Defining Metaniches in the Oral Cavity According to Their Microbial Composition and Cytokine Profile.

The human oral microbiota consists of over 700 widespread taxa colonizing the oral cavity in several anatomically diverse oral niches. Lately, sequencing of the 16S rRNA genes has become an acknowledged, culture-independent method to characterize the oral microbiota. However, only a small amount of data are available concerning microbial differences between oral niches in periodontal health and disease. In the context of periodontitis, the cytokine expression in the gingival crevicular fluid has been studied in detail, whereas little is known about the cytokine profile in hard and soft tissue biofilms. In order to characterize oral niches in periodontal health, the oral microbiota and cytokine pattern were analyzed at seven different sites (plaque (P), gingival crevicular fluid (GCF), saliva (S), tongue (T), hard palate (HP), cheek (C) and sublingual area (U)) of 20 young adults using next-generation sequencing and multiplex immunoassays. Site-specific microbial compositions were detected, which clustered into three distinct metaniches ("P-GCF", "S-T-HP" and "C-U") and were associated with niche-/metaniche-specific cytokine profiles. Our findings allow the definition of distinct metaniches according to their microbial composition, partly reflected by their cytokine profile, and provide new insights into microenvironmental similarities between anatomical diverse oral niches.

Invasive fungal rhinosinusitis with palatal erosion in an elderly edentulous patient with uncontrolled diabetes: report of a rare case.

OBJECTIVES: To report a rare case of chronic invasive fungal rhinosinusitis with palatal erosion. BACKGROUND: Restoring and maintaining oral health of diabetic elderly patients with increased risk of infections is a challenge to the dentist. Patients suffering from uncontrolled diabetes are susceptible to fungal infections. Palatal erosion due to fungal rhinosinusitis is rare. MATERIALS AND METHODS: Case report of a 65 years old illiterate female patient from low socio-economic strata, suffering from uncontrolled diabetes and poor systemic health presenting with chronic invasive fungal rhinosinusitis leading to palatal erosion. CONCLUSION: Such a case is a diagnostic challenge to a dentist. Therefore understanding the disease process and its possible outcomes is desirable. The treatment warrants a multidisciplinary approach.

Streptococcus mutans counts in patients wearing removable retainers with silver nanoparticles vs those wearing conventional retainers: A randomized clinical trial.

INTRODUCTION: The rough surface of Hawley removable appliances provides an environment for plaque accumulation, leading to enamel demineralization. The aim of this study was to evaluate the effect of silver nanoparticles incorporated into acrylic baseplates of orthodontic retainers on Streptococcus mutans colony-forming units. METHODS: Sixty-six orthodontic patients at the debonding stage were randomly assigned to 2 sex-matched groups with stratified block randomization: group 1 received conventional removable retainers; group 2 received removable retainers containing silver nanoparticles (about 40 nm in size and 500 ppm in concentration). After comprehensive orthodontic treatment, patients who revealed no clinical evidence of dental caries, periodontal pockets, or systemic disease were considered eligible for this study. Swab samples were taken from the maxillary palatal side from the patient in the dental chair at retainer placement (T1, 1 week after debonding the fixed orthodontic appliance) and T2, 7 weeks later. The main outcome was to compare the number of S mutans colony-forming units between the 2 groups 7 weeks after retainer delivery. The results were analyzed by using analysis of covariance. The participants and the assessors were blinded to the allocation groups. RESULTS: Twenty-nine patients in the control group and 32 in the intervention group were analyzed. At T1, the intervention group had higher S mutans colony counts relative to the control group. The analysis of covariance test showed a significant reduction of colonies in the intervention group after 7 weeks. The mean difference of colony counts between the 2 groups was 40.31 (95% confidence interval, 24.83-55.79; P < 0.001). CONCLUSIONS: Adding silver nanoparticles to the acrylic plate of retainers had a strong antimicrobial effect against S mutans under clinical conditions. REGISTRATION: This study was registered as a clinical trial at the Iranian Clinical Trial Center under the code number IRCT201309239086N2. FUNDING: This trial was supported by Hamadan Dental Research Centre, Hamadan University of Medical Sciences, Hamadan, Iran.

