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Salivary levels of five microorganisms of root caries in nursing home elderly: a preliminary investigation

BMC Oral Health volume 23, Article number: 355 (2023) Cite this article

Abstract

Background

Streptococcus, Bifidobacteria, Lactobacillus and Actinomyces are acidogenic aciduria that may be associated with root caries (RC). The aim of the study was to analyze Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), Bifidobacterium spp., Lactobacillus spp. and Actinomyces naeslundii (A. naeslundii) in the saliva of nursing home elderly, to assess the correlation between bacterial composition and RC for five putative catiogenic organisms.

Methods

In this study, we collected 43 saliva samples and divided into two groups: the root caries group (RCG, n = 21) and the caries-free group (CFG, n = 22). Bacterial DNA was extracted from the saliva samples. The presence and abundance of the five microorganisms were detected by Quantitative real-time PCR (qPCR). Spearman correlation test was performed to evaluate the relationship between the numbers of root decayed filled surfaces (RDFS) and root caries index (RCI) and salivary levels of the bacteria.

Results

The salivary levels of S. mutans, S. sobrinus, Bifidobacterium spp. and Lactobacillus spp. were significantly higher in RCG than in CFG (p < 0.05). RDFS and RCI (RDFS/RCI) were positively associated with salivary levels of S. mutans, S. sobrinus and Bifidobacterium spp. (r = 0.658/0.635, r = 0.465/0.420 and r = 0.407/0.406, respectively). No significant differences in presence and amounts of A. naeslundii was observed between the two groups (p > 0.05).

Conclusion

S. mutans, S. sobrinus and Bifidobacterium spp. in saliva appear to be associated with RC in the elderly. Taken together, the findings indicate that specific salivary bacteria may be involved in the progression of RC.

Peer Review reports

Background

The global elderly population is increasing. The China Seventh Population Census has shown that the number of older people aged 60 years and over has reached 264 million, accounting for 18.7% of the total population [1]. Multiple studies have reported a much higher prevalence of RC in older adults with dental problems than other adult populations [2]. RC is an important public oral health facing human beings due to the improvements of medical health care level and the extension of life expectancy, and the demand for maintaining oral health is increasing [3, 4] .

The pathogenesis of RC is affected by many factors, among which microorganisms play an important role [5]. There is no consensus on the microbial etiologic of RC in the elderly. Previous studies of the microbiota associated with RC have shown that bacteria associated with the disease include Streptococcus, Actinomyces and Bifidobacteria [6, 7]. Several reports have demonstrated that S. mutans is more prone to plaque formation on decaying surfaces compared to healthy root surfaces when used alone or in combination with Lactobacillus spp [8, 9]. Using molecular techniques, Preza et al. showed that the putative RC pathogens including S. mutans, Lactobacillus and Actinomyces and others [4]. Unfortunately, several studies have failed to link specific species to the etiologic of RC [10,11,12].However, comparing the results of different studies appears to be difficult due to differences in methods, samples, and analyses. Oral bacteria were identified using varieties of methods, including but not limited to culture, direct enzyme tests, enzyme-linked immunosorbent assays, denaturing gradient gel electrophoresis, DNA probes and 454-pyrosequencing. qRT-PCR has been used widely used for the detection of targeted microorganisms and the assessment of human oral bacterial colonization due to its advantages of reliability, rapidity, simplicity and economy [13,14,15,16,17,18,19].

Knowledge of the relationship between oral bacteriology and RC is limited, although several studies have qualitatively and quantitatively described the microbiology of RC in the elderly, almost all studies have focused on plaque rather than saliva [7, 20,21,22]. Furthermore, the temporal stability of the saliva microbiome and the easy availability of saliva were considered as the most appropriate probes to provide information about the entire oral microbial population [23, 24]. To our knowledge, few studies have used culture-independent assays to characterize distinct microbial population in the saliva of the elderly with RC. Therefore, the aim of this study was to identify five putative-cariogenic bacteria, namely S. mutans, S. sobrinus, Bifidobacterium spp., Lactobacillus spp. and A. naeslundii in the saliva of nursing home elderly with RC using qRT-PCR assay. We hypothesized that the five target microorganisms would be significantly more abundant in the saliva of the root caries group (RCG) than in the caries-free group (CFG). Secondly, we predicted that the amounts of these bacteria in saliva would correlate with the severity of RC.

