Chaiwat Maneenut, DDS, MDSc,(a) Toru Nikaido, DDS, PhD,(b) Richard M. Foxton, BDS, PhD,(c) and Junji Tagami, DDS, PhD(b),(d)
(a)Department of Operative Dentistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand, (b)Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, (c)Division of Conservative Dentistry, GKT Dental Institute, London, United Kingdom, and (d)Center of Excellence Program for Frontier Research on Molecular Destruction and Reconstruction of Tooth and Bone, Tokyo Medical and Dental University, Tokyo, Japan
Purpose: To evaluate nanohardness of caries-affected dentin adjacent to conventional and resin-modified glass ionomer cements.
Materials and Methods: Dentin caries was removed from the occlusal surfaces of human molars. Teeth were cut mesio-distally through the middle of prepared cavities to get two halves. One half was filled with the tested material, either Fuji IX GP or Fuji II LC, while the other half was unfilled and used as a negative control (n=7). After 1, 7 and 30 days of restoration, nanohardness was measured on intertubular dentin at 20, 40, 60, 80 and 100 μm from the pulpal margin. Mean nanohardness` at each distance of each period were compared using analysis of variance (ANOVA) and Fisher’s least significant difference (LSD) multiple comparison tests at significant level of 5%.
Results: Nanohardness of caries-affected dentin adjacent to both materials increased after restoration for seven days. Significant increases were observed after 30 days of restoration. Nanohardness change of caries-affected dentin adjacent to Fuji IX GP was more than that adjacent to Fuji II LC.
Conclusion: The nanohardness of caries-affected dentin adjacent to conventional and resin-modified glass ionomer cements increased after seven days of restoration.
(Int Chin J Dent 2003; 3: 122-130.)
Clinical Significance: Application of glass ionomer cements on caries-affected dentin can increase hardness of such dentin.
Key Words: caries-affected dentin, glass ionomer cement, nanohardness.