Effect of quarterly treatments with a chlorhexidine and a fluoride varnish on approximal caries in caries-susceptible teenagers: a 3-year clinical study.

The aim of this study was to compare the effect of two different dental varnishes on approximal caries incidence in teenagers with proven caries susceptibility during a 3-year period. Two hundred 13- to 14-year-old subjects exhibiting at least two approximal enamel caries lesions were selected to take part in the study. One hundred and eighty subjects participated after informed consent and were randomly assigned to two equally sized groups. One group was treated with a fluoride varnish (FV, Fluor Protector) containing 0.1% F every 3rd month and the participants of the other group were treated in the same mode with a chlorhexidine varnish (CV, Cervitec((R))) containing 1% chlorhexidine and 1% thymol. In total, each subject was treated 12 times during the experimental period. Approximal caries including enamel lesions (DMFS(appr)) were recorded from four bitewing radiographs exposed at the start and end of the study. The mean (+/-SD) caries prevalence at baseline was 2.2+/-3.4 in the FV group and 2.5+/-4.0 in the CV group. After 3 years, the average approximal caries incidence was 2.7+/-3.1 and 3.1+/-3.5 in the FV and CV groups, respectively. The differences at baseline and after 3 years were not statistically significant. In conclusion, treatments every 3rd month with either a fluoride- or a chlorhexidine/thymol-containing varnish showed a promising effect with low approximal caries incidence and progression in teenagers with proven caries susceptibility.

Evaluation of the use of the argon laser in repairing rat and primate nerves.

The argon laser coagulates blood selectively, making it an adherent material. Argon laser energy is almost completely absorbed by red blood cells and does not seem to affect white nerve tissue. To demonstrate the technical feasibility of laser repair for severed nerves, we cut the sciatic nerves of rats and the median nerves of nonhuman primates and then repaired them by use of an argon laser beam delivered through a 400 microns optical fiber and handpiece that was developed in our laboratory. Autogenous blood was spread around the group of fascicles at the repair site and was then coagulated with the laser to form a minitubule around each fascicle group. Transmission and scanning electron microscopy showed that the repairs appeared technically superior to control sutured nerves and that the laser apparently had no untoward effects on either the repair site or on the control nerve. The minitubules seemed to channel the axon sprouts into the distal tubules extremely well and to prevent ingrowth of scar tissue at the juncture site.