ORIGINAL RESEARCH |
https://doi.org/10.5005/jp-journals-10015-2340 |
Effect of Brushing the Teeth after Meals on Salivary pH of Elderly People with Removable Dentures: A Quasi Experimental Study
1,2Department of Conservative Dentistry, Faculty of Dentistry, Universitas Trisakti, Jakarta, Indonesia
Corresponding Author: Eko Fibryanto, Department of Conservative Dentistry, Faculty of Dentistry, Universitas Trisakti, Jakarta, Indonesia, Phone: +62215672731 ext 1407, e-mail: eko.fibryanto@trisakti.ac.id
Received: 02 November 2023; Accepted: 06 December 2023; Published on: 31 January 2024
ABSTRACT
Aims: To analyze differences in salivary pH before eating, and at 5, 30, and 60 minutes after eating before brushing teeth, and after brushing teeth in elderly using removable partial dentures.
Materials and methods: This is a quasi-experimental study with a pretest–posttest control group design. The study included a total of 22 participants who were required to eat rice. The participant provided saliva samples before eating, and for 3 consecutive days after eating with different time intervals before and after brushing the teeth. The time intervals were categorized as 5 minutes after eating (T0), 30 minutes after eating (T1), and 60 minutes after eating (T2). On the first day, saliva samples were taken before eating, at T0 before brushing teeth, and after brushing teeth. The exact process was repeated on the 2nd and 3rd days with T1 and T2. Saliva was collected in sterile tubes, stored in a cooler box, and measured with a pH meter. The data were analyzed using the general linear model (GLM) repeated measures analysis of variance (ANOVA) (p < 0.05), one-way ANOVA test (p < 0.05), and independent t-test (p > 0.05).
Results: There was a significant difference in the group after eating before brushing their teeth with an average pH of 5.86 ± 0.22 (T0); 6.48 ± 0.12 (T1); and 6.64 ± 0.15 (T2) and after eating after brushing your teeth with an average pH of 7.26 ± 0.07 (T0); 7.30 ± 0.06 (T1); and 7.32 ± 0.04 (T3), respectively. There wasn’t any significant difference in the pH between the upper and lower jaw of removable partial dentures in each time group.
Conclusion: Salivary pH is typically acidic in the morning. Eating causes a decline in saliva pH, and the elderly have limited saliva buffering capacity to restore pH to neutral. Brushing teeth 5 minutes after eating brings salivary pH back to neutral. There were no significant differences in salivary pH between elderly individuals using upper or lower-jaw removable partial dentures. These findings emphasize the crucial role of timely toothbrushing in preserving oral health among the elderly.
Clinical significance: There were significant findings in the acidity of salivary pH in the elderly using removable partial dentures and the correct time to brush their teeth after meals. Understanding this could help prevent carries and determine the right time to brush their teeth.
How to cite this article: Fibryanto E, Sutanto AVR. Effect of Brushing the Teeth after Meals on Salivary pH of Elderly People with Removable Dentures: A Quasi Experimental Study. World J Dent 2023;14(12):1027–1031.
Source of support: Nil
Conflict of interest: None
Keywords: Elderly, Removable partial dentures, Salivary pH, Time to brush teeth
INTRODUCTION
Life expectancy is assumed to increase as a person’s age, social, economic, health, and educational characteristics improve. Life expectancy in Indonesia has steadily risen over the years, along with the number of elderly people. According to the Ministry of Health of the Republic of Indonesia, the elderly population has increased from 18 million people in 2010 and is predicted to further rise to 48.2 million people by 2035. As the elderly population grows, it is critical to pay attention to their health, particularly their oral health.1–4
The Indonesian Basic Health Research in 2018 revealed that the decayed, missing, filled teeth (DMFT) index score is increasing in Indonesia as age advances among the elderly. The score for ages 55–64 years is 12.6, and for those over 65 years, it’s 16.8. The score that notably increases in these two age-groups is the missing tooth, which is 5.9 at ages 55–64 years and 10.1 at ages 65 and above. The presence of missing teeth would interfere with mastication. It can be replaced by making dentures.5,6
Oral health is generally maintained by saliva. Saliva lubricates the oral mucosa, protects against microorganisms, and helps teeth remineralize. Saliva consists of 99.5% water, 0.5% protein and electrolytes. One of the compositions in saliva that affect the protection of teeth against caries is carbonate. It neutralizes the salivary pH as a buffer solution that affects the remineralization process.7–9
The pH of saliva changes when eating. Microorganisms in the mouth gather to form a layer called dental plaque. Microorganisms that gather convert and ferment carbohydrates into acidic products which can lower the salivary pH and cause tooth demineralization. Saliva has a normal pH of around 6.2–7.6. When the salivary pH rises above 5.5, saliva becomes a saturated solution containing calcium and phosphate, which can remineralize teeth. When the salivary pH falls below 5.5, saliva transforms into an unsaturated solution, making calcium, hydrogen, and phosphate easily soluble, resulting in tooth demineralization. If the tooth demineralization process continues compared to the remineralization process, caries/cavities will occur.8,10–12
Sekele et al.13 found significant differences with the decayed, missing, filled teeth (DMFT) index by conducting oral health examinations with and without removable partial denture users compared to those who did not use it for 5 years. Declining oral health in removable partial denture users can be caused by grips, elements, and bases that can provide space for food to be trapped so that plaque forms around the teeth.14 Augustin et al.15 found significant differences in dental plaque index by conducting oral health examinations with and without removable partial denture users for 5 years and found an increase in plaque in denture users.