Methods

Subject population

This study was approved by the Human Ethics Research Committee of the Hospital of Stomatology, Wuhan University (Approval No. 2011-0030). To have an 80% chance of detecting a difference of 0.2 as significant (at the two-side 5% level), a sample size of 15 subjects was calculated. Based on the assumption of a follow-up dropout of 20%,18 subjects per group were required. Finally, 43 subjects (19 women and 24 men) were recruited from two nursing homes in Wuhan (China) conducted in April,2018 in the study. Informed consent was obtained from all subjects. The inclusion criteria included a minimum age of 60 years, at least 20 existing natural teeth, willingness to participate in the research, no antibiotic therapy or professional cleaning within the past 3 months, not on immunosuppressant medications or steroids, no dry mouth symptoms, no diabetes or human immunodeficiency virus. The subjects were required to exhibit at least one root surface caries tooth to be included in RCG and no coronal caries or RC to be included in CFG.

Clinical examination and questionnaires

All subjects were clinically examined with the aid of a mirror and a ball-ended WHO Community Periodontal Index probe by two calibrated dental epidemiologists in the dental clinic with the assistance of trained recorder. RC definition and diagnosis were based on the criteria of the World Health Organisation [25]. A lesion on an exposed root surface was classified as RC if it felt soft or leathery on probing. Clinical oral health status was measured using root decayed filled surfaces (RDFS) [25], root caries index (RCI) [26], the community periodontal index (CPI) and the number of remaining teeth (NRT). The kappa coefficients for the indices of RDFS and CPI were 0.80 and 0.77.

After clinical examination, questionnaires referring to the tooth brushing habits, sugar intake per week and smoking of each subject were recorded.

Sampling and extraction of genomic DNA

Sampling was performed after oral examination. All subjects were asked to avoid eating or drinking for 1 h before oral sampling. Unstimulated saliva samples of at least 2 mL were collected from each subject. All saliva samples were packed in coolers with cold packs supplemented with ice and transported to the laboratory within 3 h, where they were frozen at − 80 °C until further analysis.

Total bacterial genomic DNA was extracted from each saliva sample using the modification of the Epicentre method (Epicentre, Madison, WI, USA) according to published protocol [27]. The final quantity and quality of DNA was evaluated using ND-1000 at OD260/OD280. A standard concentration of 10 ng/µL was prepared for each sample for all qRT-PCR assays.

Bacterial strains and media

The five oral bacterial strains included S. mutans strain ATCC 700,610, S. sobrinus strain 6715, Bifidobacterium dentium (B. dentium) strain ATCC 27,534, Lactobacillus acidophilus (L. acidophilus) strain ATCC 4356 and (A) naeslundii strain ATCC 12,104. Strains of (B) dentium ATCC 27,534 (order No. ATCC 27,534) and L. acidophilus ATCC 4356 (order No. ATCC 4356) and genomic DNA of S. mutans ATCC 700610D (order No. ATCC 700610-5) and A. naeslundii ATCC 12104D (order No. ATCC 12104-5) were directly purchased from the American Type Culture Collection (ATCC, Manassas, VA, USA). S. sobrinus strain 6715 was purchased from China Center for Type Culture Collection (CCTCC, Wuhan, China). The selected stains were incubated under the anaerobic conditions at 37 °C using mediums of brain heart infusion (Becton Dickinson, NJ, USA), tryticase phytone glucose (Hopebio, Qingdao, China) and lactobacilli MRS (Becton Dickinson, NJ, USA). Genomic DNA preparations from each strain, except S. mutans and A. naeslundii, were obtained using the method above and then purified.

qRT-PCR assays

Amplification and quantification were performed with an ABI 7500 system (Applied Biosystems, Foster City, CA, USA). The qRT-PCR mixture containing a total volume of 20 µL consisted of 10 µL of 2X SYBR Premix DimerEraser (Takara, Shiga, Japan), 0.4 µM of each forward and reverse primer, 0.4 µL of 50X ROX and 2.5 µL of the template DNA. Each sample and standard was tested in duplicate and the final analysis was based on the mean of the two reactions. The thermal cycling conditions for all qRT-PCR assays were as follows: 95 °C for 2 min, followed by 40 cycles at 95 °C for 5 s, 60 °C for 60 s for S. mutans, S. sobrinus and Lactobacillus spp. and A. naeslundii. The cycling conditions for Bifidobacterium spp. were as follows: 95 °C for 2 min, followed by 40 cycles at 95 °C for 5 s, 58 °C for 30 s and 72 °C for 60 s. The specific primers used for qRT-PCR are listed in Table 1.

