---
title: "Trends in Oral Diseases at a Chinese Level‑II Peacekeeping Hospital in the DRC"
id: "plos-one-21-analysis-of-trends-in-the-spectrum-of-oral-diseases-at-the-chinese-level-ii"
canonical_url: "https://medichelpline.com/clinical-feed/plos-one-21-analysis-of-trends-in-the-spectrum-of-oral-diseases-at-the-chinese-level-ii"
content_type: "clinical_feed_article"
specialty: "Dentistry"
source_name: "PLOS ONE (Medicine)"
source_url: "https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0358265"
published_at: "2026-09-15T14:00:00.000Z"
evidence_level: "Journal Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# Trends in Oral Diseases at a Chinese Level‑II Peacekeeping Hospital in the DRC
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/plos-one-21-analysis-of-trends-in-the-spectrum-of-oral-diseases-at-the-chinese-level-ii
- **Specialty:** [Dentistry](https://medichelpline.com/clinical-feed/dentistry.md)
- **Primary Source:** PLOS ONE (Medicine)
- **Source URL:** [Original Journal Publication](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0358265)
- **Published At:** 2026-09-15T14:00:00.000Z
- **Evidence Rating:** Journal Feed
## Executive GIST (TL;DR)
- This retrospective study analyzed 565 oral outpatient visits to the **Chinese level‑II hospital** serving MONUSCO in the Democratic Republic of the Congo across three deployment batches: Batch 23 (Oct 2019–Sep 2020), Batch 25 (Oct 2021–Sep 2022) and Batch 26 (Oct 2022–Sep 2023). - Oral visits comprised the largest share of specialized outpatient consultations in all three batches: 22.19% (Batch 23), 21.21% (Batch 25) and 25.40% (Batch 26). - Clinical records were complete for the included batches; Batch 24 was excluded due to incomplete records. Repeated visits for the same disease were removed so each observation represents a unique first visit for the diagnosis. - Diagnoses recorded by treating dentists were mapped retrospectively to **ICD‑11** categories by two trained researchers with a third reviewer resolving disagreements. Five categories were used: diseases of hard tissues of teeth; diseases of pulp or periapical tissues; periodontal disease; disorders of oral mucosa; and other oral diseases. - The proportion of **diseases of hard tissues of teeth** increased significantly across batches from 29.27% (Batch 23) to 49.03% (Batch 26) (P for trend < 0.001). **Caries** was the largest contributor and rose from 11.71% to 30.10% (P for trend < 0.001). - Among diseases of pulp or periapical tissues, **pulpitis** was most common; its proportion peaked in Batch 25 (33.12%) and fell to 20.87% in Batch 26 (P = 0.009). - **Periodontal disease** decreased from 15.12% (Batch 23) to 6.80% (Batch 26) (P for trend = 0.008), with Batch 26 significantly lower than Batch 23. - Statistical comparisons used chi‑square and Cochran–Armitage trend tests with Bonferroni correction; analyses were performed in SPSS 25.0 with significance set at P < 0.05. - The study highlights operational implications for dental resource allocation and preparedness in remote peacekeeping settings with limited resupply and local dental infrastructure. - The anonymized dataset supporting the analyses is available as S1 Data accompanying the article. Funding source and competing interest statements were reported in the article.
