VNN2 and periodontitis: The positive rates of VNN1 and VNN2 were significantly higher in inflamed gingival tissues than in healthy samples (p < 0.001), as shown in Fig. 4B. The average optical density (AOD) of VNN1 and VNN2 was significantly higher in periodontitis gingival tissues than periodontal healthy samples as well (p < 0.05) (Fig. 4C).