Evaluation of Clinical and Patient-Reported Outcomes of Laceback

Plaque score

Plaque score will be recorded using Orthodontic Plaque Index (OPI). After removing laceback and archwires, the OPI is scored by blinded clinician after applying plaque disclosing agent on canine, premolar, first molar. Visually examine presence/absence of plaque at tooth surface adjacent to bracket base (mesial, distal, occlusal, gingival), and the condition of the gingival margin. The status is scored according to the criteria below: Score 0 - Brackets are plaque-free Score 1 - Plaque on 1 tooth surface at bracket base Score 2 - Plaque on 2 tooth surfaces at bracket base Score 3 - Plaque on 3 tooth surfaces at bracket base Score 4 - Plaque on 4 tooth surfaces at bracket base and/or gingival inflammation Mean OPI for LB and no LB side is calculated by adding up plaque score of all the teeth recorded on each side, and dividing it by the number of teeth scored. Inter and intrarater reliability testing will be done.

Frequency of archwire complications

For the purpose of this study, archwire complications will include the following: * Archwire fractured at any part distal to the canine bracket - counted as one incident. * Archwire dislodged from one or more canine bracket, premolar bracket, or first molar tube - counted as one incident. * Archwire permanently deformed at any part distal to the canine bracket - counted as one incident. * Any combination of the above three situations - counted as one incident. * Whole archwire lost - counted as one incident each on both LB and no LB sides. Upper and lower archwires will be visually examined when the patient is first seen during the appointment. The number of complications of upper and lower archwires are summed up for each side. Total number of archwire complications throughout study period will be recorded for LB side and no LB side.

Frequency of laceback complications

For the purpose of this study, laceback complications will include the following: * Laceback ligature fractured at any part - counted as one incident. * Laceback ligature dislodged from one or more brackets of canine, premolar, and first molar hook - counted as one incident. * A combination of the above two situations - counted as one incident. * Whole laceback lost - counted as one incident. Upper and lower lacebacks will be visually examined when the patient is first seen during the appointment. The number of complications of upper and lower lacebacks are summed up. Total number of laceback complications throughout study period will be recorded. During emergency appointments, dislodged lacebacks will be retied using the same protocol described previously, whereas broken or missing laceback will be replaced using new but same type of preformed 0.010" stainless steel wire ligature (Ormco Corporation, United States of America) in the same manner.

Pain during orthodontic treatment

Pain on LB and no LB side will be recorded using Visual Analogue Scale (VAS) in a pain diary. Subjects will be reminded via phone to complete the diary at home, and it will be collected back during T1. They will be asked to rate the maximum pain on each side during 4 hr, 24 hr, 3 days, 1 week, 2 weeks, 3 weeks after laceback placement. Subjects will place a mark along a 100 mm horizontal line at the most relevant position, whereby the left extreme indicates "no pain and discomfort" and the right extreme indicates "worst imaginable pain and discomfort". VAS will be measured to the nearest 1 mm using a metal ruler from the low end of the scale to the patient's mark (score 0-100). Each pain score reading will be accompanied by an open-ended question asking what is the cause of pain. Analgesics should not be taken prophylactically - score should reflect maximum pain before analgesics. From the diary, the highest pain score throughout T0-T1 is recorded for LB and no LB side.