|Year : 2021 | Volume
| Issue : 4 | Page : 241-249
Effect of yoga on periodontal health – A systematic review and meta-analysis
Veena Kalburgi, Nimmala Sai Sri Harsha
Department of Periodontics, People's College of Dental Sciences and Research Centre, Bhopal, Madhya Pradesh, India
|Date of Submission||09-Aug-2021|
|Date of Decision||09-Oct-2021|
|Date of Acceptance||29-Oct-2021|
|Date of Web Publication||20-Dec-2021|
Department of Periodontics, People's College of Dental Sciences and Research Centre, Bhanpur, Bhopal - 462 037, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
Yoga is a holistic and ancient practice that traces its origins back about 3000 years and enables us to be more productive by activating all of the body's functions. The name yoga itself means union, intertwining of body, brain, and soul. Yoga can prevent periodontal diseases. This may sound extraneous, but it is a scientifically proven truth; yoga will prevent not only periodontal disease but also many other systemic diseases. A search was done to find the articles that have been published on various databases Medline/PubMed, Google Scholar, LILACS, Cochrane, OpenGrey, and USC Upstate Library. We included only original research studies which clearly explain the influence of yoga on periodontitis with specified result. Meta-analysis was done of the clinical periodontal parameters used for observation of the periodontal health in the selected studies. Five studies were selected after analyzing various factors, and coincidentally, all the selected studies were from various regions of India. Forest plots were made of the studies selected. We conclude very clearly from the analysis done that yoga, an ancient practice, has a favorable impact on human body in stress control, henceforth maintaining the periodontal health.
Keywords: Cortisol, periodontitis, stress, yoga
|How to cite this article:|
Kalburgi V, Sri Harsha NS. Effect of yoga on periodontal health – A systematic review and meta-analysis. J Dent Res Rev 2021;8:241-9
|How to cite this URL:|
Kalburgi V, Sri Harsha NS. Effect of yoga on periodontal health – A systematic review and meta-analysis. J Dent Res Rev [serial online] 2021 [cited 2022 Jan 18];8:241-9. Available from: https://www.jdrr.org/text.asp?2021/8/4/241/332922
| Introduction|| |
Yoga is a historical practice that originated in the ancient times of India, one among the 6 astika (Hindu philosophical schools, Sankhya, Yoga, Nyaya, Vaisheshika, Mimamsa, and Vedanta). The name yoga originated from a word in Sanskrit “yuj” which means “to unite” the body, brain, and soul. Yoga is proved as the most effective and valuable practice for man to treat many psychological and physical problems. According to many researches, yoga's role in stress reduction is proved and enhancing perceptive skills. Some psychological factors, such as anxiety and stress, have a direct impact on the pathogenesis of some diseases. Moreover, stress is responsible for inflammatory destruction, and makes an individual much prone to several diseases, including periodontitis. Yoga leads to decreased levels of stress which helps an individual in reduction of anxiety and depression, and also aids in reduction of pain, inflammation and also improves immune system.
The reason for deprived life quality, lower mental health, reduced work efficiency, greater suffering, and increased physician visits and personality disorders is stress. Stress has become a problem of community health concern and the yoga practice, which promises to be an approach to combat it. A significant increase of T-helper cells (CD8+) and natural killer cells was noticed, when an individual is under acute stress and returns to their normal values after a while. Several neuropeptides (substance P and somatostatin) get released and also affect the actions of immune system and the cytokines get released.
Many studies were done, which clearly state that stress affects the periodontium. Periodontitis is a chronic inflammatory disease characterized by episodes of active destruction to pronounced inflammatory infiltration, attachment loss, and alveolar bone loss. According to some studies, stress impacts an individual's behaviour and health in ways such as neglecting oral hygiene, decreased intake of food, increased frequency of smoking , and increased alcohol consumption, all of which affect collagen synthesis and ultimately result in periodontal diseases. Neglecting the maintenance of oral hygiene leads to accumulation of plaque on the teeth oral mucous membranes, and other tissues present in the mouth, which contains mainly microorganisms which increase the periodontitis risk. An article stated that stress caused by any reason decreases the immune system action by activation of hypothalamic–pituitary–adrenal axis (HPA axis) by which adrenocorticotropic hormone gets released from anterior pituitary gland which increases the cortisol secretion from adrenal cortex. Cortisol reduces the secretion of immunoglobulin A and immunoglobulin G and decreases the functioning of neutrophils, thus increasing the susceptibility to periodontal destruction., Stress also directly stimulates the autonomous nervous system, further stimulating the adrenal medulla secreting the epinephrine and norepinephrine, which further leads to altered immune response and increased blood glucose, increasing the periodontal disease risk, as shown in [Figure 1].
