Dental caries and associated factors among patients visiting Shashamane Comprehensive Specialized Hospital.

INTRODUCTION: Dental caries is a major public health problem. In Ethiopia, prevention and treatment of oral health-related illness had given little attention and there is limited data on the extent and factors associated with oral health-related illnesses and oral care practices.
OBJECTIVE: This study was aimed to investigate the prevalence of dental caries and associated factors among patients visiting Shashamane Comprehensive Specialized Hospital (SCSH).
METHODS: A hospital-based cross-sectional study was conducted among 288 patients who visited SCSH dental clinic from March 1, 2021, to April 15, 2021. A questionnaire was employed to collect the background characteristics of the participants. Dental caries was confirmed as per World Health Organization guidelines. Data were analyzed using SPSS version 24. Bivariable and multivariable logistic regression were used to determine predictors of dental caries. A p-value less than 0.05 was taken as a cut point to determine a significant association.
RESULTS: The overall prevalence of dental caries was 64.6% with 95% CI (58.8‒70.1). The mean of Decayed, Missing, and Filled Teeth was 1.33. Dental caries was significantly higher among respondents who did not brush their teeth (AOR = 3.589, 95% CI:1.756‒7.334), who consumed sugary food (AOR = 3.650, 95% CI: 1.747‒7.628), those with monthly a income of less than 5000.00 Ethiopian Birr (AOR = 2.452, 95% CI (1.193‒5.042), and those who had poor oral hygiene status (AOR = 1.826, 95% CI: 0.901‒3.700).
CONCLUSIONS: This study revealed a high prevalence of dental caries among patients visiting the dental clinic. Tooth brushing habits, consumption of sugary food, and poor oral hygiene were significantly associated with dental caries.

Introduction

The disease of the oral cavity including dental caries is a huge health problem throughout the globe and people of any age can be affected. The oral cavity-related disease can cause pain, discomfort, disfigurement, and sometimes death. Approximately, 3.5 billion people are affected by oral cavity-related diseases [1, 2].

Dental caries develops over time and it has multiple causative agents. Dietary habits, which influence normal flora of the oral cavity, along with host susceptibility is the main factor for dental caries development. Although not often life-threatening, dental caries represents a major public health problem because of its high prevalence and significant impact on general health [3]. Based on the Global Burden of Disease, dental caries (untreated) of permanent teeth is the most predominant condition. About half a billion children are affected by dental caries of milk teeth [4].

There is a piece of evidence to prove the interrelationship between oral and general health [5]. Most systemic diseases such as diabetes and the heart-related problem may have oral signs and symptoms. Even though there is improvement in maintaining oral health worldwide, the problem is still predominant in list-income countries [6]. Dental caries has historically been considered an important component of the global disease burden, which can be effectively prevented and controlled through a combination of community, professional, and individual actions. Early detection of disease in most cases is crucial to control oral-related health problems. Worldwide, the prevalence of dental caries among adults is high as the disease affects nearly 100% of the population in most countries [6].

In Africa, less attention is given to oral health as a result there is limited data in this regard. However, non-communicable diseases, including oral conditions are becoming more prevalent; and there are substantial oral health inequalities in both high and low-income nations across the continent including Ethiopia [7].

Management of oral-cavity-related disease including dental caries is expensive and most of the time it is not considered as part of general health. The cost of dental treatment in most developed countries accounts for about 5% of total health costs [4]. Developing countries are unable to provide services related to oral health diseases. Several factors contribute to oral diseases development which includes consumption of sugary food, smoking cigarette, and consumption of alcohol. The majority of oral diseases can be treated and prevented at early stages [4].

Considering the paucity of literature on dental caries and the public health importance of dental caries, this study is planned to provide some information on the prevalence of dental caries and associated factors among patients attending Shashamane Comprehensive Specialized Hospital (SCSH) dental clinic.

Methods

Study area and design

A hospital-based cross-sectional study was conducted from March 1, 2021, to April 15, 2021, at SCSH Dental Clinic. SCSH provides health care services for over 2 million people. The hospital is located 245 km to the south of Addis Ababa, the capital of Ethiopia, in the West Arsi zone, Oromia regional state. The dental clinic is one of the specialty clinics in the hospital that provides inpatient and outpatient dental services. The average patient flow of the dental clinic per month was 600.

Source population

All patients who attended SCSH dental clinic during the study period were considered as source population whereas all systematically selected patients who visited SCSH dental clinic during the study period were taken as the study population.

