Investigation the effect of wearing N95 respirators during COVID-19 pandemic on salivary PH and flow rate of dentistry stuffs and students of QAZVIN Dental Faculty

doi:10.21203/rs.3.rs-3343888/v1

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Investigation the effect of wearing N95 respirators during COVID-19 pandemic on salivary PH and flow rate of dentistry stuffs and students of QAZVIN Dental Faculty

https://doi.org/10.21203/rs.3.rs-3343888/v1

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Background: Recent pandemic (covid-19) led to wearing face masks for hours a day by healthcare workers. The effect of wearing N95 respirators on salivary pH and flow rate during the COVID-19 pandemic evaluated in this study.

Methods: In this semi-experimental study recruited 100 participants. They asked to use the standard face masks (N95 respirators) for 4 hours and then salivary pH and flow rate was evaluated. Data analysis was done using SPSS software version 23.

Results: There wasn’t a statistically significant difference between mean values of salivary pH and its secretion flow rate before and after mask use with respect to smoking and drinking alcohol status. T Pre- and post-mask analysis demonstrated that the mean salivary pH value differed significantly among participants with positive history of COVID-19, but not the flow rate.

Conclusion: According to the present study, the pH values and salivary flow rate did not change before and after using the face masks, but among the people who had a history of covid-19, the salivary pH value changed.

face mask

N95 respirators

saliva

flow rate

COVID-19

The current study demonstrated that N95 respirator usage has no significant effect on saliva pH and its secretion flow rate
It doesn’t seem that using mask in healthy individuals leads to remarkable side effects.
Instead, life-saving benefits take precedence over minor discomforts.

The outbreak of a novel coronavirus (2018-nCoV) was first reported from Wuhan, Hubei Province, China to World Health Organization (WHO) on December 31, 2019 which causes pneumonia in infected patients. Since then, this emerging respiratory virus has spread around the world and became a pandemic (1). Coronavirus disease 2019 (COVID-19) is a highly contagious and life-threatening infectious disease with unspecific manifestations such as cough, fever, dyspnea and fatigue, and some radiographic findings of pneumonia (2). The severe acute respiratory syndrome coronavirus (SARS-CoV-2), a global pandemic, has exerted an unprecedented pressure on the world-wide healthcare services.

To deal with the adverse effects of the virus, WHO guidelines recommended droplet precautions and the use of Personal Protective Equipment (PPE) (3). The primary way of COVID-19 spread is respiratory droplet transmission which occurs by coughing, sneezing or breathing (4, 5). Facemasks including surgical and N95 masks are key components of PPE for public as well as healthcare workers (HCW), especially when medical workers are dealing with contagious diseases (6).

N95 respirators are one of the most important components of these PPE (3). There is consensus that N95 respirator and filtering face piece 2 (FFP2) provide more efficient protection compared to simple medical or surgical masks for aerosol-generating procedures such as intubation or bronchoscopy. These standard types of respirator are tight seal against the face and minimize the exposure to inhaling the fine particles floating in the air. In addition, these masks must undergo filtration and leakage tests to fulfill the standard requirements. In contrary, the surgical masks are loosely fit and only protect against large droplets and hand-to-face contact (7). The current recommendations for severe acute respiratory syndrome (SARS) and pandemic influenzas are conflicting. For example, WHO recommends the use of surgical mask in low-risk situations and N95 respirators in high-risk situations; however, Centers for Disease Control and Prevention (CDC) recommends wearing N95 mask in both low-risk and high-risk situations (8).

Saliva, the complex biofluid, is produced by three pairs of major salivary glands and hundreds of minor salivary glands, comprising of electrolytes, glycoproteins and enzymes. It lubricates the oral cavity, protects the oral mucosa against various irritations and mechanical injuries, assists in swallowing and digestion, possesses antimicrobial activity and contributes in taste sensation (9, 10). The function of saliva depends on its composition and its secretion flow rate. The saliva pH is regulated by the buffering capacity of salivary flow rate. In low flow rates of salivary secretion, less bicarbonate ions are released, and pH decreases (11); thus, chewing and swallowing occur less efficiently, and the risk of caries and teeth and oral diseases increases (12). Also, low salivary flow rate may result in impaired taste sensation and is usually associated with unpleasant sense of dry mouth called Xerostomia (13).

Some studies have investigated the effects of PPE use on body physiology. T. Montero-Vilchez et al. (14) showed that the skin hemostasis and epidermal barrier function are impaired by wearing face mask and nitrile gloves. P.K. Purushothaman et al. (15) reported that the prolonged use of facemask induces breathing difficulty and causes excessive perioral sweating in HCW and finally leads to the decreased adherence to proper mask wearing and increased risk of infection contraction (15). According to a study conducted by Arin Choudhury et al. (3), wearing N95 respirator for 4 hours causes significant changes in physiologic hemodynamics (heart rate, oxygen saturation and perfusion) and leads to headache, fatigue and breathing difficulty as side effects. Further, Jacek C. Szepietowski et al. (16) reported that many people experience itching and scratch themselves while wearing a mask. Therefore, the mask effectiveness decreases due to improper mask use.

