Saliva on the oral mucosa and whole saliva in women diagnosed with burning mouth syndrome.

OBJECTIVE: The aim of the study was to examine mucosal saliva and unstimulated (UWS) and stimulated (SWS) whole saliva secretion rates and associated factors, in 56 female patients diagnosed with BMS and age-matched control women. MATERIAL AND METHODS: Mucosal saliva was assessed using the Periotron® method and blood flow using laser Doppler flowmetry. Diseases, drug usage and xerostomia were registered using questionnaires. RESULTS: The patients with BMS displayed less lingual and whole saliva, and more hyposalivation, xerostomia diseases/disorders and drug usage, compared to the controls. Only a low SWS and xerostomia differed after adjusting for drugs and systemic diseases. Regression analyses suggested an importance of saliva affecting drugs for saliva on the tongue and for SWS, and the total number of drugs used for UWS. Lingual saliva and UWS were also associated with systemic diseases in the patients. Xerostomia was significantly associated with drug use and whole saliva for all subjects but not in separate analyses of the groups. CONCLUSION: Less saliva in patients with BMS could be related to more systemic diseases and medication and not to the syndrome per se. Xerostomia in the patients was not related to any of these factors.

Clinical characterization of women with burning mouth syndrome in a case-control study.

OBJECTIVE: Burning mouth syndrome (BMS) is a chronic orofacial pain disorder that is defined by a burning sensation in the oral mucosa. The aim of this study was to investigate the underlying factors, clinical characteristics and self-reported oral and general health factors associated with BMS. MATERIAL AND METHODS: Fifty-six women with BMS (mean age: 67.7) and their age-matched controls were included in the study. A general questionnaire, an OHRQL index and BMS-specific questionnaires were used. Each subject underwent an oral examination. RESULTS: The mean severity of the BMS symptoms (VAS, 0-100) was 66.2 (SD 19.7). Overall, 45% of the patients reported taste disturbances. More of the patients than the controls rated their general health, oral health and life situation as 'less satisfactory'. The patients also reported more frequently on-going medications, diseases/disorders, xerostomia, allergy and skin diseases. Except for more bruxofacets among the patients, there were no significant differences regarding signs of parafunction. In a multiple logistic regression analysis, xerostomia and skin diseases showed the strongest prediction for BMS and no significant effect was found for medication, allergy or bruxofacets. CONCLUSIONS: Skin diseases and xerostomia but not parafunction were strongly associated with BMS. Our findings provide the basis for additional studies to elucidate the causal factors of BMS.

Rapid urease test (RUT) for evaluation of urease activity in oral bacteria in vitro and in supragingival dental plaque ex vivo.

BACKGROUND: Urease is an enzyme produced by plaque bacteria hydrolysing urea from saliva and gingival exudate into ammonia in order to regulate the pH in the dental biofilm. The aim of this study was to assess the urease activity among oral bacterial species by using the rapid urease test (RUT) in a micro-plate format and to examine whether this test could be used for measuring the urease activity in site-specific supragingival dental plaque samples ex vivo. METHODS: The RUT test is based on 2% urea in peptone broth solution and with phenol red at pH 6.0. Oral bacterial species were tested for their urease activity using 100 µl of RUT test solution in the well of a micro-plate to which a 1 µl amount of cells collected after growth on blood agar plates or in broth, were added. The color change was determined after 15, 30 min, and 1 and 2 h. The reaction was graded in a 4-graded scale (none, weak, medium, strong). Ex vivo evaluation of dental plaque urease activity was tested in supragingival 1 µl plaque samples collected from 4 interproximal sites of front teeth and molars in 18 adult volunteers. The color reaction was read after 1 h in room temperature and scored as in the in vitro test. RESULTS: The strongest activity was registered for Staphylococcus epidermidis, Helicobacter pylori, Campylobacter ureolyticus and some strains of Haemophilus parainfluenzae, while known ureolytic species such as Streptococcus salivarius and Actinomyces naeslundii showed a weaker, variable and strain-dependent activity. Temperature had minor influence on the RUT reaction. The interproximal supragingival dental plaque between the lower central incisors (site 31/41) showed significantly higher scores compared to between the upper central incisors (site 11/21), between the upper left first molar and second premolar (site 26/25) and between the lower right second premolar and molar (site 45/46). CONCLUSION: The rapid urease test (RUT) in a micro-plate format can be used as a simple and rapid method to test urease activity in bacterial strains in vitro and as a chair-side method for testing urease activity in site-specific supragingival plaque samples ex vivo.

