Introduction
Materials and methods
Ethics
Registration and reporting
Search strategy
Types of studies
PICOs
Population
Intervention and comparators
Outcome
Selection of studies
Data extraction and management
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Author/title/year of study
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Design/setting of the study
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Number/age
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Intervention and comparator/treatment duration
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Type of clinical outcome
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Method of outcome assessment
Quality assessment
Dealing with missing data
Results
Author, year | Study design | Population | Intervention | Comparison | Outcomes |
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Morales-Burruezo et al., 2020 [18] | Retrospective study | 114 participants; aged 18–75 years | -Efficacy for arch expansion (transverse distance variation) at the level of upper maxillary canine, first and second premolars, and first and second molars -Efficacy for upper maxillary first molars rotation and inclination -Predictability of ClinCheck® software movements’ previsions | ClinCheck® software (planned vs achieved) | Transverse expansion -Canines (1.87 SD 1.78 mm, + 6.31%) -First premolars (3.14 SD 2.25 mm, + 8.73%) -Second premolars (3.45 SD 2.09 mm, + 8.42%) -First molar (2.57 SD 1.83 mm, + 5.64%) -Second molar (0.45 SD 1.83 mm, + 0.54%) Inclination right first molar: 2.26 SD 4.76 mm Inclination left first molar: 2.13 SD 4.09 mm Rotation right first molar: 2.22 SD 4.37 mm Rotation left first molar: 2.46 ± 3.75 mm Predictability -Intercanine distance: 0.63 SD 0.75 (74.8%) -First premolar: 0.77 SD 1.44 mm (80.3%) -Second premolar: 0.81 SD 1.26 mm (81.0%) -First molar: 0.69 SD 1.21 mm (79.1%) -Second molar: 0.25 SD 1.97 mm (65.2%) -Inclination right first molar: − 0.42 SD 3.36 mm (123.5%) -Inclination left first molar: − 0.88 SD 2.73 mm (170.4%) -Rotation right first molar: 0.54 SD 3.05 mm (80.4%) Rotation left first molar: − 0.34 SD 3.57 mm (115.3%) |
Houle et al., 2017 [19] | Retrospective study | 64 participants Aged: 18–61 years (mean age 31.2 years) | Accuracy of transverse width measured at: - Level of canine tip and gingival margin -First premolar tip and gingival margin -Second premolar tip and gingival margin -First molar tip and gingival margin | ClinCheck® software (planned vs achieved) | Predictability of transverse expansion: Upper arch-Canine tip: 0.22 SD 0.74 mm (88.7%) -Canine gingival margin: 0.6 SD 1.02 mm (67.8%) -First premolar tip: 0.58 SD 1.14 mm (84.7%) -First premolar gingival margin: 1.09 SD 1.22 mm (67.6%) -Second premolar tip: 0.75 SD 1.54 mm (81.7%) -Second premolar gingival margin: 1.3 SD 1.61 mm (62.3%) -First molar tip: 0.77 SD 1.84 mm (76.6%) -First molar gingival margin: 1.43 SD 1.9 mm (52.9%) Lower arch -Canine tip: − 0.08 SD 0.81 mm (100%) -Canine gingival margin: 0.65 SD 1.01 mm (61%) -First premolar tip: 0.07 SD 0.96 mm (96.9%) -First premolar gingival margin: 0.27 SD 1.00 mm (88.4%) -Second premolar tip: 0.07 SD 1.15 mm (98.9%) -Second premolar gingival margin: 0.38 SD 1.16 mm (85.5%) -First molar tip: 0.03 SD 1.33 mm (100%) -First molar gingival margin: 0.54 SD 1.34 mm (70.7%) |
