Prosthetic Teeth Introduction
Artificial teeth or prosthetic teeth are considered as major factor determining the chewing eficiency of patient with prosthesis. Variety of artificial teeth in term of anatomy and materials are available in market. One should know how to select correct teeth which is most suitable for particular patient. It is chapter focuses on important aspects of artificial teeth.
Table of Contents
Classification Of Prosthetic Teeth
According to Material Used for Fabrication:
- Acrylic teeth
- Porcelain teeth
- Composite teeth
Read and Learn More: Preclinical Prosthodontics Notes
- Acrylic teeth with amalgam inserts
- Acrylic teeth with metal occlusion.
According to Occlusal Anatomy of Teeth:
- Anatomical teeth
- Semi-anatomical teeth
- Nonanatomical teeth
Acrylic Teeth
Acrylic teeth are made up of acrylic, which bond chemically with denture base resin. They are available in various shapes and shades. They are most widely used denture teeth.
Indications:
- When opposing teeth are acrylic teeth.
- When opposing teeth has metal occlusion.
- When less interarch space is available (in such case acrylic teeth can be trimmed easily to accommodate in available space).
Acrylic Teeth Advantages:
- They chemically bond with denture base material.
- They can be trimmed very thin to fit in available space.
- They do not abrade the opposing natural teeth.
- They can be easily polished.
- They can be easily modified to established occlusal contact with opposite teeth.
- They have less/softer impact sound (sound produced when opposite teeth come in contact).
- Less traumatic to denture foundation.
Acrylic Teeth Disadvantages:
- They wear with time.
- Subjected to abrasion if cleaning done with abrasive/rough substances.
- Due to wear, masticatory efficiency is reduced over a period of time.
- Stain and discolor easily.
- May need to be replaced due to excessive wear.
- Rebasing is difficult as acrylic teeth chemically attached with denture base.
Interpenetrating Polymer Network Acrylic Resin Teeth (IPN Resin Teeth):
To overcome low wear resistance of conventional acrylic teeth, interpenetrating polymer network (IPN) were developed. For IPN, material with highly cross-linked copolymer is used. This material has minimum or no fillers.
Advantages of IPN acrylic resin teeth are:
- More harder
- More abrasion resistant
- More heat resistant
- More stain/discolor resistant.
Porcelain Teeth
They are made up of porcelain (ceramic). There is no chemical bonding between porcelain teeth and acrylic resin. Porcelain teeth have metal pins or diatoric holes in ridge lap area, these features helps in mechanical bonding between porcelain teeth and denture base acrylic resin.
Porcelain Teeth Indications:
- Used where interarch space is sufficient and teeth placement can be done without trimming.
- Used with well-formed ridges.
- When patient demands high esthetic.
- When patient abrades acrylic teeth in short time, porcelain teeth are selected.
Porcelain Teeth Advantages:
- More resistant to wear compared to acrylic teeth.
- Good esthetic.
- Does not stain or discolor easily.
- Rebasing can be done easily as porcelain teeth are mechanically attached to denture base with the help of metal pins and channels within teeth.
Porcelain Teeth Disadvantages:
- No chemical bond with acrylic denture base.
- If used, opposite to the natural teeth they cause abrasion of natural teeth.
- As porcelain is brittle material, chipping and fracture is common with porcelain teeth.
- They have sharp impact sound (clicking noise comes when porcelain teeth contact with opposing arch porcelain teeth).
- Causes more trauma to denture foundation.
Composite Teeth
Composite teeth bond chemically to acrylic denture base material. Composite teeth have greater wear resistance compared to conventional acrylic resin teeth. They are moreesthetic. They can be used opposing to natural dentition and opposing to acrylic teeth.
Acrylic Teeth With Amalgam Inserts/Stops
In some clinical cases the acrylic resin teeth are placed opposite to porcelain teeth (when two opposite arches are not treated at same time). In such cases acrylic teeth abrade very quickly due to opposite porcelain teeth.
To reduce this acrylic teeth wear, amalgam stops or inserts are prepared on acrylic teeth. To prepare these stops, cavities are prepares on occlusal surfaces of acrylic teeth and amalgam is placed in cavities.
The contacts are established with opposite teeth before amalgam sets completely. This will establish the amalgam stops with proper occlusal contacts. Whenever patient chews, the amalgam stops come in contact with the porcelain teeth and prevent the direct contact of acrylic with porcelain teeth and reduce acrylic wear.
