Findings

What do systematic reviews say?

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Evidence found and GRADE certainty

3,801 questions · 4,079 findings · 473 reviews

No studies found 669 · 16.4%GRADE not reported 852 · 20.9%Very low 738 · 18.1%Low 903 · 22.1%Moderate 716 · 17.6%High 201 · 4.9%

Higher drinking-water fluoride exposure vs Null / lowest drinking-water fluoride exposure (reference)

Wrist fractures · general population

Wrist-fracture risk declined nearly linearly with increasing fluoride: RR 1.00 at 0.01 mg/L to 0.84 at 1.5 mg/L drinking-water fluoride vs null; ungraded.

2 findings from 1 review
  • The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomes
    Long-term / lifetime fluoride exposure · General population; 37 observational studies (1944-2024), predominantly North America (USA, Canada) and Northern Europe (Finland, Sweden), plus UK, Poland, Italy, Germany, China, Taiwan, South Korea, Ethiopia; exposure mainly community drinking-water fluoride · Drinking-water fluoride 1.5 mg/L vs null
    RR 0.84 [0.43, 1.65]
    Studies not reported
    GRADE not reported
  • The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomes
    Long-term / lifetime fluoride exposure · General population; 37 observational studies (1944-2024), predominantly North America (USA, Canada) and Northern Europe (Finland, Sweden), plus UK, Poland, Italy, Germany, China, Taiwan, South Korea, Ethiopia; exposure mainly community drinking-water fluoride · Drinking-water fluoride 0.01 mg/L vs null
    RR 1.00 [0.99, 1.01]
    Studies not reported
    GRADE not reported

Higher drinking-water fluoride exposure vs Null / lowest drinking-water fluoride exposure (reference)

Hip Fracture · general population

Overall hip-fracture risk showed little association with drinking-water fluoride and a nearly flat dose-response curve (narrow CI); no numeric RR reported in text; ungraded.

1 finding from 1 review
  • The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomes
    Long-term / lifetime fluoride exposure · General population; 37 observational studies (1944-2024), predominantly North America (USA, Canada) and Northern Europe (Finland, Sweden), plus UK, Poland, Italy, Germany, China, Taiwan, South Korea, Ethiopia; exposure mainly community drinking-water fluoride · Overall dose-response (0 to highest exposure)
    Curve indicated little association and was nearly flat, with a comparatively narrow 95% confidence band (no numeric RR reported in text)
    Studies not reported
    GRADE not reported

Dental cavity liner (e.g. calcium hydroxide, glass ionomer, resin-modified glass ionomer, or flowable composite) placed under the restoration vs No cavity liner or a different liner material

Secondary prevention of caries · Patients with deep caries lesions in mature or immature permanent (posterior) teeth, with no symptoms or reversible pulpitis

Cavity liners may make little or no difference to secondary caries prevention (~100% prevention across groups; low certainty).

1 finding from 1 review

Anorexia nervosa (as exposure; diagnosed by DSM-III/III-R/IV/V) vs Healthy controls

Salivary alpha-amylase · Patients with anorexia nervosa aged >=12 years (mean age ~18.4; entirely female in reported data), general community-dwelling population

There is no significant difference in salivary alpha-amylase between anorexia nervosa patients and healthy controls (MD 6.32 U/l, 95% CI -6.14 to 18.79; low certainty).

1 finding from 1 review

Anorexia nervosa (as exposure; diagnosed by DSM-III/III-R/IV/V) vs Healthy controls

Salivary flow rate (unstimulated) · Patients with anorexia nervosa aged >=12 years (mean age ~18.4; entirely female in reported data), general community-dwelling population

Anorexia nervosa probably reduces unstimulated salivary flow rate versus healthy controls (MD -0.27 ml/min, 95% CI -0.31 to -0.24; moderate certainty).

1 finding from 1 review

Anorexia nervosa (as exposure; diagnosed by DSM-III/III-R/IV/V) vs Healthy controls

Gingival (marginal) recession · Patients with anorexia nervosa aged >=12 years (mean age ~18.4; entirely female in reported data), general community-dwelling population

Gingival (marginal) recession was significantly higher in anorexia nervosa patients than controls in both reporting studies, but was not pooled or graded (ungraded).