Krieger et al., 2012 [20] | Extended study based on previous pilot study | 50 participants; Aged 15–63 years (mean 33 SD 11.9) | Accuracy of: -Upper/lower anterior arch length -Intercanine distance -Overjet -Overbite -Dental midline shift -Irregularity index according to little | ClinCheck® software (planned vs achieved) | Little’s irregularity index: -Upper dentition: from 5.39 SD 2.23 mm before treatment to 1.57 SD 0.98 mm post-treatment -Lower dentition: from 5.96 SD 2.39 mm to 0.82 SD 0.50 mm -Difference between clinically achieved and planned reduction of Little’s irregularity index was 0.04 SD 0.65 mm for the upper anterior arch and 0.01 SD 0.48 mm for the lower anterior arch Upper inter-canine distance From 33.51 SD 2.05 mm pre-treatment to 33.67 SD 2.00 mm post-treatment -Difference between clinically achieved and planned upper intercanine distance variation was − 0.13 SD − 0.59 Lower inter-canine distance: From 24.57 SD 1.69 mm to 25.27 SD 1.52 mm Overjet From 4.31 SD 1.43 mm to 2.94 SD 0.94 mm -Overjet variation − 0.34 SD 0.54 mm Overbite From 4.05 SD 1.50 mm to 3.49 SD 1.19 mm -Overbite variation − 0.71 SD 0.87 mm Dental midline shift From 1.38 SD 0.99 mm to 0.99 SD 0.89 mm -Dental midline shift − 0.24 SD 0.46 mm |
Lanteri et al. 2018 [14] | Retrospective study | 200 participants Aged 14–56 years | -Anterior dental crowding measured with little irregularity index or Peer Assessment Rating index (PAR) | Smart track aligners vs conventional fixed appliances | Invisalign -63/100 (80.9%) fully resolved their anterior dental crowding and did not need any refinement - PAR index: 22.5 SD 7 to 3.5 SD 3 - Maxillary Little Index Pre-treatment 23% moderate/62% minimal Post-treatment 100% perfect alignment -Mandibular Little Index Pre-treatment 12% severe/36% moderate/52% minimal Post-treatment 92% perfect alignment/8% minimal Treatment duration 14 SD 7 months Conventional fixed appliance - PAR index: 24.0 SD 6 to 4.5 SD 4 - Maxillary Little Index Pre-treatment 31% moderate/69% minimal Post-treatment 100% perfect alignment -Mandibular Little Index Pre-treatment 16% severe/32% moderate/52% minimal Post-treatment 88% perfect alignment/12% minimal Treatment duration 19 SD 4 months |
Simon et al., 2014 [11] | Case–control (split mouth) | 30 participants Aged 13–72 years | Accuracy: -Upper incisor torque > 10° -Premolar derotation > 10° -Upper molar distalization > 1.5 mm | Invisalign® with and without auxiliaries (attachments and staging) | Accuracy Upper Incisor Torque > 10° Invisalign with horizontal ellipsoid attachments vs Invisalign with power bridges: 51.5% SD 0.2 vs. 49.1%SD 0.2 Premolar derotation > 10° Invisalign with optimized rotation attachment vs Invisalign without auxiliaries: 37.5% SD 0.3 vs. 42.4% SD 0.3 Upper molar distalization > 1.5 mm Invisalign with horizontal beveled gingival attachment vs Invisalign without auxiliaries: 88.4% SD 0.3 vs. 86.9% SD 0.16 The overall accuracy Upper incisor torque > 10°: 42% Premolar derotation > 10°: 40% Upper molar distalization > 1.5 mm: 87% |
