Diversity of the oral microbiome between dentate and edentulous individuals.

BACKGROUND: Measurement of saliva microbes is promoted as a way to detect oral and systemic disease, yet there is a multitude of factors that affect the oral microbiome. The salivary microbiome is influenced by oral biofilm of shedding (epithelial) and non-shedding (tooth) surfaces. METHODS: To gauge the ability of salivary microbial analytics to distinguish between edentulous and dentate oral conditions, we looked for differences in the saliva microbiome of subjects with and without teeth. Fifty-two dentate and 49 edentulous subjects provided stimulated saliva samples. 16S rRNA gene sequencing, QIIME-based data processing, and statistical analysis were done using several different analytical approaches to detect differences in the salivary microbiome between the two groups. RESULTS: Bacteria diversity was lower in the edentulous group. Remarkably, all 31 of the most significant differences in taxa were deficits that occur in the edentulous group. As one might expect many of these taxa are attributed to dental plaque and gingival sulcus associated bacteria. CONCLUSION: In sum, the measurement of 16S rRNA genes in the bacteria of the saliva can be used to reproducibly measure differences in the oral microbiome that occur with edentulism, mainly the lack of tooth and tooth-related structures.

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.

Does the Prevalence of Periodontal Pathogens Change in Elderly Edentulous Patients after Complete Denture Treatment?

PURPOSE: To determine if wearing complete dentures can cause changes in prevalence of some of the most common periodontal pathogens in elderly edentulous patients. The need for understanding the composition of oral microflora in edentulous patients has been recognized by some authors, but no studies have dealt with the changes that occur in periodontal pathogens' prevalence as a result of complete dentures. MATERIALS AND METHODS: A total of 30 edentulous elderly (average age 71) patients participated in the study. Complete dentures were fabricated for each patient, and the residual alveolar ridges were swabbed before denture insertion. After a period of 6 months swabs were taken again. Identification of P. intermedia, A. actinomycetemcomitans, P. gingivalis, T. forsythia, T. denticola, and F. nucleatum was done by the polymerase chain reaction (PCR) method and primers specific for each microorganism. RESULTS: A noticeable increase in the presence of periodontal pathogens was observed after 6 months of denture wearing; targeted bacteria were identified in 17 pre-insertion samples compared to 28 post-insertion samples. The McNemar test was used to compare the prevalence of periodontal pathogenic bacteria before and after dental treatment. p<0.05 indicated statistical significance. Three microorganisms showed a statistically significant difference between the first and second swabbing-A. actinomycetemcomitans (6.7% vs. 40.0%, p = 0.006), P. intermedia (30.0% vs. 73.3%, p = 0.004), and T. forsythia (6.7% vs. 30.0%, p = 0.004). There was also an increase in bacteria co-associations 6 months post-insertion of complete dentures. CONCLUSIONS: The results of the present study suggested that wearing complete dentures caused a considerable increase of periodontopathic bacteria prevalence in elderly patients. Better understanding of oral microflora and the impact dental treatment has on bacterial colonies is important in modern dentistry.

Analysis of P. gingivalis, T. forsythia and S. aureus levels in edentulous mouths prior to and 6 months after placement of one-piece zirconia and titanium implants.

BACKGROUND: It has been suggested that completely edentulous patients harbour fewer periodontopathic bacteria compared with dentate patients, due to the removal of the subgingival periodontal environment. However, reappearance of certain microbes has been reported after the placement of implants in these patients. AIM: The aim of this study was to determine whether the periodontopathic bacteria Porphyromonas gingivalis and Tannerella forsythia, as well as the non-periodontopathic bacterium, Staphylococcus aureus, emerged in edentulous patients 6 months after placement of one-piece zirconia and titanium implants. MATERIALS AND METHODS: Twenty-six patients were included in the study (titanium = 13, zirconia = 13). Microbial samples were collected from the tongue prior to implant placement and 6 months after implant placement from both the tongue and from around the implants. A qRT-PCR assay using SYBR green/ROX chemistry was used for the detection and quantification of rgp, nuc and karilysin single-copy gene of P. gingivalis, T. forsythia and S. aureus, respectively. Positive controls used in the study were pure bacterial gDNA purified from cultures of P. gingivalis and S. aureus, a cloned sequence of the karilysin gene for T. forsythia, a plaque sample positive for P. gingivalis and T. forsythia, and nasal gDNA for S. aureus. RESULTS: The results show that prior to implant placement, all three bacterial species were below the lower limit of quantification in all edentulous patients. The samples collected from the tongue and around the implants remained below the lower limit of quantification for each of the three species. However, all positive controls used in the study were detectable in the samples. qPCR standard curves showed correlation coefficients >0.97 and efficiencies >94.5% (slope range -3.19 to -3.46) for each of the SYBR green PCR assays. CONCLUSION: The results of this study indicate that the tested organisms did not emerge 6 months after implant placement irrespective of the nature of the implant biomaterial. A further follow-up of at least 2 years post-implantation of these patients is suggested to determine whether there are any changes in the oral microbiota and whether such changes are associated with the development of peri-implant disease.

