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.

Limit to evidence status or GRADE (optional)

75,239 questions in 5,342 reviews

current versions
No studies 15,213 · 20.2%Ungraded 10,323 · 13.7%Very low 17,528 · 23.3%Low 17,951 · 23.9%Moderate 11,190 · 14.9%High 3,034 · 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.

QuestionEffectEvidenceStatus / GRADE
Oral cancer patients (cases) vs Healthy controls
Periodontal parameters (all measures pooled) in OC cases vs controls · Adults in case-control studies (oral cancer patients vs healthy controls) · Not specified, Overall (all periodontal measures pooled)
Periodontitis and the risk of oral cancer: a meta-analysis of case-control studies. (2024)
SMD 0.95 [0.41, 1.49]5 studiesUngraded
Non-syndromic cleft lip and palate (CLP) status and its oral microbiota (exposure/grouping) vs Children and adolescents aged 0-18 years without CLP (controls)
Streptococcus mutans salivary/plaque counts (cariogenic microbiota) · Children and adolescents aged 0-18 years with non-syndromic cleft lip and palate (CLP)
Characterization of the oral microbiota and the relationship of the oral microbiota with the dental and… (2024)
Two studies were analyzed that reported the outcome in means of the presence of Streptococcus mutans, and that there was no difference between the means for healthy patients and those with CLP. The results of these…2 studiesUngraded
Surgically-anchored orthodontic treatment (miniplates) vs Untreated control (no treatment)
Overjet · Children and adolescents (aged 16 years or younger) with prominent lower front teeth (Class III malocclusion) · End of treatment
Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children (2024) · Cochrane
MD 7.69 [6.99, 8.40]1 study · 30 participantsLow
Consumption of xylitol chewing gum by women (mothers) vs Consumption of CHX/xylitol gum by women, or CHX varnish applied to women's dentition
Child microbiological presence (any mutans streptococci colonisation) · For interventions, pregnant women and mothers of infants in the first year of life; for outcomes, children up to 6…
Interventions with pregnant women, new mothers and other primary caregivers for preventing early childhood… (2024) · Cochrane
RR 0.60 [0.45, 0.81]2 studiesUngraded
Facemask vs Untreated control (no treatment)
Overjet · Children and adolescents (aged 16 years or younger) with prominent lower front teeth (Class III malocclusion) · End of treatment (9 to 15 months)
Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children (2024) · Cochrane
MD 5.04 [4.29, 5.80]2 studies · 92 participantsUngraded
Silver diamine fluoride (topical application) vs Control (placebo/no treatment or other topical fluoride agents)
Prevention of new caries (caries development/increment) · Preschool children (primary dentition) at risk of new caries · 6 to 18 months
The role of silver diamine fluoride as dental caries preventive and arresting agent: a systematic review and… (2024)
Narrative (2 RCTs; not meta-analyzed): Zheng 2023 reported mean decayed surfaces (ds) reduced from 0.7+/-1.9 to 0.4+/-1.5; Sirivichayakul 2023 reported a caries development rate of 27.2%.2 studiesUngraded
Adjunctive antimicrobial photodynamic therapy (aPDT) applied after subgingival instrumentation (SI) vs Subgingival instrumentation (SI) alone (hand or power-driven, or both), or SI plus placebo/sham aPDT
Change in clinical attachment level (CAL) · Adults (> 18 years) with a clinical diagnosis of periodontitis, receiving active (non-surgical anti-infective) treatment · 3 months (change from baseline)
Adjunctive antimicrobial photodynamic therapy for treating periodontal and peri‐implant diseases (2024) · Cochrane
MD 0.36 [0.24, 0.48]34 studies · 875 participantsUngraded
Occlusal splint vs Another occlusal splint with a different mechanism of action
Recurrence rate · People with temporomandibular disorders (TMD)
Occlusal interventions for managing temporomandibular disorders (2024) · Cochrane
Listed in Summary of findings 2 as 'Not reported'; this outcome was not reported by any included study for this comparison.0 studiesNo studies
Package of oral health education/promotion including oral hygiene advice for pregnant women, mothers, infants and young children, plus dietary and feeding practice advice for infants and young children vs Standard care
