Design and Initial Evaluation of a Novel Oral Hygiene Technology for a Special Needs Population: A New Way to Clean

9.4 million People have swallowing problems in the US. In special needs populations, routine oral hygiene procedures such as tooth brushing can result in aspiration of microbial laden fluids leading to a significant systemic challenge. Aspiration may lead to pneumonia in susceptible populations. These circumstances indicate the need for innovative approaches to oral hygiene for special needs, convalescent, the elderly populations, and young children learning to brush who can ingest excess fluoride which causes mottled enamel. Methods include describing some of the design considerations of the new prototype fabrication and microbiological evaluation of this new device, as well a comparison study of the versions 2 and 3 of the oral care device. Results concluded that version 3.0 regarding patient ease of use was better in comparison to version 2, which was the major difference, and 90% in both groups said they would recommend the new toothbrush. In the microbiological evaluation no growth was seen on any plates containing samples from either the experimental or the control after 48 h of incubation.

OVER THE COUNTER ANALGESICS ARE EFFECTIVE IN TREATING ORTHODONTIC PAIN

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

The efficacy of analgesics in controlling orthodontic pain: a systematic review and meta- analysis. Cheng C, Xie T, Wang J. BMC Oral Health 2020; 20:259.

SOURCE OF FUNDING

The systematic review was funded by grants from the National Natural Science Foundation of China (No. 81771114 and No. 81970967). The authors have no actual or potential conflicts of interest.

TYPE OF STUDY/DESIGN

Systematic review with meta-analysis of data.

Alternative Antibiotics in Dentistry: Antimicrobial Peptides

The rise of antibiotic resistant bacteria due to overuse and misuse of antibiotics in medicine and dentistry is a growing concern. New approaches are needed to combat antibiotic resistant (AR) bacterial infections. There are a number of methods available and in development to address AR infections. Dentists conventionally use chemicals such as chlorohexidine and calcium hydroxide to kill oral bacteria, with many groups recently developing more biocompatible antimicrobial peptides (AMPs) for use in the oral cavity. AMPs are promising candidates in the treatment of (oral) infections. Also known as host defense peptides, AMPs have been isolated from animals across all kingdoms of life and play an integral role in the innate immunity of both prokaryotic and eukaryotic organisms by responding to pathogens. Despite progress over the last four decades, there are only a few AMPs approved for clinical use. This review summarizes an Introduction to Oral Microbiome and Oral Infections, Traditional Antibiotics and Alternatives & Antimicrobial Peptides. There is a focus on cationic AMP characteristics and mechanisms of actions, and an overview of animal-derived natural and synthetic AMPs, as well as observed microbial resistance.

Differential effects of antiseptic mouth rinses on SARS-CoV-2 infectivity in vitro

SARS-CoV-2 is detectable in saliva from asymptomatic individuals, suggesting a potential benefit from the use of mouth rinses to suppress viral load and reduce virus spread. Published studies on reduction of SARS-CoV-2-induced cytotoxic effects by antiseptics do not exclude antiseptic-associated cytotoxicity. Here, we determined the effect of commercially available mouth rinses and antiseptic povidone-iodine on the infectivity of SARS-CoV-2 virus and of a non-pathogenic, recombinant, SARS-CoV-2 infection vector (pseudotyped SARS-CoV-2 virus). We first determined the effect of mouth rinses on cell viability to ensure that antiviral activity was not a consequence of mouth rinse-induced cytotoxicity. Colgate Peroxyl (hydrogen peroxide) exhibited the most cytotoxicity, followed by povidone-iodine, chlorhexidine gluconate (CHG), and Listerine (essential oils and alcohol). Potent anti-viral activities of povidone iodine and Colgate peroxyl mouth rinses was the consequence of rinse-mediated cellular damage. The potency of CHG was greater when the product was not washed off after virus attachment, suggesting that the prolonged effect of mouth rinses on cells impacts anti-viral activity. To minimalize mouth rinse-associated cytotoxicity, mouth rinse was largely removed from treated-viruses by centrifugation prior to infection of cells. A 5% (v/v) dilution of Colgate Peroxyl or povidone-iodine completely blocked viral infectivity. A similar 5% (v/v) dilution of Listerine or CHG had a moderate suppressive effect on the virus, but a 50% (v/v) dilution of Listerine or CHG blocked viral infectivity completely. Prolonged incubation of virus with mouth rinses was not required for viral inactivation. Our results indicate that mouth rinses can significantly reduce virus infectivity, suggesting a potential benefit for reducing SARS-CoV-2 spread.

Dental products and evidence-based dentistry

Dentists make frequent product recommendations to their patients. Many dental products are intended to exert a therapeutic action such as caries prevention or desensitization. The purpose of this article is to highlight the contributions the principles of evidence-based dentistry (EBD) can make in guiding therapeutic product recommendations. Dental practitioners are exposed to product claims in advertising and in the professional literature. All studies are not equivalent in making treatment decisions. Although useful for screening active ingredients and providing other background information, laboratory studies should not directly inform clinical decision-making. Properly designed and conducted randomized controlled clinical trials assess the impact of an intervention on a disease-relevant outcome measure (like pain scores or periodontal pocket depth). Where available, systematic reviews can help clinicians determine if there are trends and agreement in clinical trial results. Clinical studies need to be evaluated for publication and other forms of bias. In order to use study results in clinical decision-making, the clinical significance of the trial results must be considered. Determining that a result is statistically significant is inadequate since it does not inform the clinician of the magnitude of the treatment effect. Although clinical studies may generate observations that are valid for the conditions and selected population that was used in the trial, the results may not predict how well an intervention will work in actual use by a diverse group of consumers. In order to better inform clinical judgment, practice-based research networks examine the effectiveness of interventions under real-world circumstances. Applying these basic EBD principles should allow dental practitioners to use consumer products to promote oral health.