Changes in oral microflora after full-mouth tooth extraction: a prospective cohort study.

AIM: The aim of the study was to evaluate the effect of full-mouth tooth extraction on the oral microflora, with emphasis on the presence and load of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. MATERIAL AND METHODS: Adult patients (n = 30), with moderate to advanced periodontitis and scheduled for full-mouth tooth extraction, were consecutively selected. Prior to and 1 and 3 months after full-mouth tooth extraction saliva, tongue, buccal and gingival mucosa and subgingival plaque/prosthesis samples were obtained. Aerobic and anaerobic culture techniques and quantitative real-time polymerase chain reaction (qPCR) were employed for the detection of oral pathogens. RESULTS: Full-mouth tooth extraction resulted in reduction below detection level of A. actinomycetemcomitans and P. gingivalis in 15 of 16 and 8 of 16 previously positive patients using culture techniques and qPCR, respectively. Those patients remaining qPCR positive showed a significant reduction in load of these bacteria. CONCLUSION: Full-mouth tooth extraction significantly changes the oral microflora. These changes include reduction of A. actinomycetemcomitans and P. gingivalis, frequently to levels below detection threshold. In some patients, A. actinomycetemcomitans and P. gingivalis can persist in the edentulous oral cavity up to 3 months after full-mouth tooth extraction.

Oral microbial colonization in laryngectomized patients as a possible cofactor of biofilm formation on their voice prostheses.

AIM: Biofilm formation on voice prostheses, which are used for voice rehabilitation in laryngectomized patients, is a main cause of device failure. The aim of this study was to assess whether the presence of periodontal pathogens in the biofilm on voice prostheses is related to that in the oral cavity and associated with the periodontal status of the patients. METHODS: Thirty-one laryngectomized patients were invited to participate, 13 of whom met exclusion criteria. The remaining 18 were classified according to the community periodontal index of treatment needs (community periodontal index of treatment needs (CPITN), grades 0-4). Biofilm samples from the oral cavity and voice prostheses were analysed by PCR-based hybridization for 11 pathogens. RESULTS: All dentate patients required periodontal treatment (CPITN-3: n = 4, CPITN-4: n = 8); the remaining six were edentulous. The diversity (i.e. number of bacterial species detected) of pathogens detected on the voice prostheses correlated significantly positively with the diversity of pathogens in the oral cavity and with clinical parameters. Furthermore, the diversity of pathogens differed significantly between dentate and edentulous patients. CONCLUSIONS: Results emphasize the oral cavity as an important source of bacteria for biofilm formation on voice prostheses. Whether these pathogens reduce the lifetime of the device by increased biofilm formation and/or increase the risk of silicone deterioration requires further study.

Comparative analysis of colony counts of different species of oral streptococci in saliva of dentulous, edentulous and in those wearing partial and complete dentures.

