Table 1.

Search strategy, according to each database.

Data Base	Search Strategy
PubMed (MEDLINE)	(orthodontic retainer) AND (((complication OR movement OR post treatment changes OR version) AND (unexpected OR unwanted OR inadvertent)) OR (“orthodontic retainers/adverse effects” (MeSH Terms)) OR (Side effect) OR (Relapse) OR (Torque) OR (twist effect) OR (Active)
The Cochrane Library	(orthodontic retainer) AND (((complication OR movement OR post treatment changes OR version) AND (unexpected OR unwanted OR inadvertent)) OR (adverse event) OR (Side effect) OR (Relapse) OR (Torque) OR (twist effect) OR (Active)
Embase	(orthodontic retainer) AND (((complication OR movement OR post treatment changes OR version) AND (unexpected OR unwanted OR inadvertent)) OR (adverse event) OR (Side effect) OR (Relapse) OR (Torque) OR (twist effect) OR (Active)
Scopus	((orthodontic AND retainer) AND (((complication OR movement OR “post treatment changes” OR version) AND (unexpected OR unwanted OR inadvertent)) OR (“adverse event”) OR (“Side effect”) OR (relapse) OR (torque) OR (“twist effect”) OR (active))