Table 2.
Characteristics of the included studies (TPA transpalatal arch, RCT randomized controlled clinical trial, CCT controlled clinical trial)
| Reference | Number of patients | Type of study (RCT/CCT/other) | Control intervention | Type of implant (length, material) | Number of implants | Location of implant | Mode of anchorage (direct/indirect) |
|---|---|---|---|---|---|---|---|
| Al-Sibaie and Hajeer [1] | 56 (28 implant, 28 non implant) | RCT | TPA | Self-drilling titanium mini implants (1.6 mm diameter and 7 mm length; Tuttlingen, Germany) | 2 | Between the maxillary second premolar and first molar | Direct |
| Basha et al. [4] | 14 (7 implant, 7 non implant) | RCT | TPA | Surgical steel mini implants (1.3 mm diameter, 8 mm length; SK Surgical, Pune, India.) | 2 | Placed between the roots of second premolar and first molar in the maxilla | Direct |
| Benson et al. [5] | 51 (23 implant; 24 non implant) | RCT | Headgear | Ortho implant, (6 mm length, Straumann, Waldenburg, Switzerland) | 1 | Midpalatal | Indirect |
| Chopra et al. [9] | 50 (25 implant; 25 non implant) | RCT | Nance button; lingual arch | Self-drilling titanium ortho implants | 4 | Buccal alveolar bone between the second premolars and first molars in all the four quadrants | Indirect |
| Davoody et al. [11] | 46 (23 implant, 23 non-implant group) | RCT | Intrusion arch and mushroom loops | 1.8–2 mm in width, 8–9 mm in length | 4 | Placed between maxillary second premolars and first molars in all four quadrants | Direct |
| Liu et al. [28] | 34 | RCT | TPA | Self-tapping titanium mini-screw implants (8 mm length, 1.2 mm diameter, Cibei, Ningbo, China) | 2 | Between the roots of the first molar and the second premolar | Direct |
| Upadhyay et al. [49] | 30 (15 implant, 15 non-implant) | RCT | Treatment in control group not specified: Nance holding arch, extraoral traction, banding of the second molars, and differential moments | Custom made at our institute by modifying conventional surgical screws, measuring 1.3 mm in diameter and 8 mm in length | 2 | Placed between the maxillary second premolar and first molar, preferably between the attached and movable mucosae | Direct |
| Upadhyay et al. [48] | 23 | Other (cohort study) | No control group | Titanium mini implants (1.3 mm in diameter and 8 mm in length) | 2 | Placed between the roots of the first molar and the second premolar in both upper quadrants | Direct |
| Upadhyay et al. [50] | 40 (20 implant, 20 non implant) | RCT | Conventional methods such as headgears, transpalatal arches, banding of second molars, application of differential moments | Titanium mini implants (1.3 mm diameter, 8 mm length) | 4 | Between the roots of the first molar and second premolar in all four quadrants | Direct |
| Victor et al. [52] | 20 (10 implant, 10 non-implant) | RCT | NiTi closed coil spring | Absoanchor—SH 1312-08; (1.3 mm diameter, 8 mm length) | 4 | Placed between the roots of second premolar and first molar in the upper arch, the screw insertion was angulated at 40° and 8 mm gingival to the archwire | Direct |
| Wehrbein et al. [54] | 9 | Other (cohort study) | No control group | Orthosystem (diameter 3.3 mm, lengths are 4 and 6 mm) | 1 | Midpalatal | Indirect |
| Wilmes et al. [57] | 20 (10 in implant group of which 5 patients had additional transversal reinforcement and 5 did not, 10 in non-implant group) | CCT | TPA | 2.0 × 10 mm, Dual Top™, Jeil Medical Corporation, Seoul, South Korea, or 2.0 × 11 mm, BENEFIT, Mondeal Medical Systems, Mühlheim a.d. Donau, Germany | 1 | Placed in the anterior palate | Indirect |