
Secondary outcomes

calculus, tooth
LITTLE, SECONDARY, PLAQUE
The secondary outcomes assessed the plaque index (PI), calculus index (CI), simplified oral hygiene index (SOHI), and irregularity index (IRI) of the mandibular anterior teeth, and retainers’ failure rate.PI was determined by scoring the buccal, lingual, mesial and distal surfaces of the mandibular anterior teeth from 0 to 3, according to the amount of plaque on each surface.The IRI was determined by using Little’s irregularity index to measure the irregularity of the mandibular anterior teethThe patients were asked to attend the clinic immediately within 24 hours if the retainer was debonded from any tooth or if the retainer was broken. Moreover, the patients were recalled on monthly basis, to check for any broken retainer not perceived by the patient.