A multispecies probiotic reduces oral Candida colonization in denture wearers.

PURPOSE: The prevalence of Candida infections has been rising with an increasingly aging population and a larger population of immunocompromised individuals. The use of probiotics may be an alternative approach to antifungal agents in the prevention and treatment of oral candidiasis. This study aimed to evaluate the short-term effect of probiotics in reducing the infection level of oral Candida in candidiasis-asymptomatic elderly denture wearers. MATERIALS AND METHODS: In a double-blind randomized study, 59 denture wearers harboring Candida spp. in the oral cavity with no clinical symptoms were allocated into two groups: probiotic and placebo. All patients were instructed to clean the denture daily. The probiotic group poured a capsule containing lyophilized Lactobacillus rhamnosus HS111, Lactobacillus acidophillus HS101, and Bifidobacterium bifidum daily on the palatal surface of the maxillary denture, whereas the placebo group was submitted to the same regimen using placebo capsules. Candida spp. infection levels were evaluated in palate mucosa samples obtained before and after a 5-week experimental period. RESULTS: All patients harbored Candida in the palate mucosa at baseline. Fifty-five individuals completed the experimental period. The detection rate of Candida spp. was 92.0% in the placebo group after the experimental period, whereas it was reduced to 16.7% in the probiotic group. The reduction promoted by the probiotic regimen was independent of baseline characteristics such as Candida infection level and colonizing species, age of denture, and other variables. CONCLUSION: The probiotic product was effective in reducing the colonization of the oral cavity with Candida in candidiasis-asymptomatic elderly denture wearers, suggesting that this multispecies probiotic could be used to prevent oral candidiasis. CLINICAL IMPLICATIONS: Colonization of oral surfaces by Candida is considered a risk factor for invasive fungal infections. The use of a product with L. rhamnosus, L. acidophilus, and B. bifidum may represent an alternative treatment for reduction of Candida infections in elderly denture wearers.

Crossover clinical trial of the influence of the use of adhesive on biofilm formation.

STATEMENT OF PROBLEM: Contrasting results have been reported regarding the influence of the use of adhesive on biofilm formation. PURPOSE: The purpose of this study was to evaluate the influence of the use of adhesive on the formation of biofilm on the internal surface of complete dentures and the palatal mucosa of denture wearers. MATERIAL AND METHODS: Thirty participants with well-fitting complete dentures were randomly divided according to the experimental design: protocol 1, adhesive use during the first 15 days, followed by no use of adhesive over the next 15 days; protocol 2, no use of adhesives during the first 15 days, followed by adhesive use over the next 15 days. After each period, material from the mucosa and intaglio of the maxillary dentures was collected. Replicate aliquots were plated onto Petri dishes containing selective media for Candida spp, Streptococcus mutans, and a nonselective culture medium. Colony-forming units were expressed as log (CFU+1)/mL. In addition, the internal surfaces of the maxillary and mandibular complete dentures were stained and photographed. From the photographs, the total internal surface and the surface stained with biofilm were quantified (software ImageTool 3.00), and the percentage of the biofilm-covered area (%) on the maxillary and mandibular dentures was calculated and compared with 2-way ANOVA. For the nonselective culture medium, data were compared with the paired-sample t test, and the Wilcoxon signed rank test was performed to compare the colony counts of Candida spp and Streptococcus mutans (α=.05). RESULTS: Similar colony counts were found with or without the use of adhesive for the mucosa and internal surfaces of maxillary dentures, irrespective of the culture medium (P>.05). The area of dentures covered with biofilm was influenced by the use of adhesive (P=.025), regardless of the type of denture (P=.121). CONCLUSIONS: The use of adhesive did not alter the colony counts of microorganisms from the palatal mucosa and maxillary dentures of complete denture wearers during the 15-day period, but it did influence the area covered with biofilm on the internal surfaces of the complete dentures.

Assessment of Candida species colonization and denture-related stomatitis in bar- and locator-retained overdentures.

