Globally, one of the main reasons for visiting a health care facility is dental infection [1,2]. Odontogenic infections can be the result of dental caries, periodontitis, pericoronitis, or complications from dental procedures and can result in the formation of dental abscesses [3]. Both children and adults can be affected by odontogenic infections, and underprivileged groups are especially at risk [4]. Appropriate dental care services are lacking in most low-income countries, and shortages of human resources as well as unmet dental health needs have been reported from Sierra Leone [5,6]. If odontogenic infections are left untreated, dental abscesses can form, which can result in complications such as Ludwig angina, retropharyngeal spread, mediastinitis, necrotizing fasciitis, osteomyelitis, and intracranial abscesses. These complications are associated with high mortality rates [7-10]. The first therapy of choice for abscesses resulting from deep neck space infections (DNSIs) is incision and drainage treatment, and antibiotics are a cornerstone of DNSI treatment [11]. However, due to the inappropriate, widespread use of broad-spectrum antibiotics, pathogens that cause oral infections have become more resistant to antibiotic treatment [12]. A flowchart specifying the criteria for admitting and identifying patients with infections that have a high risk of secondary complications was proposed by one study [13]. Another study developed a risk assessment scale and management algorithm for DNSIs [14]. Although the management algorithm was deemed useful for that particular cohort, which was recruited from a high-income country, it does not seem to be feasible for low- and middle-income country environments where advanced medicotechnological instruments, such as fiberscopes, are not readily available. To the best of our knowledge, up-to-date data on the prevalence, characteristics, and management of complicated dental abscesses in Sierra Leone have not been published yet. As such, our study—the Dental Abscess Study (DELAY)—will prospectively investigate morbidity and mortality from complicated dental abscesses and analyze patients’ characteristics and microbial findings to identify predisposing factors for major complications.

In our study, we hypothesized that extensive odontogenic infections are a frequent and potentially life-threatening clinical problem in Tonkolili Province, Sierra Leone. Current diagnosis, treatment, and outcome management methods require improvement. As such, our study will address the general and specific objectives provided in Textboxes 1 and 2.

The DELAY is a prospective longitudinal cohort study that will be conducted at 2 rural district hospitals in Sierra Leone and will include any cases that are eligible for inclusion, as per the inclusion and exclusion criteria. The study will have a 1-year enrollment period between September 2021 and August 2022. Study participants will routinely be followed up for 3 months.

It is important to indicate that standard local treatment guidelines will be adhered to, regardless of whether patients decide to participate in the DELAY. Given that there will be no interference with the routine treatment modalities, oral consent was considered to be appropriate. That notwithstanding, written informed consent (or thumb-printed consent from illiterate participants) will be documented in a separate form. This consent encompasses consent for the initial examination and all follow-up examinations, including the taking of medical photos. At any point during the study, consent can be withdrawn.

Masanga Hospital is a 120-bed general district hospital that serves a population of around 440,000 people. Masanga is a remote town located in the Kholifa Rowala Chiefdom of the Tonkolili District in Sierra Leone’s Northern Province. The hospital offers inpatient and outpatient services related to internal medicine, pediatrics, surgery, and obstetrics and gynecology and is transitioning from a nongovernmental organization–supported hospital to a fully governmental hospital.

Lion Heart Medical Centre (LHMC) is a 70-bed general district hospital in Yele—a town in the remote south of the Tonkolili District. LHMC serves a catchment population of around 100,000 people who are mainly from the Gbonkolenken, Valunia, and Kamajei chiefdoms. LHMC offers inpatient and outpatient services related to internal medicine, pediatrics, surgery, and obstetrics and gynecology. LHMC too is a nongovernmental organization–supported hospital that is transitioning to become a government-supported hospital in the coming years.

The study population will be selected consecutively from patients who present with complicated odontogenic infection requiring in-hospital admission to 1 of the 2 district hospitals in Tonkolili District—Masanga Hospital or LHMC—from September 4, 2021, to August 31, 2022 (this period is subject to prolongation depending on the number of study participants). Consequently, the study population will most likely consist of, but will not be limited to, Sierra Leone citizens from the Tonkolili District.

