Original Article
http://dx.doi.org/10.1590/1678-7757-2018-0564

Effect of bovine milk fermented with
Lactobacillus rhamnosus L8020 on
periodontal disease in individuals withintellectual disability: a randomized
clinical trial
Abstract
Yuki ODA1
Chiaki FURUTANI1
Yuika MIZOTA2Atsuko WAKITA2
Sumiyo MIMURA3

Studies on the oral health of individuals with intellectual disability (ID)have identified problems that include a high prevalence of periodontal
disease. The use of probiotics to treat periodontal disease has been thefocus of considerable research, and bovine milk fermented with Lactobacillus
rhamnosus L8020 (L8020 yogurt) has been shown to reduce the oral
prevalence of four periodontal pathogens. Objective: The aim of thisTakuya KIHARA4

randomized, double-blind, placebo-controlled trial was to compare the effects

Masaru OHARA5

of L8020 yogurt (test group) with those of placebo yogurt (placebo group)

Yoshiyuki OKADA1

on the papillary-marginal-attached (PMA) index, gingival index (GI), andMitsugi OKADA1
Hiroki NIKAWA3*

probing depth (PD) in 23 individuals with ID. Methodology: All patients wererequired to consume the allocated yogurt after breakfast for 90 days. PMA
index and GI scores as well as PDs were assessed before the start of yogurt
consumption (baseline), after 45 and 90 days of consumption, and 30 days
after the cessation of consumption. Student’s t-test, Mann–Whitney U test
or Fisher’s exact test was used for inter-group comparisons, and the mixed
effect model of repeated measurements was used for data analysis. Results:
The decrease in PMA index score was significantly greater in the test groupthan in the placebo group (p<0.001). The GI score also decreased during thestudy, with a tendency for greater decrease in the test group. Furthermore,decreases in PD between baseline, 45 and 90 days tended to be greater inthe test group than in the placebo group. Conclusion: These results suggestthat regular consumption of bovine milk fermented with L. rhamnosus L8020
can lower the risk of periodontal disease in individuals with ID.
Keywords: Milk. Intellectual disability. Lactobacillus. Probiotics. Yogurt.
Periodontal diseases.

Submitted: October 10, 2018
Modification: December 17, 2018
Accepted: January 17, 2019
Corresponding address:
Hiroki Nikawa
Department of Oral Biology and Engineering,
Hiroshima University
1-2-3 Kasumi, Minami-ku Hiroshima 734-8553 - Japan.
Phone: +81-82-257-5097 - Fax: +81-82-257-5097
e-mail: hirocky@hiroshima-u.ac.jp

Hiroshima University Hospital, Department of Special Care Dentistry, Hiroshima, Japan.
Hiroshima University Hospital, Department of Clinical Practice and Support, Division of Dental
Hygiene, Hiroshima, Japan.
3
Hiroshima University, Department of Oral Biology and Engineering, Hiroshima, Japan.
4
Tsurumi University, School of Dental Medicine, Department of Fixed Prosthodontics, Yokohama,Japan.
5
Hiroshima University Hospital, Department of Advanced General Dentistry, Hiroshima, Japan.
1
2

J Appl Oral Sci.

1/9

2019;27:e20180564

Effect of bovine milk fermented with Lactobacillus rhamnosus L8020 on periodontal disease in individuals with intellectual disability: a randomized clinical trial

Introduction

by scaling and root planing is an essential aspect of
periodontal therapy, the complete removal of plaqueretentive factors is not always possible,17 particularlyIntellectual disability (ID) is defined as sub-for individuals with ID, who are mostly noncompliant

average general intellectual function and is associatedwith dental treatment. The use of probiotics to promotewith impaired adaptive behavior.1 Many researchers

oral health has been reported in a few studies,18,19

have reported that individuals with ID have worsewith the probiotics used being mostly derived fromoral hygiene and higher rates of dental disease

the intestine. However, data on the effects of probiotic

than ordinary individuals.2-4 Reported oral health-bacteria on periodontal pathogens are limited.16 The

related problems in individuals with ID include poor

aim of this randomized controlled trial was to determine

oral hygiene, progressed dental caries, and a highthe effect of L8020 yogurt on the papillary-marginal-

prevalence of periodontal disease.5 The oral healthattached (PMA) index,20 gingival index (GI),21 andstatus of these patients is affected by their patterns

probing depth (PD) in individuals with ID. The PMAof cognition, developmental age,6 and other factors

index evaluates gingival inflammation according to thesuch as age, the personality and compliance of thedegree of involvement of the interdental papilla as wellcaregiver, and the presence of underlying diseases,

as the marginal and attached gingiva, where GI is theincluding physical disabilities.2 Individuals with ID

number assigned to designate the degree of gingival

experience difficulty in understanding the importanceinflammation. PD precisely assesses the severity ofof oral health and tend to co-operate less for oral

periodontal disease through measurement of thecleaning procedures. Because maintenance of a healthy

periodontal pocket depth using a periodontal probe.

