10 METHOD OF TAKING IMPRESSIONS 



cient to secure a perfect impression of every 

 part. 



As the whole affair scarcely exceeds a quarter 

 of an inch in thickness, it is easily removed from 

 the smallest mouth. 



The cases next in difficulty to those I have just 

 referred to are those of the lower jaw, where one 

 or two of the molar teeth are absent on both 

 sides, together with two or three of the front 

 teeth, allowing the wisdom teeth to incline for- 

 wards and inwards, and the other teeth that 

 remain to fall towards each other ; the difficulty 

 in such case is often considerably increased by 

 the superior molar teeth, by having become elon- 

 gated by the loss of their antagonists of the lower 

 jaw, and so preventing the impression being lifted 

 up sufficiently to clear the lower teeth. In such 

 cases, the advantage to be derived from fitting a 

 plate to the mouth in the way I have just de- 

 scribed, and substituting a thin sheet of gutta- 

 percha for wax, is sufficient to compensate fully 

 for the extra trouble it involves. Indeed, I am 

 doubtful whether it is extra trouble, whether the 

 greater accuracy thus obtained does not more 

 than compensate for the first trouble in the fewer 

 visits paid by the patient for alterations. 



The difficulty of obtaining satisfactory impres- 

 sions of such cases has been felt by every one, 

 and has given rise to the employment of various 

 substitutes for wax, which, however, upon being 



