Findings

What do systematic reviews say?

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Evidence found and GRADE certainty

516 questions · 950 findings · 74 reviews · Dental caries

No studies found 35 · 3.7%GRADE not reported 831 · 87.5%Very low 38 · 4%Low 26 · 2.7%Moderate 13 · 1.4%High 7 · 0.7%

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

Hip/femoral bone mineral density (BMD) · Females (all ages)

In females (low-to-moderate risk-of-bias studies), hip BMD rose monotonically above ~0.9 mg/L: MD 0.04 g/cm2 (95% CI -0.03-0.12) up to ~2.3 mg/L and 0.09 (-0.09-0.27) at 4.0 mg/L 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 · Females, low-to-moderate risk-of-bias studies: up to ~2.3 mg/L vs null
    MD 0.04 [-0.03, 0.12]
    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 · Females, low-to-moderate risk-of-bias studies: 4.0 mg/L vs null
    MD 0.09 [-0.09, 0.27]
    Studies not reported
    GRADE not reported

Replacement of the defective restoration vs Repair of the defective restoration

Amalgam: Preference for replacement over repair - Scenario 5: open margin · Dentists managing a defective direct amalgam restoration (posterior occlusal Class I; standardized vignette of a 30-year-old,…

For a defective amalgam restoration with open margin, surveyed dentists most often preferred replacement over repair (pooled RR 5.14; p < 0.001); ungraded.

1 finding from 1 review

Genetically predicted DMFS (dental caries) vs Lower genetically predicted DMFS

Osteoporosis · European GWAS participants

The SVMR Weighted Median interval excluded the null.

3 findings from 1 review

Health expenditure per capita vs Higher vs lower per-capita health expenditure categories

Oral health-related quality of life · people aged 60 years and older living in the community

OHRQoL did not differ significantly across per-capita health-expenditure categories; no pooled estimate was reported in the text (ungraded).

1 finding from 1 review

Country-level edentulism prevalence (Global Burden of Disease) vs Low vs high edentulism prevalence

Oral health-related quality of life · people aged 60 years and older living in the community

OHRQoL did not differ significantly by country-level edentulism prevalence; no pooled estimate was reported in the text (ungraded).

1 finding from 1 review

Genetically predicted periodontitis vs Lower genetically predicted periodontitis liability

Forearm fracture · European-ancestry adults

Genetically predicted periodontitis had no causal effect on fracture of forearm (multivariable MR, OR 0.995).

2 findings from 1 review

Genetically predicted periodontitis vs Lower genetically predicted periodontitis liability

Femur fracture · European GWAS participants

The SVMR Weighted Median interval included the null.

3 findings from 1 review

Genetically predicted periodontitis vs Lower genetically predicted periodontitis liability

Postmenopausal osteoporosis with pathological fracture · European GWAS participants

The SVMR Weighted Median interval included the null.

3 findings from 1 review

Replacement of the defective restoration vs Repair of the defective restoration

Amalgam: Preference for replacement over repair - Scenario 3: secondary caries · Dentists managing a defective direct amalgam restoration (posterior occlusal Class I; standardized vignette of a 30-year-old,…

For a defective amalgam restoration with secondary caries, surveyed dentists most often preferred replacement over repair (pooled RR 6.94; p < 0.001); ungraded.

1 finding from 1 review

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

Genetically predicted periodontitis vs Lower genetically predicted periodontitis liability

Postmenopausal osteoporosis with pathological fracture · Postmenopausal women (European ancestry)

Genetically predicted periodontitis had no causal effect on postmenopausal osteoporosis with pathological fracture (single-variable MR, OR 1.014).

2 findings from 1 review

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

Genetically predicted DMFS (dental caries) vs Reference (1-SD lower genetically predicted DMFS)

Femur fracture · European-ancestry adults

Genetically predicted dental caries (DMFS) had no significant causal effect on fracture of femur (multivariable MR, OR 1.069).

2 findings from 1 review

Out-of-pocket health expenditure vs Lower vs higher out-of-pocket expenditure categories

Oral health-related quality of life · people aged 60 years and older living in the community

Lower out-of-pocket health expenditure was associated with better OHRQoL (83.9, 95% CI 75.2 to 92.6 vs 67.5, 95% CI 58.5 to 76.5); the difference was statistically significant (ungraded).

2 findings from 1 review

Genetically predicted pulp and periapical diseases vs Without pulp and periapical diseases (lower genetic liability)

Lacunar stroke · European-ancestry adults

Genetically predicted pulp and periapical diseases were associated with modestly higher odds of lacunar stroke (OR 1.20); ungraded MR, FDR-adjusted P 0.033.

1 finding from 1 review

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

Lumbar spine bone mineral density (BMD) · Females aged over 50 years

In females over 50, spine BMD showed an inverted U-shaped curve with a downward trend beginning at lower fluoride concentrations than in the overall analysis; no numeric MD 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 · Females >50, spine BMD dose-response
    Inverted U-shaped curve with a downward trend starting at lower fluoride concentrations than the overall analysis (no numeric MD reported in text)
    Studies not reported
    GRADE not reported