Root canal morphology was evaluated in 72 maxillary fourth premolar and 59 mandibular first molar teeth. An apical delta was present in all roots (n = 334). The apical delta represented approximately 12-18% of the total root length for all roots. Non-apical ramifications from the main canal were observed in 25.1% of roots. Secondary canal(s) were present in 20.6% of roots, while lateral canal(s) were present in 6.9% of roots. The distal root of the maxillary fourth premolar had the highest incidence (47.2%) of non-apical ramifications. Overall, 68.0 and 20.4% of maxillary fourth premolar and mandibular first molar teeth had non-apical ramifications, respectively. The prevalence and location of non-apical ramifications may influence clinical decision making when performing endodontic therapy.

The furcation region morphology was evaluated in 103 mature feline carnassial teeth (54 maxillary fourth premolar and 49 mandibular first molar teeth). Patent furcation canals were present in 27.2% of teeth. No significant difference (p = 0.88) in distribution of this anatomical variation was found between maxillary fourth premolar and mandibular first molar teeth. The mean width of these furcation canals was 104.0 microns with two-thirds of the canals having a buccal orientation. The presence of furcation canals could be a factor in the etiopathogenesis of feline dental resorptive lesions, as well as a characteristic to be considered in the diagnosis, prognosis, and treatment of endodontic or periodontic-endodontic lesions in cat teeth.

A 4-year-old female DSH cat was presented with a chronic history of a periorbital fistula (Fig. 1). During the previous 3-months, the lesion had been treated with systemic antimicrobials and antimycotic agents. The lesion Payment (US FUNDS ONLY) made out to PSP Communications, Inc.

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.

External and internal ultramicroscopic characteristics of the tooth root apex in dogs were determined. Thirty teeth (16 maxillary fourth premolars, 7 mandibular first molars, and 7 maxillary canines) were examined. Teeth were obtained from 9 dogs with a total of 59 roots evaluated. Roots were sectioned perpendicular to the long axis (41), 3 to 7-mm from the apex, and others were sectioned longitudinally (18). Specimens were observed using scanning electron microscopy. The major diameter of 1,700 foramina and the depth of apical deltas were measured. The shape of the apex varied from round to elliptical and round-elliptical, with a regular or irregular surface. All root apices had many foramina, most (85.44 %) with a diameter < 50-μm. The maximum foramen diameter was 234.19-μm. Great variation was observed in the size of the apical foramina. The internal aspect of the cementum at the apical level showed a “sieved plug”. The extension of the cementum within the root canal forming the apical delta measured 2 ± 0.4-mm.