Abstract
Objectives: Application of irritants on the exposed dentine of the incisors has been shown to produce aversive behaviour in awake rats. This study aims to demonstrate that the observed aversion is due to the infiltration of irritants through the dentinal tubules and the activation of capsaicin sensitive fibres in the tooth pulp. Methods: Different groups of rats were subjected, under anaesthesia, to cutting of the distal 2mm of their lower incisors and the fixation of an artificial crown that allows the application of 10-15μl of solution. Several procedures were followed to prevent the action of the irritants including occlusion of the dentinal tubules, local application of lidocaine, selective ablation of the capsaicin sensitive primary afferents (CSPA) or incisor pulpectomy; the reactions to intradental application of either capsaicin (1%) or formalin (2.5%) were tested using a newly designed behavioural score. Results: Occlusion of dentinal tubules produced significant attenuation of the nociceptive behaviour induced by dentinal application of either capsaicin or formalin. Similar results were observed following either local block with lidocaine (2%), selective ablation of capsaicin sensitive afferents or total denervation by pulpectomy. Conclusions: The present results confirm the hypothesis of infiltration of irritants to the incisor pulp through the dentinal tubules and suggest that the reported inflammatory reaction and hyperalgesia are mediated, to a large extent, by capsaicin sensitive primary afferents.
Original language | English (US) |
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Pages (from-to) | 457-468 |
Number of pages | 12 |
Journal | Archives of Oral Biology |
Volume | 49 |
Issue number | 6 |
DOIs | |
State | Published - Jun 2004 |
Funding
The authors wish to thank Mrs. Sawsan Sharrouf and Messrs Riad Maalouf and Bassem Najm for their technical assistance. This research was supported by a grant from the Lebanese National Council for Scientific Research.
Keywords
- Dental pain
- Dentine desensitisers
- Pain test
- Sensory afferents
- Tooth inflammation
ASJC Scopus subject areas
- General Dentistry
- Cell Biology
- Otorhinolaryngology