Anterior Teeth Selection in Dentistry

• Aesthetics and function are closely linked in dental practice.
• Anterior teeth aesthetics are important because they are visible when a person smiles, laughs, or talks.
• Posterior teeth function is a prime consideration because they are less visible.
• Selecting teeth is the dentist's responsibility, not the technician's.

Selection of Anterior Teeth

• Aesthetics plays a major role in selecting anterior teeth.
• Artificial teeth are manufactured in moulds.
• Patients require different shapes, sizes, and colors of artificial teeth.
• Selection criteria encompass tooth size (width, height), shape (form), color (shade), and material.

Pre-extraction Guides

• Pre-extraction guides are useful when available.
• Diagnostic casts provide a reliable guide in selecting tooth size and form.
• Photographs provide information on the width and form of the teeth.
• Radiographs provide useful information about the size and form of teeth.
• Extracted teeth are an excellent guide on size and form.

Determining Tooth Width

• Tooth size can be selected in proportion to the size of the face.
• The greatest bizygomatic width divided by 3.3 equals the approximate width of the six upper anterior teeth.
• The bizygomatic width divided by 16 gives the width of the upper central incisor.
• Marks on the maxillary occlusion rim corresponding to the corners of the mouth at rest correspond to the distal surface of the canine.
• A vertical line dropping from the ala of the nose may pass through middle of the canine.

Guide to the Vertical Height of the Tooth

• The patient smiles, exposing the occlusion rim; this level is marked.
• The incisogingival length of the mould selected should be greater than this so that the denture base does not show too much during smiling.
• Reduced interarch space would require the use of shorter teeth, whereas longer teeth would require a lot of grinding.

Form

• Face form (square, tapering, ovoid, square tapering) is considered.

Colour

• The shade is selected to harmonize with the patient's skin tones.
• Age, sex, and the color of the face influence shade selection.

Selection Criteria for Posterior Teeth

• Factors include color (shade), mesiodistal width, buccolingual width, occluogingival length (height), cuspal inclination/occlusal form, and material.

Mesiodistal Width

• Available space for maxillary teeth extends from the distal of the canine to the maxillary tuberosity.
• The teeth should not be placed beyond the tuberosity to avoid cheek biting and denture tipping.
• The available space for mandibular posterior teeth is from the distal of the canine to the beginning of the retromolar pad.

Buccolingual Width

• The buccolingual width of artificial teeth should be slightly less than that of natural teeth.
• A narrow occlusal table reduces the force needed to masticate.

Occluogingival Length (Height)

• The vertical height should correspond to the available interarch space.

Cuspal Inclination or Occlusal Form

• Cuspal inclination or occlusal form is defined as the angle between the palatal incline of the mesiobuccal cusp and the horizontal.

Classification of Posterior Teeth

• Based on cuspal morphology, posterior teeth may be classified as anatomic, semi-anatomic, or non-anatomic.
• Anatomic Teeth: Carved to simulate natural teeth e.g., 20-degree (semianatomic) and 33-degree teeth are examples.
• Well-formed ridges where good support and retention can be expected are indications for anatomical teeth.
• Advantages: Easier occlusion balancing, better chewing efficiency, and better aesthetics.
• Non-anatomic: Also known as flat, monoplane, cuspless, or zero-degree teeth; introduced to reduce lateral forces on the denture for stability.
• The lack cusps, but have some grooves/mechanical patterns to improve appearance and efficiency.
• Indications: Flat ridge cases, when balanced occlusion isn't planned, or in abnormal jaw relationships/difficulty recording centric relation.
• Disadvantages: They are not as esthetic like as the cusped teeth, difficult to balance requiring more effort to chew food.

Selection of Tooth Material

• Acrylic resin is commonly used due to its low cost and ease of use.
• Porcelain teeth are more esthetic and durable but technically more difficult to use.
• A combination of acrylic and porcelain teeth may be used.

Acrylic Resin Teeth

• Most widely used tooth material for complete dentures.
• Resin teeth do not damage or wear natural teeth.
• The teeth can be used when the opposing dentition consists of natural teeth, gold crowns, or inlays.
• They are easier to grind and fit when there is reduced interarch distance.
• Clasp contact may require grinding in removable partial dentures.
• Advantages: Inexpensive, easy to grind/adjust (especially in small interridge spaces), absorb occlusal stresses, do not wear opposing teeth/gold crowns, bond chemically, and are self-adjusting/polishing.
• Disadvantages: Wears easily, vertical dimension may be lost, and stains/discolors.

Porcelain Teeth

• Became more popular as acrylic teeth wear and stain.
• These teeth are mechanically retained with pins/channels and not chemically bonded.
• Indications: Sufficient interridge distance, well-formed ridge, and superior esthetics required.
• Contraindications: Poor mandibular ridges, opposing natural teeth (can cause chipping/wear), and opposed by gold crowns/bridges (causes significant wear).
• Advantages: Very aesthetic, doesn't stain/discolor easily, doesn't wear easily, maintains vertical dimension/masticating efficiency for years.
• Disadvantages: Clicking sound on impact, difficult to grind/adjust, requires adequate interridge distance, abrades/chips opposing teeth, doesn't chemically bond to the denture base.

Porcelain Acrylic Combination

• Various combinations are possible.
• Porcelain anteriors with resin posteriors should not be used together - resin posteriors wear faster, leading to anterior occlusal discrepancies and tissue destruction.