Since dental caries is a multifactorial disease, the occurrence of caries can be predicted through a caries activity test that measures various variables to identify people at high risk of developing caries [1]. Methods of caries activity tests are dental caries test methods that can predict the possibility of caries occurring in a specific person and take appropriate countermeasures, including the Snyder test, salivary secretion test, saliva consistency test, saliva buffering capacity test, and dental crevice bacterial film. There are hydrogen ion concentration tests, dental surface bacterial film regeneration rate tests, oral glucose residence time tests, and oral environment management ability tests [2]. There are three factors that affect the occurrence of dental caries: pathogen factors, environmental factors, and host factors. Pathogen factors include polymorphic streptococcus, acidophilic lactic acid bacteria, and acid. Environmental factors include oral environmental factors such as oral environment, oral temperature, and dental plaque, natural environmental factors such as fluoride ion concentration in drinking water and temperature, and economic level. Includes social and environmental factors [3,4]. Host factors include dental factors such as tooth composition, shape, position, and arrangement, and salivary factors, and are also included in extraoral physical host factors such as race, genetics, age, gender characteristics, developmental disorders, and emotional disorders [5].

Among these, salivary factors include salivary secretion amount, salivary consistency, salivary buffering capacity, and acidity. This saliva is a mixed fluid secreted from various salivary glands open in the oral cavity. Saliva is a secretion secreted from the large salivary glands, such as the parotid, sublingual, and submandibular glands, and the minor salivary glands that open into the oral mucosa when chewing food. It not only induces smooth swallowing, but also lubricates the teeth and oral mucosa to relieve external stimulation. It plays an important role in protecting against damage and damage [3]. In addition, it has a cleaning, lubricating, buffering, and digestive effect by wiping away various foreign substances, suppresses the occurrence of dental caries, contributes to remineralization, and has antibacterial, antifungal, and antiviral effects [2]. The total amount of saliva secreted during the day is about 1-1.5 L, and about half of the total amount is secreted at rest, and the other half is secreted by various stimuli such as eating, and a small amount is also secreted during sleep [2]. This saliva is a major factor affecting the periodontal condition of dental caries and affects the occurrence of oral diseases. Dental caries is a dental disease with the highest morbidity rate and accounts for most of the causes of tooth loss [3]. It is the destruction of hemorrhoids caused by three factors: bacteria as pathogens, teeth and saliva as host factors, and dental plaque and diet as environmental factors. It is a phenomenon [2-6].

Therefore, for efficient management of dental caries, it is necessary to identify and block the mechanisms that cause dental caries. The causes of dental caries include Miller’s [7] chemical bacteria theory, Gottlieb’s [8] protein lysis theory, and Schatz and Martin’s [9] protein lysis chelation theory, but they have not been clearly identified, and Zickert et al. [10] and Krasse [11] believe that Streptococcus Mutans causes dental caries. It was argued that there was a close relationship. The dental caries activity test, which is one of the effective methods to diagnose the risk of dental caries, finds the cause of dental caries caused by various complex factors in the oral cavity, and based on this, takes into account the characteristics of each individual. It is a series of processes aimed at efficiently preventing the occurrence of oral diseases. Even in dental clinical practice, predicting the caries activity of individual patients can be helpful in successful treatment [12]. Recently, factors such as the number of acid-producing bacteria in the oral cavity, acidic components in the dental bacterial film, salivary secretion amount and salivary consistency, lack of salivary buffering capacity, and poor oral hygiene have been listed as specific causes of dental caries [13]. Among the previous studies on factors causing dental caries, studies such as the investigation of salivary secretion rate and pH changes in saliva and clinical comparative study between the Snyder test [14] and Englander’s comparative analysis data of salivary secretion rate and salivary pH change [15]. As a result of comparative analysis of the data, it was possible to find a correlation between the occurrence of dental caries and saliva. Through this study, based on the dental caries activity test results of some adults who participated in the program, the correlation between the dental caries experience of adults and the dental caries activity test was analyzed to provide basic data to reveal the causes of dental caries.