Cleaning plaque can be done by brushing your teeth. Brushing your teeth can clean food residue and stop acid production.16 Apart from brushing your teeth, you need to pay attention to the right time to brush your teeth. Brushing teeth is said to take 30 minutes after eating for the pH to return to normal.17 According to Fibryanto and Widyastuti,18 there was no significant difference in salivary pH when brushing teeth within 5, 30, or 60 minutes after eating in individuals 19–22 years. Based on this, the difference in salivary pH between the time before eating; after eating with intervals of 5, 30, and 60 minutes; and after brushing teeth in elderly users of removable partial dentures needs to be done. This study aims to analyze differences in salivary pH before eating, and at 5, 30, and 60 minutes after eating, both before and after brushing teeth in elderly using removable partial dentures.
MATERIALS AND METHODS
Ethical approval for this research was granted by the Health Research Ethics Commission of the Faculty of Dentistry, Universitas Trisakti, with approval number 554A/S1/KEPK/FKG/8/2022, on August 18, 2022. The research was conducted from September to December 2022, following the ethical principles outlined in the Declaration of Helsinki for medical research involving human subjects. This study employed a quasi-experimental design with a pretest–posttest control group. The research took place at Suaka Kasih Nursing Home in South Kalimantan, and the study population consisted of elderly individuals residing in the nursing home. The total sampling technique was used to select the participants. The sample for this study comprised saliva obtained from 22 individuals, with 11 individuals using only upper dentures and 11 individuals using only lower dentures. Before participation, informed consent was obtained from all subjects.
The inclusion criteria for this research included individuals aged 60 and over, who used a maxillary or mandibular acrylic/thermoplastic/metallic framework removable partial denture or both to replace missing teeth, took off their removable partial denture while sleeping, had controlled systemic disease, brushed their teeth with modified bass and horizontal technique, had their removable partial denture cleaned with a denture cleaner, and consumed rice for breakfast. These inclusion criteria were observed through intraoral examination and questionnaires. Exclusion criteria for this research included individuals who wore complete dentures, underwent radiation therapy and had autoimmune diseases.
Researchers used personal protective equipment every time samples were taken, consisting of medical masks (Keholl, Rui’an, and China), face shields (me Shield, Kuningan, Indonesia), and gloves (Sri Tang Gloves, Songkhla, and Thailand). Subjects were given instructions on how the research was carried out, how to brush their teeth using a toothbrush and toothpaste (Pepsodent, Unilever, Tangerang, and Indonesia), and how to clean removable partial dentures with a toothbrush (Pepsodent, Unilever, Tangerang, and Indonesia) along with denture cleanser (Pearlie White, Ang Mo Kio, and Singapore). Additionally, the subjects were required to eat rice. The saliva that was collected consisted of unstimulated saliva stored in sterile tubes (Labware, Delaware, and United States) in 10 mL volumes. The research was conducted in the morning, and after collecting all the saliva sample tubes, they were stored in a 4°C cooler box (I-15MARNA Cooler Box 6S, Lion Star, Jakarta, and Indonesia).
