Scanning electron microscopy of pulp cavity dentin in dogs

Dentin morphology and tubule diameter and density of peripulpal dentin were evaluated in 36 teeth from 12 adult dogs, aged between 2.5 and 13-years. The right maxillary canine and third premolar and right mandibular first molar teeth were extracted from euthanized dogs. The teeth were prepared and photomicrographs (n=108) were taken of the radicular and coronal dentin. Dentinal tubule density (tubules/mm2) was determined and tubular diameter and luminal area were measured in 3240 randomly chosen tubules using measurement software. Results from group 1 dogs (< 7-years-old) were compared with group 2 dogs (> 7-years-old). The majority of dentinal tubules were round or oval in shape and had uniform distribution at the radicular coronal third, and coronal levels. Dentin surfaces showed morphological differences at different levels of the tooth. Group 1 dentinal tubule diameter (1.87 +/- 0.44 microm) and area (1.91 +/- 0.83 microm2) were significantly different compared with Group 2 dentinal tubule diameter (1.53 +/- 0.39 microm) and area (1.22 +/- 0.50 microm2). There was no significant difference in tubular density between groups 1 (74,692 +/- 25,991 tubules/mm2) and 2 (72,938 +/- 24,646 tubules/mm2). Site-specific differences were observed in the pulp cavity dentin in the same tooth. These results provide a reference for future research in dogs or where dogs are used as a model for investigations in human dentistry.