The aim of this study was to assess the prevalence of denture-related stomatitis (DRS) in different attachment-retained overdenture wearers and its association with particular colonizing Candida species. Thirty-seven edentulous patients with implant-supported maxillary or mandibular overdentures were enrolled. A full clinical history was obtained, including details of patients' oral hygiene practices and the levels of erythema based on Newton's classification scale. Swabs were taken from the palate and investigated mycologically to identify the yeast colonies. Quantitative and qualitative microbiological assessments were performed, which included recording the total numbers of colonies (cfu), their color, and their morphological characteristics. Significant differences were found in cfu values between the attachment and inner surfaces of locator- and bar-retained overdentures (P < .05). Candida albicans was the most common species in both evaluations, being isolated from 81.3% of bar-retained overdentures and 38.1% of locator-retained overdentures. DRS developed in all patients using bar-retained overdentures but in only 71.4% of those using locator-retained overdentures. No statistically significant relationship was found between bar and locator attachments according to smoking habit, overnight removal, or plaque and gingival indices (P > .05).

Effects of local simvastatin-alendronate conjugate in preventing periodontitis bone loss.

BACKGROUND AND OBJECTIVE: Local host-modulation therapy is an emerging approach to prevent disease progression in sites with moderate periodontitis. The combination of simvastatin and alendronate would be an intriguing host-modulatory strategy because of the bone-anabolic properties of simvastatin and the antiresorptive/bone-targeting characteristics of alendronate. The objective of this study was to evaluate the effects of local administration of a simvastatin-alendronate-ß-cyclodextrin (SIM-ALN-CD) conjugate for preventing experimental periodontitis bone loss. MATERIAL AND METHODS: Twenty-four mature female Sprague-Dawley rats were treated with three, 12 µL injections, administered one week apart, bilaterally into the palatal/interproximal gingiva. The injections contained: (i) a conjugate of 0.5 mg of SIM and 3.75 mg of ALN-CD in H2 O; (ii) H2 O alone; or (iii) no treatment. One week later, the same sites were subjected to induction of experimental periodontitis by three injections (i.e. one injection administered every other day for five d) of 0.01 mg of Escherichia coli endotoxin [lipopolysaccharide (LPS)] in phosphate-buffered saline (PBS) or PBS alone. After an additional week, the rats were killed, the palates were harvested and interproximal bone volume and adjacent thickness were calculated using microcomputed tomography. Subsequently, specimens were decalcified, and interproximal histologic sections were stained with hematoxylin and eosin for evaluation of alveolar crest osteoclasts and surrounding inflammation. Values were compared among treatment groups using analysis of variance and the Kruskal-Wallis test. RESULTS: Interproximal bone volume was reduced by LPS injections (p ≤ 0.04), yet when experimental periodontitis was preceded by treatment with SIM-ALN-CD, more bone was preserved than after treatment with carrier alone (p = 0.007). While LPS caused a significant loss in bone thickness over the palatal roots (p ≤ 0.04), the injection protocol (PBS) also caused a significant loss of palatal bone thickness (p ≤ 0.03). However, prophylactic SIM-ALN-CD injections resulted in no further loss of bone thickness during experimental periodontitis. LPS injections gave histologic evidence of increased osteoclasts and subsulcular inflammation, both of which were reduced when preceded by treatment with SIM-ALN-CD (p ≤ 0.0002). CONCLUSION: The primary conclusion of this study was that locally applied SIM-ALN-CD has the potential to prevent episodes of periodontitis bone loss.

Development of a contemporary animal model of Candida albicans-associated denture stomatitis using a novel intraoral denture system.

Denture stomatitis (DS) is a fungal infection characterized by inflammation of the oral mucosa in direct contact with the denture and affects up to 50% of denture wearers. Despite the prevalence, very little is known about the role of fungal or host factors that contribute to pathogenesis. Recently, we developed a novel intraoral denture system for rodent research. This denture system consists of custom-fitted fixed and removable parts to allow repeated sampling and longitudinal studies. The purpose of this study was to use this denture system to develop a clinically relevant animal model of DS. To establish DS, rats were inoculated with pelleted Candida albicans, which resulted in sustained colonization of the denture and palate for 8 weeks postinoculation. Biofilm formation on the denture was observed by week 4 and on the palate by week 6 postinoculation. Rats were monitored for clinical signs of disease by assigning a clinical score after macroscopic examination of the palate tissue according to Newton's method. By week 4 postinoculation, the majority of inoculated rats with dentures exhibited a clinical score of 1 (pinpoint erythema). By week 6 and week 8 postinoculation, increasing percentages of rats exhibited a clinical score of 2 (diffuse erythema/edema). Histological analysis of palate tissue demonstrated progressively increasing inflammatory cell recruitment throughout the time course of the infection. Palatal biofilm formation was commensurate with development of palatal erythema, which suggests a role for biofilm in the inflammatory response.

