Clinical evaluation of ferric oxalate in relieving dentine hypersensitivity.

Previous in vitro permeability and scanning electron microscopic (SEM) studies have demonstrated the effectiveness of the oxalate ion in dentine permeability reduction and effective tubule occlusion. The aim of this randomized double-blind, split mouth 4-week clinical study, therefore was to determine whether a 1-min application of ferric oxalate (Sensodyne Sealant) on exposed root dentine was effective in reducing dentine hypersensitivity (DH). Thirteen subjects [8F:5M, mean age 46.2 (s.d. 4.15) years] completed the study. The subjective response was evaluated by tactile, thermal and evaporative methods of assessment. Data were collected at baseline and post-application at +5 min and 4 weeks. Analysis was based on paired t-test (P=0.05) and Wilcoxon-Mann-Whitney tests. No statistically significant differences were noted between ferric oxalate and placebo preparations at +5 min and 4 weeks for any of the test stimuli. There was, however, a clear trend towards immediate reduction (+5 min) in DH reverting back to baseline values at 4 weeks with the exception of the Biomat Thermal Probe mean values, which maintained the reductions in DH compared with placebo. The results of the present study demonstrated that a 1-min application of ferric oxalate is both rapid and effective in reducing DH although its long-term effectiveness still needs to be determined.

Clinical evaluation of a potassium nitrate dentifrice for the treatment of dentinal hypersensitivity.

The effectiveness of a 5% potassium nitrate dentifrice as a daily home treatment for dentinal hypersensitivity was evaluated in a double-blind study in 36 Japanese subjects who complained of cold and/or tactile hypersensitivity. The subjects were divided into 2 groups, with 18 being given a 5% potassium nitrate dentifrice (treated group) and the other 18 a vehicle paste (control group). Both groups were instructed to brush their teeth 2 x a day. The hypersensitivity levels of the affected teeth were assessed by 2 stimuli, one tactile and the other cold air, and by the perception of pain. The results of all 3 assessment methods indicated that the potassium nitrate dentifrice significantly decreased the level of hypersensitivity at weeks 4, 8, and 12. In the treated group, a rapid decrease of positive scores for both the cold air stimulus and the subjective symptoms appeared from week 2. Although a significant decrease of the assessment score was also observed in the control group, the reduction rate of the score was much greater in the treated group by all 3 assessment methods at weeks 4, 8, and 12. Complete relief of subjective symptoms throughout the 12 weeks' examination was noted in 67% of the subjects in the treated group, but in only 6% in the control group. These results suggest the usefulness of a 5% potassium nitrate dentifrice in Japanese patients with dentinal hypersensitivity.

Improved diagnostics: clinical evaluation of a color-coded, polymeric periodontal probe.

The objective of this study was to compare the accuracy, reproducibility and patient comfort of a newly designed, color-coded, polymeric periodontal probe to a traditional, color-coded metal probe. Twenty-four adult subjects with varying degrees of periodontal disease (from slight to severe) reported for two visits, one week apart. A randomization schedule for probe use was adopted over the two visits so that the gingival crevices in two quadrants were probed with the same probe (metal or polymeric) providing reproducibility information for each probe, while the other two quadrants were probed first with one probe then the other for comparison data yielding information on accuracy. A bleeding index was obtained using the same schedule. Clinical scoring was performed by the same examiner. After probing each quadrant, subjects rated discomfort using a visual analog scale (VAS). Results showed no significant difference in depth readings greater than 2 mm between the polymeric and metal probes (3.41 +/- 0.37 mm vs. 3.38 +/- 0.32 mm, p = 0.55). Significantly less discomfort (assessed by VAS) was recorded by patients after polymeric probe use (3.70 +/- 2.40 cm vs. 4.44 +/- 2.49 cm, p = 0.015). The bleeding index indicated significantly less bleeding with the polymeric probe (0.80 +/- 0.56 vs. 1.24 +/- 0.65, p = 0.0001). Both the polymeric and metal probes were found to produce highly reproducible results in all measures across visits.

Comparison of nonsteroidal anti-inflammatory drugs, ibuprofen and flurbiprofen, with methylprednisolone and placebo for acute pain, swelling, and trismus.

