Article
Original Article

Jasleen Kaur* , Supreet Kaur, Vandana, Sahib Tej Singh, Danish Khindri, Vidhuta Sareen

Department of Periodontonlogy, Sri Guru Ram Das Institute of Dental Sciences and Research, Amritsar, Punjab, India.

*Corresponding author:

Dr. Jasleen Kaur, Postgraduate Student, Department of Periodontonlogy, Sri Guru Ram Das Institute of Dental Sciences and Research, Amritsar, Punjab, India. E-mail: jasleen.kaur694@gmail.com

Received date: 11/11/21; Accepted date: 18/03/22; Published date: 30/09/2022

Year: 2022, Volume: 14, Issue: 3, Page no. 53-60, DOI: 10.26715/rjds.14_3_10
Views: 772, Downloads: 19
Licensing Information:
CC BY NC 4.0 ICON
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0.
Abstract

Background: As with many chronic infections, the initiation and progression of periodontal diseases are modified by local and systemic host conditions, or risk factors, that markedly affect the resistance of the host to infecting periodontal pathogens. There are large number of factors including genetic, environmental, and psychosocial which constitute a substantial risk in the development of periodontal destructive diseases.

Aim: The aim of present study was to scrutinize the relationship between clinical depression, sleep quality and severity of periodontitis using clinical parameters and a depression and sleep quality rating scale.

Materials and Methods: Hundred patients were enrolled in this case-control study, of which 50 patients diagnosed with chronic periodontitis were categorized into cases and 50 patients who were systemically and periodontally healthy were designated as controls. The periodontal parameters recorded included probing depth and simplified oral hygiene index (OHI-S). Depression was determined using Beck’s depression scale. Pittsburgh Sleep Quality Index (PSQI) was used for scrutinizing sleep quality.

Results: Self‑reported scoring of depression and sleep quality by using Beck’s depression inventory and Pittsburgh Sleep Quality Index questionnaire has revealed that patients diagnosed with chronic periodontitis had an appreciable elevated score of depression and poor sleep quality than normal controls.

Conclusion: Findings of this case-control study revealed a statistically significant relationship between depression, its associated oral health behavior, sleep deprivation experienced and severity of destructive periodontal diseases.

<p><strong>Background: </strong>As with many chronic infections, the initiation and progression of periodontal diseases are modified by local and systemic host conditions, or risk factors, that markedly affect the resistance of the host to infecting periodontal pathogens. There are large number of factors including genetic, environmental, and psychosocial which constitute a substantial risk in the development of periodontal destructive diseases.</p> <p><strong> Aim: </strong>The aim of present study was to scrutinize the relationship between clinical depression, sleep quality and severity of periodontitis using clinical parameters and a depression and sleep quality rating scale.</p> <p><strong>Materials and Methods:</strong> Hundred patients were enrolled in this case-control study, of which 50 patients diagnosed with chronic periodontitis were categorized into cases and 50 patients who were systemically and periodontally healthy were designated as controls. The periodontal parameters recorded included probing depth and simplified oral hygiene index (OHI-S). Depression was determined using Beck&rsquo;s depression scale. Pittsburgh Sleep Quality Index (PSQI) was used for scrutinizing sleep quality.</p> <p><strong>Results:</strong> Self‑reported scoring of depression and sleep quality by using Beck&rsquo;s depression inventory and Pittsburgh Sleep Quality Index questionnaire has revealed that patients diagnosed with chronic periodontitis had an appreciable elevated score of depression and poor sleep quality than normal controls.</p> <p><strong>Conclusion:</strong> Findings of this case-control study revealed a statistically significant relationship between depression, its associated oral health behavior, sleep deprivation experienced and severity of destructive periodontal diseases.</p>
Keywords
Periodontal systemic interactions, Clinical depression, Psychological distress, Oral health, Risk factor(s), Pittsburgh Sleep Quality Index, Sleep deprivation
Downloads
  • 1
    FullTextPDF
Article