Treatment with probiotics in experimental oral colonization by Candida albicans in murine model (DBA/2).

The aim of this study is to evaluate the oral colonization by Candida albicans in experimental murine immunosuppressed DBA/2 and treatment with probiotic bacteria. To achieve these objectives, 152 DBA/2-immunosuppressed mice were orally inoculated with a suspension of C. albicans containing 10(8) viable yeast cells, the animals were treated with nystatin or with the probiotics (Lactobacillus acidophilus and Lactobacillus rhamnosus). Evaluations were performed by Candida count from oral mucosa swabbing. The oral mucosa colonization by C. albicans started at day 1 after inoculation, remained maximal from day 3 until day 7, and then decreased significantly. Probiotics reduced the C. albicans colonization significantly on the oral mucosa in comparison with the untreated animal group. In the group treated with L. rhamnosus, the reduction in yeast colonization was significantly higher compared with that of the group receiving nystatin. Immunosuppressed animal model DBA/2 is a relevant model for experimental Candida oral colonization, and the treatment with probiotics in this model may be an effective alternative to prevent it.

Oral lesion in leprosy: borderline tuberculoid diagnosis based on detection of Mycobacterium leprae DNA by qPCR.

Oral lesions are rarely reported in paucibacillary forms of leprosy. We report here a case with an erythematous hyposensitive lesion in the palate and no skin lesions. In addition to routine tests, biopsies of the lesion in the palate and of clinically normal surrounding areas were performed and subjected to real-time PCR for detection of Mycobacterium leprae DNA. The biopsy of the oral lesion was positive for bacilli DNA, followed by positive serum anti-PGL-1 and Mitsuda test, but with negative histopathology. The patient was diagnosed with a borderline tuberculoid form. After multidrug therapy the lesion had significantly regressed and the bacilli DNA detection in the former lesion was negative. The bacilli DNA detection in an oral lesion by real-time PCR not only improved leprosy diagnosis, but also helped in the classification of clinical form, and in the establishment of the appropriate therapeutic regime.

Oral colonization by Candida species in AIDS pediatric patients.

The aim of this study was to assess the prevalence of factors associated with oral colonization by Candida spp. in pediatric patients with AIDS. The sample comprised of 117 children. Clinical status, medicines in use, and laboratory findings were obtained from hospital records; sociodemographic data were given by relatives. A dental examination assessed the prevalence of dental caries. The prevalence of oral colonization by Candida was 62%. Only seven children presented clinical manifestation of oral candidosis despite their high viral load index and low-for-age CD4 count. Candida colonization was directly associated with frequent use of antibiotics (prevalence ratio [PR] = 1.44), sulfa drugs (PR = 1.23), alteration in the oral mucosa (PR = 1.55), and untreated dental caries (PR = 1.93). It was inversely associated with the use of antiretroviral therapies (PR = 0.65). Candida albicans was the most frequently detected species (80%); phenotypic tests did not detect C. dubliniensis strains. This study observed a low prevalence of Candida-related oral lesions in these patients, which is compatible with the hypothesis that antiretroviral medicines may have contributed to reducing oral manifestations from Candida infection. The high prevalence of Candida colonization in HIV+/AIDS children with untreated dental caries reinforces the importance of oral health care in interdisciplinary health units that assist these patients.

Oral candidal colonization in cleft patients as a function of age, gender, surgery, type of cleft, and oral health.

