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Occlusal and near occlusal contacts measured at T0, T2 and T3 for each retainer type_ Recorded as median and IQR due to data not being of normal distribution_
| T0 Median (IQR) | T2 Median (IQR) | T3 Median (IQR) | |||||
|---|---|---|---|---|---|---|---|
| Sensitivity measurement (mm) | Anterior | Posterior | Anterior | Posterior | Anterior | Posterior | |
| Vivera® | < 0.2 | 1 (0–3) | 7 (3–7) | 2 (1–5) | 1.5 (0.75–4.25) | 6 (3.5–7) | 8 (7–11) |
| 0.2 < x < 0.4 | 7 (2–7.25) | 7.5 (6.75–8) | 5 (1.75–7) | 8 (4–8) | 7 (4.5–9) | 14 (11–5.5) | |
| Duran® | < 0.2 | 1 (0–3) | 7 (3–7) | 2 (1–5) | 7 (3–11) | 4 (2–5) | 12 (11–13) |
| 0.2 < x < 0.4 | 3 (1–6) | 11 (7–15) | 4 (2–6) | 14 (12–17) | 6 (2–6) | 18 (15–22) | |
Patient demographic information at the time of T0 and pre-treatment clinical characteristics of subjects in Vivera® and Duran® retainer groups_
| Vivera® | Duran® | |
|---|---|---|
| Gender | ||
| Male | 4 (40%) | 6 (42.8%) |
| Female | 6 (60%) | 8 (57.1%) |
| Age (yr) | ||
| Median (IQR) | 34 (28–48) | 31 (26–38) |
| Pre-treatment characteristics | ||
| Skeletal classification | ||
| Class I | 5 (50%) | 8 (57.1%) |
| Class II | 4 (40%) | 6 (42.8%) |
| Class III | 1 (10%) | 0 |
| Dental classification | ||
| Class I | 7 (70%) | 10 (71.4%) |
| Class II division 1 | 2 (20%) | 1 (7.1%) |
| Class II division 2 | 1 (10%) | 3 (21.4%) |
| Class III | 0 | 0 |
| Missing teeth (excluding third molars) | ||
| None | 9 (90%) | 14 (100%) |
| Missing two premolars | 1 (10%) | 0 |
| Missing four premolars | 0 | 0 |
The secondary outcomes (stability and occlusal settling) measurement methods are displayed_
| Unit | Description | |
|---|---|---|
| Stability | ||
| Little's Irregularity Index | mm | The sum of the five contact point displacements for the anterior teeth. |
| Occlusal settling | ||
| Occlusal contacts | Number of contacts | The numerical value of contact points measured on the mandibular arch. |
Occlusal and near occlusal contact results analysed using non-parametric Mann–Whitney test and presented as median, IQR and P-value_
| Sensitivity measurement | Location | Vivera® Median (IQR) | Duran® Median (IQR) | P-value |
|---|---|---|---|---|
| Number of occlusal contacts at T0 | ||||
| Occlusal contact | Anterior | 1 (0–3) | 1 (0–3) | 0.46 |
| Posterior | 7 (3–7) | 7 (3–7) | 0.01* | |
| Near occlusal contact | Anterior | 7 (2–7.25) | 3 (1–6) | 0.37 |
| Posterior | 7.5 (6.75–8) | 11 (7–15) | 0.08 | |
| Change in number of occlusal contacts from T0 to T2 | ||||
| Occlusal contact | Anterior | 0.5 (−0.5 to 1.25) | 1 (0–2) | 0.65 |
| Posterior | 0.5 (−1.25 to 1.25) | 1 (−1 to 2) | 0.81 | |
| Near occlusal contact | Anterior | 0 (−1.25 to 0) | 0 (−1 to 1) | 0.41 |
| Posterior | 0.5 (−3.25 to 1.25) | 0 (−1 to 4) | 0.6 | |
| Change in number of occlusal contacts from T2 to T3 | ||||
| Occlusal contact | Anterior | 2 (0.5–3) | 0 (0–1) | 0.3 |
| Posterior | 7 (4–10) | 5 (4–9) | 0.54 | |
| Near occlusal contact | Anterior | 1 (−0.5 to 4) | 0 (0–3) | 0.06 |
| Posterior | 10 (3–11.5) | 1 (0–6) | 0.3 | |
Reason for retainer failure over 6 months, including initial and subsequent retainers inserted_
| Vivera® Retainer | Duran® Retainer | |||
|---|---|---|---|---|
| Total number of subjects | 9 | 14 | ||
| Total number of retainers | 18 | 41 | ||
Stability measurements of Little's Irregularity Index (mm)_ Data are presented in the form of mean, standard deviation and P-value due to normal distribution_
| Vivera® | Duran® | 95% CI | ||||||
|---|---|---|---|---|---|---|---|---|
| Little's Irregularity Index | Mean | SD | Mean | SD | P-value | Difference in Mean | Lower | Upper |
| Pre-treatment maxillary | 5.62 | 2.77 | 7.55 | 2.83 | 0.16 | 1.93 | −4.67 | 0.83 |
| Pre-treatment mandibular | 7.53 | 4.1 | 8.03 | 3.9 | 0.8 | 0.5 | −4.48 | 3.48 |
| 3-month relapse (T2–T0) maxillary | 0.35 | 0.5 | 0.51 | 0.39 | 0.47 | 0.16 | −0.62 | 0.3 |
| 3-month relapse (T2–T0) mandibular | 0.34 | 0.31 | 0.24 | 0.4 | 0.55 | 0.1 | −0.24 | 0.44 |
| 6-month relapse (T3–T2) maxillary | 0.13 | 0.08 | 0.33 | 0.32 | 0.14 | 0.2 | −0.46 | 0.08 |
| 6-month relapse (T3–T2) mandibular | 0.51 | 0.53 | 0.29 | 0.55 | 0.43 | 0.22 | −0.38 | 0.83 |
Comparison of the number of occlusal and near occlusal contacts following full-time and night-time wear regimes for each retainer type_ Assessed using non-parametric, paired Wilcoxon Signed Rank test_ P-value recorded_
| T0 vs T2 | T2 vs T3 | ||||
|---|---|---|---|---|---|
| Sensitivity Measurement (mm) | Anterior | Posterior | Anterior | Posterior | |
| Vivera® (P-value) | < 0.2 | 0.92 | 0.86 | 0.06 | 0.02* |
| 0.2 < x < 0.4 | 0.11 | 0.73 | 0.21 | 0.05* | |
| Duran® (P-value) | < 0.2 | 0.11 | 0.43 | 0.75 | 0.03* |
| 0.2 < x < 0.4 | 0.96 | 0.37 | 0.46 | 0.11 | |