Cavity Blasters

(Sfx: teeth brushing)
     
     SINCE FLUORIDE HAS BEEN ON THE MARKET IN TOOTHPASTES AND MOUTHWASHES
THE WESTERN WORLD HAS SEEN A MARKED DECLINE IN CAVITIES.  THE FLOURIDE
REINFORCES A NATURAL MATERIAL--CALLED HYDROXYAPATITE--IN YOUR TEETH THAT
OTHERWISE CAN QUICKLY SUCCOMB TO THE VARIOUS ACIDS THAT PERVADE YOUR MOTH. 
NEVERTHELESS, SCIENTISTS HAVE BEEN TRYING TO COME UP WITH AN EVEN SURER WAY TO
PROTECT YOUR TEETH AGAINST CAVITIES. SOME HAVE TURNED TO LASERS. 
     PHYSICISTS WOLF SEKA, ALONG WITH JOHN FEATHERSTONE, AT THE UNIVERSITY OF
ROCHESTER, HAS BEEN USING LASER PULSES TO HEAT THE OUTSIDE OF A TOOTH TO A
WHOPPING 1000 DEGREES CENTIGRADE TO SEE IF THAT HELPS PROTECT AGAINST CAVITIES. 
THAT MAY SOUND REALLY HOT, AND SO FAT THEY'VE ONLY TRIED IT ON EXTRACTED
TEETH, BUT SEKA SAYS THAT EVEN IN PERSON IT SHOULDN'T HURT A BIT.

     Seka: "the temperature of 1000 degrees is of course extremely high, but it only extends over an
extremely small region. . .it cannot heat the inside of the tooth by more than a couple of degrees you
would not even feel warming. 

     BUT ON THE OUTSIDE OF THE TOOTH, THAT INTENSE HEAT ADJUSTS THE MAKEUP
OF THE HYDROXYAPATITE MOLECULETO MAKE IT STRONGER.  WHEN LEFT ALONE, THE
MOLECULE COMBINES WITH CARBON ATOMS AND THE COMBINATION ISN'T VERY ACID
RESISTANT.  BUT THE HEAT OF THE LASER BEAM DRIVES AWAY THAT CARBON.

     Seka: "The dental heart tissue actually melts and leaves a more acid resistant hydroxyapatite."

     SEKA AND FEATHERSTONE ARE ONE OF SEVERAL GROUPS OF SCIENTISTS TRYIGN TO
GET THE VERY BEST COMBINATION OF HEAT AND TIMING THAT MAY SOMEDAY BE USED TO
PROTECT YOUR TEETH.  WHILE THE THOGUHT OF LASERS FLASHING AROUDN
ONE'SMOUTH MAY NOT EXCITE THOSE PEOPEL WHO ARE NATURALLY AFRAID OF THE
DENTIST'S OFFICE--IT'S NOT TOO BAD IF YOU CONSIDER THE ALTERNATIVE.

     (SFX: dentist's drill)