The prevalence of dental caries in VS children were high
101 VS children, including 69 boys and 32 girls, with an age range of 6 to 16 years and a mean age of 10.13 ± 2.09 years were included in this study. All 101 VS children had a total caries rate of 92.1%, which included a caries filling rate of 16.8%, a primary tooth caries rate of 60.4%, and a permanent tooth caries rate of 76.24%. The prevalence and severity of dental caries in the participating students are summarised in Table 1. According to Fisher's exact probability analysis, there was no discernible difference between the caries and caries filling rates of boys and girls (P > 0.05).
Table 1
The status of dental caries in visually impaired students
Sex
|
dt/DT
[M(P25,P75)]
|
dmft
[M(P25,P75)]
|
DMFT
[M(P25,P75)]
|
dmft/DMFT
[M(P25,P75)]
|
Caries
prevalence
rate (%)
|
Caries filling rate (%)
|
Male
|
4 (2, 8)
|
1.3 (0, 6)
|
3.03 (1, 4)
|
4.8 (3, 8.5)
|
94.2
|
17.4
|
Female
|
4.5 (3, 6.8)
|
2.2 (0, 5)
|
3.07 (0, 4)
|
5.6 (3.3, 8.8)
|
87.5
|
15.6
|
Caries activity was associated with the degree of caries
A total of 101 samples were collected for the purpose of conducting caries activity testing in an efficient manner. In the study, the caries activity score of male participants was recorded as 1.5, while the caries activity score of female participants was also observed to be 1.5. The Mann-Whitney test revealed no statistically significant difference in caries activity grade between sexes (Z = -0.73, P > 0.05, Table 2). Based on the number of dental caries, children with VS were divided into three groups: low caries (3.16 ± 1.7), mid-caries (4.68 ± 3.51), and high caries (8.1 ± 3.97). According to the Kruskal-Wallis test, there is a statistically significant positive correlation between caries severity and caries activity (Z = 18.73, P < 0.05, Table 3).
Table 2
the results of caries activity in children with visual impairment
Sex
|
Caries activity test score
|
< 1
|
1-1.5
|
≥ 2
|
Male
|
3(4.3%)
|
44(63.8%)
|
22(31.9%)
|
Female
|
3(9.4%)
|
15(46.9%)
|
14(43.8%)
|
Note:Low-caries: Caries activity test score < 1; Mid-caries: Caries activity test score 1-1.5; |
High-caries: Caries activity test score ≥ 2.
Table 3
The relationship between caries risk and caries severity
Caries risk
|
N
|
dmft/DMFT[M(P25,P75)]
|
Low-caries
|
6
|
3.5 (1.5, 5)
|
Mid-caries
|
59
|
4.07 (2, 7)
|
High-caries
|
36
|
7.67 (5.25, 11.75)
|
Note:Low-caries: Caries activity test score < 1;Mid-caries: Caries activity test score 1-1.5;
High-caries: Caries activity test score ≥ 2.
Deficient oral hygiene among the children of VS
A compilation of 101 questionnaires was undertaken, of which 94 were deemed valid and 7 were deemed invalid, for a mean effectiveness rate of 93.07%. A total of 49 out of 94 children, or nearly 52.1%, brushed their teeth daily. 84% (79/94) of children independently brushed their teeth. 13.8% (13 out of 94) of children initiated brushing hygiene following the two-year mark. Children who brushed their teeth at least twice daily comprised 52.1% (49/94). 61.7% (58 out of 94) of children brushed their teeth morning and nightly. 39.4% (37/94) of children used fluoride-containing toothpaste. 45.7% (43/94) of them consumed a dessert or beverage prior to bedtime; this difference was statistically significant between the sexes (P < 0.05) (Table 4).
Caries activity was further analysed in light of the influencing factors, which are presented in the Table 4. Children with VS who independently brushed their teeth had a higher caries activity score than those who required assistance in whole or in part (P > 0.05). The three caries activity groups had no statistically significant differences in oral hygiene practises (P > 0.05).