OBJECTIVES: To study and compare the number of colony forming units of Streptococcus mutans, Streptococcus sanguis, Streptococcus salivarius, Streptococcus mitis and Streptococcus milleri in dentulous, edentulous and in those wearing partial and complete dentures by using semi-quantitative culture method of saliva samples with calibrated standard loop. MATERIALS: Sterile specimen collection bottles, Mitis salivarius agar plates, Standard loop, Candle jar, Incubator, Colony counter. METHODOLOGY: Study population consisted of 100 subjects with 25 in each group, with an age range of 40 to 80 years, who were attending the Department of Community Dentistry and Prosthodontics at MNR Dental College, Sangareddy, Hyderabad. Unstimulated saliva samples were collected from patients and inoculated on to Mitis salivarius agar plates using calibrated standard loop. The plates were then incubated anaerobically at 37°C for 24 hours and left at room temperature for further 24 hours. Using a colony counter, the number of colonies of each species was counted. RESULTS: Streptococcus mutans and Streptococcus mitis predominates in the dentulous group, Streptococcus sanguis in complete denture group, Streptococcus salivarius in edentulous group and Streptococcus milleri in removable partial denture group. CONCLUSION: The results of our study are in accordance with the previous studies, which have sought to differentiate different groups of mutans streptococci using a simple calibrated standard loop.

Impact of tooth loss on oral and systemic health.

Periodontitis is a primarily bacterial infection that is common in dentate individuals, while denture stomatitis is a predominantly fungal infection that is common among denture wearers. Both infections may increase a patient's risk for chronic systemic infection dissemination, and may in turn increase the risk of chronic, inflammatory-based systemic diseases. Systemic diseases for which chronic oral infections are believed to confer attributable risk include atherosclerotic and coronary disease, stroke, chronic obstructive pulmonary disease, diabetes, and hypertension. It appears that invasive oral pathogens trigger a systemic inflammatory response via mediators released by the cardiovascular system and liver, putting the patient at increased risk for these diseases. Data comparing gene expression between denture wearers with and without denture stomatitis (and associated Candida albicans infections) has demonstrated unique up- and down-regulation patterns for a number of genes. It appears that down-regulated genes (whose functions are thereby diminished) are associated with reduced epithelial barrier integrity. By contrast, there appears to be an association between up-regulated genes (which have enhanced function) and inflammatory responses that facilitate the ability of C. albicans to bind with and penetrate the oral mucosa. Molecular biological approaches suggest that future therapeutic development could target reducing either the local inflammatory processor, the binding and attachment of C. albicans to the oral mucosa, or both. Ongoing investigations are attempting to incorporate interventions into matrices, to provide a local and sustained presence to therapeutic interventions.

Microbial changes after full-mouth tooth extraction, followed by 2-stage implant placement.

BACKGROUND: Recent studies showed that qPCR could detect bacteria related to periodontitis and peri-implantitis in a low concentration after full-mouth tooth extraction. This study monitored the microbiota from tooth extraction, over 9 months of full edentulism, up to 1 year after abutment connection. MATERIAL AND METHODS: Ten patients with severe periodontitis were recruited. Six months after tooth extraction, implants were inserted. Three to 6 months later, they were connected to abutments. Plaque samples were collected from the tongue dorsum, saliva, and subgingival area (teeth/implants) before extraction up to 1 year after abutment connection, and analysed via culture, qPCR, and checkerboard technology. RESULTS: A reduction in the total amount of aerobic and anaerobic CFU/ml was observed. The concentration of Porphyromonas gingivalis and Tannerella forsythia (qPCR and checkerboard) in the saliva and, to a lower extent, on the tongue dorsum reduced. For Prevotella intermedia, changes were negligible and no changes could be detected for Aggregatibacter actinomycetemcomitans. The pristine subgingival niches were quickly colonized by key pathogens. Their final concentration remained low, while the detection frequencies remained very high over time. CONCLUSION: Complete edentulation results in a significant reduction of bacteria related to periodontitis and peri-implantitis, with the exception of A. actinomycetemcomitans, which might indicate that key pathogens can survive without pockets.

Determinants of serum IgG responses to periodontal bacteria in a nationally representative sample of US adults.

