■ The mean difference of anchorage loss between miniscrews and conventional anchorage was −2.4 mm (95% CI: −2.9 to −1.8 mm),21 −1.68 mm (95% CI: −2.27 to −1.09 mm),22 −1.87 mm (95% CI: −2.21 to −1.53 mm),23 −2.01 mm (95% CI: −2.45 to −1.58 mm),26 −1.94 mm (95% CI: −3.46 to −0.42 mm)30

■ Miniscrews were more effective for anchorage reinforcement than conventional anchorage methods in the mandible (mean difference −3.1 mm) than in the maxilla (mean difference −2.2 mm) and in adults than in young patients.21

■ There was greater but non-statistically significant distal molar tipping with miniscrews when compared to conventional anchorage methods.23 On the other hand, another meta-analysis32 reported (from one study) that mesial tipping of maxillary and mandibular molars was significantly greater with the conventional anchorage methods than with miniscrews by 2.15˚ and 2.5˚, respectively.

■ Anchorage loss was significantly lower in the miniscrew group when compared to TPA alone (mean difference −2.09 mm, 95% CI: −2.38 to −1.8 mm), TPA and headgear (mean difference −1.71 mm, 95% CI: −2.6 to −0.81 mm), and TPA and utility arch (mean difference −0.63 mm, 95% CI: −1.15 to −0.12 mm).24

■ Miniscrews are either associated with no anchorage loss or with “anchorage gain” in contrast to the conventional anchorage methods (mainly TPA) and the significant mean difference was −2.79 mm (95% CI: −3.56 to −2.03 mm).27

■ Miniscrews achieved maximum anchorage with significantly less mesial movement of first molar of −1.48 mm (95% CI: −2.25 to −0.72 mm) than conventional anchorage. This difference between the two methods was greater for patients aged less than 18 years (−2.36 mm, 95% CI: −4.18 to −0.53 mm) than those older than 18 years (−1.2 mm, 95% CI: −2.01 to −0.39 mm).31

■ Anchorage loss was greater with conventional anchorage compared to mid-palatal implants (mean difference −1.02 mm, 95% CI: −2.31 to 0.26 mm) and alveolar miniscrews (mean difference −2.17 mm, 95% CI: −2.58 to −1.77 mm).22

■ Anchorage loss with miniscrews was significantly lower in the following situations: when the miniscrews were placed in the mandible than in the maxilla (−0.6 mm vs. 0.2 mm), when the miniscrews were placed between the second premolar and first molar than palatally (−0.2 mm vs. 1.3 mm), when two miniscrews were placed rather than one (−0.2 mm vs. 1.3 mm), when miniscrews were loaded directly rather than indirectly (−0.2 mm vs. 0.8 mm), and when there was absence of pre-treatment space loss rather than existing loss (−0.4 mm vs. 0.9 mm).21

■ Anchorage loss was in favor of dual miniscrews than single miniscrews (mean difference −1.62 mm, 95% CI: −2.26 to −0.98 mm).22

■ Indirect anchorage with miniscrews was associated with greater anchorage loss than that of direct anchorage with miniscrews but still lower than that of the conventional anchorage methods.27

■ En-masse retraction with miniscrews and “two-step retraction” with conventional anchorage methods: the maxillary first molar was moved distally with miniscrews and moved mesially with conventional anchorage with a significant mean difference of −3.03 mm (95% CI: −3.65 to −2.42 mm).28

■ En-masse retraction with miniscrews and conventional anchorage: There was significantly greater anchorage loss with conventional anchorage (mean difference −1.17 mm, 95% CI: −1.81 to −0.53 mm).29

■ Two-step retraction technique: anchorage preservation was greater with miniscrews than with the conventional anchorage methods both in the maxilla (mean difference −1.56 mm, 95% CI: −1.98 to −1.14 mm) and the mandible (mean difference −1.62 mm, 95% CI: −2.01 to −1.24 mm) with an overall greater effect of the direct anchorage method.32

■ Miniscrews were associated with less vertical anchorage loss (extrusion) compared to the conventional anchorage (mean difference −1.76 mm, 95% CI: −2.56 to −0.97 mm27; −0.61 mm, 95% CI: −1.08 to −0.15 mm28; and −1.26 mm, 95% CI: −1.86 to −0.67 mm29) and in the majority of the studies, molar intrusion was associated with miniscrews. These differences were statistically significant. Similar results were also found but this was not statistically significantly different.31

■ There was statistically significantly greater incisor retraction in favour of miniscrews when compared to conventional anchorage methods. The difference was 1.37 mm (95% CI: 0.83 to 1.91 mm),23 1.5 mm (95% CI: 1.17 to 1.84 mm),26 0.46 mm (95% CI: 0.04 to 0.87 mm) with better incisor inclinations (mean difference 0.74˚, 95% CI: 0.25˚ to 1.23˚),28 and 0.47 mm (95% CI: 0.07 to 0.87 mm) (however, this significance was only for patients older than 18 years).31

■ Incisor tipping was slightly greater but the difference was not statistically significant with miniscrews,23 while the reverse was found with another review26 but again with no significant difference.