|Figure 1: Mechanism of yoga on periodontal health (Ankerberg and Weldon, 1996, and Saatcioglu, 2013)|
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Periodontitis is an oral disease which is commonly found and can be seen in a severe form in 15%–20% of the global population among the age group of 35–44 years, and it increases to 70.1% in the population aged 65 years and above. It occurs in individuals who are exposed to high levels of stress and poor oral hygiene and suffering from systemic conditions such as hypertension and diabetes mellitus. The bacterial plaque, microbial by-products, and host immune response are the factors that cause the periodontitis. The main characteristics of the disease include loss of clinical attachment, periodontal pocket formation, and apical migration of epithelial attachment called gingival recession. Decreased inflammatory markers can be noticed in the individuals who are physically dynamic than the people practicing a sedentary lifestyle. Pro-inflammatory cytokines (for example, interleukin-6 [IL-6] and tumor necrosis factor-alpha) are responsible for the progression of periodontal disease. Physical exercise is linked to lower levels of IL-6 and pro-inflammatory cytokines when done regularly. As a result, yoga has a reversible impact on depression- and stress-related periodontitis, and can also act as an adjunct after the periodontal therapy to recess the inflammation and pro-inflammatory cytokines. Yoga increases the production of anti-inflammatory cytokines such IL6, which reduces inflammation. However, IL6 can act as both a proinflammatory and an antiinflammatory cytokine.
Yoga acts on body in several ways to decrease the stress, energizes immune system to act against pathogens, and also stimulates vagus nerve to set body into resting state during stressful conditions. Yoga practice suppresses the HPA axis, leading to decreased production of cortisol, ultimately decreasing the stress. Decrease in stress leads to balanced inflammatory response by release of necessary cytokines. As periodontitis is an inflammatory condition, it proves that yoga is helpful in maintaining a healthy periodontium. Other than the stress, it stimulates parasympathetic nerves conserving the energy by slowing heart rate, and release hormones that help to relax and calm down. Autonomic nerves play a very important role in stress mechanism, Sympathetic nerves work while an individual is in stress, and the recovery from stress is done by parasympathetic nervous system. Yoga effects on body and periodontium are briefly summarized in [Figure 2]. It is proven that stress is reduced by practicing yoga, thus risk of diseases including periodontal diseases is reduced. Oxygen plays a vital role in inflammation, as it was observed in the previous studies that the oxygen saturation is relatively low in the inflamed gingiva than the normal gingiva. The oxygen consumption of the normal gingiva was 1.6 ± 0.37, as was found to be altered in the inflamed tissues. It is a known fact that oxygen and inflammation are interrelated. The inflammation is caused when the blood supply to a tissue fails to meet the oxygen demand. The breathing exercises in yoga like pranayama, help in increasing the lung capacity, leading to the elevated oxygen supply to the tissue through circulation, thereby helping in the reduction of inflammation.
|Figure 2: Effects of yoga on body helping ultimately to maintain healthy periodontium|
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| Methodology|| |
Cochrane standards of systematic review were followed for designing the protocol of the analysis and the search criteria along with the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) protocol guideline.
Types of studies included are comparative descriptive study, and case–control studies, as they can answer the research question by comparison of periodontal condition between individuals that who do and who do not practice yoga. These types of studies can clearly state the influence of practicing yoga on periodontal disease, which helps reviewers for stating the conclusion from the selected studies.
Participants inclusion/exclusion criteria
Studies with participants who are systemically healthy and not under stress are included. There are mainly two groups under inclusion criteria: (a) systemically healthy participants who do yoga practice regularly and (b) systemically healthy participants who do not practice yoga. The oral condition of the participant was not taken into consideration, during the selection of studies. All the studies had used any of these following clinical parameters for detecting the periodontal condition, i.e., plaque index (PI), gingival index (GI), debris index, calculus index, oral hygiene index (OHI), Probing pocket depth (PPD), and Clinical attachment loss (CAL).
Method of search
A search was done for articles that have been published on various databases Medline/PubMed, Google Scholar, LILACS, Cochrane, OpenGrey, and USC Upstate Library. The terms used for searching the articles were Yoga, Chronic Periodontitis, Serum Cortisol, and Stress. The strategy used for searching the related articles in various databases was “(((((Yoga) AND (Chronic periodontitis)) OR (Periodontal health)) OR (periodontium)) AND (Stress)) OR (Cortisol).”
Eligibility and data extraction
We have assessed all the search results that were displayed by using keywords and have excluded many articles by title, duplicate studies, reviews, abstract, study types, methods, and selection of subjects in the particular study. We included only original research studies which clearly explain the influence of yoga on periodontitis with specified result. The studies qualifying the criteria of inclusion were analyzed and then extraction of data was done. The data were retrieved from the studies, such as the location of research, the size of the study's participants, the study's inclusion criteria, clinical parameters measured in the participants, and treatment offered, if any [Table 1]. The primary outcome of the study is the oral health of the participants practicing yoga, and the PI, GI, CAL, and PPD remain the secondary outcomes.
