Gap finder
Search review questions
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 |
|---|---|---|---|
Light vibrational forces (LVF) vs Conventional orthodontic appliance treatment (placebo or no adjunct) Patient perception of pain and discomfort (VAS 0 to 100 mm), immediately after ligation of initial archwire · Adolescents and adults with malocclusion undergoing orthodontic treatment with fixed or removable appliances · Immediately after ligation of initial archwire (also 4-8h, 1, 3, 7 days) Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | MD 2.56 [-2.35, 7.47] | 3 studies · 153 participants | Low |
CAD/CAM nitinol fixed (bonded) retainer vs Conventional/analogue multistrand fixed (bonded) retainer Survival of retainers (failure, lower arch) · People who had received fixed appliance orthodontic treatment · 12 months, lower arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | RR 1.29 [0.67, 2.49] | 1 study · 41 participants | Very low |
Chlorhexidine (CHX) mouthwash (adjunct to mechanical cleaning) vs Blank control (no mouthwash; before-after comparison) Plaque Index (PI, Silness & Loe 1964) · Orthodontic patients (any age) undergoing orthodontic treatment (mostly fixed appliances) · <=3 months (short-term) The efficacy of mouthwashes on oral microorganisms and gingivitis in patients undergoing orthodontic… (2023) | WMD -0.70 [-1.12, -0.27] | 4 studies · 188 participants | Very low |
Full-time clear plastic (removable) retainer vs Any type of fixed (bonded) retainer Survival of retainers (failure, lower arch) · People who had received fixed appliance orthodontic treatment · 12 months, lower arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | RR 3.42 [1.38, 8.47] | 1 study · 77 participants | Very low |
Low level laser therapy (LLLT) vs Conventional orthodontic appliance treatment Harms and side effects arising during treatment · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | SoF states harms/side effects Not reported; Ghaffer 2022 (the only LLLT study to assess harms) reported no serious harms other than gingivitis associated with plaque accumulation. | 1 study | Ungraded |
Cetylpyridinium chloride (CPC) mouthwash vs Blank control (no mouthwash; before-after comparison) Plaque-related index · Orthodontic patients (any age) undergoing orthodontic treatment (mostly fixed appliances) · <=3 months (short-term) The efficacy of mouthwashes on oral microorganisms and gingivitis in patients undergoing orthodontic… (2023) | BBPI was significantly reduced compared to blank control [47]. PI was significantly reduced compared to blank control [50]. The amount of dental plaque was significantly reduced compared to baseline [38]. | 3 studies | Very low |
Low level laser therapy (LLLT) vs Conventional orthodontic appliance treatment Periodontal health during molar intrusion · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | Abellan 2021 assessed periodontal health (plaque index, pocket depth, bleeding on probing) after intrusion of maxillary molars; no evidence of significant difference with LLLT. Statistical test results not published. | 1 study | Ungraded |
Fibre-reinforced composite fixed (bonded) retainer vs Multistrand / spiral wire fixed (bonded) retainer Survival of retainers (failure, lower arch) · People who had received fixed appliance orthodontic treatment · 12 months, lower arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | RR 1.01 [0.84, 1.21] | 7 studies · 1337 participants | Low |
Low level laser therapy (LLLT) vs Conventional orthodontic appliance treatment Total number of orthodontic appliance adjustment appointments during alignment stage · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment · Alignment stage Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | MD -2.25 [-2.52, -1.97] | 2 studies · 125 participants | Very low |
Herbal mouthwash vs Placebo Cariogenic bacteria (Mutans streptococci) · Orthodontic patients · ≤ 3 months The efficacy of mouthwashes on oral microorganisms and gingivitis in patients undergoing orthodontic… (2023) | Colony count of MS was significantly reduced compared to placebo [52]; colony count was slightly reduced compared to placebo in a short time in one study [40]. | 2 studies | Very low |
Part-time clear plastic (removable) retainer vs Any type of fixed (bonded) retainer Survival of retainers (failure, lower arch) · People who had received fixed appliance orthodontic treatment · 12 months, lower arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | RR 0.44 [0.20, 0.98] | 1 study · 57 participants | Very low |
Low level laser therapy (LLLT) vs Conventional orthodontic appliance treatment Patient perception of pain and discomfort (VAS 0 to 100 mm) · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment · Space closure / first visit Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | MD -0.4 [-1.87, 1.07] | 1 study · 37 participants | Very low |
Hawley removable retainer vs Clear plastic removable retainer Stability: Little's Irregularity Index (lower arch) · People who had received fixed appliance orthodontic treatment · 12 months, lower arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | MD 0.01 [-0.65, 0.67] | 1 study · 30 participants | Very low |
