Evaluation Of The Efficacy And Safety Of Tooth Bleaching By Nonthermal Atmospheric Pressure Plasma With Saline Solution

Objective: To evaluate the bleaching efficacy and safety of nonthermal atmospheric pressure plasma(NAPP)with saline solution(0.9% NaCl).Methods:Forty extracted human teeth were divided into four groups by completely randomized grouping: Group A(NAPP+saline solution),Group B(cold light+35% hydrogen peroxide gel),Group C(35% hydrogen peroxide gel),and Group D(argon flow+saline solution).Forty Sprague-Dawley(SD)rats were also studied and assigned to Groups A-D in accordance with the same grouping method as previously described.The experimental time for all groups was 20 minutes.The bleaching efficacy of the samples was analyzed by the CIE color system.The surface morphology of the teeth was evaluated by scanning electron microscopy(SEM).The rats were anesthetized,and the upper right first molars were bleached.Two days after the experiment,the rats were euthanized,and the maxillae were processed for pathological analysis.Results:Compared with Group C and Group D,Group A showed greater bleaching efficacy(P<0.05),similar to that of Group B.Compared with Group D,the tooth enamel surfaces in Group B and Group C became rougher,while no clear surface morphology changes were observed in Group A.The dental pulp showed significant pathological changes,such as severe inflammatory infiltrate or necrosis,in Group B and Group C(P<0.05);However,normal pulp issue or mild inflammatory infiltrate were found in most samples after plasma treatment(P<0.05).Conclusion: Nonthermal atmospheric pressure plasma exhibited a similar bleaching efficacy and caused fewer pulp alterations and enamel surface changes compared to bleaching with 35% hydrogen peroxide gel with cold light.