AIM: To assess the distribution of elevated antibody titres to multiple periodontal bacteria, including established/putative pathogens and health-related species, by selected demographic, behavioural, and oral- and general health-related characteristics. METHODS: Data from 8153 >or=40-year-old participants from the third National Health and Nutrition Examination Survey were used, including 1588 edentulous individuals. We used checkerboard immunoblotting to assess serum IgG levels to 19 periodontal species. Thresholds for elevated antibody responses were defined for each species using the 90th percentile titre in periodontal healthy participants, using two alternative definitions of periodontitis. RESULTS: Edentulous individuals showed lower antibody responses than dentate participants, notably for titres to "red complex" species and Actinobacillus actinomycetemcomitans. Elevated titres to Porphyromonas gingivalis were twice as prevalent in participants with periodontitis than in periodontal healthy individuals. Non-Hispanic blacks and Mexican-Americans were more likely to display elevated titres for P. gingivalis compared with non-Hispanic whites (22.9%versus 19.4%versus 9.5%). Current smokers were significantly less likely to exhibit high titres to multiple bacteria than never smokers. CONCLUSION: Demographic, behavioural, and oral- and general health-related characteristics were strong determinants of systemic antibody responses to periodontal bacteria in a nationally representative sample of US adults.

Do elderly edentulous patients with a history of periodontitis harbor periodontal pathogens?

OBJECTIVES: The presence of periodontal pathogens in the oral cavity may impact implant survival. Therefore, this study aimed to determine the prevalence of Campylobacter rectus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Tannerella forsythia, Treponema denticola, Eikenella corrodens and Parvimonas micra in a specific elderly population with a history of periodontitis who have never worn dentures. MATERIAL AND METHODS: Thirty dentate subjects (mean age 61.7+/-7.05 years) and 30 edentulous subjects (mean age 65.8+/-8.05 years) were included in this cross-sectional study. Microbiological samples of cheek mucosa and the dorsum of the tongue were taken from all subjects. In addition, sulcus samples were taken from the dentate group. All samples were analysed using a bacterial DNA-specific polymerase chain reaction. RESULTS: All the pathogens studied were detected in dentate and edentulous subjects. When cheek and tongue samples were combined, C. rectus, A. actinomycetemcomitans and E. corrodens presented with a similar prevalence in both groups, whereas the other species were more prevalent specifically in the dentate group (P<0.05). In dentate subjects, P. intermedia and T. denticola were present in higher frequencies in the cheek mucosa (26.67% and 66.67%, respectively), whereas P. gingivalis and T. forsythia were more prevalent in the tongue samples (26.67% and 56.67%, respectively). CONCLUSIONS: Periodontal pathogens may persist in the oral cavity of edentulous subjects who have had periodontal disease, even 1 year after the extraction of all teeth and in the absence of other hard surfaces in the mouth.

Characterization of the normal bacterial flora in peri-implant sulci of partially and completely edentulous patients.

PURPOSE: To characterize the normal bacterial flora and evaluate the presence of periodontopathogenic bacteria around dental implants and to correlate them with the periodontal flora or, in completely edentulous patients, the alveolar gingival flora. MATERIALS AND METHODS: Clinical and radiographic parameters were recorded to exclude peri-implantitis in 34 partially edentulous and 19 completely edentulous patients. Partially edentulous patients were subdivided into two subgroups based on the depth of the periodontal pocket: ≤ 4 mm (n = 19) and > 4 mm (n = 15). Microbial samples were collected from peri-implant sulci, the deepest periodontal sulci, and, for completely edentulous patients, from the alveolar gingiva. Predominant aerobic bacteria were determined by microbiologic culturing, and multiplex polymerase chain reaction was used to detect five periodontopathogenic bacteria: Porphyromonas gingivalis, Tannerella forsythensis, Treponema denticola, Prevotella intermedia, and Actinobacillus actinomycetemcomitans. RESULTS: In all the examined patients, oral streptococci were the most frequent aerobic peri-implant bacteria. The frequency of four periodontopathogenic bacteria in tooth sulci (A actino?mycetemcomitans, P gingivalis, T forsythensis, T denticola) was significantly higher around natural teeth with deeper periodontal pockets, but there was no significant difference in the frequency of the same bacteria in peri-implant sulci in the two partially edentulous subgroups. In contrast, there were no such bacteria in the peri-implant sulci or the alveolar gingiva of completely edentulous patients. CONCLUSIONS: In healthy peri-implant sulci, oral streptococci constitute the predominant bacterial flora. In partially edentulous patients four periodontopathogenic bacteria were detected around implants, and none of these bacteria were found around implants in completely edentulous patients.

Oral environmental factors affecting number of microbes in saliva of complete denture wearers.

