Lead poisoning. A comprehensive review and report of a case

Lead, a ubiquitous heavy metal which has realized increased use, can cause poisoning by environmental contamination in either its organic or its inorganic form. Lead poisoning can be either acute or chronic, with the latter being the more common. The clinical signs and symptoms of lead poisoning are nonspecific, resulting in a difficult diagnostic problem, especially when it is not industrially related. On occasions, the dentist or oral surgeon may be the first to see an afflicted patient because of oral manifestations.

The effects of local hypothermia on odontogenesis

Cryosurgery, with temperatures ranging from -40 C to -140 C, was performed on 32 developing mandibular third and fourth premolar buds of dogs. Evaluations were made on clinical, radiographic, and histologic bases at prescribed time intervals. There was complete inhibition of odontogenesis in 62.5% of third premolars and 25% of fourth premolars. There was 25% partial inhibition of third premolars and a 56.25% inhibition of fourth premolars. The adjacent developing tooth buds and bone were not affected.

The mechanism of placebo analgesia

The effect of naloxone on dental postoperative pain was studied to examine the hypothesis that endorphins mediate placebo analgesia. All patients had extraction of impacted mandibular third molars with diazepam, N2O, and local block with mepivacaine. 3 h and 4 h after surgery naloxone or a placebo was given under randomised, double-blind conditions. Pain was evaluated on a visual analogue scale. Patients given naloxone reported significantly greater pain than those given placebo. Patients given placebo as their first drug was either placebo responders, whose pain was reduced or unchanged, or nonresponders whose pain increased. Naloxone given as a second drug produced no additional increase in pain levels in nonresponders but did increase pain levels of placebo responders. Nonresponders had a final mean pain rating identical to that of responders who received naloxone as their second drug. Thus the enhancement of reported pain produced by naloxone can be entirely accounted for by its effect on placebo responders. These data are consistent with the hypothesis that endorphin release mediates placebo analgesia for dental postoperative pain.