A man complains of gingival pain in his upper left jaw and bleeding that occurs when he brushes his teeth or eats solid food. Objectively on the upper jaw he wears a swaged-soldered metal bridge with 14 and 16 as abutment teeth. The crown edge is pushed under the gingival margin by 0.3 mm. Intermediate part is closely ?tted to the gums. The mucosa is hyperemic, swollen, interdental papillae are smoothed out; touching mucosa with a dental instrument provokes bleeding. What medical tactics should the dentist choose in the first place?