Astaxanthin restores the enzymatic antioxidant profile in salivary gland of alloxan-induced diabetic rats

Objective

To evaluate the effect of astaxanthin on antioxidant parameters of salivary gland from diabetic rats. The hypothesis of the study was whether the supplementation of diabetic rats with astaxanthin might antagonize, or at least prevent, the defect in their antioxidative status.

Design

Wistar rats (n = 32) were divided in 4 groups: untreated control, treated control, untreated diabetic and treated diabetic rats. Astaxanthin (20 mg/kg body weight) was administered daily by gavage for 30 days. On day 23, diabetes was induced by injection of alloxan (60 mg/kg body weight). After 7 days of diabetes induction, the rats were killed and submandibular and parotid removed. Superoxide dismutase (SOD), catalase, glutathione peroxidase and reductase activities and the content of thiol groups were determined. Data were compared by ANOVA and the Tukey test (p < 0.05).

Results

Diabetes caused a reduction of SOD, and thiol content and increase of catalase and glutathione peroxidase activities of submandibular gland whilst in the parotid gland diabetes caused an increase of thiol content and no effect in the antioxidant system. The astaxanthin restores the enzymatic activities in the salivary gland, however does not prevent its oxidative damage.

Conclusion

The submandibular gland presented more susceptibility to oxidative alterations induced by diabetes. Astaxanthin presented a positive effect on the oxidative protection of the salivary gland from diabetic rats.     

The role of salivary factors in persistent oral carriage of Candida in humans

Background

Candida albicans is a commensal oral yeast in approximately one-third to one-half of the healthy population. To date, there are no studies investigating the multiple anti-candidal salivary constituents of healthy individuals with either nil or, consistent oral yeast carriage.

Objective

To compare the composition and anti-candidal activity in stimulated whole saliva of healthy ‘consistent’ oral Candida carriers with Candida-free individuals.

Methods

A sub-sample of 22 consistent, Candida-free individuals and 10 consistent Candida carriers were recruited from a 12 months screening study investigating oral Candida carriage in 97 healthy patients treated by fixed orthodontic appliances. Unstimulated and stimulated saliva samples were collected. The following salivary attributes were measured using standard methodology: the flow rate, pH, lysozyme, lactoferrin and IgA concentration and, the degree of inhibition of blastoconidial growth and blastospore germination.

Results

Saliva from the Candida-free individuals showed 20.2% higher inhibition of blastoconidial growth (p < 0.05) of a reference strain of Candida albicans. No significant differences between the other salivary attributes of the two groups were found.

Conclusion

The fact that saliva of Candida-free individuals significantly inhibited the blastoconidial growth more than Candida-carriers (p < 0.05) suggests that saliva may play a role in modulating oral candidal populations in health. Further studies, with a larger cohort are needed to confirm these findings and determine the factors that confer enhanced salivary anti-candidal activity.     

Evaluation of the relationship between passive smoking and salivary electrolytes, protein, secretory IgA, sialic acid and amylase in young children

Objective

To evaluate the relationship between passive smoking as determined by salivary cotinine levels and salivary electrolytes, protein, secretory IgA, sialic acid and amylase in children.

Design

Saliva was collected from 90 passive smoker (PS) subjects (the study group) and 90 healthy age-matched children (the control group). The study group was divided into three subgroups according the number of cigarettes smoked. Socio-economic status, dental and dietary habits were recorded by questionnaire. Stimulated salivary calcium (Ca), phosphate (P), sodium (Na), potassium (P), total protein, amylase activity, sialic acid level, secretory IgA concentration and cotinine level were analysed. All data were analysed using SPSS, version 13.0.

Results

Socio-economic status, dental and dietary habits were similar between the two groups. The salivary electrolytes concentrations did not reveal significant difference between the two groups (p > 0.05). The mean cotinine levels of PS children were 1.58 ± 4.3 ng/mL. The salivary concentrations of protein were similar between the two groups (p > 0.05). The salivary secretory IgA concentration was significantly lower in the PS group than controls. The sialic acid level and amylase activity in PS group were found significantly higher compared with the controls (p < 0.05). No difference was observed for all these parameters with sex (p > 0.05). When saliva samples were analysed for output, the sialic acid level and amylase activity increased significantly in PS subjects (p < 0.05). Further, the output of secretory IgA concentration was found significantly lower compared with the controls (p < 0.05).

Conclusion

In conclusion, we show that passive smoking was associated with a decrease in secretory IgA concentration, whereas with increase in amylase activity and sialic acid level of stimulated whole saliva in young children.     