Introduction

Oral health is an indispensable constituent of an individual’s general health and well-being. Periodontitis is a chronic inflammatory disease that is characterized by episodes of active destruction, marked inflammatory infiltration, loss of attachment, and alveolar bone. The underlying processes responsible for this destruction involve both the direct damage of tissues by noxious bacterial products and indirect damage through bacterial stimulation of various inflammatory and immune responses in the host.1 But recently it has been recognized that there are numerous systemic disorders and certain medications that may affect the periodontal attachment apparatus and result in loss of clinical attachment and alveolar bone level. Even though these disorders are rare or uncommon, they frequently cause major loss of periodontal tissues by influencing periodontal inflammation or by mechanisms different from periodontitis.2 Extraordinary research is therefore being conducted lately to understand the underlying association between periodontal disease and systemic health.3 It has been observed that the pathogenesis of inflammatory periodontal diseases is affected by various factors such as poor oral hygiene, smoking, systemic diseases including diabetes mellitus, cardiovascular diseases,4 and several dimensions of psychosocial distress such as stress, depression, anxiety, life events and poor coping reactions.1 It is a known fact that stress and/or depression significantly impacts the host immune response, and on another side, it also affects a large section of the modern population.4

Depression is a highly prevalent disorder present worldwide and is associated with a significant amount of morbidity and mortality. It is estimated that worldwide, on an average 340 million people suffer from depression at any given time. Based on estimations made by the World Health Organization (WHO), it is accountable for the maximum proportion of burden connected with non-fatal health outcomes and is responsible for about 12% of total years lived with disability.5 It is an intricate and multifactorial disorder with various underlying important genetic and non-genetic contributory factors.6

A strong association has been noticed between various stressful life events and major depressive episodes. It has been observed that chronic stress is directly related to depressive disorders. The neurobiology of both stress and depression is explained by various similar molecular and cellular abnormalities that act together with genetic and environmental factors.7

The biological plausibility for the association between depression and periodontitis is based on the hypothesis that is supported by numerous studies which show the role of depression in modulating the host’s immune response, making the individual more vulnerable to the development of unhealthy conditions and affecting periodontal health.6 Depression can lead to biological changes within the body, including dysregulation of hypothalamic-pituitary-adrenal (HPA) axis. Behavioral changes observed in patients with depression includes poorer oral hygiene, increased smoking, and excessive alcohol consumption. Negligence of oral hygiene can result in plaque and calculus accumulation, which can not only lead to gingivitis but also increases the risk of developing periodontitis.8 Furthermore, causal relationships have been noted between sleep deprivation & severity of periodontitis and between sleep deprivation & mood changes. This concept has been highlighted through various animal models and clinical studies.9

Since numerous studies have reported that psychological state of a person can affect the course of chronic diseases, a clear understanding of the association between psychological factors and pathogenesis of periodontitis is required for appropriate diagnosis and treatment planning of periodontal disease. Therefore, the aim of this questionnaire-based study was to test the hypothesis of correlation between depression rating, sleep quality, and the severity of periodontal diseases.

Materials and Methods

The present study was conducted on 100 subjects who were selected randomly from a larger sample representative of people reporting in the outpatient department of Periodontics of Sri Guru Ram Das Institute of Dental Sciences and Research in Amritsar in the state of Punjab. This study included healthy subjects as controls and subjects with moderate chronic periodontitis as cases. The research protocol was submitted in the beginning to the institutional ethical committee. After ethical approval, all the subjects were verbally informed and written consent was taken from all before their inclusion in the study. A detailed history regarding medical and dental conditions or treatments taken was recorded for each patient.

