Preoperative nonsteroidal anti-inflammatory medication for the prevention of postoperative dental pain

It is predictable for patients to experience postoperative pain and inflammation. Until recently, therapeutic strategies for the management of these sequelae have been symptomatic rather than preventive. This article reviews prophylactic use of nonsteroidal anti-inflammatory medication for preventing postoperative discomfort, and includes recommendations on patient selection and medication regiment.     

A controlled study of the association of various dental anomalies with hypodontia of permanent teeth

Although hypodontia, or oligodontia, is one of the most common human dental anomalies observed, there have been few studies on the association of other anomalies occurring with it. The present investigation of 1032 patient records found that 65.7% of patients with hypodontia showed ankylosis of primary molars compared to only 1.5% of control children (P less than 0.001). In addition, taurodontism of the mandibular first permanent molar was observed in 34.3% of hypodontia cases compared to 7.1% in the controls (P less than 0.001). Other dental anomalies significantly associated with hypodontia include enamel hypoplasia (11.9%, P less than 0.01) and conical incisors (8.9%, P less than 0.01). In contrast, there were significantly more impacted teeth in control children compared to the hypodontia group. The results indicate that for patients with missing permanent teeth, clinicians should be alert to the possibility of these associated anomalies and their accompanying clinical implications.     

Surface electromyography, force and single motor-unit data for inhibitory reflex responses in human masseter at two levels of excitatory drive

The inhibitory reflex response evoked by mildly noxious lip stimulation was tested in up to 100 trials at two different levels of pre-stimulus excitation. To regulate that excitation, the subject voluntarily controlled the firing rate of one motor neurone at 10 Hz, and then at 15 Hz while the reflex was tested. When the frequency of the motor-unit action potential (MUAP) in the controlled unit increased or decreased, the frequency of other active units' MUAPs also changed in parallel: that is, the frequency of one MUAP was an index of whole muscle excitation. The inhibitory response in the surface electromyogram (EMG) was quantitated by rectifying and averaging the signal, and by measuring its depth and area. The best correlation between the responses evoked in single units and the response in the whole muscle EMG at the two levels of excitation was obtained when the area of inhibition in the surface record was normalized to the pre-stimulus EMG level. The inhibitory response to lip stimulation in the masseter EMG decreased when the level of pre-stimulus excitation in the muscle was increased. This was confirmed using the reflex response in the averaged force data. The findings suggest that controlling one motor unit's firing rate is a useful method for controlling the whole-muscle excitation in quantitative reflex studies.     

Antimicrobial action of natural substances on oral bacteria

The antimicrobial action of natural substances was investigated in vitro against oral bacteria including Streptococcus sp., Actinomyces sp., Actinobacillus sp., Bacteroides sp., Capnocytophaga sp., Eikenella sp., Fusobacterium sp. and Propionibacterium sp. Among the natural substances tested, hinokitiol was the most inhibitory to oral bacteria. Cinnamon bark oil, papua-mace extracts, and clove bud oil in spice extracts were also inhibitory against many oral bacteria. Egg white lysozyme exhibited antimicrobial action against the periodontitis associated bacteria.     

Nicotine effects on PGE2 and IL-1β release by LPS-treated human monocytes

Cigarette smoking is a major risk factor in the development and further progression of periodontitis. However, little is known regarding the pathogenesis of smoking-related periodontal diseases. The purpose of this study was to examine the effects of nicotine, alone and in combination with lipopolysaccharide (LPS), on monocyte secretion of bone-resorbing factors, PGE₂ and IL-1β. Peripheral blood monocytes (PBM) were isolated by counterflow centrifugal elutriation from 15 healthy, non-smoking donors. PBM were incubated for 24 h in RPMI 1640 containing nicotine (0, 50 μg/ml, I μg/ml, 10 μg/ml and 100 μg/ml) with or without 10 μg/ml Porphyromonas gingivalis LPS or Escherichia coli LPS. Culture supernatants were assayed for PGE₂ and IL-1β by ELISA. None of the nicotine preparations resulted in significant PBM secretion of PGE₂ and IL-1β above that of unstimulated cultures. However, PGE₂ release was potentiated 1.7-fold by the combination of P. gingivalis LPS and 10 μg/ml nicotine relative to P. gingivalis LPS alone (p<0.05, one-way ANOVA). Prostaglandin E₃ release also was potentiated 3.5-fold by P. gingivalis LPS and 100 μg/ml nicotine relative to P. gingivalis LPS alone (p<0.00001, one-way ANOVA) and 3.1-fold by E. coli LPS and 100 μg/ml nicotine relative to E. coli LPS alone (p<0.00001, I. one-way ANOVA). IL-1β secretion was lower for either LPS plus 100 μg/ml nicotine relative to LPS alone, although not significantly. These data demonstrate upregulation of LPS-mediated monocyte secretion of PGE₂ by nicotine and suggest a potential role for nicotine in periodontal disease pathogenesis.     

Keratin proteins in human oral mucosa

We have examined the keratin proteins in normal human oral mucosa from 6 different regions including hard palate, buccal mucosa, tongue, gingiva and floor of the mouth. Urea-dithiothreitol extracts of EDTA separated epithelia were analysed by SDS-PAGE and immunoblotting. Eight samples from each region were investigated and showed very little individual variation in the keratin profile on Coomasie Blue-stained gels. The keratinizing hard palate and gingiva expressed identical patterns and resembled the pattern of epidermis from the flank region. The normally non-keratinizing buccal mucosa and the mucosa of the floor of the mouth expressed polypeptides distinctly different from those of the keratinizing epithelia and lacked the high molecular weight keratins. The dorsal surface of the tongue and the commissure region showed a pattern intermediate between keratinizing and non-keratinizing epithelia. The greater sensitivity of the immunoblotting technique revealed that the non-keratinizing epithelia synthesized one of the high molecular polypeptides and that the tongue produced all the bands found in keratinizing epithelia, but in very small quantities. There are, thus, distinct differences in the keratin expression of oral epithelia which are related to the pattern of keratinization assessed histologically.