226 THE WONDERFUL HOUSE THAT JACK HAS 



more rinsing would have made a better job, and very 

 likely have prevented much of the trouble. 



Limewater, milk of magnesia, water in which some 

 bicarbonate has been dissolved, or some specially 

 prepared mouth wash may be profitably used for the 

 last rinsing. All are alkalies and neutralize acid, 

 that is, they make the acid powerless to have any 

 solvent effect upon the teeth. If used just before 

 retiring, they help prevent decay during the night. 

 Where the tooth powder used leaves a slightly alkaline 

 reaction, that of itself will usually be sufficient. Plain 

 precipitate of chalk, being alkaline, fulfills this purpose. 



But even with the best care daily, all decay may not 

 be prevented; and as a diseased tooth may infect 

 those adjoining, much injury may be done. Having 

 one's dentist examine the teeth at least once in six 

 months is an excellent safeguard. Usually a charge 

 is not made if an examination shows no work is neces- 

 sary ; and if cavities are discovered, the more quickly 

 they are filled the better. How foolish some people 

 are to put off visiting the dentist because they dread 

 the possible pain ! If one goes when the cavity is 

 first started, the dentist's work may cause little or no 

 pain. The larger the cavity and the nearer it gets to 

 the hollow part of the tooth, the more painful the 

 filling process may be. 



If a cavity continues uncared for long enough, a 

 peculiar sensation is felt when cold water or food comes 

 in contact with it. When the nerve becomes exposed, 



