Dental review; devoted to the advancement of dentistry. . sary to retain the lower jaw5 mm. in a forward pose, when all the muscles are relaxed, variesfrom 30 to 60 grams. This amount, though comparatively small, *Dental Anatomy, Tomes. 0R1GIXAL CGMMUNICA TIOXS. 851 is sufficiently great to render it absolutely impossible for the externalpterygoid to hold the jaw in a fixed forward position. The natural tendency of the muscles is to retain the condylesin their natural position in the glenoid fossae. The incline plane ofthe Kingsley plate, when the jaw is in repose, offers no resistance tothis
Dental review; devoted to the advancement of dentistry. . sary to retain the lower jaw5 mm. in a forward pose, when all the muscles are relaxed, variesfrom 30 to 60 grams. This amount, though comparatively small, *Dental Anatomy, Tomes. 0R1GIXAL CGMMUNICA TIOXS. 851 is sufficiently great to render it absolutely impossible for the externalpterygoid to hold the jaw in a fixed forward position. The natural tendency of the muscles is to retain the condylesin their natural position in the glenoid fossae. The incline plane ofthe Kingsley plate, when the jaw is in repose, offers no resistance tothis natural tendency on the part of the muscles ; and the consequentbackward and forward movement of the condyle from its naturalposition in the fossae to that on the articular eminence where it isforced by the advancement of the jaw, in masticating closure, wouldprevent the production of the physiological changes necessary toestablish a new temporo-maxillary articulation. It is probable thatthe physiological result is a permanent enlargement of the glenoid. Fig. 10. cavity anteriorly and downward. The possibility of bending theneck of the condyle is highly improbable for the following reasons :ist. The constant force is not sufficient. 2d. The period of activity of the masticatory muscles as com-pared with the period of rest is too short. 3d. Observations mentioned above (in reference to the formof the glenoid cavity being dependent upon the occlusion of theteeth) and observations stated later. It was at the termination of two years experimenting withvarious forms of plates, endeavoring to establish a positive temporo-maxillary articulation, that I conceived the idea of a simple method 852 THE DENTAL REVIEW. of jumping the bite, which, while giving the lower jaw the neces-sary freedom to perform every function unconscious of its subjec-tion, prevents the condyles from resuming their former position in
Size: 1741px × 1436px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectdentist, bookyear1901