## Clinical Analysis & Structured Key Points
Analysis of trends in the spectrum of oral diseases at the Chinese level‑II hospital for peacekeeping: A case study from the Democratic Republic of the Congo | PLOS One Browse Subject Areas ? Click through the PLOS taxonomy to find articles in your field. For more information about PLOS Subject Areas, click here . Article Authors Metrics Comments Media Coverage Reader Comments Figures Figures Abstract Background Oral diseases represent an important reason for consultation among personnel attending the Chinese level-II hospital in the Democratic Republic of the Congo (DRC). By analyzing the trends in the spectrum of oral diseases, we aim to improve precision support in oral healthcare for peacekeepers. Materials and methods Clinical data from outpatient visits during Batches 23, 25, and 26 at the hospital were collected. A total of 565 oral outpatient visits (205 in Batch 23, 154 in Batch 25, and 206 in Batch 26) were analyzed. Oral diseases were classified using ICD-11 into five categories, and their proportions and trends were compared using chi‑square tests and Cochran Armitage trend tests with Bonferroni correction. Results Oral outpatient visits accounted for the largest proportion of specialized outpatient consultations across all three batches, accounting for 22.19% (Batch 23), 21.21% (Batch 25), and 25.40% (Batch 26) of all outpatient visits. The proportion of diseases of hard tissues of teeth increased from 29.27% (Batch 23) to 49.03% (Batch 26) ( P for trend < 0.001), and was significantly higher in Batch 26 than in Batches 23 and 25 ( P < 0.001), with caries being the most common. Caries proportion rose from 11.71% (Batch 23) to 30.10% (Batch 26) ( P for trend < 0.001). Among diseases of pulp or periapical tissues, pulpitis was the most prevalent; its proportion peaked in Batch 25 (33.12%) and then significantly decreased in Batch 26 (20.87%, P = 0.009). Periodontal disease declined from 15.12% (Batch 23) to 6.80% (Batch 26) ( P for trend = 0.008), with Batch 26 significantly lower than Batch 23. Conclusion This study provides preliminary insights for oral medical support in peacekeeping missions with similar settings, ensuring effective oral health protection for peacekeepers. Citation: Zhang Y, Niu J, Chen G, Qin D, Li X, Xu L, et al. (2026) Analysis of trends in the spectrum of oral diseases at the Chinese level‑II hospital for peacekeeping: A case study from the Democratic Republic of the Congo. PLoS One 21(9): e0358265. https://doi.org/10.1371/journal.pone.0358265 Editor: Mohmed Isaqali Karobari, University of Puthisastra, CAMBODIA Received: February 12, 2026; Accepted: August 29, 2026; Published: September 15, 2026 Copyright: © 2026 Zhang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: The minimal anonymized dataset underlying the findings of this study is provided as Supporting Information (S1 Dataset) accompanying this article. This dataset contains anonymized, individual level clinical data that were used for the statistical analyses. All directly identifiable information has been removed, and records of repeated visits for the same disease have been excluded to reflect the final analysis cohort. The provided dataset is sufficient to replicate all main results reported in this manuscript. Funding: This work was supported by the Natural Science Foundation of Scientific and Technological Funds for Youth of Gansu (Grant No. 22JR5RA018), awarded to Wei Xue (corresponding author). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The funder’s website is: https://zwfw.gansu.gov.cn/ . Competing interests: The authors have declared that no ompeting interests exist. Introduction MONUSCO, the United Nations Stabilization Mission in the DRC, is authorized to take all necessary means to protect civilians and support peace consolidation efforts in the country [ 1 ]. The Chinese level‑II hospital, subordinate to the MONUSCO Southern Sector, provides medical support to military and civilian peacekeeping personnel from multiple countries [ 2 ]. Its stomatology department is a critical component, staffed by one dentist and one dental assistant in accordance with United Nations level‑II requirements [ 3 ]. In the eastern DRC, access to oral healthcare is extremely limited, and local dental resources are markedly inadequate. Consequently, the local healthcare system cannot provide substantive support to the Chinese level‑II hospital in terms of dental supplies, equipment maintenance, or referral services. This makes it essential for the hospital to rely on its own data to optimize resource allocation and to anticipate the spectrum of oral diseases among the peacekeeping personnel it serves. Oral diseases account for a high proportion among outpatient visits in multiple peacekeeping mission areas [ 4 , 5 ]. Our data reveal that since September 2019, oral outpatient visits at the Chinese level-II hospital