Eligibility criteria

All patients who visited the dental clinic and aged greater than one year were included. Patients who were critically sick and unable to communicate were excluded from the study.

Study variables

Dependent variables

Dental caries.

Independent variables

Socio-demographic characteristics: Age, Sex, Educational status, Marital status, Monthly income, Residency.

Dietary habits: Use of sugary foods, Smoking cigarettes, Chewing chat.

Oral hygiene: Tooth brushing habit, Tooth brushing method, Tooth brushing frequency, Fluoride toothpaste usage.

Sample size determination

The sample size was calculated using single population proportion formula with the following assumption, 5% margin of error, 95% Confidence level, 78.2% prevalence of dental caries obtained from a similar study conducted at Debre Tabor General Hospital [8]. After considering 10% for non-response rate the total sample size was 288. Study participants were selected by systematic random sampling technique; with a sampling interval of two until the desired sample size of 288 was reached (Interval size, K = N/n = 600/288 ~ 2).

Data collection

A structured questionnaire modified from the WHO oral health survey [9] was used to collect socio-demographic characteristics, dietary habits, healthcare-seeking behavior towards oral health problems, and factors that affect dental health. Socio-demographic characteristics include age, sex, monthly income, place of residence, educational status, and marital status. Dietary habits and healthcare-seeking behavior include sugary food consumption and dentist visits respectively. Factors that affect dental health include smoking cigarettes, tooth brushing habits, oral hygiene, and chewing of khat.

Physical examination

Each tooth of the individuals was examined for dental caries according to WHO recommendation [10]. Dental probes, dental mirrors, disposable tongue depressors, and flashlights were used to perform the physical examination. Teeth were inspected and probed for the presence of Decay (D), Missing (M), and Filled (F). Clinically, caries was confirmed if a lesion is seen in a pit or fissure, or on the tooth surface, and presence of detectable softened floor, softened wall, or undermined enamel. A filled tooth that contains one or more restorations and one or more areas that are decayed was also included in this category. If any doubt existed, caries was not recorded as present. The tooth was considered as missing because of caries if a person had pain history and/or with cavity before extraction. All clinical observations were recorded on the assessment form.

Data quality control

A questionnaire was originally developed in English and translated to Amharic and Afaan Oromo and translated back to English to confirm its consistency. The pretest was done at Melka oda general hospital, Shashamane, Ethiopia among individuals representing 5% of the total sample size ahead of the study. The aim of the pretest was to check the suitability and consistency of the data collection tool. Training on how to conduct the interview was given for one day for the interviewers. There was regular supervision during data collection. At the end of each working day, completed questionnaires and physical examination forms were checked for completeness and accuracy of the records. The questionnaire was checked for clarity, sensitivity to culture, and the presence of appropriate words to the community. Multicollinearity diagnosis was performed using all indicators to assess the interaction between independent variables.

Data analysis

The completed questionnaire was checked for completeness and consistency of the responses. Then, data were entered to EPI INFO 7and cleaned then analyzed using statistical package for social science (SPSS) version 24. Frequency and percentage were computed using univariate analysis to get summary values. Binary logistic regression was done and variables with a p-value < 0.25 were selected for multivariable analysis. The possibility of multicollinearity was checked before running multivariable logistic regression. Considering all indicators used to diagnose multicollinearity together; variables that had variance inflation factor (VIF) greater than 10 (1/ (1‒R2), tolerance less than 0.1(1‒R2), condition index greater than 50 (or 30), Eigen value less than 0.01, and Proportion of Variation greater than 0.8 (or 0.7) were excluded from multivariate analysis. Factors with a p-value less than 0.25 were analyzed using Multivariable logistic regression to determine predictors of dental caries. Significance was set at p<0.05.

Operational definitions

Dental caries

The presence of tooth decay, missing and filled teeth at the time of oral examination.

Good oral hygiene

If no food particles and no accumulation of dental plaque or calculus are visible on the tooth surface at the time of oral examination.

Poor oral hygiene

If there are food particles in the mouth and there is visible plaque/calculus at the time of oral examination.

Decayed tooth (D)

Includes carious teeth, filled teeth with recurrent decay, a tooth with the only root left, temporarily filled teeth surface with other surfaces (parts) decayed.

Missed tooth (M)

Includes tooth that is missed due to caries but it doesn’t include teeth missing for reasons other than caries.

