Skip to main content

Table 2 Summary of the data from the included studies

From: Effects of micro-osteoperforations performed with Propel system on tooth movement, pain/quality of life, anchorage loss, and root resorption: a systematic review and meta-analysis

Author, year, and study design Sample size (n), M/F (n), and mean age ± SD Malocclusion Bracket system, Archwire Anchorage
Force system
MOP protocol Follow-up/loss Rate of tooth movement (mm/month) Outcomes evaluated Outcome measurements Conclusions
Maxilla Mean ± SD
Mean ± SD
Mean ± SD
Mandible Mean ± SD
Sivarajan et al., Malaysia, 2018
Split-mouth [26]
30, 7/23, 22.2 ± 4.00 Class I, < unit class II, or class III MBT 0.022 × 0.028″ 0.018 × 0.025″ SS mini-screws; elastomeric chain 140–200 g Orlus screw (width 1.6 and length 6). Three separate MOPs, vertical direction 2 mm apart and 3 mm in depth. One-time application at the start of retraction 4 m/0 1.02 ± 0.55
Clinical measurements using electric digital calipers. Self-administered questionnaire (5-point Likert scale and VAS) Distance from the central point of the canine bracket to superior margin of the mini-implant (maxilla) and the inferior margin of the mini-implant (mandible); overall pain intensity and impact of any pain on daily function MOPs were associated with significant increased overall canine retraction over a 16-week period of observation, however not clinically significant; moderate pain was associated with MOP at 4-week intervals; mild pain in 8 and 12 weeks.
Alikhani et al., New York 2013.
Split-mouth [12]
20, 8/12, 25.8 Class II div 1 MBT 0.022 × 0.028″
0.016 × 22″ SS
100 g NiTi closing coil springs
Propel. Three MOPs distal to the canines, each perforation was 1.5 mm wide and 2 to 3 mm deep. One-time application at the start of retraction 1 m/0 0.45 ± 0.55
Cast measurements with digital caliper. Gingival crevicular (GCF) fluids analysis. Rating scale from 1 to 10 for the level of discomfort The distance between the canine and the lateral incisor in 3 points: incisal, middle, and cervical of the crowns. GCF collected before and after each visit to access the level of inflammatory response. Pain and discomfort levels at 24 h, 7, 14, and 28 days after the beginning of canine retraction MOPs increased the rate of canine retraction 2–3-fold compared with the control group, reducing treatment time by 62%. Patients reported only mild discomfort locally at the spot of the MOP. At days 14 and 28, little to no pain was experienced.
Attri et al., India, 2018
Parallel control group [25]
60, 27/33, 17.8 ± 2 NA MBT 0.022 × 0.028″
0.019 × 0.025″ SS.
Trans-palatal arch
tie-backs (150 g)
Propel. Three MOPs in the extraction space, 1.5 mm wide and 2–3 mm deep. Repeated after every 28 days until space closure was completed Until space closure/0 0.58 ± 0.15
0.51 ± 0.10
Digital images using a 3D scanning of the plaster models. A 10-mm VAS The extraction space, a mid-palatine line drawn from distal surface of canine to the mesial surface of the 2nd premolar. Pain perception at 24 h, 7 days, and 28 days after MOP Acceleration of tooth movement was seen with MOPs. Minimal discomfort was observed post-procedure for participants who had undergone MOPs.
Kundi et al., Saudi Arabian, 2019
Parallel control-group [13]
30, 14/16, 27.9 ± 4.5 Class II div 1 MBT 0.022 × 0.028″
Rectangular wires
Banding 1st and 2nd Molars
Niti coil springs 100 g
Propel. Three separate MOPs’ distal in the canine, 1.5 mm diameter and 2.5 mm in depth. One-time application at the start of retraction 4 m/0 0.58 ± 0.12
Digital images using a 3D scanner of the plaster models. Numerical rating scale (NRS) The distance between the tip of the canine and the midpoint of incisor edge of lateral incisor, and the cervical midpoints on height of contours of respective cingulum x and y coordinates on 3D images. Pain intensity at 4 h after the procedure, and after every 24 h for the next 7 days MOPs accelerated orthodontic tooth movement by 2–3-fold. A significant difference was found in the perception of pain among experimental and control group on the 1st and 2nd days. However, the difference was insignificant during the rest of the week.
