Many patients seek orthodontic treatment for esthetic improvement. These patients mostly present with mal-alignment of the anterior teeth. The positive effects of orthodontic treatment on their appearance and self-esteem are easy to envision. However, does orthodontic treatment provide dental health benefits in addition to the esthetic benefits? Do malocclusions harm the periodontium? Is correcting malocclusions with orthodontic treatment beneficial for periodontal health? The purpose of this study is to present evidence available on this topic. Two systematic reviews were conducted to address these questions: does a malocclusion affect periodontal health, and does orthodontic treatment affect periodontal health? Inclusion and exclusion criteria were established for both reviews, and an electronic search and a hand search were conducted. Several papers were included in both reviews, but the overall quality of the studies was weak. The first review found a correlation between the presence of a malocclusion and periodontal disease. Subjects with greater malocclusion have more severe periodontal disease. This may be dependent on oral health status. One should keep in mind that an association does not necessarily mean causation. The second review identified an absence of reliable evidence on the effects of orthodontic treatment on periodontal health. The existing low-quality evidence suggests that orthodontic therapy results in small detrimental effects to the periodontium. The results of both reviews do not warrant recommendation for orthodontic treatment to prevent future periodontal problems, except for specific unusual malocclusions.