have consistently ranked first in number and proportion among all specialized outpatient services, posing a severe threat to the physical health of peacekeepers and presenting significant challenges to oral healthcare delivery at the facility. MONUSCO personnel served by the hospital are deployed within the southern sector. The southern sector’s area of responsibility covers the southern part of South Kivu Province, including Bukavu, Uvira, and surrounding areas. Since 2018, MONUSCO has been gradually withdrawing its forces from the DRC. Consequently, the total number of personnel eligible for care at the Chinese level‑II hospital gradually decreased from approximately 6,000 [ 4 ]. Despite this high burden, there is a lack of longitudinal data on the spectrum of oral diseases and their trends over time in peacekeeping settings. Peacekeepers represent a unique population due to their exposure to high-stress environments, limited access to routine dental care, reliance on the Chinese level-II hospital services, and the logistical challenges of resupplying medical materials in remote mission areas. Existing studies have focused on single time periods, but no study has systematically analyzed how the distribution of oral diseases evolves across consecutive deployment batches in the same mission area. This gap hinders evidence-based allocation of dental supplies and personnel for future rotations. This study aimed to answer the following question: how does the spectrum of oral diseases change across three consecutive batches (Batch 23, Batch 25, and Batch 26) at the Chinese level-II hospital in the DRC. The primary outcomes were the consultation-based proportions of five oral disease categories across the three batches and the trends in selected common diagnoses (caries, pulpitis, periapical periodontitis, and gingivitis). The secondary objective was to derive operational implications for future dental resource allocation in similar peacekeeping settings. Consequently, this study retrospectively summarizes the disease spectrum of patients attending the oral outpatient clinic at the Chinese level-II hospital in the DRC over three batches spanning October 2019 to September 2020 (Batch 23), October 2021 to September 2022 (Batch 25), and October 2022 to September 2023 (Batch 26). It analyzes the types of common and frequently occurring oral diseases in the mission area and their trends in proportions. Given the limited medical supplies in peacekeeping mission areas and the difficulties in replenishing them, this study aims to provide further insights for future peacekeeping medical contingents deployed to Africa or other regions with similar settings to more accurately and reasonably allocate corresponding medical resources. Ultimately, it seeks to enhance the diagnostic and treatment capabilities of oral specialized outpatient services at the Chinese level-II hospital, thereby effectively safeguarding the oral health of personnel in mission areas. Materials and methods Data collection Data were collected from the outpatient case records of the Chinese level-II hospital in the DRC for Batch 23 (covering 1 October 2019–30 September 2020), Batch 25 (covering 1 October 2021–30 September 2022), and Batch 26 (covering 1 October 2022–30 September 2023). All oral outpatient visits during the study periods of these batches were included. Batches 23, 25, and 26 represent all consecutive deployments for which complete and reliable clinical records were available at the time of data collection. Batch 24 was excluded in its entirety due to incomplete records. No missing data were present for the variables analyzed (diagnosis, age, and sex), as all data were extracted from complete clinical records; incomplete batches were excluded entirely rather than imputed. Data for this study were accessed on 10 February 2025 for research purposes. The dataset used for this retrospective analysis was fully de-identified prior to being provided to the research team. The personnel composition includes: (1) Uniformed personnel: peacekeeping troops, military observers, staff officers, and formed police units. (2) Non-uniformed personnel: United Nations civilian personnel within the mission area, composed of non-military and non-police personnel from multiple countries. The hospital does not provide services to the local Congolese population. Exclusion criteria: (1) Batch 24 was excluded in its entirety because its medical records were incomplete. (2) patients who repeatedly visited for the same disease (27 in Batch 23, 30 in Batch 25, and 17 in Batch 26) were excluded after the first visit. For repeated same-disease visits, only the first visit per patient was included; subsequent visits for the same disease were excluded. Data completeness: The final dataset comprises 565 observations (205 from Batch 23, 154 from Batch 25, and 206 from Batch 26), with no missing data for the analyzed