oral environment in patients with ID is not easy,7available measures for the prevention of oral disease
and improvement of oral hygiene in these individuals

Methodology

are limited,8 although necessary.9
The Food and Agriculture Organization/World HealthStudy design

Organization defines probiotics as live microorganismsthat confer a health benefit to the host (i.e. improve

Twenty-three outpatients with ID were enrolled in

the microbial balance in the intestinal tract) when

this randomized, double-blind, placebo-controlled trial.

consumed in adequate amounts (in food or as dietary

The patients were randomly allocated to a L8020 yogurt

supplements).10,11 The use of probiotics for the treatmentgroup (n=12) or a placebo yogurt group (n=11, afterof periodontal disease has been the focus of considerable

one patient withdrew consent before randomization;

Organisms commonly associated with

Figure 1). All patients were required to consume 80 g

periodontal disease include Porphyromonas gingivalis,of the allocated yogurt after breakfast in the morning

research.

12,13

Prevotella intermedia, Tannerella forsythia, Dialisterfor 90 days. During this time, they were instructed topneumosintes, Campylobacter rectus, Fusobacterium

refrain from toothbrushing or consuming any food or

spp, Selenomonas sputigena, Parvimonas micra, andbeverage for 1 h after consumption of the yogurt. The

Nikawa,patients were assessed at baseline (before the start

et al.15 (2004) demonstrated that yogurt containingof daily yogurt consumption), after 45 and 90 days of

Lactobacillus rhamnosus L8020 (L8020 yogurt), which

yogurt consumption, and 30 days after the cessation

has been detected as a normal strain of bacteria in theof yogurt consumption (120 days after the start oforal cavity,16 significantly lowered the risk of dental

consumption). Simple randomization and centralized

caries, suggesting that daily consumption of thisallocation methods were used. A random number

probiotic organism may be useful in the prevention

table was generated by an off-site computer (Shikoku

of caries. L. rhamnosus L8020 is also known to be

Nyugyou, Co. Inc, Toon City, Ehime Prefecture, Japan),

active against a broad spectrum of bacteria that cause

and the assignment table was prepared by the research

periodontal disease.16 Specifically, L8020 yogurt has

manager (HN) using the random number table. Shikoku

been shown to decrease the oral carriage of four

Nyugyou, Corp. was responsible for the assignment.

known periodontal pathogens, namely P. gingivalis,

The intervention materials (L8020 yogurt and placebo

P. intermedia, T. forsythia, and Fusobacterium spp.16

yogurt) were created, surveyed, individually packed in

Although mechanical removal of plaque biofilm

a quantity of 80 g (as is the commonly used amountspirochetes such as Treponema denticola.

14

J Appl Oral Sci.

2/9

2019;27:e20180564

ODA Y, FURUTANI C, MIZOTA Y, WAKITA A, MIMURA S, KIHARA T, OHARA M, OKADA Y, OKADA M, NIKAWA H

for yogurt in Japan) and delivered under the control of

AIDS. Patients who showed extremely uncooperative

Shikoku Nyugyou, Corp. The dentists and research staff

attitudes toward periodontal examinations were also

at the trial site were blinded to the yogurt preparation

excluded. Individuals who had received antibiotics forused during the study procedures.

the last 3 months and those who already consumed
yogurt on a daily basis were also excluded. None of

Study participants

the patients had active caries, smoked, or were on

The 23 study participants (17 men, six women) had

medication. The study protocol was approved by thesevere ID (intelligence quotient, 35–50). Their mean

Ethical Committee of the University (Epidemiology-No.

age was 33.2 (range, 20–45) years, and the mean

E-342), and the study was registered in the University

periodontal pocket depth was <6 mm. All patients had

Hospital Medical Information Network Center (UMIN)

permanent dentition and visited a Hospital in the city ofunder ID 000023503. Consent for participation was

Hiroshima. For inclusion criteria, patients had finishedobtained from at least one guardian for each patient

active treatment for dental disease and visited theafter explanation of the purpose and contents of thisclinic for regular check-ups involving oral examinations.