Zhou et al. 2020 [21] | Retrospective study | 20 participants Aged 20–45 years (mean 28.5 SD 6.3) | Accuracy of transverse width measured at: - Level of canine tip -First premolar tip -Second premolar tip -First molar tip Maxillary basal bone width variations Maxillary alveolar bone (buccal and palatal ridge crest) width variation Difference of maxillary first molar tipping | ClinCheck® software (planned vs achieved) | Transverse expansion -Canine 1.44 SD 0.60 mm -First premolar 1.74 SD 0.84 mm -Second premolar 1.57 SD 0.96 mm Predictability of transverse expansion -Canine tip: 0.33 SD 0.26 mm (79.75%) -First premolar tips: 0.53 SD 0.45 mm (76.1%) -Second premolar gingival: 0.65 SD 0.76 (73.3%) -First molar tip 0.74 SD 0.73 (68.3%) Difference in the basal bone width 0.04 SD 0.18 mm Maxillary alveolar bone arch width - Buccal ridge crest: 0.87 SD 0.63 mm - Palatal ridge crest 0.75 SD 0.80 mm Maxillary first molar tipping 2.07 SD 3.3 |
Solano-Mendoza et al., 2017 [22] | Retrospective study | 116 participants Mean age 36.6 (SD 11.5) | Accuracy of transverse width measured at: - level of canine tip and gingival margin -first premolar tip and gingival margin -second premolar tip and gingival margin -first molar tip and gingival margin | ClinCheck® software (planned vs achieved) | Predictability -Canine tip: 94.2% - Canine gingival margin: 76.5% -First premolar tip: 89.7% -First premolar gingival margin: 84.2% -Second premolar tip: 92.1% -Second premolar gingival margin: 88.9% -First molar tip: 88.6% -First molar gingival margin: 87.7% |
Riede et al., 2021 [23] | Retrospective study | 30 participants Aged 13–50 years | Accuracy of expansion | ClinCheck® software (planned vs achieved) | Transverse expansion -Canine tip: 0.4 SD 0.3 mm -Canine gingival margin: 0.45 SD 0.3 mm -First premolar tip: 0.5 SD 0.25 mm -First premolar gingival margin: 0.4 SD 0.2 mm -Second premolar tip: 0.5 SD 0.3 mm -Second premolar gingival margin: 0.5 SD 0.45 mm -First molar tip: 0.5 SD 0.35 mm -First molar gingival margin: 0.5 SD 0.3 mm -Distobuccal cusp tip in first and second molars 2.9 SD 1.9° and 2.9 SD 2.4°, respectively Participants achieving the width variation planned by ClinCheck software for each site of the following upper maxillary teeth: -Canine cusp (46.6%) -Canine gingival margin (28.3%) -First premolar cusp (41.7%) - First premolar gingival margin (46.7%) -Second premolar cusp (50%) -Second premolar gingival margin (56.7%1) - First molar cusp (40%) -First molar gingival margin (50%) |
Gu et al., 2017 [16] | Case–control | 96 participants Mean age 22.1 SD 7.9 and 26 SD 9.7 | -Peer Assessment Rating (PAR) Index -Treatment duration | Invisalign® vs conventional fixed appliances | -Both intervention and control groups achieved a statistically significant clinical improvement of PAR index (> 30% of score reduction) -Fixed orthodontic appliance was better than Invisalign in resolving malocclusion based on PAR index scores -Fixed orthodontic appliance was more effective than Invisalign in reducing the mean percentage of PAR index -Invisalign treatment was faster than fixed orthodontic appliance: (13.35 vs 19.08 months) |
Grünheid et al., 2017 [24] | Retrospective study | 30 participants Age 21.6 SD 9.8 | Accuracy of: -Mesial-distal -Facial-lingual - Occlusal-gingival -Tip -Torque -Rotation | ClinCheck® software (planned vs achieved) | Accuracy Mesial-distal Maxilla -Central incisor: − 0.06 SD 0.4 mm -Lateral incisor: − 0.14 SD 0.39 mm -Canine: − 0.11 SD 0.51 mm -First premolar: 0.02 SD 0.47 mm -Second premolar: 0.19 SD 0.65 mm -First molar: 0.27 SD 0.30 mm -Second molar: 0.07 SD 0.81 Mandible -Central incisor: 0.12 SD 0.44 mm -Lateral incisor: − 0.8 SD 0.62 -Canine: − 0.11 SD 0.72 mm -First premolar: 0.02 SD 0.44 mm -Second premolar: 0.13 