Levels of salivary stress markers in patients with anxiety about halitosis

Objective

To investigate the relationship between salivary stress markers and mental stress states in patients complaining of oral malodour. The utility of the salivary stress markers in assessment of mental conditions of those patients was also investigated.

Design

The study population included 74 patients, aged 20-59 years, who complained of oral malodour and were referred to the Breath Odor Clinic at Tokushima University Hospital. Patients were classified into two groups, genuine halitosis (GH) and psychosomatic halitosis (PH), according to the results of organoleptic rating measurement. All patients were subjected to examination by the Cornell Medical Index (CMI) Health Questionnaire. Resting saliva was collected and levels of salivary IgA, cortisol and chromogranin A were determined by ELISA. Twenty-three volunteers not complaining of halitosis were included as the control group. Kruskal-Wallis test and Mann-Whitney's U-test were used for statistical analysis.

Results

A significant increase was observed in the concentrations of salivary cortisol in the PH group as compared with GH and control groups (p < 0.05). Concentrations of IgA and chromogranin A in saliva were not significantly different among the three groups. In addition, higher salivary cortisol concentrations were found in CMI scale III and IV (tendency towards neurosis) than in scale I and II (normal) (p < 0.05). Since salivary cortisol reflects a status of chronic stress condition, psychosomatic halitosis might be closely related to this state of chronic stress.

Conclusions

Determination of cortisol levels in saliva may provide useful information for evaluating the mental status of patients complaining of halitosis.     

Salivary levels of IL-1β, IL-6, IL-8, and TNF-α in patients with burning mouth syndrome

Objective

To compare salivary IL-1β, IL-6, IL-8, and TNF-α levels between patients with burning mouth syndrome (BMS) and controls.

Design

Forty female patients with BMS (mean age: 61.6 ± 10.1 years) and 20 female control subjects (mean age: 65.1 ± 9.0 years) were included in the study. Unstimulated (UWS) and stimulated whole saliva samples (SWS) were collected and their flow rates were determined. Salivary IL-1β, IL-6, IL-8, and TNF-α levels and total protein concentration were also determined. Salivary transferrin level was determined to investigate the level of blood contamination in saliva samples. Gingival index of the subjects was also examined. Student's t-test, Pearson's correlation analysis, and analysis of covariance were used.

Results

No significant differences were found in the salivary levels of IL-1β, IL-6, IL-8, and TNF-α in BMS patients compared with controls. Salivary flow rates and their total protein concentrations did not differ significantly between the groups. The levels of salivary cytokines and total protein concentration correlated significantly with the level of blood contamination in both UWS and SWS.

Conclusion

There were no differences in the salivary levels of IL-1β, IL-6, IL-8, and TNF-α in BMS patients compared with controls. Cytokine levels in whole saliva were affected mainly by the amount of blood contamination.     

Small molecular weight proteins/peptides present in the in vivo formed human acquired enamel pellicle

Objective

The aim of this study was to investigate the type and the nature of peptides present in the in vivo formed human acquired enamel pellicle.

Design

Pellicle material was collected from 10 volunteers and subjected to sample preparations consisting of centrifugal filtration using a 10 kDa molecular weight cut-off membrane and high-resolution gel filtration chromatography. The fractions containing peptides <10 kDa obtained by both methods were analyzed by LC-ESI-MS/MS.

Results

78 natural pellicle peptides with molecular weights ranging from 766.9 Da to 3981.4 Da were identified originating from 29 different proteins.

Conclusions

The number of peptides present in acquired enamel pellicle appears to be large and this is likely to enhance the functional spectrum of this protein film. The presence of small peptides in pellicle may be functionally important since structure/function studies of many salivary proteins have shown that specific domains within these native proteins retain or even exhibit enhanced biological activities. The data present the basis for determining the precise function of these pellicle peptides and for gaining insights into the role pellicle plays in the oral cavity.     

Increased calcium and decreased magnesium and citrate concentrations of submandibular/sublingual saliva in sialolithiasis

Objective

The purpose of the present study was to investigate the electrolyte alterations of submandibular/sublingual saliva in submandibular sialolithiasis patients compared with saliva from healthy controls.

Design

Submandibular/sublingual saliva was collected from 10 submandibular sialolithiasis patients and from 10 sex- and age-matched healthy controls. Ion chromatography was performed to determine the concentrations of inorganic cations (potassium, calcium, magnesium, and sodium), inorganic anions (chloride, phosphate, nitrate, and sulphate) and organic anions (thiocyanate, lactate, acetate, and citrate).