Filled teeth (F)

Includes teeth that have one or more permanent restoration with no secondary (recurrent) caries [8].

The DMFT index: is the average number of teeth per person that are decayed (D), missed because of caries (M), or filled (F). It is a quantitative expression of the lifetime caries experience of the permanent teeth. In the calculation of the DMFT index, the numerator is the sum total of DMF teeth and the denominator is the total number of persons examined.

Ethical approval and consent to participate

Before initiation of the current study, ethical clearance and permission were obtained from the Institutional Review Board (IRB) of Oromia Health Bureau (Reference number: BEFO/HBTFU/1-16/1078) and SCSH. Written informed consent and assent for participants aged below 18 was obtained before data collection. Written informed consent was also obtained from parents or guardians of children. Any information which indicates the identity of the participants was removed from the data collection tool. All information collected from participants was kept confidential. All procedures were performed in accordance with the Declaration of Helsinki.

Results

Socio-demographic characteristics

From the total of 288 participants, all of them responded making a response rate of 100%. 136 (47.2%) participants were females and nearly two-thirds of the respondents 196 (68.1%) attended formal education. The mean age of the respondent was 31.7 with ±13.4 standard deviations (SD) and 107 (37.2%) of the respondents were in the age group of 20 to 29 years. 197 (68.4%) of the respondents were married. 172 (59.7%) of the respondents had a monthly income of less than 5000.00 Ethiopian birrs (Table 1).

Table 1

Socio-demographic characteristics of patients attending the dental clinic in Shashamane Comprehensive Specialized Hospital, southeast Oromia, Ethiopian, 2021 (N = 288).

Category		Frequency	Percent
Age group in years	<20	39	13.5
	20‒29	107	37.2
	30‒39	74	25.7
	40‒49	32	11.1
	50‒59	21	7.3
	≥60	15	5
Sex	Male	152	52.8
	Female	136	47.2
Educational status	Attended formal education	196	68.1
	Not attended formal education	92	31.9
Residence	Urban	103	35.8
	Rural	185	64.2
Marital status	Married	197	68.4
	Single	78	27.1
	Divorced	13	4.5

Prevalence of dental caries

The overall prevalence of dental caries found in this study was 64.6% with 95% CI (58.8‒70.1). The mean Decayed, Missing, and Filled Teeth (DMFT) were 1.33.

Factors associated with dental caries

The present study revealed a significant association between respondents’ level of education and dental caries (AOR = 0.025, 95% CI: 0.006‒0.095). Dental caries was 3.5 times higher among respondents who did not brush their teeth as compared to those who brushed their teeth (AOR = 3.589, 95% CI: 1.756‒7.334). A participant who consumed sugary foods had a 3.6 times higher chance of having dental caries than those who did not consume sugary foods (AOR = 3.650, 95% CI: 1.747‒7.628). Respondents who had poor oral hygiene status were 1.8 times more likely to be affected by dental caries as compared to those patients whose oral hygiene status was good (AOR = 1.826, 95% CI: 0.901‒3.700). Dental caries was lower among respondents who did not chew khat than those who chew khat (AOR = 0.279, 95% CI: 0.127‒0.611) and dental caries was 2.4 times higher among respondents who earned less than 5000.00 ETB per month as compared to those who earned greater 5000.00 ETB (AOR = 2.452, 95% CI: 1.193‒5.042) (Table 2).

Table 2

Bivariate and multivariable analysis of factors that can predict dental caries among patients attending the dental clinic of Shashamane Comprehensive Specialized Hospital.

