Background: Cleft in the lip and/or palate (CLP) is a congenital facial deformity that significantly impacts the oral cavity’s structure and function. This malformation can affect the oral microbiota. The objective of this systematic review was to examine and consolidate the current scientific evidence on the oral microflora in children with CLP. Methods: The search strategy included the PubMed, PubMed Central, Web of Science, Scopus, and Embase databases. The inclusion criteria were studies assessing oral microbiota in children with CLP. The Newcastle–Ottawa Scale (NOS) was used to evaluate the quality of the included studies. Results: The search strategy identified 422 potential articles. Twelve papers met the inclusion criteria. High heterogeneity was observed in methodologies, sample sites, and patient characteristics. Eight studies assessed the levels of Streptococcus mutans and Lactobacillus in saliva, with some reporting significantly higher levels in the cleft group compared to controls, while others found no differences. One study reported a significantly higher colonization rate of Candida species in patients with cleft lip and/or palate. Conclusion: The results of the available studies are unclear. Further research is needed to gain a comprehensive understanding of the oral microbiota and potential implications for oral health management in this population. The review was not registered Registration Statement.

Background/Objectives: Evidence regarding the effect of malocclusion on periodontal health is contradictory. This systematic review with meta-analysis seeks to summarize the available scientific evidence on the relationship between malocclusion and periodontal health in children and adolescents. Methods: A review of four electronic databases (PubMed, Scopus, Embase, and Web of Science) was performed. Observational studies were included if they investigated the link between malocclusion and periodontal health in children and adolescents. The quality of the studies included in the review was determined using the Newcastle–Ottawa Scale (NOS). A meta-analysis was conducted on binary outcomes using random-effect models. The Grading Recommendations Assessment, Development and Evaluation (GRADE) tool was used to determine the certainty of the evidence for each outcome. Results: The initial search yielded 774 potential articles. Nineteen articles were selected for the final qualitative analysis, and four of these were included in the meta-analysis. Certain malocclusion traits appear to be associated with less favorable periodontal health indicators in children and adolescents. Quantitative synthesis restricted to studies using the Gingival Bleeding Index (GBI) suggests that malpositioned teeth, such as crowding or lack of spacing, and Class II or Class III molar relationships may be associated with a higher odds of gingivitis in individuals under 18 years of age. The overall quality of evidence of the studies was very low, according to the GRADE criteria. Conclusions: Observational cross-sectional evidence of very low certainty suggests an association between certain malocclusions (crowding, lack of spacing, Class II or Class III molar relationships) and increased odds of gingivitis in children and adolescents. Evidence regarding dental plaque accumulation is inconsistent and limited by substantial heterogeneity across studies. Causality cannot be inferred, and further high-quality longitudinal studies are required.