Selection Criteria

Inclusion criteria

• Healthy subjects as controls

• Patients with moderate chronic periodontitis as cases

• Aged between 25 and 55 years

• Non-smokers

• Co-operative subjects willing to sign the consent form

Exclusion criteria

• Periodontal surgery within the last year

• Scaling and root planing as part of initial periodontal therapy within the past six months

• History of diabetes or other diseases such as hypertension, hyperparathyroidism, osteoporosis, etc

• Current treatment with antibiotics

The participants who fulfilled the inclusion and exclusion criteria were divided into two groups comprising 50 subjects in each group.

Group I (Controls): Fifty systemically and periodontally healthy subjects comprising of 27 females and 23 males.

Group II (Cases): Fifty patients with moderate chronic periodontitis comprising of 28 females and 22 males.

Data Collection

Each participant was given Beck’s depression inventory and Pittsburgh Sleep Quality Index (PSQI) questionnaire to fill, and all the clinical parameters were recorded by a single investigator to eliminate bias.

Clinical Assessment of Depression and Quality of Sleep: Validated questionnaires designed to assist a dental care professional in the determination of depression and quality of sleep and its associated disturbances were used.

Beck’s Depression Inventory: Beck’s depression inventory questionnaire was used for evaluating the scores of depression. It is a self-reported scale that is composed of 21 categories of symptoms and attitudes. Specific behavioral manifestations of depression are described by each category. The ranking of statements was done to reflect the range of severity of the symptoms from neutral to maximal severity. Numerical values ranging from 0-3 were assigned for each statement which is indicative of the increased degree of severity.10 The statements are related to various aspects of behavior such as sadness, pessimism, the feeling of failure, lack of satisfaction, suicidal intentions, irritability, and social withdrawal among others. For the final score of each patient, the greatest value obtained by them for every statement was added up. A cut-off score of 17 or greater was used for identifying the patient with depression symptoms. This scale was also validated in Brazil for estimating the degree of affliction with depression.11

Pittsburgh Sleep Quality Index: The Pittsburgh Sleep Quality Index (PSQI) is a self-rated questionnaire that evaluates the quality of sleep and its associated disturbances. The PSQI was developed to achieve several goals: (1) to provide a consistent, reliable, valid, and standardized measure of evaluating the quality of sleep; (2) able to make a distinction between “good” and “poor” sleepers; (3) to grant an index that is uncomplicated for subjects to make use of and for clinicians and researchers to deduce; and (4) capable of providing in brief, a clinically valuable assessment of a range of sleep disorders that might affect sleep quality. The questionnaire consisted of 19 questions that are to be rated by the patient himself and there were another set of five questions that are rated by their bed partner or roommate. These latter five questions are for the clinical appraisal only and therefore are not to be tabulated in the scoring of the PSQI. The 19 self-rated questions analyze an extensive array of factors concerning sleep quality, including estimates regarding sleep duration and latency and of the frequency and severity of specific sleeprelated problems. These 19 items were further grouped into seven component scores with each being weighted in the same way, on a scale of 0-3. The seven component scores were then added to yield a global PSQI score, which has a range of 0-21; the higher the scores, the worse is the quality of sleep.12

Clinical Parameters Evaluated

Periodontal parameters analyzed in all the subjects included:

1. Probing pocket depth (PPD)

2. Simplified Oral Hygiene Index (OHI-S) (John C. Green and Jack R. Vermillion)13

Statistical Analysis

The recorded data was collected, compiled and put to statistical analysis to arrive at results. The analysis was performed with a statistical software package for social sciences version 17.0 (SPSS, Version 17.0, Inc, Chicago). Student’s t-test unpaired, chi-square test, and Spearman Correlation Coefficient test were used for intergroup comparison between the clinical periodontal parameters and depression.

