Dental pain and cyclooxygenase activity in human teeth with normal and inflamed pulps
1
Issued Date
2023
Copyright Date
2003
Language
eng
File Type
application/pdf
No. of Pages/File Size
xvii, 139 leaves : ill.
ISBN
9740438725
Access Rights
restricted access
Rights Holder(s)
Mahidol University
Bibliographic Citation
Thesis (Ph.D. (Oral Biology))--Mahidol University, 2003
Suggested Citation
Warungkana Chidchuangchai Dental pain and cyclooxygenase activity in human teeth with normal and inflamed pulps. Thesis (Ph.D. (Oral Biology))--Mahidol University, 2003. Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/88905
Title
Dental pain and cyclooxygenase activity in human teeth with normal and inflamed pulps
Alternative Title(s)
การปวดฟันและการทำงานของเอ็นไซม์ Cyclooxygenase ในฟันมนุษย์ที่ปกติและที่มีการอักเสบของเนื้อเยื่อในโพรงประสาทฟัน
Author(s)
Abstract
The purposes of this series of experiments are to compare the pain sensation produced by cold stimulation of exposed dentine under different conditions in vivo and the fluid flow through dentine under similar conditions in vitro and to investigate the effects of pulpal inflammation on pulpal fluid prostaglandin E2 (PGE2) levels, pulpal blood flow, sensory threshold, and pain sensation evoked by thermal stimulation of dentine in human subjects. The experiments were carried out on 44 healthy premolar teeth in 27 human subjects (aged 16-30 years). The teeth were scheduled for extraction as part of orthodontic treatment. The series I experiment was done on 24 teeth from 17 subjects. Dentine was exposed at the tip of the buccal cusp by cutting a cavity (diam. 3 mm, depth 3 mm) with a diamond bur in an air-rotor handpiece under a constant stream of water. Cold stimuli were applied by placing the tip of an ice stick in the cavity for five seconds. The subject indicated the intensity of any pain produced by placing a mark on a visual analog scale (VAS). This method of testing dentine sensitivity was repeated after etching the dentine with 35% phosphoric acid for 30 seconds and after treating the etched dentine with potassium tetraoxalate for two minutes. Fluid flow through dentine produced by the cold stimuli under similar conditions was recorded in the teeth after they had been extracted. The series II experiment was done on 20 teeth from 10 subjects. Laser Doppler records of pulpal blood flow were obtained after isolating the teeth with opaque black rubber dam and sensory thresholds were determined with a monopolar electrical pulp tester. Dentine was exposed at the tip of the buccal cusp (diam. 3 mm, depth 3 mm) and the smear layer removed by acid etching (35% phosphoric acid for 30 seconds). Samples on dentinal fluid were collected by placing 10 µl phosphate-buffered saline in the cavity for five minutes. The pain evoked by thermal stimulation (ice stick, water at 10 and 60°C) of the exposed dentine for five seconds was scored. The cavity was then filled with either gutta percha alone (GP) or, on the contralateral side, GP sealed with glass ionomer material (GI). After one week, the fillings were removed, the cavities cleaned with distilled water, and the measurements and stimuli repeated. The teeth were extracted and fractured longitudinally. Pulpal tissue fluid was collected from the buccal horn. PGE2 levels in dentinal and pulpal fluid were determined using enzyme immunoassay. Results in the series I experiment revealed that the mean VAS score produced by the ice before etching was 21.25 mm (SD 19.46 mm). After etching, the mean VAS score increased significantly to 85.42±15.60 mm, and after oxalate treatment it decreased significantly to 8.54±13.31 mm (P<0.01, One-way RM ANOVA and Tukey test). The mean rates of fluid flow through dentine induced by cold stimulation before etching, after etching and after oxalate treatment were 2.15±1.02, 1.55±0.84, and 2.29±1.28 nL/s/mm2 respectively, indicating the mean rate after etching to be significantly different than the other two rates (P<0.05). Results in the series II experiment revealed that treatment with GP+GI had no significant effects on mean pulpal blood flow, mean VAS scores, and mean sensory threshold. In contrast, treatment with GP alone increased both mean pulpal blood flow and mean VAS scores but decreased mean sensory threshold. PGE2 levels were significantly higher after filling with GP than GP+GI (in dentinal fluid: 1.32±1.26 and 0.67±0.56 ng/ml; in pulpal fluid: 424.44±377.06 and 150.38±164.70 ng/ml, respectively; p<0.05, Student's t-test). This marks the first time that PGE2 level in dentinal fluid has been measured. Conclusion: Sensory transduction of cold stimuli in human teeth does not depend only on a hydrodynamic mechanism. The unsealed GP filling caused an increase in the PGE2 levels of dentinal and pulpal fluid, a decrease in sensory threshold to electrical stimulation, pulpal vasodilatation and hyperalgesia of dentine to thermal stimulation. This study was supported from the Thailand Research Fund through the Royal Golden Jubilee Ph.D. Program.
Degree Name
Doctor of Philosophy
Degree Level
Doctoral Degree
Degree Department
Faculty of Dentistry
Degree Discipline
Oral Biology
Degree Grantor(s)
Mahidol University