The study included a total of 22 participants, with 11 wearing upper dentures and 11 wearing lower dentures. The participant provided saliva samples before eating, and for 3 consecutive days after eating with different time intervals before and after brushing the teeth. The time intervals were categorized as 5 minutes after eating (T0), 30 minutes after eating (T1), and 60 minutes after eating (T2) to distinguish the groups. On the 1st day, saliva samples were taken before eating, at T0 before brushing teeth, and after brushing teeth. The exact process was repeated on the 2nd and 3rd days with T1 and T2. Each participant was instructed to spit into a storage tube before and after breakfast following the time intervals, and only allowed to drink water. After collecting the sample after eating, the participants removed their partial dentures and brushed their teeth. The researchers assisted in cleaning the partial dentures using a toothbrush and denture cleanser. Following tooth brushing, the participants were instructed to spit the saliva into sterile tubes, which were then stored in a cooler box. Saliva samples were analyzed using a pH meter (Digital Automatic Calibration P-2Z-B1900126, Mediatech, Jakarta, Indonesia) within a maximum time of 6 hours after collection. To increase data collection, participants wearing upper dentures and lower dentures were differentiated and underwent the same sampling procedure.
Data analysis was conducted to compare the salivary pH values at different brushing times, namely T0, T1, and T2, using the general linear model (GLM) repeated measures analysis of variance (ANOVA) (p < 0.05). Within each time group, a one-way ANOVA test was performed to assess the differences (p < 0.05). Furthermore, an independent t-test was used to compare the pH values between elderly individuals wearing upper and lower removable partial dentures (p > 0.05). The data were analyzed using IBM Statistical Package for the Social Sciences (SPSS) 25 software (SPSS Inc., Chicago, Illinois).
RESULTS
The individuals for this study comprised saliva obtained from 22 elderly individuals with an average age of 74 years old, consisting of nine males (41%) and 13 females (59%) with 11 individuals using only upper dentures (50%) and 11 individuals using only lower dentures (50%). The data followed a normal distribution based on the Shapiro–Wilk test (p > 0.05). The results of the GLM repeated measure ANOVA indicated significant differences in salivary pH between the time intervals before and after eating and after brushing teeth within each group (p < 0.05). The average initial salivary pH before and after breakfast in T0 was 6.55 ± 0.16 and 5.86 ± 0.22, respectively, as well as the salivary pH after brushing teeth was 7.26 ± 0.07 (Table 1). Similarly, T1 exhibited an average initial salivary pH after breakfast of 6.48 ± 0.12 and a salivary pH after brushing teeth of 7.30 ± 0.06. T2 showed an average initial salivary pH after breakfast of 6.64 ± 0.15 and a salivary pH after brushing teeth of 7.32 ± 0.04.
Time | n | Average ± SD (pH) | p |
---|---|---|---|
Before eating | 22 | 6.55 ± 0.16 | 0.01* |
5 minutes after meals, before brushing teeth | 5.86 ± 0.22 | ||
5 minutes after meals, after brushing teeth | 7.26 ± 0.07 | ||
Before eating | 22 | 6.55 ± 0.16 | 0.01* |
30 minutes after meals, before brushing teeth | 6.48 ± 0.12 | ||
30 minutes after meals, after brushing teeth | 7.30 ± 0.06 | ||
Before eating | 22 | 6.55 ± 0.16 | 0.01* |
60 minutes after meals, before brushing teeth | 6.64 ± 0.15 | ||
60 minutes after meals, after brushing teeth | 7.32 ± 0.04 |
ANOVA, analysis of variance; *, general linear model (GLM) repeated measure ANOVA (p < 0.05); SD, standard deviation
One-way ANOVA test demonstrated a significant difference in salivary pH before brushing between T0 (5.86 ± 0.22), T1 (6.48 ± 0.12), and T2 (6.64 ± 0.15) (p < 0.05). This test also revealed a significant difference in salivary pH between groups that brushed their teeth after T0 (7.26 ± 0.07), T1 (7.30 ± 0.06), and T2 (7.32 ± 0.04) (p < 0.05) (Table 2). Moreover, when comparing the salivary pH values between elderly individuals using the upper and lower jaw of removable partial dentures, an independent t-test found no significant difference (p > 0.05) (Table 3).