Variables	Category	Dental caries (n, %)		COR (95% CI)	p-Value	AOR (95% CI)	p-value
		Yes	No
Educational status	Not attended	89 (96.7)	3(3.3)	0.033(0.010‒108	0.000	0.025 (0.006‒0.095)	<0.001*
	Attended	97(49.5)	99(50.5)	1		1
Khat chewing	Yes	80(79.2)	21(20.8)	0.344(0.196‒602)	0.000	0.279 (0.127‒0.611)	0.001*
	No	106(56.7)	81(43.3)	1		1
Sugary food consumption	Yes	131(76.6)	40(23.4)	3.692(2.223‒.130)	0.000	3.650 (1.747‒7.628)	0.001*
	No	55(47.0)	62(53.0)	1		1
Tooth brushing habit	Yes	56(43.1)	74(56.9)	1		1
	No	130(82.3)	28(17.7)	0.163(0.095‒0.277)	0.000	3.589(1.756‒7.334)	<0.000*
Oral hygiene	Good	40(41.7)	56(58.3)	3.625 (2.185‒6.016)	0.000	1.826 (0.901‒3.700)	0.005*
	Poor	146(76.0)	46(24.0)			1
Monthly Income	<5000.00 ETB	112(67.5)	54(32.5)	1.862 (1.139‒3.043)	0.013	2.452 (1.193‒5.042)	0.015*
	≥5000.00 ETB	74(60.7)	48(39.3)	1
Dentist visit	Yes	117(70.9)	48(29.1)	1.908(1.169‒3.112)	0.010	2.106 (0.891‒4.976)	0.090
	No	69(56.1)	54(43.9)			1
Smoking cigarette	Yes	72(74.2)	25(25.8)	1.945 (1.135‒3.335)	0.016	3.773(0.767‒18.563)	0.102
	No	114(59.7)	77(40.3)	1		1
Residence	Rural	76(75.2)	25(24.8)	0.417(0.242‒0.717)	0.002	0.867 (0.374‒2.012)	0.740
	Urban	110(58.8)	77(41.2)	1		1

*Statistically significant association, ETB: Ethiopian Birr

Discussion

There is limited data on dental caries, especially in Southern parts of Ethiopia. We attempted to assess the prevalence and associated factors of dental caries among patients attending the SCSH dental clinic. This study revealed a high prevalence of dental caries, 64.6%, which is comparable with a cross-sectional study conducted in Turkey (62%) that involved large sample size [11]; however, it is higher than school-based cross-sectional studies conducted in Kenya 37.5% [12], Bahirdar, Ethiopia (21.8%) [13], North West, Ethiopia (36%) [14], and a hospital-based cross-sectional-study conducted in Gondar, Ethiopia (23.64%) [15]. A systematic review and meta-analysis conducted in East Africa (45.7%) [16] and Ethiopia (40.98%) [17] and a school-based cross-sectional study conducted in Shawa, Ethiopia [18] also revealed a low prevalence of dental caries as compared to the current study.

The lowest prevalence of dental caries was reported from Tanzania (8.8%) which is a school-based cross-sectional study) [19], and a high prevalence was reported from Sudan (87.7%) [20]. However, our finding is lower than community-based cross-sectional-study done in Indonesia (82.4%) [21] and a cross-sectional study conducted in Debre Tabor, Ethiopia (78.2%) [8]. The variation observed could be due to the nature of the population studied. For instance, a study conducted in Kenya considered 12 years old children which attended public primary schools [12] whereas a study conducted in Turkey included adults aged 18–74 years that were invited to a dental clinic for free dental examination [11]. A study from Sudan was population-based considered individuals aged ≥16 [20]. As this is a hospital-based study, there might be a high patient flow that could have resulted in a high prevalence of dental caries. The difference with the Kenya and Indonesia studies might be due to heterogeneity of study population and, the socio-demographic differences between those countries.

The MDFT index detected in this study, 1.33, was comparable with a study conducted in North Showa, Ethiopia among school children (1.28±1.21) [18] and a study from Gondar Ethiopia (1.095±0.24) [15]. A systematic review and meta-analysis conducted by Teshome et al. [16] reported a comparable mean of DMFT (1.9441). However, Teshome et al. [16] reported a high mean of DMFT from Sudan (3.146) and Uganda (2.876). The highest mean of DMFT was reported from Sudan (8.7+5.9) [20] and the lowest mean of DMFT was reported from Kenya (0.24) [22]. Countries that reported a higher mean of DMFT might be due to poor oral hygiene practice and regular consumption of sugary foods.

In this study, factors such as educational status, tooth brushing habit, sugary food consumption, khat chewing habit, monthly income, and oral hygiene status showed significant association with the prevalence of dental caries. The higher prevalence of dental caries in those who did not attend formal education than their counterparts could possibly be due to the indirect effect of education on dental caries. Those who attended formal education might have awareness of dental caries and take regular appropriate measures to prevent dental caries. An educated person can read and obtain information about oral health while those who are not educated may not know the cause of dental caries and the measures to be taken for its prevention. Moreover, information related to oral health might be given during formal education. This finding was also supported by similar studies conducted in Gondar, Ethiopia [14, 15] and Turkey [11]. This study revealed a strong positive association between caries development and tooth brushing practice. Participants who did not brush their teeth were 3.5 times at a higher risk of dental caries. A similar finding was reported from Bahirdar, Ethiopia [13] and Indonesia [21]. This could be due to the washing away of sugary food ruminants from the teeth during tooth brushing; therefore, micro-organisms will not get enough time to establish themselves and produce acid which is responsible for caries development [23].

