280 IliK WAVE-FORMED MOUTH. 



Esser saw shear mouth result from the articulation of the jaw being 

 wounded, lateral movement in one direction being shortened, and 

 irregular wear thus induced. 



Prognosis depends on the degree of development, condition of 

 the teeth, and existing complications. The earlier stages escape 

 notice ; it is only when chewing becomes difficult that its presence 

 is suspected. Provided the teeth are still sound and firm, temporary 

 relief may at all events be given ; but where they are loose, or alveolar- 

 periostitis has already set in, the chances of recovery are slight, and 

 in long-standing cases cure is impossible. 



Treatment was formerly confined to removing the sharp edges 

 with the rasp or chisel, and lightening the work of mastication by 

 giving soft food. Even nowadays nothing more can be done if the 

 teeth are loose or shear mouth is moderately developed. But where 

 the patients are young and valuable, and the teeth still firm, relief 

 may be assured, at least for some time, by removing the projections 

 with tooth shears. Moller operated on several cases in this way, 

 and the animals immediately afterwards were able to take their 

 food and masticate quite satisfactorily. If several teeth have to 

 be shortened, the horse must be cast, but the operation is not 

 difficult, and Moller more than once operated on double shear mouth 

 in a quarter to half an hour, and had most excellent results. As 

 to the use of the shears, see section (d) hereafter. 



THE WAVE-FORMED MOUTH. 



The wearing surfaces of the several molars on each side above 

 and below are normally of similar height, and form a plane surface ; 

 but variation of this plane produces the wave-formed mouth. It 

 is generally bilateral, the fourth lower molar being the shortest, the 

 corresponding upper tooth the longest in their particular rows. The 

 molars in front and behind these become respectively longer or 

 shorter. In the lower jaw they are usually too long, in the upper 

 jaw too short. Sometimes the state of things is reversed. 



This form of mouth usually depends on unequal durability of the 

 individual teeth, and sometimes on disease of the alveoli. Slight 

 inequalities cause little discomfort ; but when well developed, and 

 especially if the alveoli are involved, mastication is greatly impaired, 

 and the sharp points and edges wound the opposing soft parts. 

 Certain teeth may be worn down level with the gum, and mastication 

 made exceedingly painful. The disease occurring in early life is 

 especially serious, as it becomes aggravated with age. 