Results

It was revealed from the present study that mean PD was 2.680 ± 0.683 for the control group as compared 4.620 ± 0.987 for cases which was statistically highly significant at p <0.001. The mean OHI-S recorded for control group was 2.908 ± 0.366 while it was 3.200 ± 1.134 for cases. There was a statistically non-significant difference w.r.t OHI-S between two groups. The mean depression value and mean PSQI score was 12.020 ± 2.945 and 2.680 ± 0.978 respectively for control group, while it was 21.700 ± 6.513 and 7.120 ± 2.520 for cases. Both are statistically highly significant with p <0.001 (Table 1) (Figure 1).

The comparison of the oral hygiene habits between cases and controls was made with the assistance of chi-square test. The percentage of population brushing once daily was observed to be 20% in control group as compared to 60% in cases. 80% of controls were brushing twice daily as compared to 40% of cases. The result was highly significant with p <0.001.

A difference was also seen between the case and control population concerning mouthwash usage. Only 10% of control population reported the habit of not using mouthwash while 12% were using mouthwash once daily. Majority of control population i.e. 78% showed a greater propensity for using mouthwash twice daily, suggesting a positive mindset for daily oral hygiene habits. Among cases, 60% did not report any mouthwash usage, while 26% of cases were using mouthwash once daily. Only a small fraction of patients enrolled as cases (14%) had a habit of using mouthwash twice daily (Table 2). 

Discussion

Periodontal diseases are among the most common oral diseases. There are a variety of risk factors that can influence the initiation, progression, and treatment of periodontal diseases such as smoking, stress, age, the presence of systemic disease, race, ethnicity, and gender.14 Mental health alone may affect oral health, physical health, health behaviors, self-management of disease, medical compliance, social interactions, and quality of life and existence. Coexisting with poor oral health or other chronic conditions, mental health disorders contribute to the severity and progression of the disease and poorer outcomes.15 In this case-control study, the association between psychological and periodontal variables was investigated in a consecutive sample of 100 subjects (Table 3).

OHI(S) – Oral hygiene index (simplified); SD – Standard deviation; PD – Probing depth; PSQI - Pittsburgh Sleep Quality Index

In order to reduce bias, all the patients who were suffering from systemic conditions like diabetes, hypertension, hyperparathyroidism, osteoporosis, etc or with habit of smoking or those taking any such medication that could potentiate the periodontal destruction were excluded from the study.

Correlation between Depression and Periodontal Destruction

The results revealed that higher scores of self-rated Beck’s depression inventory questionnaire in cases were correlated with marked periodontal destruction noticed in them as assessed by PD. The mean PD recorded was greater in cases (4.620 ± 0.987) when compared to the PD recorded in controls (2.680±0.683), suggesting that depression may be the factor present in population enrolled as cases which may be responsible for greater periodontal destruction. Therefore, the correlation between clinical and periodontal parameters as suggested by unpaired t-test justifies the hypothesis of association between depression and greater periodontal destruction.

The results of the present study are in harmony with the studies conducted by Freeman R, Goss S (1993), Linden GJ et al., (1996). Both these studies emphasized the relationship observed between work-related stress and periodontal destructive diseases, reporting significant associations.16 Genco RJ et al., (1999) in a cross-sectional study showed that an increase in CAL was significantly associated with depression. Ng SK et al., (2006) conducted a cross-sectional study establishing that CAL was statistically associated with depression trait. Johannsen et al., (2006 and 2007) conducted case-control studies to show that amount of plaque (p <0.003 and gingival index score (p <0.001) were more in patients with depression when compared to controls, also the patients diagnosed with depression had a significantly higher amount of gingival inflammation (p <0.001), and deeper pockets (p <0.003), when compared to the healthy controls, after adjusting for confounding factors like age and smoking. Rosania AE et al., (2009) reported a correlation between depression and periodontal disease.6

Mechanism of Action

One of the possible reasons for the influence of depression, stress and psychosocial factors on periodontal conditions is the modification of the extension or severity of periodontitis, based on the neuro-immunoendocrine interaction by the action of hormones and other chemical mediators synthesized by the organism in various stressful situations so as to coordinate the fight or flight response.17