Low level laser therapy (LLLT) vs Conventional orthodontic appliance treatment Duration of orthodontic treatment during alignment stage · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment · Alignment stage Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | MD -48.87 [-56.48, -41.26] | 3 studies · 92 participants | Very low |
Upper clear plastic retainer + lower fixed canine-to-canine retainer vs Positioner Stability: Little's Irregularity Index (lower arch) · People who had received fixed appliance orthodontic treatment · 2 years, lower arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | MD -1.00 [-1.65, -0.35] | 1 study · 46 participants | Ungraded |
Full-time wear of removable retainer (any type) vs Part-time wear of removable retainer (any type) Survival of retainers · People who had received fixed appliance orthodontic treatment · 12 months, lower arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | Not measured | 0 studies | No studies |
Fluoride mouthwash (e.g., NaF / amine fluoride) vs Blank control (no mouthwash; before-after comparison) Gingival inflammation-related index · Orthodontic patients (any age) undergoing orthodontic treatment (mostly fixed appliances) · <=3 months (short-term) The efficacy of mouthwashes on oral microorganisms and gingivitis in patients undergoing orthodontic… (2023) | MGI' and BI' was significantly reduced compared to baseline [34]. BOP and GI was slightly lower compared to blank control [46]. | 2 studies | Very low |
Full-time wear of removable retainer (any type) vs Part-time wear of removable retainer (any type) Adverse effects on oral health · People who had received fixed appliance orthodontic treatment · 12 months, lower arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | Not measured | 0 studies | No studies |
Light vibrational forces (LVF) vs Conventional orthodontic appliance treatment (placebo or no adjunct) Harms and side effects: orthodontically-induced inflammatory root resorption (OIIRR), mm · Adolescents and adults with malocclusion undergoing orthodontic treatment with fixed or removable appliances Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | MD 0.09 [-0.35, 0.53] | 1 study · 50 participants | Low |
Fluoride mouthwash vs Blank control Plaque-related index · Orthodontic patients · ≥ 12 months The efficacy of mouthwashes on oral microorganisms and gingivitis in patients undergoing orthodontic… (2023) | PI was similar to blank control [37]; API was slightly reduced compared to blank control and significant at 6 and 9 months [59]. | 2 studies | Very low |
Fibre-reinforced composite fixed (bonded) retainer vs Multistrand / spiral wire fixed (bonded) retainer Adverse effects on oral health: bleeding on probing (lower arch) · People who had received fixed appliance orthodontic treatment · 12 months, lower arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | No RCTs at 12-month follow-up; 1 RCT at 6 months found no difference (very low-certainty) | 0 studies | No studies |
Hawley removable retainer vs Clear plastic removable retainer Survival of retainers (failure, upper and lower arches) · People who had received fixed appliance orthodontic treatment · 12 months, upper and lower arches Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | RR 0.60 [0.43, 0.83] | 1 study · 111 participants | Very low |
Hawley removable retainer vs Clear plastic removable retainer Patient satisfaction: comfort (VAS, upper and lower arches) · People who had received fixed appliance orthodontic treatment · 12 months, upper and lower arches Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | No RCTs at 12 months; 1 RCT at 6 months: Hawley less comfortable (VAS MD -1.86, 95% CI -2.19 to -1.53; very low-certainty) | 0 studies | No studies |
Clear aligners (CA) vs Conventional fixed orthodontic appliances (CF) Plaque accumulation (Plaque Index) · Orthodontic patients undergoing comprehensive treatment (late mixed or permanent dentition, no active caries) · Range 1 to 12 months (maximum time-point per study), Study design: non-randomized studies of interventions White spot lesions, plaque accumulation and salivary caries-associated bacteria in clear aligners compared… (2023) | SMD -1.46 [-2.77, -0.15] | 5 studies · 246 participants | Moderate |
Low level laser therapy (LLLT) vs Conventional orthodontic appliance treatment Patient-reported need for analgesics · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | Patient-reported need for analgesics | Not reported | NR | No studies |
Low level laser therapy (LLLT) vs Conventional orthodontic appliance treatment Total number of orthodontic appliance adjustment visits during overall treatment · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | No study reported on the influence of LLLT on the total number of orthodontic appliance adjustment visits to complete a course of treatment. | NR | No studies |