Table 4
The oral hygiene habits of visually impaired children of different genders (n = 94)
|
Male
|
Female
|
Total
|
P value
|
The number of subjects
|
Total
|
H cost
|
P value
|
Low caries
|
Mid caries
|
High caries
|
Do child brush their teeth?
|
|
|
|
0.48
|
|
|
|
|
0.22
|
0.63
|
Brush teeth
|
63
|
29
|
92
|
6
|
53
|
33
|
92
|
|
|
Brush infrequently or never brush
|
2
|
0
|
2
|
0
|
2
|
0
|
2
|
|
|
The degree of independence in brushing
|
|
|
|
0.25
|
|
|
|
|
0
|
1
|
Independent
|
54
|
25
|
79
|
5
|
46
|
28
|
79
|
|
|
Partially dependent
|
11
|
3
|
14
|
1
|
8
|
5
|
14
|
|
|
Completely dependent
|
0
|
1
|
1
|
0
|
1
|
0
|
1
|
|
|
The frequency of tooth brushing
|
|
|
|
0.57
|
|
|
|
|
0.31
|
0.58
|
Twice daily
|
31
|
18
|
49
|
4
|
29
|
16
|
49
|
|
|
Once daily
|
31
|
11
|
42
|
2
|
24
|
16
|
42
|
|
|
It's not every day
|
1
|
0
|
1
|
0
|
0
|
1
|
1
|
|
|
The time has come for the child to brush his teeth
|
|
|
|
0.23
|
|
|
|
|
1.23
|
0.27
|
Typically, once in the morning or before going to bed at night
|
27
|
9
|
36
|
1
|
22
|
13
|
36
|
|
|
Every day in the morning and evening
|
38
|
20
|
58
|
5
|
33
|
20
|
58
|
|
|
Should you use fluoride toothpaste when you brush your teeth?
|
|
|
|
0.06
|
|
|
|
|
2.09
|
0.15
|
Yes
|
21
|
16
|
37
|
3
|
21
|
13
|
37
|
|
|
Deny
|
10
|
4
|
14
|
2
|
9
|
3
|
14
|
|
|
Nothing about
|
31
|
7
|
38
|
|
0
|
22
|
16
|
38
|
|
|
Have a dessert or a drink before bed
|
|
|
|
< 0.01
|
|
|
|
|
0.22
|
0.64
|
Often
|
1
|
0
|
1
|
0
|
0
|
1
|
1
|
|
|
Every now and then
|
35
|
7
|
42
|
3
|
22
|
17
|
42
|
|
|
Never
|
29
|
22
|
51
|
3
|
33
|
15
|
51
|
|
|
Table 5
Number of species annotations in each of the two taxonomic groups
Groups
|
Phylum
|
Class
|
Order
|
Family
|
Genus
|
Species
|
HS
|
16
|
24
|
42
|
73
|
132
|
173
|
VS
|
17
|
26
|
48
|
80
|
143
|
183
|
Sample characteristics and data output
Twenty saliva samples, nine girls and eleven boys, between the ages of 7 and 12, were taken from HS students. With 5 children having no caries, 11 having moderate caries, and 4 having high caries, the mean dmft/DMFT was 3.15. Twenty children with VS, three girls and seventeen boys, between the ages of seven and twelve, had their saliva samples taken. With two children having no caries, eight having moderate caries, and ten having high caries, the the mean dmft/DMFT was 6.75. High-throughput sequencing analysis of 16S rRNA revealed that 40 saliva samples yielded 3,199,305 raw sequences (Raw Reads) and 3,189,730 high-quality series (Clean Reads) (Fig. 1A). 10,133 OTUs were produced by OTU clustering of high-quality sequences in each sample based on 97% similarity. Of these, 5,119 OTUs were found in HS groups and 5,014 OTUs in VS groups. Once they rose within a specific range, the rarefaction curves plateaued (Fig. 1B), showing that the amount of samples sequenced was adequate to reflect the diversity of the microbial community and sufficient for the upcoming data analysis. As shown in Fig. 1C, the HS group had a greater diversity and uniformity of microbial species than the VS group.
Comparable salive microbiota in VS and HS children
Regarding the abundance-based coverage estimator (ACE) index (Fig. 2A) and Chao1 index (Fig. 2B), the number of species in the VS group was higher than that in the HS group (P > 0.05), illustrating that the baseline microbial abundance was consistent. Based on the Shannon index (Fig. 2C) and Simpson index (Fig. 2D), no signifcant diference in microbial species diversity among all groups was observed .
To determine whether there were significant differences in the diversity of beta between samples, further analysis of similarities was conducted (ANOSIM; Fig. 3A); the findings showed that there were none, either between or within groups. The data points in the HS and VS groups were concentrated. NMDS analysis illustrated that the saliva samples from HS an VS had no significant difference (Fig. 3B). Unweighted Pair Group Method with Arithmetic Mean analysis (UPGMA; Fig. 3C) demonstrated that the microbial community composition was similar between the HS and VS groups. Based on the concentration of the majority of data points between the two groups, there was no statistically significant distinction observed in the composition of the salivary microbial community between the two groups (P > 0.05).