study, in accordance with the ethical guidelines of

All patients in this study had regular check-ups forthe Declaration of Helsinki (1975). At the same time,

10.00±5.31 (range, 1–19) years and had received

participants were told that they could withdraw theirperiodontal examination. As for the exclusion criteria,

consent at given moment for any reason.

their hospital records for 2015–2017 were reviewed toconfirm the absence of conditions that can influence theBacterial strains in the trial yogurt preparations

occurrence of periodontal disease, such as diabetes,

L8020 yogurt was prepared by the addition of

autoimmune diseases and infectious diseases like

Streptococcus thermophilus to a large amount of frozen
stock culture of L. rhamnosus L8020. L. bulgaricus andS. thermophilus, which are widely used in fermented
milk products in Japan, were used for preparation of
the placebo yogurt. Standard methods were used forfermentation of the test and placebo samples.16 The
L8020 yogurt contained approximately 1.5×109 lactic
acid bacteria, with 2.0×107 L8020 cells per gram. The
placebo yogurt contained approximately 1.5×109 lactic
acid bacteria. The final pH values for the L8020 yogurt
and placebo yogurt were 4.35 and 4.37, respectively.

Measurements
Dental examinations and periodontal examinations
were performed by a single dentist in the Special Care
Dental Clinic, under artificial lighting with the patientsupine in a dental chair. The PMA index is assigned
to each gingival unit of the maxillary and mandibular
anterior teeth as follows: 0, no inflammation and
1, inflammation. The total PMA index score wascalculated for each patient accordingly. This index
evaluates the number of gingival units (papillary,marginal, and attached gingiva) exhibiting gingival
inflammation around erupted teeth and is limited tothe anterior gingiva. It is assessed by observation

Figure 1- Study flowchart. Individuals with intellectual
disability were allocated to receive L8020 yogurt (bovine milkfermented with Lactobacillus rhamnosus L8020; test group) or
a conventionally prepared commercial yogurt (placebo group).
The study parameters were measured before the start of yogurt
consumption (baseline), after 45 and 90 days of continuous
daily yogurt consumption, and 30 days after cessation of yogurt
consumption

J Appl Oral Sci.

without the use of a prescribed instrument. We also
calculated the GI score for all patients on the basis of
the following scoring system: 0, no inflammation; 1,
mild inflammation; 2, moderate inflammation; and 3,
severe inflammation. This was assessed using a mouth

3/9

2019;27:e20180564

Effect of bovine milk fermented with Lactobacillus rhamnosus L8020 on periodontal disease in individuals with intellectual disability: a randomized clinical trial

Statistical analysis

mirror and a calibrated periodontal probe (UNC-15,
Hu-Friedy, Mfg. Co., LLC, Chicago, IL, USA). PD was

The data were analyzed using the full analysis set.

measured from the gingival margin to the bottom ofContinuous variables that were normally distributed

the periodontal pocket using a mouth mirror and aare expressed as means and standard errors, whilecalibrated periodontal probe (UNC-15, Hu-Friedy, Mfg.

those with non-normal distribution are expressedCo., LLC, Chicago, IL, USA). For each patient, GI andas medians and interquartile ranges. Categorical

PD were measured at the mesiobuccal, distobuccal,

variables are expressed as numbers and percentages.

mesiolingual and distolingual aspects of the maxillary

The baseline characteristics of the two groups wereright first molar, maxillary right lateral incisor, maxillarycompared using Student’s t-test (for continuous

left first premolar, mandibular right first premolar,

variables with normal distribution), Mann–Whitney U

mandibular left lateral incisor, and mandibular left firsttest (for variables with non-normal distribution), or

molar. The mean GI score and PD were calculated from

Fisher’s exact test (for nominal variables). The mixed

the values for these 24 points.

effect model repeated measurement (MMRM)22,23 hasbeen extensively used for the analysis of data for

Intraexaminer reliability

continuous endpoints in longitudinal clinical trials. We

Ten patients who were not participants in thisalso used MMRM, with patients as a random factor

study, each of whom had two contralateral teeth(compound symmetry correlation structure) and timewith a PD of >6 mm, were used for assessment ofand group (including the interaction factor) as a fixed

reproducibility. The examiner evaluated these patientsfactor in order to determine the longitudinal effecton three occasions separated by a 3-day interval. The

of continuous consumption of L8020 yogurt on the

reproducibility of PD measurements was sufficiently

PMA index, GI, and PD. All statistical analyses werehigh (grand mean: 2.2, change in mean: 0.07, typicalperformed using JMP Pro 12 (SAS Institute Japan Inc,error: 0.30, repeatability coefficient: 0.84, andTokyo, Japan). A P-value of <0.05 was consideredintraclass correlation coefficient: 0.63). This evaluation

statistically significant.

procedure was periodically repeated during the study.