This study showed that patients who did not chew khat had less chance of developing dental caries as compared to those who consumed khat. This could be elaborated as those who chew khat has a tendency to use soft drinks and sugars that help the growth of bacteria on the tooth surfaces. Khat is commonly used in Ethiopia for social and pleasure purposes. Also, certain occupational groups like long-distance truck drivers and students during examination time have a high tendency to consume Khat.

Respondents who had poor oral hygiene status were about 1.8 times more likely to develop dental caries. This finding was in line with a study conducted in south Gondar [8, 15]. Poor oral hygiene increases Streptococcus mutans colonization and in severe cases, the loss of enamel [13]. Poor oral hygiene can lead to the build-up of harmful plaque-forming bacteria that demineralizes teeth enamel and cause dental caries [3]. Respondents who consume sugary foods were 3.65 times at higher risk of dental caries development as compared to those who did not consume sugary foods. This finding was in agreement with the study conducted in Kenya [12, 17]. This might be due to sugary food that facilitates the growth of Streptococcus mutans which can produce acid and lead to the development of dental caries and ultimate tooth decay [24].

Even though statistically not significant, a large proportion of patients who smoke cigarettes had dental caries when compared to those who didn’t smoke cigarettes. This is supported by one study conducted in Portugal, that confirms smoking cigarettes as a risk factor for dental caries [19]. Smoking cigarettes can facilitate bacterial growth and acid production by reducing the buffering capacity of saliva [20].

There was also a significant association between the monthly income of participants and dental caries. Dental caries was 2.452 times higher among respondents who earned less than 5000.00 ETB as compared to those who earned greater than 5000.00 ETB. This finding is in line with the study done in Gondar, Ethiopia [14]. As the income increase, the chance of developing dental caries will decrease. This might be due to study participants with high monthly income are able to buy tooth cleaning materials and visit the dental clinic regularly. The burden of dental caries can be reduced by providing proper health education on how to keep oral hygiene and regular visit to dental clinic.

Limitation of the study

To detect dental caries, we used clinical diagnosis only; it was not supplemented with microbiological methods. The difficulty of radiological examination due to the lack of instruments and laboratory setup might reduce the actual magnitude of the problem. Sweet food items and drinks were assessed by the usual patterns of intake but the amount and the duration of intake were not assessed. The monthly income of participants was assessed by usual estimation as the majority of respondents were from rural areas that have no constant monthly income and this might also hide the true monthly income. The determinant factors were not exhaustive. There could be other determinant factors of dental caries that our study did not address.

Conclusions

The prevalence of dental caries in the current study was high. Educational status, tooth brushing habits, consumption of sugary food, khat chewing, monthly income, and oral hygiene status were significantly associated with the prevalence of dental caries. It is important to provide health education on how to improve horal health in the study area.

2 Feb 2022

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Frédéric Denis, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. You indicated that you had ethical approval for your study. In your Methods section, please ensure you have also stated whether you obtained consent from parents or guardians of the minors included in the study or whether the research ethics committee or IRB specifically waived the need for their consent.

3. Please include additional information regarding the survey or questionnaire used in the study and ensure that you have provided sufficient details that others could replicate the analyses. For instance, if you developed a questionnaire as part of this study and it is not under a copyright more restrictive than CC-BY, please include a copy, in both the original language and English, as Supporting Information

4. Thank you for stating the following financial disclosure:

not applicable

At this time, please address the following queries:

a) Please clarify the sources of funding (financial or material support) for your study. List the grants or organizations that supported your study, including funding received from your institution.

b) State what role the funders took in the study. If the funders had no role in your study, please state: “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.”

c) If any authors received a salary from any of your funders, please state which authors and which funders.

d) If you did not receive any funding for this study, please state: “The authors received no specific funding for this work.”

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

5. Thank you for stating the following in your Competing Interests section:

NO authors have competing interests

Please complete your Competing Interests on the online submission form to state any Competing Interests. If you have no competing interests, please state "The authors have declared that no competing interests exist.", as detailed online in our guide for authors at http://journals.plos.org/plosone/s/submit-now

This information should be included in your cover letter; we will change the online submission form on your behalf.