■ When both anchorage methods were used with en-masse retraction, no significant differences in incisor retraction and incisor inclination were reported.29

■ There was significantly greater canine retraction in the two-step retraction technique with the use of miniscrews than with conventional anchorage methods both in the maxilla (mean difference 0.43 mm, 95% CI: 0.16 to 0.69) and the mandible (mean difference 0.26 mm, 95% CI: 0.02 to 0.49). Distal tipping of the canines was also greater in the miniscrew group than in the conventional anchorage group in both arches by about 3˚, however this difference was not statistically significant.32

■ Incisors were intruded with miniscrews and extruded with conventional anchorage methods with a significant mean difference of 2.48 mm (95% CI: 1.77 to 3.19 mm)28 and 1.87 mm (95% CI: 0.09 to 3.65 mm).29 Similar results were found with another review but with no significant difference.31

■ Miniscrews as compared to conventional anchorage methods did not show a significant difference in SNA angle, but there was a significant reduction in SN-MP angle with miniscrews by 1.12˚ (95% CI: 0.03˚ to 2.21˚).26

■ En-masse retraction with miniscrews and two-step retraction with conventional anchorage: no significant differences in terms of SNA, SNB, ANB, and SN-MP angles.28

■ En-masse retraction with miniscrews and conventional anchorage methods: no significant differences of SNA, SNB, and ANB, while, SN-MP was significantly increased with conventional anchorage (mean difference 1.12˚).

■ The nasolabial angle increased with miniscrews significantly by 3.52˚ (95% CI: 1.17˚ to 5.87˚)26 and 4.73˚ (95% CI: 1.30˚ to 8.17˚).28

■ Two reviews found a significant reduction of upper lip with miniscrews.26^,29 The reduction of upper lip to E-line (0.73 mm, 95% CI: 0.28 to 1.17 mm) with miniscrews rather than conventional anchorage methods.26 Another review28 found that there was a greater but not statistically significant reduction of upper lip to E-line in the miniscrew group.

■ There was a significantly greater lower lip to E-line reduction with miniscrews compared to conventional anchorage methods (0.95 mm, 95% CI: 0.21 to 1.69 mm).28 While, no significant difference in lower lip was reported in a different review.29

■ There was a tendency to a decrease in the facial convexity angle with skeletal anchorage methods than with conventional anchorage methods.26^,28^,29

■ The duration of space closure was not significantly shorter with surgical anchorage than with conventional anchorage methods (the difference was only 12 days).22

■ No significant difference in the duration of space closure between miniscrews and TPA groups.30

■ Although the duration of space closure was not significantly different between single and dual miniscrews, the difference was 2.19 months (95% CI: –1.97 to 6.35 months) in favour of single miniscrews.22

■ A non-significant reduction in the overall duration of treatment was found with surgical anchorage (miniscrews and mid-palatal implants) by 0.15 years (95% CI: –0.07 to 0.37 years) than that with conventional anchorage methods.22 Using miniscrews also did not show a significant difference in the duration of treatment in comparison to TPA, Nance appliances, or headgear. Overall duration of treatment was shorter by 1.1 months (95% CI: –1.79 to 3.98 months) in favor of those treated using miniscrews for anchorage.30

■ A similar finding was identified of no significant shorter duration of treatment with miniscrews than conventional anchorage when both were used with en-masse retraction (mean difference 1.15 months).28^,29

■ One meta-analysis found significant shorter treatment duration when using miniscrews by 4 months (95% CI: 2.21 to 5.79 months) than when using conventional anchorage.23

■ A Cochrane review found (from one study) that the mean number of appointments to complete the treatment was shorter by seven appointments for conventional anchorage.22

■ A meta-analysis found (from one study) that number of appointments was shorter in the miniscrews group compared to headgear and Nance appliance groups by one and three appointments, respectively.30

■ Using Peer Assessment Rating index (PAR index), the quality of treatment was better when using miniscrews as compared to headgear (statistically significant) and Nance appliance (not significantly different). But again, this was from one study and no meta-analysis was conducted.30

■ Pain was reported to last slightly longer with the conventional anchorage than with the surgical anchorage. While, discomfort was highest on the evening after onplant surgery. Placement and removal of implants was also associated with pain perception. Pain perception was reported to be lower with pre-drilling than with self-drilling miniscrews.22

■ Although a mild level of discomfort was reported during the insertion and removal of miniscrews and Nance appliances, the positive feedback, comfort, and compliance were greater with miniscrews than that with headgear and Nance appliance.30

■ Although no pooled data is available, a higher failure rate was found with conventional anchorage than with surgically-placed anchorage.22

■ Albeit few and with minimal complications, the failure rate was greater with miniscrews than with conventional anchorage methods.30

■ It was reported that the failure rate of miniscrews was about 10% which sometimes can be replaced immediately or it may lead to peri-implant inflammation that may need discontinuation of treatment until improvement of oral hygiene.27

■ The failure rate of miniscrews was reported to be about 12%.21

■ Early and delayed loading of surgical anchorage have similar success rates.22