The radiological prediction of inferior alveolar nerve injury during third molar surgery

The surgical removal of an impacted mandibular third molar may result in damage to the inferior alveolar nerve and may cause disabling anaesthesia of the lip; anaesthesia of the lower gingivae and anterior teeth may also result. Assessing the likelihood of injury depends to a great extent on preoperative radiographic examination. Seven radiological diagnostic signs have been mentioned in the literature; the reliability of these signs as predictors of likely nerve injury have been evaluated through retrospective and prospective surveys. Three signs were found to be significantly related to nerve injury and a further two were probably important clinically.     

Serum antibody response to antigens of oral gram-negative bacteria by cats with plasma cell gingivitis-pharyngitis

The etiology of a form of periodontal disease in domestic cats known as plasma cell gingivitis-pharyngitis is not understood. Actinobacillus actinomycetemcomitans and Bacteroides species have been strongly implicated as the cause of periodontitis in humans and other mammalian species, and most affected patients manifest serum antibodies reactive with the infecting bacteria. We and others have isolated Bacteroides species from the oral flora of cats. Using enzyme-linked immunosorbent assay (ELISA) and immunoblot procedures, we measured serum antibodies in affected and control cats reactive with human isolates of A. actinomycetemcomitans, B. gingivalis, and B. intermedius, and purified lipopolysaccharide (LPS) from these and other species, and Bacteroides of cat origin. Affected cats had serum antibody titers reactive with these Gram-negative anaerobic bacteria that were significantly elevated relative to those of normal control cats. The quantitatively major antigens recognized by cat serum antibodies are proteins; this contrasts sharply with serum antibodies from humans with juvenile periodontitis, where LPS is the quantitatively major antigen fraction. Our data support the idea that plasma cell gingivitis-pharyngitis in cats may have a bacterial etiology, and that Gram-negative anaerobes similar to those that cause periodontitis in humans and other mammals may be involved.     

Effect of an acute maternal fluoride dose on fetal plasma fluoride levels and enamel fluoride uptake in guinea pigs

We conducted this study to measure maternal plasma, fetal plasma, and fetal enamel fluoride concentrations for four hours following an oral F dose to near-term pregnant guinea pigs. We placed female guinea pigs on de-ionized (Group I) or 3-ppm-F (Group II) drinking water prior to breeding and during gestation. On the 57th day of gestation, we administered a maternal dose of NaF solution (0.6 mg F/kg) by stomach tube. We collected samples of maternal plasma, fetal plasma, and fetal enamel at baseline, at 15 and 30 min, and at one, two, and four h after administration of the dose. We assayed samples for F using a modification of the micro-diffusion and ion-specific electrode method. Group I mean baseline F values were: maternal plasma, 0.016; fetal plasma, 0.002; and fetal enamel, 7.0 ppm. Group II mean values were: 0.055, 0.004, and 19.0 ppm. After the maternal fluoride dose, the mean maternal plasma [F] rose sharply for 30 to 60 min and declined to about 50% of peak values by four h. Fetal plasma [F] changed less in absolute values, but similarly to maternal changes relative to baseline. Fetal enamel mean [F] rose more in Group II than in Group I. Baseline F status had an important effect on F uptake in fetal enamel following an acute maternal fluoride dose.     

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.     

Association of specific bacteria with some endodontic signs and symptoms

Although a wide range of bacterial species has been isolated from infected dental root canals it remains necessary to determine whether any particular group of such bacteria is associated with specific endodontic symptoms and clinical signs. In this study 30 root canals were examined microbiologically; of these, 14 were associated with pain, 20 with tenderness to percussion, 23 presented with wet root canals, seven with swelling, five with purulent exudate and four with a sinus. Clinical and microbiological correlation was observed particularly with regard to pain where anaerobes were isolated from 93% of painful canals and only from 53% of painfree canals. The former yielded means of 2.5 anaerobic species and 1.6 facultative species per canal, compared with 1.5 and 2.4 in painfree canals. Prevotella spp. were isolated from 64.2% of painful canals and 12.5% of painless canals (P<0.01) similarly, peptostreptococci were isolated from 71.4% of painful and 31.3% of painless canals (P<0.05). It was concluded that a significant association exists between pain and the presence of Prevotella and Peptostreptococcus spp. in dental root canals.     