PURPOSE: To assess the colonization rate of oral Candida species and the influence of age, gender, oral health status, number of surgeries, and type of cleft. PATIENTS AND METHODS: A prospective study of 60 patients with cleft and 60 control subjects was carried out at the Cleft Centre at King Abdullah University Hospital and the Maxillofacial Unit at Jordan University of Science and Technology between October 2007 and June 2008. Oral health was assessed using the Gingival, Plaque, and Decayed, Missing, and Filled (DMFT/dmft) indexes using World Health Organization criteria. A culture swab was obtained from the tongue and buccal and palatal mucosae. Candida albicans and other Candida species were identified using the germ tube test and the automated biochemical test panel VITEK. RESULTS: The colonization rate of Candida in patients with cleft (63.3%) was significantly higher than in healthy control subjects (18.3%). The colonization rate of Candida and the distribution of C albicans varied with age but were not significantly associated with gender in patients with cleft and healthy controls. The candidal colonization rate was highest in patients with cleft who had at least 3 surgeries (78.2%) and in patients with bilateral clefts (77.7%). Patients with cleft had a significantly poorer health status than healthy controls; however, this was not influenced by the type of the cleft or the number of surgeries. CONCLUSION: Patients with cleft had a significantly higher rate of oral candidal colonization compared with control subjects, which varied with age, type of cleft, and the number of surgical interventions. Oral health status was significantly poorer in patients with cleft.

Clinical and microbiological efficacy of three different treatment methods in the management of denture stomatitis.

OBJECTIVE: This study evaluated. the effect of mouthrinses and tissue conditioner on the clinical findings and microbial flora of 60 patients with Newton's type II denture stomatitis (N2DS) BACKGROUND: Denture stomatitis is a common problem in complete denture wearers. MATERIALS AND METHODS: Sixty patients with N2DS were included in this study and divided into three groups. Two groups of patients were instructed to rinse their mouth with the designated mouthrinses DioxiDent and Corsodyl twice daily for 1 min and to soak their dentures overnight in these solutions for 15 days. For the third group, tissue conditioner was placed in each of 20 patients' existing maxillary dentures. Patients were evaluated both clinically and microbiologically at baseline and after 15 days. Palatal swabs and smears were taken from each patient before and after treatment and these samples were examined mycologically. The difference between Candida colonisation before and after treatment and the differences between pre-treatment and post-treatment clinical findings were assessed. RESULTS: DioxiDent and Corsodyl showed an improvement in palatal inflammation and a decrease in Candida colonisation compared to Visco-gel. CONCLUSIONS: The effectiveness of topical chlorine dioxide and chlorhexidine gluconate in the management of N2DS was demonstrated.

Rhizomucor variabilis var. regularior and Hormographiella aspergillata infections in a leukemic bone marrow transplant recipient with refractory neutropenia.

Rhizomucor variabilis and Hormographiella aspergillata rarely cause human infections. This report details a fatal case of a 14-year-old female with leukemia posthematopoietic cell transplant and relapse with refractory pancytopenia. The patient first developed an R. variabilis var. regularior palate infection and later developed a cutaneous H. aspergillata infection while on posaconazole and caspofungin therapy.

The role of Candida albicans hyphae and Lactobacillus in denture-related stomatitis.

Denture-related stomatitis (DRS) is still a dilemma in removable prosthodontics. The aim of this study was to investigate the relationship of DRS with the presence of Candida albicans hyphae and Lactobacillus. A total of 91 patients wearing maxillary and mandibular complete dentures were included in the present study and tested mycologically as well as bacteriologically. A statistically significant association of DRS was found with denture age (p = 0.003) and continuous denture wearing (p = 0.015). Presence of C. albicans hyphae was shown to be significantly higher in DRS cases (p < 0.01), and there was a statistically significant positive correlation between presence of hyphae and C. albicans (p < 0.01). Another interesting finding was that DRS patients showed higher Lactobacillus counts in their saliva (p = 0.04), as well as in the palate (p = 0.028). C. albicans is an important factor in the development of DRS. Hyphae seem to facilitate the rise of C. albicans counts and be related to the inflammatory response of the tissues. Lactobacillus seems to play an important role in the presence of DRS, as well. In agreement with many other studies, the results of this study confirm the importance of denture age and continuous denture wearing in the development of DRS.

Colony morphologies, species, and biotypes of yeasts from thrush and denture stomatitis.

