Conventional and microfilled composite resins. Part II. Chip fractures

Area of Science:

• Dental Materials Science
• Restorative Dentistry

Background:

• Microfilled composite resins present unique challenges in clinical practice.
• Chip fractures are a notable disadvantage compared to conventional composite resins.

Purpose of the Study:

• To analyze the causes and implications of chip fractures in microfilled composite resins.
• To define appropriate clinical indications and contraindications for microfilled composite resins.

Main Methods:

• Comparative analysis of material properties (thermal expansion, water sorption, polymerization shrinkage, tensile strength).
• Review of clinical performance data regarding cohesive and adhesive failures.

Main Results:

• Microfilled resins exhibit higher rates of cohesive and adhesive chip fractures (3-4x) versus conventional resins.
• Properties contributing to fractures include higher thermal expansion, water sorption, polymerization shrinkage, and lower tensile strength.

Conclusions:

• Microfilled composite resins are indicated for esthetic purposes and limited Class I restorations where esthetics are critical.
• Contraindicated for Class IV and stress-bearing restorations; require acid-etching and intermediate bonding.
• Suitable for resurfacing, veneering, and treating cervical erosion due to smooth finish and high luster.