The quantity of DNA was calculated from standard curves (Fig. 1) for each bacterial species, using DNA controls from standard bacterial cultures, which Were diluted from series of 10-fold. After the final cycle of qPCR, analysis of the cycle threshold (CT) and melting temperature (Tm) values were carried out in all the amplified samples. Samples were considered negative for bacterial species when their CT and Tm values were below the level of detection in the curves of DNA standards. All values were measured in duplicate and linearity was reproduced in a second run.

Table 1 Species-specific primers for real-time qPCR assay
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Fig. 1
figure 1

Standard curves of the known bacterial

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Statistical analysis

The qRT-PCR results were organised and analysed using the SPSS 19.0 statistical software package (SPSS Inc., Chicago, IL, USA). Descriptive statistics, including prevalence, mean, range, standard deviation, standard error and variance, were examined. Nonparametric Mann–Whitney U test was used to examine the significance of distribution among continuous variables. Fisher’s exact test was used to examine the significance of distribution among categorical variables. Spearman correlation test was used to examine the correlation coefficients between the salivary levels of bacteria and the indices of RDFS and RCI. A p value less than or equal to 0.05 was considered statistically significant.

Results

General results

Demographic and clinical characteristics of the study population was showed in Table 2. The mean NRT was significantly higher in CFG (25.8) than in RCG (23.7; p = 0.007). Age, gender, CPI scores, oral hygiene/day, sugar intake/week and smoking between the two groups were not statistically significant (p > 0.05).

Table 2 Demographic and clinical characteristics of the study population
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Prevalence of the five bacteria in RCG and CFG

Table 3 shows the prevalence of the five targeted bacteria. Among the five bacteria examined, S. sobrinus had significantly higher prevalence in RCG (47.6%) than in CFG (18.2%; p = 0.039). Whilst the positive prevalence of S. mutans and Bifidobacterium spp. in RCG was higher than that in CFG, differences between the two microorganisms were not statistically significant (p = 0.079 and p = 0.052, respectively). Lactobacillus spp. and A. naeslundii were positive in all of the subjects.

Table 3 Prevalence of the five targeted microorganisms in RCG and CFG saliva
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We further analysed the co-prevalence of bacterial taxons from saliva in RCG and in CFG (Fig. 2). The co-occurrences of S. mutans & S. sobrinus, S. mutans & Bifidobacterium spp., S. sobrinus & Bifidobacterium spp. & S. mutans, S. sobrinus & Bifidobacterium spp. were found to be significantly more frequent in RCG than in CFG (p < 0.05).

Fig. 2
figure 2

Co-prevalence of bacterial taxons from saliva in RCG and in CFG. The co-occurrences of S. mutans & S. sobrinus, S. mutans & Bifidobacterium spp., S. sobrinus & Bifidobacterium spp. & S. mutans, S. sobrinus & Bifidobacterium spp. were found to be significantly more frequent in RCG than in CFG (p < 0.05). (* p < 0.05, ** p < 0.01)

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Salivary levels of the five targeted microorganisms in RCG and CFG

The salivary levels of the five targeted microorganisms between the two groups were evaluated (Table 4). The salivary levels of all five targeted bacteria in RCG were higher than those in CFG. S. mutans, S. sobrinus, Bifidobacterium spp. and Lactobacillus spp. were significantly higher in RCG than in CFG (p < 0.05). No significant differences in A. naeslundii were observed between the two groups (p > 0.05).

Table 4 Comparison of the mean DNA levels log10 (cells/ml + 1) of targeted microorganisms between the RC and CFG
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The relative ratio of each species within the total five species from RCG and CFG was shown in Table 5. A. naeslundii showed higher ratio in CFG than in RCG. By contrast, the four other bacteria showed greater ratio in RCG than in CFG.

Table 5 Frequencies of each of the five species in RCG and CFG saliva
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Correlation between the five bacteria and RDFS index and RCI in both groups

The correlation between the RDFS index and RCI and salivary levels of bacteria were calculated. The correlation coefficients (r) between RDFS and S. mutans, S. sobrinus, Bifidobacterium spp., Lactobacillus spp. and A. naeslundii were 0.658, 0.465, 0.407, 0.271 and − 0.065, respectively. As well, r values between RCI and the corresponding microorganisms were 0.635, 0.420, 0.406, 0.252 and − 0.044, respectively (Table 6).

