Defensin-Mediated Oral Immunity: A Systematic Review and Meta-Analysis of DEFB1 Expression in Preventive Dentistry Strategies

Background: Human beta-defensin 1 (DEFB1), together with other defensins, serves as a fundamental immune protector for oral tissues since it suppresses harmful microbial growth and fosters healthy oral conditions. The research included two main purposes assessing the relationship between DEFB1 expression levels and genetic polymorphism with oral disease risks, and evaluating DEFB1's potential for oral disease prevention biomarker use. Methods: This research performed a systematic review and meta-analysis on 11 observational studies using PubMed, Google Scholar, and Web of Science databases. The data extraction process concentrated on recording DEFB1 expression data together with clinical results and population characteristics. The risk-of-bias tools were done using the Newcastle Ottawa tool, while a random-effects model was applied for meta-analysis due to heterogeneity in the studies. Results: Eleven studies that contained DEFB1 gene polymorphisms and expression were considered. Rs11362 and rs1799946 polymorphisms and low levels of DEFB1 gene/protein were linked to increased risks of oral diseases, such as caries and periodontitis. The effect sizes were noted as 2.26 (95% CI: 0.90 -5.67) and -0.59 (95% CI: -1.28 to 0.09). Subgroup and sensitivity analyses showed the same direction of effect. Nonetheless, the significant heterogeneity was recorded (I2 > 90 percent), and the overall certainty of evidence was low because of the study design, inconsistency, and imprecision. Discussion: Research findings show that DEFB1 demonstrates potential as an indicator of susceptibility to diseases, although specific studies exhibit some variation in their results. Additional research needs standardized approaches to advance knowledge.