Evaluation of Clinical and Patient-Reported Outcomes of Laceback

Aim:

To evaluate the clinical and patient-reported outcomes of laceback usage during alignment phase of orthodontic fixed appliance treatment.

Specific Objectives:

1. To assess the effect of laceback on patient's oral hygiene during alignment phase of orthodontic fixed appliance treatment. 2. To investigate the effect of laceback on the frequency of archwire complications during alignment phase of orthodontic fixed appliance treatment. 3. To determine the frequency of laceback complications during alignment phase of orthodontic fixed appliance treatment. 4. To study the effect of laceback on pain during alignment phase of orthodontic fixed appliance treatment.

Research questions:

1. What is the effect of laceback on patient's oral hygiene during alignment phase of orthodontic fixed appliance treatment? 2. What is the effect of laceback on the frequency of archwire complications during alignment phase of orthodontic fixed appliance treatment? 3. What is the frequency of laceback complications during alignment phase of orthodontic fixed appliance treatment? 4. What is the effect of laceback on pain during alignment phase of orthodontic fixed appliance treatment?

Study design:

Split-mouth randomised controlled trial. For each subject, researchers will randomly assign half of the oral cavity to receive laceback during orthodontic fixed appliance treatment, whereas the other half will not receive laceback.

Population (P) - Orthodontic patients from International Islamic University Malaysia (IIUM) aged 15 and above.

Intervention (I) - Laceback (LB) Control (C) - No laceback (no LB) Outcome (O) - Primary outcome: Plaque score (using Orthodontic Plaque Index)

Secondary outcomes:

Frequency of archwire complications Frequency of laceback complications Pain (using Visual Analogue Scale)

Study procedures:

One week after braces are put up, participants will be called back so that the researchers can put up laceback on one side of their oral cavity, and record baseline records of their oral hygiene using the Orthodontic Plaque Index (OPI). Participants are required to carry out the usual oral hygiene practices after braces and laceback are being put up. During the next 8 week observation period, they are required to notify the researcher if they suspect any breakages or loose components, so that they come to the clinic for emergency appointments. They are also required to fill up a pain diary for 4 weeks at specific time points, where pain will be recorded using a Visual Analogue Scale. After 4 weeks, participants will be recalled so that the researchers collect the pain diary, and record the plaque score, and any archwire/laceback complications. This is repeated for another 4 weeks whereby pain diary is filled up for 4 weeks at specific time points, and on the 8th week, subjects will be reclled so that the researchers collect the pain diary, and record the plaque score, and any archwire/laceback complications.

Sampling method:

Convenience sampling of orthodontic patients from the Specialist and Postgraduate Orthodontic Clinic of the Kulliyyah of Dentistry, IIUM.

Sample size calculation:

Sample size is calculated based on each specific objective. Sample size calculated for specific objective 1 was the highest and was therefore chosen.

Specific objective 1 is to assess the effect of laceback on patient's oral hygiene during alignment phase of orthodontic fixed appliance treatment. A previous split-mouth study was conducted on orthodontic patients to record their plaque score using OPI. The standard deviation (SD) of OPI was calculated to be 1.88. A difference of 1 point in OPI was deemed clinically meaningful to be detected. The sample size is calculated using G\*Power (Version 3.1.9.6). A total of 34 subjects are required for 68 sites (34 LB and 34 no LB), which would give a power of 85% with significance level of 0.05 to detect 1 unit difference in OPI score. Final sample size after considering 10% drop out rate is 38 patients (38 per group).

Randomisation:

Two-stage randomisation strategy will be employed - simple randomisation, followed by minimisation (covariate adaptive randomisation). For the first 10 subjects, simple randomisation is applied. For the subsequent 28 subjects, allocation will be determined using minimisation method. This is to balance the prespecified covariates between laceback and no laceback groups - type of premolar extracted and side of allocating laceback.

Allocation concealment is achieved by sequentially numbered, opaque, sealed envelopes containing allocation card written "left" or "right" side for laceback. As new subjects are recruited, an independent dental nurse opens the next envelope in the sequence to reveal the allocation. The prinicipal investigator is responsible for recruiting and implementing the intervention.

Blinding:

Due to the nature of the study, the participants and operator are not blinded. Some of the data collection can be blinded, i.e. recording of plaque score. During recall visits, laceback and archwires will be removed, then plaque disclosing agent will be applied. Then, plaque score will be recorded by a clinician not involved in treating the patient. All data collected will be coded and anonymised to ensure that the data analyst is blinded. The code will be held by the co-investigator and will only be revealed to the principal investigator after data analysis is completed.

Proposed statistical analysis:

Data will be analysed using IBM SPSS Statistics for Macintosh (Version 27). Normality of data will be assessed using shape of the distribution curve and Shapiro-Wilk test. Reliability assessments will be measured using Intraclass Correlation Coefficient with threshold set at 0.8 to indicate good inter- and intra-rater reliability. An intention-to-treat analysis will be employed. Missing pain scores will be imputed by last observation carried forward method.

Baseline demographic characteristics will be analysed using descriptive statistics.

For specific objective 1, to compare differences in mean plaque score between LB and no LB group over time (T0, T1, and T2), a two-way repeated measures ANOVA test will be applied if data is normally distributed. When a significant main effect or interaction is detected, post-hoc pairwise comparisons will be performed using simple effects analysis with Bonferroni correction. If normality assumption is violated, Friedman test will be applied instead.

For specific objective 2, the mean frequency of archwire complications will be recorded by summing up the number of complications that happen throughout the study period from T0 to T2. To compare differences in mean frequency of archwire complications between LB and no LB group, a paired t-test will be used if data is normally distributed. If normality assumption is violated, Wilcoxon signed-rank test will be applied instead.

For specific objective 3, mean frequency of laceback complications per subject will be reported. The number and percentage of subjects with at least two laceback complications will also be reported.

For specific objective 4, to compare differences in mean pain score between LB and no LB group over time (T0, T0 - T1, and T1 - T2), a two-way repeated measures ANOVA test will be applied if data is normally distributed. When a significant main effect or interaction is detected, post-hoc pairwise comparisons will be performed using simple effects analysis with Bonferroni correction. If normality assumption is violated, Friedman test will be applied instead.

• Frequency of archwire complications [Срок оценки: T1 - 4 weeks after T0 T2 - 4 weeks after T1 And whenever patient comes for emergency appointment between T0 and T1, and T1 to T2]
• Frequency of laceback complications [Срок оценки: T1 - 4 weeks after T0 T2 - 4 weeks after T1 And whenever patient comes for emergency appointment between T0 and T1, and T1 an T2]
• Pain during orthodontic treatment [Срок оценки: During appointment, T0 (baseline) - before laceback placement. Inside pain diary, between T0 to T1 and T1 to T2 at specific time points - 4 hours, 24 hours, 3 days, 1 week, 2 weeks, 3 weeks, 4 weeks after laceback placement.]