Plaque pH in caries-free and caries-active young individuals before and after frequent rinses with sucrose and urea solution.

OBJECTIVE: To examine pH in the approximal dental biofilm after acid and alkali formation from sucrose and urea, after an adaptation period to these substances, in caries-free (CF) and caries-active (CA) individuals. Saliva flow and buffer capacity, and aciduric bacteria in saliva and plaque were also examined. MATERIAL AND METHODS: Twenty adolescents and young adults (15-21 years) with no caries (n = 10, D(m + i)MFS = 0) or ≥1 new manifest lesions/year (n = 10, DmMFS = 3.4 ± 1.8) participated. After plaque sampling, interproximal plaque pH was measured using the strip method before (baseline) and up to 30 min (final pH) after random distribution of a 1-min rinse with 10 ml of 10% sucrose or 0.25% urea. This procedure was repeated after a 1-week adaptation period of rinsing 5 times/day with 10 ml of the selected solution. After a 2-week washout period the second solution was similarly tested. Mutans streptococci, lactobacilli and pH 5.2-tolerant bacteria were analyzed by culturing. RESULTS: In the CF group, acid adaptation resulted in lowering of baseline and final plaque pH values after a sugar challenge, and in increased numbers of bacteria growing at pH 5.2, which was increased also after alkali adaptation. In the CA group, the final pH was decreased after acid adaptation. No clear effects of alkali adaptation were seen in this group. CONCLUSION: One-week daily rinses with sucrose and urea had the most pronounced effect on the CF group, resulting in increased plaque acidogenicity from the sugar rinses and increased number of acid-tolerant plaque bacteria from both rinses.

Protein and bacteria binding to exposed root surfaces and the adjacent enamel surfaces in vivo.

Exposure of root surfaces due to inflammatory tissue breakdown is a clinical characteristic of periodontitis. The gingival margin may further recede during treatment. Pellicles and early dental plaque on enamel surfaces of periodontitis patients have previously been described. The binding properties of exposed root surfaces, which may affect the incorporation of proteins from especially the GCF into the enamel pellicle and thereby early dental plaque formation are largely unknown. The aim of this study was to examine if exposed root surfaces could affect pellicle and initial dental plaque formation on the enamel surface by the analysis of proteins and early adhering bacteria binding to the exposed root surfaces and to the adjacent, gingival enamel surface. Supragingival pellicle and plaque samples were taken from exposed root surfaces and the adjacent enamel surfaces in eleven surgically treated periodontitis patients. For comparison, samples were taken from enamel surfaces of teeth not in need of treatment. Additionally, subgingival bacterial samples were taken. Pellicle proteins were analysed by SDS-PAGE, immunoblotting and image analysis, and bacterial samples by culturing. Significantly more plasma proteins and bacteria were found on the exposed root surfaces than on the enamel. The depth of the gingival recessions was negatively correlated to the amount of plasma proteins in the enamel pellicle. Actinomyces spp. were most frequently found on the exposed root surfaces. The total viable counts and streptococci (%TVC) were positively correlated between subgingival samples and samples from the root surface and enamel of surgically treated teeth. A positive correlation was also found for the findings of Gram-negative anaerobes in subgingival samples and samples from the enamel surface. Our findings suggest that an exposed root surface has binding properties different from an enamel surface and could affect early biofilm formation on the adjacent enamel surface.