1. Research subject

From September to December 2023, 67 (24.7±1.61) participants of the community center program located in Building S in City A were selected and given an explanation of dental caries and the dental caries activation method used to identify factors causing dental caries. This study was conducted on people who agreed to participate in the experiment. The study was conducted on a total of 67 people, including 38 people in their 20s and 30s, 38 people in their 40s and 50s, and 31 people in their 60s and older, who lived in S-dong in City A and voluntarily participated in the community center program. The dental caries activity test method was used. We attempted to administer this to all program participants, but non-participants who did not visit on the day of the test were excluded (Table 1).

Table 1 . Distribution of research subjects

Item	Total	M	F
Total	67	13	54
20s to 30s	15	4	11
40s to 50s	41	7	34
Over 60s	11	2	9

2. Research method

In order to ensure homogeneity of study subjects, the same experiment time and experiment equipment were used for each dental caries activity test method, and the experiment was conducted at the education room of the community center in S-dong, A-city. The caries activity test method used in this study was conducted as follows based on the latest preventive dental hygiene practice book [16].

Two salivary secretion rate tests were conducted: stimulated salivary secretion rate and non-stimulated salivary secretion rate test. First, the irritant salivary secretion rate test was performed by collecting saliva secreted for 5 minutes while chewing 1.0 g of unflavored paraffin in a 25 ml graduated cylinder, standing it for 1 minute, and observing it. Saliva secreted in a steady state was collected for 5 minutes in a 25 ml graduated cylinder and then measured.

For the saliva consistency test, 2 ml of irritating saliva was measured using a saliva viscometer (Ostwald pipette) to determine the ratio of the time required for 2 ml of distilled water to flow out of the saliva viscometer and the time required for 2 ml of saliva to flow down.

Consistency of saliva = time (seconds) taken for 2 ml of saliva to flow/time (seconds) taken for 2 ml distilled liquor to flow

For the saliva buffering capacity test, the irritating saliva secreted for 5 minutes is collected with a dropper using a saliva test buffer (Saliva-check buffer, GC, JAPAN), the saliva is dropped on each pad, and the completed results are shown below after 2 minutes. Measured by comparing with the color cart.

3. Data analysis

Statistical analysis of the collected data was performed using SPSS (Statistical Package for the Social Sciences) statistical program 18.0 (Spss Inc., SPSS Inc Chicago IL USA). The mean and standard deviation were calculated to determine the level of dental caries experience, and the frequencies and percentages were calculated to find out the details of existing teeth, caries teeth, missing teeth, and filled teeth. To determine the average of the dental caries activity test, the mean and standard deviation were calculated, and an independent sample t-test was performed to determine the relationship between the dental caries activity test method and ongoing dental caries (non-caries and caries), and the caries activity test was performed. Pearson’s correlation analysis was performed to identify the correlation between methods.

1. Experience with dental caries in permanent teeth

The number of teeth with caries was 1.82, the number of teeth extracted due to caries was 2.89, and the number of teeth with fillings was 7.48, and the average number of teeth experiencing permanent tooth caries was 12.19 (Table 2).

Table 2 . Experience level of dental caries

Item	N	M±67SD	Existing teeth number (M±SD)	DMFT index (M±SD)
D	67	1.82±2.84	27.00±2.24	12.19±3.18
M	67	2.89±1.39
F	67	7.48±4.82

D: decayed teeth, M: missing teeth, F: filling teeth.

2. Existing teeth, caries teeth, missing teeth, filled teeth

The subjects’ existing teeth were found to be 26 (52.2%), the proportion of subjects with dental caries was found to be 49.3%, the subjects with filled teeth due to dental caries were found to be 97.01%, and those with missing teeth were found to be 20.9% was found to be (Table 3).

