The Relationship between the Cavity Form and the Pulp Chamber of the Deciduous Molars

Abstract

  The purpose of this study was to investigate the relationship between the cavity preparation form and the pulp chamber of deciduous molars.

  The materials were nondecalcified 323 serially ground specimens which were prepared mesiodistally and buccolingually from 40 extracted deciduous molars. PARAREROMETER PARAFIX 78 (MORITA COMPANY) was modified as a standard cutting instrument for cavity preparation. With this standard cutting instrument, Class Ⅰ (G.V.BLACK's classification) cavities were prepared. The depth of the cavity was standarized to 0.5mm from the enamel-dentin junction to the cavity floor at the center of the central groove and the center of the central fossa.

  The results showed that the cavity floor did not lie in the enamel but in the dentin in all of the observation areas and the depth of the cavity tended to be deeper at the mesial and distal sides than at the center of the central groove and at the center of the central fossa. The distance from the cavity to the pulp chamber tended to be shorter at the lingual side than at the buccal side, and also tended to be shorter at the mesial side than at the distal side.

  It was shortest at the mesio-buccal side. The minimum distance from the cavity to the pulp chamber was 0.37mm at the buccal wall of the mesial marginal ridge in the upper first deciduous molar, and 0.66mm at the distal wall of the buccal groove in the upper second deciduous molar, and 0.48mm at the buccal wall of the mesialmarginal ridge, 0.50mm at the distal torigonid ridge and 0.51mm at he center of the distal torigonid ridge in the lower first deciduous molar, and 0.67～0.74mm at the mesial marginal ridge and at the mesio-buccal groove (0.96～0.97mm) in the lower second deciduous molar.