Effects of high-fluoride dentifrice (5,000-ppm) on caries-related plaque and salivary variables.

OBJECTIVES: The aim of the present study was to measure the effects of a 5,000-ppm F toothpaste on caries-related factors in dental plaque and saliva. MATERIALS AND METHODS: A 6-week clinical trial was designed with a total of 34 participants, of which 26 completed the study. The participants were assessed on four visits, 2 weeks apart. Sampling of approximal fluid for fluoride analysis and approximal plaque for organic acid analysis was performed. Chair-side tests were performed to register the lactic acid production rate on the tongue using Clinpro™ Cario L-Pop™, approximal plaque pH using the pH "strip method" and salivary buffer capacity and counts of cariogenic microorganisms using CRT Buffer(®) and CRT Bacteria(®). RESULTS: Six weeks' use of 5,000-ppm fluoridated (F) toothpaste significantly increased the approximal fluid F concentration (p < 0.05). There was a significant decrease in lactic acid production rate on the tongue assessed by Clinpro™ (p < 0.05). This was accompanied by changes in interproximal plaque acidogenicity, including significant reductions in AUC(5.7), AUC(6.2) and maximum pH fall and an increase in minimum pH (p < 0.05). A significant increase in the salivary buffer capacity and a reduction in the salivary mutans streptococci were observed (p < 0.05). CONCLUSION: The present study demonstrates the ability of 5,000-ppm F toothpaste to modify caries-related factors in dental plaque and saliva. CLINICAL RELEVANCE: The 5,000-ppm F toothpaste could be regarded as a possible effective regimen against caries in the near future.

pH and bacterial profile of dental plaque in children and adults of a low caries population.

OBJECTIVE: This study compares pH and microbiological profile of dental plaque in children and adults of a low caries population. MATERIAL AND METHODS: Thirty-nine children, 12-14 years of age and 45 adults between 20 and 39 years of age in 5 Karen villages of the Tak province, Northern Thailand were examined for plaque, calculus, caries (DMFT) and pH measurements in resting plaque and after a sucrose rinse. Information on dietary and oral hygiene habits was obtained through interviews using a fixed questionnaire. Microbiological profile of plaque samples was analyzed with DNA-DNA checkerboard technique. RESULTS: Mean DMFT was 0.77 ± 1.56 and 87% of the adults and 67% of the children were caries free (p < 0.05). The mean resting pH was for both age groups in the range of 7.0-7.1 and significantly higher than a Swedish caries free reference group. Karen adult men had significantly lower pH minimum than females and children (p < 0.05). Supragingival plaque samples showed high levels of low acidogenic and anaerobic species, which dominated over strong acid producers such as streptococci. CONCLUSION: The study indicates that the Karen children and adults has a plaque physiology and microbiology predominating by low acidogenic anaerobes, which in addition to the low sucrose intake explains the low caries prevalence in this population.

Caries-risk profile variations after short-term use of 5000 ppm fluoride toothpaste.

OBJECTIVE: To assess the caries risk following 6 weeks' use of 5000 ppm F toothpaste using 'Cariogram' software. MATERIALS AND METHODS: A total of 34 participants, 17 mothers and their teenage children, were enrolled in a 6-week clinical trial in which they were given 5000 ppm F toothpaste. They were followed consecutively for 6 weeks with visits that were 2 weeks apart (four in total). A clinical examination was done at baseline and salivary chair-side tests to record the buffer capacity and mutans streptococci (MS) and lactobacilli (LB) counts were performed at each visit. Based on these data, seven caries-related variables were collected and inserted into the Cariogram software to calculate the actual chance of avoiding caries. RESULTS: The use of 5000 ppm F toothpaste resulted in a statistically significant modification of the caries-risk profile, increasing the actual chance of avoiding caries in the future among the mothers and teenagers at each visit following baseline (p < 0.01). The changes essentially related to the salivary parameters (buffer capacity, MS and LB counts). A statistically significant linear trend was observed for MS counts (p < 0.01) and the number of subjects with a salivary concentration of MS < 10(3) increased at each visit. The same trend was also observed for LB and buffer capacity scores (p = 0.04 and p = 0.03, respectively). CONCLUSIONS: The short-term use of 5000 ppm F toothpaste is able to reduce the caries risk, which can be clearly demonstrated using 'Cariogram' software.