Assessing the Appearance and Fluorescence of Resin-Infiltrated White Spot Lesions With Caries Detection Devices

OBJECTIVE

This in vitro study examined the effectiveness of caries detector devices in assessing the ability of resin infiltration (RI) (Icon, DMG-Hamburg, Hamburg, Germany) to improve the optical properties of enamel white spot lesions (WSLs).

METHODS AND MATERIALS

Ten caries-free third molars were used. Photographs, a subjective visual assessment of the photographs, fluorescent camera (FC) images using the Spectra (Air Techniques, Melville, NY, USA), and laser fluorescent (LF) readings using the DIAGNOdent (KaVo, Biberach, Germany) were obtained from each tooth's buccal surface. Specimens were coated with nail polish leaving a rectangular window on the buccal surface and placed in pH 4.5 lactic acid gel for two weeks to create a WSL. The WSLs were analyzed by the same methods. RI was applied to half of each WSL; final photographs were then taken, and caries detector assessments were conducted. FC images were converted to grayscale, and the fluorescent image's brightness intensity was measured using ImageJ. Data were analyzed with analysis of variance and Tukey-Kramer honestly significant difference test. Significance was set at α=0.05.

RESULTS

Subjective assessment of the photographs showed that RI improved the appearance of the WSLs so that they resembled intact enamel. Mean FC-brightness intensities for intact, demineralized, and demineralized RI-treated areas were 159.6 ± 9.2, 123.4 ± 7.2, and 160.9 ± 11.5, respectively. There were no significant differences in fluorescent intensity between the intact and RI areas ( p=0.58). The demineralized areas had significantly lower fluorescent intensity than both the RI-treated and intact areas ( p<0.001). LF values did not differ significantly between intact, demineralized, or RI-treated areas.

CONCLUSIONS

This study demonstrates the ability of RI to restore artificial WSLs to the esthetics and fluorescence of intact enamel. The FC can be used to assess the optical properties of WSLs and the impact of RI on these properties.

The clinical performance of chairside caries risk assessment kits

OBJECTIVE

Caries risk assessment is an important component of clinical practice. The goal of this project was to evaluate the diagnostic performance of two commercially available kits (the Saliva-Check mutans and the Plaque-Check pH kit; GC-America) in distinguishing caries-active from caries-free individuals. The effect of following instructions not to eat, drink, or perform oral hygiene, prior to testing, was also investigated on the effectiveness of these kits.

METHOD AND MATERIALS

The subjects included 26 caries-affected children and 20 caries-free adults. Plaque and saliva samples were collected for analysis by the two kits following the manufacturer's instructions. For 63 additional subjects, instructions not to eat, drink, or practice oral hygiene were omitted prior to sample collection. The sensitivity and specificity in distinguishing caries-free from caries-active subjects was calculated for both kits.

RESULTS

The sensitivity (88%) and specificity (90%) of the Saliva-Check mutans kits were satisfactory in the subjects refraining from eating etc. In contrast, both the sensitivity and the specificity of this kit were reduced when subjects were tested without use instructions. When tested in subjects that followed instructions, the pH kit's sensitivity and specificity were 72% and 55% respectively. This modest diagnostic performance was reduced when pH values were measured in subjects not following use instructions.

CONCLUSION

These kits, particularly the Saliva-Check mutans kits, can contribute to patient education by documenting microbial caries risk factors. Though difficult to implement in practice, subjects should refrain from eating or other activities that disturb the oral environment prior to sample collection.

Diabetic Lactoferrin Deficient Mice Demonstrates Greater Susceptibility to Experimental Periodontal Disease

The objective of this study is to detrmine whether alloxan-induced diabetic Lactoferrin knockout (LFKO^-/-) mice are more susceptible to periodontal disease caused by Aggregatibacter actinomycetemcomitans compared to the diabetic wild-type (WT) mice. Diabetes was induced in mice by a single dose of alloxan (60 mg/kg) injected intravenously. Mice were categorized as diabetic when blood glucose levels >250 mg/dL were measured on the 7^th day after the injection. Periodontal disease was experimentally induced by A. actinomycetemcomitans infection in alloxan induced diabetic WT and LFKO^-/- mice. Fasting blood glucose levels and body weight were monitored throughout the study. At the end of the 12^th week of infection, mice were sacrificed and bone loss among the groups was estimated by measuring the distance between cemento-enamel junction (CEJ) to the alveolar bone crest (ABC) at 12 sites on the molars. A. actinomycetemcomitans infected mice groups developed more alveolar bone loss than sham-infected animals. Diabetic LFKO^-/- infected mice exhibited significant bone loss (P<0.01) and a higher mean fasting blood glucose level (P<0.05) when compared to diabetic WT infected mice. No statistically significant difference in fasting blood glucose level was found between the infected and sham-infected groups. Peripheral blood analysis at the end of the 12^th week revealed a significant reduction in the platelet counts in LFKO^-/- mice when compared to WT mice. Furthermore, diabetic LFKO^-/- presented with lower counts than non-diabetic LFKO^-/- mice (P<0.01). In conclusion, diabetic lactoferrin deficient mice are at a higher risk of developing periodontal infection induced by A. actinomycetemcomitans when compared to diabetic WTI mice.