SD 0.57 mm -First molar 0.12 SD 0.34 mm -Second molar 0.02 SD 0.50 mm Facial-lingual Maxilla -Central incisor: − 0.45 SD 0.64 mm -Lateral incisor: 0.01 SD 0.66 mm -Canine: 0.11 SD 0.60 mm -First premolar: 0.15 SD 0.53 mm -Second premolar: 0.20 SD 0.63 mm -First molar: 0.23 SD 0.62 mm -Second molar: 0.30 SD 0.79 Mandible -Central incisor: 0.11 SD 0.56 mm -Lateral incisor: − 0.01 SD 0.51 mm -Canine: − 0.26 SD 0.49 mm -First premolar: 0.05 SD 0.62 mm -Second premolar: 0.09 SD 0.59 mm -First molar: − 0.08 SD 0.52 mm -Second molar − 0.017 SD 0.39 mm Occlusal-gingival Maxilla -Central incisor: − 0.30 SD 0.28 mm -Lateral incisor: − 0.03 SD 0.26 mm -Canine: − 0.02 SD 0.24 mm -First premolar: 0.06 SD 0.19 mm -Second premolar: 0.01 SD 0.22 mm -First molar: − 0.02 SD 0.14 mm -Second molar: − 0.13 SD 0.29 mm Mandible -Central incisor: − 0.14 SD 0.21 mm -Lateral incisor: − 0.10 SD 0.22 mm -Canine: − 0.01 SD 0.21 mm -First premolar: 0.09 SD 0.24 mm -Second premolar: 0.04 SD 0.21 mm -First molar: − 0.01 SD 0.15 mm -Second molar: 0.047 SD 0.16 mm Tip Maxilla -Central incisor: − 0.42 SD 1.57° -Lateral incisor: 0.35 SD 2.36° -Canine: 0.31 SD 2.24° -First premolar: − 0.18 SD 1.96° -Second premolar: − 0.82 SD 3.63° -First molar: − 1.06 SD 1.4° -Second molar: 0.41 SD 5.18° Mandible -Central incisor: − 0.36 SD 1.81° -Lateral incisor: 0.51 SD 2.75° -Canine: 0.39 SD 3.11° -First premolar: 0.16 SD 2.04° -Second premolar: − 0.55 SD 2.55° -First molar: − 0.38 SD 1.35° -Second molar: 1.07 SD 3.06° Torque Maxilla -Central incisor: 1.75 SD 2.86° -Lateral incisor 0.08 SD 2.93° -Canine: − 0.048 SD 2.55° -First premolar: − 0.74 SD 2.40° -Second premolar: − 1.18 SD 3.27° -First molar: − 1.45 SD 2.37° -Second molar: − 2.13 SD 4.19° Mandible -Central incisor: − 0.66 SD 2.61° -Lateral incisor: − 0.29 SD 2.34° -Canine: − 1.60 SD 2.04° -First premolar: − 0.60 SD 2.53° -Second premolar: − 0.74 SD 3.05° -First molar: − 0.85 SD 2.41° -Second molar: − 1.09 SD 2.13° Rotation Maxilla -Central incisor: − 0.33 SD 2.80° -Lateral incisor: 0.70 SD 3.23° -Canine: 0.19 SD 2.31° -First premolar: − 0.48 SD 1.48° -Second premolar: − 0.70 SD 1.95° -First molar: − 0.52 SD 1.58° -Second molar: 0.06 SD 2.20° Mandible -Central incisor: − 0.60 SD 1.71° -Lateral incisor: − 0.99 SD 2.28° -Canine: 0.88 SD 3.14° -First premolar: − 1.71 SD 2.91° -Second premolar: − 0.88 SD 3.86° -First molar: − 0.30 SD 1.07° -Second molar 0.29 SD 2.66° Statistically significant discrepancy with ClinCheck® prevision involves -Upper central incisors (facial-lingual and occlusal-gingival movements) -Upper second premolar and upper first molar (mesial-distal and facial-lingual movements) -Upper second molar (occlusal-gingival movements) -Lower central and lateral incisors (occlusal-gingival movements) -Upper central incisor (torque) -Upper first molar (tip and torque) -Second lower premolar and molar (torque) -Lower lateral incisor (rotation) -Lower canine (torque and rotation) -First and second lower premolars (rotation) -Lower second molar (tip) |