OBJECTIVE: To study the species and phenotypic characteristics of yeasts, i.e. colony morphology, biotypes, and biotype relatedness, and the oral distribution of yeasts, in thrush and denture stomatitis. MATERIAL AND METHODS: Yeast colony morphology was observed under a stereo-microscope and photographed with a digital camera. Genus, species, and biotypes of the yeast isolates were identified by using a commercial kit, ID 32C. Yeast biotype dendrograms were generated by Spotfire software and SPSS 15.0 for Windows. RESULTS: Multiple colony morphologies were observed among the yeasts from both thrush and denture stomatitis. One genus, 6 species, and 21 biotypes were identified among the yeasts from thrush, while 2 genera, 7 species, and 20 biotypes were identified among the yeasts from denture stomatitis. Considerable similarities in predominant species, biotypes, and biotype clustering profiles were shown among the yeasts from thrush and denture stomatitis. However, Candida dubliniensis was identified exclusively in subgingival areas and biotype 7347340215 of C. albicans was identified more frequently in palate and sulci in thrush. CONCLUSIONS: A diversity of species and phenotypes was found among the yeasts in thrush and denture stomatitis. Candidal commensals were predominant in thrush and denture stomatitis, but the observation of divergent Candida species and biotypes, constituting 23% of all the yeast isolates, should not be ignored.

Molecular community profiling of the bacterial microbiota associated with denture-related stomatitis.

Denture-associated stomatitis (DS) affects over two-thirds of denture-wearers. DS presents as erythema of the palatal mucosa in areas where denture-surface associated polymicrobial biofilms containing the fungus Candida albicans exist. The contribution of the oral bacterial microbiota toward the infection is unknown. Therefore, this study characterised the bacterial microbiota of sites within the oral cavity to identify potential associations with occurrence of DS. Denture-wearing patients were recruited (denture stomatitis (DS) n = 8; non-denture stomatitis (NoDS) n = 11) and the oral bacterial microbiota of the tongue, palate and denture-fitting surface was characterised using next-generation sequencing. Operational taxonomic units (OTUs) were identified to bacterial genera and species, and presence/absence and relative abundances were examined. A significant (P = 0.007) decrease in the number of OTUs and thus, diversity of the microbiota was observed in tongue samples of DS patients (vs non-DS). The microbiota of denture-fitting surfaces and palatal mucosae were similar. Large differences in the abundance of bacterial genera and species were observed at each sample site, and unique presence/absence of bacteria was noted. Presence/absence and relative abundance of specific bacteria associated with DS warrants further in vitro and in vivo evaluation, particularly as our previous work has shown C. albicans virulence factor modulation by oral bacteria.

The spectrum of intraoral bacteria seen in patients with cleft palates in an African setting.

Dehiscence or palatal fistula formation following palatoplasty is a complication that has grave consequences for the patient that include tissue loss, emotional distress to the parents and patient, and further medical costs. Palatal dehiscence or fistula formation is multifactorial following surgery-tension of wound closure, poor patient adherence to postoperative orders and wound infection are the most common causes for this. Oral colonization with pathogenic organisms could play a role in wound healing complications. Identification of intraoral bacteria among patients with cleft palates has thus far not been performed. To identify the spectrum of intraoral bacteria in cleft palate patients in an African setting; a retrospective, chart review was performed at Inkosi Albert Luthuli Central Hospital-a quaternary hospital in Durban, South Africa. All patients with unrepaired cleft palates who underwent palatoplasty in 2015 were included. Fifty-two patients were included. Preoperative throat/palatal swabs were taken prior to palatoplasty. The various bacteria cultured from the aforementioned swabs were cataloged. Various bacteria were cultured. In total, 23 patients (44.2%) had positive swab cultures. Eighteen cultures (34.6%) had gram-positive growth only, four cultures (7.7%) had gram-negative growth only, while one patient (1.9%) cultured both a gram-positive and a gram-negative organism. Streptococcus viridans was the most commonly cultured organism (19.2%) while beta-hemolytic streptococci were cultured from only 4 swabs (7.7%). Our study cataloged the commonly occurring bacteria found in unrepaired cleft palate patients in Africa. Further research into the clinical significance of each bacteria is advised.