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Influence of curing tip distance on composite Knoop hardness values
L C Sobrinho1, A A de Lima, S Consani
1Area Materiais Dentários, Faculdade de Odontologia de Piracicaba, UNICAMP, Piracicaba, SP, Brasil. sobrinho@fop.unicamp.br
Brazilian Dental Journal
|February 24, 2001
Summary
Curing light distance significantly impacts dental composite hardness. Z100 composite showed decreased Knoop hardness with increased distance, while Silux Plus hardness was less affected, though deeper layers were softer. Z100 demonstrated superior hardness overall.
Area of Science:
- Dental Materials Science
- Polymer Chemistry
- Biomaterials Engineering
Background:
- Dental composites are widely used restorative materials.
- Light-curing is essential for composite polymerization.
- Curing light parameters, including distance, can influence material properties.
Purpose of the Study:
- To investigate the effect of curing tip distance on the Knoop hardness of Z100 and Silux Plus dental composites.
- To evaluate hardness at various depths under different curing tip distances.
- To compare the performance of Z100 and Silux Plus composites concerning curing distance effects.
Main Methods:
- Two dental composites (Z100, Silux Plus) were polymerized at tip distances of 0 mm, 6 mm, and 12 mm using a standardized curing unit.
- Specimens were stored for 24 hours at 37°C.
- Knoop hardness was measured at different depths using a microhardness tester with a 50g load for 30 seconds.
- Data were analyzed using ANOVA and Tukey's test.
Main Results:
- For Z100 composite, Knoop hardness decreased significantly as curing tip distance increased.
- For Silux Plus, increased curing tip distance did not significantly alter overall Knoop hardness, but deeper layers showed reduced hardness at 6 mm and 12 mm.
- Z100 exhibited statistically superior Knoop hardness compared to Silux Plus across all tested distances and depths.
Conclusions:
- Curing tip distance is a critical factor affecting the Knoop hardness of Z100 composite.
- Silux Plus shows less sensitivity to curing distance, but depth-dependent hardness variations occur.
- Z100 is a harder composite than Silux Plus, irrespective of curing tip distance and depth.