Fluoride mouthwash (e.g., NaF / amine fluoride) vs Blank control (no mouthwash; before-after comparison) Cariogenic bacteria (Lactobacilli colony count) · Orthodontic patients (any age) undergoing orthodontic treatment (mostly fixed appliances) · >=12 months (long-term) The efficacy of mouthwashes on oral microorganisms and gingivitis in patients undergoing orthodontic… (2023) | Colony count of LB was similar to blank control according to two studies [37, 59]. | 2 studies | Very low |
Upper fixed (bonded) retainer vs No retention Stability: Little's Irregularity Index (upper arch) · People who had received fixed appliance orthodontic treatment · 2 years, upper arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | MD -0.90 [-1.33, -0.47] | 1 study · 63 participants | Ungraded |
Fluoride varnish applied periodically (at least quarterly) around the bracket bases during treatment vs Placebo varnish, resin sealant, or standard care (oral hygiene instructions) Prevalence of white spot lesions (WSL) at debonding, subject level · Healthy adolescents and adults undergoing orthodontic treatment with fixed multi-bracket appliances · At debonding Prevention of white spot lesions with fluoride varnish during orthodontic treatment with fixed appliances: a… (2023) | RR 0.64 [0.42, 0.98] | 5 studies · 558 participants | Very low |
Low level laser therapy (LLLT) vs Conventional orthodontic appliance treatment Duration of total overall orthodontic treatment · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | No study reported on the influence of LLLT on the total overall orthodontic treatment duration. | NR | No studies |
Clear aligners (CA) vs Conventional fixed orthodontic appliances (CF) Severity of white spot lesions (surface area and depth) · Orthodontic patients undergoing comprehensive treatment (late mixed or permanent dentition, no active caries) · Baseline to end of treatment (varying) White spot lesions, plaque accumulation and salivary caries-associated bacteria in clear aligners compared… (2023) | Not meta-analyzed. 2 RCTs assessed WSL severity by lesion surface area (Albhaisi 2020 [12]; Alshatti 2017 [31]) and 1 (Albhaisi 2020 [12]) also by lesion depth; reported narratively with differing methods, generally… | 2 studies | Ungraded |
Light-emitting diode (LED) photobiomodulation vs Conventional orthodontic appliance treatment Orthodontic tooth movement (OTM) during alignment stage · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | Orthodontic tooth movement (OTM) during alignment stage | Not reported | NR | No studies |
Chlorhexidine (CHX) mouthwash (adjunct to mechanical cleaning) vs Blank control (no mouthwash; before-after comparison) Gingival Index (GI, Loe & Silness 1963) · Orthodontic patients (any age) undergoing orthodontic treatment (mostly fixed appliances) · <=3 months (short-term) The efficacy of mouthwashes on oral microorganisms and gingivitis in patients undergoing orthodontic… (2023) | WMD -0.54 [-0.96, -0.13] | 6 studies · 274 participants | Very low |
Light vibrational forces (LVF) vs Conventional orthodontic appliance treatment (placebo or no adjunct) Harms: serious adverse effects · Adolescents and adults with malocclusion undergoing orthodontic treatment with fixed or removable appliances Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | No serious adverse effects were reported across five studies that assessed harms (Katchooi 2018; Lombardo 2018; Pavlin 2015; Reiss 2020; Taha 2020). | 5 studies | Ungraded |
Light vibrational forces (LVF) vs Conventional orthodontic appliance treatment (placebo or no adjunct) Rate of orthodontic tooth movement (OTM) during space closure stage (en masse, mm/month) · Adolescents and adults with malocclusion undergoing orthodontic treatment with fixed or removable appliances · Space closure stage Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | MD 0.10 [-0.08, 0.29] | 2 studies · 81 participants | Low |
Light-emitting diode (LED) photobiomodulation vs Conventional orthodontic appliance treatment Patient-reported need for analgesics · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | Patient-reported need for analgesics | Not reported | NR | No studies |
Light vibrational forces (LVF) vs Conventional orthodontic appliance treatment (placebo or no adjunct) Improvement in occlusion / orthodontic treatment occlusal outcome (Peer Assessment Rating, PAR) · Adolescents and adults with malocclusion undergoing orthodontic treatment with fixed or removable appliances Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | Woodhouse 2015 (81 participants, 22 dropouts): PAR reduction intervention median 28.0 (IQR 21.0-38.0), control median 29.0 (IQR 24.0-31.0), placebo median 27.0 (IQR 20.0-35.0); percentage improvement medians 88.9 /… | 1 study · 59 participants | Ungraded |
Light vibrational forces (LVF) vs Conventional orthodontic appliance treatment (placebo or no adjunct) Patient-reported need for analgesics during first week of initial aligning archwire · Adolescents and adults with malocclusion undergoing orthodontic treatment with fixed or removable appliances · First week of initial aligning archwire Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | OR 1.64 [0.60, 4.53] | 2 studies · 76 participants | Low |