Table 3 . Results of existing teeth, dental caries, missed teeth, and filled teeth existing teeth number

Existing teeth number				Decayed				Missing				Filling
Number	Frequency	%		Number	Frequency	%		Number	Frequency	%		Number	Frequency	%
24	1	1.53		0	34	50.7		0	53	79.1		0	2	2.99
25	4	5.97		1	9	13.4		1	4	5.97		1	4	5.99
26	35	52.2		2	7	10.48		2	7	10.4		2	4	5.99
27	6	8.96		3	2	2.99		4	1	1.51		3	3	4.48
28	5	7.46		4	4	5.99		5	1	1.51		4	9	13.4
29	5	7.46		5	2	2.99		10	1	1.51		5	7	10.4
30	7	10.4		7	1	1.49						6	6	8.96
31	1	1.53		8	4	5.99						7	5	7.46
32	3	4.49		9	1	1.49						8	4	5.99
				10	3	4.48						9	10	14.7
												10	5	7.46
												11	1	1.57
												12	1	1.57
												13	2	2.99
												14	3	4.48
												19	1	1.57
Total	67	100.0			67	100.0			67	100.0			67	100.0

Number: number of tooth, Frequency: the number of subjects.

3. Results according to dental caries activity test method

The average stimulated salivary secretion amount was 12.94±3.92 ml, non-stimulated salivary secretion amount was 3.67±1.74 ml, salivary consistency was 1.57±0.71, and salivary buffering capacity was 8.64±2.56 (Table 4).

Table 4 . Average of dental caries activity test

Method	N	M±SD
SSFR	67	12.94±3.92
NSFR	67	3.67±1.74
SV	67	1.57±0.71
SBC	67	8.64±2.56

SSFR: stimulated salivary flow rate, NSFR: non-stimulated salivary flowrate, SV: salivary viscosity, SBC: salivary buffering capacity.

4. Relationship between on going dental caries and dental caries activity test

The relationship between irritant and non-irritant saliva secretion amount, saliva consistency, saliva buffering, and ongoing dental caries is statistically significant. Although there was no difference, the non-caries group showed a higher rate than the caries group. Although it did not show overall statistical significance, the non-caries group showed a higher rate than the caries group (Table 5).

Table 5 . Relationship between dental caries activity test method and dental caries under progression

Method	Appearance of caries	N	M±SD	t	p
SSFR	Non-caries	33	13.82±3.51	0.267	0.671
	Caries	34	13.36±2.99
NSFR	Non-caries	33	3.81±2.41	0.112	0.826
	Caries	34	3.79±2.37
SV	Non-caries	33	2.92±2.34	0.512	0.627
	Caries	34	2.13±1.22
SBC	Non-caries	33	7.48±2.31	0.652	0.534
	Caries	34	7.13±2.33

SSFR: stimulated salivary flow rate, NSFR: non-stimulated salivary flow rate, SV: salivary viscosity, SBC: salivary buffering capacity.

5. Correlation between caries activity test methods

The amount of irritated salivary secretion had a significant positive correlation with the amount of non-stimulated salivary secretion (p<0.001), and salivary consistency and salivary buffering capacity were significantly positive. Function showed a negative correlation (p<0.05), (Table 6).

Table 6 . Correlation between caries activity test methods

Item		SSFR	NSFR	SV	SBC
SSFR	r	1
	p
NSFR	r	0.823	1
	p	0.000
SV	r	−0.402	−0.136	1
	p	0.024	0.340
SBC	r	−0.401	−0.545	0.087	1
	p	0.017	0.000	0.487

SFR: stimulated salivary flow rate, NSFR: non-stimulated salivary flow rate, SV: salivary viscosity, SBC: salivary buffering capacity.

Oral health is important in pursuing quality of life, and saliva, one of the important causal factors that regulate oral health, is known to be related to the occurrence of oral diseases, especially dental caries, as part of the host factor [17]. Saliva provides moisture to the oral mucosa to prevent it from drying out, improves appetite, provides lubrication when eating or speaking, and acts as a buffer against acids and bases in the oral cavity [18]. In addition, it suppresses the occurrence of dental caries, provides ions necessary for remineralization of teeth, and contains digestive enzymes [19], so it not only helps digest food, but also has antibacterial, antifungal, and antitoxin effects [20]. Before dental treatment. Saliva, which is a tool for assessing changes in subsequent management and health status and an important indicator for evaluating the oral health status of individuals and groups, is one of the factors to be considered when developing an oral health index. In general, it is known that if the amount of saliva secreted is high, the possibility of caries occurrence is low, if the consistency of saliva is high, the caries incidence rate is high, and if the pH of saliva is low, the risk of caries development is high [8,9].