variables. The anonymized dataset supporting the findings of this study is available as S1 Data . Data were extracted independently by two trained researchers using a standardized case report form, and discrepancies were resolved by consensus with a third reviewer. No additional instruments or measurement tools were used; all data were derived from routine clinical records. Methods The total number of outpatient cases, the spectrum of oral diseases, and their trends across the three batches were analyzed. (1). Demographic information of patients: gender and age (in years). (2). Classification of oral diseases: Oral diseases were classified into five categories based on the International Classification of Diseases, Eleventh Revision (ICD-11) [ 6 ]. Diagnoses were originally recorded by the attending dentists using clinical terms (e.g., “caries,” “pulpitis”). For this study, two trained researchers retrospectively mapped these clinical diagnoses to the corresponding ICD-11 categories independently. Disagreements were resolved by consensus with a third reviewer. The five categories are: 1) Diseases of hard tissues of teeth, including caries, residual root, residual crown, fracture, dental defect, etc.; 2) Diseases of pulp or periapical tissues, including pulpitis, pulp necrosis, periapical periodontitis, periapical abscess, etc.; 3) Periodontal disease, including periodontitis, periodontal abscess, pericoronitis, pericoronal abscess, gingivitis, etc.; 4) Disorders of oral mucosa, including oral ulcer, oral mucosal infection, etc.; 5) Other oral diseases, including impaction, occlusal interferences, post-extraction complications, etc. The number of cases in each disease category and for each specific diagnosis was calculated. (3). The trends of various diseases and categories across different batches were analyzed. Statistical analysis Data analysis was performed using SPSS 25.0 software. A P value of < 0.05 was considered statistically significant. For measurement data (age), normality of distribution was assessed using the Shapiro‑Wilk test, and homogeneity of variances was assessed using Levene’s test. Since both assumptions were met, pairwise independent-samples t‑tests were performed for age comparisons among the three batches. Measurement data were expressed as mean ± standard deviation (x̅ ± s). Enumeration data included patients’ gender (male/female), the five categories of oral diseases (diseases of hard tissues of teeth, diseases of pulp or periapical tissues, periodontal disease, disorders of oral mucosa, and other oral diseases). These data were expressed as frequencies and percentages, and comparisons between groups were performed using the chi-square ( χ ²) test. The Cochran Armitage test for trend was used to evaluate changes in proportions across the three batches. Results of the Cochran Armitage test are reported as “ P for trend”, while results of the chi‑square test are reported as “ P ”. To adjust for multiple comparisons, Bonferroni correction was applied to all pairwise comparisons, including both age (independent-samples t-tests) and disease proportions (chi-square tests), with statistical significance set at P < 0.0167 (0.05/3). For comparisons that showed statistically significant differences after Bonferroni correction, effect sizes (Cramér’s V) and 95% confidence intervals for the differences in proportions were calculated to quantify the magnitude of the observed differences. Patient and public involvement No patients or members of the public were involved in the design, conduct, reporting, or dissemination plans of this research. Ethics statement This retrospective analysis of anonymized medical records was conducted in accordance with the Declaration of Helsinki. The study protocol was reviewed and granted an exemption from formal ethical approval by the Ethics Committee of the 940th Hospital of Joint Logistic Support Force of Chinese People’s Liberation Army (No reference number was assigned for this exemption). The exemption was granted because the study involved a retrospective analysis of medical records with no interaction with or intervention on human subjects. The data were collected from the Chinese level‑II hospital operating under MONUSCO, and data access and handling complied with the hospital’s data governance policies and relevant UN regulations for medical information within peacekeeping missions. Informed consent was waived because the study involved no more than minimal risk to participants, all data were fully de‑identified prior to analysis, and it was not feasible to obtain consent from all individuals given the retrospective nature and the multinational composition of the patient population. Results Patient demographics and backgrounds at the oral outpatient clinic The demographics of patients attending the general outpatient departments and the oral outpatient clinic at the Chinese level-II hospital across Batches 