In vitro study of the diagnostic performance of the Spectra Caries Detection Aid

OBJECTIVE

The Spectra Caries Detection Aid is a fluorescent camera (FC) caries detector device that has been demonstrated to detect occlusal caries extending into dentin with good sensitivity and specificity. This in vitro study examined the diagnostic performance of this device with the goal of defining the numerical reading that best indicates that a tooth has dentin caries.

METHODS

Ninety extracted human third molars, that either appeared clinically intact or had early occlusal caries, were used. Teeth were photographed then analyzed using the Spectra Caries detector. Following Spectra readings, the teeth were sectioned perpendicular to the long axis of the tooth. Cuts were made in such a way as to expose the dentino-enamel junction below the pits and fissures. The sectioned teeth were scored as being caries-free, having enamel caries, or dentin caries. Using each tooth's Spectra reading and histological diagnosis, the sensitivity and specificity for various potential dentin caries cut-off values were calculated. Also, the receiver operator curve (ROC) was plotted and the area under the curve calculated.

RESULTS

At the manufacture's recommended cut-off for dentin caries diagnosis of 2, the sensitivity is 0.68 and the specificity is 0.78. At a lower cut-off value in the study reported here of 1.8, it was observed that the sensitivity is higher at 0.87, but that the specificity is lower at 0.7. The overall diagnostic performance of the Spectra is good with an ROC area under the curve of 0.82.

CONCLUSION

Although lower cut-off values may have higher sensitivity, the use of the manufacture's established cut-off of 2 will result in fewer instances where dentin caries will be diagnosed incorrectly. The use of higher thresholds will discourage restorative treatment of early lesions that are best managed by sealants or other preventive approaches.

Oral lactoferrin protects against experimental candidiasis in mice

AIMS

To determine the role of human lactoferrin (hLF) in protecting the oral cavities of mice against Candida albicans infection in lactoferrin knockout (LFKO(-/-)) mice was compared to wild-type (WT) mice. We also aim to determine the protective role of hLF in LFKO(-/-) mice.

METHODS AND RESULTS

Antibiotic-treated immunosuppressed mice were inoculated with C. albicans (or sham infection) by oral swab and evaluated for the severity of infection after 7 days of infection. To determine the protective role of hLF, we added 0·3% solution of hLF to the drinking water given to some of the mice. CFU count, scoring of lesions and microscopic observations were carried out to determine the severity of infection. LFKO(-/-) I mice showed a 2 log (P = 0·001) higher CFUs of C. albicans in the oral cavity compared to the WT mice infected with C. albicans (WTI). LFKO(-/-) I mice given hLF had a 3 log (P = 0·001) reduction in CFUs in the oral cavity compared to untreated LFKO(-/-) I mice. The severity of infection, observed by light microscopy, revealed that the tongue of the LFKO(-/-) I mice showed more white patches compared to WTI and LFKO(-/-) I + hLF mice. Scanning electron microscopic observations revealed that more filiform papillae were destroyed in LFKO(-/-) I mice when compared to WTI or LFKO(-/-) I + hLF mice.

CONCLUSIONS

Human LF is important in protecting mice from oral C. albicans infection. Administered hLF may be used to prevent C. albicans infection.

SIGNIFICANCE AND IMPACT OF THE STUDY

Human LF, a multifunctional iron-binding glycoprotein can be used as a therapeutic active ingredient in oral healthcare products against C. albicans.

Macrophage inflammatory protein-1α shows predictive value as a risk marker for subjects and sites vulnerable to bone loss in a longitudinal model of aggressive periodontitis

Improved diagnostics remains a fundamental goal of biomedical research. This study was designed to assess cytokine biomarkers that could predict bone loss (BL) in localized aggressive periodontitis. 2,058 adolescents were screened. Two groups of 50 periodontally healthy adolescents were enrolled in the longitudinal study. One group had Aggregatibacter actinomycetemcomitans (Aa), the putative pathogen, while the matched cohort did not. Cytokine levels were assessed in saliva and gingival crevicular fluid (GCF). Participants were sampled, examined, and radiographed every 6 months for 2-3 years. Disease was defined as radiographic evidence of BL. Saliva and GCF was collected at each visit, frozen, and then tested retrospectively after detection of BL. Sixteen subjects with Aa developed BL. Saliva from Aa-positive and Aa-negative healthy subjects was compared to subjects who developed BL. GCF was collected from 16 subjects with BL and from another 38 subjects who remained healthy. GCF from BL sites in the 16 subjects was compared to healthy sites in these same subjects and to healthy sites in subjects who remained healthy. Results showed that cytokines in saliva associated with acute inflammation were elevated in subjects who developed BL (i.e., MIP-1α MIP-1β IL-α, IL-1β and IL-8; p<0.01). MIP-1α was elevated 13-fold, 6 months prior to BL. When MIP-1α levels were set at 40 pg/ml, 98% of healthy sites were below that level (Specificity); whereas, 93% of sites with BL were higher (Sensitivity), with comparable Predictive Values of 98%; p<0.0001; 95% C.I. = 42.5-52.7). MIP-1α consistently showed elevated levels as a biomarker for BL in both saliva and GCF, 6 months prior to BL. MIP-1α continues to demonstrate its strong candidacy as a diagnostic biomarker for both subject and site vulnerability to BL.

