Table 1.

Search strategy

PubMed	Embase	Cochrane Library	CNKI	WanFang
Search (((“Periodontitis”[Mesh]) OR (((Periodontitides[Title/Abstract]) OR Pericementitis[Title/Abstract]) OR Pericementitides[Title/Abstract]))) AND ((“Interleukin-13”[Mesh]) OR ((((IL-13[Title/Abstract]) OR Interleukin 13[Title/Abstract]) OR IL 13[Title/Abstract]) OR IL13[Title/Abstract]))	‘periodontitis’/exp. OR ‘periodontitides’:ti,ab OR ‘pericementitis’:ti,ab OR ‘pericementitides’:ti,ab AND (‘interleukin 13’/exp. OR ‘il-13’:ti,ab OR ‘interleukin-13’:ti,ab OR ‘il 13’:ti,ab OR ‘il13’:ti,ab)	#1:MeSH descriptor: [Periodontitis] explode all trees #2:Periodontitides:ti,ab,kw or Pericementitis:ti,ab,kw or Pericementitides:ti,ab,kw (Word variations have been searched) #3: #1 or #2 #4:MeSH descriptor: [Interleukin-13] explode all trees #5: IL-13:ti,ab,kw or Interleukin 13:ti,ab,kw or IL 13:ti,ab,kw or IL13:ti,ab,kw (Word variations have been searched) #6: #4 or #5	Subject = Periodontitis or Topic = Periodontal Disease and Subject = Interleukin 13 or Subject = IL-13 or Subject = IL 13 or Subject = Interleukin-13 (Exact Match)	Subject: (periodontitis + periodontal disease) * Subject: (interleukin 13+ IL-13 + IL 13+ Interleukin-13) *