MASTICATION.

King Country Chronicle, Volume VII, Issue 583, 9 July 1913, Page 3

MASTICATION.

A previous article' on mastication showed the extreme importance of exercising the jaws by giving babies and young children Borne food needing thorough chewing, instead of limiting them to "pap r " when they have got beyond the stage of other's milk. Thin providing of food which needs work to be done on it is equally important during the second year, and exerts a profounj influence over the "manufacture and Betting" of the permanent teeth if continued until they have all cone through the gums and taken up their life work—to say nothing of the value of proper eating habits as aids to digestion throughout life. To the expectant and nursing mother, thorough mastication is of special significance, and the importance of the whole BUbject CBn scarcely be overestimated. The following extracts from Dr Harry Campbell will help parents to realise the duty they owe to their offspring from first to last in this very practical field of true education :

Maßtication Promotes the Flow of the Saliva and the Insalivation of the Pood. —The more the food is masti cated the more completely it h insalivated. Now, inasmuch as starch is converted by the saliva, first into dextrine and then into maltose, it follows that the whole of the starch of the food ingested may be transformed into maltose within the mouth if only mastication is persisted in long enough; and it is surely better for the individual to manufacture his maltose within the laboratory of his own organism than to have it administered to him in the form of the artificially prepared "malt extract"; yet, strange to say, patients are often allowed these extracts when they are forbidden the starchy foods which they could, by adequate mastication, quite easily convert into maltose for themselves. As a matter of fact, starchy foods, if sufficiently insalivated, are Beldom indigestible. Mastication Increases the Amount of Alpalnie Saliva Passing into the Stomach.—Thus not only prolonging the period of starch digetion in that organ, but influences gastric digestion in other ways; it is probable that a deficiency of alkaline saliva in the stomach is inimical to normal digestion. (Memo by "Hygeia." Mothers should clearly understand that the salivary glands are late in developing, and that therefore starch does not normally form part of the food until the baby is nine months old. After that age riaturo provides for a steadily - increasing flow of saliva. Hence the need for introducing rusks, bread, cereal jellies, etc., to keep pace with the growth of the child's starch-digesting organs.) Mastication promotes the flow of gastric juice, and thus prepares the stomach for the reception of food. This effect is probably produced chiefly through the medium of psychic influence, for the more efficiently mastication is performed the more effectually is the sense of taste excited. Mastication stimulates the heart, and so promotes the circulation. INFLUENCE OF MASTICATION ON THE JAW AND ADJACENT STRUCTURES. Muscles of Mastication. Seeing that all rhythmic muscular constructions stimulate the flow of blood and lymph not only in the contracting muscles themselves, but in the neighbouring parts also, it follows that the exercise of the masticatory muscles, which are far more massive than is generally realised, influences, with their own nutrition, that of the important structures adjacent to them —i.e., the jaw bones, salivary glands, mucous membrane of mouth, soft palate, tonsils, pharynx, and cavities of the nose, etc, ; All these parts are, during mastication, copiously flushed with blood and lymph, their nutrition being correspondingly stimulated, and it is not therefore surprising that in those who from childhood upwards have been accustomed to masticate efficiently they should be well developed the jaws well grown and shapely, the teeth sound and regular, the tongue (for we must not forget that it, too, is a masticatory muscle) and salivary glands large, the nasal and nasopharygenal passages Bpacious, and the mucous membrane of the mouth and adjoining cavities healthy; and that, on the other hand, if those who have never adequately exercised their masticatory muscles these various structures should be correspondingly ill developed and liable to disease. It should be observed that some uf the largest muscles which cause the movements of the lower jaw during mastication, arise from the very region whence adenoids spring. The Jaw Bones.—That the jaws do not attain normal size unless properly exercised is shown by the overcrowded teeth of those brought up on soft foods, even in the absence of that peculiar deformity of the jaws resulting from mouth-breathing, which, as we shall see, is itself the indirect result of inefficient mastication.

The Teeth. —But were there any doubt on these matters, it is only necessary to consider tha teeth themseives to arrive at certainty. Who can contemplate the jaw bones of a six-year-old child, so dissected as to display all the embedded teeth, without being assured of the influence of mastication in promoting their normal development and eruption? Fifty-two teeth meet the view; the entire region from the orbital rims to the inferior border of the mandible is, in fact, a mosaic of them, temporary and permanent, the latter in various phases

of growth, and only by efficient mastication that shall ensure the conditions necessary to it can their adequate development possibly be brought about. It is mastication alone that can stimulate the circulation—in the tooth germs that they may grow, and in the jaw? that, when grown, the teeth shall find room; and mastication, again, is necessary to enable the permanent teeth to take up their normal poaitions, so as to secure a good "bite"—i.e., proper apnosition of the upper and the lower teeth. The pressure of the two rows of tenth against each other makes for a healthy condition alike of the teeth, the sockets containing them, and the surrounding tissues of the gums, inasmuch as it [ stimulates the circulation of tooth pulp, tooth sockets, and adjacent parts. Hence disease uf the teeth and tooth sockets (decay, abscess, etc.) is much more common in the in efficient than in efficient masticatiors. A few words may here be said regarding the influence of mastication in wearing down the teeth. Those who masticate well wear away their teeth considerably. This is due iut so much to the attrition of coarse, hard food against the teeth as to that of the opposing teeth against one another, for it must be rememhered that in normal masticatiun these are not merely pressed vertically one upon another, but also are made to grind against one another by a lateral and sagital movement. If in a person, say, over thirty, we find little cr no wearing down of the teeth, we may be sure that he does not masticate properly; the information which this simple test gives may often cause-us to surprise our patients by passing an accurate opinion on their masticatory habits. I suppose it is because the English people, nurtured principally on soft food, do not wear their teeth down, and still more becauae, not using their teeth properly, these tend to grow out of their ?ocket3, and thus j appear unduly long, that our Continen- j tal neighbours regard us as being j large and long in the tooth, and as | such so frequently represent John Bull | in their cartoons. |