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Each row is one question a systematic review asked: who, what, compared with what, and which outcome, with the effect it found and how certain that is. Words match anywhere in the field.
830 questions in 43 reviews · Orthodontics
current versionsNo studies 186 · 22.4%Ungraded 410 · 49.4%Very low 122 · 14.7%Low 79 · 9.5%Moderate 30 · 3.6%High 3 · 0.4%
Ungraded means an effect was reported without a GRADE rating; it is not a gap. No studies means the review found nothing to answer the question. The six categories are a display order, not a score.
| Question | Effect | Evidence | Status / GRADE |
|---|---|---|---|
Sealant or coating agent (with or without fluoride release) applied to teeth with fixed appliances vs No sealant (untreated control teeth) White spot lesions assessed by laser fluorescence (DIAGNOdent) · Patients of any age (11-40 years) receiving comprehensive/fixed orthodontic treatment with fixed appliances Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel… (2021) | Laser fluorescence (DIAGNOdent) was assessed in 3 studies comparing sealant vs no sealant, but meta-analysis could not be performed because results were presented parametrically or non-parametrically without the… | 3 studies | Ungraded |
Fluoride-releasing compomer bonding agent vs Compomer bonding agent without fluoride release Incidence of new white spot lesions by visual-tactile assessment · Patients receiving comprehensive fixed orthodontic treatment · 1 to 24 months, Compomer-based bonding agents Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel… (2021) | RR 0.71 [0.46, 1.11] | 2 studies · 400 participants | Ungraded |
Haas expander anchored on deciduous second molars vs Haas expander anchored on permanent first molars Molar expansion · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… · after 5-month retention period Orthodontic treatment for posterior crossbites (2021) · Cochrane | Ugolini 2015: deciduous 4.3 mm vs permanent 5.8 mm; P<0.01 (favours permanent-molar anchorage) | 1 study | Ungraded |
Hyrax with conventional expansion screw vs Hyrax with NiTi memory expansion screw Molar expansion · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… · after 6-month retention period Orthodontic treatment for posterior crossbites (2021) · Cochrane | Halicioglu 2014: conventional Hyrax 8.41 (SD 2.09) mm vs NiTi Hyrax 8.94 (SD 1.73) mm; no statistically significant differences for any outcome | 1 study | Ungraded |
Clear aligners (Invisalign / thermoformed aligners) vs Fixed appliances S. mutans presence · Adolescents/teenagers undergoing orthodontic treatment · 1 month, Adolescents Impact of Aligners and Fixed Appliances on Oral Health during Orthodontic Treatment: A Systematic Review and… (2021) | RR 0.86 [0.64, 1.14] | 1 study | Ungraded |
Self-ligating brackets vs Conventional brackets Amount of crowding (lower incisor crowding) at 10 weeks · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · 10 weeks Orthodontic treatment for crowded teeth in children (2021) · Cochrane | MD -0.40 [-0.93, 0.13] | 1 study · 60 participants | Very low |
Intervention NR Initiation of white spot lesions (WSL), visual-tactile assessment · Sensitivity (glass ionomer cement vs resin adhesive, excluding high risk-of-bias studies) Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel… (2021) | RR 1.02 [0.82, 1.27] | NR | Ungraded |
Extraction of the primary (baby) canine (single primary tooth extraction) vs No extraction (non-intervention control) Incidence of successfully erupted PDC that were favourably positioned · Young people aged 9 to 14 years diagnosed with one or both palatally displaced permanent maxillary canines (PDC) Interventions for promoting the eruption of palatally displaced permanent canine teeth, without the need for… (2021) · Cochrane | Favourable position of the erupted PDC was not reported for this comparison. | 0 studies | No studies |
Clear aligners (Invisalign / thermoformed aligners) vs Fixed appliances S. mutans presence (CFU > 10^5) · Adults undergoing orthodontic treatment · 6 months, Adults Impact of Aligners and Fixed Appliances on Oral Health during Orthodontic Treatment: A Systematic Review and… (2021) | RR 0.22 [0.10, 0.51] | 2 studies · 140 participants | Low |
Extraction of the primary (baby) canine (single primary tooth extraction) vs No extraction (non-intervention control) Overall treatment time wearing orthodontic appliances · Young people aged 9 to 14 years diagnosed with one or both palatally displaced permanent maxillary canines (PDC) Interventions for promoting the eruption of palatally displaced permanent canine teeth, without the need for… (2021) · Cochrane | no estimate extracted | 0 studies | No studies |