Child oral health behaviours · For interventions, pregnant women, mothers or other caregivers of infants in the first year of life; for outcomes,…
Interventions with pregnant women, new mothers and other primary caregivers for preventing early childhood… (2024) · Cochrane
Three trials (Muhoozi 2017; Pereira 2021; Yu 2021) reported changes in child oral health behaviours (other data): some benefit in favour of the intervention.3 studiesUngraded
Not applicable (single-group prevalence) vs Not applicable (single-group prevalence)
Early childhood caries (ECC) prevalence (%, dmft>0) · Children younger than 71 months (under 6 years) · Region: Europe
A systematic review and meta-analysis on early-childhood-caries global data. (2024)
Prevalence 36 [25, 47]13 studiesUngraded
Fluoride varnish applied before 4 years of age (biannual) vs Placebo varnish
Fluorosis (percentage prevalence in permanent teeth) · Children exposed to topical fluoride when under 6 years old; fluorosis assessed in permanent teeth at 6 to 18 years · Fluorosis assessed when most permanent teeth of interest had erupted (6 to 18 years)
Topical fluoride as a cause of dental fluorosis in children (2024) · Cochrane
RR 0.77 [0.45, 1.31]1 study · 123 participantsLow
TT+TC genotypes vs CC genotype
Dental caries · Children (<18 years) with vs without dental caries · Dominant model (TT+TC vs CC), Primary dentition
Association of vitamin D receptor gene polymorphisms with caries risk in children: a systematic review and… (2024)
OR 1.25 [0.08, 20.04]NRUngraded
Occlusal splint vs Physical therapy (ultrasound, exercise, sensorimotor training, laser, TENS, manual therapy)
Self-reported joint pain when chewing · People with temporomandibular disorders (TMD)
Occlusal interventions for managing temporomandibular disorders (2024) · Cochrane
Listed in Summary of findings 3 as 'Not reported'; this outcome was not reported by any included study for this comparison.0 studiesNo studies
Facemask with rapid maxillary expansion (RME) vs Facemask only
Wits appraisal · Children and adolescents (aged 16 years or younger) with prominent lower front teeth (Class III malocclusion) · End of treatment
Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children (2024) · Cochrane
MD 0.10 [-1.08, 1.29]2 studies · 60 participantsUngraded
Antioxidants (lycopene, curcumin, Oxitard) vs Placebo or no active treatment
Participant-reported resumption of normal eating, chewing and speech · People of any age with a confirmed diagnosis, by clinical examination and biopsy, of oral submucous fibrosis (OSF)
Interventions for managing oral submucous fibrosis (2024) · Cochrane
SoF: participant-reported resumption of normal eating, chewing and speech - outcome not reported by included studies.0 studiesNo studies
Pulpotomy (full or partial) vs None (single-arm success proportion)
Overall success (composite of clinical and radiographic success) · Permanent teeth with carious pulp exposure · >=12 months, Hemostasis unknown
Efficacy of pulpotomy for permanent teeth with carious pulp exposure: A systematic review and meta-analysis… (2024)
Proportion 0.802NRUngraded
Single-strand superelastic NiTi arch wire vs Coaxial superelastic NiTi arch wire
Alignment rate · People receiving orthodontic treatment with fixed appliances (upper and/or lower full arch) · 4 weeks
Initial arch wires used in orthodontic treatment with fixed appliances (2024) · Cochrane
MD -2.64 [-4.61, -0.67]2 studies · 64 participantsModerate
Mandibular third molar present vs Mandibular third molar absent
Spontaneous space closure · Children and adolescents after extraction of a mandibular permanent first molar (before eruption of the second molar) · Until eruption of the permanent second molar (median follow-up 4.0 years), Mandible
Spontaneous space closure after extraction of permanent first molars in children and adolescents: a… (2024)
OR 2.28 [1.67, 3.09]4 studies · 467 participantsLow
Postoperative systemic antibiotics (phenoxymethylpenicillin/penicillin VK, 7-day course), partial or total chemo-mechanical debridement and analgesics vs Matched placebo, partial or total chemo-mechanical debridement and analgesics
Pain at 24 hours · Adults with a symptomatic necrotic tooth or localised acute apical abscess (no signs of spreading infection or… · 24 hours