An overview of children's oral health-related quality of life assessment: from scale development to measuring outcomes

The objectives of this paper are to present an overview of children's oral health-related quality of life and include specific applications for using quality of life assessment in dental research. The process of developing pediatric oral health- related quality of life measures, in particular the Child Oral Health Impact Profile, is outlined. Examples of children's oral health-related quality of life measurement in caries research are also provided. Quality of life outcomes are presented and discussed in the context of caries research. Lastly, the relevance of measuring clinically meaningful difference in the context of measuring outcomes research is highlighted with recommendations for future research.

Effect of pit and fissure sealants on caries detection by a fluorescent camera system

OBJECTIVE

The aim of this study was to evaluate the effect of sealant placement on the detection of caries by a fluorescent camera (FC), the Spectra caries detector.

MATERIALS AND METHODS

In a laboratory study, FC images and readings were obtained from 31 extracted teeth, before and following application of clear sealants (Shofu Clear or Delton unfilled), or opaque sealants (3M Clinpro or Delton FS). Teeth were then sectioned and examined for enamel or dentine caries. Using each tooth's true caries diagnosis, the sensitivity and specificity of the FC measurements in detecting dentine caries was calculated. In the clinical study, FC readings were obtained from 41 molars in children prior to and following application of clear sealants.

RESULTS

Following application of Shofu or Delton unfilled there were reductions in the mean FC readings of 10% (p=0.5) and 8.2% (p=0.009), respectively. Application of two opaque sealants, 3M or Delton FS significantly reduced mean FC readings 16.2% and 20.8% (p<0.5), respectively. Although the carious lesions could still be observed in FC images from teeth with opaque sealants there was a significant loss of sensitivity in detecting dentinal caries. Clear sealant application caused an insignificant loss of detection sensitivity. Following application of clear sealants to children's molars there was a small (4.01%) but significant (p<0.01) reduction in FC readings recorded from these teeth.

CONCLUSIONS

The FC can detect caries under clear sealants with little loss of sensitivity. Although lesions can be seen through opaque sealants, loss of sensitivity precludes accurate lesion assessment.

Lactoferrin knockout mice demonstrates greater susceptibility to Aggregatibacter actinomycetemcomitans-induced periodontal disease

BACKGROUND

Among the innate defense mechanisms in the oral cavity, lactoferrin (LF) is a vital antimicrobial that can modify the host response against periodontopathogens. Aggregatibacter actinomycetemcomitans is the main periodontopathogen of localized aggressive periodontitis. The aim of this study is to evaluate the role of LF during A. actinomycetemcomitans-induced periodontitis.

METHODS

Differences in the expression levels of cytokines, chemokines, chemokine receptors, and bone loss markers between wild-type (WT) and LF knockout mice (LFKO(-/-)) were evaluated by real time-PCR. Serum IgG and LF levels were quantified by ELISA. Alveolar bone loss among the groups was estimated by measuring the distance from cemento-enamel junction (CEJ) to the alveolar bone crest (ABC) at 20 molar sites.

RESULTS

Oral infection with A. actinomycetemcomitans increased LF levels in periodontal tissue (P = 0.01) and saliva (P = 0.0004) of wild-type infected (WTI) mice compared to wild-type control mice. Pro-inflammatory cytokines such as interferon-γ, tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-12 were increased in the infected LF knockout (LFKO(-/-)I) mice compared to the WTI mice, whereas the anti-inflammatory cytokines IL-4 and IL-10 were decreased. Chemokines and chemokine receptors showed different expression patterns between WTI and LFKO(-/-)I mice. The LFKO(-/-)I mice developed increased bone loss (P = 0.002), in conjunction with increased expression of receptor activator of nuclear factor-κB ligand and decrease in osteoprotegerin, compared to WTI mice.

CONCLUSIONS

These results demonstrate that the infected LFKO(-/-) mice were more susceptible to A. actinomycetemcomitans-induced alveolar bone loss, with different patterns of immune responses compared to those of WTI mice.

A longitudinal study of occlusal caries in Newark New Jersey school children: relationship between initial dental finding and the development of new lesions

OBJECTIVE

Dental caries is a significant public health problem especially amongst children from low-income backgrounds. This longitudinal study examined the development of new occlusal caries in 227 Newark, NJ children ages 10-18. The role of previous caries experience and the presence of occlusal white and dark lesions in predicting the development of new lesions were examined.

DESIGN

At each visit, the patient's teeth were given a visual-tactile examination and the subject's decayed, missing and filled (DMFS) score was determined. Next, molars lacking probeable caries or restorations were examined using transillumination for occlusal white and dark spots. This examination was repeated periodically. A Cox proportional hazard was used to analyse data concerning the development of new occusal caries in molars.

RESULTS

The longitudinal data indicates that patients who were caries free at visit-1 developed significantly fewer occlusal caries during the longitudinal study. The hazard ratio for subjects who had first-visit caries was 2.27 compared to caries free subjects. Intact molars with occlusal white or dark lesions had caries hazard ratios of 0.78 and 1.49 respectively, compared to molars lacking initial colour changes.

CONCLUSION

Having a prior caries history places the subject at increased risk of developing future caries. Teeth with dark lesions but not white lesions are at significantly increased risk for developing decay. White lesions may represent remineralizing or slowly progressing lesions. The results of this study can help identify patients and tooth surfaces at risk for future occlusal decay.

In vitro evaluation of the Spectra early caries detection system

OBJECTIVE

The goal of this study was to perform an in vitro evaluation of the Spectra, a new caries detector that uses light-induced fluorescence of healthy tooth structure and bacterial pigments to optically detect caries. The Spectra generates a storable color map image of examined tooth surfaces which shows areas of enamel and dentin caries. In this study, Spectra readings of occlusal surfaces were compared to clinical, radiographic, and histological assessments of caries.