Pain, swelling, loss of function, and hyperthermia are acute postoperative sequelae of inflammation due to tissue injury during surgical procedures. Pharmacologic strategies for minimizing the clinical manifestations of surgical trauma are often directed toward blocking the formation or inhibiting the effects of the biochemical mediators of acute inflammation. This study compared two nonsteroidal anti-inflammatory drugs (NSAIDs), flurbiprofen and ibuprofen, with a prototype glucocorticoid, methylprednisolone, in two replicate placebo-controlled studies for suppression of inflammation due to the surgical removal of impacted third molars. The results indicate that NSAIDs produce greater initial analgesia than do steroids, whereas steroids result in greater suppression of swelling and less loss of function. Examination of the pooled data from the two studies indicates that NSAID pretreatment results in a modest suppression of swelling in comparison with placebo. These data suggest that the acute analgesic effects of NSAIDs in the oral surgery model are due to suppression of a nociceptive process, presumably prostaglandin formation, rather than a generalized anti-inflammatory effect.

Designing hypersensitivity clinical studies.

A dentinal hypersensitivity study is really a clinical pain study. The fundamental difficulties in reproducibly and reliably measuring pain impact heavily on the study. Other critical issues include investigator and subject selection, study design, randomization strategy, study duration, sample size, and statistical analysis. This article discusses principles involved in establishing the efficacy of a desensitizing agent.

Epinephrine suppresses stress-induced increases in plasma immunoreactive beta-endorphin in humans.

The present study evaluated the hypothesis that increased plasma levels of epinephrine (EPI) stimulate immunoreactive beta-endorphin (i beta END) secretion in humans experiencing a mild stress. The stressor consisted of intraoral injections of a local anesthetic solution (with or without EPI) just before the surgical extraction of impacted third molars in 26 awake unsedated patients. The EPI group experienced a 30-fold increase in plasma EPI levels by 2 min after injection; these concentrations were physiologically active, as evidenced by increased pulse rate and systolic blood pressure. However, compared to a no EPI control group the EPI group had a significantly reduced i beta END response to the stressor, as evaluated by comparison of plasma levels at individual time points, maximal increases in plasma i beta END levels, and areas under the time-response curve. Whereas there was no association between plasma levels of EPI and i beta END in the EPI group (r = 0.119; P = NS), EPI and i beta END levels were strongly related in the no EPI group (r = 0.82; P less than 0.001). These results do not support the hypothesis of a stimulatory effect for EPI on i beta END release and, instead, suggest that an inhibitory relationship may exist in humans experiencing stress. The association between EPI and i beta END responses observed in the control group during this form of stress appears to be due to activation of a common central neural element.

Bradykinin is increased during acute and chronic inflammation: therapeutic implications.

Bradykinin is a potent pain-producing substance, yet little is known about its role in inflammation. The present study measured circulating levels of immunoreactive bradykinin in a clinical model of acute inflammation (oral surgery) and chronic inflammation (rheumatoid arthritis) and in the rat carrageenan model of inflammation. The effects of a kallikrein inhibitor (soybean trypsin inhibitor) on blocking bradykinin synthesis in vitro and its analgesic actions in the rat model were also evaluated. Levels of immunoreactive bradykinin increased threefold to fourfold during oral surgery. Levels were twofold to threefold greater in patients with rheumatoid arthritis compared with control subjects. Levels of immunoreactive bradykinin increased twofold in rats during carrageenan inflammation. Soybean trypsin inhibitor blocked synthesis of bradykinin in vitro and possessed analgesic activity in rats. The results indicate that the bradykinin system is activated during inflammation. Kallikrein inhibitors may represent a new class of analgesic/antiinflammatory drugs.

Pharmacologic rationale for the treatment of acute pain.

This article reviews peripheral mechanisms involved in the production of dentinal pain and acute inflammatory pain. The endogenous analgesic system, located in the central nervous system, is also reviewed. The pharmacology of peripheral analgesics (such as aspirin-like drugs), local anesthetics and central analgesics (such as opiates) are discussed. Based on this information, a rational therapeutic strategy, directed toward minimizing the perception of pain and the experience of side effects, is presented.

Plasma epinephrine levels and cardiovascular response to high administered doses of epinephrine contained in local anesthesia.

The effects of administering an epinephrine-containing local anesthetic on plasma catecholamine levels and cardiovascular parameters were evaluated. Significant elevations were observed following administration of 8 dental cartridges of 2% lidocaine with epinephrine 1:100,000 (144 µg) throughout the 20 minute observation period, while minimal changes were observed in the patients who received 6 cartridges of 3% mepivicaine. One minute after injection, the mean plasma epinephrine level in the group receiving epinephrine was 27.5 times higher than baseline. Concurrent elevations in systolic pressure (15%), heart rate (33%), and the rate-pressure product (52%) were also observed. These results indicate that significant amounts of epinephrine can be systemically absorbed following intraoral injection and the absorbed epinephrine can alter the cardiovascular status of the patient.