The purpose of this study was to clarify which oral environmental factors affected number of microbes in saliva in an edentulous environment. We enrolled 68 edentulous subjects in the study. Numbers of total anaerobic bacteria and Candida species in saliva were determined. Age, sex, un-stimulated salivary flow rate, pH and viscosity of saliva, histatin level in saliva, tongue coating status, tongue pressure, denture plaque status, material of denture base, duration of edentulism, frequency of self oral health care and number of cigarettes per day were also investigated as oral environmental factors. Correlation between number of total anaerobic bacteria or Candida species and each oral environmental factor was determined with the Spearman rank correlation coefficient. Stepwise logistic regression analysis was used to identify which factors were significantly associated with level of total anaerobic bacteria and Candida species. Correlation and stepwise logistic regression analyses revealed associations between un-stimulated salivary flow rate, tongue coating status, denture plaque status or frequency of self oral health care and number of total anaerobic bacteria. The correlation analysis showed a significant correlation between age and number of total anaerobic bacteria. Stepwise logistic analysis revealed associations between pH of saliva or viscosity of saliva and level of anaerobic bacteria; it also revealed associations between histatin level in saliva or un-stimulated salivary flow rate and level of Candida species. We conclude that salivary flow rate, in particular, affects number of salivary microbes in an edentulous environment.

Hyposalivation, oral health, and Candida colonization in independent dentate elders.

Hyposalivation is an important problem in elders and could interfere with several oral functions and microbial ecology. While the number of independent elders who retain more natural teeth increases worldwide, few studies examined hyposalivation in this population. Thus, this study aims to examine relationships between hyposalivation, oral health conditions and oral Candida colonization in independent dentate elders and evaluate factors associated with salivary flow and Candida carriage. We conducted a cross-sectional study in fifty-three dentate elders (≥65 years old with at least 4 pairs of posterior occlusal contacts) with no, or well-controlled, systemic conditions. Participants were interviewed for medical history, subjective dry mouth symptoms, oral hygiene practices and denture information. Unstimulated and stimulated salivary flow rates, objective dry mouth signs, gingival, tongue-coating, and root-caries indices were recorded. Stimulated saliva was cultured on Sabouraud-dextrose agar for Candida counts. Candida species were identified using chromogenic Candida agar and polymerase chain reaction. Statistical significance level was set at p<0.05. The results showed that hyposalivation was associated with higher gingival and tongue-coating indices (p = 0.003 and 0.015, respectively), but not root-caries index. Hyposalivation was also associated with higher prevalence of oral Candida colonization (p = 0.010; adjusted OR = 4.36, 95% confidence interval = 1.29-14.72). These two indices and Candida load were negatively correlated with unstimulated and stimulated salivary flow rates. Interestingly, non-albicans Candida species were more prevalent in denture wearers (p = 0.017). Hence, hyposalivation is a risk factor for poorer oral health and oral Candida colonization in independent dentate elders. Because of its potential adverse effects on oral and systemic health, hyposalivation should be carefully monitored in elders.

Do periodontopathogens disappear after full-mouth tooth extraction?

AIM: To monitor the intra-oral microbiological changes after full-mouth extraction using quantitative polymerase chain reaction (qPCR). MATERIAL AND METHODS: Nine patients with severe, aggressive periodontitis, for whom a full-mouth tooth extraction was the only remaining treatment option were recruited. Before and 6 months after extraction, microbial samples were obtained (tongue, saliva and subgingival plaque) and analysed by qPCR. RESULTS: The elimination of subgingival niches, by extraction of all natural teeth, resulted in a 3-log reduction of Porphyromonas gingivalis and Tannerella forsythia, and more modest reductions of Aggregatibacter actinomycetemcomitans and Prevotella intermedia. However, the detection frequencies of these periodontopathogens in saliva and on the tongue remained unchanged after full-mouth tooth extraction. CONCLUSION: In contrast to what has been believed so far, full-mouth tooth extraction does not result in eradication of all periodontopathogens but only in a significant reduction. The clinical consequences of this observation remain speculative.

Detection of periodontal pathogens in oral mucous membranes of edentulous individuals.