In order to be eligible to participate in this study, a patient must meet the following inclusion criteria: (1) the in-hospital admission of any patient due to the clinical suspicion of a complicated odontogenic infection (eg, DNSI, necrotizing fasciitis, cellulitis, dental abscess formation, osteomyelitis, and mediastinitis) and (2) the provision of documented informed consent by a patient or a legal representative.

A potential subject who meets any of the following criteria will be excluded from participating in this study: (1) a swollen neck resulting from any cause other than odontogenic infection (eg, goiters, congenital cysts, and trauma), (2) oral and neck infections resulting from any cause other than odontogenic infection (eg, isolated peritonsillar cellulitis, tonsillitis, isolated osteomyelitis, trauma, or infection after trauma), and (3) the inability of a patient or a legal representative to provide informed consent.

A formal case size calculation has not been conducted, as there is no effect-modifying intervention that can be compared against a therapeutic (clinical) gold standard. The DELAY is an observational study for informing future larger studies on odontogenic infection. We aim to include at least 300 patients from both locations combined. However, we propose the inclusion of 350 patients in the study to account for possible missing data and losses to follow-up.

On admission, study information will be provided to individuals (or their primary caretakers) who are apparently eligible for inclusion, and informed consent will be sought. Subjects who consent and are found to be eligible after checking the inclusion and exclusion criteria will be assigned unique participant identification numbers (PINs). In Masanga Hospital (in the village of Masanga), the first patient will be assigned the PIN “M001,” the second patient will be assigned the PIN “M002,” and so forth. In LHMC (in the town of Yele), the first patient will be assigned the PIN “Y001,” the second patient will be assigned the PIN “Y002,” and so forth.

After PIN assignment, a standardized questionnaire will be completed. The questionnaire contains questions about patients’ characteristics (eg, age, sex, past medical history, and socioeconomic status), clinical symptoms (eg, the start and duration of complaints), and health behaviors (eg, consultation with a traditional healer and dental care). A physical extraoral and intraoral examination will be performed at and during admission and at discharge. These will include measurements of the interlobar distance [15], Adam distance [16], and interincisal distance at maximal mouth opening [16,17] (Table 1).

Details on the clinical conditions of patients upon admission (eg, vital signs, airway patency, and AVPU [Alert, Responsive to Verbal Stimulus, Responsive to Pain Stimulus, Unresponsive] scale scores), as well as suspected complications (eg, sepsis, cervical necrotizing fasciitis, and mediastinitis), will be noted. If a patient has provided consent, a medical photo will be taken. Standard laboratory testing will be conducted depending on the availability at the study site and will include hemoglobin tests (Masanga and Yele), white blood cell count tests (Masanga and Yele), malaria rapid testing, hepatitis B surface antigen tests, and HIV testing (Masanga and Yele).

If applicable, a pus swab will be taken and sent to the laboratory at the University Hospital of Münster, Germany, for culture and bacterial cell count tests as well as antibiotic susceptibility testing. Moreover, a pure pus sample will be taken and stored locally in a freezer. A bacteriology lab is under construction at the Masanga site—a development that has been delayed due to COVID-19 epidemic circumstances. Provided that the on-site bacteriology laboratory becomes operational during the study period, which is likely to be the case, the samples will be tested there, and the results will be validated at the Münster collaboration site. If blood culture material becomes available at the local level during the study period, blood cultures will be collected. Treatment will be provided in accordance with standard local treatment guidelines; we will not wait for antibiotic susceptibility results before the start of antibiotic therapy, given the long shipping times. As the local laboratory will most likely not be certified during the study periods, and as the results from the Münster reference laboratory will only become available after an individual patient’s acute treatment period, laboratory results will not be used to modify treatment.

