Table 3.
Meta-analysis data for the stability of Herbst appliance Tx derived from 19 studies. The weighted data (weighted according to the number of patients of each individual study) for ANB angle, Wits appraisal, sagittal molar relationship [data from studies using millimetres and cusp widths (cw) shown separately], soft-tissue profile convexity excluding nose, overjet, and overbite are shown. The references, total number of patients, weighted mean pre-Tx age, Tx changes, duration of post-Tx observation period (months), post-Tx changes as well as final values are shown.
| Variable | References | Number of patients | Pre-Tx age (weighted) | Tx changes* (weighted) | Duration of post-Tx observation period in months (weighted) | Post-Tx relapse* (weighted) | Final value (weighted) | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| n | mean (years) | mean | mean | min | max | mean | min | max | mean | ||
| ANB angle (n = 12) | (44,47,48,49,51,54,55,56, 57,60,61,63) | 254 | 15.0 | −1.5° | 34.0 | 12 | 78 | 0.2° | −0.8° | 0.8° | 4.1° |
| Wits appraisal (n = 6) | (47,48,51,60,61,62) | 143 | 16.0 | −2.6 mm | 24.2 | 12 | 36 | 0.5 mm | 0.1 mm | 1.8 mm | 0.1 mm |
| Sagittal molar relationship (n = 12) | (44,45,46,47,48,50,51,57, 59,60,61,63) | 310 | 15.7 | −5.1mm, −0.8 cw | 49.7 | 12 | 382 | 1.2mm, 0.1 cw | 0.1mm, 0.0 cw | 2.4mm, 0.2 cw | −2.0 mm**, 0.1 cw*** |
| Soft-tissue profile convexity (n = 4) | |||||||||||
| Class II:1 | (44,47,58,63) | 120 | 14.4 | −3.2° | 56.5 | 12 | 74 | 0.0° | −0.8° | 0.6° | 160.6° |
| Overjet (n = 11) | |||||||||||
| Class II:1 | (44,45,47,50,53,55,57,59,60,61,63) | 266 | 14.4 | −6.5 mm | 63.1 | 12 | 382 | 1.8 mm | 0.0 mm | 3.4 mm | 3.8 mm |
| Overbite (n = 8) | |||||||||||
| Class II:1 | (47,50,53,55,57,59,61,63) | 178 | 14.9 | −2.9 mm | 81.4 | 12 | 382 | 1.4 mm | −0.7 mm | 2.3 mm | 3.7 mm |
| Overbite (n = 4) | |||||||||||
| Class II:2 | (46,48,49,62) | 109 | 16.0 | −4.4 mm | 26.3 | 12 | 34 | 1.0 mm | 0.9 mm | 1.2 mm | 2.8 mm |
*Negative Tx and post-Tx changes mean favourable development regarding Class II correction (=no relapse).
**0.0mm means edge-to-edge Class II relationship (=0.5 cw).
***0.0 cw means Class I relationship.