6. Your ethics statement should only appear in the Methods section of your manuscript. If your ethics statement is written in any section besides the Methods, please move it to the Methods section and delete it from any other section. Please ensure that your ethics statement is included in your manuscript, as the ethics statement entered into the online submission form will not be published alongside your manuscript.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: I Don't Know

Reviewer #2: N/A

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Abstract : within 300 words

Line no 16-17: In Ethiopia, prevention and treatment of oral health-related illness had been given little attention line no 33: This study revealed a high prevalence of dental carries

Line no 36-37: Key words should be arranged alphabetically

Line no 52 and 53: Even though there is improvement in maintaining oral health worldwide, the problem is still predominant in low-income countries. Also reference for this line.

Line no 204-6 : rephrasing required.

Recommended read:

1. Zewdu T, Abu D, Agajie M, Sahilu T. Dental caries and associated factors in Ethiopia: systematic review and meta-analysis. Environ Health Prev Med. 2021 Feb 12;26(1):21. doi: 10.1186/s12199-021-00943-3. PMID: 33579186; PMCID: PMC7881546.

2. Teshome A, Andualem G, Derese K. Dental Caries and Associated Factors Among Patients Attending the University of Gondar Comprehensive Hospital Dental Clinic, North West Ethiopia: A Hospital-Based Cross-Sectional Study. Clin Cosmet Investig Dent. 2020;12:191-198

https://doi.org/10.2147/CCIDE.S247179

3. Anguach Shitie, Rahel Addis, Abebe Tilahun, Wassie Negash, "Prevalence of Dental Caries and Its Associated Factors among Primary School Children in Ethiopia", International Journal of Dentistry, vol. 2021, Article ID 6637196, 7 pages, 2021. https://doi.org/10.1155/2021/6637196

Reviewer #2: Thank you for the manuscript.

First of all, the anonymity of survey data is not mentioned. Also, what steps did the authors took to safeguard the patient identity.

In 104 line it was mentioned that a structured questionnaire was modified from WHO oral health survey. Could you please elaborate on that? Furthermore, the exact questionnaire should be presented in the manuscript.

How many evaluators were there? Were they calibrated?

The uniqueness of the population studied with respect to the other African studies was not discussed in detail. The introduction does not describe in detail the main issue of the paper.

lines 234-239 - there is no literature reference

line 116 - if the tooth was extracted not at the same clinic and the authors did not have any records of that, how did authors determine the reason of tooth extraction?

The authors said that the response rate was 100% and it is hard to believe that all of 288 patients have fully filled the questionnaires.

lines 166 - 167 - the authors should change the words into numbers, there has to be consistency throughout the manuscript.

There cannot be a p value equal to 0.000.

What do the authors consider as a statistically significant result? When COR is <0.05, AOR <0.05 or both?

The discussion section is descriptive, and does not really discuss the results. The results were compared to other studies, however, there were no suggestions how to solve the problems. In the conclusions there are new ideas like integrating promotion of oral health services that has been never mentioned in the discussion, therefore, the conclusions does not really conclude the manuscript. Furthermore, when the results are compared to other studies - where the studies conducted in other countries in the same design? A specification is needed.

The quality of the language could be better. The authors change past and present times a few times throughout the manuscript.

line 43 - develops instead of develop

56 - ‘to’ is missing

69 - keeping in mind - lowercase letter should be changed in to uppercase at the beginning of the sentence

179- index is not a DMF, but DMFT, I would recommend using the newest D3MFT index

183- didn’t into did not

211- MDFT index

Throughout the manuscript different forms of words used - ‘physical examination’ vs ‘intraoral examination’ and they should be unified.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

7 Feb 2022

Response to comments

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

Response: Thank you for the comment; we have checked and corrected according it to the guideline.

2. You indicated that you had ethical approval for your study. In your Methods section, please ensure you have also stated whether you obtained consent from parents or guardians of the minors included in the study or whether the research ethics committee or IRB specifically waived the need for their consent.

Response: We have moved Ethical consideration to Method section. We have also included a statement which indicates about parent or guardian consent for children.

3. Please include additional information regarding the survey or questionnaire used in the study and ensure that you have provided sufficient details that others could replicate the analyses. For instance, if you developed a questionnaire as part of this study and it is not under a copyright more restrictive than CC-BY, please include a copy, in both the original language and English, as Supporting Information

Response: The questionnaire (data collection tool) was adapted with modification from the WHO survey tool as indicated in section ‘data collection’ . We have included the reference for it.