Stress perceived by the brain stimulates the hypothalamus to produce a corticotropin-releasing hormone (CRH) which activates the pituitary gland to release adrenocorticotropic hormone (ACTH) after being released into the hypophyseal portal system. This in turn induces the release of corticosteroids from the adrenal cortex. Glucocorticoids, including cortisol (the primary glucocorticoid), exert major suppressive effects through highly specific mechanisms acting at multiple levels which include:

 Reduction in the number of diverse circulating cells including lymphocytes, monocytes, and eosinophils, and inhibition of the accumulation of eosinophils, macrophages, and neutrophils at inflammatory sites.

 At the molecular level, glucocorticoids have been observed to strongly inhibit imperative functions of an array of inflammatory cells including macrophages, neutrophils, eosinophils, and mast cells such as chemotaxis, secretion, and degranulation.

 Inhibition of the cascade of the responses generated by the host’s immune system by inhibiting macrophage

antigen presentation, lymphocyte proliferation, and lymphocyte differentiation to effector cells such as helper lymphocytes, cytotoxic lymphocytes, natural killer cells, and antibody-forming B cells.18

 Glucocorticoids released into the cortex of the suprarenal glands can induce the reduction in the secretion of pro-inflammatory cytokines like interleukins, prostaglandins, and tumor necrosis factor-α.

 Conversely, catecholamines (epinephrine and norepinephrine) produce an opposite effect. They stimulate the production and activity of prostaglandins and several proteolytic enzymes, which can indirectly provoke tissue destruction.6

There may also occur changes in gingival circulation, saliva, or there can be an endocrine imbalance. Xerostomia secondary to antidepressant medication may also play a role in exacerbating periodontitis.19

Effect of Depression on Patients’ Health Behavior

Alternatively, hypothesis from literature suggest that depression may also modify patients’ health behavior. Individuals with high stress levels tend to adopt habits that are harmful to periodontal health, such as negligent oral hygiene, intensification of smoking, or changes in eating habits with negative reflexes to immunological system functions.17

The results from the present study also indicated the considerable differences between cases and controls concerning oral hygiene habits. Through partial correlation analysis (by controlling the effects of variables like age, smoking, systemic conditions) revealed by chi-square tests, and spearman correlation coefficient, an association was noticed between depression and negligence of oral hygiene, thus justifying the hypothesis stating that depression may also modulate patients’ perception regarding maintenance of oral hygiene and health.

These results are in accordance with the study by Anttila S (2006) who investigated the association of dental health behavior and self-perceived dental needs with depression in a population aged 31 years and over. The mild symptoms of depression, female gender, education level of a college degree, and low family earnings were observed to be associated with an inferior frequency of tooth brushing and regularity of dental check-up visits. The study conducted by McFarland ML, Inglehart MR (2010) concluded that the intensity of depression had a substantial impact on overall oral health along with the associated oral health behavior and the depressed patient’s oral health was poorer than the health of non-depressed patients, while the frequency of brushing and flossing the teeth was significantly lower. Park SJ et al., (2014) compared depressed people with a control group and noticed that those with a lifetime diagnosis of depression usually resorted to brushing their teeth once or less in a day (15.8%), had bad self-perceived oral health (52.3%), more toothache (31.5%) and a greater incidence of periodontal bleeding (in both jaws).20

