Study selection
A comprehensive search yielded 11,148 records, with 11,129 sourced from six electronic databases and an additional 19 identified through reference list examination. After duplicate removal using EndNoteX9 software, 4,763 studies remained for title and abstract screening. Of these, 4,723 studies were excluded due to irrelevance. Subsequently, the full texts of 59 studies, considered potentially relevant, were reviewed, resulting in the inclusion of 19 studies that satisfied the eligibility criteria for the final analysis (Fig. 1).
Flow diagram of the search results using the preferred reporting items for systematic reviews and meta-analysis (PRISMA)
Characteristics of the included studies
A total of 19 cross-sectional studies were included, encompassing 7,747 dental students, with sample sizes in each study ranging from a minimum of 18 to a maximum of 780 participants. The majority of these studies (n = 13) were published between 2013 and 2023. A limited number of studies were conducted in African countries (n = 2), such as Egypt and Tunisia, and in European countries (n = 8), including Turkey, Croatia, Estonia, the Czech Republic, Slovakia, Greece, and Germany. In contrast, the majority of studies (n = 11) were conducted in Asian countries, namely the United Arab Emirates, Malaysia, India, Saudi Arabia, Korea, Japan, Lebanon, and Syria. Additionally, 13 studies surveyed students across all academic years, while a few studies (n = 2) included students during their internship period. Among the included studies, three were multicenter cross-sectional studies. The mean standard deviation of oral health-related HU-DBI total scores of dental students were all reported, of which four studies further reported the mean score and standard deviation for KAB, respectively (Table 1).
Quality appraisal of included studies
Among the 19 cross-sectional studies evaluated, four were deemed to be of high quality, receiving an AHRQ score of 8, while the remaining 15 were classified as medium quality, with scores ranging from 5 to 7. The primary sources of bias identified in these studies were associated with item 8, which failed to describe methods for assessing or controlling confounding factors. In addition, the omission of a rationale for patient exclusion from the analysis in item 7, along with the absence of descriptions pertaining to quality assurance assessments, such as the testing of measurement instruments in item 6, also contributed to the diminished quality of certain studies (Appendix 2).
Results of meta-analysis
The meta-analysis included 19 studies, with 15 reporting dental students’ oral health-related HU-DBI total scores. The heterogeneity results showed HU-DBI total score (Q = 3307.96, I2 = 99.2%, P = 0.000, df = 26), with a large heterogeneity, using a random effects model, meta-analysis results showed that the total mean score of dental students’ oral health was 7.15 (95% CI: 6.82, 7.47) (Fig. 2). Among them, 4 studies reported dental students’ KAB related to oral health. The heterogeneous results showed that knowledge (Q = 650.48, I2 = 99.1%, P = 0.000, df = 6) (Fig. 3), attitudes (Q = 904.33, I2 = 99.3%, P = 0.000, df = 6) (Fig. 4) and behaviors (Q = 123.28, I2 = 95.1%, P = 0.000, df = 6) (Fig. 5), using a random effects model to account for substantial heterogeneity, the meta-analysis results indicated the pooled mean scores of dental students’ KAB concerning oral health were 3,59 (95% CI: 3.21, 3.97), 1.59 (95% CI: 1.23, 1.95), 2.20 (95% CI: 2.07, 2.34), respectively. The pooled mean score for attitudes and behaviors accounted for only about 1/2 of the total score.
Forest plot of the HU-DBI total score of dental students
Forest plot of the oral health-related knowledge of dental students
Forest plot of the oral health-related attitudes of dental students
Forest plot of the oral health-related behaviors of dental students
The results indicated that the oral health-related KAB of dental students was at a medium level, and they had a good grasp of knowledge, but relatively less positive attitudes and behaviors.
Subgroup analyses of oral health-related KAB
To investigate the sources of heterogeneity, subgroup analyses were performed according to regions, gender, academic year, and clinical experience, focusing on the oral health-related HU-DBI total score among dental students. Regarding HU-DBI total score, we found the Europe [7.31 (95% CI: 6.72, 7.90)], female [7.59 (95% CI: 6.93, 8.24)], the sixth year [7.87 (95% CI: 7.15, 8.60)], clinical [7.45 (95% CI: 6.82, 8.09)] dental students had the highest scores. Africa students [6.41 (95% CI: 5.71, 7.12)], male students [7.04 (95% CI: 5.71, 7.12)], the first year students [6.44 (95% CI: 6.14, 6.73)], preclinical students [7.18 (95% CI: 6.36, 8.00)] had the lowest scores.
In subgroup analyses of KAB of dental students related to oral health on the regions, gender, academic year and clinical experience, we found that in terms of knowledge of oral health, Europe [3.95 (95% CI: 3.64, 4.27)], female [3.96 (95% CI: 3.65, 4.28)], the fifth year [3.89 (95% CI: 3.49, 4.29)], clinical [3.99 (95% CI: 3.68, 4.30)] dental students had the highest scores. Africa students [2.89 (95% CI: 2.79, 2.99)], male students [3.93 (95% CI: 3.61, 4.24)], the first year students [3.57 (95% CI: 3.02, 4.12)], preclinical students [3.93 (95% CI: 3.60, 4.26)] had the lowest scores. In terms of attitudes to oral health, Europe [1.87 (95% CI: 1.34, 2.41)], female [1.90 (95% CI: 1.34, 2.46)], the fourth year [1.79 (95% CI: 1.28, 2.30)], clinical [1.90 (95% CI: 1.29, 2.50)] dental students had the highest scores. Asia [1.20 (95% CI: 1.14, 1.25)], male [1.78 (95% CI: 1.31, 2.25)], the first year [1.57 (95% CI: 1.29, 1.84)], preclinical [1.86 (95% CI: 1.36, 2.37)] students had the lowest scores. At oral health behaviors, dental students who were Europe [2.32 (95% CI: 2.24, 2.40)], female [2.35 (95% CI: 2.25, 2.44)], the fifth year [2.36 (95% CI: 2.16, 2.55)], clinical [2.40 (95% CI: 2.34, 2.47)] had the highest scores. Africa students [1.89 (95% CI: 1.83, 1.95)], male students [2.24 (95% CI: 2.15, 2.33)], the first year students [2.13 (95% CI: 1.95, 2.30)], preclinical students [2.22 (95% CI: 2.16, 2.28)] had the lowest scores (Table 2).
Sensitivity analysis
A sensitivity analysis was conducted on the included studies, revealing that none had a significant impact on the meta-analysis results, thereby demonstrating the stability of the survey. Detailed results of the sensitivity analysis are presented in Appendix 3.
Risk of publication bias
The Egger test was employed to assess the publication bias concerning the oral health-related HU-DBI total score among dental students, yielding a p-value of 0.538. Consequently, no significant publication bias was detected (Appendix 4).
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