Systemic antibiotics for symptomatic apical periodontitis and acute apical abscess in adults (2024) · Cochrane
MD -0.03 [-0.53, 0.47]2 studies · 61 participantsVery low
TT genotype vs TG+GG genotypes
Dental caries · Children (<18 years) with vs without dental caries · Recessive model (TT vs TG+GG)
Association of vitamin D receptor gene polymorphisms with caries risk in children: a systematic review and… (2024)
OR 0.93 [0.68, 1.29]3 studies · 796 participantsUngraded
TT+TC genotypes vs CC genotype
Dental caries · Children (<18 years) with vs without dental caries · Dominant model (TT+TC vs CC), PCR-RFLP genotyping
Association of vitamin D receptor gene polymorphisms with caries risk in children: a systematic review and… (2024)
OR 0.70 [0.47, 1.05]NRUngraded
Extraction of the permanent first molar vs None (single-group prevalence)
Spontaneous space closure · Children and adolescents (<18 years) after extraction of a permanent first molar before eruption of the permanent… · Until eruption of the permanent second molar (median follow-up 4.0 years), Maxilla
Spontaneous space closure after extraction of permanent first molars in children and adolescents: a… (2024)
Prevalence 85.3 [73.7, 92.3]9 studies · 665 participantsUngraded
Silver diamine fluoride (SDF) vs Restoration (restorative treatment)
Adverse effects · Children and adults (with or without carious lesions) · 12 months, Children
Topical silver diamine fluoride (SDF) for preventing and managing dental caries in children and adults (2024) · Cochrane
Cleary 2022 reported that there were no unanticipated adverse events; adverse events were not defined.1 studyVery low
Milk-based probiotic vs No treatment or placebo (control)
Bacterial plaque index · Children and/or adolescents (<18 years) without background systemic disease · Probiotic presentation: milk (vs other presentations; p-interaction=0.01)
Efficacy of Probiotic Consumption on Oral Outcomes in Children and/or Adolescents: A Meta-Analysis. (2024)
MD -0.10 [-0.20, 0]NRUngraded
Silver diamine fluoride (SDF) vs Sealants or resin infiltration
Adverse effects · Children and adults (with or without carious lesions) · 24 months, Children
Topical silver diamine fluoride (SDF) for preventing and managing dental caries in children and adults (2024) · Cochrane
In 1 study, people complained about a transient bitter taste associated with SDF (with no associated data), with no other adverse effects. In another study, there were no adverse effects. No studies reported this…2 studies · 336 participantsVery low
Antioxidants (lycopene, curcumin, Oxitard) vs Placebo or no active treatment
Adverse effects · People of any age with a confirmed diagnosis, by clinical examination and biopsy, of oral submucous fibrosis (OSF)
Interventions for managing oral submucous fibrosis (2024) · Cochrane
Adverse effects (any): 0 in placebo vs 2 minor (flatulence and bloating); 90 (1); no GRADE rating given.1 study · 90 participantsUngraded
Not applicable (single-group prevalence) vs Not applicable (single-group prevalence)
Dental caries, prevalence · Primary school children in Ethiopia · Sampling technique: multi-stage random sampling
Prevalence of dental caries and associated factors among primary school children in Ethiopia: systematic… (2024)
Prevalence 21 [19, 23]1 study · 1736 participantsUngraded
Facemask with rapid maxillary expansion (RME) vs Reverse chin cup
ANB · Children and adolescents (aged 16 years or younger) with prominent lower front teeth (Class III malocclusion) · End of treatment
Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children (2024) · Cochrane
MD 0.20 [-0.71, 1.11]1 study · 42 participantsUngraded
G allele vs A allele
Dental caries · Children (<18 years) with vs without dental caries · Allelic model (G vs A)
Association of vitamin D receptor gene polymorphisms with caries risk in children: a systematic review and… (2024)
OR 1.56 [0.76, 3.24]4 studies · 1741 participantsUngraded
Vasodilators (isoxsuprine, xanthinol nicotinate) vs Placebo or no active treatment
Maximal mouth opening (interincisal distance) · People of any age with a confirmed diagnosis, by clinical examination and biopsy, of oral submucous fibrosis (OSF) · 3 to 6 months
Interventions for managing oral submucous fibrosis (2024) · Cochrane
