Resin Composite Restorations: Effect of Energy Density on Properties and Marginal Integrity
Abstract
Resin composite (Z250, 3M, St Paul, MN) was bonded in bulk with various degrees of cure into Class 2 preparations in extracted human molar teeth. Two control groups consisted of a highly-cured incrementally-placed group and a non-fatigued low- cure group. The restorations were subjected to 1000 thermal-cycles and 500,000 fatigue cycles from 18 to 85 Newtons using a stainless-steel sphere. Marginal integrity was evaluated using visual rating (ridit analysis) and microleakage. The degree of conversion had a significant effect on marginal defects but not on microleakage. Water had a significant dissolving effect on gingival margin integrity at very low degrees of conversion. Gingival marginal defects were maximized at 25% of maximum conversion and 3% of maximum hardness. There was no overall significant effect of thermal-mechanical stressing on marginal defects or microleakage. A recommended lower limit of gingival margin acceptability in a bulk-filled resin composite restoration was created by 80% of maximum conversion, 73% of maximum hardness and approximately 70% of maximum flexural strength and modulus in the gingival marginal area.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 30, 2002
- Accession Number
- ADA406636
Entities
People
- Kraig S. Vandewalle
Organizations
- Oregon Health & Science University