Results

The calcium concentration was significantly higher in sialolithiasis patients than in controls (P < 0.05). In contrast, the levels of magnesium and citrate in the saliva of sialolithiasis patients were significantly reduced compared to the values obtained in controls (P < 0.05). No significant differences were detected among other ions.

Conclusions

Our findings indicate that saliva electrolyte composition of sialolithiasis patients is substantially altered with respect to crystallisation mechanisms. Increased calcium ion as a crystallisation substance and decreased magnesium and citrate ions as crystallisation inhibitors may be involved in the etiopathology of calculi formation.     

Availability of saliva for the assessment of alterations in the autonomic nervous system caused by physical exercise training

Objective

The purpose of the study was to assess the alterations of the autonomic nervous system activities caused by physical exercise training under food restriction using a running wheel in mice based on an analysis of saliva.

Methods

Male ICR mice, weighing 39-50 g, at 32 weeks of age were divided into three groups; an exercise with food restriction (EXP), an exercise without food restriction (EXA) and a control (CTL). The EXP group was fed the same amount of diet as the CTL group (pair-feeding). The EXP and EXA groups used a “voluntary running wheel” for exercise. The pilocarpine stimulated whole saliva was collected from the oral cavity by micropipette over 15 min 4, 8 and 12 weeks after the beginning of the experiment. The salivary flow rate, protein concentration and amylase and kallikrein activities were determined, since amylase and kallikrein release have been shown to be evoked by β- and α-adrenergic receptor stimulation, respectively.

Results

There was no significant difference in the sera corticosterone levels among the three experimental groups. The flow rate of saliva per total salivary gland weight in the EXP was significantly lower than that in the CTL and the EXA groups. The total protein secretion and kallikrein activity decreased by 20-30% in the EXP mice between 4 and 12 weeks after the starting of experiments in comparison to the CTL mice, thus suggesting that signal transduction in the α-sympathetic nervous system was downregulated. There was no significant difference in the amylase activity between the EXP and the CTL groups.

Conclusion

Physical exercise under diet control induced alterations in saliva secretion, while exercise training alone did not affect the content of saliva. The results demonstrate the availability of saliva and suggest that the present experimental situation is a suitable experimental model for sports activity performed under diet control.     

Specific expression of salivary maxi-K channel variant is augmented in diabetic mice

Background and objective

A genetically diabetic mouse strain (db/db) exhibits severe obesity and a syndrome resembling human non-insulin-dependent diabetes mellitus. Our histological study of submandibular glands revealed that the size and area of the granular convoluted tubules was substantially decreased in db/db mice. We hypothesized that this structural difference reflected a specific alteration in salivary duct function.

Methods

The saliva evoked by pilocarpine was used for the measurement of ion concentrations, and submandibular glands were dissected out for the immunohistochemistry and real-time PCR study.

Results

The K⁺ concentration of the salivary secretion was higher in db/db than in control m+/m+ mice, while neither saliva volume nor the concentrations of Na⁺ or Cl⁻ differed between these strains. In db/db mice (vs. m+/m+ mice): quantitative PCR analysis revealed an increased mRNA expression of large-conductance Ca²⁺-activated K⁺ (maxi-K) channels, immunohistochemistry revealed an increase in the luminal surface expression of the maxi-K channel protein, and a particularly interesting finding was that there was a substantial increase in the salivary tissue-specific splice variant ParSlo.

Conclusion

These results suggest that in db/db mice, the K⁺ content of saliva may be elevated due to an expression of a maxi-K channel variant, which results from a modification of ductal structure. General significance: Our data may shed some light on the mechanism responsible for determining the dynamics of salivary K⁺ concentration increased in diabetic patients.     

Higher levels of salivary MUC5B and MUC7 in individuals with gastric diseases who harbor Helicobacter pylori

Objective

The aim of the present study was to assess the salivary levels of MUC5B and MUC7 in individuals with dyspeptic disease and Helicobacter pylori (H. pylori) in the stomach, compared to individuals without dyspeptic disease.

Methods

30 individuals with dyspeptic disease, who underwent endoscopy for upper gastrointestinal complaints at Hospital Pedro Ernesto-RJ, Brasil and tested positive for H. pylori, and 23 controls with no dyspeptic disease, with mean age 53.5 ± 4.4 years, were included in the study. Saliva samples and 3 antral biopsy were taken for PCR analysis and histologic examination. In addition, saliva samples were tested by ELISA with F2 monoclonal antibody and EU7A antibody against MUC7, to determine MUC5B and MUC7 levels, prior to endoscopic examination. The expression pattern of the proteins was quantified by comparison to a pooled saliva sample of 19 healthy volunteers.