Table 6 Correlations between the RDFS index and RCI and salivary levels of bacteria
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Discussion

RC is a significant oral health issue, especially in the elderly. Detailed information on the composition of oral microbiota in relation to dental caries may aid in assessing the individual’s risk and better understanding the etiology. Here, we used qRT-PCR to analyze the bacterial composition of five putative-cariogenic microorganisms in the saliva of nursing home elderly subjects with RC for the first time.

For a long time, RC was thought to be induced specifically by Actinomyces [6, 30]. A. naeslundii, one of the most common species of Actinomyces, has been demonstrated to be related to RC [10, 31]. In contrast, other studies have showed that A. naeslundii might play beneficial roles as well [32, 33]. Other study indicate that some bacteria, frequently related to oral health, have been also involved with dental caries, then being considered as alternative pathogens such as A. naeslundii [33]. Interesting, in the present study, no statistical difference was observed among the two groups for A. naeslundii, which is consistent with previous literature reports [19]. A naselundii has been considered as probiotics because some of their metabolic activities may modulate dynamic caries processes in a different way, such as the use of lactate as a carbon source [34]. Another study showed that A. naeslundii may have inhibited S. mutans growth [35]. Consequently, the molecular mechanisms through which these microorganisms participate in caries initiation remain unclear and further studies are needed to identify the ecological shifts leading to cariogenic biofilms [36].

Mutans streptococci (MS, S. mutans and S. sobrinus) were the investigated carious bacteria in the past [8, 9, 14,15,16, 18]. In the present study, both S. mutans and S. sobrinus were detected. Our results showed that the prevalence rates of S. mutans and S. sobrinus were higher in RCG than in CFG, but a statistically significant difference was found only for S. sobrinus (Table 3). Meanwhile, we observed that the co-prevalence of S. sobrinus and S. mutan was 48% in our study. Similar results have been described in the Oda et al.’ study, they report that both S.mutans and S.sobrinus were found positive in 58% individuals [37]. However, the results of different studies are still controversial. In accordance with N.M. Nurelhuda et al.’ study, S. sobrinus was never present alone and was always detected alongside with S. mutans [15]. While Franco et al. reported zero prevalence of both the species residing together in study individuals [38]. In our qRT-PCR analyses, significantly higher amounts of S. mutans and S. sobrinus were observed in RCG than in CFG (Table 4), which is in accordance with results of previous studies on coronal caries [14, 39] and RC [20]. In addition, we found that the salivary levels of S. mutans and S. sobrinus were positively correlated with the indices of RDFS/RCI (Table 6), implying that abundance of S. mutans and S. sobrinus increased with severity of RC. These findings suggest that S. mutans and S. sobrinus may be involved in some progression of RC and hence considered as meaningful bio-markers for assessing the risk of RC.

Bifidobacteria are acidogenic and aciduric microorganisms that have recently been verified to be related to coronal caries in children and adults [19, 29], as well as clinical severity of RC [7]. As shown in Fig. 1, the co-prevalence of S. mutans & Bifidobacterium spp., S. sobrinus & Bifidobacterium spp. and S. mutans & S. sobrinus & Bifidobacterium spp. were manifested significantly higher in RCG than in CFG. Therefore, co-occurrence with multi-bacteria may be valuable in risk assessment of dental caries, which is consistent with the findings of Tanner et al [40]. Using culture-based methods, Mantzourani et al. and Kaur et al. found that Bifidobacteria were positively related to the RC in the plaque [7] and coronal caries in the saliva [39], respectively. Our observation that the amounts of Bifidobacterium spp. were significantly higher in RCG than in CFG validates this finding. We also found that the severity of RC measured by RDFS/RCI correlated positively with the salivary levels of Bifidobacterium spp. Taken together, these findings confirm our hypothesis and suggest that Bifidobacterium spp. may contribute to the etiologic of RC. Actually, Species in Scardovia, a genus in the Bifidobacterium family, have been identified in cavitated dentin lesions in addition to Streptococcus and Lactobacillus [41]. Santos et al. found that associations of B. animalis and B. longum with streptococci promoted EPS production and caries lesion progression [42]. These observations give importtant insights into the influences between Bifidobacteria and streptococci, which should be addressed in the future.