Table 1- Baseline demographic and dental characteristics of individuals with intellectual disability
Placebo groupn

Test group11

p-value

12-

Sex, n (%)

0.999†
Male

8

-72.7

9

-75

Female

3

-27.3

3

-25

6.3

33.4

Age, years (mean ± SD)

32.9

±

±

4.5

0.825‡Disability, n (%)
Mental retardation

11

-100

12

-100

>0.999†Autistic spectrum disorder

4

-36.4

6

-50

0.680†

Down syndrome

0

0

0

0

>0.999†Cerebral palsy

1

-9.1

0

0

0.478†

Epilepsy

1

-9.1

3

-25

0.590†

28(25, 28)

7.9

9.6

±

Number of teeth, median (IQR)

28(26, 28)

DMFT

9.2

±

Baseline PMA index

21.5

±

8.6

24.8

Baseline GI

1.59

±

0.31

1.55

Baseline PD

2.61

±

0.39

2.9

0.880§
6.5

0.895‡±

6.9

0.336‡±

0.24

0.761‡±

0.66

0.220‡

Placebo group: Patients consumed placebo yogurt for 90 days
Test group: Patients consumed bovine milk fermented with Lactobacillus rhamnosus L8020 (L8020 yogurt) for 90 days
†Fisher’s exact test, ‡unpaired t-test, §Mann–Whitney U test
Values are expressed as means and standard deviations unless otherwise stated.
DMFT: decayed, missing, and filled teeth; GI: gingival index; SD: standard deviation; IQR: interquartile range; PD: probing depth; PMA:
papillary-marginal-attachedJ Appl Oral Sci.

4/9

2019;27:e20180564

ODA Y, FURUTANI C, MIZOTA Y, WAKITA A, MIMURA S, KIHARA T, OHARA M, OKADA Y, OKADA M, NIKAWA H

Results

breakfast every day. Twenty-three patients completed
the study after randomization to the test (n=12)
and placebo (n=11) groups and were consequently

Written informed consent was obtained for 24

included in our analysis (Figure 1). There were nopatients before randomization. Consent was withdrawn

significant differences in the baseline characteristics

for one patient who was not accustomed to eating

Data are expressed as means ± standard errors of the mean*p<0.05, **p<0.01 vs. time 0; †p<0.05, ‡p<0.01 vs. placebo
Figure 2- Mean values and magnitude of change in each clinical parameter for individuals with intellectual disability who consumed
L8020 yogurt (bovine milk fermented with Lactobacillus rhamnosus L8020; test group) or a conventionally prepared commercial yogurt(placebo group). (A) Mean PMA index scores at baseline, after 45 and 90 days of continuous daily yogurt consumption, and 30 days after
the cessation of yogurt consumption (120 days after the start of consumption); (B) The magnitude of change in the PMA index score frombaseline to 90 days and from baseline to 120 days is significantly greater in the test group than in the placebo group (p = 0.006); (C) Mean
GI scores at baseline, after 45 and 90 days of continuous daily yogurt consumption, and 30 days after cessation of yogurt consumption;(D) Magnitude of change in the GI score from baseline to 90 days and from baseline to 120 days; (E) Mean PD values at baseline, after
45 and 90 days of continuous daily yogurt consumption, and 30 days after cessation of yogurt consumption; (F) The magnitude of change
in PD from baseline to 90 days and from baseline to 120 days. GI, gingival index; PD, probing depth; PMA, papillary-marginal-attachedJ Appl Oral Sci.

5/9

2019;27:e20180564

Effect of bovine milk fermented with Lactobacillus rhamnosus L8020 on periodontal disease in individuals with intellectual disability: a randomized clinical trialof patients between the two groups (Table 1).

for 90 days, there was no significant difference in

The mean (standard error) PMA index score in the

PD values between both groups (time*group factor:

test group decreased significantly, from 24.8 (2.0)

p=0.428), although the mean decrease at 45, 90, andat baseline to 18.1 (2.0) after 45 days of yogurt

120 days tended to be greater in the test group thanconsumption, 13.2 (2.0) after 90 days of consumption,in the placebo group [−0.21 (0.07) vs. −0.07 (0.08),

and 13.9 (2.0) at 30 days after the cessation of

p=0.189; −0.42 (0.07) vs. −0.27 (0.08), p=0.167;

consumption (p<0.001 vs. baseline for all). The

and −0.28 (0.07) vs. −0.14 (0.08), p=0.174,

corresponding values in the placebo group were 21.5

respectively; Figure 2F].

