This study aimed to investigate the effects of therapeutic intervention on themorphology of the nail plate and nail bed, as well as the psychological andhand dexterity improvements in adults with damaged nails, nail beds, and bitingbehavior caused by onychophagia. Nail care and artificial nail intervention wereperformed on 14 individuals in their 20s to 50s, who did not have anyorthopedic or dermatological diseases and had not received nail care for 6weeks. The interventions were conducted once every 2 weeks for a total of 3times. To measure the morphological changes of the nail plate and nail bedbefore and after nail care, the length of the nail plate and O'Connor's dexteritywere measured to assess hand function changes. Additionally, the stress levelsbefore and after correction with uBioMacpa were compared within and betweengroups. The significance level was set at 0.05. This study was able to confirmthe correlation between nail care and artificial nail intervention as therapeuticinterventions, and their positive effects on hand dexterity through the recoveryof the nail bed and nail plate.