Haas expander anchored on deciduous second molars vs Haas expander anchored on permanent first molars Canine expansion · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… · after 5-month retention period Orthodontic treatment for posterior crossbites (2021) · Cochrane | Ugolini 2015: deciduous 4.2 mm vs permanent 3.3 mm; P<0.01 (more stable anterior expansion with deciduous anchorage) | 1 study | Ungraded |
Self-ligating brackets (Damon System) vs Fixed tooth-borne Hyrax expander Crossbite correction · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… Orthodontic treatment for posterior crossbites (2021) · Cochrane | Nam 2020: Damon 41/41 vs Hyrax 41/41; NS (no difference in crossbite correction; greater transverse molar/premolar expansion with Hyrax) | 1 study · 82 participants | Ungraded |
Intervention NR Initiation of white spot lesions (WSL), visual-tactile assessment · Sensitivity (coating with vs without fluoride release, excluding parallel-arm studies) Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel… (2021) | RR 0.82 [0.66, 1.02] | NR | Ungraded |
Double primary (canine and first molar) tooth extraction vs Single primary (canine) tooth extraction Incidence of eruption of the PDC into the mouth · Young people aged 9 to 14 years diagnosed with one or both palatally displaced permanent maxillary canines (PDC) · 12 months Interventions for promoting the eruption of palatally displaced permanent canine teeth, without the need for… (2021) · Cochrane | RR 0.27 [0.04, 2.08] | 1 study · 23 participants | Ungraded |
Intervention NR Initiation of white spot lesions (WSL), visual-tactile assessment · Sensitivity (sealant vs no sealant, excluding high risk-of-bias studies) Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel… (2021) | RR 0.85 [0.66, 1.10] | NR | Ungraded |
Fluoride-releasing resin-based sealant vs Non-fluoride resin-based sealant Initiation of white spot lesions (WSL), visual-tactile assessment · Patients of any age (11-40 years) receiving comprehensive/fixed orthodontic treatment with fixed appliances · 1-24 months follow-up, Resin-based sealants Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel… (2021) | RR 0.71 [0.35, 1.43] | 2 studies · 644 participants | Ungraded |
Extraction of lower deciduous canines vs No active treatment (control) Amount of crowding (lower incisor crowding, change) at 1-2 years · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · 1 to 2 years Orthodontic treatment for crowded teeth in children (2021) · Cochrane | MD -4.76 [-6.24, -3.28] | 1 study · 83 participants | Very low |
Bonded Minne appliance (slow maxillary expansion) vs Banded Minne appliance (slow maxillary expansion) Stability of crossbite correction (relapse of molar expansion) · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… · 24 weeks after completion of expansion Orthodontic treatment for posterior crossbites (2021) · Cochrane | Bonded Minne 2.3 mm (SD 0.8) vs Banded Minne 2.5 mm (SD 0.6); P=NS | 1 study | Ungraded |
Resin infiltration vs Fluoride varnish Optical/esthetic improvement (DIAGNOdent reading) · Patients (mainly children) with white spot lesions (WSL) · 3 to 6 months, Mild lesions, DIAGNOdent score <=14 (Ciftci et al. 2018; Giray et al. 2018) Efficacy of resin infiltration to mask post-orthodontic or non-post-orthodontic white spot lesions or… (2021) | MD 3.65 [0.82, 6.48] | 2 studies · 172 participants | Ungraded |
Fixed tooth-bone-borne expansion vs Fixed tooth-borne expansion (Hyrax) Crossbite correction · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… · Children Orthodontic treatment for posterior crossbites (2021) · Cochrane | RR 1.02 [0.92, 1.12] | 3 studies · 120 participants | Low |
Clear aligners (Invisalign / thermoformed aligners) vs Fixed appliances Full-mouth bleeding score (FMBS) · Adolescents/teenagers undergoing orthodontic treatment · 12 months, Adolescents Impact of Aligners and Fixed Appliances on Oral Health during Orthodontic Treatment: A Systematic Review and… (2021) | MD -20.44 [-22.98, -17.90] | 1 study | Ungraded |
Resin infiltration vs Fluoride varnish Optical/esthetic improvement (DIAGNOdent reading) · Patients (mainly children) with white spot lesions (WSL) · 3 to 6 months, Severe lesions, DIAGNOdent score >14 (Gozetici et al. 2019) Efficacy of resin infiltration to mask post-orthodontic or non-post-orthodontic white spot lesions or… (2021) | MD 13.15 [3.98, 22.32] | 1 study · 40 participants | Ungraded |
Sealant or coating agent (with or without fluoride release) applied to teeth with fixed appliances vs No sealant (untreated control teeth) Initiation of white spot lesions (WSL), visual-tactile assessment · Patients of any age (11-40 years) receiving comprehensive/fixed orthodontic treatment with fixed appliances · 3-27 months follow-up Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel… (2021) | RR 0.70 [0.53, 0.93] | 6 studies · 2314 participants | Very low |