Nevertheless, the body physiologic alterations due to the use of PPE (i.e., N95 masks) are not quite clear (3). Since the investigation over the influence of wearing N95 respirators on oral saliva is limited, this research aimed to study the role of wearing N95 mask on pH and secretion flow rate of saliva.

This semi-experimental study recruited 100 participants (26 clinic personnel and 74 dentistry students) based on convenient sampling from Dentistry School, Qazvin University of Medical Sciences, Qazvin, Iran in 2021–2022. Prior to participant inclusion, this study was approved by ethics committee of Qazvin University of Medical Sciences (Ethics Approval ID: IR.QUMS.REC.1400.337). The inclusion criteria were absence of systemic diseases influencing salivary glands (i.e., diabetes), absence of hypertensive disorders and thyroid diseases, negative history of drugs affecting saliva pH and flow (i.e., anticholinergics, antihypertensive, antidepressant medications), negative history of radiotherapy, absence of intra-oral devices such as orthodontic plaques, and absences of COVID-19 disease at the time of study. Also, the participants should use to wear mask during the day and have the willingness to attend the study. Those participants with poor adherence to wear mask during the day and unwilling to continue the study were excluded.

Data Collection

Using a predesigned checklist, we inquired the information related to demographics, history of systemic diseases and COVID-19, history of malignancy and radiotherapy of head and neck, sensation of dry mouth, history of drugs, smoking and alcohol abuse. The participants were categorized into two groups based on Decayed, Missing, and Filled Teeth index (group 0: DMFT ≤ 3; group 1: DMFT > 3) and also into 4 separate groups according to their Body Mass Index (group 1: BMI < 18.5; group 2: 18.5 < BMI < 24.9; group 3: 25 < BMI < 29.9; group 4: BMI > 30).

The participants provided a saliva sample using the spitting method described by Navazesh at 8 AM. Participation was voluntary and anonymous, after obtaining informed consent. This technique requires the individuals not to drink and eat anything at least 90 minutes prior to saliva sampling. The participants included were asked to collect their saliva in mouth for one minute and then spit it into sterile scaled tube of Falcone, and repeat this technique for 5 consecutive times (total of 5 minutes). The saliva collected was immediately taken to laboratory while maintaining the temperature. The samples were then tested to measure pH and flow rate (ml/min).

Afterwards, the study participants were taught to properly wear N95 respirator for 4 hours and avoid drinking and eating at least 90 minutes before the next saliva sampling. The second saliva sampling was performed at 12 o'clock of the same day with the same method. The salivary pH and flow rate were calculated again and each patients' results were compared with his/her baseline results of morning sampling.

Statistical analysis

Statistical analysis was processed using SPSS software (version 23), and P < 0.05 was considered significant. The continuous, and categorical data were described as the mean ± standard deviation (SD), and the frequency and percentage respectively. Dichotomous variables were compared between the groups using the Chi-square test or Pearson, and continuous variables were analyzed using the independent and paired t test. Continuous variables were analyzed using the independent, one way ANOVA and paired t test.

A total of 119 people were recruited, out of whom 19 were excluded due to not meeting an eligibility criterion and 100 completed the study. The study population included 57% male (57 persons) and 43% female (43 persons). The participants aged averagely 27.81 years (ranged between 20–47 years) and a proportion of 72% were single.

Out of these 100 participants, 12% had history of either smoking or drinking alcohol, 24% had history of COVID-19 infection, 21% had dry mouth, and none history of had systemic disease such as hypertension, diabetes, hyperthyroidism, rheumatoid arthritis, and chemo- and radiotherapy.

According to Tables 1 and 2, there was no significant difference between mean values of salivary pH and its secretion flow rate by comparing the data obtained before and after mask use with respect to smoking and drinking alcohol status(P > 0.005).

Table 1

salivary pH before and after wearing face masks
Table 1		PH before		PH after		P value
Table 1		Mean (ml/min)	SD	Mean (ml/min)	SD	P value
Mask		6.72	.42	6.77	.23	.16
Smoking/ Alcohol	Yes	6.52	.53	6.69	.22	.14
Smoking/ Alcohol	no	6.74	.40	6.78	.23	.37
P value		.09		0.23
Covid-19	Yes	6.52	.48	6.75	.28	.002
Covid-19	No	6.78	.38	6.77	.21	.78
P value		0.007		.68
Xerostomia	Yes	6.56	.28	6.77	.18	.001
Xerostomia	No	6.76	.44	6.77	.24	.86
P value		0.06		0.97
Bmicat	1.00	6.61	.35	6.68	.23	.72
	2.00	6.72	.41	6.77	.24	.15
	3.00	6.76	.52	6.79	.21	.75
	4.00	6.67	.35	6.63	.26	.56
P value		.89		.57
DMFT	1.00	6.67	.41	6.80	.25	.010
DMFT	2.00	6.74	.43	6.75	.22	.871
P value		.46		.25
Sex	Male	6.76	.45	6.77	.24	.80
Sex	female	6.66	.37	6.75	.22	.043
P value		0.22		0.65