Houili et al., 2020 [12] | Prospective clinical study | 38 participants Mean age 36 years | Accuracy -Mesial-distal crown tip -Buccal-lingual crown tip -Extrusion -Intrusion -Mesial-distal rotation | ClinCheck® software (planned vs achieved) | Accuracy The mean accuracy of Invisalign for all tooth movements was 50% -Rotation (46%) -Buccal-lingual crown tip (56%) -Mesial rotation of the mandibular first molar (28%) -Intrusion of the maxillary central incisor (33%) -Intrusion of the mandibular incisors (35%) -Buccal crown tip of the maxillary second molar (35%) -Distal rotation of the maxillary canine (37%) -Extrusion of the mandibular second molar (37%) -Distal crown tip of the mandibular second molar (50%) -Intrusion of the mandibular second molar (51%) -Mesial rotation of the maxillary canine (52%) -Extrusion of the maxillary central incisor (56%) -The lingual crown tip of the maxillary second molar (61%) - Buccal crown tip of the maxillary second premolar (61%) -Distal crown tip of the maxillary second molar (63%) -Labial crown tip of the maxillary lateral incisor (70%) -Buccal crown tip of the mandibular second premolar (70%) |
Kassas et al., 2013 [17] | Retrospective study | 31 participants Mean age 35.2 ± 13.2 years | Model Grading System (MGS) of the American Board of Orthodontics: -Alignment -Marginal ridges -Buccolingual inclination -Occlusal contacts -Occlusal relations -Overjet -Interproximal contacts | The mean scores of all of the MGS categories were improved after treatment, with the exceptions of the occlusal contacts and occlusal relationships categories The improvements were statistically significant in scores: -Alignment category: 15.16 SD 5.00 vs. 6.00 SD 3.78 -Buccolingual inclination category: 7.00 SD 3.14 vs. 6.26 SD 3.58 -Total MGS score: 45.03 SD 7.47 vs. 35.87 SD 9.36 Using the ABO criteria -1 case (3%) received a passing score -22 cases (71%) failed -8 cases (26%) were considered borderline | |
Pavoni et al., 2011 [25] | 40 participants Mean age Self-ligating 15 years Mean age Invisalign® Group 18 years | Transversal expansion: -Intercanine width (lingual) -Intercanine width (cusp) -First interpremolar width (lingual) -First interpremolar width (fossa) -Second interpremolar width (lingual) -Second interpremolar width (fossa) -Intermolar width (lingual) -Intermolar width (fossa) -Arch depth -Arch perimeter | Self-ligating vs Invisalign® | Self-ligating group -Intercanine width (cusp) showed a significant increase from T1 to T2: 3.15 mm -First interpremolar widths (lingual and cusp) had significant increases of 3.40 mm and 2.45 mm, respectively -Second interpremolar widths (lingual and cusp), with significant increases of 2.50 mm and 2.15 mm, respectively Invisalign® group -Second interpremolar width at the fossa point (0.45 mm) -Intermolar widths at the fossa (0.50 mm) Significant difference was found between the 2 groups for the intercanine widths, the change at the cusp was significantly larger in the self-ligating group (2.65 mm) The comparison between the two groups of the first interpremolar measurements showed an improvement in the self-ligating subjects significantly bigger at the lingual point (2.30 mm), and at the cusp (3.35 mm), similar to the second interpremolar widths (lingual and cusp), with a significant increase of 1.85 mm and 2.05 mm, respectively | |
