Summary This report describes the clinical presentation and histopathological findings of two horses with equine odontoclastic tooth resorption and hypercementosis (EOTRH) affecting all cheek teeth. Equine odontoclastic tooth resorption and hypercementosis is a well documented condition known to affect the incisors, canines and occasionally the premolars in horses. At this time there have been no documented cases of EORTH affecting all cheek teeth described in the peer reviewed literature. This paper documents the first reported cases of EOTRH affecting the cheek teeth in one horse in the United States and one from Germany.

In this paper, various techniques for determining the age-and season-of-death of wild horse specimens are systematically compared using a sample derived from the Neolithic site of Bad Buchau-Dullenried, Germany. Tooth eruption and wear, crown height, manual optical analysis of dental cementum, line histogram analysis of dental cementum, and a new automated digital technique for analysing dental cementum are employed. Each tooth was measured, thin-sectioned, digitally photographed under microscopy, and the cementum layers analysed. The goal is to determine which technique is the most efficient (in terms of time and resources) and accuracy (in terms of age-and season-of-death) for analysts to employ. The data demonstrate that there is substantial variation between the techniques for determining the age-and season-of-death of individuals, and even between teeth of the same specimen. The results demonstrate that the digital automated technique has an advantage over conventional cementum increment counting in terms of reduced subjectivity, efficiency and accuracy for the identification of season-and age-of-death.

Summary Shear mouth is a rare and poorly described dental condition observed in horses. This report outlines 2 cases of unilateral shear mouth with ipsilateral painful dental disease. Both cases are young horses diagnosed with idiopathic 409 cheek tooth fractures associated with shear angles on the 100 and 400 cheek teeth rows. Corrective odontoplasty was performed in both cases to correct the cheek tooth occlusal surface angle following exodontia of the diseased molars.

The skin surface biopsy technique has been used to investigate the erythrasma organismin situin the stratum corneum in 11 patients. Staining by PAS and Gram stain showed the presence of a large number of organisms arranged haphazardly in some areas and in microcolonies in others. With the scanning electron microscope it was possible to see that smooth filamentous chains of microorganisms had penetrated horn cells and caused disturbance of the surface structure of these cells.Enzyme histochemical tests showed that the erythrasma microorganism possessed a strong reactivity for NAD diaphorase and other mitochondrial enzymes. The reactivity was focal confirming a complex subcellular organization of organelles.It is suggested that the erythrasma microorganism secretes a mucopolysaccharide sheath in some circumstances.

A technique is described which measures the penetration of substances through the stratum corneum (SC) and the distribution of elements in this structure employing scanning electron microscopy and energy dispersive analysis. Preliminary observations show that the normal SC shows a concentration gradient of potassium, high in the surface layers and lowest deeper down whereas the reverse is true for phosphorus. It has been shown that sulphur rapidly tranverses the SC and seems to penetrate through all parts of the horny layer whereas lead and zinc do not easily enter this structure.