METHODS

Two examiners evaluated 41 extracted molars. The teeth were radiographed and then visually assessed. The International Caries Detection and Assessment System (ICDAS) was used to classify the extent of caries. The teeth were then sectioned and assigned a histological score based on the extension of caries into enamel or dentin.

RESULTS

Teeth lacking radiographic caries had a mean Spectra reading of 1.5. Teeth having radiographic caries had a mean Spectra reading of 2.0. This difference was statistically significant. In general, higher ICDAS scores were associated with higher Spectra readings. Teeth with histologically evident deep dentin caries had significantly higher Spectra readings than intact teeth or teeth with superficial enamel demineralization. Spectra assessment of occlusal caries agrees with clinical and radiographic methods.

CONCLUSION

Spectra images illustrate the full spectrum of caries severity, from enamel demineralization to dentin decay. The Spectra is a promising technology for the diagnosis and for monitoring the progression of occlusal caries.

The effect of distance and tooth structure on laser fluorescence caries detection

The DIAGNOdent, a device used in caries detection, uses a laser to excite fluorescence from pigments in carious tooth structure. In clinical use assessing occlusal surfaces, distance and tooth structure may separate the instrument's tip from the fluorescent source.The aim of this in vitro study was to examine the effect of distance and tooth structure on laser fluorescence (LF) readings.In one set of experiments, a porphyrin pigmentin oil suspension was used as a LF signal source. Thin slices of enamel and dentin were obtained from extracted molars. Pigment-induced LF readings were obtained when these slices were placed between the porphyrin pigment and the LF instrument's tip. The effect of either demineralized or intact tooth tissue on pigment-induced LF readings was assessed.In other experiments on extracted molars with small occlusal caries, LF readings were taken from pit/fissure sites before and after removal of the occlusal surface.LF readings are proportional to pigment con-centration and inversely proportional to the distance between the suspension and the instrument's tip. Enamel, demineralized enamel,dentin, and demineralized dentin all caused significant reductions in LF signal, all readings being taken with the same tip-pigment distance. Demineralized enamel (white with intact surface) caused the most reduction.After sectioning of carious teeth, there was a significant increase in LF readings.The results of this study indicate that distance and the presence of tooth structure between the carious lesion and the instrument's tip reduce LF readings. These results indicate that anatomic factors interfere with the LF device's ability to assess occlusal caries. DIAGNOdent readings should not be relied on when making diagnostic decisions.

Activity of antimicrobial peptide mimetics in the oral cavity: I. Activity against biofilms of Candida albicans

Naturally occurring antimicrobial peptides hold promise as therapeutic agents against oral pathogens such as Candida albicans but numerous difficulties have slowed their development. Synthetic, non-peptidic analogs that mimic the properties of these peptides have many advantages and exhibit potent, selective antimicrobial activity. Several series of mimetics (with molecular weight < 1000) were developed and screened against oral Candida strains as a proof-of-principle for their antifungal properties. One phenylalkyne and several arylamide compounds with reduced mammalian cytotoxicities were found to be active against C. albicans. These compounds demonstrated rapid fungicidal activity in liquid culture even in the presence of saliva, and demonstrated synergy with standard antifungal agents. When assayed against biofilms grown on denture acrylic, the compounds exhibited potent fungicidal activity as measured by metabolic and fluorescent viability assays. Repeated passages in sub-minimum inhibitory concentration levels did not lead to resistant Candida, in contrast to fluconazole. Our results demonstrate the proof-of principle for the use of these compounds as anti-Candida agents, and their further testing is warranted as novel anti-Candida therapies.

Aggregatibacter actinomycetemcomitans-induced bone loss and antibody response in three rat strains

BACKGROUND

The aim of this study is to compare the colonization, immunoglobulin (Ig) G response, and alveolar bone loss in Aggregatibacter actinomycetemcomitans (Aa)-inoculated Fawn Hooded Hypertensive (FHH), Dahl Salt-Sensitive (DSS), and Brown Norway (BN) rats.

METHODS

Each rat strain was divided into wild-type Aa-inoculated and non-inoculated control groups. Blood taken at 12 weeks after inoculation was assessed for Aa-specific IgG antibodies by an enzyme-linked immunosorbent assay. Colonization was assessed 12 weeks postinoculation. Bone loss was estimated by measuring the distance from the cemento-enamel junction (CEJ) to the alveolar bone crest (ABC) at 20 molar sites. Colonization and antibody levels were compared by using the Student t test. Diseased rats were defined as having two sites per quadrant with CEJ-ABC distances that were significantly greater than the control CEJ-ABC distances.

RESULTS

The Aa colonization of FHH rats was significantly higher than in other strains (P <0.05). The Aa-specific IgG levels in the DSS Aa-inoculated group were significantly higher than in its control group (P <0.05). Only FHH rats showed Aa disease-associated bone loss (P = 0.0021).

CONCLUSIONS

Aa colonized and caused more disease in FHH rats than in the other rat strains. The rat strains each responded differently to the same Aa strain.

Macrophage inflammatory protein-1alpha: a salivary biomarker of bone loss in a longitudinal cohort study of children at risk for aggressive periodontal disease?

BACKGROUND

Periodontitis develops in a time-dependent manner. Cross-sectional studies document one moment in time but fail to capture the progressive nature of disease. Radiographic measures of bone loss are relatively insensitive but are reliable markers of irreversible disease. Longitudinal studies are needed to identify biomarkers that can precede radiographic evidence of bone loss and, thus, mark the period prior to clinical evidence of irreversible disease. A longitudinal study of students susceptible to localized aggressive periodontitis (LAgP) was conducted to evaluate chemokines/cytokines found in saliva derived from periodontally healthy children who subsequently developed alveolar bone loss.