This meta-analysis is done to find out whether there is any influence on periodontal tissue health by practicing yoga or not. Both the groups who regularly practice yoga and who do not practice yoga were considered, and certain clinical parameters such as GI, PI, probing pocket depth, and calculus index were recorded in various studies. Due to expected heterogeneity between the studies, the model used was the random-effects model. A meta-analysis done for each clinical parameter measured of various included studies is presented by using forest plots with means, standard deviation, sample sizes, and mean differences.
| Results|| |
Records that were identified by searching databases were 591 and 32 from other sources, and found 289 duplicate results which were excluded. While assessing the titles of the articles, another 286 articles that did not qualify the selection criteria were excluded. Total abstracts of 48 records were screened and 34 were excluded after reading the abstract. There were 14 full-text articles that were suitable for consideration. Among them, nine records were excluded based on the type of study and methods of selection and also the clinical parameters measured. After thorough assessment, five studies of similar types done in various areas of India were considered and included for qualitative and quantitative synthesis. [Figure 3] illustrates the model of complete search following the PRISMA guidelines and criteria of inclusion.
|Figure 3: Preferred Reporting Items for Systematic Review and Meta-Analysis flowchart of study selection|
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Characteristics of studies
The study selection was done by considering numerous factors such as method used for selection of study participants, study group, and clinical parameters measured. There were five studies in total that are selected on the basis of criteria of inclusion and characteristics of each study included [Table 1]. All the studies included were comparative descriptive studies with a group of people practicing yoga regularly and another not practicing yoga; some studies showed up some additional groups which were not taken into consideration. Clinical parameters taken into consideration are GI, PI, OHI simplified, clinical attachment loss, and probing pocket depth. Although various other parameters were included in the selected studies, only the common parameters among any two or more studies are considered. Results of all the included studies show significantly lower values in a group who regularly practice yoga.
Risk of bias was assessed for the selected studies using Cochrane risk-of-bias tool; the mean risk was high. Random sequence generation (selection bias) was high with Singh et al., 2017, Ramamoorthy et al., 2020, and Katuri et al., 2016, and have a low rate of risk with Rajhans et al., 2018, and Sudhanshu et al., 2017. Allocation concealment bias (selection bias) assessment was done, and the results found were high with all the selected studies. Reporting bias (selective reporting) was assessed, and the results found were low for all studies included. All of the studies had a higher risk of participant and personnel blinding or performance bias. Hence, the mean risk of three studies was high and the remaining two studies were at medium. The overall mean risk of the studies was found to be high. We had to include them as there are limited studies on periodontitis and yoga in the literature. Hence, the selection of the following studies for meta-analysis was necessary. The risk-of-bias assessment of the selected studies is mentioned in [Table 2].
The forest plots were made to address the heterogeneity of the involved studies. A random-effects model is used for the quantitative analysis and calculated at confidence intervals of 95%.
The forest plot was constructed for four studies,,,, with PI as a clinical parameter for determining the periodontal condition between the control group and the group practicing yoga. PI was found to be significantly reduced in the group practicing yoga with Z = 2.29 at P = 0.02. (significant). Forest plot was prepared of the PI of the studies selected and is mentioned in [Figure 4].
|Figure 4: Forest plot showing plaque index of different studies between yoga group and control group|
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Forest plot was constructed considering GI, which was used as the clinical parameter in three studies,, for determining the periodontal condition of the group practicing yoga and control group, there was no significant difference found in the GI score between both groups with Z = 1.80 at P = 0.07 (not significant). Here, based on GI, it cannot be clearly stated any influence of yoga on periodontium according to three studies. Forest plot was prepared for GI of the selected studies and is manifested in [Figure 5].
|Figure 5: Forest plot showing gingival index of different studies between yoga group and control group|
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Forest plot was made for studies which considered clinical attachment level (CAL) as a clinical parameter for the determination of periodontal condition states, and there was a difference seen in CAL score between yoga and control groups with Z = 2.89 at P = 0.004 (significant). Forest plot was prepared of the CAL for the selected studies and is mentioned in [Figure 6].
|Figure 6: Forest plot showing clinical attachment loss in different studies between yoga group and control group|
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Forest plot was constructed considering probing pocket depth (PPD), which was considered a clinical parameter in four studies, for the determination of periodontal condition, it was observed that PPD was significantly reduced in the yoga group with Z = 2.53 at P = 0.01 (significant). According to the acquired PPD values, it is clearly stated that yoga has an influence on periodontium. The forest plot of PPD of the studies selected is mentioned in [Figure 7].
|Figure 7: Forest plot showing probing pocket depth of different studies between yoga group and control group|
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| Discussion|| |
In the present conditions, according to some studies, around 20%–50% of the global population has periodontal diseases. Periodontal diseases are caused by a variety of etiological factors. The most ignored and uncontrollable etiology is stress, which leads to periodontal diseases and even worsens the preexisting periodontitis. Because almost every individual has stress in their life and it is a very common condition which cannot be prevented, yoga practice can resolve this condition. Yoga effects the body in such a way that is much beneficial for the physiologic functioning and even the psychological functioning, ultimately improving the life quality of an individual.,,,,,,, Yoga can abort both the modifiable and nonmodifiable risk factors of periodontal disease, maintaining the periodontal health.