Drake et al., 2012 [26] | Prospective single-center clinical trial | 15 new participants (weekly aligner group) | -ΔU1(x) refers to the distance between lines drawn through the midpoint of the incisal edges of the superimposed target tooth perpendicular to the A-P axis (the plane of prescribed tooth movement) - ΔU1(s) is the length of the line connecting the midpoint of the incisal edges of the superimposed target tooth - ΔApex refers to the length of a line connecting the change in apex of the superimposed target tooth - Rotation angle is the angle created by the intersection of lines drawn from the midpoint of the incisal edge to the apex of the target tooth. The apex of this angle is considered the center of rotation - Tooth length refers to the distance from the midpoint of the incisal edge to the apex of the target tooth from the initial X-ray - Crown length is the portion of the tooth length that is coronal to the bone - Bone to C-rot. is the section of tooth length between the center of rotation and a line connecting the most coronal aspect of the faciolingual crestal bone - ΔU1(o) refers to the A-P change in the midpoint of the superimposed incisal edge of the opposite central incisor, the one that was not the target tooth - ΔU1(t) refers to the distance between the midpoint of the superimposed incisal edge of the contralateral central incisor, to the midpoint of the incisal edge of the target tooth | 37 participants previously collected (biweekly aligner control group) | No overall difference in OTM (orthodontic tooth movement) was detected between the groups, with mean total OTM of 1.11 mm SD 0.30 and 1.07 mm SD 0.33 for the weekly aligner and biweekly control groups, respectively Also, no difference was detected in the weekly OTM of the weekly aligner versus biweekly control groups overall (P = 0.812) or between any 2-week prescription cycle for the weekly aligner and biweekly control groups However, 4.4 times more OTM occurred during the first week than the second week of aligner wear (P < 0.001) for the combined groups, considering all 2-week periods |
Ravera et al., 2016 [15] | Multicenter retrospective study | 20 participants Mean age 29.73 years | Bodily maxillary molar distalization | ClinCheck® software (planned vs achieved) | Bodily distalization -Upper first molar: 2.25 mm -Upper second molar: 2.52 mm |
Duncan et al., 2016 [27] | A retrospective chart review | 61 participants | Arch Expansion Interproximal reduction Lowe incisor position and angulation | ClinCheck® software (planned vs achieved) | Differences in mean (T0-T1) Mild crowding OVJ: 0.73 mm Moderate crowding OVJ: 0.73 mm OVB: 0.68 mm Severe crowding OVJ:1.32 mm L1-NB: − 4.70° L1-NB: − 1.55 mm L1-MPA: − 3.94° L1-APog: − 4.82° L1-APog: − 1.74 mm |
Grunheid et al., 2016 [28] | Retrospective cohort study | 60 participants Mean age 25/26 years | -Buccolingual inclination of the mandibular canines -Intercanine distance | Invisalign® vs conventional fixed appliances | Difference (T2-T1) Clear aligner Inclination: 0.7 SD 2.5° Distance: 0.7 SD 1.5 mm Fixed appliance Inclination: − 1.9 SD 5.1° Distance: − 0.1 SD 2.4 mm |
Khosravi et al., 2017 [13] | Retrospective study | 120 participants: -68 with a normal overbite -40 with deepbite -12 with openbite Mean age 18 years or older | Overbite changes | No control group | Normal overbite -Proclination of maxillary incisors (U1-NA): 0.7° and (L1-NB) 0.6° - Anterior facial height: + 0.7 mm -Mandibular plane angle: + 0.4° Deep bite -1.5-mm median opening of the overbite -Proclination of the mandibular incisors and intrusion of the maxillary incisors -Extrusion of mandibular first and second molars: 0.5 mm on average -Proclination of the mandibular incisors was the main mechanism of bite opening Open bite -A median deepening of 1.5 mm -Extrusion of the maxillary and mandibular incisors: (U1-PP) 0.9 mm and (L1-MP) 0.8 mm |