Results

MUC5B and MUC7 salivary levels were higher in the individuals with dyspeptic disease than in controls (p < 0.0001). 33.3% (9/30) of the dyspeptic individuals and 0% of the controls had H. pylori in the oral cavity.

Conclusions

Individuals with gastric diseases, with H. pylori in the stomach, showed higher levels of salivary H. pylori receptors-MUC5B and MUC7-than individuals without gastric diseases. These results suggest that higher levels of specific salivary mucins could be useful as risk indicators for infection by H. pylori.     

A universal pre-analytic solution for concurrent stabilization of salivary proteins, RNA and DNA at ambient temperature

Objective

Saliva is a biofluid that can be obtained from individuals without supervision by health care providers. To maximize this clinical advantage, it is highly desirable to have a global salivary analyte stabilizer for proteins, RNA and DNA at ambient temperature.

Design

Whole saliva, saliva supernatant and saliva filtrate (5.0 μm) were treated with RPS at room temperature (RT) for up to 6 days and then subjected to SDS-PAGE. Immunoblotting of β-actin and cystatin C were used to evaluate protein stability. For salivary DNA/RNA, whole saliva was incubated with RPS at RT for up to 10 weeks. After extracting total DNA/RNA in samples at week 0, 2, 6 and 10, DNA stability was assayed by chromosome 18 DNA qPCR and RNA stability by β-actin mRNA RT-qPCR.

Results

β-actin completely degraded in all types of saliva samples after 6-day incubation at RT. However, 24.0%, 91.4% and 89.3% of β-actin remained intact with RPS for whole saliva, saliva supernatant and filtrate, respectively. Similarly, 70.3% of cystatin C in supernatant remained intact in the presence of RPS. For salivary DNA/RNA, the cycle threshold (Ct) values showed no significant change for chromosome 18 DNA and β-actin mRNA in RPS-incubated saliva during the 10-week time course while significant increase in Ct values were observed in controls without RPS for both β-actin mRNA and DNA.

Conclusions

RPS provided effective concurrent stabilization to salivary DNA/RNA in whole saliva for up to 10 weeks and proteins in saliva filtrate for 6 days at RT. We also achieved separation of saliva supernatant from cellular elements by a simple filtration step (bypassing the need for centrifugation).     

Efficacy of natural antimicrobials in toothpaste formulations against oral biofilms in vitro

Objectives

To evaluate the antimicrobial efficacies of two toothpaste formulations containing natural antimicrobials (herbal extracts and chitosan) against oral biofilms of different composition and maturational status.

Methods

Bacteria from a buffer suspension or fresh saliva were adhered for 2 h to a salivary conditioning film and subsequently grown for 16 h. Dual-species biofilms were prepared from Actinomyces naeslundii T14V-J1 and Streptococcus oralis J22, whilst multi-species biofilms were grown from freshly collected human saliva. Biofilms were exposed to 25 wt% toothpaste supernatants. A chlorhexidine-containing mouthrinse and a buffer were used as positive- and negative-controls, respectively. Antibacterial efficacy was concluded from acute killing, bacterial removal, prevention of bacterial re-deposition and continued killing during re-deposition.

Results

The herbal- and chitosan-based supernatants showed immediate killing of oral biofilm bacteria, comparable with chlorhexidine. Moreover, exposure of a biofilm to these supernatants or chlorhexidine, yielded ongoing killing of biofilm bacteria after exposure during re-deposition of bacteria to a matured 16 h biofilm, but not to a much thinner initial biofilm formed by 2 h adhesion only. This suggests that thicker, more matured biofilms can absorb and release oral antimicrobials.

Conclusions

Supernatants based on herbal- and chitosan-based toothpastes have comparable immediate and ongoing antibacterial efficacies as chlorhexidine. Natural antimicrobials and chlorhexidine absorb in oral biofilms which contributes to their substantive action.     

Influence of gender on the metabolism of alcohols in human saliva in vitro

Objective

The aim of this study was to investigate possible gender differences in salivary metabolism of two alcohols, ethanol and 2-propanol. Ethanol and its metabolite acetaldehyde may play important roles in tumour development, especially in the upper digestive tract. 2-Propanol is tested to elucidate our previous findings, where gender-specific differences in salivary acetone levels were seen after exposure to this alcohol.