23, 25, and 26 are shown in Table 1 . There was no statistically significant difference in the age distribution of patients receiving oral outpatient services among Batches 23, 25, and 26 after Bonferroni correction (Batch 23 vs. 25: P = 0.017; Batch 23 vs. 26: P = 0.602; Batch 25 vs. 26: P = 0.074). Notably, the proportion of female patients in the oral outpatient clinic was significantly higher in Batch 25 than in Batches 23 and 26 ( χ 2 = 29.809, P < 0.001). Download: PNG larger image TIFF original image Table 1. Demographics of patients attending the general outpatient departments and the oral outpatient clinic across Batches 23, 25, and 26. https://doi.org/10.1371/journal.pone.0358265.t001 Distribution of disease spectrum among patients of the oral outpatient clinic The detailed distribution of oral diseases across the three batches is presented in Table 2 . Overall, diseases of hard tissues of teeth and diseases of pulp or periapical tissues were the most frequent categories in all batches, while disorders of oral mucosa were the least frequent. Download: PNG larger image TIFF original image Table 2. Distribution of oral diseases among oral outpatient visits across Batches 23, 25, and 26. https://doi.org/10.1371/journal.pone.0358265.t002 Analysis of the trends in disease categories across three batches of the oral outpatient visits The oral outpatient visits in Batches 23, 25, and 26 ranked first in terms of number and proportion among all specialized outpatient consultations, with respective compositions of 22.19%, 21.21%, and 25.40%. The chi-square test showed no significant difference in the proportion of oral outpatient visits among the three batches ( χ ² = 4.298, P = 0.117). The Cochran Armitage test for trend also indicated no significant linear trend across batches ( P for trend = 0.204) ( Table 3 ). The numbers and proportions of different categories of oral diseases across the three batches are shown in Table 4 . Download: PNG larger image TIFF original image Table 3. Trends in the number and proportion of oral outpatient visits across Batches 23, 25, and 26. https://doi.org/10.1371/journal.pone.0358265.t003 Download: PNG larger image TIFF original image Table 4. Trends in the proportion of oral disease categories across Batches 23, 25, and 26. https://doi.org/10.1371/journal.pone.0358265.t004 Regarding cross‑batch comparisons: In Batch 23 and Batch 25, diseases of pulp or periapical tissues had the highest numbers and proportions, whereas in Batch 26, diseases of hard tissues of teeth had the highest numbers and proportions. In all three batches, disorders of oral mucosa had the lowest numbers and proportions. Regarding trend analysis: From Batch 23 to Batches 25 and 26, there was an upward trend in the proportion of diseases of hard tissues of teeth, with a significantly higher proportion in Batch 26 compared to Batches 23 and 25. For example, the proportion was significantly higher in Batch 26 than in Batch 23 ( χ ² = 16.84, P < 0.001; Cramér’s V = 0.20, 95% CI for difference in proportions: 0.11–0.29). Similarly, it was significantly higher than in Batch 25 ( χ ² = 6.48, P = 0.011; Cramér’s V = 0.13, 95% CI for difference: 0.03–0.24). The proportion of diseases of pulp or periapical tissues decreased sequentially across the three batches, but the trend was not statistically significant. The proportion of periodontal disease declined, with the lowest proportion observed in Batch 26, which was significantly lower than that in Batch 23 ( χ ² = 7.31, P = 0.007; Cramér’s V = 0.13, 95% CI for difference in proportions: 0.02–0.14). Analysis of the trends of prevalent oral diseases across three batches By selecting the diseases with the highest frequency in Batch 23, this study analyzed their trends across the three batches, ensuring that at least one disease from each disease category was included in the analysis. Specifically, caries, pulpitis, periapical periodontitis, and gingivitis were selected for further analysis. The trends of these four diseases across the three batches are presented in Table 5 . From Batch 23 to Batches 25 and 26, the proportion of caries showed an upward trend, with a significantly higher proportion in Batch 26 compared to the Batch 23 ( χ ² = 21.44, P < 0.001; Cramér’s V = 0.23, 95% CI for difference in proportions: 0.12–0.25). Pulpitis had the highest proportion in Batch 25 but decreased significantly by Batch 26. The proportion of periapical periodontitis did not show significant changes across the three batches. The proportion of gingivitis showed a decreasing trend, with significantly higher proportions in Batch 23 compared to both Batch 25 ( χ ² = 18.76, P < 0.001; Cramér’s V = 0.23, 95% CI for difference: 0.06–0.14) and Batch 26 ( χ ² = 15.65, P < 0.001; Cramér’s V = 0.20, 95% CI for difference: 0.05–0.13). Download: PNG larger image TIFF original image
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