Among the five selected microorganisms analysed in this study, the highest bacteria load was that of Lactobacillus spp. (Table 4). Lactobacilli have been extensively reported to be involved in caries progression [43,44,45]. Our quantitative results demonstrated that the salivary level of Lactobacillus spp. was significantly higher in RCG than in CFG (Table 5), which does agree with previous studies [20, 29]. However, the salivary level of Lactobacillus spp. did not correlate positively with the indices of RFDS and RCI (Table 6), indicating that the abundance of lactobacilli did not increase with the growing severity of RC. This is consistent with previous studies [18, 19]. Contrastly, Lapirattanakul et al. found that the detection of oral lactobacilli together with S. mutans was related to highest dental caries severity and Lactobacillus fermentum was the most prevalent, and its presence was related to high scores of caries [46]. Nevertheless, it should be noted that more well-designed studies aimed at specific species of lactobacilli are necessary to further test the relationship between the bacteria and RC.

qRT-PCR analysis provided a sensitive, rapid, reliable and simple method for quantification of bacteria. Although specific primers were eligible for identification of the target microorganisms, our results may still be confounded by primer bias. For example, in the case of Bifidobacterium spp., the primers not only cover the targeted genera, but also recognize other oral Bifidobacteria such as Scardovia, Parascardovia and Gemella. Another limitation of this study is that only five microorganisms were selected, which may not be sufficient to uncover the relation between all the microorganisms and RC. Although our data are valid and substantial enough to meet the aim of our study, further studies involving more taxons are needed and recommended.

Conclusions

In summary, using qRT-PCR assay, we first demonstrated bacterial composition of five bacteria in the saliva of elderly with RC. The first study hypothesis that the selected putative-cariogenic microorganisms would be found to be significantly more abundant in RCG than CFG was confirmed for S. mutans, S. sobrinus, Bifidobacterium spp. and Lactobacillus spp. The second study hypothesis that the amounts of five targeted bacteria would be associated with the severity of RC was confirmed only for S. mutans, S. sobrinus and Bifidobacterium spp. Based on our results, S. mutans, S. sobrinus and Bifidobacterium spp. in saliva appear to be associated with RC in the elderly and may act as bio-markers for the risk assessment of RC.

Data availability

The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.

Abbreviations

RC:

Root caries

RCI:

Root caries index

NRT:

Number of remaining teeth

RDFS:

Root decayed filled surfaces

RCG:

Root caries group

CFG:

Caries-free group

CPI:

Community periodontal index

qPCR:

Quantitative real-time PCR

S. mutans :

Streptococcus mutans

S. sobrinus :

Streptococcus sobrinus

A. naeslundii :

Actinomyces naeslundii

B. dentium :

Bifidobacterium dentium

L. acidophilus :

Lactobacillus acidophilus

References

  1. Tu WJ, Zeng X, Liu Q. Aging tsunami coming: the main finding from China’s seventh national population census. Aging Clin Exp Res. 2022;34(5):1159–63.

    Article  PubMed  Google Scholar 

  2. Chan AKY, Tamrakar M, Jiang CM, Lo ECM, Leung KCM, Chu CH. A Systematic Review on Caries Status of Older Adults.Int J Environ Res Public Health2021, 18(20).

  3. Islas-Granillo H, Borges-Yanez SA, Medina-Solis CE, Casanova-Rosado AJ, Minaya-Sanchez M, Villalobos Rodelo JJ, Maupome G. Socioeconomic, sociodemographic, and clinical variables associated with root caries in a group of persons age 60 years and older in Mexico. Geriatr Gerontol Int. 2012;12(2):271–6.

    Article  PubMed  Google Scholar 

  4. Preza D, Olsen I, Aas JA, Willumsen T, Grinde B, Paster BJ. Bacterial profiles of root caries in elderly patients. J Clin Microbiol. 2008;46(6):2015–21.

    Article  PubMed  PubMed Central  Google Scholar 

  5. Martin PDMMV. Oral Microbiology Text and Evolve eBooks Package, 5th Edition. 2009:232.

  6. Papone Yorio V. [Actinomyces. Its relation to dental plaque–root caries–actinomycosis]. Odontoestomatologia. 1989;2(2):47–53.

    PubMed  Google Scholar 

  7. Mantzourani M, Fenlon M, Beighton D. Association between Bifidobacteriaceae and the clinical severity of root caries lesions. Oral Microbiol Immunol. 2009;24(1):32–7.