Chisari et al., 2014 [29] | Prospective single-center clinical trial | 30 participants Ages 19 to 64 years old | Assessment of the impacts of age, sex, root length, bone levels, and bone quality on orthodontic tooth movement | No control group | -The rate of movement decreases from ages 18 to 35 years -A slightly increasing rate from ages 35 to 50 and a decreasing rate from ages 50 to 70 -The correlation was significant between the percentage of the goal achieved and the cone-beam computed tomography superimposed linear measures of tooth movement -A significant negative correlation was found between tooth movement and the measurement apex to the center of rotation, but bone quality, as measured by fractal dimension, was not correlated with movement |
Hennessy et al., 2016 [30] | Prospective clinical trial | 44 participants Mean age 26.5 years SD 7.7 | Mandibular incisor proclination | Invisalign® vs conventional fixed appliances | Mandibular incisor proclination -Fixed appliances: 5.3° SD 4.3° -Clear aligners: 3.4° SD 3.2° |
Charalampakis et al., 2018 [10] | Retrospective study | 20 subjects Mean age 37 years | -Horizontal displacements - Vertical displacements - Intercanine and interpremolar widths -Mesiodistal rotations | ClinCheck® software (planned vs achieved) | Horizontal displacements Median difference (predicted-achieved) -Maxillary central incisors horizontal (mm): 0.25 -Maxillary canines horizontal (mm): 0.20 Vertical displacements Median difference (predicted-achieved) -Maxillary central incisors intrusion (mm): 1.50 -Maxillary lateral incisors intrusion (mm): 1.10 - Mandibular incisors intrusion (mm): 0.80 -Mandibular canines vertical (mm): 0.30 - Intercanine and interpremolar widths Median difference (predicted-achieved) -Maxillary intercanine width (mm): 0.45 Mesiodistal rotations Median difference (predicted-achieved) -Maxillary central incisors rotation (°): 2 - Maxillary lateral incisors rotation (°): 1.85 - Maxillary canines rotation (°): 3.05 - Maxillary premolars rotation (°): 0.90 - Mandibular incisors rotation (°): 1.85 - Mandibular canines rotation (°): 2.45 - Mandibular premolars rotation (°): 1.90 |
Buschang et al., 2015 [31] | Prospective clinical study | 27 participants No age indication | OGS scores: -Alignment -Marginal ridges -Buccolingual inclination -Occlusal contacts -Occlusal relations -Overjet -Interproximal contacts | ClinCheck® software (planned vs achieved) | -Differences were greatest for alignment, marginal ridges, and occlusal contacts -Differences for occlusal relations were also highly significant |
Dai et al., 2019 [32] | Retrospective study | 30 participants Mean age 19.4 ± 6.3 years | First premolar extractions with Invisalign: Achieved vs predicted movements of maxillary first molars and central incisors | ClinCheck® software (planned vs achieved) | Difference (predicted and achieved) Central incisors U1_Torque: − 5.16 SD 5.92° U1_LLT: 2.12 SD 1.51 mm U1_OGT: − 0.50 SD 1.17 mm Maxillary first molars U6_Angulation: 5.86 SD 3.51° U6MC_MDT: 2.26 SD 1.58 mm U6DC_ MDT: 2.31 SD 1.67 mm U6MC_OGT: 0.61 SD 0.89 mm U6DC_OGT: 0.01 SD 0.91 mm |