Time | n | Average ± SD (pH) | p |
---|---|---|---|
T0 before brushing teeth | 22 | 5.86 ± 0.22 | 0.01* |
T1 before brushing teeth | 6.48 ± 0.12 | ||
T2 before brushing teeth | 6.64 ± 0.15 | ||
T0 after brushing teeth | 22 | 7.26 ± 0.07 | 0.01* |
T1 after brushing teeth | 7.30 ± 0.06 | ||
T2 after brushing teeth | 7.32 ± 0.04 |
ANOVA, analysis of variance; *One-way ANOVA (p < 0.05); SD, standard deviation; T0, 5 minutes after eating; T1, 30 minutes after eating; T2, 60 minutes after eating
Removable partial denture | n | Average ± SD (pH) | Mean difference | p |
---|---|---|---|---|
Upper RPD user before eating | 11 | 6.60 ± 0.12 | 0.11 | 0.95 |
Lower RPD user before eating | 6.49 ± 0.17 | |||
Upper RPD 5 minutes after eating before brushing teeth | 11 | 5.84 ± 0.23 | −0.04 | 0.67 |
Lower RPD 5 minutes after eating before brushing teeth | 5.88 ± 0.23 | |||
Upper RPD 5 minutes after eating after brushing teeth | 11 | 7.29 ± 0.05 | 0.05 | 0.09 |
Lower RPD 5 minutes after eating after brushing teeth | 7.23 ± 0.09 | |||
Upper RPD 30 minutes after eating before brushing teeth | 11 | 6.46 ± 0.10 | −0.05 | 0.35 |
Lower RPD 30min after eating before brushing teeth | 6.51 ± 0.14 | |||
Upper RPD 30 minutes after eating after brushing teeth | 11 | 7.30 ± 0.07 | 0.01 | 0.77 |
Lower RPD 30 minutes after eating after brushing teeth | 7.30 ± 0.05 | |||
Upper RPD 60 minutes after eating before brushing teeth | 11 | 6.62 ± 0.16 | −0.02 | 0.70 |
Lower RPD 60 minutes after eating before brushing teeth | 6.65 ± 0.15 | |||
Upper RPD 60 minutes after eating after brushing teeth | 11 | 7.31 ± 0.03 | −0.03 | 0.09 |
Lower RPD 60 minutes after eating after brushing teeth | 7.34 ± 0.05 |
*, Independent t-test (p < 0.05); RPD, removable partial denture; SD, standard deviation
DISCUSSION
This research demonstrated that the saliva of elderly individuals using removable partial dentures in the morning tended to be acidic, with a pH of 6.55 ± 0.16. The pH value in this study was similar to the salivary pH of adults aged 19–22 years old without removable partial dentures (ranging from 6.52 ± 0.16 to 6.73 ± 0.22), as reported in the study conducted by Fibryanto and Widyastuti 18 in 2016. The acidic tendency in pH can be attributed to a decrease in salivary flow during sleep at night.12,18 Saliva secretion follows a circadian rhythm and is regulated by the sympathetic and parasympathetic nervous systems. The parasympathetic nervous system stimulates fluid secretion in the salivary gland located in the medulla nucleus, while the sympathetic nervous system stimulates protein secretion in the salivary gland through the superior cervical ganglion. The decrease in salivary secretion during sleep is associated with reduced parasympathetic stimulation in the medulla, leading to decreased blood flow to the salivary glands and decreased saliva secretion by acinar cells. Furthermore, the cortisol hormone in saliva decreases during sleep, mediated by melatonin, which is involved in regulating circadian rhythms. The decline in melatonin levels in saliva results in reduced saliva secretion.19–22 Interestingly, the present study found no significant difference in morning pH values between adults and elderly individuals using removable partial dentures, despite the expected salivary gland atrophy in the elderly. This can be attributed to the presence of minor salivary glands that also contribute to maintaining the pH balance in the oral cavity.20 Additionally, it was observed that the average salivary pH decreased within 5 minutes after eating. This decline in pH can be attributed to the interaction between oral bacteria and carbohydrate-containing foods, which produce acidic by-products.10
Significant differences were observed in pH values at T0, T1, and T2 before brushing teeth. According to the buffer function of saliva, the oral environment should return to a neutral pH within the first 20–30 minutes.12 However, in the elderly, this buffering ability is insufficient to restore salivary pH to neutral within that timeframe while it proved that the buffer function tried to return the pH to normal (pH < 7).23,24 Studies from Firbyanto and Widyastuti18 reported that pH values of 7.10 ± 0.16 and 7.22 ± 0.16 within 30 and 60 minutes after eating on 15 adults without any denture, respectively. These findings suggest that the buffer function of saliva in adults can neutralize pH more efficiently compared to the elderly. The lower salivary pH in the elderly using removable partial dentures at T1 and T2, compared to the pH of adults, may be attributed to decreased buffering ability resulting from acinar cell atrophy and degeneration of the salivary glands.23–25 Salivary buffers, which contain carbonate, neutralize saliva by binding to hydrogen ions and forming water and carbon dioxide. Insufficient carbonate compounds cannot restore the pH of saliva to neutral.9,20,26
The use of removable partial dentures and systemic drugs consumed by the elderly can also contribute to an acidic salivary pH. Removable partial dentures have grips and a base that can retain food particles, preventing saliva from neutralizing the oral environment.27 In this research, all elderly participants were using the systemic hypertension drug amlodipine. Amlodipine, an antihypertensive drug that blocks calcium channels, inhibits salivary gland secretion by reducing stimulation through M3 muscarinic receptors.28,29
The present study reveals significant differences in salivary pH between the observation groups after eating but before brushing their teeth. The pH values at 5, 30, and 60 minutes after eating but before brushing teeth were 5.86 ± 0.22, 6.48 ± 0.12, and 6.64 ± 0.15, respectively. Brushing teeth after eating can neutralize acidic saliva by removing food residue and plaque.16,18,30 The current research demonstrated that brushing teeth at T0 by elderly individuals using removable partial dentures can restore the salivary pH to 7.26 ± 0.07. These results are consistent with previous studies from Fibryanto and Widyastuti18 reporting pH values above 7.
