Appendix 1. The Cochrane Library search strategy

#1MeSH descriptor Apicoectomy, this term only in MeSH products
#2MeSH descriptor Root Canal Therapy explode all trees in MeSH products
#3apicect* or apicoect* in All Fields in all products
#4((root next canal next therapy) or (root next canal next filling next material*) or ((root next canal*) near treatment) or ((root next canal*) near filling*) or ((root next canal) near restor*)) in All Fields, from 1800 to 2005 in all products
#5MeSH descriptor Tooth Apex, this term only in MeSH products
#6MeSH descriptor Periapical Diseases explode all trees in MeSH products
#7periapical* or periradicular or peri‐radicular in All Fields in all products
#8endodontic* in All Fields in all products
#9apex or apical* in All Fields in all products
#10MeSH descriptor Retrograde Obturation, this term only in MeSH products
#11((retrograde near fill*) or retrofill* or retro‐fill* or retroseal* or retro‐seal* or (retro* near seal*) or retro‐seal* or ((root next end) near fill*) or (root‐end near fill*) or ((root next end) near seal*) or (root‐end near seal*) or (apical* next seal*) or (apical* near prepar*) or retroprepar* or retro‐prepar* or retrograd* or (reverse near obturat*) or (reverse near fill*)) in All Fields in all products
#12(#1 OR #2 OR #3 OR #4 OR #5 OR #6 OR #7 OR #8 OR #9)
#13(#10 OR #11)
#14(#12 AND #13)