Inga Harks, Yvonne Jockel-Schneider, Ulrich Schlagenhauf, Theodor W. May, Martina Gravemeier, Karola Prior, Gregor Petersilka, Gregor Ehmke

• Aim This 12-week prospective, randomized, double-blind, two-center trial evaluated the impact of a microcrystalline zinc hydroxyapatite (mHA) dentifrice on plaque formation rate (PFR) in chronic periodontitis patients. We hypothesized that mHA precipitates cause delayed plaque development when compared to a fluoridated control (AmF/SnF\(_{2}\)), and therefore would improve periodontal health. Material & Methods At baseline and after 4 and 12 weeks, PFR and other clinical and microbiological parameters were recorded. Seventy periodontitisAim This 12-week prospective, randomized, double-blind, two-center trial evaluated the impact of a microcrystalline zinc hydroxyapatite (mHA) dentifrice on plaque formation rate (PFR) in chronic periodontitis patients. We hypothesized that mHA precipitates cause delayed plaque development when compared to a fluoridated control (AmF/SnF\(_{2}\)), and therefore would improve periodontal health. Material & Methods At baseline and after 4 and 12 weeks, PFR and other clinical and microbiological parameters were recorded. Seventy periodontitis patients received a mHA or AmF/SnF\(_{2}\) dentifrice as daily oral care without hygiene instructions. Four weeks after baseline, participants received full mouth debridement and continued using the dentifrices for another 8 weeks. Results Primary outcome PFR did not change statistically significantly from baseline to weeks 4 and 12, neither in mHA (n = 33; 51.7±17.2% vs. 48.5±16.65% vs. 48.4±19.9%) nor in AmF/SnF2-group (n = 34; 52.3±17.5% vs. 52.5±21.3% vs. 46.1±21.8%). Secondary clinical parameters such as plaque control record, gingival index, bleeding on probing, and pocket probing depth improved, but between-group differences were not statistically significant. Microbiological analyses showed similar slight decreases in colony-forming units in both groups. Conclusion In patients with mild-to-moderate periodontitis, periodontal therapy and use of a mHA-or AmF/SnF\(_{2}\) dentifrice without instructions induced comparable improvements in periodontal health but did not significantly reduce the PFR.…