The neutralization of salivary pH after brushing teeth can be attributed to mechanical stimulation during brushing and the use of the same toothpaste in the study. Brushing teeth stimulates the salivary glands, leading to increased saliva secretion, which helps neutralize the oral environment.31 The toothpaste used in this research contained calcium carbonate, fluoride, and sodium lauryl sulfate. Calcium carbonate serves a similar function to saliva buffers, while fluoride aids in tooth remineralization by replacing hydroxyl groups and converting hydroxyapatite to fluorapatite. Hydroxyl ions released from the reaction between hydroxyapatite and fluoride can neutralize the hydrogen ions produced by bacterial activity, thereby increasing the pH of saliva. Sodium lauryl sulfate reduces the surface tension of plaque, making it easier to remove food debris and residues from the tooth surface.32,33
The appropriate toothbrushing technique can be adapted to the oral conditions of elderly individuals. Those with healthy gingiva can still use the modified bass brushing technique for the interproximal area and the horizontal technique for the occlusal area. However, this research also identified elderly individuals with gingival recession, who may benefit from switching to the charter technique for the interproximal area and the horizontal technique for the occlusal area. The charter technique involves placing the bristle at a 45° angle from the gingiva toward the occlusal side of the tooth.34,35
The relationship between tooth brushing and the time elapsed after eating is a topic of debate. Some studies have reported enamel damage resulting from tooth brushing after eating, due to the softer enamel in an acidic environment and the limited ability of saliva to remineralize teeth under acidic conditions.36,37 On the contrary, Bartlett et al.38 found no effect on tooth wear when individuals waited a certain period after breakfast before brushing their teeth, as evidenced by studies involving a large number of subjects. The present study aligns with the findings of Bartlett et al.,38 suggesting that brushing teeth 5 minutes after eating can be recommended for elderly individuals using removable partial dentures. Brushing teeth within 5 minutes after eating can restore the salivary pH to neutral, eliminating the need to wait for 30 or 60 minutes after eating. Waiting for 30 or 60 minutes after eating does not necessarily restore the salivary pH to neutral.
The current study illustrates that both the upper and lower jaws of individuals using removable partial dentures exhibit relatively low pH values, especially at 30 and 60 minutes after eating. These low pH values are associated with decreased salivary function in the elderly.23,39 Thus, the diminished buffering ability observed in the elderly affects the oral environment as a whole, regardless of whether they wear an upper or lower jaw denture.12 The presence of major salivary glands, compensated by the minor salivary glands surrounding the oral mucosa, contributes to saliva production and helps maintain the pH balance.12,39,40
The limitations of this study are that the sample size of elderly individuals using removable partial dentures was relatively small because it was conducted during the pandemic era, which limited the permission to work with another nursing home. With a limited sample, the generalizability of the findings may be affected. Despite these limitations, this study provides valuable insights into the salivary pH of elderly individuals with removable dentures to maintain oral health. Further studies are needed to assess the pH differences between elderly individuals who do not receive dental brushing education and those who do. Additionally, research is required to compare elderly individuals with physical limitations to those without.
CONCLUSION
Salivary pH is typically acidic in the morning. Eating causes a decline in saliva pH, and elderly individuals with removable dentures have limited saliva buffering capacity to restore pH to a neutral level. However, brushing teeth within 5 minutes after eating effectively brings salivary pH back to a neutral range for these individuals. Notably, there were no significant differences in salivary pH between elderly individuals using upper or lower-jaw removable partial dentures. These findings emphasize the crucial role of timely tooth brushing in preserving oral health among the elderly.
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