Bacterial markers vs. clinical markers to predict progression of chronic periodontitis: a 2-yr prospective observational study.

The aim of this study was to identify sites at risk for future progression, during 2 yr of maintenance, in patients with chronic periodontitis (CP), based on longitudinal clinical and microbiological monitoring. At baseline (2003), clinical and microbiological features were recorded in 50 patients with CP. Two microbial samples were obtained from each patient (one from a clinically healthy site and one from a periodontitis site) and these were analyzed using DNA-DNA hybridization involving 25 bacterial species. After non-surgical periodontal therapy, clinical and microbiological re-examinations were performed at the same or similar sites at 2 yr (2006) and 4 yr (2008) of maintenance. Plaque, bleeding on probing (BoP), and the number of sites with periodontitis (≥4 mm) and severe periodontitis (≥6 mm) all showed a significant decrease at 2 and 4 yr of maintenance after non-surgical intervention. Checkerboard analysis revealed that various bacteria with a high colonization score (≥3) corroborated the clinical findings of pathology at 2003, 2006, and 2008. Different clusters of bacteria, not just the 'red complex', were able to predict progression of chronic periodontitis during 2 yr of maintenance (2006-2008). Therefore, quantified bacterial markers (reflecting bacterial load) and the clinical markers BoP and periodontal probing depth show comparable prediction of future disease condition.

Fermentation of sugars and sugar alcohols by plaque Lactobacillus strains.

OBJECTIVE: The objective was to analyse the ability of Lactobacillus strains isolated from supragingival plaque of subjects with hyposalivation and from healthy controls to ferment sugars and sugar alcohols. MATERIAL AND METHODS: Fifty strains isolated from interproximal plaque from subjects with radiation-induced hyposalivation (25 strains), subjects with primary Sjögren's syndrome (16 strains) and from subjects with normal salivary secretion rate (9 strains) were tested. Growth and pH were determined after 24 and 48 h of anaerobic incubation in vials containing basal media with 1 % of glucose, fructose, sucrose, mannitol, sorbitol or xylitol. RESULTS: No differences between strains isolated from hyposalivated subjects and controls were detected. All strains lowered the pH to <5.0 from fructose and the majority of the strains from glucose and sucrose. A pH of <5.5 was seen for 52 % of the strains using mannitol, 50 % using sorbitol and 36 % using xylitol. The ability to produce acids from sugars and sugar alcohols was highest among strains of Lactobacillus rhamnosus, Lactobacillus casei and Lactobacillus paracasei and lowest among Lactobacillus fermentum strains. CONCLUSION: A large number of Lactobacillus strains are able to ferment not only sugars but also the sugar substitutes mannitol, sorbitol and xylitol to pH levels critical for enamel demineralisation. CLINICAL RELEVANCE: Our findings suggest that products containing mannitol, sorbitol and/or xylitol may contribute to the acidogenic potential of the dental plaque and especially in hyposalivated subjects with high numbers of lactobacilli.

Supragingival plaque microbial analysis in reflection to caries experience.