Lower lip bumper vs No active treatment (control) Lower molars to mandible at 6 months · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · 6 months Orthodontic treatment for crowded teeth in children (2021) · Cochrane | MD -0.91 [-1.58, -0.24] | 1 study · 34 participants | Ungraded |
Resin infiltration vs Untreated control (natural remineralization) Optical/esthetic improvement (visual-tactile assessment) · Patients with post-orthodontic white spot lesions (WSL) · 4 weeks to 6 months, Spectroscopy delta-E (Knosel et al. 2013) Efficacy of resin infiltration to mask post-orthodontic or non-post-orthodontic white spot lesions or… (2021) | SMD 0.63 [0.26, 1.01] | 1 study · 115 participants | Ungraded |
Vibrational appliance with fixed appliances vs Fixed appliances only / no vibrational appliance (control) Harms (orthodontically-induced inflammatory root resorption) · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · end of alignment Orthodontic treatment for crowded teeth in children (2021) · Cochrane | Using a vibrational appliance did not affect amount of root resorption vs control (Woodhouse 2015; 72 participants analysed). Narrative; no pooled estimate. | 1 study · 72 participants | Ungraded |
Self-ligating brackets vs Conventional brackets Time for ligation (seconds, to ligate six brackets) · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · during treatment Orthodontic treatment for crowded teeth in children (2021) · Cochrane | MD -78.8 [-81.86, -75.74] | 1 study · 60 participants | Ungraded |
Bone-borne expansion vs Fixed tooth-borne expansion (Hyrax) Molar expansion (inter-molar distance) · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… · Children and adolescents Orthodontic treatment for posterior crossbites (2021) · Cochrane | MD -0.14 [-0.85, 0.57] | 2 studies · 81 participants | Low |
Coating material (bonding material or sealant) WITH fluoride release vs Coating material WITHOUT fluoride release White spot lesions assessed by laser fluorescence (DIAGNOdent) · Patients of any age (11-40 years) receiving comprehensive/fixed orthodontic treatment with fixed appliances Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel… (2021) | Laser fluorescence (DIAGNOdent) was assessed in 3 studies comparing coating with vs without fluoride release, but meta-analysis could not be performed (results reported using incompatible continuous/categorical formats… | 3 studies | Ungraded |
Fixed bonded Hyrax appliance followed by U-bow activator therapy vs No treatment Molar expansion · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… · 12 months after start of treatment Orthodontic treatment for posterior crossbites (2021) · Cochrane | U-bow activator 5.1 mm vs untreated 0.8 mm; P<0.001 (no SD reported); significant in favour of treatment | 1 study · 66 participants | Ungraded |
Semi-rapid maxillary expansion vs Rapid maxillary expansion Canine expansion · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… Orthodontic treatment for posterior crossbites (2021) · Cochrane | MD 0.36 [-0.64, 1.36] | 1 study · 35 participants | Ungraded |
Lacebacks with fixed appliances vs Fixed appliances only (control) Amount of crowding (change) at 6 months · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · 6 months Orthodontic treatment for crowded teeth in children (2021) · Cochrane | MD -0.33 [-5.90, 5.24] | 1 study · 62 participants | Very low |
Removable tooth-borne expansion (expansion plate) vs Observation (no treatment) Molar expansion (inter-molar distance) · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… · Children (7 to 11 years) Orthodontic treatment for posterior crossbites (2021) · Cochrane | MD 3.30 [2.88, 3.73] | 3 studies · 145 participants | Moderate |
Extraction of the primary (baby) canine (single primary tooth extraction) vs No extraction (non-intervention control) Costs / cost-effectiveness · Young people aged 9 to 14 years diagnosed with one or both palatally displaced permanent maxillary canines (PDC) Interventions for promoting the eruption of palatally displaced permanent canine teeth, without the need for… (2021) · Cochrane | The study did not report cost-effectiveness. | 0 studies | No studies |
Copper nickel-titanium archwire vs Nickel-titanium archwire Harms (discomfort) · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · after archwire change Orthodontic treatment for crowded teeth in children (2021) · Cochrane | No difference in overall discomfort levels between copper NiTi and NiTi archwire sequences (Ong 2011, 7-point Likert). Narrative; no pooled estimate. | 1 study | Ungraded |
Clear aligners (Invisalign / thermoformed aligners) vs Fixed appliances Simplified plaque index (s-PI) · Adolescents/teenagers undergoing orthodontic treatment · 1 month, Adolescents Impact of Aligners and Fixed Appliances on Oral Health during Orthodontic Treatment: A Systematic Review and… (2021) | MD -14.78 [-16.74, -12.82] | 1 study | Ungraded |