METHODS

Students were screened, sampled for Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans [Aa]), and divided into a cohort of Aa+ and Aa- students. Ninety-six periodontally healthy Aa+ and Aa- students were recalled every 6 to 9 months following screening. Examinations, saliva collections, and radiographs were performed. After seven students developed bone loss, the levels of 21 cytokines were assessed and matched to saliva from seven Aa+ and seven Aa- students who remained healthy for > or =1 year. Subsequently, saliva from an additional 27 students who remained healthy was analyzed.

RESULTS

Nineteen cytokines were not detected or were detected at low levels. Macrophage inflammatory protein (MIP)-1alpha was elevated 50-fold in seven Aa+ students who developed disease 6 to 9 months prior to radiographic detection of bone loss compared to levels in 21 Aa+ and 20 Aa- students who remained healthy (P <0.001). Interleukin (IL)-1beta was also elevated (P = 0.01). MIP-1alpha had a specificity of 96.8% and a sensitivity of 100%, whereas IL-1beta showed 90.3% specificity and 85.7% sensitivity relative to bone loss. MIP-1alpha levels were also related to increasing probing depth and the number of pockets >6 mm.

CONCLUSION

The superior sensitivity and specificity of MIP-1alpha, which correlated well with probing depths and the onset of bone loss, suggested that it could be used as an early biomarker for LAgP.

An improved cost-effective, reproducible method for evaluation of bone loss in a rodent model

AIM

This study was designed to investigate the utility of two "new" definitions for assessment of bone loss in a rodent model of periodontitis.

MATERIAL AND METHODS

Eighteen rats were divided into three groups. Group 1 was infected by Aggregatibacter actinomycetemcomitans (Aa), group 2 was infected with an Aa leukotoxin knock-out, and group 3 received no Aa (controls). Microbial sampling and antibody titres were determined. Initially, two examiners measured the distance from the cemento-enamel-junction to alveolar bone crest using the three following methods; (1) total area of bone loss by radiograph, (2) linear bone loss by radiograph, (3) a direct visual measurement (DVM) of horizontal bone loss. Two "new" definitions were adopted; (1) any site in infected animals showing bone loss >2 standard deviations above the mean seen at that site in control animals was recorded as bone loss, (2) any animal with two or more sites in any quadrant affected by bone loss was considered as diseased.

RESULTS

Using the "new" definitions both evaluators independently found that infected animals had significantly more disease than controls (DVM system; p<0.05).

CONCLUSIONS

The DVM method provides a simple, cost effective, and reproducible method for studying periodontal disease in rodents.

The original desensitizers: strontium and potassium salts

Many patients complain of teeth that are painful when exposed to a variety of harmless thermal and tactile stimuli. Sensitive tooth necks and root surfaces frequently are the unintentional by-products of aggressive oral hygiene practices and periodontal treatment. Dentists and the afflicted patients have resorted to many remedies for this common form of dental pain. In the past, many of these purported treatments were based on a fragmentary knowledge of the anatomic substrate and physiological processes underlying dentin sensitivity. Much progress has been made identifying dentin permeability and intradental nerve excitability as physiological parameters that can be modified by desensitizing agents. In this paper, rather than provide a comprehensive or critical review of desensitizing treatment, I will discuss the rationale and some of the history behind two early and popular classes of dentifrice-applied desensitizing agents; strontium and potassium salts.

Mechanotransducers in rat pulpal afferents

The hydrodynamic theory suggests that pain associated with stimulation of a sensitive tooth ultimately involves mechanotransduction as a consequence of fluid movement within exposed dentinal tubules. To determine whether putative mechanotransducers could underlie mechanotransduction in pulpal afferents, we used a single-cell PCR approach to screen retrogradely labeled pulpal afferents. The presence of mRNA encoding BNC-1, ASIC3, TRPV4, TRPA1, the alpha, beta, and gamma subunits of ENaC, and the two pore K+ channels (TREK1, TREK2) and TRAAK were screened in pulpal neurons from rats with and without pulpal inflammation. ASIC3, TRPA1, TREK1, and TREK2 were present in approximately 67%, 64%, 14%, and 10% of pulpal neurons, respectively. There was no detectable influence of inflammation on the proportion of neurons expressing these mechanotransducers. Given that the majority of pulpal afferents express ASIC3 and TRPA1, our results raise the possibility that these channels may be novel targets for the treatment of dentin sensitivity.

Effect of an essential oil-containing antimicrobial mouthrinse on specific plaque bacteria in vivo

AIM

This study was conducted to investigate the effect of rinsing with an essential oil-containing mouthrinse on levels of specific supra and subgingival bacteria in subjects with gingivitis.

MATERIAL AND METHODS

Fifteen subjects meeting entry criteria completed this randomized, controlled, double-blind, crossover study. Subjects were required to have >or=1000 target organisms per millilitre in pooled samples from two subgingival sites. Following sampling of supra and subgingival plaque, subjects began twice-daily rinsing for 14 days with either an essential oil-containing mouthrinse (Cool Mint Listerine Antiseptic) or a negative control. Supra and subgingival plaque was again sampled on day 15, and the procedure repeated after a 1-week washout period with subjects using the alternate rinse.