Yoga, which originated in ancient India, is practiced in many regions of the world as of now. In this systematic review and meta analysis, the studies were obtained from databases and only selected studies were included. All the studies were done in India but from various regions like Haridwar, Ahmednagar, Chennai, and Guntur and the area was not specified in one study. In every study, results are in favor of the group regularly practicing yoga. It is seen clearly that there was no influence of area over the obtained results, as the obtained results from all the studies were similar.
Although we found some other similar studies on yoga, stress, and periodontium, we took the clinical parameters measured, place where the study was done (as the prevalence of the disease varies on the basis of geographic location), transparency of study mentioned, and the study method into consideration to minimize the bias, and get accurate results.
Meta-analysis was performed on the measured parameters; significant changes were noticed in PI between the people practicing yoga and people who do not practice in the studies performed by Ramamoorthy et al., 2020, Katuri et al., 2016, Rajhans et al., 2018, and Sudhanshu et al., 2017. The value of P is significant (P = 0.03), with a mean difference of −0.42. A significant reduction of the plaque scores was noticed in all selected studies that prove the decreased plaque content and the increased oral hygiene; in the same manner, GI was analyzed in the studies of Ramamoorthy et al., 2020, Rajhans et al., 2018, and Singh et al., 2017. No significant difference was noticed in the values (P = 0.07), with a mean difference of −0.31. A reduction in scores of GI was noticed in all selected studies that show the healthy gingival condition; the CAL and the PPD were calculated of participants in the studies conducted by Ramamoorthy et al., 2020, Katuri et al., 2016, Rajhans et al., 2018, and Sudhanshu et al., 2017. Significant changes were noticed in CAL between both the groups (P = 0.004) and also the PPD values (P = 0.01), with a mean difference of the CAL as −1.03 and the PPD as −0.69. By these values, it was stated that yoga is effective in maintaining periodontal health.
There are some limitations of the selected studies. Ramamoorthy et al. did not consider women for their study, and the reason for that was not stated. Women might have been excluded due to the frequent hormonal changes that occur, an etiological factor for periodontal tissue inflammation. Along with this, they also stated that another limitation of their study was that the periodontal pathogens were not explored. Our meta-analysis has a limitation itself, as we have ignored the selected participants age in their respective studies, which also acts as a factor of periodontal condition. Sudhanshu et al., 2017, conducted a study in which the participant's age was not considered as an inclusion criterion, a random selection of participants was done (limitation of their particular study). There was no similarity in the participant's age in any of the selected studies. Ramamoorthy et al. considered the age of 18–35 years as an inclusion criterion, where Singh et al., 2017, considered the age of 25–55 years, Rajhans et al., 2018 considered the age of 35–44 years, Katuri et al., 2016, selected participants of age 35–60. Apart from that, the statistical analysis of all selected studies was similar except Katuri et al., 2016, as they analyzed a mean of the sites having the PPD and CAL 5–8 mm and >8 mm, rather than analyzing mean scores of PPD and CAL as the remaining studies done. We have included these studies in spite of these limitations as the literature regarding this particular research question was so limited. Albeit the serum cortisol levels can predict the diagnosis much better, due to insufficient data in the literature to conduct a meta-analysis, we have not analyzed them. There is a need of further similar studies, to prove the yoga effect on periodontitis.
| Conclusion|| |
Stress may lead to many disorders in body because of hormonal imbalance, activating unnecessary cytokines, and altered immune response, and it is a major risk factor for periodontitis. Periodontitis is an inflammatory disease that occurs due to the inflammatory destruction of the periodontium. There are many other factors other than stress such as microbes and smoking that cause or worsen periodontal conditions. With regular yoga practice, one can overcome almost all of the factors that cause periodontitis and achieve a healthy periodontium. Yoga has also been shown to be beneficial for other systemic diseases besides periodontitis. Numerous studies were conducted stating the yoga effect on systemic diseases, but only a few research studies were made on yoga effect on periodontium, so we took a step to bring awareness among the people.
We are grateful to Dr. Sahana Shiv Kumar, Professor and Head, Community Dentistry, People's College of Dental Sciences and Research Centre, for the analysis and support.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
[Table 1], [Table 2]