Design

Saliva was collected from 25 females and 22 males for in vitro exposure to 2-propanol. In the experiments with ethanol, saliva samples were collected from 17 females and 18 males. The saliva was exposed in vitro to 2-propanol or ethanol. The metabolites acetone, derived from 2-propanol, and acetaldehyde, derived from ethanol, together with the maternal substance were analysed by headspace gas chromatography.

Results

No differences related to gender, age, medication or tobacco intake in the acetone concentration in the saliva samples were found. Gender, age or tobacco intake did not result in difference in the production of acetaldehyde in saliva. However, in the pre-exposure samples the men had a significantly higher concentration of acetaldehyde compared to the women (p = 0.04). Also, there was a tendency (p = 0.05) to higher concentrations of acetaldehyde in the samples (at 1 mM ethanol exposure) from subjects who take medications.

Conclusion

No gender difference in the metabolism of 2-propanol and ethanol in human saliva in vitro were found.     

Does the neuromotor abnormality type affect the salivary parameters in individuals with cerebral palsy?

J Oral Pathol Med (2010) 39 : 770–774 Background: Previous studies reported alterations in salivary flow rate and biochemical parameters of saliva in cerebral palsy (CP) individuals; however, none of these considered the type of neuromotor abnormality among CP individuals, thus it remains unclear whether the different anatomical and extended regions of the brain lesions responsible for the neurological damage in CP might include disruption of the regulatory mechanism of saliva secretion as part of the encephalopathy. The aim of this study was to evaluate salivary flow rate, pH and buffer capacity in saliva of individuals with CP, aged 3–16 years, with spastic neuromotor abnormality type and clinical patterns of involvement. Methods: Sixty‐seven individuals with CP spasticity movement disorder, were divided in two groups according to age (3–8‐ and 9–16‐years‐old) and compared with 35 sibling volunteers with no neurological damage, divided in two groups according to age (3–8‐ and 9–16‐years‐old). Whole saliva was collected under slight suction and pH and buffer capacity were determined using a digital pHmeter. Buffer capacity was measured by titration using 0.01N HCL, and flow rate was calculated in ml/min. Results: In both age groups studied, whole saliva flow rate, pH and buffer capacity were significantly lower in the spastic CP group (P < 0.05). The clinical patterns of involvement did not influence the studied parameters. Conclusion: These findings show that individuals with spastic cerebral palsy present lower salivary flow rate, pH and buffer capacity that can increase the risk of oral disease in this population.     

Relationships of beta-blockers and anxiolytics intake and salivary secretion, masticatory performance and taste perception

Objective

Assess the influence of salivary flow on physiological parameters of the stomatognathic system in patients who take beta-blockers or anxiolytic medications.

Design

Sixty patients were divided into three groups based on the following criteria: Group 1, control (n = 20; no use of medication); Group 2, use of antihypertensive beta-blockers (n = 20); and Group 3, use of benzodiazepine anxiolytics (n = 20). Salivary flow was assessed by determining stimulated and non-stimulated flow/minute. The quantification of the sense of taste was determined on a visual analogue scale (VAS) using solutions of 0.9% NaCl (salty), 50% sucrose (sweet), 20% unsweetened coffee (bitter) and 4.2% vinegar (sour). The DMFT index (number of decayed/missing/filled teeth) was determined by a calibrated examination, following the criteria of the World Health Organization (WHO). Masticatory performance was assessed with an Optosil comminution test and Rosim-Ramler equation.

Results

The results did not reveal a significant correlation between salivary flow and masticatory performance (p > 0.05). We observed significant decreased non-stimulated salivary flow for Group 2 (p = 0.05) when compared to controls. However, taste perception was not influenced by salivary secretion amongst groups. Furthermore, we observed a significant negative correlation between non-stimulated salivary flow and DMFT in Group 1 (p = 0.02; r = −0.52).

Conclusions

Patients under beta-blockers therapy presented reduced non-stimulated salivary flow when compared to controls, without influencing the sense of taste or masticatory performance. The use of anxiolytics did not affect salivary flow and taste perception in the studied sample.     

Polymorphic variants of genes related to arginine metabolism and the risk of orofacial clefts

Objective

Maternal mid-pregnancy low levels of symmetric dimethylarginine and newborn low levels of citrulline are suspected to be risk factors for orofacial clefts. This study was undertaken to investigate the involvement of polymorphic variants of genes related to arginine metabolism in the susceptibility of clefting.