Fattori, Brazil, 2020
Parallel control group [19]
18, 7/11, 24.1 ± 6 Severe class III SLB Roth 0.022″
019 × 25″ SS
9 mm Niti closed coil spring (200 g)
Propel. Three vertical MOPs in the midway space between canine and 2nd premolar, 6–8 mm deep. Repeated after every activation session until space closure was completed 9 m/control:3
0.61 ± 0.17
Digital measurements using Q3DC tool (plaster dental models digitally converted). Treatment time. OHIP-14 questionnaire Distance from the most distal point in the canine and most mesial point in the 2nd premolar. Closing time between groups (mm/month). Quality of life assessment Three MOPs were inefficient for accelerating tooth movement during anterior retraction. MOPs produced more impact on OHRQOL immediately following the MOP procedure and after 3 days.
Aboalnaga et al., Egypt, 2019
Split-mouth [15]
18, all females, 20.5 ± 3.9 NA Roth 0.022″
0.017 × 0.025 SS wire mini-screws
Niti closing coil springs (150 g)
Mini-screw (UNITEK), 1.8 × 8 mm. Three MOPs were performed midway in the extraction space, using a TAD 1.8 × 8mm.
One-time application before canine retraction
4 m/0 0.44 ± 0.23
Dental models (T0–T4) scanned (images superimpositions). CBCT images before and after treatment. Pain Rating Scale (1–10) The distance between the canine cuspid tip and frontal plane (FP) in each model (T0–T4). Rate of canine retraction, and the sagittal distance between the mesiobuccal cusp tip of the 1st molar and FP was used to measure anchorage loss. Pain intensity assessed immediately after MOPs, 1 day, 3 days, and 1 week after intervention. Root resorption MOPs were not able to accelerate the rate of canine; however it seemed to facilitate root movement. Mild to moderate transient pain was experienced following the MOP procedures that almost disappeared 1 week later. No anchorage loss or root resorption was detected.
Haliloglu-Ozkan et al., Turkey, 2018
Parallel control group [18]
32, 19/13, 15.7 ± 1.5 NA MBT .022 × .028 0.019″ × 0.025″ brass-posted wire mini-screws
NiTi closing coil spring 150 g
Mini-screw (MTN-2), 1.6 × 8 mm. Three MOPs were performed in the distal of the canine, depth: 5 mm. Repeated in the 4th week of distalization 2 m/control:3
1.36 ± 0.81
1.01 ± 0.71
Plaster models scanned Canine distalization, canine rotation, and canine tipping and molar mesialization. Anchorage loss MOPs significantly increased the canine distalization rate at the T1–T3 interval in the maxilla (0.4 mm). The new MOPs performed at T3 did not trigger the canine distalization rate. Tooth movement was faster in the maxilla than in the mandible.
Feizbakhsh et al., Iran, 2018
Split-mouth [27]
20, 12/8, 28 Class I Roth 0.022 × 0.028 0.019 × 0.025 SS wire
2nd molar.
Niti coil 200 g
Mini-screw (Jeil Medical), 1.6 × 3 mm. Two MOPs were performed in 5 mm and 8 mm of crestal bone. Bony screw 1.6 mm diameter and 3 mm length. One-time application at the start of retraction 1 m/0 0.74 ± 0.40
0.53 ± 0.41
Plaster models scanned Distance between the canine and the 2nd premolar measured in three areas: center of the canine and premolar bracket, the canine cusp tip and premolar buccal cusp tip, and the shortest distance between canine and premolar cervico-gingival line MOPs increased the rate of tooth movement by more than 2-fold when compared to the control side. No significant difference in the rate of tooth movement in the canine retraction, maxilla, and mandible, between interventional and control.
