Table 2 -. List of search parameters used in each database..

Databases	Search parameters
MEDLINE	(wear[tw] OR enamel reduction[tw] OR bolton[tw] OR reproximation[tw] OR reaproximation[tw] OR slenderizing OR tooth wear*[tw] OR tooth wear[MeSH Terms] OR dental wear*[tw] OR dental wear[MeSH Terms] OR tooth attrition[MeSH Terms] OR dental abrasion[MeSH Terms] OR dental abrasion*[tw] OR dental enamel[MeSH Terms] OR dental enamel*[tw] OR non-extraction[tw] OR nonextraction[tw] OR non extraction[tw]) OR (incisor[MeSH Terms] OR incisor*[tw] OR tooth[MeSH Terms] OR tooth[tw] OR teeth[tw] OR tooth extraction*[tw] OR teeth extraction*[tw] OR incisor extraction*[tw] OR extraction*[tw]) AND (tooth crowding[tw] OR tooth crowding[MeSH Terms] OR arch length discrepancy[tw] OR deficiency arch length[tw] OR lower jaw[tw] OR dental irregularity[tw] OR space deficiency[tw] OR lower crowding[tw] OR mandibular crowding[tw] OR incisor crowding[tw] OR crowded[tw]) AND (malocclusion, angle class I[MeSH Terms] OR angle class I[tw]) Filters: ppublication date from 1950/01/01
Scopus	(((ALL(wear) OR ALL(“enamel reduction”) OR ALL(bolton) OR ALL(reproximation) OR ALL(reaproximation) OR ALL(slenderizing) OR ALL(“tooth wear”) OR ALL(“tooth wears”) OR ALL(“dental wear”) OR ALL(“dental wears”) OR ALL(“tooth attrition”) OR ALL(“dental abrasion”) OR ALL(“dental abrasions”) OR ALL(“dental enamel”) OR ALL(“dental enamels”) OR ALL(“non-extraction”) OR ALL(nonextraction) OR ALL(“non extraction”))) OR ((ALL(incisor) OR ALL(incisors) OR ALL(tooth) OR ALL(teeth) OR ALL(“tooth extraction”) OR ALL(“tooth extractions”) OR ALL(“teeth extractions”) OR ALL(“teeth extraction”) OR ALL(“incisor extraction”) OR ALL(“incisor extractions”) OR ALL(extraction) OR ALL(extractions)))) AND ((ALL(“tooth crowding”) OR ALL(“arch length discrepancy”) ORA LL(“deficiency arch length”) OR ALL(“lower jaw”) OR ALL(“dental irregularity”) OR ALL(“space deficiency”) OR ALL(“lower crowding”) OR ALL(“mandibular crowding”) OR ALL(“incisor crowding”) OR ALL(“crowded”))) AND((ALL(“malocclusion angle class I”) OR ALL(“angle class I”) OR ALL(“class I”)))
Web of Science	#1 = TS=(wear) OR TS=(enamel reduction) OR TS=(bolton) OR TS=(reproximation) OR TS=(reaproximation) OR TS=(slenderizing) OR TS=(tooth wear*) OR TS=(dental wear*) OR TS=(tooth attrition) OR TS=(dental abrasion) OR TS=(dental enamel*) OR TS=(non-extraction) OR TS=(non extraction) OR TS=(nonextraction) #2 = TI=(wear) OR TI=(enamel reduction) OR TI=(bolton) OR TI=(reproximation) OR TI=(reaproximation) OR TI=(slenderizing) OR TI=(tooth wear*) OR TI=(dental wear*) OR TI=(tooth attrition) OR TI=(dental abrasion) OR TI=(dental enamel*) OR TI=(non-extraction) OR TI=(non extraction) OR TI=(nonextraction) #3 = TS=(incisor) OR TS=(tooth) OR TS=(teeth) OR TS=(tooth extraction*) OR TS=(teeth extraction*) #4 = TI=(incisor) OR TI=(tooth) OR TI=(teeth) OR TI=(tooth extraction*) OR TI=(teeth extraction*) #5 = TS=(tooth crowding) OR TS=(tooth crowding) OR TS=(arch length discrepancy) OR TS=(deficiency arch length) OR TS=(lower jaw) OR TS=(dental irregularity) OR TS=(space deficiency) OR TS=(lower crowding) OR TS=(mandibular crowding) OR TS=(incisor crowding) OR TS=(crowded) #6 = TI=(tooth crowding) OR TI=(tooth crowding) OR TI=(arch length discrepancy) OR TI=(deficiency arch length) OR TI=(lower jaw) OR TI=(dental irregularity) OR TI=(space deficiency) OR TI=(lower crowding) OR TI=(mandibular crowding) OR TI=(incisor crowding) OR TI=(crowded) #7 TS=(malocclusion angle class I) OR TS=(angle class I) OR TS=(class I) #8 TI=(malocclusion angle class I) OR TI=(angle class I) OR TI=(class I) #1 OR #2 = #9 / #3 OR #4 = #10 / #5 OR #6 = # 11 / #7 OR #8 = #12 / #9 OR #10 = #13 / #13 AND #11 AND #12 Time period covered by searches = 1950-2013