Extraction of third molars (wisdom teeth) vs No active treatment (control) Size of the lower jaw (arch length, change) · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · 5 years Orthodontic treatment for crowded teeth in children (2021) · Cochrane | MD 1.03 [0.56, 1.50] | 1 study · 77 participants | Ungraded |
Fixed Hyrax maxillary expander vs Fixed fan-type maxillary expander Molar expansion · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… · post-treatment 3 weeks Orthodontic treatment for posterior crossbites (2021) · Cochrane | Gopalakrishnan 2017: Hyrax 8.00 (SD 2.19) mm vs fan-type 1.83 (SD 0.41) mm; P<0.001 (greater intermolar expansion with Hyrax) | 1 study · 12 participants | Ungraded |
Any orthodontic (non-surgical) treatment to correct posterior crossbite or expand the top teeth vs No treatment or another orthodontic treatment Signs and symptoms of temporomandibular joint dysfunction · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… Orthodontic treatment for posterior crossbites (2021) · Cochrane | no estimate extracted | 0 studies | No studies |
Lower lingual arch vs No active treatment (control) Lower incisors to mandible at 1 year · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · 1 year Orthodontic treatment for crowded teeth in children (2021) · Cochrane | MD 3.01 [1.71, 4.31] | 1 study · 30 participants | Ungraded |
Intervention NR Initiation of white spot lesions (WSL), visual-tactile assessment · Sensitivity (coating with vs without fluoride release, excluding high risk-of-bias studies) Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel… (2021) | RR 0.83 [0.67, 1.04] | NR | Ungraded |
Extraction of lower deciduous canines vs No active treatment (control) Size of the lower jaw (arch length, change) at 1 year · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · 1 year Orthodontic treatment for crowded teeth in children (2021) · Cochrane | MD -2.73 [-3.69, -1.77] | 1 study · 83 participants | Ungraded |
Clear aligners (Invisalign / thermoformed aligners) vs Fixed appliances Lesion area (decalcification area, pixels) · Adults undergoing orthodontic treatment · 3 months, Adults Impact of Aligners and Fixed Appliances on Oral Health during Orthodontic Treatment: A Systematic Review and… (2021) | MD 80.50 [60.52, 100.48] | 1 study | Ungraded |
Bonded Minne appliance (slow maxillary expansion) vs Banded Minne appliance (slow maxillary expansion) Molar expansion · Children and adults with a posterior crossbite, without a Class III skeletal relationship, cleft lip or palate (or… · 7 to 15 weeks after start of treatment Orthodontic treatment for posterior crossbites (2021) · Cochrane | Bonded Minne 7.9 mm (SD 1.5) vs Banded Minne 8.3 mm (SD 1.1); P=NS | 1 study | Ungraded |
Coating material (bonding material or sealant) WITH fluoride release vs Coating material WITHOUT fluoride release Initiation of white spot lesions (WSL), visual-tactile assessment · Patients of any age (11-40 years) receiving comprehensive/fixed orthodontic treatment with fixed appliances · 1-24 months follow-up Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel… (2021) | RR 0.84 [0.70, 1.01] | 10 studies · 4705 participants | Very low |
Schwarz appliance vs No active treatment (control) Lower incisors to mandible (position, mm) at 9 months · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · 9 months Orthodontic treatment for crowded teeth in children (2021) · Cochrane | MD 0.39 [0.11, 0.67] | 1 study · 28 participants | Ungraded |
Bleaching before resin infiltration (bleaching + infiltration) vs Resin infiltration alone Masking effect (esthetic improvement) · Patients with dental fluorosis Efficacy of resin infiltration to mask post-orthodontic or non-post-orthodontic white spot lesions or… (2021) | MD -0.30 [-0.98, 0.39] | 2 studies | Moderate |
Copper nickel-titanium archwire vs Nickel-titanium archwire Time to alignment (days) · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · alignment Orthodontic treatment for crowded teeth in children (2021) · Cochrane | MD -2.63 [-14.50, 9.24] | 2 studies · 191 participants | Ungraded |
Active self-ligating brackets vs Passive self-ligating brackets Amount of crowding (upper anterior crowding) · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · baseline Orthodontic treatment for crowded teeth in children (2021) · Cochrane | Only baseline upper anterior crowding reported (Pandis 2010a, n=70); evidence of baseline imbalance between groups (P=0.04); no post-treatment between-group crowding estimate reported. | 1 study | Ungraded |
Double primary (canine and first molar) tooth extraction vs Single primary (canine) tooth extraction Time taken for the canine to erupt into the mouth · Young people aged 9 to 14 years diagnosed with one or both palatally displaced permanent maxillary canines (PDC) Interventions for promoting the eruption of palatally displaced permanent canine teeth, without the need for… (2021) · Cochrane | no estimate extracted | 0 studies | No studies |