    Article  PubMed  Google Scholar 

  8. Ellen RP, Banting DW, Fillery ED. Streptococcus mutans and Lactobacillus detection in the assessment of dental root surface caries risk. J Dent Res. 1985;64(10):1245–9.

    Article  PubMed  Google Scholar 

  9. Fure S, Romaniec M, Emilson CG, Krasse B. Proportions of Streptococcus mutans, lactobacilli and Actinomyces spp in root surface plaque. Scand J Dent Res. 1987;95(2):119–23.

    PubMed  Google Scholar 

  10. van Houte J, Lopman J, Kent R. The predominant cultivable flora of sound and carious human root surfaces. J Dent Res. 1994;73(11):1727–34.

    Article  PubMed  Google Scholar 

  11. Shen S, Samaranayake LP, Yip HK, Dyson JE. Bacterial and yeast flora of root surface caries in elderly, ethnic chinese. Oral Dis. 2002;8(4):207–17.

    Article  PubMed  Google Scholar 

  12. Schupbach P, Osterwalder V, Guggenheim B. Human root caries: microbiota of a limited number of root caries lesions. Caries Res. 1996;30(1):52–64.

    Article  PubMed  Google Scholar 

  13. Price RR, Viscount HB, Stanley MC, Leung KP. Targeted profiling of oral bacteria in human saliva and in vitro biofilms with quantitative real-time PCR. Biofouling. 2007;23(3–4):203–13.

    Article  PubMed  Google Scholar 

  14. Choi EJ, Lee SH, Kim YJ. Quantitative real-time polymerase chain reaction for Streptococcus mutans and Streptococcus sobrinus in dental plaque samples and its association with early childhood caries. Int J Pediatr Dent/Br Paedodontic Soc Int Assoc Dent Child. 2009;19(2):141–7.

    Google Scholar 

  15. Nurelhuda NM, Al-Haroni M, Trovik TA, Bakken V. Caries experience and quantification of Streptococcus mutans and Streptococcus sobrinus in saliva of sudanese schoolchildren. Caries Res. 2010;44(4):402–7.

    Article  PubMed  Google Scholar 

  16. Psoter WJ, Ge Y, Russell SL, Chen Z, Katz RV, Jean-Charles G, Li Y. PCR detection of Streptococcus mutans and Aggregatibacter actinomycetemcomitans in dental plaque samples from haitian adolescents. Clin Oral Invest. 2011;15(4):461–9.

    Article  Google Scholar 

  17. Dalwai F, Spratt DA, Pratten J. Use of quantitative PCR and culture methods to characterize ecological flux in bacterial biofilms. J Clin Microbiol. 2007;45(9):3072–6.

    Article  PubMed  PubMed Central  Google Scholar 

  18. Colombo NH, Kreling PF, Ribas LFF, Pereira JA, Kressirer CA, Klein MI, Tanner ACR, Duque C. Quantitative assessment of salivary oral bacteria according to the severity of dental caries in childhood. Arch Oral Biol. 2017;83:282–8.

    Article  PubMed  Google Scholar 

  19. Neves BG, Stipp RN, Bezerra DDS, Guedes SFF, Rodrigues LKA. Quantitative analysis of biofilm bacteria according to different stages of early childhood caries. Arch Oral Biol. 2018;96:155–61.

    Article  PubMed  Google Scholar 

  20. Bizhang M, Ellerbrock B, Preza D, Raab W, Singh P, Beikler T, Henrich B, Zimmer S. Detection of nine microorganisms from the initial carious root lesions using a TaqMan-based real-time PCR. Oral Dis. 2011;17(7):642–52.

    Article  PubMed  Google Scholar 

  21. Preza D, Olsen I, Willumsen T, Boches SK, Cotton SL, Grinde B, Paster BJ. Microarray analysis of the microflora of root caries in elderly. Eur J Clin Microbiol Infect diseases: official publication Eur Soc Clin Microbiol. 2009;28(5):509–17.

    Article  Google Scholar 

  22. Chen L, Qin B, Du M, Zhong H, Xu Q, Li Y, Zhang P, Fan M. Extensive description and comparison of human supra-gingival microbiome in root caries and health. PLoS ONE. 2015;10(2):e0117064.

    Article  PubMed  PubMed Central  Google Scholar 

  23. Mager DL, Ximenez-Fyvie LA, Haffajee AD, Socransky SS. Distribution of selected bacterial species on intraoral surfaces. J Clin Periodontol. 2003;30(7):644–54.

