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Diss Factsheets

Toxicological information

Additional toxicological data

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Administrative data

Endpoint:
additional toxicological information
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: Tested material CRCD consisted of 15-25 % Ca-hydroxide only.

Data source

Referenceopen allclose all

Reference Type:
secondary source
Title:
Neurotoxic effect of two root canal sealers with calcium hydroxide on rat phrenic nerve in vitro
Author:
Boiesen J and Brodin P
Year:
1991
Bibliographic source:
Endod. Dent. Traumatol. 7: 242-245
Reference Type:
secondary source
Title:
Neurotoxic effect of two root canal sealers with calcium hydroxide on rat phrenic nerve in vitro
Author:
Boiesen J and Brodin P
Year:
1991
Bibliographic source:
cited in: Consensus Report for Calcium Oxide and Calcium Hydroxide, February 24, 1999

Materials and methods

Type of study / information:
in vitro treatment of rat phrenic nerves

Test material

Constituent 1
Chemical structure
Reference substance name:
Calcium dihydroxide
EC Number:
215-137-3
EC Name:
Calcium dihydroxide
Cas Number:
1305-62-0
Molecular formula:
CaH2O2
IUPAC Name:
calcium dihydroxide
Details on test material:
Test material CRCS consisted of 15-25% Calcium hydroxide and 30% Zinc oxide

Results and discussion

Any other information on results incl. tables

Root canal sealers placed into contact with the inferior alveolar nerve can cause paraesthesia in the area innervated by this nerve. The paraesthesia is due to neurotoxic effects of the sealers. In this study we examined the effect on nerve conduction in vitro of two calcium hydroxide-containing root canal sealers, Sealapex and CRCS. An isolated rat phrenic nerve was placed between two suction electrodes in a bath containing Tyrode solution. The sealers were brought into contact with the nerve, and the evoked compound action potentials (cAP) were recorded before and after contact with the materials. Both Sealapex and CRCS induced a fast and complete inhibition of the cAP in this model. The degree of reversibility of the inhibition varied from experiment to experiment. Both materials exhibited reversible and irreversible block of the nerve conduction after 90s and 5 min exposure. However, after 30 min of contact, the conduction of the cAP was irreversibly blocked for both materials.

Applicant's summary and conclusion