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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 |
|---|---|---|---|
Double primary (canine and first molar) tooth extraction vs Single primary (canine) tooth extraction 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) · 18 months Interventions for promoting the eruption of palatally displaced permanent canine teeth, without the need for… (2021) · Cochrane | RR 1.64 [0.33, 8.03] | 1 study · 23 participants | Ungraded |
Removable tooth-borne expansion (expansion plate) vs Observation (no treatment) Canine expansion (inter-canine 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 2.59 [2.18, 3.01] | 3 studies · 145 participants | Moderate |
Fixed tooth-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 Orthodontic treatment for posterior crossbites (2021) · Cochrane | MD 0.66 [-0.04, 1.36] | 2 studies · 65 participants | Low |
Lower lingual arch vs No active treatment (control) Lower molars 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 -1.11 [-1.51, -0.71] | 1 study · 30 participants | Ungraded |
Fixed tooth-borne expansion (quad-helix) vs Removable tooth-borne expansion (expansion plate) Crossbite correction · 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 | RR 1.29 [1.13, 1.46] | 3 studies · 151 participants | Moderate |
Double primary (canine and first molar) tooth extraction vs Single primary (canine) tooth extraction 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 |
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, Modified enamel decalcification index (Cronan 2012) Efficacy of resin infiltration to mask post-orthodontic or non-post-orthodontic white spot lesions or… (2021) | SMD 0.98 [0.83, 1.13] | 1 study · 768 participants | Ungraded |
Multistranded stainless steel archwire vs Stainless steel archwire Amount of crowding (change in mandibular crowding) at 8 weeks · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · 8 weeks Orthodontic treatment for crowded teeth in children (2021) · Cochrane | MD -18.40 [-47.12, 10.32] | 1 study · 23 participants | Very low |
Clear aligners (Invisalign / thermoformed aligners) vs Fixed appliances S. mutans counts (5th-root transformed) · 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 -2.22 [-6.82, 2.38] | 1 study | Ungraded |
Extraction of the primary (baby) canine (single primary tooth extraction) vs No extraction (non-intervention control) Number of participants referred for surgical exposure of the PDC · 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 0.61 [0.29, 1.28] | 1 study · 45 participants | Very low |
Cervical pull headgear vs Minor interceptive procedures (control) Lower incisors to mandible at 2 years · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · 2 years Orthodontic treatment for crowded teeth in children (2021) · Cochrane | MD 1.4 [-0.42, 3.22] | 1 study · 64 participants | Ungraded |
Expansion plate with conventional expansion screw vs Expansion plate with spring-loaded expansion screw Molar and 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 | Oshagh 2012: no significant differences in discomfort and arch size changes; results inadequately reported (no usable data) | 1 study | Ungraded |
Fluoride-releasing resin-based bonding agent vs Non-fluoride resin-based bonding agent 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 bonding agents Efficacy of sealants and bonding materials during fixed orthodontic treatment to prevent enamel… (2021) | RR 0.97 [0.79, 1.19] | 5 studies · 3517 participants | Ungraded |
Bone-borne expansion vs Fixed tooth-borne expansion (Hyrax) Canine expansion (inter-canine distance) · 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 | Not measured (SoF 7) | 0 studies | No studies |
Self-ligating brackets vs Conventional brackets Harms (discomfort, periodontal/gingival health, root resorption) · Children or adolescents (aged 16 years old or under) receiving orthodontic treatment to prevent or correct crowded teeth · up to 9 months Orthodontic treatment for crowded teeth in children (2021) · Cochrane | No evidence of differences between self-ligating and conventional brackets for discomfort (Atik 2014, Miles 2010), plaque/gingival index and probing depth (Atik 2014), or maxillary incisor root resorption (Aras 2018).… | 3 studies | Ungraded |
Fixed tooth-bone-borne expansion vs Fixed tooth-borne expansion (Hyrax) Canine expansion (inter-canine distance) · 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 | Not measured (SoF 6) | 0 studies | No studies |
