Dental pulp is a loose, mesenchymal tissue almost entirely enclosed in the dentin. It consists of cells, ground substance, and neural and vascular supplies. Damage to the dental pulp by mechanical, chemical, thermal, and microbial irritants can provoke various types of inflammatory response. Pulpal inflammation leads to the tissue degradation, which is mediated in part by Matrix metalloproteinase leads to accelerate extracellular matrix degradation with pathological pathway. We have now investigated the induction of MMPs and inflammatory cytokines by Lipopolysaccharide (LPS) control of inflammatory mediators by peroxisome proliferator-activated receptors (PPARs).

Human dental pulp cells exposed to various concentrations of LPS (1-10 µg/ml) revealed elevated levels of MMP-2 and MMP-9 at 24 hrs of culture. LPS also stimulated the production of ICAM-1, VCAM-1, IL-1β, and TNF-α. Adenovirus PPARγ (Ad/PPARγ) and PPARγ agonist rosiglitazone reduced the synthesis of MMPs, adhesion molecules and pro-inflammatory cytokines. The inhibitory effect of Ad/PPARγ was higher than that of PPARγ agonist.

These result offer new insights in regard to the anti-inflammatory potential of PPARγ in human dental pulp cell.

This study compared the dentin adhesion to composite resin according to air-dry, blot dry, application of rewetting agent on air-dry or blot dry dentin surface by microleakag test and SEM observation.

For microleakage test, class V cavity preparations with dentinal margins were prepared on both buccal and lingual surfaces of 40 extracted human molars. For SEM observation, occlusal dentin of 20 extracted human molars were exposed.

After etched the dentin, prepared teeth were randomly divided into four groups;

D group: air dry for 10-15 sec., B group: blot dry with moist cotton pellet, D-R group: air dry and rewet with Aqua-Prep F for 20 sec., B-R group: blot dry and rewet with Aqua-Prep F for 20 sec.

Treated cavities and surfaces were filled or constructed using One-Step adhesives and Aelitefil composite resins. Specimens were stored in distilled water for 24 hours. For microleakage test, the specimens were thermocycled and soaked into 2% methylene blue. The specimens were sectioned longitudinally and evaluated for microleakage under steromicroscope. The data were statistically analysed by Kruskal-Wallis Test, Mann-Whitney and Wilcoxon signed ranked tests. For SEM observation, the specimens were bisectioned mesiodiatally. After decalcified and deproteinized, specimens were observed under SEM.

The results of this study were as follows;

1. The microleakges on dentinal margin were the highest in D group compared with B group, D-R group, and B-R group(p<0.05). But there was no significant difference between B group, D-R group and B-R group.

2. D group showed gap and a few resin tags between dentin and composite resin.

3. B group, D-R group, and B-R groups showed close adaptation between dentin and composite resin. It showed that resin rags in B group were numerous and long, in D-R group were few and short, in B-R group were numerous and short or long.

4. Adhesive layer showed in D-R group (10 µm) and B-R group (3 µm)

In conclusion, use of rewetting agent to dry dentin was efficient to dentin adhesion, also it did not provide reverse effect on blot dry dentin.