(2.1), 18.3 (2.1) (p=0.177), 16.2 (2.1) (p=0.007),
and 17.5 (2.1) (p=0.057), respectively. Thus, there
was no significant difference between the baseline

Discussion

value and the value at 30 days after cessation of
consumption (Figure 2A). After yogurt consumption

In this study, we found that regular consumption

for 90 days, there was a significant difference in theof bovine milk fermented with L. rhamnosus L8020

PMA index score between the two groups (time*group(L8020 yogurt) can lower the risk of periodontal

factor: p=0.022). The mean decreases in the PMA

disease in individuals with ID.

index score from baseline to 90 days and from baseline

The number of individuals with ID is increasing

to 120 days were significantly greater in the testworldwide, including Japan, because of populationgroup than in the placebo group [−11.6 (1.6) vs. −5.4

growth, increased reporting and more accurate(1.7), p=0.010; −10.8 (1.6) vs. −4.1 (1.6), p=0.006,

methods for detection and diagnosis.24 The Summary

respectively; Figure 2B].

of the Annual Report on Governmental Measures for

The mean GI score for the test group showed

Persons with Disabilities published by the Cabinet

a significant decrease from 1.55 (0.11) at baseline

Office of Japan in 2016 reported that the population

to 1.22 (0.11) after 45 days of consumption, 0.87

with ID in Japan doubled from 297,100 in 1995 to(0.11) after 90 days of consumption, and 1.05 (0.11)

622,000 in 2011.25 Many ID-related characteristics may

at 120 days after the start of consumption (p<0.001

increase the risk of periodontal disease;26 therefore,vs. baseline for all). The placebo group also showed

individuals with ID may have worse oral hygiene anda significant decrease in the mean GI score, from

more oral disease than do healthy individuals.2-4 The

1.59 (0.12) at baseline to 1.33 (0.12) at 45 days

ID population is very heterogeneous, ranging from

(p=0.006), 1.13 (0.12) at 90 days (p<0.001), andindividuals with mild ID, who should be fully integrated

1.17 (0.12) at 120 days (p<0.001; Figure 2C).

into the general population in every aspect, to those

After yogurt consumption for 90 days, there was nowith severe ID, who need full-time care. Therefore,

significant difference in the GI score between thethe specific oral health care needs of the subgroups in

two groups (time*group factor, p=0.255). However,this population require clear definition.5 Ozgul, et al.27

the mean decrease in the score from baseline to 90(2014) reported a significant positive correlation ofdays tended to be greater in the test group than in

the severity of ID with clinical periodontal indices andthe placebo group [−0.68 (0.08) vs. −0.46 (0.08);

the number of missing teeth. Clearly, toothbrushing

p=0.050; Figure 2D].

is the most effective way of preventing periodontal

The mean PD in the test group showed a significant

disease. However, our study sample was limited todecrease from 2.90 (0.14) mm at baseline to 2.68

patients with severe ID, for whom toothbrushing and(0.14) mm at 45 days (p=0.015), 2.48 (0.14) mm atoral cleaning by caregivers may be impossible due to

90 days (p<0.001), and 2.62 (0.14) mm at 120 days

noncompliance. Thus, other measures for preventing(p<0.001). In the placebo group, the mean PDs atperiodontal disease that are easily accepted bybaseline and 45 and 90 days were 2.61 (0.15), 2.53

individuals with severe ID would be beneficial.

(0.15) (p=0.999), and 2.33 (0.15) mm (p=0.002),

Although our patient sample comprised individuals

respectively. Thereafter, mean PD increased to 2.47

with ID, it should be noted that even elderly individuals(0.15) mm at 120 days (p=0.234), and there was

who need full-time care cannot brush their teeth onno significant difference from the baseline depth attheir own. Therefore, L8020 yogurt consumption may

this time point (Figure 2E). After yogurt consumption

J Appl Oral Sci.

be a useful strategy for the maintenance of oral health

6/92019;27:e20180564

ODA Y, FURUTANI C, MIZOTA Y, WAKITA A, MIMURA S, KIHARA T, OHARA M, OKADA Y, OKADA M, NIKAWA H

in elderly individuals as well. Future studies should

which probiotics exert their clinical effects on the

explore the effect of L8020 yogurt consumption on

periodontal gingiva.

periodontal diseases in the elderly.