Bleaching gel with added remineralising agent (fluoride, calcium, or CPP-ACP) vs Bleaching alone (no remineralising agent) Whitening (bleaching) efficacy · Demineralised / white-spot-lesion enamel (in vitro specimens) Is Bleaching Effective in Managing Post-orthodontic White-spot Lesions? A Systematic Review. (2020) | Low-quality in vitro data indicated that the presence of fluoride or any other remineralising agent did not impair the whitening effect. | 3 studies | Ungraded |
Tooth bleaching (carbamide or hydrogen peroxide; home and/or in-office) vs No bleaching (untreated control) Colour change / camouflage of white spot lesions (reduction of colour disparity between carious and sound enamel) · Permanent teeth with post-orthodontic white spot lesions (orthodontic patients and in vitro enamel specimens) Is Bleaching Effective in Managing Post-orthodontic White-spot Lesions? A Systematic Review. (2020) | The results showed that bleaching of WSL can diminish colour disparities between carious and non-affected areas, but the certainty of the evidence was very low. | 3 studies | Ungraded |
Laser/light-activated bleaching vs Conventional (non-laser) bleaching with hydrogen or carbamide peroxide Enamel microhardness / caries susceptibility · Permanent teeth enamel (in vitro specimens) Is Bleaching Effective in Managing Post-orthodontic White-spot Lesions? A Systematic Review. (2020) | In two studies having high risk of bias, laser-activated bleaching did not seem to affect enamel microhardness or caries risk when compared to conventional bleaching with hydrogen or carbamide peroxide. | 2 studies | Ungraded |
Tooth bleaching (carbamide or hydrogen peroxide; home or in-office) vs No bleaching (untreated or pH-cycling control) Enamel demineralisation and susceptibility to caries or acid erosion (microhardness, mineral loss) · Permanent teeth / enamel specimens (in vitro) Is Bleaching Effective in Managing Post-orthodontic White-spot Lesions? A Systematic Review. (2020) | Four studies at high risk of bias and one study at moderate risk reached the overall conclusion that neither home- nor in-office bleaching of permanent teeth was associated with an increased susceptibility to… | 5 studies | Ungraded |
Home or in-office bleaching vs No bleaching Caries susceptibility, enamel demineralisation, erosion, or microhardness · Permanent teeth or extracted human teeth with artificial lesions · Varied or not stated Is Bleaching Effective in Managing Post-orthodontic White-spot Lesions? A Systematic Review. (2020) | no estimate extracted | 5 studies | Ungraded |
Tooth bleaching (combined in-office and home bleaching) vs No bleaching (untreated control) Patient satisfaction with aesthetic outcome · Orthodontic patients with post-orthodontic white spot lesions (permanent teeth) · 28 days Is Bleaching Effective in Managing Post-orthodontic White-spot Lesions? A Systematic Review. (2020) | All patients in the bleaching group were satisfied with the outcome; the patients were pleased with the aesthetic outcome of bleaching (Knösel 2007). | 1 study · 10 participants | Ungraded |
Bleaching vs No bleaching or alternative control Colour disparity between carious and non-affected enamel · Permanent teeth with post-orthodontic or artificial white spot lesions · Varied; 28 days in the RCT Is Bleaching Effective in Managing Post-orthodontic White-spot Lesions? A Systematic Review. (2020) | no estimate extracted | 3 studies | Ungraded |
Bleaching plus fluoride, calcium, or CPP-ACP vs Bleaching without a remineralising additive Mineral loss, lesion depth, or enamel microhardness · Extracted human teeth with artificial white spot lesions · Varied or not stated Is Bleaching Effective in Managing Post-orthodontic White-spot Lesions? A Systematic Review. (2020) | no estimate extracted | 4 studies | Ungraded |
Bleaching gel with added remineralising agent (fluoride, calcium, or CPP-ACP) vs Bleaching alone (no remineralising agent) Enamel mineral loss / remineralisation · Demineralised / white-spot-lesion enamel (in vitro specimens) Is Bleaching Effective in Managing Post-orthodontic White-spot Lesions? A Systematic Review. (2020) | Inconclusive: F/Ca/CPP-ACP additives reduced mineral loss on SOUND enamel (refs 8,10,16) but not verified for artificial caries lesions (ref 35) | 4 studies | Ungraded |
Fixation and stabilisation (splint type/duration) vs Different splint, no splint, or different splinting duration Outcome NR · People with avulsed and replanted permanent (front) teeth Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted (2019) · Cochrane | no estimate extracted | 0 studies | No studies |
