Resin Composites in Dentistry: Uses, Pros, and Cons

Posted on Jan 24, 2025 in Biology

Advantages of Resin Composites

Resin composites offer several benefits in dental applications:

  • Superior aesthetic quality: They closely mimic the natural appearance of teeth.
  • Satisfactory physical and mechanical properties: They possess adequate strength, toughness, and surface hardness.
  • Conservation and reinforcement of tooth structure: When combined with adhesives, they help preserve and strengthen the remaining tooth.
  • Low thermal conductivity: They do not transmit thermal shocks to the pulp, enhancing patient comfort.
  • Easy to repair: Damaged composite restorations can be readily repaired.

Disadvantages of Resin Composites

Despite their advantages, resin composites have some limitations:

  1. Questionable adaptation to tooth structure: High polymerization shrinkage can compromise the seal between the restoration and the tooth.
  2. Potential for occlusal wear: They may exhibit wear in areas of high occlusal stress.
  3. Hydrolytic instability: They can be susceptible to water sorption and hydrolysis by environmental acids.
  4. High technique sensitivity: Proper isolation and meticulous technique are crucial, especially with adhesive systems.
  5. Lack of anticariogenic potential: Conventional composites do not release fluoride to prevent caries.

Indications for Resin Composites

Resin composites are suitable for a wide range of dental procedures:

  1. All classes of cavity preparations.
  2. Aesthetic enhancement procedures, including correction of tooth form and contour.
  3. Pit and fissure sealants and conservative restorations.
  4. Foundation or core build-up material under crowns and bridges.
  5. Cementation of indirect aesthetic restorations.
  6. Repair of restorations, periodontal splinting, and bonding of orthodontic brackets.

Contraindications for Resin Composites

Resin composites may not be ideal for all patients:

  1. Patients with poor oral hygiene and a high caries index.
  2. Cases where proper isolation of the operating site from oral fluids is difficult.
  3. Patients with heavy occlusal stresses due to unfavorable occlusion or bruxism.

Steps for Applying Resin Composite Restorations

  1. Selection of resin composite type.
  2. Shade selection.
  3. Isolation of the operatory field.
  4. Application of liner/base (if needed).
  5. Matricing and wedging.
  6. Application of adhesive system.
  7. Packing and curing of composite.
  8. Finishing and polishing.

Matrix and Wedge Choice for Posterior Proximal Restorations

For posterior proximal restorations, the choice of matrix and wedge is typically:

  • A sectional matrix and wooden wedges.

Other options include:

  • A pre-contoured Mylar matrix and transparent wedges.
  • A metallic matrix in a Tofflemire retainer and wooden wedges.

Dry Bonding Technique

In the dry bonding technique, the cavity preparation is dried with short blasts of intermittent oil-free air until a chalky white appearance of the enamel is observed.

Wet Bonding Technique

In the wet bonding technique, excess moisture following rinsing is blotted with a cotton pellet or a micro-sponge until no moisture can be blotted anymore. Dentin should appear shiny and hydrated.

Advantages of Visible Light-Cured Over Chemical-Cured Composites

  1. Command setting: Dentists have better control over the curing process.
  2. No incorporation of air bubbles: This leads to a more homogeneous restoration.
  3. Improved color stability: Light-cured composites tend to maintain their color better over time.
  4. Better control over polymerization shrinkage: The direction and amount of shrinkage can be managed more effectively.

Advantages of Incremental Packing Technique

  1. Reduced total polymerization shrinkage: Each increment compensates for the shrinkage of the previous one.
  2. Controlled direction of polymerization shrinkage: The light-curing tip can be directed to minimize stress on the tooth-restoration interface.