Data on treatment will be collected on the date of admission (eg, the use of antibiotics and planned surgeries) and on the day(s) of surgery (ie, if a surgery will be performed). Additionally, several outcome parameters will be measured on the day of admission; on postoperative days 1, 2, and 7 (in cases where surgery has been performed); on discharge; and at both routine follow-up visits. These will include the interlobar distance, the maximal interincisal mouth opening capacity, and the Adam distance. On discharge, additional data on outcomes will be collected (eg, the state of wound closure, the presence of facialis paresis, and mortality), and medical photos will be taken.

Follow-up visits will take place on postdischarge weeks 4 and 12. If necessary, additional follow-up visits will be conducted. A standardized questionnaire regarding current symptoms will be taken at follow-up visits, during which a physical examination will be performed and a photo will be taken.

Further specifics on which parameters will be recorded during admission, discharge, and follow-up can be found on the case record form in this study protocol (Multimedia Appendix 1).

Paper versions of the informed consent forms will be filled out and stored on-site upon admission. Data will be collected and stored on-site on paper case record forms by trained research staff. During the data collection phase of the study, all variables will be entered on a research computer by using Microsoft Access at each separate study site (offline database). Data will be double entered by 2 different researchers on 2 separate forms and subsequently matched to identify errors.

All medical photos taken during the study will be encoded by using the following file name format: “PIN_contact moment.” In the contact moment field, 1 of 4 labels will be used, as follows: “A” (admission), “D” (discharge), “F1” (follow-up visit 1 after 1 month), and “F2” (follow-up visit 2 after 3 months). An example file name of a photo that is taken upon the admission of a theoretical study participant in the Masanga study site would be “M005_A.png.” Medical photos will be stored on a hard drive during the data collection period. After the study period, all study data will be stored for a minimum of 15 years in 1 database at the Masanga Medical Research Unit (MMRU).

Microsoft Excel and SPSS (IBM Corporation) will be used for the analysis of the data. An exploratory analysis of the variables and descriptive statistics of the data will be carried out. Study parameters will be assessed from an etiologic perspective. For data consistency, certain groups might be excluded from the data analysis (eg, neonates). The description of the distribution of each variable will be made based on measures of central tendency (mode, mean, and median) and measures of dispersion (variance, SD, and maximum and minimum values). Pearson chi-square tests and Kaplan-Meier curves will be used to analyze the study objectives. Logistic regression analyses as well as Cox regression models will be conducted to assess the predictive value of patients’ characteristics and microbial findings on outcomes.

Patients will be approached by the researchers after admission to the hospital and will be asked to provide informed consent after they have received and studied the patient information (Multimedia Appendix 2). This consent will include permission to publish anonymized (nonidentifiable) picture material. Since treatment will be performed according to the local guidelines, participation in the study will not influence the treatment that patients receive. Informed consent files (Multimedia Appendix 3) will be kept at the MMRU and at LHMC, as will the patient-reported questionnaires. Study participants can leave the study at any time for any reason if they wish to do so, without any negative consequences for the care provided. The investigator can decide to withdraw a participant from the study for urgent medical reasons.

The study was scientifically scrutinized and endorsed by the MMRU’s Scientific Review Board on June 16, 2021, and was granted scientific and ethical clearance by the Sierra Leone Ethics and Scientific Review Committee, Freetown, on July 5, 2021.

Major contributions (salaries, accommodations, and consumables related to routine care) will be made as in-kind contributions by the participating centers. In August 2021, Dental Health International Netherlands approved the funding of the budgeted costs of the study (Table 2) after endorsing the study protocol. The Center of Tropical Medicine and Travel Medicine (of whom MPG is the head) serves as a sponsor of the study and serves as the guarantor for the funding (up to the sum described in the budget; Table 2), so that the study can be initiated right after approval.

The projected start date of data collection was September 4, 2021, and data collection is expected to be complete in November 2022. A timeline is presented in Table 3.

Study results will be reported in accordance with the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines [18] for the reporting of prospective cohort studies. Study results are planned to be presented at the community level and during scientific meetings. One or several papers intended for publication in peer-reviewed journals will be prepared timely.