    Article  PubMed  Google Scholar 

  24. Luo AH, Yang DQ, Xin BC, Paster BJ, Qin J. Microbial profiles in saliva from children with and without caries in mixed dentition. Oral Dis. 2012;18(6):595–601.

    Article  PubMed  Google Scholar 

  25. WHO. Oral health surveys: basic Methods[M]. Geneva: WHO; 2013.

    Google Scholar 

  26. Corby PM, Lyons-Weiler J, Bretz WA, Hart TC, Aas JA, Boumenna T, Goss J, Corby AL, Junior HM, Weyant RJ, et al. Microbial risk indicators of early childhood caries. J Clin Microbiol. 2005;43(11):5753–9.

    Article  PubMed  PubMed Central  Google Scholar 

  27. Li Y, Ku CYS, Xu J, Saxena D, Caufield PW. Survey of oral microbial diversity using PCR-based denaturing gradient gel electrophoresis. J Dent Res. 2005;84(6):559–64.

    Article  PubMed  Google Scholar 

  28. Childers NK, Osgood RC, Hsu KL, Manmontri C, Momeni SS, Mahtani HK, Cutter GR, Ruby JD. Real-time quantitative polymerase chain reaction for enumeration of Streptococcus mutans from oral samples. Eur J Oral Sci. 2011;119(6):447–54.

    Article  PubMed  PubMed Central  Google Scholar 

  29. Mantzourani M, Gilbert SC, Sulong HN, Sheehy EC, Tank S, Fenlon M, Beighton D. The isolation of bifidobacteria from occlusal carious lesions in children and adults. Caries Res. 2009;43(4):308–13.

    Article  PubMed  Google Scholar 

  30. Sumney DL, Jordan HV. Characterization of bacteria isolated from human root surface carious lesions. J Dent Res. 1974;53(2):343–51.

    Article  PubMed  Google Scholar 

  31. Schupbach P, Osterwalder V, Guggenheim B. Human root caries: microbiota in plaque covering sound, carious and arrested carious root surfaces. Caries Res. 1995;29(5):382–95.

    Article  PubMed  Google Scholar 

  32. Marchant S, Brailsford SR, Twomey AC, Roberts GJ, Beighton D. The predominant microflora of nursing caries lesions. Caries Res. 2001;35(6):397–406.

    Article  PubMed  Google Scholar 

  33. Aas JA, Griffen AL, Dardis SR, Lee AM, Olsen I, Dewhirst FE, Leys EJ, Paster BJ. Bacteria of dental caries in primary and permanent teeth in children and young adults. J Clin Microbiol. 2008;46(4):1407–17.

    Article  PubMed  PubMed Central  Google Scholar 

  34. Takahashi N, Yamada T. Catabolic pathway for aerobic degradation of lactate by Actinomyces naeslundii. Oral Microbiol Immunol. 1996;11(3):193–8.

    Article  PubMed  Google Scholar 

  35. de Oliveira RVD, Bonafe FSS, Spolidorio DMP, Koga-Ito CY, Farias AL, Kirker KR, James GA, Brighenti FL. Streptococcus mutans and Actinomyces naeslundii Interaction in Dual-Species Biofilm.Microorganisms2020, 8(2).

  36. Mattos-Graner RO, Klein MI, Smith DJ. Lessons learned from Clinical Studies: roles of Mutans Streptococci in the Pathogenesis of Dental Caries. Curr Oral Health Rep. 2014;1(1):70–8.

    Article  Google Scholar 

  37. Oda Y, Hayashi F, Okada M. Longitudinal study of dental caries incidence associated with Streptococcus mutans and Streptococcus sobrinus in patients with intellectual disabilities. BMC Oral Health. 2015;15:102.

    Article  PubMed  PubMed Central  Google Scholar 

  38. Franco e Franco TC, Amoroso P, Marin JM, de Avila FA. Detection of Streptococcus mutans and Streptococcus sobrinus in dental plaque samples from brazilian preschool children by polymerase chain reaction. Braz Dent J. 2007;18(4):329–33.

    Article  PubMed  Google Scholar 

  39. Kaur R, Gilbert SC, Sheehy EC, Beighton D. Salivary levels of Bifidobacteria in caries-free and caries-active children.International journal of paediatric dentistry / the British Paedodontic Society [and] the International Association of Dentistry for Children2012.