In our study, there was a decrease in PD after

In Japan, there are records of 31.90 million

90 days of continuous yogurt consumption in bothindividuals aged ≥65 years. The proportion ofexperimental groups. We speculate that there may be

individuals in this age group increased from 24.1%

two explanations for the decrease in PD in the patientsin 2012 to 25.1% in 2013, and a certain projection

who consumed the placebo yogurt that did not containstates that one in 2.5 individuals and one in four

L. rhamnosus L8020. First, all study participants wereindividuals will be aged ≥65 years and ≥75 years

instructed to refrain from toothbrushing or consuming

by 2060.28 In the future, as the overall population of

any food or beverage for 1 h after consumption

Japan decreases, the proportion of elderly individualsof the allocated yogurt in order to maximize therequiring assistance with activities of daily living,amount of time for which the probiotic bacteria in the

including toothbrushing, will continue to increase, so

L8020 yogurt remained in the oral cavity. Also, thean effective strategy for the prevention of periodontal

participants’ guardians or caregivers were instructeddisease in this population would be welcomed.

to brush their teeth at a specific time in the morning

Evidence supporting the health benefits of probiotics

before yogurt consumption, so daily toothbrushingis steadily accumulating, and new therapeutic horizons,

was performed for all participants in both study

particularly those related to Lactobacillus spp. andgroups, including those who were not accustomed

Bifidobacteria, are emerging in the field of periodontal

to it. Second, Lactobacillus strains are commonly

Recent studies have demonstrated theused probiotics,16 and it is possible that Lactobacillus

effectiveness of probiotics containing Lactobacillus spp.

spp. contained in the placebo yogurt also influenced

disease.

29

however,

periodontal bacteria. Further research using next-

there is limited research on the clinical benefits of L.

generation sequencing is necessary to elucidate therhamnosus L8020 (L8020 yogurt). Although Nikawa,changes that occur in the oral microbiota in response to

et al. (2011) reported that L8020 yogurt reduced thecontinuous consumption of yogurt containing different

carriage of P. gingivalis, P. intermedia, T. forsythia,

types of probiotics.

in the prevention of periodontal disease;

29,30

16

and Fusobacterium spp. in vitro, it remained unclear

This study has some potential limitations,

whether clinical benefits would be seen in patients as

including the limited observation period of 120 days,

well. In our study, the magnitude of change in thethe relatively short yogurt consumption period ofmean PMA score from baseline to 90 and 120 days

90 days, and the small sample size. As this study

after the start of daily L8020 yogurt consumption

was a preliminary rather than a confirmation study

was significantly greater in the test group than ininvestigating the clinical effect of L8020 yogurt, there

the placebo group. Furthermore, the magnitude of

was no previous information with which to determinechange in the GI score and PD from baseline to 90

an adequate sample size. On the basis of a similardays tended to be greater in the test group than inprevious study,29 we calculated that 15 individuals withthe placebo group, suggesting that L8020 yogurt has

ID who were otherwise healthy would be required toa beneficial effect on periodontal disease in patientsensure an adequate sample size. However, our trial

with ID. Although changes in all three parameters

was performed on patients with severe ID, and weshowed a decreasing trend, only the change in thewere thus limited in the recruitment of participants

PMA index score decreased significantly after 90 days

who met the study criteria. In particular, among theof consumption of L8020 yogurt. PMA differs from the1109 outpatients who regularly visit our office inother two parameters in that it reflects inflammation

the Hiroshima area, it was extremely difficult to findof the papillary, marginal, and attached gingiva, rather

individuals with severe ID who were available forthan reflecting only inflammation of the periodontal

irregular visits and repeated dental examinations.

pockets. Thus, it is possible that a decrease inHence, we decided that the final sample size wasperiodontal pathogens affects inflammation of thewithin the realistic and feasible range. Though we

papillary, marginal, and attached gingiva earlier thanwere unable to fulfill the initial goal of 15 subjects,

that of the periodontal pockets. However, further

in retrospect, the amount of change in PMA after theinvestigation is needed to determine the order instart of intervention was -10.8±5.6 (mean±SD) in the

J Appl Oral Sci.

7/9

2019;27:e20180564

Effect of bovine milk fermented with Lactobacillus rhamnosus L8020 on periodontal disease in individuals with intellectual disability: a randomized clinical trial

Acknowledgments

test group and -4.1±5.3 in the placebo group, meaningthat our sample size was appropriate for determining

This study did not receive any specific grant fromdifferences between the two groups with a power offunding agencies in the public, commercial, or not-80.2%. The preliminary results presented here remain

for-profit sectors.

to be confirmed in additional subjects in a future study.