4. Thank you for stating the following financial disclosure:

not applicable

At this time, please address the following queries:

a) Please clarify the sources of funding (financial or material support) for your study. List the grants or organizations that supported your study, including funding received from your institution.

b) State what role the funders took in the study. If the funders had no role in your study, please state: “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.”

c) If any authors received a salary from any of your funders, please state which authors and which funders.

d) If you did not receive any funding for this study, please state: “The authors received no specific funding for this work.”

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

5. Thank you for stating the following in your Competing Interests section:

NO authors have competing interests

Please complete your Competing Interests on the online submission form to state any Competing Interests. If you have no competing interests, please state "The authors have declared that no competing interests exist.", as detailed online in our guide for authors at http://journals.plos.org/plosone/s/submit-now

This information should be included in your cover letter; we will change the online submission form on your behalf.

6. Your ethics statement should only appear in the Methods section of your manuscript. If your ethics statement is written in any section besides the Methods, please move it to the Methods section and delete it from any other section. Please ensure that your ethics statement is included in your manuscript, as the ethics statement entered into the online submission form will not be published alongside your manuscript.

Response: We moved the ethical consideration to the method section as mentioned above.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

________________________________________

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: I Don't Know

Reviewer #2: N/A

________________________________________

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: Yes

Response: We included all the data collected in the result section in the form of tables and text.

________________________________________

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

Response: We have revised the English as shown in the manuscript with track change.

________________________________________

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Abstract : within 300 words

Response: We would like to thank you for thoroughly reviewing the manuscript and giving us valuable comments. The number of words in the abstract is less than 300.

Line no 16-17: In Ethiopia, prevention and treatment of oral health-related illness had been given little attention line no 33: This study revealed a high prevalence of dental carries

Response: The comment is not clear. The statement mentioned in line number 16-17 is for introduction purposes whereas the one mentioned in line number 33 is our finding.

Line no 36-37: Key words should be arranged alphabetically

Response: According to the comment, Keywords are arranged alphabetically as shown in the track change.

Line no 52 and 53: Even though there is improvement in maintaining oral health worldwide, the problem is still predominant in low-income countries. Also reference for this line.

Response: Based on the comment we have added the reference.

Line no 204-6 : rephrasing required.

Response: Thank you for the comment; we rephrased it as shown in the track change.

Recommended read:

1. Zewdu T, Abu D, Agajie M, Sahilu T. Dental caries and associated factors in Ethiopia: systematic review and meta-analysis. Environ Health Prev Med. 2021 Feb 12;26(1):21. doi: 10.1186/s12199-021-00943-3. PMID: 33579186; PMCID: PMC7881546.

2. Teshome A, Andualem G, Derese K. Dental Caries and Associated Factors Among Patients Attending the University of Gondar Comprehensive Hospital Dental Clinic, North West Ethiopia: A Hospital-Based Cross-Sectional Study. Clin Cosmet Investig Dent. 2020;12:191-198

https://doi.org/10.2147/CCIDE.S247179

3. Anguach Shitie, Rahel Addis, Abebe Tilahun, Wassie Negash, "Prevalence of Dental Caries and Its Associated Factors among Primary School Children in Ethiopia", International Journal of Dentistry, vol. 2021, Article ID 6637196, 7 pages, 2021. https://doi.org/10.1155/2021/6637196

Response: Thank you for literatures. We have considered them in the discussion section.

Reviewer #2: Thank you for the manuscript.

First of all, the anonymity of survey data is not mentioned. Also, what steps did the authors took to safeguard the patient identity.

Response: Thank you for the comment, based on the comment we have included the following in ethical consideration section ‘Written informed consent was also obtained from parents or guardians for children participants. Any information which indicates the Identity of the participants was removed from data collection tool. All information collected from participants was kept confidential’

In 104 line it was mentioned that a structured questionnaire was modified from WHO oral health survey. Could you please elaborate on that? Furthermore, the exact questionnaire should be presented in the manuscript.

Response: For the current study we have adapted a survey tool from WHO (we cited it), We have used the adapted questionnaire to collect socio-demographic characteristics, dietary habits, and factors that affect dental health as shown in the track change. It may not be appropriate for the whole survey tool as it is not ours.

How many evaluators were there? Were they calibrated?