  40. Tanner AC, Kent RL Jr, Holgerson PL, Hughes CV, Loo CY, Kanasi E, Chalmers NI, Johansson I. Microbiota of severe early childhood caries before and after therapy. J Dent Res. 2011;90(11):1298–305.

    Article  PubMed  PubMed Central  Google Scholar 

  41. Jiang W, Ling Z, Lin X, Chen Y, Zhang J, Yu J, Xiang C, Chen H. Pyrosequencing analysis of oral microbiota shifting in various caries states in childhood. Microb Ecol. 2014;67(4):962–9.

    Article  PubMed  Google Scholar 

  42. Santos VRD, Valdez RMA, Danelon M, Souza JAS, Caiaffa KS, Delbem ACB, Duque C. Effect of S. mutans combinations with bifidobacteria/lactobacilli on biofilm and enamel demineralization. Braz Oral Res. 2021;35:e030.

    Article  PubMed  Google Scholar 

  43. Brailsford SR, Shah B, Simons D, Gilbert S, Clark D, Ines I, Adams SE, Allison C, Beighton D. The predominant aciduric microflora of root-caries lesions. J Dent Res. 2001;80(9):1828–33.

    Article  PubMed  Google Scholar 

  44. Byun R, Nadkarni MA, Chhour KL, Martin FE, Jacques NA, Hunter N. Quantitative analysis of diverse Lactobacillus species present in advanced dental caries. J Clin Microbiol. 2004;42(7):3128–36.

    Article  PubMed  PubMed Central  Google Scholar 

  45. Chhour KL, Nadkarni MA, Byun R, Martin FE, Jacques NA, Hunter N. Molecular analysis of microbial diversity in advanced caries. J Clin Microbiol. 2005;43(2):843–9.

    Article  PubMed  PubMed Central  Google Scholar 

  46. Lapirattanakul J, Nomura R, Okawa R, Morimoto S, Tantivitayakul P, Maudcheingka T, Nakano K, Matsumoto-Nakano M. Oral Lactobacilli related to Caries Status of children with primary dentition. Caries Res. 2020;54(2):194–204.

    Article  PubMed  Google Scholar 

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Acknowledgements

The authors would like to thank all the participants and all the staff who assisted in the survey.

Funding

This research was funded by The Guangdong Medical Research Foundation, grant number A2021296 and B2021050.

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Author notes

  1. Lin Chen and Yuandong Qin contributed equally to this work.

Authors and Affiliations

  1. Stomatological Hospital, School of Stomatology, Southern Medical University, No. 366, South of Jiangnan Avenue, Guangzhou, China

    Lin Chen & Yuandong Qin

  2. The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei- MOST) & Key Laboratory of Oral Microbiology Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China

    Lin Chen, Yuhong Lin, Minquan Du, Yuhong Li & Mingwen Fan

  3. Department of Endodontics, Yantai Stomatological Hospital Affiliated to Binzhou Medical College, Yantai, China

    Yuhong Lin

  4. First dental hospital , Jean Han University, Wuhan, China

    Mingwen Fan

Authors
  1. Lin Chen
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  2. Yuandong Qin
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  3. Yuhong Lin
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Contributions

CL, FMW: Conception and design of the work, conduct the experiment, analysis and interpretation of data. CL, QYD, Lin Yuhong: Drafting the article or revising it critically for important intellectual content. CL, QYD, Lin Yuhong, Li Yuhong, DMQ, FMW: Agreement to be accountable for all aspects of the work. Li Yuhong: Provide assistant with data analysis. All authors have made substantive contribution to this study and/or manuscript, and all have reviewed the final paper prior to its submission. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Mingwen Fan.

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Competing interests

The authors declare that they have no competing interests.

Ethics approval and consent to participate

This study was approved by the the Human Ethics Research Committee of the Hospital of Stomatology, Wuhan University (Approval No. 2011-0030). All procedures performed in the study involving human participants were in accordance with the Helsinki declaration. Informed consent was obtained from all the participants and from legal guardians of illiterate participants.

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Chen, L., Qin, Y., Lin, Y. et al. Salivary levels of five microorganisms of root caries in nursing home elderly: a preliminary investigation. BMC Oral Health 23, 355 (2023). https://doi.org/10.1186/s12903-023-02953-9

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Keywords

BMC Oral Health

ISSN: 1472-6831

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