The amount of saliva secreted varies depending on various physical and mental conditions and may be temporarily reduced [10]. In addition, considering the relationship between the amount and consistency of saliva secretion and dental caries, it is known that the greater the amount of saliva secreted and the lower the consistency of saliva, the lower the morbidity rate of dental caries [21].

Dental caries has the characteristic of being a multifactorial disease caused by the interaction of three factors, host factors, bacterial factors, and environmental factors, and temporal factors. However, even if various causative factors act uniformly, dental caries disease may or may not occur depending on the characteristics of each individual. Therefore, in order to effectively prevent dental caries, the unique factors that cause dental caries in each individual must be found and removed [22]. Environmental factors are factors that can be controlled by changing environmental factors in the oral cavity, and are the easiest way to remove dental caries. The degree of occurrence of oral diseases is influenced by differences in each individual’s internal tooth composition, tooth structure, amount of saliva, consistency of saliva, buffering capacity of saliva, oral structure, and oral environment management ability, as well as other family or social members. It is believed that many factors, such as habits and level of education on thorough oral environment management, will be applied [13]. Klock and Krasse [23] studied S. mutans, Lactobacilli, saliva buffering action, saliva secretion rate, saliva pH, and amount of plaque in saliva as factors predicting dental caries activity, and found that S. mutans and dental caries activity were. A significant positive correlation was shown, and the correlation coefficient was 0.21. The amount and consistency of saliva secretion are closely related to the self-cleaning effect of the tooth surface. When the amount of saliva secretion is significantly reduced, the frequency of occurrence of dental caries relatively increases, and the consistency increases, resulting in a greater incidence of dental caries. In other words, if saliva with a high consistency is secreted in a small amount, the oral environment becomes unclean and dental caries disease easily occurs. According to a study conducted by Mercer on American youth, the average amount of non-irritating saliva secreted over 5 minutes was 3.7 ml, and the amount of irritated saliva secreted was 13.8 ml. In the case of irritated saliva, if it is less than 8.0 ml, it should be examined with interest. claimed [12]. Miller [21,22] reported that dental caries often occurs when saliva secretion is not present, and Jeong et al. [24] reported that there is an inverse correlation between the number of teeth experiencing caries and the saliva secretion rate. In the study by Choi et al. [25], the average irritant saliva secretion amount was found to be 6.74 ml, whereas in this study, it was higher at 12.94 ml, and the average non-irritant saliva secretion amount was also found to be 3.89 ml, showing almost similar results to Mercer’s study. In Mercer’s study, the average specific viscosity of the irritating saliva was reported to be 1.3-1.4, and in the study by Choi et al. [25], it was 1.71, which was higher than Mercer’s study, while the average specific viscosity of the irritating saliva of the subjects in this study was 1.57.