Association Between Depression and Sleep Disorder

It was estimated that up to 90% of those with depression experience sleep disturbances and as such it is a key feature of all diagnostic criteria for depression.21Sleep is an essential biological process that has a substantial role in well-being by activation of body defense mechanisms. It has a critical role in generation of immunological memory and inflammatory homeostatic functions. Sleep problems have emerged as a significant medical and social concern.22 Sleep deprivation has a profound effect on many aspects of physiologic functions such as alertness of mind, memory processing, repair of damaged cells, development of brain, cognition, mood, hormonal regulation, risk of developing depression, increased cortisol, and ghrelin, impaired glucose metabolism, immune system functioning, autonomic activities, increased inflammatory, and proinflammatory markers. Both acute and chronic sleep deprivation may trigger inflammatory processes, leading to an increased concentration of C-reactive proteins (CRP), interleukin-6, and tumor necrosis factor-α along with an increase in the peripheral circulation of leukocytes.23 Due to its potential to influence inflammation and oxidative stress which are the main pathogenetic mechanisms recognized in the periodontal damage, poor sleep quality due to depression could be a factor for periodontitis and poor quality of life.22

Results obtained from this study advocate that sleep disorders are correlated with depression and periodontitis, thus again supporting the hypothesis that depression through various mechanisms intensifies periodontal destruction.

The results are in harmony with the ones obtained from other studies. Grover V et al., (2015) conducted a case-control study that showed a positive association between PSQI, GI, and PPD in patients diagnosed with gingivitis and periodontitis (p <0.05) evaluated with the aid of Pearson coefficient test. Carra MC et al., (2017) conducted a cross sectional study and concluded that the risk of gingival inflammation intensifies in individuals with self-reported sleep disorders. Alqaderi H et al., (2019) in their cross-sectional study concluded that individuals who exhibited severe periodontal disease reported a short sleep duration (less than 7h) with a problem in sleeping. Similar results were found by Saletu A et al., (2005), Singla N (2016), Singh VP et al., (2019), Karaaslan F et al., (2019).24

Lastly, it has also been noticed that the association between periodontal diseases and depression may be bi-directional and periodontal diseases may also contribute in escalating the possibility for developing depression through the accompanying psychosocial effects (e.g., humiliation, seclusion, embarrassment, loneliness) of poor oral hygiene and halitosis, other frequent characteristics observed in the patients diagnosed with periodontal disease. Critically, periodontal diseases are also linked with elevated levels of systemic inflammation, which may heighten inflammatory, oxidative, and nitrosative stress and thus may predispose a patient to depression.9

However, apart from age and smoking, the confounding factors like demographic and socioeconomic characteristics such as education level, patterns of lifestyle, the nutritional status, might have altered the results if taken into consideration and were the limitations of the study. This could have also broadened our horizons by augmenting our knowledge and by providing a better perspective about the pathophysiology of the disease.

Conclusion

In conclusion, the results of the present study clearly revealed the relationship between depression and periodontitis. Therefore, it is suggested that when treating periodontal patients, we should be mindful of factors other than bacterial plaque, such as mental wellbeing, sleep disorders, awareness, and approach towards oral hygiene, to improve patients’ periodontal status. Assessment of depression and associated sleep disorders may be a precious and innovative tool in diagnosis, treatment planning, and maintenance.

Conflicts of interest:

None

Supporting Files
References

1. Halawany H, Abraham N, Jacob V, Al Amri M, Patil S, Anil S. Is psychological stress a possible risk factor for periodontal disease? a systematic review. J Psychiatry 2015;18(1):1-3.

2. Albandar JM, Susin C, Hughes FJ. Manifestations of systemic diseases and conditions that affect the periodontal attachment apparatus: Case definitions and diagnostic considerations. J Clin Periodontol 2018;89(Suppl 1):S183–S203.

3. Garcia RI, Henshaw MM, Krall EA. Relationship between periodontal disease and systemic health. Periodontol 2000 2001;25(1):21-36.

4. Fatima Z, Bey A, Azmi SA, Gupta ND, Khan A. Mental depression as a risk factor for periodontal disease: A case-control study. Eur J Gen Dent 2016;5:86-9.

5. Chiriţă AL, Gheorman V, Bondari D, Rogoveanu I. Current understanding of the neurobiology of major depressive disorder. Rom J Morphol Embryol 2015;56(2 Suppl):651-8.