MD 4.04 [-1.93, 10.02]2 studies · 85 participantsVery low
Occlusal splint vs Acupuncture
Recurrence rate · People with temporomandibular disorders (TMD)
Occlusal interventions for managing temporomandibular disorders (2024) · Cochrane
Listed in Summary of findings 5 as 'Not reported'; this outcome was not reported by any included study for this comparison.0 studiesNo studies
Intervention NR
Serum vitamin D (25(OH)D): ECC vs caries-free · Region: Asia (Fig 4)
The Association Between Vitamin D and Early Childhood Caries: A Systematic Review and Meta-Analysis. (2024)
Mean difference -14.14 [-15.37, -12.90]5 studiesUngraded
Oral health education/promotion (oral hygiene advice plus diet and feeding practice advice) combined with clinical treatment for mother's dentition (basic restorative and preventive; 1 trial included CHX varnish application) vs Standard care
dmfs index score · For interventions, pregnant women and mothers of infants in the first year of life; for outcomes, children up to 6…
Interventions with pregnant women, new mothers and other primary caregivers for preventing early childhood… (2024) · Cochrane
dmfs was listed in the SoF table but not assessed (not reported for this comparison).0 studiesNo studies
Silver diamine fluoride (SDF) vs Atraumatic restorative treatment (ART) with glass ionomer cement (GIC) or glass ionomer material
Dental pain or sensitivity · Children and adults (with or without carious lesions) · 3 months, Children
Topical silver diamine fluoride (SDF) for preventing and managing dental caries in children and adults (2024) · Cochrane
OR 0.16 [0.02, 1.32]1 study · 234 participantsVery low
SDF (given at a particular frequency, concentration, or duration) vs SDF (given at a different frequency, concentration, or duration)
Caries arrest · Children and adults (with or without carious lesions) · 12 to 30 months, Primary dentition
Topical silver diamine fluoride (SDF) for preventing and managing dental caries in children and adults (2024) · Cochrane
In 1 study (45 children), 4 applications of 38% SDF at 1-monthly intervals resulted in fewer surfaces with active caries compared with 2 applications at 6-monthly intervals (MD 1.04 surfaces, 95% CI 0.23 to 1.85), and…4 studies · 1360 participantsVery low
Postoperative systemic antibiotics (phenoxymethylpenicillin/penicillin VK, 7-day course), partial or total chemo-mechanical debridement and analgesics vs Matched placebo, partial or total chemo-mechanical debridement and analgesics
Swelling at 48 hours · Adults with a symptomatic necrotic tooth or localised acute apical abscess (no signs of spreading infection or… · 48 hours
Systemic antibiotics for symptomatic apical periodontitis and acute apical abscess in adults (2024) · Cochrane
SMD 0.04 [-0.47, 0.55]2 studies · 61 participantsUngraded
Amorphous calcium phosphate (ACP)-containing light-cure adhesive vs Conventional adhesive (Transbond XT)
Enamel demineralization (DIAGNOdent) · Patients undergoing fixed orthodontic (fixed appliance) treatment (adolescents and adults, ages 12 to 35) · 1 and 6 months
Can Orthodontic Adhesive Systems Inhibit the Formation and Development of White Spot Lesions During Fixed… (2024)
Alshammari 2019 (1 triple-blinded RCT, 26 patients / 255 teeth): DIAGNOdent demineralization scores were lower with ACP than control at 1 month (2.58 +/-1.11 vs 3.39 +/-1.29) and 6 months (3.41 +/-1.11 vs 4.32…1 study · 26 participantsUngraded
Occlusal splint vs Pharmacological therapy
Recurrence rate · People with temporomandibular disorders (TMD)
Occlusal interventions for managing temporomandibular disorders (2024) · Cochrane
Listed in Summary of findings 6 as 'Not reported'; this outcome was not reported by any included study for this comparison.0 studiesNo studies
Slum / urban-disadvantaged setting vs Non-slum urban / general-urban / national population
Dental service utilisation within the past year · Adult residents of slums and non-slum urban settings of LMICs · Past 12 months
Systematic review of oral health in slums and non-slum urban settings of Low and Middle-Income Countries… (2024)
Utilisation within the preceding year ranged from 4% to 72% (e.g., Osuh 4%; Hewlett 10%; Rezaei 60% for treatment and 10% for check-ups; Olutola 72%).NRUngraded