Conflict of interest

Although probiotics in the microbiota of the humanoral cavity, if compatible with the ecosystem, are likely

The authors declare no conflict of interest.

to be effective in preventing periodontal disease,29
the minimum duration of consumption before thedevelopment of changes in the oral microbiota remains

References

unclear. The difference in PD between baseline and 45days and between baseline and 90 days in our test

1- Solanki J, Khetan J, Gupta S, Tomar D, Singh M. Oral rehabilitation andgroup indicates that PD decreases with an increase

management of mentally retarded. J Clin Diagn Res. 2015;9(1):ZE01-6.
2- Anders PL, Davis EL. Oral health of patients with intellectualin the duration of yogurt consumption; however, itdisabilities: a systematic review. Spec Care Dentist. 2010;30(3):110-7.

remains unknown whether long-term consumption

3- Glassman P, Miller CE. Preventing dental disease for people withof L8020 yogurt has additional benefits or a ceiling

special needs: the need for practical preventive protocols for use incommunity settings. Spec Care Dentist. 2003;23(5):165-7.

effect. Therefore, toothbrushing remains the most

4- Meurs D, Rutten M, de Jongh A. Does information about patients

important preventive and therapeutic strategy for

who are intellectually disabled translate into better cooperation during
dental visits? Spec Care Dentist. 2010;30(5):200-5.

periodontal disease, and probiotics should only be used

5- Petrovic BB, Peric TO, Markovic DL, Bajkin BB, Petrovic D, Blagojevic

as a supplementary measure. Patients, parents, andDB, et al. Unmet oral health needs among persons with intellectual

caregivers should be warned that the consumption of

disability. Res Dev Disabil. 2016;59:370-7.
6- Chang J, Lee JH, Son HH, Kim HY. Caries risk profile of Korean

L8020 yogurt alone cannot replace toothbrushing as

dental patients with severe intellectual disabilities. Spec Care Dentist.

a measure for the maintenance of oral health.

2014;34(4):201-7.
7- Oda Y, Hayashi F, Wakita A, Nagatani Y, Okada M. Five-year
longitudinal study of dental caries risk associated with Streptococcus
mutans and Streptococcus sobrinus in individuals with intellectual

Conclusions

disabilities. J Oral Sci. 2017;59(1):39-46.
8- Oda Y, Hayashi F, Okada M. Longitudinal study of dental caries
incidence associated with Streptococcus mutans and Streptococcus

In conclusion, the consumption of bovine milk-sobrinus in patients with intellectual disabilities. BMC Oral Health.

derived L. rhamnosus L8020 yogurt for 90 days

2015;15:102.

resulted in significantly greater changes in the PMA

9- Finkelman MD, Stark PC, Tao W, Morgan JP. Relationship between
duration of treatment and oral health in adults with intellectual andindex than the consumption of placebo yogurt for thedevelopmental disabilities. Spec Care Dentist. 2014;34(4):171-5.

same duration; moreover, it tended to decrease GI

10- Brown AC, Valiere A. Probiotics and medical nutrition therapy. Nutr

score and PD. Our findings suggest that L. rhamnosus

Clin Care. 2004;7(2):56-68.
11- Rasic JL. The role of dairy foods containing bifido- and acidophilus

L8020 may be a useful probiotic organism whenbacteria in nutrition and health. N Eur Dairy. 1983;4:80-8.

included in products that are ingested daily. However,12- Krasse P, Carlsson B, Dahl C, Paulsson A, Nilsson A, Sinkiewicz
G. Decreased gum bleeding and reduced gingivitis by the probiotic

further investigation is needed to elucidate the effect ofLactobacillus reuteri. Swed Dent J. 2006;30(2):55-60.

L. rhamnosus L8020 on the oral microbiota and clarify

13- Mayanagi G, Kimura M, Nakaya S, Hirata H, Sakamoto M, Benno

the limits of the effects of this probiotic organism on

Y, et al. Probiotic effects of orally administered Lactobacillus salivarius
WB21-containing tablets on periodontopathic bacteria: a double-

periodontal disease.

blinded, placebo-controlled, randomized clinical trial. J Clin Periodontol.
2009;36(6):506-13.

Ethical approval

14- Kamma JJ, Nakou M, Gmür R, Baehni PC. Microbiological profile of

The study protocol was approved by the Ethicalearly onset/aggressive periodontitis patients. Oral Microbiol Immunol.
2004;19(5):314-21.

