The Dental cosmos . The doctor also states that where a tension is brought upon the upperjaw sufficient to cause its contraction, it should also cause some con-traction in the lower jaw. He says, If the buccinator acts as all mus-cles, uniformly throughout its extent of contraction, below its median Fig. 5. Fig. line it is just as efficient in producing a narrow, contracted arch as inits upper portion, and we should expect to find the lower maxilla con-tracted whenever the upper one is, which is contrary to the observation is that instead of contracting the lower jaw the FIRST DIS
The Dental cosmos . The doctor also states that where a tension is brought upon the upperjaw sufficient to cause its contraction, it should also cause some con-traction in the lower jaw. He says, If the buccinator acts as all mus-cles, uniformly throughout its extent of contraction, below its median Fig. 5. Fig. line it is just as efficient in producing a narrow, contracted arch as inits upper portion, and we should expect to find the lower maxilla con-tracted whenever the upper one is, which is contrary to the observation is that instead of contracting the lower jaw the FIRST DISTRICT DENTAL SOCIETY, STATE OE NEW YORK. 205 pressure brought upon the front of the lower jaw flattens it. Insteadof contracting it, just the reverse is found in all cases : the lower jaw isflattened in front and broadened at the sides. As to the orbicularis orispressing upon the incisors : I have here three models of the mouth of aboy who is now ten years old. This case I know from birth. Themodel for Fig. 5 was taken when the child was two years of age. Youwill see there is a nice round arch. The next one (Fig. 6) was taken Fig. 7. Fig. 8.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectdentist, bookyear1890