Alkebsi et al., Jordan, 2018
Split-mouth [14]
32, 8/24, 19.3 ± 2.5 Class II div 1 MBT 0.022 × .028 0.019 × 0.025 SS wire
NiTi closed coil spring 150 g.
Mini-screw (Aarhus), 1.5 × 6 mm. Three MOPs of 1.5 mm width and 3 to 4 mm, 3 mm distal to canine and 6 mm from the free gingival margin. One-time application before retraction 3 m
0.67 ± 0.34
3D models obtained every month; clinical measurements using a digital caliper; digital periapical radiographs; VAS; periodontal clinically evaluation Amount of canine displacement, rate of canine retraction, anchorage loss, canine tipping, canine rotation, root resorption, plaque index, gingival index, pain level, patients’ satisfaction and degree of ease, willingness to repeat the procedure and recommendation to others Three MOPs were not effective for accelerating tooth movement. No significant differences of anchorage loss, canine rotation, and tipping. Root resorption was similar for both groups. No adverse effect of periodontal health. The level of pain was minimal and faded after 24 h on both sides. MOPs had no effect on the patients’ daily life except for a feeling of swelling on the first day. Patients’ level of satisfaction regarding the MOP was high.
Puetter, Brazil, 2018
Split-mouth [20]
17, 8/9, 16.5 ± 4.4 NA Edgewise 0.022 × 0.028
0.018 × 0.025 wire,
CrNi coil spring 150 g or elastomeric 150 g
Propel. Three MOPs switch a depth of 5 mm distal and parallel to the canine root. One-time application at the start of retraction 2 m/NA 1.26 ± 0.40
Digital models obtained using a 3D scanner. Panoramic radiographs with radiopaque markers Anteroposterior distances between canine cusp tips and PMs. Angle formed between the long vertical and mesiodistal axis of the canines. Discomfort questionnaire with four questions, three answered by VAS scale. MOPs do not accelerate tooth movement significantly. The perception of MOP discomfort was considered mild to moderate.
Alqadasi et al., China, 2019
Split-mouth [28]
8, NA, 15 to 40 Class II div 1 MBT
Niti Coil spring 150 g
Automated mini-implant instrumentation. Three perforations of 1.5–2 mm width and 5–7 mm depth in the middle of the extraction space. One-time application at the start of retraction 3 m/NA 0.56 ± 0.41
Digital images from 3D scanner; photographs and CBCT images; McGill Pain questionnaire The distance between canine and second premolar; a point on the crown tip and the apex tip; the distance between cementoenamel junction and marginal bone crest from the buccal and lingual sides; numeric scale for pain intensity MOPs do not significantly speed up tooth movement. Pain and discomfort appear to be exactly similar on both sides. No difference between groups regarding bone height and root resorption.
Babanouri et al., Iran, 2020
Split-mouth [29]
28, 7/5, 26.1 ± 9.1 Class II div 1 MBT 0.022-in
0.016 × 0.022″ SS wire mini-screw
NiTi closed coil spring 150 g
Mini-screws 1.2 mm diameter. Three perforations with to a depth of 1 mm, between the distal of the canine and the mesial of the 2nd premolar. The first MOP was located 5 mm away from the free gingival margin. One-time application at the start of retraction 3 m
Control: 2
MOP: 2
0.62 ± 0.11 0.76
Plaster models measured using a digital caliper; VAS The distance between the canine and lateral incisor measured at three points (incisal, middle, and cervical). The amount of pain associated to MOP was evaluated in the day of canine retraction and 24 h later. MOPs were effective in accelerating tooth movement over a period of 3 months, but not clinically significant. There was no increase in the level of pain and discomfort due to MOPs.
  1. NA not available, MOPs micro-osteoperforations, MBT McLaughlin-Bennet-Trevisi, SS stainless steel, NiTi niquel-titanium, OHIP oral health impact profile, SD standard deviation, GCF gingival crevicular fluid, TAD temporary anchorage device, CBCT cone beam computed tomography, VAS visual analogue scale