No signifcant diferences in the distribution of predominant microorganisms between two groups
According to the clustering and annotation of OTU statistics, the salivary microbial communities obtained in this study contained 17 phyla, 26 classes, 48 orders, 80 families, 143 genera, and 183 species (Table 5). At the phylum level (Figs. 4A,D), the top 10 dominant phyla in terms of relative abundance were Firmicutes (45.4%), Actinobacteria (21.6%), Bacteroidetes (11.5%), Proteobacteria (10.1%), Fusobacterium (5.6%), Patescibacteria (3.9%), Spiroplasma (0.6%), Epsilonbacteraeota (0.17%), Verrucomicrobia (0.04%), and Tenericutes (0.04%). Regarding Firmicutes, the VS group (37.8%) had the lower abundance (P = 0.27). Regarding Actinobacteria, Bacteroidetes, Proteobacteria and Firmicutes, the VS group had the higher abundance, but the difference was not statistically significant (P > 0.05).
At the level of the class (Figs. 4B,E), a total of 26 classes were found in the two groups of salivary microbial communities. The top 10 dominant bacteria in relative abundance were Bacilli (32%), Actinobacteria (20.7%), Bacteroidua (11.5%), Gammaproteobacteria ( 10.7%), Negativicutes (8.1%), Fusobacteria (5.4%), Clostridia (4.5%), Saccharimonadia (3.2%), Coriobacteriia (0.89%), and Erysipelotrichia (0.59%). The abundance of Bacilli and Negativicutes was lower in the VS group, while the abundance of Actinobacteria, Bacteroidia, and Gammaproteo bacteria were higher in the VS group, but the diference was not statistically signifcant (P > 0.05).
At the level of the genus (Figs. 4C,F), a total of 143 genera were identified in the salivary microbial communities of the two groups. The top 10 dominant bacteria in relative abundance were Streptococcus (22.93%), Rothia (15.56%), Neisseria (6.27%), Veillonella (6.21%), Prevotella_7 (3.57%), Actinomyces (4.13%), Leptotrichia (3.99%), unclassified Lactobacillales (3.26%), Porphyromonas (3.52%), and Gemella (3.07%). The abundance of Streptococcus, Porphyromonas and Gemella was the lower in the VS group, while the abundance of Rothia, Neisseria, Veillonella and Prevotella_7 was higher in the VS group, but the diference was not statistically signifcant (P > 0.05).
At the level of the genus (Fig. 5A), the enrichment of Rothia, Neisseria, Prevotella_7, Haemophilus, Fusobacterium and Actinomyces was significantly greater in VS children with caries (VSC) than in HS children with caries (HSC). At the level of the genus (Fig. 5B), Individuals with severe caries (VSCS) have a higher presence of microbiota such as Rothia, Streptococcus, Prevotella_7, Actinomyces and Gemella in the VS population, whereas those with mild to moderate caries (VSCM) have a higher presence of microbiota such as Porphyromonas and Fusobacteriia.
Biomarkers of salive microbiota among groups
LEfSe (LDA Effect Size) analysis reflects the differences in core microbial distribution between groups, namely species analysis with significant differences between groups, and selects the microorganisms with significant differences in abundance between groups. As shown in Fig. 6, through comparative analysis for the microorganisms with significant differences and with linear discriminant analysis (LDA) scores above 4.0 based on linear discriminant analysis effect size (LEfSe) analysis, the taxonomic biomarkers in Group VS was Actinobacteria. The taxonomic biomarkers in Group HS were Firmicutes, Bacilli, Lactobacillales, Streptococcaceae and Streptococcus.
Network analysis
Co-occurrence analysis was performed to recognize interactions among phylum in different groups. The top 80 phylum with high relative abundance were found to have complex interactions in each group (Fig. 7). Different groups clearly showed different bacterial correlations, and there were 7 and 5 negative correlations in the HS and VS groups, respectively. In the VS group, Actinobacteria had a positive correlation with Firmicutes and Spirochaetes. In the VS group, Actinobacteria had a negative correlation with Fusobacteria and Tenericutes. Compared to that in the VS group, Actinobacteria in the HS groups only exhibited a negative correlation. VS had simpler correlation networks than HS.