Investigate the hydrodynamic theory
N = 4 paid voluntary subjects planned for extraction due to periodontal disease.
- Before Treatment: sensitivity tested using EPT & cold by ethyl chloride to verify pain can be evoked.
- Tooth anesthetized w/ 3% mepivacaine. Small cavity prep made. Contraption to allow administration of positive and negative pressures. Pain intensity measured using finger span device (0-100).
- Hydrostatic pressures applied to (1) cavities in the presence of smear layer, (2) removal of smear layer with EDTA, (3) dentin tubules closed with 3% oxalic acid (topical application that forms calcium oxalate within dentinal tubules), and (4) removal of calcium oxalate by EDTA.
- Pain perception:
A.Presence of smear layer = no pain
B.Removal of smear layer = distinct sensation of pain
C.Presence of oxalic acid = no pain
D.Removal of oxalic acid = weak pain (prob some residual calcium oxalate is present)
- Faster changes in hydrostatic pressure evokes a higher pain intensity than slower rates of pressure changes.
Supports the hydrodynamic theory of dentin sensitivity