Table 2

salivary flow rate before and after wearing face masks
Table 2		Flow rate before		Flow rate after		P value
Table 2		Mean (ml/min)	SD	Mean (ml/min)	SD	P value
Mask		.45	.19	.48	.24	.12
Smoking/ Alcohol	Yes	.44	.15	.42	.20	.68
Smoking/ Alcohol	no	.45	.19	.49	.24	.09
P value		0.80		0.34
Covid-19	Yes	.50	.21	.41	.14	.04
Covid-19	No	.43	.18	.50	.26	.003
P value		.15		.09
Xerostomia	Yes	.46	.15	.42	.10	.26
Xerostomia	No	.45	.19	.50	.26	.03
P value		.70		.05
Bmicat	1.00	.44	.08	.44	.10	1.00
	2.00	.45	.20	.49	.27	.15
	3.00	.46	.16	.47	.15	.82
	4.00	.33	.11	.41	.07	.20
P value		.72		.90
DMFT	1.00	.48	.18	.54	.35	.20
DMFT	2.00	.44	.19	.46	.16	.39
P value		.33		.21
Sex	Male	.48	.19	.46	.20	.67
Sex	female	.41	.17	.50	.28	.009
P value		.11		.42

As shown in Table 1, there is a significant pH difference between participants with positive and negative history of COVID-19 at the beginning of the study -before wearing mask- (P = .009). However, the pH difference was not remarkable after wearing mask in these two groups. Pre- and post-mask analysis demonstrated that the mean pH value differed significantly among participants with positive history of COVID-19 (P = .02), but not the flow rate of salivary secretion (P = .47). In contrast, patients who had no history of COVID-19 infection did not differ considerably before and after wearing mask, neither in terms of pH, nor in salivary flow rate (P > .05).

The pre- and post-mask data analysis also shows that it is only the pH parameter differed significantly among xerostomia participants (P = .01), not the flow rate in the same population (P > .05). Although, the mean flow rate differed significantly between participants with xerostomia and without it after 4-hour period of mask usage (P = .05). Regarding body mass index, neither salivary pH nor its flow rate varied significantly among different categories of BMI (P > .05).

According to Table 2, the difference of salivary pH before and after wearing N95 respirator was significant between participants with DMFT scores ≤ 3 (P = .01). Although, the rate of salivary secretion did not significantly differ in this group of participants by mask usage (P > .05). By the same token, the saliva of participants with DMFT scores > 3 has not been influenced by wearing mask in terms of pH and secretion rate (P > .05).

Regarding gender effect, the pre- and post-mask salivary pH levels was not associated with participants' sex (P > .05); however, the female’s saliva production rate has significantly increased after wearing mask (P = .009). Whereas, the pH and salivary secretion rate were almost the same in males before and after wearing mask (P > .05).

The spread of COVID-19 by droplets via airborne transmission had raised the concern of inevitable social contacts. Hence, the use of different facemask became a trend which each type of facemasks offered various degree of disease prevention. During the pandemic, variety of masks from homemade to FFP2, surgical, and … became accessible to general public (17, 18).

The current study evaluated the effect of wearing N95 respirators on the main parameters of saliva, namely pH and secretion flow rate. According to WHO, N95 respirators also known as P2, KNP95, FFP2 and etc.… are the most standard component of personal protection equipment (PPE) when dealing with respiratory virus infected aerosols (18). In the present study, we investigated the use of N95 mask among high-risk people (i.e., healthcare workers and dentistry students). The literature shows that FFP2 offers a higher filtration capacity and safety against aerosols, compared to surgical and other simple forms of masks. These masks have the least penetration (or leakage) among all types of masks (blockage capacity of ≥ 95%) (18). In order to increase the reliability of study results, various confounding factors such as history of COVID-19 infection, xerostomia, DMFT index and gender were additionally investigated.

The longitudinal analysis of pre- and post-mask data (wearing mask for continuous 4 hours) demonstrated that N95 respirator usage has no significant effect on saliva pH and its secretion flow rate (P > .05). However, Tarabonta et al. (19) reported that people worn FFP2 for 2 hours had less salivary secretion rate than participants without mask, and 3-layer masks did not change any of the saliva parameters. The discrepancies between our findings and those of Tarabonta's study may highlight the differences of study populations (40 vs 10 participants) and the duration of mask usage (4 hours vs 2 hours).

