Table 2 Comparison of study design: Left: Study parameters considered. Top: Included studies. Yes / no: criterion fulfilled / not met

Clinical trial

Yes

Yes

Yes

Yes

Yes

Yes

Randomised, controlled

Yes

Yes

Yes

Yes

Yes

Yes

Chronic periodontitis (CP)

moderate-severe CP + diabetes type2

moderate-severe CP

moderate-severe periodontitis +at least 1 furcation degree 2

severe CP

light, moderate, severe CP

Yes

Gingivitis

No

No

No

No

No

No

Smoker

No

No

Yes (< 10/day)

No

Yes

No

Omega3-fatty acids dosage

1000 mg, 3x/ day for 6 months

300 mg(180 mg EPA, 120 mg DHA), 1x/day for 12 weeks

1000 mg (300 mg DHA+

150 mg EPA) 3x/day for 6 months

900 mg EPA, 900 mg DHA, wheat germ oil

300 mg (each 180 mg EPA+

120 mg DHA)

3x/day

for 12 months

6.25 mg EPA, 19.19 mg DHA 2x/day for 6 months

Aspirin

75 mg, 1x/day for 6 months only test group

No

75 mg 1x /day für 6 months

81 mg 1x /day

No

No

Placebo

Coconut oil for omega-3, lactose for aspirin

300 mg paraffin / day

Yes

Yes

Yes

Yes

Number of patients

40 (20/20)

60 (30/30)

40 (20/20)

80 (40/40)

15 (test 7/control 8)

30 (15/15)

Number of examiners

1

1

1

at least 2 calibrated

> 1 exact specification is missing,calibrated

1

Study period

6 months

3 months

6 months

6 months

12 months

6 months

Oral hygiene instructions

Yes

Yes

Yes

Yes

No

Yes

Subgingival instrumentation

Yes

Yes

Yes

Yes

Yes

Yes

Clinical periodontal parameter

OHIS

GI

Yes

Yes

Yes

Yes

No

Yes

PI

Yes

Yes

Yes

Yes

Yes

Yes

BOP

No

No (only at baseline)

Gingival bleeding index

Yes

Yes

Yes

PD

Yes

Yes

Yes

Yes

Yes

Yes

CAL

Yes

Yes

Yes

Yes

Yes

Yes

Recording of the parameters

0, 3, 6 months

0, 1.5, 3 months

0, 3, 6 months

0, 3, 6 months

0,4,12 months

0,1,3,6 months