Design

PCR-RFLP and HRM analyses were used to analyze single nucleotide polymorphisms (SNPs) of ASS1, ASL, and SLC25A13 in 172 children with non-syndromic cleft lip with or without cleft palate (CL/P) and 188 controls without congenital anomalies. The differences in allele and genotype frequencies between cases and controls were determined using standard Chi-square and Fisher exact tests. The odds ratio (OR) and associated 95% confidence intervals (95% CI) for individuals with CL/P versus controls were also calculated. Associations between the investigated polymorphisms and the risk of being born with an orofacial cleft were tested using the nonparametric and genetic model-free Multifactor Dimensionality Reduction (MDR) approach.

Results

Analysis of five SNPs of the ASS1 gene revealed that the G allele of rs7860909 is associated with increased CL/P risk. Compared to individuals with the AA genotype, the G allele carriers had an OR of 1.768 (95% CI: 1.133-2.759; p = 0.012). For the remaining SNPs of all analysed genes, there was no overall evidence for cleft association considering the allele and genotype distribution. However, gene-by-gene interaction analysis conducted using the MDR approach revealed a significant interactive genetic effect of ASS1 (rs666174) and SLC25A13 (rs10252573) on the occurrence of clefting (p = 0.002).

Conclusion

Our results demonstrate moderate evidence for the association of polymorphic variants of genes related to arginine metabolism with abnormal palatogenesis.     

Effect of a neutralising agent on the evaluation of the antimicrobial activity of chlorhexidine on the bacterial salivary flora

Objective

To test the efficacy of a previously described neutralising agent to counteract any antimicrobial activity of 0.2% of chlorhexidine (CHX) mouthrinse on the salivary flora, which is only exhibited after sampling of surviving bacteria, resulting in false positive efficacy data.

Methods

Unstimulated salivary samples were collected of 20 volunteers under basal conditions and at 30 s and 1 h after of a single mouthrinse of 0.2% CHX. Each salivary sample was divided into 2 equal aliquots; one was mixed with neutralising agent (3% Tween 80, 0.3% lecithin and 0.1% cysteine) and the other with a control solution. The colony forming units (cfu/mL) were determined and expressed as logarithms (log₁₀ cfu/mL).

Results

At baseline, the total bacterial concentrations were similar, independently of the addition of neutralising solution or control solution (8.419 ± 0.346 log₁₀ cfu/mL and 8.462 ± 0.474 log₁₀ cfu/mL, respectively, p = 0.440). At 30 s performing the CHX mouthrinse, the bacterial load reduction was statistically significant between both sampling methods (1.917 ± 1.275 log₁₀ cfu/mL, p < 0.001). One hour after performing the CHX mouthrinse, the bacterial load reduction was statistically significant between both sampling methods (0.537 ± 0.706 log₁₀ cfu/mL, p = 0.003).

Conclusions

Neutralising agent was not toxic to the bacterial salivary flora and effectively deactivated the “residual antimicrobial activity” of the 0.2% CHX (after exposure and during processing of samples). We propose the use of this neutralising agent when evaluating the antibacterial activity of CHX mouthrinses.     

Screening for subgingival occurrence of gram-negative enteric rods in periodontally diseased and healthy subjects

Objective

This study aimed to determine whether the variations in the occurrence of gram-negative enteric rods as detected through a longitudinal follow up with three consecutive visits, may be associated with the periodontal clinical status.

Design

Clinical and demographic parameters from 63 untreated chronic periodontitis (CP) subjects and 45 healthy controls (HC) were analyzed. Subgingival plaque samples were obtained from 6 sites in each subject at baseline, 1-week, and 1-month visits and processed using culture and biochemical tests. Culture findings were categorized taking into account the detection frequency of gram-negative enteric rods as persistent presence, transient presence, or absence of enteric rods in any sampling time.

Results

Although transient presence of gram-negative enteric rods was more prevalent in CP subjects (16.7%) than HC subjects (9.3%), the difference was not significant (P > 0.05). The majority of subjects showed a transient presence of gram-negative enteric rods at concentrations <2 × 10² CFU/mL. Persistent presence of gram-negative enteric rods was not observed in any subject through the entire study period. Moreover, differences in both the detection frequencies of individual species and the total number of gram-negative enteric rods were not statistically significant neither inter- nor intragroups.

Conclusion

The findings of the present study could indicate that gram-negative enteric rods are merely transient microorganisms within the subgingival environment and suggest that the periodontal clinical status appeared not to be influenced by the presence of these species.