Effect of nitric oxide synthase inhibitor (L-NAME) on substance P-induced vasodilatation in the dental pulp.

AIM: To investigate the vasodilator mechanisms of pulpal vessels, especially the involvement of nitric oxide (NO), during pulpal inflammation. METHODOLOGY: Eleven cats were prepared for intra-arterial administration of test agents through a lingual artery. The pulpal blood flow was measured by laser Doppler flowmetry from ipsilateral mandibular canine teeth. By using the NO synthase (NOS) inhibitor N(G)-nitro L-arginine methyl ester (L-NAME), the effects of L-NAME on various vasodilators, such as Substance P (SP)-, calcitonin-gene related peptide (CGRP)-, and papaverine-induced vasodilatation, were compared in vivo in 11 feline dental pulps. RESULTS: L-NAME pretreatment potentiates SP-induced vasodilatation for a duration of approximately 5 h. The increase of pulpal blood flow ranged from 91.47 to 109.91%, which was significantly different from SP injection alone (48.79%, P < 0.05). Other vasodilators such as CGRP and papaverine did not respond to L-NAME pretreatment. CONCLUSIONS: This study demonstrates that NOS inhibitor L-NAME administration alone has insignificant effects on pulpal blood flow, although L-NAME pretreatment can potentiate SP-induced vasodilatation, probably via increased activity in the enzyme guanylate cyclase. CGRP and papaverine did not respond to L-NAME pretreatment, indicating that they are not mediated via an endothelium-dependent mechanism.

A six-canal maxillary first molar: case report.

AIM: The aim of this case report is to describe an unusual six-canal maxillary first molar tooth. CASE REPORT: The maxillary left first molar of a young African-American male was treated as an emergency at the first visit. At the second visit, the five canals (MB1 and 2, Pal1 and 2 and DB) were easily identified at high magnification of 16-25 under an operating microscope. The canals were then instrumented and filled using the Microseal technique. A careful radiographic examination of the final fill indicated that there was a third canal in the palatal root as suggested by a slight extrusion of the filling material between the two canals. At the third visit, the fillings of the palatal canals were removed and the apical 4mm was re-examined. The existence of a third palatal canal exiting between the two apices was verified and subsequently instrumented and obturated. KEY LEARNING POINTS: It should be assumed that all molar teeth have more than the traditionally expected three canals. The location of root canals should be identified at high magnification under the microscope. Careful radiographic re-examination of the fillings should be done in order to identify possibly missed canals.

A supernumerary tooth fused to the facial surface of a maxillary permanent central incisor: case report.

A case of a supernumerary tooth fused to the facial surface of a maxillary permanent central incisor is reported. Root canal therapy on the maxillary central incisor was performed due to pulpal communication between the supernumerary tooth and the maxillary central incisor after removing the supernumerary tooth structure. The communication was sealed with mineral trioxide aggregate. The difference between fusion and gemination is discussed.

Is there a best retrograde filling material?

Operating microscopes and ultrasonic instruments have been used in root end filling procedures. The concepts, techniques, and materials for root end filling have been evolving. After eradicating or minimizing the irritants in the root canal system, the root end cavity has to be filled in a practical and convenient way. Super EBA seems to have more advantages. Some other potential root end filling materials and techniques are also discussed.