RESULTS

Compared with the negative control, the essential oil mouthrinse produced significant reductions in supragingival plaque levels of Veillonella sp., Capnocytophaga sp., Fusobacterium nucleatum, and total anaerobes ranging from 52.3 to 88.5% (p<0.001 except for Veillonella, p=0.002); respective reductions in subgingival plaque ranged from 54.1 to 69.1% (p<0.001).

CONCLUSIONS

Rinsing with the essential oil mouthrinse can have an impact on the subgingival plaque flora. This study provides additional evidence indicating that reduction in supragingival plaque can reduce levels of subgingival plaque.

The antimicrobial effect of a triclosan/copolymer dentifrice on oral microorganisms in vivo

BACKGROUND

The authors compared the in vivo antimicrobial effects on microorganisms from dental plaque, saliva and the tongue in subjects who used a triclosan/copolymer dentifrice and a fluoride dentifrice (control).

METHODS

The authors assigned 15 subjects randomly to the control dentifrice or the triclosan/copolymer dentifrice for twice-daily use for one week. They collected samples of plaque, saliva and tongue scrapings six and 12 hours after the final brushing. They analyzed colony-forming units of Veillonella species, Fusobacteria species, total cultivable anaerobes and hydrogen sulfide (H(2)S)-producing bacteria. A one-week washout followed. The authors repeated the protocol with the second dentifrice.

RESULTS

The results showed no differences at baseline. Significant reductions (88 to 96 percent) in oral anaerobic bacteria were observed in the triclosan/copolymer group six and 12 hours after brushing compared with the control group (P = .001). Fusobacteria decreased by 77 to 92 percent and Veillonella decreased by 84 to 89 percent six and 12 hours after brushing in the triclosan/copolymer group versus the control group. The triclosan/copolymer group also demonstrated a significant decrease in H(2)S-producing bacteria six and 12 hours after brushing (74 to 85 percent) (P = .001).

CONCLUSIONS

Brushing with the triclosan/copolymer dentifrice resulted in significant reductions in microorganisms from the three sites compared with the control dentifrice.

CLINICAL IMPLICATIONS

The triclosan/copolymer dentifrice produced sustained effects on oral bacteria for 12 hours.

Tooth sensitivity: mechanisms and management

Tooth sensitivity is a common complaint encountered in clinical practice. Exposed superficial dentin is free of nerve endings, yet sensitive. Experimental evidence indicates that stimuli, such as probing the dentin surface and air blasts, induce fluid movements in the dentinal tubules and these fluid movements, in turn, activate the intradental nerves. The condition of the dentin surface is critically important in allowing this process. In addition, the internal environment of the pulp may influence nerve excitability. Therapies for tooth sensitivity include both agents that obstruct the dentinal tubules and agents that can decrease the excitability of the intradental nerves. The exact treatment used depends on the etiology of the individual's problem and the extent of dentinal tissue damage.

Effects of capsaicin on KCl-induced blood flow and sensory nerve activity changes in the tooth pulp

Potassium ion-containing solutions have been shown to initially excite then depress intradental nerve activity (INA) when applied into deep dentinal cavities. The INA reflects activity originating in intradental A fibers. Application of KCl to deep dentinal cavities also induces an increase in pulpal blood flow (PBF). Capsaicin is known to exert a highly selective desensitizing effect on polymodal C-fiber nerve endings. These C fibers are generally believed to release vasoactive substances in response to stimulation. In order to determine if KCl exerts its vascular effect via activation of capsaicin-sensitive nerve fibers, we examined blood flow and sensory nerve responses to KCl obtained before and after capsaicin desensitization. The A-fiber nerve activity was determined by using INA recording technique. Blood flow was measured simultaneously from the same tooth using laser Doppler flowmetry. Local application of 0.25 M KCl to a deep dentinal cavity induced a brief spike burst and an increase in PBF of 76.0 +/- 14.6% (n = 8). Repeated applications of 0.25 M KCl caused a consistent increase in the peak PBF amplitude (n = 8). Local application of 100 microM capsaicin to a deep dentinal cavity caused an increase in PBF of 116.8 +/- 26.3% (n = 8) lasting 12-18 min, but capsaicin application did not appear to evoke any INA response. The amplitude of PBF in response to capsaicin application declined during repeated applications. Following repeated applications of capsaicin the PBF response to KCl was significantly reduced (9.9 +/- 4.3%, n = 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Biologic properties of eugenol and zinc oxide-eugenol. A clinically oriented review

Eugenol-containing dental materials are frequently used in clinical dentistry. When zinc oxide-eugenol (ZOE) is applied to a dentinal cavity, small quantities of eugenol diffuse through the dentin to the pulp. Low concentrations of eugenol exert anti-inflammatory and local anesthetic effects on the dental pulp. Thus use of ZOE temporary filling may facilitate pulpal healing; on the other hand, high eugenol concentrations are cytotoxic. Direct application of eugenol to pulp tissue may result in extensive tissue damage. The ability of ZOE-based endodontic sealers to influence periapical tissue healing is considered in view of eugenol's anti-inflammatory and toxic properties.

