OBJECTIVE: To probe into the efficacy of photodynamic therapy combined with minocycline hydrochloride in the treatment of severe periodontitis and its effects on miIR193 a and MCP-1 levels. METHODS: Totally 98 patients with severe periodontitis admitted into Kailuan General Hospital from Jun. 2019 to Jun. 2021 were selected and divided into observation group and control group via random number table

with 49 cases in each group. The control group was treated with minocycline hydrochloride

and the observation group was given photodynamic therapy combined with minocycline hydrochloride. After 4 weeks of treatment

the efficacy and incidences of adverse drug reactions

the periodontal index [plaque index（PLI）

probing depth（PD）

gingival index（GI） and bleeding of probing（BOP）]

masticatory function（masticatory efficiency

bite force）

gingival crevicular fluid inflammation factors [matrix metalloproteinase-7（MMP-7）

monocyte chemoattractant protein-1（MCP-1）

soluble intercellular adhesion molecule-1（sICAM-1）]

micro RNA-193 a（miR-193 a）

bone resorption markers [osteocalcin（BGP）

osteoprotegerin（OPG）

type I collagen cross-linked amino terminal peptide（NTX）]

oral health impact scale 14（OHIP-14） score were compared between two groups. RESULTS: The total effective rate of observation group was 95.92%（47/49）

which was higher than that of the control group（81.63%

40/49）

with statistically significant difference（P<0.05）. After treatment

the GI

PLI

BOP and PD levels of both groups were decreased

and those of the observation group were lower than the control group; the masticatory efficiency and bite force of both groups were increased

and those of the observation group were higher than the control group

with statistically significant differences（P<0.05）. After treatment

the MMP-7

MCP-1

sICAM-1 and NTX levels were decreased

and those of the observation group were lower than the control group; the miR-193 a

BGP and OPG levels were increased

and those of the observation group were higher than the control group

with statistically significant differences（P<0.05）. After treatment

the OHIP-14 scores of both groups were decreased

and that of the observation group was lower than the control group

with statistically significant difference（P<0.05）; the differences in the comparison of incidences of adverse drug reactions including local swelling

local pain and local stimulation were not statistically significant between two groups（P>0.05）. CONCLUSIONS: The efficacy of photodynamic therapy combined with minocycline hydrochloride in the treatment of severe periodontitis is remarkable

which can effectively improve periodontal index

relieve periodontal inflammation and bone resorption

contribute to the promotion of patients’ oral health and chewing function

with high safety.