Our results showed that COVID-19 history considerably influences the saliva pH (P = .02), but it does not affect the salivary flow rate after 4-hour-long of N95 respirator usage (P > .05). It should be noted that healthy individuals without history of COVID-19 infection are producing saliva with significantly higher rates after wearing mask for 4 hours, but they are maintaining the post-mask pH parameter almost similar to pH of first saliva sample. This may be due to the fact that COVID-19 infection could influence the quality and quantity of oral saliva (20).

The overall assessment of this study results demonstrates that salivary pH after using N95 mask is not affected by smoking, drinking alcohol, BMI, and participants' sex. In contrary, salivary pH has significantly increased by wearing mask in participants with positive status of xerostomia (P = .001). Further pre- and post-mask pH analysis shows significant difference in participants with DMFT ≤ 3 and no difference among participants with DMFT > 3. On the other hand, the study analyses extended to longitudinal comparison of salivary secretion rate. The only influential factor affecting the salivary flow rate was female gender (P = .009).

Muley-Itke et al. (21) have interpreted the effects of prolonged mask usage as "mask mouth syndrome", and declared that the risk of developing oral or dental diseases increases due to dehydration caused by prolonged wearing of facemask. Examples of such diseases are halitosis, candidiasis, angular cheilitis, tooth decay, and gingivitis. Several studies assessed the adverse effects of wearing facemasks at other diseases' outbreaks (such as influenza pandemic). A meta-analysis conducted by Bakhit et al. (22) in 2020 reported that mask users are commonly complain of discomfort, pressure on nose, difficulty in breathing, headache, dryness of mouth and etc. Such complaints are believed to be in association with the duration of using the mask, and with more intensity while wearing N95 masks (22). Rosner et al. (23) also stated that the problems of using masks in HCW requires further research. There are some other studies that they have investigated the effect of using a mask on the cardiopulmonary system (24, 25).

Nevertheless, the knowledge about the effect of wearing a mask on salivary parameters is scarce. While, any changes in quality and quantity of saliva could potentially predispose the oral soft tissues and teeth to mechanical injuries and variety of diseases.

The saliva samples are adjunct biological fluid used to diagnose and treatment follow-up of various diseases. Given the unique salivary features, saliva contributes a key role in keeping the oral cavity healthy, and many studies and researchers are interested to use saliva in their complementary and noninvasive diagnostic tests (26).

Using salivary specimens for adjuvant diagnostic test are popular due less invasive sampling, lack of need for experienced technicians, and feasibility especially in pediatric cases (26). This technique was also used during COVID-19 pandemic. Uribe-Alvarez et al. (27) reported that decrease of salivary pH can be associated with false positive result of swab tests used for COVID-19 diagnosis.

Nevertheless, it is worthy for medical staff, dentists, surgeons and other HCWs to be familiar with mask-use-related side effects in order to prepare better for possible future pandemics. The HCWs are recommended to reduce these side effects by taking frequent mask-off breaks, drinking water, and hydration, and facemask manufacturers are encouraged to design masks which are more comfortable with high protection (23). According to recent evidences, it does not seem that using mask in healthy individuals (free of any respiratory illness) leads to remarkable side effects. Instead, life-saving benefits of wearing a mask take precedence over minor discomforts (i.e., headache, sensation of dry mouth, …). However, some individuals may experience different psychological issues following a prolonged use of facemasks, but it does not seem directly related to the mask use and psychologic burden of a pandemic is rather a more influential factor (28).

According to the present study, the pH values and salivary flow rate did not change before and after using the face masks, but among the people who had a history of covid-19, the salivary pH value changed.

Acknowledgement (optional)

Statement of Ethics

This study protocol was reviewed and approved by ethics committee of Qazvin University of Medical Sciences, approval number: IR.QUMS.REC.1400.337.

Conflict of Interest Statement

The authors have no conflicts of interest to declare.

Funding Sources

Funding for this study was not received.

Author Contributions

Author MFl, MSs and author MZ designed the experiments. Authors MSs, NL and SBm contributed in data curation; Authors MFl, MSs, NL, SBm and MZ contributed in methodology .Author MM and MZ analyzed the data. Authors MFl, MM and MZ contributed in writing original draft; Authors MSs, LN and SBm contributed in writing review and editing. All authors approved the final version of the manuscript.

Data Availability Statement

The data used to support the findings of this study are included in the article and available on request from Author 1 OR the corresponding author.

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No competing interests reported.

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Investigation the effect of wearing N95 respirators during COVID-19 pandemic on salivary PH and flow rate of dentistry stuffs and students of QAZVIN Dental Faculty

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Abstract

Highlights of the Study

Introduction

Material and methods

Data Collection

Statistical analysis

Results

Discussion

Conclusion

Declarations

References

Additional Declarations

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