Looking at the relationship between the amount of saliva secretion and dental caries, Lee [26,27] collected saliva from 6-year-old children and conducted a study on the effect on the occurrence of dental caries. As a result, he reported that non-irritating saliva secretion amount was significant in the occurrence of dental caries, but in this study, Similar to the research results of Choi et al. [25] and Jo et al. [28], there was no significant difference. It is said that there is a significant difference in the degree to which dental caries occurs, and this phenomenon is often caused by differences in the amount and consistency of saliva secreted. In fact, mucous saliva is said to have a lower cleaning effect of hydrous carbon remaining in the oral cavity than serous saliva [23]. It was said that people with high saliva consistency are more prone to dental caries [29,30]. However, the consistency of saliva in this study was slightly lower in the caries group (2.13±1.22) than in the non-caries group (2.92±2.34), but there was no significant difference. As a result of the investigation of the buffering capacity of saliva, the irritating saliva was measured using a saliva-check buffer and the completed results were compared with the color cart after 2 minutes. The average buffering capacity of the group was found to be 7.13±2.33. Although the experimental method was different from the results of Choi et al. [25]. The results (10,5 drops), the average of all subjects surveyed showed a high possibility of dental caries due to insufficient buffering capacity. In addition, in the comparison between the caries group (7.13±2.33) and the non-caries group, the non-caries group (7.48±2.31) was slightly higher, but there was no significant difference, resulting in the same results. Powell et al. [31]. Reported that a significant correlation was recognized between low salivary secretion rate and the occurrence of dental caries in elderly people, but no correlation was recognized with the occurrence of dental caries in children. Therefore, in the future, the correlation between salivary secretion rate and salivary buffering capacity by age group was reported. It is believed that further research is needed. As dental plaque attached to teeth plays an important role in the occurrence of dental caries, measures to remove dental plaque by thoroughly managing the oral environment are effective dental caries prevention methods, and the research results of Lee et al. [27]. Show that oral environment management ability Since it has been reported that there is a very high correlation between the test results and the number of caries teeth and the caries activity test, continued research should be conducted for more detailed analysis. Therefore, through this study, there was a slight difference compared to Mercer’s evaluation criteria (preventive dentistry book standard) using the dental caries activation method, and the case with current dental caries in the oral cavity was not statistically significant compared to the case without dental caries [32-34], dental caries activity was found to be high. In addition, through the correlation between dental caries activity methods, it was found that the higher the irritating saliva secretion rate, the higher the non-irritating saliva secretion rate, and the higher the pH of the hydrogen ion concentration of dental plaque 30 minutes after brushing the teeth with glucose solution [35-37]. Accordingly, through this study, we were able to present basic data on the dental caries experience rate and dental caries activity factors in adults, but there were limitations in identifying factors that uniquely affect individuals due to the inability to apply various caries activity tests, and some adult program participants. It is believed that more specific and diverse approaches to research should be attempted in the future.

In order to find out the different factors that contribute to the occurrence of dental caries depending on the individual participating in the program, saliva secretion rate, saliva consistency, and saliva buffering capacity were investigated to focus on the salivary factor among the factors causing dental caries disease, and the following results were obtained got it.

1. The average number of carious teeth among the survey subjects was 1.82, and the number of extracted teeth due to dental caries was 2.89 and the number of filled teeth was 7.48. Therefore, the average number of teeth with permanent dental caries experience was 12.19

2. According to the dental caries activity test method, the average irritated saliva secretion amount was 12.56±4.15 ml, non-irritated saliva secretion amount was 3.89±1.83 ml, saliva consistency was 1.49±0.69, saliva buffering capacity was 8.51±2.44, and dental plaque hydrogen The ion concentration test was 5.62±0.50 before brushing teeth, 5.23±0.58 at 5 minutes after brushing teeth, 5.25±0.56 at 10 minutes after brushing teeth, 5.29±0.62 at 15 minutes after brushing teeth, 5.34±0.58 at 20 minutes after brushing teeth, 5.40±0.53 at 25 minutes after brushing teeth, It was found to be 5.61±0.59 30 minutes after brushing teeth.

3. The amount of irritated and non-irritated saliva secreted, saliva consistency, and saliva buffering capacity in the non-caries group was higher than that in the caries group, but was not statistically significant. Dental bacterial membrane hydrogen ion concentration did not show overall statistical significance in the relationship with those with ongoing dental caries, but was higher in the non-caries group than in the caries group.

4. The correlation between caries activity test methods showed that the amount of irritated salivary secretion had a significant positive correlation with the amount of non-irritated salivary secretion (p<0.001), and the amount of non-irritated salivary secretion had a negative correlation with the salivary buffering capacity (p<0.01). The dental plaque hydrogen ion concentration test showed a positive correlation with the passage of time after brushing, but there was no significant correlation with saliva consistency and saliva buffering capacity (p>0.05).

As a result, the salivary secretion amount, salivary point roughness, and saliva buffering capacity results of the dental caries activity test of the study subjects suggest that they are related to dental caries.

No potential conflict of interest relevant to this article was reported.