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However, there is a lack of studies regarding the influence of seasonality on periodontitis. Therefore, the aim of this non-interventional, retrospective, observational study was to investigate the influence of seasonality on periodontitis.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Materials and methods<\/jats:title>\n                <jats:p>Periodontal parameters of 5,908 patients of a practice-based research network (PBRN) were analysed. Probing pocket depth (PPD), Bleeding on Probing (BOP) and tooth mobility were assessed for seasonal fluctuations.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Results<\/jats:title>\n                <jats:p>Within the PBRN patient data, seasonality was significantly associated with PPD of the individual months in patients with periodontitis. Pairwise comparison between the months showed significantly higher PPD in July compared to several months. PPD appeared significantly lower in December compared to June and November. Regarding season, the proportion of deep PPDs (<jats:inline-formula><jats:tex-math>$$\\:\\ge\\:$$<\/jats:tex-math><\/jats:inline-formula>6\u00a0mm) was significantly higher in summer compared to autumn (<jats:italic>p<\/jats:italic>\u2009=\u20090.024). Concerning BOP, a significant difference between winter and autumn could be observed (<jats:italic>p<\/jats:italic>\u2009=\u20090.016). No seasonal influence was found for tooth mobility.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Conclusion<\/jats:title>\n                <jats:p>This practice-network based study indicated a tendency for seasonal variations in periodontal parameters among periodontal patients. However, the differences did not achieve clinical relevance.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Clinical relevance<\/jats:title>\n                <jats:p>Regarding the seasonality of several diseases there might also be an influence of seasons on the periodontium, which would have a potential influence on periodontal studies and daily periodontal examination.<\/jats:p>\n              <\/jats:sec>","DOI":"10.1007\/s00784-024-05972-0","type":"journal-article","created":{"date-parts":[[2024,10,14]],"date-time":"2024-10-14T08:01:42Z","timestamp":1728892902000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["The seasonal occurrence of periodontitis \u2013 a retrospective cohort study from a practice-based research network"],"prefix":"10.1007","volume":"28","author":[{"given":"Stefanie Anna","family":"Peikert","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephanie","family":"Metzger","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anne Brigitte","family":"Kruse","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Felix","family":"Mittelhamm","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eberhard","family":"Frisch","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kirstin","family":"Vach","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Petra","family":"Ratka-Kr\u00fcger","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Johan Peter","family":"Woelber","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2024,10,14]]},"reference":[{"key":"5972_CR1","doi-asserted-by":"crossref","DOI":"10.1007\/978-3-642-92580-1","volume-title":"Grundri\u00df Der Meteorobiologie Des Menschen - Wetter- Und Jahreszeiteinfl\u00fcsse","author":"BD Rudder","year":"1952","unstructured":"Rudder BD (1952) Grundri\u00df Der Meteorobiologie Des Menschen - Wetter- Und Jahreszeiteinfl\u00fcsse, vol 3. 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It was conducted in accordance with the Helsinki Declaration of 1975, as revised in 2013 []. It was approved by a positive vote by the Ethical Committee of the University Medical Center of Freiburg (EK 493\/16).The postgraduate students of this master\u2019s program in periodontology and implant therapy at the University of Freiburg, Germany, were informed via email in January 2017. Each student was instructed about the design of this study and signed an informed consent form.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval and consent to participate"}},{"value":"Not applicable.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for publication"}},{"value":"The authors declare no competing interests.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"596"}}