The Prevalence of Occlusal Lesions in Equine Cheek Teeth from Horses with Clinical Signs of Apical Pulpitis Compared to Controls

Aims 

To assess prevalence and severity of secondary dentinal defects and infundibular caries observed on occlusal examination of teeth from horses showing clinical signs of apical pulpitis compared to normal controls.

Methods

Occlusal surfaces of 23 mandibular and 21 maxillary cheek teeth, extracted from horses with clinical signs of apical pulpitis attributed to those teeth, were examined using a fine probe. Occlusal surfaces of 50 mandibular and 40 maxillary cheek teeth from cadavers with no known history of dental disease were assessed as controls. Triadan positions and eruption ages were matched as closely as possible. Occlusal secondary dentinal defects were identified and graded. Maxillary infundibular caries was identified and graded using the modified Honma system. The prevalence of lesions in clinically affected and control teeth was compared using Fisher’s exact test.

Results

Secondary dentinal defects were significantly over-represented in diseased teeth (P<0.001). Thirteen out of 23 diseased mandibular teeth had defects compared to none of the controls (0/50). As a test for apical pulpitis in mandibular teeth, assessment of secondary dentinal defects had sensitivity of 56.5% and specificity of 100%. Eleven out of 21 diseased maxillary teeth had defects compared to 1/40 controls (sensitivity 52.3%, specificity 97.5%). There was no significant difference (P=1) in prevalence of infundibular caries in diseased teeth (11/21) compared to controls (21/40). However infundibular caries of Honma grade ≥ 2 was significantly over-represented (P=0.005) in the diseased teeth (6/21) compared to controls (1/40). Such lesions were always in rostral infundibula.

Conclusions and Practical Significance

These results confirm that careful examination of occlusal secondary dentine is a vital component in investigation of suspected apical pulpitis in equine cheek teeth. Results suggest that infundibular caries is a poor indicator of apical disease. However infundibular caries of Honma grade ≥ 2 may be clinically significant. [...]