A comparison of mandibular archwidth changes using two different bracket systems

INTERVENTION: Patients will be randomised into one of the two arms of study. Each arm of study will use a different bracket system, either: 1. Self‐ligating brackets (Damon Q) 2. Non self‐ligating brackets Treatment will then proceed with both bracket systems using the same archwire sequence: 1. 0.014 inch round NiTi archwire 2. 0.014x 0.025 inch Damon Copper NiTi archwire 3. 0.018x 0.025 inch Damon Copper NiTi archwire CONDITION: Orthodontics ? mandibular archform ; Oral Health PRIMARY OUTCOME: Mandibular archwidth changes; 1. Alginate impressions for study models of the maxillary and mandibular arches will be taken at: ; T0: Before placement of fixed appliances, at the start of treatment.; T1: Removal of 0.014 inch round NiTi archwire and placement of 0.014 x 0.025 inch NiTi archwire; T2: Removal of 0.014 x 0.025 inch NiTi archwire and placement of 0.018 x 0.025 inch NiTi archwire ; T3: Removal of 0.018 x 0.025 inch NiTi archwire and placement of next archwire; These study models will be used to measure mandibular archwidth between the 2 groups at T0, T1, T2, and T3 measured at 4 places across arch (c‐c, p1‐p1, p2‐p2, m‐m).; ; 2. Arch width measurements (from study models) ; c‐c: Intercanine width: distance between the mandibular canine tips or between the central fossae on the surfaces in case of worn cusps; p1‐p1: First inter premolar width: distance between the central fossae on the occlusal surfaces of the maxillary first premolars; p2‐p2: Second inter premolar width: distance between the central fossae on occlusal surfaces of the maxillary second premolars; m‐m: Intermolar width: distance between the mesial ends of the central fissures on the occlusal surfaces of the maxillary first molars; ; Measurement for the inter arch distances will be measured in mm using fine‐pointed digital callipers. The measurements will be approximated to the first decimal place. ; ; All measurements will be carried out by a single investigator to avoid inter‐operator error. Intra‐operator reliability will be assessed by repeating measurements on 10 study casts 2 weeks apart and carrying out an error analysis. SECONDARY OUTCOME: 1. Pain perception will be recorded using a pain questionnaire, to be completed by patients following each archwire change at:; 1.1. 2 hrs ; 1.2. 6 hrs ; 1.3. Bedtime on day of appointment ; 1.4. When they wake up the day after their appointment; 1.5. When they wake up 2 days after their appointment; 1.6. When they wake up 3 days after their appointment ; 2. Anxiety experienced will be recorded using an anxiety questionnaire, to be completed by participant at end of appointment; 3. Any appliance breakages during treatment will be recorded INCLUSION CRITERIA: Patients: 1. Aged between 11 and 21 years of age 2. In the permanent dentition 3. Requiring upper and lower fixed appliances 4. Receiving treatment in the lower arch on a non‐extraction basis 5. With mild lower arch crowding 6. All malocclusions