DENTISTRY 



1769 



DENTISTRY 



being much practiced in connection with the 

 schools. In some cities dentists are paid from 

 the city funds and are thus enabled to devote 

 a large part of their time to correcting the 

 defects in children's teeth, and to instructing 

 them how to care for their teeth, while in other 

 places examinations only are made, and the 

 parents are, advised to have their children's 

 teeth attended to. The theory that many a 

 case of dullness in school is directly or indi- 

 rectly due to bad teeth was scoffed at but a 

 few years ago, but now it is commonly 

 acknowledged. This is a day of prophylaxis, or 

 preventive treatment. Caries, or decay of the 

 teeth, is caused by a germ or organism that 

 lives and reproduces its kind in the grooves and 

 unclean areas of the teeth. It secretes an 

 acid which dissolves the enamel and enters into 

 the dentine, the soft and porous structure of 

 which the tooth is largely made up. Once it 

 starts, decay progresses rapidly. Clean teeth 

 do not decay. 



Mechanical Dentistry. This includes the 

 branch which deals with making and insert- 

 ing artificial teeth in place of natural teeth 

 that have been extracted. Dental work of this 

 character requires mechanical skill and care- 

 ful observation of any peculiarities of the 

 mouth, in order that the teeth inserted may 

 not be unlike the natural teeth in color, size 

 and shape. Artificial teeth are made of por- 

 celain, and may be affixed to plates of vulcan- 

 ized rubber or to plates of gold or platinum 

 made to fit the gums. Teeth that have been 

 badly broken by decay may be covered with 

 gold and thus restored to usefulness. The 

 practice of crowning teeth with gold is de- 

 creasing. A comparatively-recent process, 

 showing a marked advance over older methods 

 of inserting artificial teeth, is known as bridge 

 work. The teeth are fixed by bands, springs 

 or crowns to the natural teeth in the mouth, 

 and last much longer than teeth inserted by 

 any other method. 



Painless Dentistry. This phrase once car- 

 ried little consolation to a patient with aching, 

 sensitive teeth, and was a favorite topic of 

 humorous paragraphers. They intimated that 

 it was painless to the dentist only, which was 

 quite the truth. To-day, however, the dental 

 profession, down to its most inconspicuous 

 members, may actually practice almost pain- 

 less dentistry. 



An ingenious device contains nitrous oxide 

 and oxygen in separate compartments, but 

 when administered to the patient the two gases 



may be mixed in any proportion. When opera- 

 tive work is done on teeth more oxygen than 

 nitrous oxide is inhaled; the result is absolute 

 absence of pain, but all other senses than feel- 

 . ing are retained; in case of extraction of teeth 

 less oxygen and an added quantity of other 

 gas renders the patient unconscious, with sub- 

 sequent recollection of only a delightful dream. 

 No ill effects follow its administration; indeed, 

 the presence of oxygen, a stimulating agency, 

 assures the safety of the patient. Dentists are 

 adopting this device rapidly and the dental 

 chair is losing much of its old-time terror. 



Another advance was recently made in the 

 introduction into dental practice of what is 

 known as conductive anesthesia, or nerve- 

 blocking. This consists in injecting an anes- 

 thetic into a nerve controlling the affected tis- 

 sues, as a result of which the patient ceases 

 to have any sensation whatever in those par- 

 ticular tissues. The effect of the nerve-block- 

 ing sometimes lasts two hours, and the method 

 has been found especially valuable in cases 

 where the operation is delicate and tedious, as 

 the extraction of an impacted wisdom tooth. 

 It is also a welcome boon to patients who are 

 high-strung. 



Antiquity of Dentistry. It has often been 

 stated that in the days of ancient Egypt it 

 was customary to fill cavities in teeth with 

 gold.. Gold has been found in the teeth of 

 mummies, according to some writers. That 

 fact has never been fully established, but that 

 dentistry was practiced in the days of the 

 Pharaohs is undoubted. Many centuries before 

 the Christian Era, gold crowns were worn, 

 bridge work was not unknown, and single arti- 

 ficial teeth were inserted in the place of those 

 newly extracted. Knowledge of the art, how- 

 ever, was lost, and its revival is a matter of 

 modern history. 



Dental Schools. For the purpose of giving 

 instruction in dental surgery and mechanical 

 dentistry, schools have been established in many 

 large cities of the world. The first of these 

 schools in America was founded in Baltimore 

 in 1839. A few years later the Ohio College 

 of Dental Surgery was established. Nearly all 

 universities in the United States and Canada 

 now have dental schools and confer degrees 

 on graduated students. The course of study 

 usually embraces four years, during part of 

 which practical experience is gained. A high 

 school course is necessary before admission 

 to any dental school can be obtained. See 

 TEETH. WJ-.L. 