BACKGROUND: The purpose of this study was to investigate the colonization of Campylobacter rectus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Prevotella intermedia, and Tannerella forsythia (previously T. forsythensis) in the tongue and cheek of newborns and elderly individuals with no teeth. METHODS: Seventy-four edentulous subjects were included in this cross-sectional study. Microbiologic samples were taken from the dorsum of the tongue and cheek mucosa of all individuals and analyzed using a bacterial DNA-specific polymerase chain reaction. RESULTS: C. rectus was the most prevalent species in both groups (20.9% in the cheek of newborns, and 77.4% in the tongue of elderly subjects). P. gingivalis and P. intermedia were not detected in any of the 43 newborns; however, P. gingivalis was recovered from the tongue and cheek (3.2%) of elderly individuals, whereas P. intermedia was detected in the tongue (9.6%) and cheek (3.2%) of elderly individuals. T. forsythia was detected in newborns as well as elderly individuals, although the highest prevalence was observed in the tongue of newborns (6.9%) and elderly (9.6%) individuals. A. actinomycetemcomitans was not found in the tongue of newborns, but we observed A. actinomycetemcomitans in the cheek (2.3%) of newborns and in the tongue (12.9%) and cheek (6.4%) of elderly patients. CONCLUSIONS: Although we did not detect P. gingivalis and P. intermedia in newborns, periodontal pathogens could be detected from the oral mucous membranes of edentulous individuals. Our results suggest that major attention should be paid to edentulous individuals as an important measure in the prevention of the initial colonization of natural teeth and dental implants by periodontal pathogens.

Tongue-coating as risk indicator for aspiration pneumonia in edentate elderly.

Silent aspiration of oral microorganisms is a major cause of aspiration pneumonia. To establish oral hygiene criteria for the prevention of aspiration pneumonia in edentulous elderly persons, we investigated the relationship between presence of tongue-coating and number of oral bacteria in saliva and episodes of pneumonia. A total of 71 edentulous Japanese people aged 65 years or older living in nursing homes were enrolled in the study. A tongue plaque index (TPI) was used to evaluate quantity of tongue-coating, with TPI0 signifying no tongue-coating and TPI1 signifying presence of tongue-coating. Edentate elderly with TPI1 demonstrated significantly higher salivary bacterial counts than those with TPI0 (p<0.05). The number of elderly patients developing aspiration pneumonia was larger (p<0.005) in patients with TPI-based poor scores (average TPI>0.5) than in those with TPI-based good scores. The relative risk of developing pneumonia in the good tongue hygiene group compared with in the poor tongue hygiene group was 0.12, 95% confidence interval (CI): 0.02-0.9. The results demonstrate that tongue-coating is associated with number of viable salivary bacterial cells and development of aspiration pneumonia, suggesting that tongue-coating is a risk indicator of aspiration pneumonia in edentate subjects.

Biofilms in the edentulous oral cavity.

PURPOSE: The oral cavity presents numerous surfaces for microbial colonization. These surfaces produce biofilms of differing complexities unique to each individual. Several studies have looked at biofilms in dentate patients. There has been limited research regarding biofilms on dentures or soft tissues of edentulous patients. The purpose of the present investigation was to provide meaningful data describing microbial ecological relationships in the oral cavity of edentulous patients and to evaluate the microbiota on hard and soft tissue surfaces and saliva in edentulous patients wearing complete dentures. MATERIALS AND METHODS: Sixty-one edentulous subjects with complete maxillary and mandibular dentures were recruited. "Supragingival" biofilm samples were taken from 28 denture teeth for each subject. Biofilm samples were also taken from the dorsal, lateral, and ventral surfaces of the tongue, floor of mouth, buccal mucosa, hard palate, vestibule/lip, "attached gingiva," and saliva. Samples were individually analyzed for their content of 41 bacterial species using checkerboard DNA-DNA hybridization. Levels and proportions of each species were determined for every sample location. RESULTS: Periodontal pathogens such as Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were clearly present in the samples from the edentulous subjects. Microbial profiles in samples from the soft tissue surfaces differed among site locations. Samples from the dorsum of the tongue exhibited the highest bacterial counts followed by the "attached gingiva" and the lateral surfaces of the tongue, while the lowest mean counts were found in samples from the buccal mucosa and labial vestibules. Using cluster analysis of the proportions of the test species, three clusters were formed. The first cluster comprised saliva, supragingival plaque, and the lateral and dorsal surfaces of the tongue. The second cluster comprised the other six soft tissue surfaces. Species on the denture palate formed a third cluster. CONCLUSIONS: One of the major findings in this study was the detection of periodontal pathogens, A. actinomycetemcomitans and P. gingivalis, in the edentulous subjects, as these species were thought to disappear after removal of all natural teeth. This finding has implications regarding future dental treatment and the general health of individuals. Distinct patterns of microbial colonization were seen on the different soft tissue surfaces. Thus, this investigation provided the first step in defining the organisms that are associated with edentulous patients on both soft (mucosa) and hard surfaces (denture). The study also provided meaningful data that described microbial ecological relationships in the oral cavity of edentulous subjects. The authors believe that this study is the first comprehensive assessment of the microbiota in the complete denture-wearing subject.

