Table 3.

The impact of occurrence of periodontal disease on risk of developing head and neck squamous cell carcinoma.

References	Year	Rated Factor	Type of Study	n	Risk of HNC	Description
Gupta et al. [37].	2020	Periodontitis a—mild b—moderate c—severe	case-control study	212 cases 188 controls	Increased (in the group with periodontitis)	a— OR = 1.92; 95% CI: 0.93—3.96 b— OR = 2.47; 95% CI: 1.29—4.72 c— OR = 2.75; 95% CI: 1.45—5.23
Pereira et al. [36].	2020	Periodontitis (expressed as gingival bleeding)	case-control study	899 cases 899 controls	Increased (in the group with periodontitis)	OR = 2.40 ; 95% CI: 1.40—4.09
Shin et al. [40].	2019	Periodontitis a—incipient b—severe	case-control study	146 cases 278 controls	Increased (in the group with periodontitis)	a—OR = 3.463; 95% CI: 1.348—8.895 b—OR = 4.066; 95% CI: 1.499 –11.026
Khan et al. [41].	2019	Periodontitis	case-control study	276 cases 275 controls	Increased (in the group with periodontitis)	OR = 5.04; 95% CI: 3.18—8.01
Moergel et al. [42].	2013	Periodontitis (expressed as mean bone loss)	case-control study	178 cases 123 controls	Increased (in the group with periodontitis)	OR = 2.4; 95% CI: 1.5—3.8
Zeng XT et al.,[43].	2013	Presence of periodontal disease	meta-analysis		Increased (in the group with periodontitis)	OR = 2.63 95% CI: 1.68–4.14

OR—odds ratio, CI—confidence intervals; HNC—head and neck squamous cell carcinoma.