6. Araújo MM, Martins CC, Costa LC, Cota LO, Faria RL, Cunha FA, et al. Association between depression and periodontitis: a systematic review and metaanalysis. J Clin Periodontol 2016;43(3):216-28.

7. Warren KR, Postolache TT, Groer ME, Pinjari O, Kelly DL, Reynolds MA. Role of chronic stress and depression in periodontal diseases. Periodontol 2000 2014;64(1):127-38.

8. Patel N, Milward M. The oral implications of mental health disorders part 2: depression. Dent Update 2019;46(2):119-24.

9. Dumitrescu AL. Depression and inflammatory periodontal disease considerations-an interdisciplinary approach. Front Psychol 2016;7:347.

10. Beck AT, Ward CH, Mendelson M, Mock J, Erbaugh J. An inventory for measuring depression. Arch Gen Psychiatry 1961;4(6):561-71.

11. Sundararajan S, Muthukumar S, Rao SR. Relationship between depression and chronic periodontitis. J Indian Soc Periodontol 2015;19:294-6.

12. Buysse DJ, Reynolds 3rd CF, Monk TH, Berman SR, Kupfer DJ. The Pittsburgh Sleep Quality Index: A new instrument for psychiatric practice and research. Psychiatry Res 1989;28(2):193-213.

13. Greene JC, Vermillion JR. The Simplified Oral Hygiene Index. J Am Dent Assoc 1964;68:7-13.

14. Sabounchi SS, Torkzaban P, Sabounchi SS, Ahmadi R. Association of oral health behavior-related factors with periodontal health and oral hygiene. Avicenna J Dent Res 2016;8(2):6.

15. Okoro CA, Strine TW, Eke PI, Dhingra SS, Balluz LS. The association between depression and anxiety and use of oral health services and tooth loss. Community Dent Oral Epidemiol 2012;40(2):134- 44.

16. Solis AC, Lotufo RF, Pannuti CM, Brunheiro EC, Marques AH, Lotufo-Neto F. Association of periodontal disease to anxiety and depression symptoms, and psychosocial stress factors. J Clin Periodontol 2004;31(8):633-8.

17. Castro GD, Oppermann RV, Haas AN, Winter R, Alchieri JC. Association between psychosocial factors and periodontitis: a case-control study. J Clin Periodontol 2006;33(2):109-14.

18. Genco RJ, Ho AW, Kopman J, Grossi SG, Dunford RG, Tedesco LA. Models to evaluate the role of stress in periodontal disease. Ann Periodontol 1998;3(1):288-302.

19. Elter JR, White BA, Gaynes BN, Bader JD. Relationship of clinical depression to periodontal treatment outcome. J Periodontol 2002;73(4):441-9.

20. Stepović M, Stajić D, Rajković Z, Maričić M, Sekulić M. Barriers affecting the oral health of people diagnosed with depression: a systematic review. Zdr Varst 2020;59(4):273-280.

21. Paterson LM, Nutt DJ, Wilson SJ. NAPSAQ-1: National Patient Sleep Assessment Questionnaire in depression. Int J Psychiatry Clin Pract 2009;13(1):48- 58.

22. Karaaslan F, Dikilitaş A. The association between stage-grade of periodontitis and sleep quality and oral health-related quality of life. J Periodontol 2019;90(10):1133-1141.

23. Singh VP, Gan JY, Liew WL, Kyaw Soe HH, Nettem S, Nettemu SK. Association between quality of sleep and chronic periodontitis: A case–control study in Malaysian population. Dent Res J 2019;16:29-35.

24. Schmidlin PR, Khademi A, Fakheran O. Association between periodontal disease and non-apnea sleep disorder: a systematic review. Clin Oral Investig 2020;24(10):3335-3345.

We use and utilize cookies and other similar technologies necessary to understand, optimize, and improve visitor's experience in our site. By continuing to use our site you agree to our Cookies, Privacy and Terms of Use Policies.