12,500 ppm F (NaF/olaflur/dectaflur) amine fluoride gel vs 0 ppm F placebo gel Number of participants with more severe DLs (severity of DLs) · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond (end of orthodontic treatment) Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | Additional SoF Table 1. Number of participants with more severe DLs: none of the trials reported this outcome. | 0 studies | No studies |
Hyperbaric oxygen (following replantation) vs Control Tooth survival at 12 months · People with avulsed and replanted permanent (front) teeth · 12 months Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted (2019) · Cochrane | RR 1.21 [1.07, 1.36] | 1 study · 69 participants | Very low |
Patient-used 5000 ppm F toothpaste, daily vs 1450 ppm F (conventional) toothpaste, daily Number of participants with more severe DLs (severity of DLs) · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond (end of orthodontic treatment) Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | SoF 3. Number of participants with more severe DLs: none of the trials reported this outcome. | 0 studies | No studies |
1400/250 ppm F (amine F/SnF2) toothpaste + mouthrinse, daily vs 1400/250 ppm F (NaF) toothpaste + mouthrinse, daily Number of participants with more severe DLs (severity of DLs) · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond (end of orthodontic treatment) Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | Additional SoF Table 2. Number of participants with more severe DLs: none of the trials reported this outcome. | 0 studies | No studies |
1400/250 ppm F (amine F/SnF2) toothpaste + mouthrinse, daily vs 1400/250 ppm F (NaF) toothpaste + mouthrinse, daily Adverse effects · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond (end of orthodontic treatment) Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | Additional SoF Table 2. Adverse effects: none of the trials reported this outcome. | 0 studies | No studies |
Ledermix root canal medicament (day 0 to 10) vs Ultracal root canal medicament (day 7 to 10) Adverse effects · People with avulsed and replanted permanent (front) teeth Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted (2019) · Cochrane | Day 2012 used a formal methodology to identify and report adverse effects, with none identified. | 1 study · 22 participants | Ungraded |
Thymosin alpha 1 (10-minute soak prior to replantation) vs Control (saline) Tooth survival at 12 months · People with avulsed and replanted permanent (front) teeth · 12 months Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted (2019) · Cochrane | RR 1.46 [1.11, 1.91] | 1 study · 73 participants | Very low |
Intraoral fluoride-releasing glass bead device attached to the brace vs 250 ppm F (daily) fluoride mouthrinse Number of participants with more severe DLs (severity of DLs) · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond (end of orthodontic treatment) Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | Additional SoF Table 3. Number of participants with more severe DLs: none of the trials reported this outcome. | 0 studies | No studies |
1400/250 ppm F (amine F/SnF2) toothpaste + mouthrinse, daily vs 1400/250 ppm F (NaF) toothpaste + mouthrinse, daily Gingival bleeding index (mean change from baseline) · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond; follow-up 1.5 years Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | MD -0.07 [-0.15, 0.01] | 1 study · 97 participants | Very low |
Extra-oral pulp extirpation at day 0 vs Intra-oral pulp extirpation at day 7 Adverse effects · People with avulsed and replanted permanent (front) teeth Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted (2019) · Cochrane | Giannetti 2006 did not report this outcome; following email correspondence, authors reported no adverse effects were seen (uncertain whether formally assessed). | 1 study | Ungraded |
Ledermix root canal medicament (day 0 to 10) vs Ultracal root canal medicament (day 7 to 10) Aesthetics (discolouration) at 12 months (patient level) · People with avulsed and replanted permanent (front) teeth · 12 months Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted (2019) · Cochrane | RR 7.20 [1.03, 50.28] | 1 study · 22 participants | Very low |
1400/250 ppm F (amine F/SnF2) toothpaste + mouthrinse, daily vs 1400/250 ppm F (NaF) toothpaste + mouthrinse, daily White spot lesion index (mean change from baseline) · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond; follow-up 1.5 years Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | MD -0.05 [-0.10, 0] | 1 study · 97 participants | Very low |