CAD/CAM nitinol fixed (bonded) retainer vs Conventional/analogue multistrand fixed (bonded) retainer Adverse effects on oral health: Gingival Index (lower arch) · People who had received fixed appliance orthodontic treatment · 12 months, lower arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | MD 0.00 [-0.16, 0.16] | 2 studies · 107 participants | Low |
Low level laser therapy (LLLT) vs Conventional orthodontic appliance treatment Rate of orthodontic tooth movement during alignment stage (percentage reduction in LII), first month · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment · First month of alignment (also second month) Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | MD 1.63 [-2.60, 5.86] | 2 studies · 56 participants | Very low |
Herbal mouthwash vs Placebo Gingival inflammation-related index · Orthodontic patients · ≤ 3 months The efficacy of mouthwashes on oral microorganisms and gingivitis in patients undergoing orthodontic… (2023) | GBI was significantly reduced compared to placebo [41]; GBI was significantly reduced compared to placebo [56]; BI was significantly reduced compared to placebo [40]. | 3 studies | Very low |
Low level laser therapy (LLLT) vs Conventional orthodontic appliance treatment Rate of maxillary molar intrusion for correction of anterior open bite · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment · 3 and 6 months Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | Two studies (62 participants), not pooled. Abellan 2021: no significant difference in molar intrusion at 3 months (1.25 vs 1.72 mm) or 6 months (1.09 vs 1.28 mm), nor rate per month. Hasan 2022: increased intrusion… | 2 studies · 62 participants | Ungraded |
Light vibrational forces (LVF) vs Conventional orthodontic appliance treatment (placebo or no adjunct) Oral health-related quality of life (OHRQoL) · Adolescents and adults with malocclusion undergoing orthodontic treatment with fixed or removable appliances Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | Katchooi 2018 (unclear risk of bias): light vibrational forces had no statistically significant (P>0.05) effect on OHRQoL when used with orthodontic aligners. | 1 study · 27 participants | Ungraded |
Upper clear plastic retainer + lower interproximal reduction (adjunctive) vs Positioner Stability: Little's Irregularity Index (lower arch) · People who had received fixed appliance orthodontic treatment · 2 years, lower arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | MD -0.70 [-1.37, -0.03] | 1 study · 45 participants | Ungraded |
Herbal / plant-extract mouthwash (e.g., essential oils, Persica, propolis, Azadirachta indica, chamomile, Aloe vera) vs Blank control (no mouthwash; before-after comparison) Gingival Index (GI, Loe & Silness 1963) · Orthodontic patients (any age) undergoing orthodontic treatment (mostly fixed appliances) · <=3 months (short-term) The efficacy of mouthwashes on oral microorganisms and gingivitis in patients undergoing orthodontic… (2023) | WMD -0.20 [-0.32, -0.09] | 3 studies · 132 participants | Moderate |
Chlorhexidine mouthwash vs Placebo Plaque Index · Orthodontic patients · ≤ 3 months The efficacy of mouthwashes on oral microorganisms and gingivitis in patients undergoing orthodontic… (2023) | Plaque Index was significantly reduced compared to placebos according to two studies [20; 32]. | 2 studies | Very low |
CAD/CAM nitinol fixed (bonded) retainer vs Conventional/analogue multistrand fixed (bonded) retainer Adverse effects on oral health: bleeding on probing (lower arch) · People who had received fixed appliance orthodontic treatment · 12 months, lower arch Retention procedures for stabilising tooth position after treatment with orthodontic braces (2023) · Cochrane | No RCTs at 12-month follow-up; 2 RCTs at 6 months found no difference (low-certainty) | 0 studies | No studies |
Light-emitting diode (LED) photobiomodulation vs Conventional orthodontic appliance treatment Total number of orthodontic appliance adjustment appointments during treatment · Adolescents and adults with malocclusion undergoing fixed orthodontic appliance treatment Non‐surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic… (2023) · Cochrane | Total number of orthodontic appliance adjustment appointments required during treatment stage | Not reported | NR | No studies |
Fluoride mouthwash vs Blank control Cariogenic bacteria (Mutans streptococci) · Orthodontic patients · ≥ 12 months The efficacy of mouthwashes on oral microorganisms and gingivitis in patients undergoing orthodontic… (2023) | Colony count of MS was similar to blank control according to two studies [37; 59]. | 2 studies | Very low |
Clear aligners (CA) vs Conventional fixed orthodontic appliances (CF) Salivary caries-associated bacteria (S. mutans and Lactobacilli, subjects with >10^5 CFU/mL) · Orthodontic patients undergoing comprehensive treatment (late mixed or permanent dentition, no active caries) · 3 and 6 months White spot lesions, plaque accumulation and salivary caries-associated bacteria in clear aligners compared… (2023) | Not meta-analyzed (insufficient number of studies). Both included observational studies (Mummolo 2020 [19]; Mummolo 2020 [25]) reported a higher number of subjects with S. mutans and Lactobacilli >10^5 CFU/mL in the… | 2 studies | Ungraded |