1 finding from 1 review

Anorexia nervosa (as exposure; diagnosed by DSM-III/III-R/IV/V) vs Healthy controls

Dental erosion · Patients with anorexia nervosa aged >=12 years (mean age ~18.4; entirely female in reported data), general community-dwelling population

Dental erosion was more prevalent in anorexia nervosa patients than controls (low erosive-wear severity), but was not pooled or graded (ungraded).

1 finding from 1 review

Anorexia nervosa (as exposure; diagnosed by DSM-III/III-R/IV/V) vs Healthy controls

Plaque · Patients with anorexia nervosa aged >=12 years (mean age ~18.4; entirely female in reported data), general community-dwelling population

Anorexia nervosa patients tended to have higher plaque accumulation than healthy controls (significant in 2 of 3 studies), but results were not pooled or graded (ungraded).

1 finding from 1 review

Anorexia nervosa (as exposure; diagnosed by DSM-III/III-R/IV/V) vs Healthy controls

Caries experience · Patients with anorexia nervosa aged >=12 years (mean age ~18.4; entirely female in reported data), general community-dwelling population

Anorexia nervosa is associated with significantly higher caries experience (DMFT) than healthy controls (MD 2.00 teeth, 95% CI 0.87 to 3.13; low certainty).

1 finding from 1 review

Slum / urban-disadvantaged setting vs Non-slum urban / general-urban / national population

Ever utilised dental services · Adult residents of slums and non-slum urban settings of LMICs

Ever-use of dental services is low-to-moderate (17%-71%) and generally lower in slum/rural groups; ungraded.

1 finding from 1 review

Slum / urban-disadvantaged setting vs Non-slum urban / general-urban / national population

Periodontal disease prevalence · Adult residents of slums and non-slum urban settings of LMICs

Periodontal disease prevalence is high (23%-99%) across LMIC urban/slum populations; ungraded.

1 finding from 1 review

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-year dental service use varies widely (4%-72%); ungraded.

1 finding from 1 review

Slum / urban-disadvantaged setting vs Non-slum urban / general-urban / national population

Caries experience (mean DMFT) · Adult residents of slums and non-slum urban settings of LMICs

Mean DMFT ranges from 0.26 to 16.6 across LMIC urban/slum populations; ungraded.

1 finding from 1 review

Slum / urban-disadvantaged setting vs Non-slum urban / general-urban / national population

Dental trauma prevalence · Adult residents of slums and non-slum urban settings of LMICs

Dental trauma appears more common in urban and disadvantaged settings; ungraded, few studies.

1 finding from 1 review

Slum / urban-disadvantaged setting vs Non-slum urban / general-urban / national population

Use of toothbrush and toothpaste for mouth cleaning · Adult residents of slums and non-slum urban settings of LMICs

Toothbrush/paste is the commonest cleaning method but is used less in slum/disadvantaged/rural groups than urban/non-slum groups; ungraded.

1 finding from 1 review

Slum / urban-disadvantaged setting vs Non-slum urban / general-urban / national population

Pattern of dental service utilisation and barriers · Adult residents of slums and non-slum urban settings of LMICs

Dental service use is low, episodic and pain-driven, with widespread self-care and cost/funding barriers; ungraded.

1 finding from 1 review

Slum / urban-disadvantaged setting vs Non-slum urban / general-urban / national population

Frequency of mouth cleaning · Adult residents of slums and non-slum urban settings of LMICs

Twice-daily cleaning (recommended) is uncommon; most clean once, in the morning; ungraded.

1 finding from 1 review

Slum / urban-disadvantaged setting vs Non-slum urban / general-urban / national population

Oral disease burden, slum vs non-slum urban comparison · Adult residents of slums and non-slum urban settings of LMICs

Where compared, oral disease burden is generally higher in slums than non-slum urban/national populations (5 studies; 1 found no difference); ungraded.

1 finding from 1 review

Slum / urban-disadvantaged setting vs Non-slum urban / general-urban / national population

Dental caries prevalence · Adult residents of slums and non-slum urban settings of LMICs

Dental caries prevalence in LMIC urban/slum populations ranges widely (13%-76%); not GRADE-rated (narrative synthesis).

1 finding from 1 review