BACKGROUND: Dental caries develops as a result of the metabolism of carbohydrates by cariogenic bacteria present in a complex biofilm. The present study aimed to examine if bacteria in pooled supragingival plaque samples quantified using a "checkerboard DNA-DNA hybridization" based panel of caries-related bacteria, could reflect the caries experience in a manner similar to saliva samples analysed using a chair-side method in a previous investigation. METHODS: A total of 86 mothers and their children aged 4-6 years and 12-16 years old participated. Caries experience (DMFT/dmft; Decayed, Missing and Filled Teeth for permanent and primary teeth) was registered clinically and radiographically. Caries was recorded at the D3 level (caries into dentine). The D/d component was divided into three categories. A pooled supragingival plaque sample per participant was obtained from posterior approximal sites. Analyses of 15 bacterial species were performed using the checkerboard DNA-DNA hybridisation technique. RESULTS: No significant relationships were found between the bacterial scores and DMFT/dmft nor D/d groups. CONCLUSIONS: Unlike the saliva samples and the chair-side method, interproximal pooled plaque samples analysed using the "checkerboard DNA-DNA hybridization technique" did not reveal any significant relations between the bacterial counts and the caries experience.

Pellicle and early dental plaque in periodontitis patients before and after surgical pocket elimination.

OBJECTIVE: Gingival inflammation may affect the composition of the dental pellicle and initial acquisition of bacteria, which in turn could affect the healing of the periodontal pocket. The aim of this study was to examine the dental pellicle and early supragingival biofilms in periodontitis patients with an established subgingival infiltrate before and after surgical pocket elimination. MATERIALS AND METHODS: Eleven patients with remaining pockets were selected. Samples were taken before and after surgical pocket elimination and after subsequent experimental gingivitis. Pellicle proteins were analyzed by SDS-PAGE, immunoblotting and image analysis and 4-h supragingival plaque by culturing. RESULTS: The inflammatory status affected to a greater extent the concentration of plasma proteins than salivary proteins in the dental pellicle. The highest plasma protein concentrations were observed at remaining periodontal pockets where also the highest bacterial counts were found. The TVC was reduced on the gingival tooth surfaces (p < 0.05) after pocket elimination and increased slightly during experimental gingivitis. The finding of streptococci was highest on the incisal tooth surfaces and increased after surgery. Gram-negative anaerobes were sparse but seen more often before than after pocket elimination and on gingival than on incisal surfaces. CONCLUSIONS: This study suggests that increased amounts of plasma proteins in the pellicle formed in the presence of remaining periodontal pockets may foster the acquisition of bacteria, including proteolytic Gram-negative species. This, in turn, results in an increased de novo plaque formation rate.

A prospective study on oral microbial flora and related variables in dentate dependent elderly residents.

OBJECTIVE: Oral microorganisms and related variables were followed over a 1-year period in dentate dependent elderly. BACKGROUND: For nursing personnel, oral hygiene for the dependent elderly is demanding. It requires good knowledge of how to carry out preventive oral health measures and to judge when help is needed. Previous studies indicate low levels of knowledge, which might be reflected in the oral health of dentate residents. MATERIAL AND METHODS: Twenty-one subjects participated at baseline and 14 one year later. Microbial samples were analysed using cultivation technique. The labial minor gland secretion rate was measured using the Periotron(®) method, and oral clinical data were registered. RESULTS: Low labial mucosal flow rates were seen for 95% of the participants. At baseline, visibly thick plaque was seen in 48% and 1 year later in 57%. Both frequency and number of bacteria associated with caries and frequency of microorganisms associated with oral soft tissue infections were high. One year later, a decrease in bacteria associated with good oral health and a tendency to an increase in aciduric microorganisms were seen. CONCLUSION: Poor oral health, tending to further deteriorate over time, advocates regular professional supplementary support when elderly dentate dependent residents need assistance with their oral care.

An update on minor salivary gland secretions.

In this article, the literature on minor salivary gland secretion rates, composition, and function is reviewed. Measurements of the minor salivary gland secretion rates and composition are complicated, and the secretions display large biological variability. Despite this, some characteristics of these secretions have been found repeatedly in independent investigations. Minor gland saliva varies between different oral sites. Buccal saliva flow is higher than labial saliva flow, which in turn is usually higher than the palatal gland secretion rate. It is generally agreed that minor gland saliva is important for the whole saliva composition, and especially for the secretory immunoglobulin A and mucins. The secretion from these glands seems also important for subjective feelings of dry mouth and general wellbeing. Further research is essential for understanding the role of these secretions for oral, as well as for general, health.