Acrylic Teeth With Metal Occlusion
To reduce the wear of acrylic teeth when opposing teeth are natural teeth or porcelain teeth or metal restorations, the acrylic teeth are modified with metal occlusion. The occlusal surface of acrylic teeth is prepared and wax pattern is made over it.
Casting is done to convert the wax pattern in metal occlusion. The metal occlusion is then cemented to acrylic teeth to prepare acrylic teeth with metal occlusion.
Anatomical Teeth
Shape:
Cuspal angulation: 33° or more.
Synonyms:
Cusp teeth.
Anatomical Teeth Indications:
- Well-formed ridges.
- When teeth to be arranged in balanced occlusion (anterior and posterior simultaneous contacts of teeth in any centric or eccentric position).
- Patients with good neuromuscular control.
Anatomical Teeth Advantages:
- They have better chewing efficiency compared to semi anatomic and nonanatomic teeth.
- They have more natural appearance.
- They penetrate food more easily.
- Act as a guide for proper jaw closure.
- Resist rotation of the denture bases through cusp interdigitations.
Anatomical Teeth Disadvantages:
- More time-consuming procedure to arranged in balanced occlusion.
- Posterior teeth placement restricted by opposing fossa and cusps.
- Denture bases need frequent relining to keep occlusion stable and balanced.
- More occlusion disharmony during settling and dificult to correct by adjustment.
- Precise jaw closure and base stability required for interdigitation.
- Difficult to adapt to abnormal jaw relationship (class II and class III).
- Increased horizontal forces due to deep cuspal angulation.
Semi-Anatomical Teeth
Shape:
Cuspal angulation: 20°.
Synonyms:
Low cusp teeth, modified cusp teeth.
Semi-Anatomical Teeth Indications:
- Well-formed ridges and fair ridges.
- When balanced occlusion to be achieved.
- In patient with mild jaw discrepancies.
Semi-Anatomical Teeth Advantages:
- Balanced occlusion can be easily obtained.
- Good chewing efficiency compared to nonanatomic teeth.
- Better esthetic compared to nonanatomic teeth.
- Shallow cuspal inclination generates less horizontal forces compared to anatomic teeth.
Semi-Anatomical Teeth Disadvantages:
- Poor esthetic compared to anatomic teeth.
- Lesser chewing efficiency compared to anatomic teeth.
Nonanatomic Teeth
Shape:
Cuspal angulation: 0°.
Synonyms:
Cusp less teeth, monoplane teeth, monoline, and zero degree teeth.
Nonanatomic Teeth Indications:
- Patient with poor ridge (severely resorbed ridge).
- Patient with poor neuromuscular control.
- Patient with jaw discrepancies.
- When crossbite tooth relation is indicated.
- Indicated to use for patient with uncoordinated closure and poor neuromuscular control, i.e. patients suffering from parkinsonism, dyskinesia, and stroke.
Nonanatomic Teeth Advantages:
- Quick arrangement of teeth.
- Less force transferred to residual alveolar ridge.
- Prevent destruction of tissue.
- Freedom of occlusal movements (from centric to eccentric position).
- Does not lock the mandible in one position.
- Permits the use of less time-consuming technique.
- Adapt easily to class II and class III jaw relations.
- More easily adjusted after changes in vertical and horizontal relations.
- Easier to arrange in crossbite.
Nonanatomic Teeth Disadvantages:
- Least chewing eficiency compared to semianatomic and anatomic teeth.
- Least esthetic compared to semi-anatomic and anatomic teeth.
- Difficult to arrange in balanced occlusion.
The Prosthetic Teeth Set
Prosthetic teeth are available as full set of 28 teeth including six anterior and eight posterior teeth (Total 14 teeth/arch) for each maxillary and mandibular arch. Some manufacturer provide anterior and posterior teeth separately also. Artificial teeth sets do not have third molars. They are attached on plastic card through wax. This plastic card is called as “tooth card” and wax used for this is “carding wax”.
Shape:
Prosthetic anterior teeth are usually available in square, tapered, and ovoid shapes.
Shade:
They are available in various shades like A1, A2, A3, A3.5, A4, B1, B2, B3, B4, C1, C2, C3, C4, D2, D3, D4, E1, F1, and F2.
Size:
Artificial teeth are available in various sizes. The size of teeth is designated by a number. Number describes the combined width of anterior teeth and A2 is the shade.
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