Dental caries and microbial acid production in twins

OBJECTIVE: To determine the relative contribution of genetic and environmental stimuli on dental caries traits and microbial acid production in a twin model. METHODS: Dental caries examinations and microbial acid production assays were performed on 388 pairs of twins 1.5-8 years old from the city of Montes Claros, Brazil. Genotyping 8 polymorphic DNA markers determined zygosity. Caries exams followed NIDCR criteria modified to distinguish white spot lesions from cavitated lesions. Surface-based caries prevalence rates (SBCPR) were computed and lesion severity was determined by a weighted index (LSI). Biofilm samples were collected from the tongue using a lactic acid indicator swab. Assay scores were categorized based on acid formation as 1 = low, 2 = medium, and 3 = high. Heritability analyses were performed using the SOLAR software package. RESULTS: Heritability estimates for SBCPRs, LSI and for microbial acid production were H = 76.3 (p < 0.001), H = 70.6 (p < 0.001), H = 16.2 (p = 0.0078), respectively. Treating microbial acid production as a covariate in the SBCPR and LSI models did not significantly alter the heritability estimates, i.e. H = 76.5 (p < 0.001) and H = 70.8 (p < 0.001), respectively. CONCLUSIONS: These results suggest that variation in dental caries surface traits has a significant genetic contribution and that microbial acid production is modulated by the environment.     

Haemostatic management of intraoral bleeding in patients with von Willebrand disease

OBJECTIVES: To develop plans for the haemostatic management of intraoral bleeding in patients with von Willebrand disease (VWD). SUBJECTS AND METHODS: Thirty-seven episodes of haemostatic management of intraoral bleeding in 19 VWD patients were analysed retrospectively based on the medical records. RESULTS AND CONCLUSIONS: When performing tooth extractions in patients with type 1 or 2A VWD [responsive to 1-deamino-8-D-arginine-vasopressin (DDAVP)], 0.35-0.4 microg kg(-1) of DDAVP should be administered intravenously at three times. In patients with type 2A VWD (unresponsive to DDAVP) or patients with type 2B or 2N VWD, 50-90 U [as ristocetin cofactor (VWF:RCof)] kg(-1) of a factor VIII concentrate containing von Willebrand factor (FVIII/VWF concentrate) should be administered twice in routine extractions, and four to six times in surgical extractions. Gingival bleeding related to primary teeth can be mostly managed by pressure haemostasis alone. However, when treating gingival bleeding caused by marginal periodontitis, it is often necessary to administer 0.4 microg kg(-1) of DDAVP or 40-70 U (as VWF:RCof) kg(-1) of a FVIII/VWF concentrate. As local haemostasis is difficult to achieve in bleeding from the tongue or labial or mandibular haematoma, it is necessary to administer 0.4 microg kg(-1) of DDAVP or 60-80 U (as VWF:RCof) kg(-1) of a FVIII/VWF concentrate. In addition, oral administration of 20 mg kg(-1) day(-1) of tranexamic acid should be combined with the regimens described above.     

Radiographic periodontal attachment loss as an indicator of death risk in the elderly

OBJECTIVES: Oral infections have been associated with serious systemic diseases and an increased risk of death. Our aims were to investigate whether radiographically-observed apical periodontitis lesions, carious teeth, periodontal attachment loss (horizontal bone loss, furcation lesions, number of teeth with infrabony periodontal pockets, the extent of infrabony periodontal pockets) and the sum of all these findings have any relationships with all-cause mortality within 4-year follow-up. MATERIAL AND METHODS: 292 community-dwelling elderly persons aged 76, 81 and 86 years. The number of deaths within 4 years was 54 (18.5%). In the dentate 169 subjects, of whom 32 (18.9%) deceased within 4 years, the mean number of teeth was 15.5 in men and 13.2 in women. The imaging method used was panoramic radiography supplemented by intraoral radiographs. RESULTS: 51% of the dentate subjects had infrabony pockets (mean 1.5, s.d. 2.2), and 40% had periapical periodontitis lesions (mean 1.0, s.d. 1.6). After controlling for age and gender, vertical bone loss judged as advanced infrabony pockets was associated with 4-year all-cause mortality (Odds ratio 2.2,1.0-4.7). Other associations were statistically insignificant. CONCLUSION: Periodontal attachment loss may indicate an increased risk of death in the elderly.     

Corrosion resistance of a magnetic stainless steel ion-plated with titanium nitride

This in vitro study evaluated the corrosion resistance of a titanium nitride (TiN) ion-plated magnetic stainless steel (447J1) for the purpose of applying a magnetic attachment system to implant-supported prostheses made of titanium. The surface hardness of the TiN ion-plated 447J1 alloy with varying TiN thickness was determined prior to the corrosion testing, and 2 micrometers thickness was confirmed to be appropriate. Ions released from the 447J1 alloy, TiN ion-plated 447J1 alloy, and titanium into a 2% lactic acid aqueous solution and 0.1 mol/L phosphate buffered saline (PBS) were determined by means of an inductively coupled plasma atomic emission spectroscopy (ICP-AES). Long-term corrosion behaviour was evaluated using a multisweep cyclic voltammetry. The ICP-AES results revealed that the 447J1 alloy released ferric ions into both media, and that the amount of released ions increased when the alloy was coupled with titanium. Although both titanium and the TiN-plated 447J1 alloy released titanium ions into lactic acid solution, ferric and chromium ions were not released from the alloy specimen for all conditions. Cyclic voltamograms indicated that the long-term corrosion resistance of the 447J1 alloy was considerably improved by ion-plating with TiN.     