Subgingival microbiota in peri-implant mucosa lesions and adjacent teeth in partially edentulous patients.

BACKGROUND: Osseointegrated dental implants have been shown to be a predictable approach to provide the adequate support for the replacement of missing teeth. It has been observed that implants showing signs of peri-implantitis contain subgingival microbiota similar to that around natural teeth with periodontal disease. This study identified the subgingival microbiota around implants with peri-implant lesions and natural teeth in partially edentulous patients. METHODS: Clinical and radiographic parameters were recorded and microbial samples taken from 16 implants with signs of pocketing, 12 neighboring and 11 non-neighboring teeth to the affected implants in 11 patients and 15 stable implants in eight patients (controls). Samples were cultured using techniques for Enterobacteriaceae spp and facultative/anaerobic periodontal pathogens. Statistical analysis included Friedman test to establish differences between the subgingival microbiota cultured from implants and teeth and two-tailed Mann Whitney test and chi square to find differences in two separate samples (P < or = 0.05). RESULTS: There were statistical differences between the subgingival microbiota in peri-implant lesions and stable implants for Gram-negative enteric rods (P <0.05). P. gingivalis (1.42%) was detected in peri-implant lesions but not in stable implants. A significant correlation between the subgingival microbiota from implants and neighboring teeth for Gram-negative enteric rods (P = 0.023) and implants and non-neighboring teeth for P. gingivalis (P = 0.042) was found. The frequency detection of Gram-negative enteric rods (75%) and P. intermedia/nigrescens (25%) was higher in peri-implant lesions (P <0.05). CONCLUSIONS: The subgingival microbiota in peri-implant lesions showed high levels of periodontopathic bacteria and superinfecting bacteria compared to healthy stable implants. The role of superinfecting bacteria in the pathogenesis of peri-implant lesions needs further investigation.

Mutans streptococci in xerostomic cancer patients after pilocarpine therapy: a pilot study.

OBJECTIVES: Opiod- and/or radiation-induced xerostomia in cancer patients is frequently associated with elevated levels of cariogenic mutans streptococci (MS). STUDY DESIGN: In a single-center, single blind 8-week clinical trial at The University of Texas M. D. Anderson Cancer Center, and from an initial sample of 32 patients, we evaluated MS counts in 28 cancer patients receiving chronic analgesic treatment for cancer pain. All patients received escalating doses of pilocarpine (Salagen) tablets, either 2.5 mg to 5 mg or 5 mg to 7.5 mg qid for 6 weeks, followed by placebo qid for a 2-week washout period. Whole resting saliva flow rates (g/5 min) and MS counts were evaluated at pretreatment, 3 weeks, 6 weeks, and 8 weeks. MS samples were obtained by 5-mL saline rinse (15 sec) at each visit prior to sialometry. RESULTS: In 19 patients (59%), MS counts exceeded 10(5) CFU/mL. At the end of the 6-week trial, 96% of patients showed a positive response to pilocarpine following a 30-minute postdosing evaluation (P=.001). MS counts were lower in 17 patients, higher in 6 patients, and nondetectable before and after pilocarpine in 5 patients (P=.03). CONCLUSION: The reduced MS counts associated with improved saliva flow rates following pilocarpine therapy in this short-term pilot study are encouraging, but further investigation in a larger group of patients over a longer study period is indicated.