Sfrondrini et al., 2018 [33] | Retrospective study | 75 participants: -25 aligners -25 conventional fixed appliance -25 self-ligating appliance | Control of upper incisor torque: -11^SnaSnp -11^Ocl -I + TVL | Invisalign® vs -Conventional fixed appliance - Self-ligating appliance | 11^SnaSnp Conventional: 6.11° SD 3.91 Self-ligating: 5.64° SD 3.27 Aligner: 5.13° SD 3.23 11^Ocl Conventional: 6.88° SD 4.28 Self-ligating: 5.17° SD 3.10 Aligner: 4.60° SD 3.46 I + TVL Conventional: 1.56 mm SD 0.47 Self-ligating: 1.62 mm SD 0.66 Aligner: 1.47 mm SD 0.57 |
Qualitative synthesis of the included studies
Study | Selection (max 1 star for each of the 4 items) | Comparability (max 2 stars for the 1 item) | Outcome (max 1 star for each of the 3 items) | Total stars | |||||
---|---|---|---|---|---|---|---|---|---|
Buschang 2015 [31] | * | * | * | * | * | * | * | * | 8/9 |
Charalampakis 2018 [10] | * | * | * | * | ** | * | * | * | 9/9 |
Chisari 2014 [29] | * | * | * | * | * | * | 6/9 | ||
Dai 2019 [32] | * | * | * | * | ** | * | * | * | 9/9 |
Drake 2012 [26] | * | * | * | * | * | * | * | * | 8/9 |
Duncan 2016 [27] | * | * | * | * | * | * | * | * | 8/9 |
Grünheid 2016 [28] | * | * | * | * | * | * | * | * | 8/9 |
Grünheid 2017 [24] | * | * | * | * | * | * | * | * | 8/9 |
Gu 2017 [16] | * | * | * | * | ** | * | * | * | 9/9 |
Haouili 2020 [12] | * | * | * | * | ** | * | * | * | 9/9 |
Hennessy 2016 [30] | * | * | * | * | * | * | * | 7/9 | |
Houle 2017 [28] | * | * | * | * | * | * | 6/9 | ||
Kassas 2013 [17] | * | * | * | * | ** | * | * | * | 9/9 |
Khosravi 2017 [13] | * | * | * | * | ** | * | * | * | 9/9 |
Krieger 2012 [20] | * | * | * | * | * | * | 6/9 | ||
Lanteri 2018 [14] | * | * | * | * | ** | * | * | * | 9/9 |
Morales-Burruezo 2020 [18] | * | * | * | * | * | * | * | * | 8/9 |
Pavoni 2011 [25] | * | * | * | * | * | * | 6/9 | ||
Ravera 2016 [15] | * | * | * | * | ** | * | * | * | 9/9 |
Riede 2021 [23] | * | * | * | * | * | * | * | 7/9 | |
Sfondrini 2018 [33] | * | * | * | * | * | * | * | * | 8/9 |
Simon 2014 [11] | * | * | * | * | * | * | 6/9 | ||
Solano-Mendoza 2016 [22] | * | * | * | * | * | * | * | * | 8/9 |
Zhou 2020 [21] | * | * | * | * | * | * | * | 7/9 |
Clinical findings
Transverse changes
Sagittal movements
Vertical movements
Intrusion
Extrusion
Rotations
Buccolingual movements
Alignment
Accuracy
Aligners’ change
Discussion
Limitations
Conclusions
-
-Expansion of the upper arch occurs through more coronal tipping than bodily movement. The predictability of coronal expansion decreases moving towards the posterior sector.
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-The predictability in the deepbite correction is reduced, thus requiring greater attention in the planning of the ClinCheck® software. It occurs mainly through the proclination of the lower incisors (relative intrusion).
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-Differently, in the treatment of open bite, the resolution occurs through a combination of extrusion of the incisors and lingual crown tip (relative extrusion).
-
-In cases of crowding, the correct management involves the combination of expansion and IPR to reduce the incisal proclination.
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-In sagittal movements, it is advisable not to go beyond the 2–3 mm distalization of the molars.
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-At the end of the treatment, the incisal position is almost always more occlusal than expected, the rotations of the premolars and the incisal torque are not completely resolved.