Decreasing intradental nerve activity in the cat with potassium and divalent cations

Nerve activity was recorded from deep dentinal cavities in the canine teeth to assess the possible influence of potassium and divalent cations in decreasing this activity in hypersensitive teeth. The decreased activity after the topical application of 0.756 mol/l KCl to the cavity was primarily due to the cation. KCl elicited a biphasic response from intradental nerves, an initial transient excitatory response followed by a prolonged inhibitory period. During the inhibitory period 3 mol/l NaCl, an effective excitatory stimulus, failed to evoke intradental nerve activity. However, with time the response to 3 mol/l NaCl eventually recovered to its previous control level. Close, intra-arterial injection of KCl showed the same biphasic response and time-course of intradental nerve activity as with topical application. Therefore, whether KCl was applied topically or injected its effectiveness in altering the nerve activity was similar. Pretreatment of the dentinal cavity with CaCl2, MgCl2 or SrCl2 greatly reduced the response of intradental nerves to KCl. Therefore these divalent cations seem to have a depressant action on pulpal nerve fibres. The mechanism of action of KCl seems to be an alteration of K+ concentration immediately surrounding the intradental nerves which presumably depolarizes the nerve fibre membrane and elicits an initial firing of action potentials. Because of the persisting high levels of extracellular potassium a sustained depolarized state occurs that results in an inactivation of the action potential. Divalent cations appear to depress the excitability of the nerve cell membrane without altering membrane potential. Such ionic agents could be used in conjunction with KCl as a possible treatment for hypersensitive teeth.

Hypersensitive teeth. Experimental studies of dentinal desensitizing agents

The effect of dentinal desensitizing agents on nerve activity was tested. Effective agents such as KNO3 reduce dentinal sensory nerve activity. This effect is due to the depolarizing action of the K+ ion.

Comparison of pulpal blood flow in dog canine teeth determined by the laser Doppler and the 133xenon washout methods

Pulpal blood flow measurements by laser Doppler flowmetry were compared with those made simultaneously and on the same teeth by the 133Xe washout method. Pulpal method flow in the resting state was 82.4 ml/min per 100 g as calculated from the fast component of the 133Xe washout, whereas laser Doppler flowmetry recorded 263 mV. The close intra-arterial (i.a.) injection of the vasoconstrictor norepinephrine (10(-2)-10(-1) micrograms/kg) caused a reduction of pulpal blood flow by 20.2% with the 133Xe washout and by 9.7% with the laser Doppler flowmetry in 6 observations in 4 dogs. The laser Doppler flowmetry measurements of these norepinephrine-induced changes correlated significantly with changes measured by the 133Xe washout method as analysed by linear regression (p = 0.004).

Comparison of the effects of intra-arterial and locally applied vasoactive agents on pulpal blood flow in dog canine teeth determined by laser Doppler velocimetry

The vasoactive agents norepinephrine, 5-hydroxytryptamine, isoproterenol and bradykinin, at concentrations which changed local arterial pressure without changing systemic arterial pressure significantly, were injected intra-arterially (i.a.) into the maxillary artery or applied directly in a deep dentinal cavity on the buccal surface of canine teeth. The probe of a laser Doppler velocimeter was placed in the cavity to monitor pulpal blood flow. Bolus i.a. injections of the vasoconstrictors norepinephrine and 5-hydroxytryptamine produced a statistically significant (p less than 0.05) reduction in pulpal blood flow, 21.1 +/- 3.7 and 30.7 +/- 15.2%, and the local arterial pressure from the lateral nasal artery increased with norepinephrine but decreased with 5-hydroxytryptamine. The i.a. injections of the vasodilators isoproterenol and bradykinin were found to decrease both local arterial pressure and pulpal blood flow, 17.7 +/- 6.0 and 22.7 +/- 4.2%, respectively (p less than 0.05). However, local application of isoproterenol and bradykinin caused a biphasic response: an increase in pulpal blood flow, 8.6 +/- 1.6 and 9.4 +/- 1.1% (p less than 0.05), followed by a decrease, 19.1 +/- 11.9 and 5.3 +/- 2.1% (p greater than 0.005). Local application of norepinephrine and 5-hydroxytryptamine caused a decrease in pulpal blood flow, 23.7 +/- 5.2% (p less than 0.05) and 9.3 +/- 5.2% (p less than 0.05), respectively. These findings were in accordance with those from other reliable methods, such as injections of radioisotope-labelled 15 microns microspheres and the 133Xe washout technique, making laser Doppler flowmetry a reliable alternative. In addition, the biphasic response to the locally applied vasodilators and the reduction of pulpal blood flow after i.a. injection of vasodilators suggest that regulation of pulpal blood flow is determined by the combined effects of the low compliance environment and the stealing of perfusion to the pulp by the neighbouring tissues.

Effects of ionic and non-ionic solutions on intradental nerve activity in the cat

Intradental nerve activity (INA) was recorded from cat canine teeth to determine whether solutions altering intradental nerve sensitivity were strongly correlated to the osmotic concentration of the solution or via a more direct action on intradental nerve excitability. The effects of various ionic and non-ionic solutions were tested in both deep and shallow dentinal cavities. With saline in the deep dentinal cavity a very low firing rate or resting nerve spike (action potentials) activity was recorded. When 3 M NaCl was placed in the same or similar cavity a high discharge rate of nerve spike activity was obtained. This 3 M NaCl elicited activity was utilized to determine the inhibitory or excitatory effects of various test agents on the intradental nerves. The following agents: MgCl2, MgSO4, and CaCl2 were inhibitory to the INA response elicited by 3 M NaCl. Non-ionic solutions of urea or sucrose failed to evoke INA and they were also minimally effective in altering 3 M NaCl elicited activity. Shallow cavities were utilized to maintain the tubular structure of dentin relatively intact. In the shallow cavity preparations hypertonic sucrose or urea failed to evoke INA, even when dentin was etched with 50% citric acid for 2 min. The results suggest that the osmolarity of these solutions is a poor indicator of the INA.