The 'strip method': a simple method for plaque pH assessment.

AIM: The aim of the study was to evaluate if pH indicator strips could be used for measurements of plaque pH acidogenicity in situ. METHOD: Interproximal plaque pH was measured before and up to 60 min after a 10% sucrose rinse in 30 healthy volunteers using pH indicator strips and the microtouch method in parallel. RESULTS: It was found that the 'strip method' could determine changes in plaque pH to the same extent as the microtouch method (correlation coefficient 0.99). CONCLUSION: Since the 'strip method' is inexpensive and easy to handle, it may be applicable for assessment of plaque acidogenicity in the clinic.

A microbiological study in relation to the presence of caries and calculus.

OBJECTIVE: To examine whether oral microflora in individuals with caries differs from that of individuals with calculus in Thai adolescents with poor oral hygiene. MATERIAL AND METHODS: One hundred 13-year-old schoolchildren from Southern Thailand were examined for the presence of caries, calculus and plaque and saliva pH was also determined. Saliva samples were analysed by culture and approximal supragingival plaque samples were analysed with the DNA-DNA hybridization method ('checkerboard'). RESULTS: Among the 100 children, mean DMFS was 3.43 [standard deviation (SD) 2.82] and 90% had calculus. The correlation between DMFS and the calculus index was 0.064. A total of 36 children were caries-free and 56 had calculus including teeth other than those in the lower anterior region (calculus score > or =3). A total of 23 caries-free children with a high calculus score (> or =3) were compared with 22 children with the highest DMFS [mean 11.19 (SD 5.58)] and a calculus score < 3. No significant difference was obtained for saliva and plaque pH. The salivary levels of mutans Streptococci and Lactobacilli were low. Significantly more children in the caries group had high levels of glycolytic Prevotella nigrescens and Filifactor alocis in plaque compared with the calculus group. Calculus cases had a significantly higher total viable count in saliva. CONCLUSIONS: There was no inverse correlation between the presence of caries and calculus at a population level and a high calculus score only marginally reduced the individual likelihood of having caries. Several glycolytic bacteria were related to caries, while no specific bacteria could be related to calculus formation. Calculus seemed to be more closely related to poor oral hygiene.

Equine saliva components during mastication, and in vivo pH changes in the oral biofilm of sound and carious tooth surfaces after sucrose exposure.

BACKGROUND: The role of saliva composition and dietary sugar in development of infundibular caries in equine cheek teeth is not fully understood. This study analysed electrolyte and urea concentrations in saliva in relation to different forage and measured pH changes after sucrose application in vivo in sound and carious cheek teeth. RESULTS: Forage type had no effect on the equine saliva electrolyte concentrations, which varied considerably both intra- and inter-individually. Chewing resulted in increased values for all electrolytes except bicarbonate. Compared with stimulated human saliva, horse saliva after mastication, contained higher amounts of potassium, calcium and bicarbonate, and less phosphate. The in vivo pH measurements showed a lower resting pH and a more pronounced pH drop after sucrose application in carious teeth compared to sound teeth. CONCLUSIONS: No large differences were found between the composition of equine saliva and human saliva. A more pronounced acidogenicity was found for the carious than sound teeth. Thus, the caries process in equine cheek teeth seems to follow the same pattern as in human teeth, caused by acid production by oral microorganisms after sugar consumption.

Reduced sialyl-Lewisx on salivary MUC7 from patients with burning mouth syndrome.

