Louis Fiset

Nitrous oxide analgesia in humans: acute and chronic tolerance

&NA; Electrical tooth stimulation was used to investigate whether humans develop tolerance to nitrous oxide (N2O) analgesia within a single administration as well as over repeated administrations. In a double‐blind cross‐over experiment, 77 subjects received a 40‐min administration of 38% N2O at one session and placebo gas at the other. The sessions were separated by 1 week and the order of gas administration was counterbalanced. Acute analgesic tolerance developed for pain threshold but not for detection threshold. There was no evidence of a hyperalgesic rebound effect following cessation of the N2O administration. In a second double‐blind experiment, 64 subjects received both 30‐min of placebo gas and 30‐min of 35% N2O, separated by a 35‐min gas wash‐out period, during each of five sessions. Sensory thresholds were assessed prior to drug or placebo administration (baseline) and between 7–12 and 25–30 min of gas administration. A control group of 16 subjects received only placebo gas at these five sessions. During a sixth session, the experimental procedures were similar to the previous sessions except that the control group received N2O for the first time and the experimental group was sub‐divided to test for conditioned drug effects. For both detection and pain threshold measures, acute tolerance developed during the initial N2O exposure and chronic tolerance developed over repeated administrations. Although chronic tolerance developed, a test for Pavlovian drug conditioning found no evidence of conditioned effects on sensory thresholds. In conclusion, acute and chronic tolerance develop to N2Os analgesic effects in humans.

The anxiolytic effects of intravenous sedation using midazolam alone or in multiple drug techniques

This study examines four drug combinations (midazolam, midazolam-midazolam, fentanyl-midazolam, and fentanyl-midazolam-methohexital) in a placebo-controlled double-blind clinical trial of intravenous sedation. It tests the hypothesis that there is no difference between the anxiolytic effect of the four combinations when compared with a saline placebo. Subjects were 207 mildly anxious young adults having their third molars removed. Cognitive measures of anxiety increased from preoperative levels in the placebo and both midazolam groups (P < .05). The anxiety response remained the same in the fentanyl-midazolam and fentanyl-midazolam-methohexital groups (P > .05). The level of successful anxiolysis ranged from 24% in the placebo group to 74% in the barbiturate group. Using the log likelihood method, comparisons suggest that the drug groups (from midazolam alone to the methohexital combination) have increasingly positive anxiolytic effects even when controlling for the effects of dental fear and intraoperative pain. The fentanyl-midazolam group is 8.1 and the methohexital group is 9.0 times more likely to have had a favorable outcome than the placebo group. Additional analyses of behavioral measures of anxiety yielded parallel results. Global evaluations after surgery were related to the success of anxiolysis for subjects in the active drug conditions (P < .05).

Assessment of a behavioral approach in long-term plaque control using a multiple baseline design: The need for relapse research

Abstract A longitudinal study was undertaken to investigate, in a private practice setting, the effectiveness of a complete behavioral approach to plaque control. Seven middleclass adult patients who would benefit from such a program received comprehensive, personalized behavioral treatment. Control subjects received traditional oral hygiene instruction. At data collection sessions, subjects were given disclosing dyes, and intraoral photographs were taken. Six tooth surfaces appearing in the simplified oral hygiene index were digitized, yielding percent plaque scores. Scores were plotted over time for each subject. Results indicated that for each subject in the experimental condition plaque scores decreased and were maintained at six months, but much of the gains were lost at 12 to 18 months. Subjects in the control group did not show consistent patterns of change.

Dental malpractice experience: a closed claim study.

This study is part of a larger study of closed dental malpractice claims recently funded by the Agency for Health Care Policy and Research, US Public Health Service. This paper focuses on the outcome of malpractice claims against dentists in a major state. Limiting the analysis of dentist closed claims to one state experience allows us to avoid confounding because of differences in legal, market, and sociodemographic characteristics across states and to concentrate

Tort reform and malpractice liability insurance

Legal factors related to the malpractice liability insurance purchased by general dentists in the United States were investigated using a comprehensive multivariate model that assessed the contribution of legal provisions affecting the probability of a malpractice claim, the probability of a payment, and the average size of the payment. General practice dentists in the United States were selected randomly, and 3,048 dentists were studied by mail survey. A number of legal statutes (periodic payment allowed, percentage fault liability informed consent limits, limits on res ipsa loquitor, attorney fee control, some statute of limitations provisions) had the intended effect of reducing the malpractice insurance sought by dentists. Other provisions, such as binding arbitration, may have unintended cost-raising effects. Previous malpractice claims were associated with purchasing greater amounts of insurance. These findings have implications for future changes in the legal system as part of health care reform.

The influence of surgical stress, anxiety and benzodiazepine intravenous sedation on recall of oral surgery

Abstract This study, part of a larger investigation of the efficacy and safety of intravenous sedation in dentistry, reports the prevalance of failure to recall information during third molar impaction surgery and attempts to differentate the effects of stress and benzodiazepines on recall. Both recognition of neutral pictures and the recall of surgical procedures were assessed. Recall failure in the drug groups ranged from zero for recall of stressful procedures, completed before drug titration, to 92 percent of subjects for recognition of the neutral picture presented at 5 minutes after the surgical procedure began. Placebo condition subjects had almost no recall loss. Recall failure was demonstrated to be primarily a function of the volume of midazolam employed. However, operative stress and trait and state anxiety explained some of the findings.

Nonalcohol-based chlorhexidine dental rinse.

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