64c Canadian Arctic Expedition, 1913-18 



Coincident with this extreme wear of the teeth the dental pulps have taken 

 on their original function with conspicuous success. Sufficient new dentine 

 of fine quality has been formed to obliterate the pulp chambers and in some 

 cases even the root canals of the teeth. This new growth of tissue is found in 

 every case where access to the pulp chambers has been threatened. There has 

 therefore been no destruction of the pulps through infection and consequently 

 alveolar abscesses are apparently unknown. Perhaps this is just as good a 

 place as any to mention the fact that in all the teeth examined there is not 

 the slightest trace of caries. Salivary calculus too, even in the oldest skulls, 

 with one exception which will be referred to later, is entirely absent, as is also 

 any trace of pyorrhoea, or resorption of the alveolar margins. These latter, 

 however are thicker than those of civilized races and the blood supply is abundant. 

 An edge to edge occlusion has a further result which is conspicuous in a very 

 large percentage of the skulls examined. This is the shallow broad glenoid 

 fossa and the flattened eminentia articulatis which are typical of the Eskimo 

 race. A reference to the plate will show how pronounced these characteristics 

 are. It has been shown by eminent dental authorities^) that the movements 

 of the mandible during mastication are governed by the guiding action of the 

 canine teeth and the inclined planes on the cusps of the premolars and molars. 

 The varied actions of the condyles are the result of these movements and not 

 their cause. As a corollary to this it may be said that the depth, form and 

 extent of the glenoid fossa will vary according to the antero-posterior curvature 

 of the occlusal plane and the extent of overbite exhibited by the anterior teeth 

 with consequent restriction or non-restriction of movement as the case may 

 be. In connection with this important point it might be well to point out that 

 the anatomy text-books are undoubtedly wrong when they state that the 

 mandible is a lever of the third class.('). 



By reference to tables I and II, it will be seen that the average measure- 

 ments of the Eskimo teeth tend to be greater than those of the more civiUzed 

 races. This is particularly true in the molar series which, unlike the civilized 

 dentition, tends to revert to the generalized mammalian type where the molars 

 increase in size in the antero-posterior direction. The teeth as a whole are more 

 symmetrical and stick closer to the ideal typal forms than do those of the white 

 races. There is in these jaws no sign of extremes in root development; nor, with 

 the exception of the third molar, where variation is" world wide, is there any 

 indication of the fusion of molar roots spoken of by Wingate Todd(^) as common 

 in the Eskimo. Prominence of the lingual molar roots, spoken of by Knowles(^) 

 is nowhere greater than might be expected. In my opinion in individual Eskimo 

 teeth there is far less variation from the mean than in any of the civiUzed races, 

 and in this race we have the finest typal forms of teeth and the best dentitions 

 in the world. Owing to their food habits ('■') I am strongly inclined to 

 think that during the lapse of time not only the jaws but the teeth have been 

 growing progressively larger. 



One or two other facts are worthy of notice. An examination of the max- 

 illary sinuses shows that in no case is there a projection of the roots of the molars 

 or premolars into them. It was further noted that these sinuses are extremely 

 large, with walls so thin as to be translucent. Apart from their function as 

 resonating chambers, with the ample blood supply and fatty tissue of the cheeks 

 covering them, it occurred to me that they might act as reservoirs for warm 

 air which would aid materially the mucous membranes of the nose in the process 

 of respiration when temperatures are low. 



In the mandibles of adult individuals a pronounced reinforcement of the 

 alveolar process on the lingual sides of the, premolar teeth which gradually 

 vanishes as the molar series is reached is to be noted. This extraordinary growth 

 of bone tissue (in specimen F. 31 it attains a thickness of 11 mm. below the 2nd 

 premolar), is pecuUar to the Eskimo. Hrdlicka states that— "it is undoubtedly 