Response: This comment is not clear. To confirm dental caries we followed the procedure recommended by WHO as indicated in the manuscript.

The uniqueness of the population studied with respect to the other African studies was not discussed in detail. The introduction does not describe in detail the main issue of the paper.

Response: In the discussion, we have mentioned that the ‘study population’ is one reason for the difference in the finding as shown in the track change.

lines 234-239 - there is no literature reference

Response: The reason we did not include the reference is because it is our comments

line 116 - if the tooth was extracted not at the same clinic and the authors did not have any records of that, how did authors determine the reason of tooth extraction?

Response: We identified by asking past history of participants.

The authors said that the response rate was 100% and it is hard to believe that all of 288 patients have fully filled the questionnaires.

Response: All participants approached agreed to take part in the study.

lines 166 - 167 - the authors should change the words into numbers, there has to be consistency throughout the manuscript.

Response: We have corrected accordingly-changed words into numbers

There cannot be a p value equal to 0.000.

Response: It is the value that SPSS gave us during analysis; we have consulted with the statistician and corrected it as <0.001.

What do the authors consider as a statistically significant result? When COR is <0.05, AOR <0.05 or both?

Response: As indicated in data analysis section, a P-value <0.05 and AOR were considered to determine significant association.

The discussion section is descriptive, and does not really discuss the results. The results were compared to other studies, however, there were no suggestions how to solve the problems. In the conclusions there are new ideas like integrating promotion of oral health services that has been never mentioned in the discussion, therefore, the conclusions does not really conclude the manuscript. Furthermore, when the results are compared to other studies - where the studies conducted in other countries in the same design? A specification is needed.

Response: Based on the comment we have added the following at the end of the discussion ‘The burden of the dental caries can be reduced by providing proper health education on how to keep oral hygiene and regular visit of dental clinic’. We have also included the nature of study (in the discussion section) we have used for comparison as indicated in the manuscript with track change.

-We have removed the content claimed from the conclusion section.

The quality of the language could be better. The authors change past and present times a few times throughout the manuscript.

Response: We have revised and corrected all of them as indicated in the manuscript with track change.

line 43 - develops instead of develop (corrected)

56 - ‘to’ is missing?

69 - keeping in mind - lowercase letter should be changed in to uppercase at the beginning of the sentence (corrected)

179- index is not a DMF, but DMFT, I would recommend using the newest D3MFT index (corrected)

183- didn’t into did not (corrected)

211- MDFT index (corrected)

Throughout the manuscript different forms of words used - ‘physical examination’ vs ‘intraoral examination’ and they should be unified.

Response: We have corrected all of them.

________________________________________

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

Submitted filename: Response to reviewers.docx

Click here for additional data file.

16 Feb 2022

21 Feb 2022

Additional Editor Comments:

Please take into account the comments of reviewer 2 when writing the discussion section.

Response: Thank you for the comment, we have included study design for studies we have used for comparison we have omitted “Khat is commonly used in Ethiopia for social and pleasure purposes. Also, certain occupational groups like long-distance truck drivers and students during examination time have a high tendency to consume Khat.” From the discussion section. In the previous comment we have been asked to provide reference; however, since it is our idea we are unable to provide reference as a result we omitted it.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

________________________________________

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

________________________________________

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: I Don't Know

________________________________________

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: No

________________________________________

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

________________________________________

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: (No Response)

Reviewer #2: Thank you for the correction of the manuscript. However, the Discussion part could be even more improved. Not all of the comments have been addressed properly.

Response: Response: Thank you for the comments; we have included study design for studies we have used for comparison purpose. We have omitted “Khat is commonly used in Ethiopia for social and pleasure purposes. Also, certain occupational groups like long-distance truck drivers and students during examination time have a high tendency to consume Khat.” From the discussion section. In the previous comment we have been asked to provide reference; however, since it is our idea we are unable to provide reference as a result we omitted it. (shown in the manuscript with track change.

Submitted filename: Response to reviewers.docx

Click here for additional data file.

22 Feb 2022

Dental caries and associated factors among patients visiting Shashamane Comprehensive Specialized Hospital

PONE-D-21-30095R2

Dear Dr. Ali,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Frédéric Denis, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

24 Feb 2022

PONE-D-21-30095R2

Dental caries and associated factors among patients visiting Shashamane Comprehensive Specialized Hospital

Dear Dr. Ali:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Frédéric Denis

Academic Editor

PLOS ONE