... The percentage of participants lost to follow up in the studies ranged from 0% to 38%. Interventions evaluated in the identified studies included: nine studies comparing multi-stranded wire (MSW) versus fibre-reinforced retainers [25,26,28,42,45,46,48,50,52], nine studies comparing different dimensions of wire [12,19,32,36,37,39,41,44,51], six studies comparing direct versus indirect bonding [29-31, 33, 36, 54], three studies comparing different types of composite bonding material [30,47,53], three studies comparing CAD/CAM versus lab made fixed retainers [35,38,49], two studies comparing bonding with liquid resin versus without liquid resin composite [55,57], two studies assessing vacuum formed retainer verses bonded retainers [34,40], and one study comparing light cured and chemical cure composite [43]. ...