Committee of Hiroshima University (Epidemiology-

15- Nikawa H, Makihira S, Fukushima H, Nishimura H, Ozaki Y, Ishida

No. E-342), and the study has been registeredK, et al. Lactobacillus reuteri in bovine milk fermented decreases

in the University Hospital Medical Information

the oral carriage of mutans streptococci. Int J Food Microbiol.

Network (UMIN) Center (ID 000023503). Consent

2004;95(2):219-23.
16- Nikawa H, Tomiyama Y, Hiramatsu M, Yushita K, Takamoto Y, Ishi

for participation was obtained from at least one

H, et al. Bovine milk fermented with Lactobacillus rhamnosus L8020

guardian of each patient in accordance with the ethicaldecreases the oral carriage of mutans streptococci and the burden of

guidelines of the Declaration of Helsinki (1975).

periodontal pathogens. J Investig Clin Dent. 2011;2(3):187-96.

J Appl Oral Sci.

8/9

2019;27:e20180564

ODA Y, FURUTANI C, MIZOTA Y, WAKITA A, MIMURA S, KIHARA T, OHARA M, OKADA Y, OKADA M, NIKAWA H

17- Ahad A, Lamba AK, Faraz F, Tandon S, Chawla K, Yadav N. Effect

25- Japan. Cabinet Office. Annual Report on Government Measuresof antimicrobial photodynamic therapy as an adjunct to nonsurgicalfor Persons with Disabilities (Summary): 2016 [internet]. 2016. [Cited

treatment of deep periodontal pockets: a clinical study. J Lasers Med

2018 October 10]. Available from: http://www8.cao.go.jp/shougai/

Sci. 2016;7(4):220-6.

english/annualreport/2016/index-pdf.html.

18- Anusha RL, Umar D, Basheer B, Baroudi K. The magic of magic bugs

26- Morgan JP, Minihan PM, Stark PC, Finkelman MD, Yantsides KE,

in oral cavity: probiotics. J Adv Pharm Technol Res. 2015;6(2):43-7.

Park A, et al. The oral health status of 4,732 adults with intellectual

19- Pujia AA, Costacurta M, Fortunato L, Merra G, Cascapera S, Calvani

and developmental disabilities. J Am Dent Assoc. 2012;143(8):838-46.

M, et al. The probiotics in dentistry: a narrative review. Eur Rev Med

27- Ozgul O, Dursun E, Ozgul BM, Kartal Y, Coskunses FM, Kocyigit

Pharmacol Sci. 2017;21(6):1405-12.

ID, et al. The impact of handicap severity on oral and periodontal

20- Schour I, Massler M. Survey of gingival disease using the PMA

status of patients with mental retardation. J Contemp Dent Pract.

index. J Dent Res. 1948;27:733-8.

2014;15(2):218-22.

21- Löe H, Silness J. Periodontal disease in pregnancy. I. Prevalence

28- Japan. Cabinet Office. Annual Report on Aging Society: 2016

and severity. Acta Odontol Scand. 1963;21:533-51.

(Summary) [internet]. 2014. [Cited 2018 October 10]. Available http://

22- Tang Y. On the multiple imputation variance estimator for control-

www8.cao.go.jp/kourei/english/annualreport/2014/2014pdf_e.html.

based and delta-adjusted pattern mixture models. Biometrics.

29- Sajedinejad N, Paknejad M, Houshmand B, Sharafi H, Jelodar

2017;73(4):1379-87.

R, Shahbani Zahiri H, et al. Lactobacillus salivarius NK02: a potent

23- Traeger AC, Skinner IW, Hübscher M, Lee H, Moseley GL, Nicholas

probiotic for clinical application in mouthwash. Probiotics Antimicrob

MK, et al. A randomized, placebo-controlled trial of patient education

Proteins. 2018;10(3):485-95.

for acute low back pain (PREVENT Trial): statistical analysis plan. Braz

30- Montero E, Iniesta M, Rodrigo M, Marín MJ, Figuero E, Herrera D, et

J Phys Ther. 2017;21(3):219-23.

al. Clinical and microbiological effects of the adjunctive use of probiotics

24- Nunn JH, Murray JJ. The dental health of handicapped children inin the treatment of gingivitis: a randomized controlled clinical trial. J

Newcastle and Northumberland. Br Dent J. 1987;162(7):251.

Clin Periodontol. 2017;44(7):708-16.

J Appl Oral Sci.

9/9

2019;27:e20180564