Surface characterization of retrieved NiTi orthodontic archwires

The structure and morphological condition of retrieved NiTi orthodontic archwires was evaluated and any possible alterations in the surface composition of the alloy following 1-6 months in vivo were characterized. NiTi wires (GAC, German Orthodontics, ORMCO) of various cross-sections were collected through a retrieval protocol and were subjected to multi-technique characterization. Optical microscopy revealed islands of amorphous precipitants and accumulated microcrystalline particles. Micro MIR-FTIR investigation of the retrieved samples demonstrated the presence of a proteinaceous biofilm, the organic constituents of which were mainly amide, alcohol, and carbonate. Scanning electron microscope and X-ray microanalysis showed that the elemental species precipitated on the material surface were Na, K, Cl, Ca, and P, forming NaCl, KCl, and Ca-P precipitates. Increased intra-oral exposure was consistently associated with the presence of a mature film, while evidence of alloy delamination, pitting, and crevice corrosion, as well as a notable reduction in the alloy grain size was observed. Intra-oral exposure of NiTi wires alters the topography and structure of the alloy surface through surface attack in the form of pitting or crevice corrosion or formation of integuments. Further in vivo research is required to resolve the implications of the described ageing pattern in the corrosion resistance of the alloy, the potential for nickel leaching, as well as bracket-archwire friction variants.     

Mental nerve neuropathy as a result of primary herpes simplex virus infection in the oral cavity. A case report

We describe a 25-year-old woman who had mental nerve neuropathy. The symptom was attributed to herpes simplex virus infection, which appeared as herpetic gingivostomatitis 4 days after the extraction of the lower third molar. This case suggests that herpes simplex virus can infect the inferior alveolar nerve through an extraction wound and can induce mental nerve neuropathy.     

Coptidis rhizoma inhibits growth and proteases of oral bacteria

OBJECTIVE: The aim of this study was to investigate the antibacterial effect of Coptidis Rhizoma (CR), a traditional medicinal plant, on oral bacteria. MATERIALS AND METHODS: CR extract was prepared by boiling CR in water for 2 h. Alkaloids contained in CR extract were assayed by high performance liquid chromatography (HPLC). Antibacterial activity of CR extract was estimated from the lowest concentration that did not permit bacterial growth (minimum inhibitory concentration, MIC) and the concentrations that inhibited 50% of bacterial proteolytic activity (IC50). RESULTS: CR extract inhibited the growth of Actinomyces naeslundii, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens and Actinobacillus actinomycetemcomitans at MIC of 0.031-0.25 mg ml(-1), whereas it had less inhibitory effect (MIC: 0.5-2 mg ml(-1)) on the growth of Streptococcus and Lactobacillus. The major active component of CR extract was berberine (Ber), an alkaloid, and its inhibiting specificity to bacterial growth was similar to that of CR extract. CR extract and Ber were bacteriostatic at the MICs against most of the bacteria, and bacteriocidal at the concentrations higher than the MICs. Ber inhibited the activities of collagenase from P. gingivalis and A. actinomycetemcomitans. CONCLUSION: CR extract and Ber had an inhibitory effect on periodontopathogenic bacteria. These results suggest the possibility of their clinical application for the treatment of periodontal diseases.     

Nasalance score variation in normal adult Japanese speakers of Mid-West Japanese dialect.

OBJECTIVE: The aims of this study were to examine nasalance score variation for normal adult Japanese speakers of Mid-West dialect and the gender difference in average mean nasalance score. DESIGN: Nasalance scores were obtained using a nasometer model 6200. The sample stimulus "Kitsutsuki passage," constructed of four sentences containing no Japanese nasal sounds, was used three times by each subject. PARTICIPANTS: One hundred normal adult speakers (50 women and 50 men) of Japanese served as subjects. The subjects ranged in age from 19 to 35 years of age (24.0 +/- 3.2). MAIN OUTCOME MEASURE: A mean nasalance score as well as an overall average nasalance value across speakers was calculated for each subject. The average mean nasalance scores between men and women were compared. RESULTS: The average mean nasalance score for the normal Japanese speakers was 9.1% (+/- 3.9). There was no statistically significant sex difference (p < .01). Average mean scores of 9.8% (+/- 3.5) and 8.3% (+/- 4.0) were obtained for the female and male speakers, respectively. CONCLUSIONS: The results provide important information concerning criteria to evaluate hypernasal speech due to velopharyngeal inadequacy of Japanese speakers with cleft palate using the nasometer.