Treatment with antibiotics vs No antibiotics, placebo, or different types of antibiotics Outcome NR · People with avulsed and replanted permanent (front) teeth Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted (2019) · Cochrane | no estimate extracted | 0 studies | No studies |
Thymosin alpha 1 (10-minute soak prior to replantation) vs Control (saline) Pain · People with avulsed and replanted permanent (front) teeth · day 1 Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted (2019) · Cochrane | A benefit in pain scores was reported on day 1 in favour of the thymosin alpha 1 group; no difference found on days 2 and 5. | 1 study · 73 participants | Ungraded |
Professionally-applied fluoride varnish (7700 or 10,000 ppm F), every 6 weeks vs Non-fluoride (placebo) varnish Number of participants with new demineralised lesions (DLs) · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond; follow-up 1.7 years Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | RR 0.52 [0.14, 1.93] | 2 studies · 405 participants | Low |
Patient-used 250 ppm F mouthrinse (100 ppm amine F/150 ppm NaF), daily vs 0 ppm F placebo mouthrinse, daily Adverse effects · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond (end of orthodontic treatment) Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | SoF 4. Adverse effects: none of the trials reported this outcome. | 0 studies | No studies |
Professionally-applied fluoride varnish (7700 ppm F ammonium fluoride), every 6 weeks vs Non-fluoride (placebo) varnish Number of participants with more severe DLs (score 3 or 4 versus 1 or 2) · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond; follow-up 1.7 years Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | RR 0.46 [0.22, 0.95] | 1 study · 148 participants | Low |
Resin-modified glass ionomer cement for bonding orthodontic brackets vs Light-cured composite resin for bonding brackets Number of participants with new demineralised lesions (DLs) · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond; follow-up 17.6 months Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | RR 1.17 [0.69, 1.99] | 1 study · 173 participants | Low |
Hyperbaric oxygen (following replantation) vs Control Adverse effects · People with avulsed and replanted permanent (front) teeth Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted (2019) · Cochrane | Chen 2000 did not report this outcome; following email correspondence, authors reported no adverse effects were seen (uncertain whether formally assessed). | 1 study | Ungraded |
Intraoral fluoride-releasing glass bead device attached to the brace vs 250 ppm F (daily) fluoride mouthrinse Adverse effects · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond; follow-up 19 months Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | Additional SoF Table 3. Adverse effects: current design of the fluoride glass bead inadequate; high attrition partly due to bead breakages ('an improved method of attachment is needed'). 37 participants (1 RCT, Luther… | 1 study · 37 participants | Very low |
Thymosin alpha 1 (10-minute soak prior to replantation) vs Control (saline) Adverse effects · People with avulsed and replanted permanent (front) teeth Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted (2019) · Cochrane | Loo 2008 did not report this outcome; following email correspondence, authors reported no adverse effects were seen (uncertain whether formally assessed). | 1 study | Ungraded |
Resin-modified glass ionomer cement for bonding orthodontic brackets vs Light-cured composite resin for bonding brackets Adverse effects · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond; follow-up 17.6 months Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | SoF 5. Adverse effects: no evidence that either intervention had adverse effects. 173 participants (1 RCT, Benson 2019); certainty LOW. | 1 study · 173 participants | Low |
Resin-modified glass ionomer cement for bonding orthodontic brackets vs Light-cured composite resin for bonding brackets Number of participants with more severe DLs of aesthetic concern · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond; follow-up 17.6 months Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | RR 1.18 [0.45, 3.12] | 1 study · 173 participants | Low |
12,500 ppm F (NaF/olaflur/dectaflur) amine fluoride gel, professionally applied every 3 months plus home use vs 0 ppm F placebo gel Number of participants with new demineralised lesions (DLs) · Orthodontic patients of any age with fixed braces (new DLs assessed at debond) · At debond; mean follow-up 16.6 months Fluorides for preventing early tooth decay (demineralised lesions) during fixed brace treatment (2019) · Cochrane | RR 0.99 [0.76, 1.27] | 1 study · 312 participants | Very low |