NOTES ON DENTISTRY. 537 



1069. Caries of the Teeth. 



Caries or decay consists in the destruction by progressive softening 

 and wearing away of the hard tissues of the tooth, originating always from 

 without and usually affording a cavity for the lodgment of saliva or 

 food. It usually occurs in the molars and generally at their crowns. 



Caries is due to loss of vitality in the structure known as Dentine, 

 which renders it unable to resist the chemical action of the saliva. 

 Caries may also arise from injuries or from masticating pebbles in the 

 food ; but more frequently from constitutional causes. 



Sharp Edges of Molars. 



In aged horses, especially where the inferior jaw-bone is proportionally 

 narrower than the upper, the outer edges of molar teeth become ex- 

 tremely sharp, and by their needle-like points so seriously lacerate the 

 cheeks as to hinder mastication. Thousands of these cases exist all 

 unsuspected by owners or attendants, and it is in the periodical reduc- 

 tion of these growths that the equine dentist is especially needed. In- 

 deed, it is necessary in all unaccountable cases of loss of condition to 

 examine the molar teeth. 



Dental Cough. 



The sound of Dental Cough is of a sonorous hacking character. It 

 arises from sympathetic inflammation of the throat, and is most frequent 

 in third and fourth year, i. e. during the growth of the permanent teeth. 

 It disappears with maturity. 



1070. Dental Fever. 



During the active stage of dentition, some horses suffer from constitu- 

 tional disturbance accompanied by loss of appetite, debility, unthrifti- 

 ness, a tendency to diarrhoea, quickened pulse; but without cough or 

 other symptoms indicating that the fever is due to disease of any internal 

 organs. On examining the mouth, the gums are heightened in colour, 

 swollen and tender, with increase of saliva. Horses from three to four 

 years of age are more subject to this form of dental irritation than those 

 of a more tender age ; and it is perhaps for this reason that horses 

 between two and three years old often stand work better than those 

 between three and four. 



The treatment consists in giving relief to the immediate local cause, 

 and complete rest and suitable diet, till recovery takes place. Surgical 

 aid may be required. 



It will be readily seen from the foregoing enumeration of dental ills, 

 especially affecting the molars, what an important part dentition plays 

 in the physical capacity of the horse during its development, and the 

 great relief which the skilful operator is enabled to afford. It also 

 clearly shows how carefully the molars should be examined for soundness. 