We analysed and compared MUC7 O-glycosylation and inflammatory biomarkers in saliva from female patients with burning mouth syndrome (BMS) and gender/age-matched controls. Oligosaccharides from salivary MUC7 from BMS and controls were released. Inflammatory mediators were measured by multiplex proximity extension assay. Presence of sialyl-Lewisx (Si-Lex) epitope on MUC7 was confirmed using Western blot. MUC7 O-glycans and measured inflammatory biomarkers were found to be similar between BMS and controls. However, oligosaccharides sialyl-Lewisx (Si-Lex) was found to be reduced in samples from BMS patients. Positive correlation (combined patients and controls) was found between levels of C-C motif chemokine 19 (CCL-19) and the amount of core-2 oligosaccharides on MUC7 as well as fractalkine (CX3CL1) and level of sialylation. Patients with BMS were shown to represent a heterogeneous group in terms of inflammatory biomarkers. This indicates that BMS patients could be further stratified on the basis of low-level inflammation. The results furthermore indicate that reduced sialylation of MUC7, particularly Si-Lex, may be an important feature in patients with BMS. However, the functional aspects and potential involvement in immune regulation of Si-Lex remains unclear. Our data suggests a chemokine driven alteration of MUC7 glycosylation.

Proteomics of the acid-soluble fraction of whole and major gland saliva in burning mouth syndrome patients.

OBJECTIVE: In the present study the salivary proteome of burning mouth syndrome patients and healthy subjects was characterized by a top-down proteomic approach and compared to highlight possible qualitative and quantitative differences that may give suggestions about the causes of this pathology which are still unknown. MATERIALS AND METHODS: Resting and stimulated whole saliva, stimulated parotid and submandibular/sublingual saliva samples were collected from burning mouth syndrome patients (n = 16) and age- and gender-matched healthy subjects (n = 14). An equal volume of 0.2% trifluoroacetic acid was added to each sample immediately after collection and the supernatants were analysed by liquid chromatography coupled to electrospray-ionisation mass spectrometry. Proteins and peptides were quantified using a label-free approach measuring the extracted ion current peak areas of the main salivary proteins and peptides. RESULTS: The quantitation of the main salivary proteins and peptides revealed a higher concentration of cystatin SN in resting saliva of burning mouth syndrome patients with respect to healthy controls and no other conspicuous changes. CONCLUSIONS: The reported data showed that the salivary protein profile was not affected, in composition and relative abundance, by the burning mouth syndrome, except for the cystatin SN, a protein up-regulated in several pathological conditions, that might be considered potentially indicative of the disease.

Acid-producing capacity from sugars and sugar alcohols among Lactobacillus isolates collected in connection with radiation therapy.

OBJECTIVE: To investigate the acid-producing capacity from sugars and sugar alcohols of oral Lactobacillus collected in connection with radiation therapy (RT) to the head and neck region. DESIGN: Lactobacillus were collected from the tongue, buccal mucosa and supragingival plaque in 24 patients before, during, and after RT. The acid-producing capacity of Lactobacillus isolates (n=211) was analyzed using a colorimetric fermentation test in microtiter plates. Solutions containing 2% sugars (sucrose, glucose, fructose, lactose) or sugar-alcohols (sorbitol and xylitol) were used. After 24h of incubation, bacterial acid-producing capacity was determined as strong (pH<5), weak (pH ≥5-≤ 6) or low/absent (pH>6). Data regarding intake frequency of sugar-rich products and products with sugar-alcohols was collected. RESULTS: The highest acid-producing capacity using the sugars was seen for isolates collected during RT. Sorbitol was fermented to a higher extent during and post RT, especially among isolates from plaque. Lactobacillus fermenting xylitol showed the highest acid-producing capacity during RT (p<0.05). No statistically significant correlations between stimulated whole salivary secretion rate and acid-producing capacity, or between the intake frequency of sugar-rich products or sugar-alcohol containing products and Lactobacillus acid-producing capacity, were found. CONCLUSION: The results suggest that Lactobacillus isolates, collected from the tongue, buccal mucosa and supragingival plaque, have a higher acid-producing capacity using sugars and sugar-alcohols during RT than one year post RT.