Kieferorthopädische Behandlung erwachsener Patienten-Beraten und Überwachen

Zusammenfassung Die Beratung und Betreuung von erwachsenen Patienten sollte dem Prinzip der partnerschaftlichen Kommunikation und Interaktion folgen und den Erwachsenen in den Stand setzen, eigenständig in Kenntnis der Vorteile und Nachteile einer kieferorthopädischen Behandlung zu entscheiden und einsichtig am Prozedere der Behandlung nach Maßgabe der vom Patienten zu erbringenden Leistungen zu partizipieren.

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Summary Advising and taking care of adult patients should be a principle of partnership communication. The adult must be informed as to the nature of the orthodontic treatment planned, the advantages and disadvantages. Thereby the patient is in a position to make a decision and is aware of the degree of participation needed to ensure a successful outcome of treatment.

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Résumé Lors de la consultation et du traitement de patients adultes, il est nécessaire qu'il s'établisse un contact et un engagement réciproques. Ceci permettrait aux patients de se décider en toute indépendance, en connaissant les avantages et désavantages d'un traitement orthodontique et en prenant une part active au traitement.

     

Effect of autonomic nerve stimulation on bleb formation in striated duct cells of the rat submandibular gland

Several previous investigations have shown that blebs form on the apical surface of the striated duct cells of the rat submandibular gland on feeding after starvation. In the present report the influence of autonomic nerve stimulation on bleb formation was studied by electron microscopy. Both parasympathetic and sympathetic stimulation were performed, using electric nerve stimulation. In addition, sympathetic nerve stimulation in combination with alpha- or beta-adrenergic blockers was used. Massive bleb formation took place in response to sympathetic nerve stimulation. This response was almost completely abolished by the administration of alpha- but not by beta-adrenergic blocker. Bleb formation was not seen after parasympathetic nerve stimulation.     

A clinical comparison of three anterior restorative resins at 3 years

An in vivo comparison was made of three different types of restorative resins: a conventional composite resin, a chemically cured microfilled resin, and a small-particle, glass-filled, visible light-cured composite resin. Twenty-eight sets of three restorations were placed 20 patients and examined using the Ryge rating system. All resins performed well and were not significantly different from one another at 1 year. After 3 years, all materials were considered satisfactory, but the conventional composite resins had significantly more surface roughness than did the other resins. Each of the resin materials also declined in color match after 3 years.     

Bacteriological studies on endodontic paper points

Four brands of endodontic paper points were subjected to tests for sterility, antibacterial activity, and suitability as vehicles for bacteriological sampling procedures. No brand showed growth in the sterility assay. One brand showed weak but reproducible antibacterial activity. Recovery of viable bacteria after absorption into the points varied and appeared to depend both on the brand of point and on the bacterial strain used. One brand appeared ineffectual for clinical bacteriological sampling procedures.     

Colonization of the human oral cavity by a strain of Streptococcus mutans

Streptococcus mutans strain JH1001 produces a bacteriocin that can kill virtually all other strains of this micro-organism. The ability of JH1001 to colonize the human oral cavity was tested in a study involving five subjects and three different infection regimens, all of which involved multiple exposures to large numbers of organisms. Two and one-half years after infection, JH1001 was found to have persistently colonized three of the subjects. The indigenous S. mutans in one subject were reduced below the level of detection. Levels of (total) S. mutans and S. sanguis were not affected in persistently colonized subjects. Mutants of indigenous S. mutans resistant to the bacteriocin were not observed. The results indicate the importance of host variability and infection regimen for superinfection by this strain of S. mutans. The efficient replacement of indigenous S. mutans by JH1001 in one subject lends support to the eventual application of replacement therapy to the prevention of dental caries.