Laser helps determine dental health

 A study by Dr. Car­men Gonzales, et al investigated the effect of systemic fluoride intake from birth to 12 weeks on orthodontically induced root resorption and tooth movement in rat mo­lars. Fifty male rats were randomly di­vided into the following 5 groups: a neg­ative control group that re­ceived no so­dium fluoride and had no tooth movement; a positive control group that re­ceived no sodium fluoride but had tooth movement; and 3 experiment­al groups that received 45-ppm sodium fluoride from birth to 2, 4, and 12 weeks, respectively. At week 10, a 50-g nickel-titanium coil spring was ap­plied to the maxillary left first molar for 2 weeks. At week 12, movement of the maxillary first mo­lars was measured in relation to the maxillary second molar on digitized cephalometric radiographs. Mesial and distal roots were examined by using scanning electron and 3-dimensional laser microscopes. The study found that fluoride reduced the depth, volume, and roughness of the resorption craters in the experimental groups. Yet, the area was similar to that in the positive control group. The longer fluoride was administered via drinking water, the smaller the amount of tooth movement ob­served. It concluded that fluoride in drinking water from birth reduced the severity of orthodontically induced root resorption, but the amount of tooth movement was also decreased.