288 DENTAL TARTAR. 



oftenest seen on the outer surface of the crown, turned towards 

 the cheek. It commences in the neighbourhood of the gums, and 

 gradually spreads upwards and downwards. Incisors and molars 

 are alike affected, the latter more frequently, but in horses the tushes 

 are the commonest seat. 



A pale yellow or greyish-brown chalk-like substance, rather 

 rough on the surface, covers that portion of the crown lying nearest 

 the gum. In the dog it stands out clearly on the shining white 

 surface of the tooth. Hertwig states that in goats tartar sometimes 

 appears black and metallic from admixture of oxide of iron. 



The deposit spreading may completely encapsule the crown above ; 

 while, as it increases below, it produces atrophy and recession of the 

 gum. Here lies the chief danger. As soon as the alveolus is exposed 

 it becomes inflamed by the fluids of the mouth. This is by far the 

 commonest cause of alveolar periostitis in dogs, and is especially 

 frequent in house dogs. 



The food decomposes in the alveolus, producing a grey slimy 

 material which can be partly squeezed out by pressure, and has a 

 peculiarly penetrating odour. The' gum is bluish-red and swollen, 

 bleeds easily, and is sometimes studded with little abscesses. The 

 disease has hence been named " scurvy," whilst, on account of the 

 offensive smell, it is also known as " mouth rot." 



The black coloration, produced by feeding on husks and brewers' 

 grains, must not be confounded with tartar. Its exact nature is 

 not known, but it affects only the surface of the crown. The 

 significance of tartar lies in the possibility of its exciting alveolar 

 disease. Provided the alveolus is healthy, recovery follows removal 

 of the deposit ; but teeth already much loosened can only be extracted. 

 The smell is often so offensive that the dog cannot be tolerated in 

 the house. 



Treatment. The deposit is removed with teeth scalers or similar 

 instruments (Fig. 286), avoiding injury of the gum or alveolus. To 

 get rid of the incrustation, the teeth may be regularly cleansed for 

 some time with pumice or citric acid. Sporting dogs being the usual 

 patients, these measures can be carried out thoroughly. The gum 

 is protected by placing the instrument close to it, and scraping 

 towards the table of the tooth. Immediately the tooth becomes 

 loose, extraction is the only resource. The fee tor of the mouth can 

 be removed by brushing the teeth with a solution of potassium per- 

 manganate. 



