth.

Veneers are made from various materials:

• Composites. Less durable but aesthetically pleasing. Last up to 5 years, made directly by the dentist. More affordable. Repairable.
• E.max glass-ceramic. Very aesthetic and sufficiently durable. Ceramic veneers are created in a dental laboratory by pressing. Lifespan up to 20 years.
• Zirconium dioxide. Zirconium veneers stand out for their high durability and a maximum lifespan of up to 25 years. They are manufactured using CAD/CAM milling. Pure zirconium is less aesthetic compared to ceramic. The zirconium base is covered with a ceramic veneer to achieve a natural look.

Steps of Dental Prosthetics

Consultation and Diagnosis: Examination of the oral cavity, assessment of the teeth, medical history collection. Making a jaw X-ray, choosing a method for dental restoration.

Preparation: Oral hygiene - removal of plaque, treatment of caries, extraction of unusable teeth, preparation of supporting teeth for a bridge. Creation of a 3D model of the teeth for the prosthesis. In the case of implants – bone augmentation and placement of titanium implants.

Fitting and Placement: Adjustment and correction of the prosthesis. Securing the finished prosthesis in the mouth.

Denture Care Instructions

1. What should I do if a tooth is lost?

You have two options: A crown on an implant or a bridge on teeth. If the adjacent teeth are healthy, an implant with a crown is preferable. This method does not affect the adjacent teeth, distributes the load evenly, prevents bone loss, and recreates the appearance and feel of a real tooth. The titanium implant lasts a lifetime, the crown up to 20 years, depending on the material.

A bridge is suitable if the adjacent teeth are damaged but strong enough to serve as supports. The bridge provides a good appearance but does not prevent bone loss at the replacement site and transfers the entire load to the supporting teeth. The supporting teeth are prepared before the bridge is placed, sometimes involving nerve removal. This can lead to their weakening and destruction, complicating future prosthetic treatments.

2. Dental Prosthesis Care

Fixed prostheses should be cleaned twice a day, especially at the areas where they touch the gums and where plaque accumulates. An irrigator is recommended for removing food particles from hard-to-reach areas.

Removable prostheses require more thorough care:

They should be removed in the morning and evening for cleaning with a special brush and mild paste or children's soap. To maintain cleanliness and extend the life of the prosthesis, it is recommended to soak it in a disinfecting solution for about 20 minutes, 3-4 times a week (the product should be chosen in consultation with a doctor). After each meal, the prosthesis should be rinsed under running water.