Occlusal splint vs Pharmacological therapy
Discomfort · People with temporomandibular disorders (TMD)
Occlusal interventions for managing temporomandibular disorders (2024) · Cochrane
Listed in Summary of findings 6 as 'Not reported'; this outcome was not reported by any included study for this comparison.0 studiesNo studies
Highest BMI category (overweight/obese) vs Lowest BMI category (normal weight/underweight)
Dental caries / early childhood caries (ECC) · Children (approx. 4-18 years) · Adjustment for age: yes
Childhood obesity in relation to risk of dental caries: a cumulative and dose-response systematic review and… (2024)
OR 1.04 [0.84, 1.30]6 studiesUngraded
Tandem traction bow appliance vs Untreated control (no treatment)
ANB · Children and adolescents (aged 16 years or younger) with prominent lower front teeth (Class III malocclusion) · End of treatment
Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children (2024) · Cochrane
MD 1.70 [1.09, 2.31]1 study · 30 participantsUngraded
Silver diamine fluoride (SDF; 38% in most trials, 30% in three) vs Sodium fluoride varnish (5% NaF)
Caries arrestment at the surface level · Children and adults with active dental caries (aged 1-50; mostly preschool/school children with primary dentition) · 12 to 18 months, SDF vs NAF
The role of silver diamine fluoride as dental caries preventive and arresting agent: a systematic review and… (2024)
OR 1.46 [0.71, 2.98]2 studies · 3541 participantsUngraded
Facemask vs Untreated control (no treatment)
Self-esteem (Piers-Harris self-concept scale) · Children and adolescents (aged 16 years or younger) with prominent lower front teeth (Class III malocclusion) · 3-year follow-up
Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children (2024) · Cochrane
MD 0.60 [-2.57, 3.77]1 study · 63 participantsUngraded
Intervention NR
Overall success (composite of clinical and radiographic success) · Immature teeth, unspecified/mixed diagnosis
Efficacy of pulpotomy for permanent teeth with carious pulp exposure: A systematic review and meta-analysis… (2024)
Proportion 0.888 [0.816, 0.945]6 studiesUngraded
Buccal fat pad graft vs Extended nasolabial flap
Maximal mouth opening (interincisal distance) · People of any age with a confirmed diagnosis, by clinical examination and biopsy, of oral submucous fibrosis (OSF) · More than 6 months
Interventions for managing oral submucous fibrosis (2024) · Cochrane
MD 6.50 [-10.72, 23.72]1 study · 8 participantsVery low
Facemask with rapid maxillary expansion (RME) vs Facemask with alternating rapid maxillary expansion and constriction (Alt-RAMEC)
ANB · Children and adolescents (aged 16 years or younger) with prominent lower front teeth (Class III malocclusion) · End of treatment
Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children (2024) · Cochrane
MD -0.46 [-1.03, 0.10]4 studies · 131 participantsLow
Antibacterial S. mutans reduction only in Farzanegan (chitosan+TiO2); Mollabashi (TiO2-only) showed no significant antibacterial effect - not attributable to TiO2 alone vs Conventional adhesive/composite (Transbond XT)
Antibacterial effect (Streptococcus mutans count, real-time PCR) · Patients undergoing fixed orthodontic (fixed appliance) treatment (adolescents and adults, ages 12 to 35) · 1 day to 6 months, Antibacterial (S. mutans)
Can Orthodontic Adhesive Systems Inhibit the Formation and Development of White Spot Lesions During Fixed… (2024)
Two RCTs gave conflicting antibacterial results: Farzanegan 2021 reported a significant decrease in S. mutans with the chitosan plus TiO2 adhesive (p=0.01 lateral incisors; p=0.001 second premolars); Mollabashi 2022…2 studies · 64 participantsUngraded
Occlusal splint vs Pharmacological therapy
Severity of joint noise · People with temporomandibular disorders (TMD)
Occlusal interventions for managing temporomandibular disorders (2024) · Cochrane
Listed in Summary of findings 6 as 'Not reported'; this outcome was not reported by any included study for this comparison.0 studiesNo studies
Intervention NR
Overall success (composite of clinical and radiographic success) · Partial pulpotomy, normal pulp/reversible pulpitis
Efficacy of pulpotomy for permanent teeth with carious pulp exposure: A systematic review and meta-analysis… (2024)
Proportion 0.920 [0.879, 0.954]4 studiesUngraded