Wound infection · Adults with mandibular third molars requiring removal
It is very uncertain whether high-volume irrigation (~175 mL) changes wound infection compared with low-volume irrigation (~25 mL) (very low certainty).
1 finding from 1 review
Presence of dry socket · Adults with mandibular third molars requiring removal
It is very uncertain whether high-volume irrigation (~175 mL) changes alveolar osteitis compared with low-volume irrigation (~25 mL) (very low certainty).
1 finding from 1 review
Wound infection · Adults with mandibular third molars requiring removal
It is very uncertain whether mechanical (high-volume) irrigation changes wound infection compared with manual (low-volume) irrigation (very low certainty).
1 finding from 1 review
Presence of dry socket · Adults with mandibular third molars requiring removal
It is very uncertain whether mechanical (high-volume) irrigation changes alveolar osteitis compared with manual (low-volume) irrigation (very low certainty).
1 finding from 1 review
Spontaneous space closure · Children and adolescents after extraction of a mandibular permanent first molar (before eruption of the second molar)
In the mandible, mean patient age was not significantly associated with space closure odds (OR 0.59 per year; not GRADE-rated).
1 finding from 1 review
Fracture · general population
Non-linear positive dose-response: little change in overall fracture risk below ~1.5 mg/L drinking-water fluoride, with risk increasing above that threshold (RR 1.06, 1.19, 1.35 at 2.0, 3.0, 4.0 mg/L vs null); ungraded (4 studies).
4 findings from 1 review
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 1.2 mg/L vs null
RR 1.00 [0.80, 1.24]
4 studies
GRADE not reported
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 4.0 mg/L vs null
RR 1.35 [0.94, 1.95]
4 studies
GRADE not reported
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 3.0 mg/L vs null
RR 1.19 [0.87, 1.64]
4 studies
GRADE not reported
Show 1 more finding
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 2.0 mg/L vs null
RR 1.06 [0.80, 1.41]
4 studies
GRADE not reported
Risk of femoral fractures · general population
Femoral-fracture risk was mildly U-shaped: RR 0.86 at 0.5 mg/L rising to 1.06 at 1.8 mg/L drinking-water fluoride vs null; risk mostly below null across the range; ungraded.
2 findings from 1 review
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 1.8 mg/L vs null
RR 1.06 [0.67, 1.69]
Studies not reported
GRADE not reported
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 0.5 mg/L vs null
RR 0.86 [0.71, 1.05]
Studies not reported
GRADE not reported
Risk of fragility fractures · Male participants
In males (7 studies), fragility-fracture risk generally decreased with increasing fluoride: RR 0.83 (95% CI 0.72-0.97) at 0.57 mg/L to 0.87 (0.48-1.58) at 1.8 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 outcomesLong-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 · Males: drinking-water fluoride 1.8 mg/L vs null
RR 0.87 [0.48, 1.58]
7 studies
GRADE not reported
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 · Males: drinking-water fluoride 0.57 mg/L vs null
RR 0.83 [0.72, 0.97]
7 studies
GRADE not reported
Risk of fragility fractures · general population
Fragility-fracture risk overall was slightly U-shaped: RR 0.93 up to 0.9 mg/L, ~1.00 at 1.48 mg/L, 1.05 at 1.8 mg/L drinking-water fluoride vs null; ungraded.
5 findings from 1 review
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 up to 0.9 mg/L vs null
RR 0.93 [0.84, 1.02]
Studies not reported
GRADE not reported
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 1.8 mg/L vs null
RR 1.05 [0.82, 1.35]
Studies not reported
GRADE not reported
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 · Sensitivity (excluding high risk-of-bias studies): 0.8-1.5 mg/L vs null
RR 0.93 [0.72, 1.21]
Studies not reported
GRADE not reported
Show 2 more findings
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 1.48 mg/L vs null
RR 1.00 [0.82, 1.21]
Studies not reported
GRADE not reported
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 · Sensitivity (excluding high risk-of-bias studies): 1.8 mg/L vs null
RR 0.95 [0.70, 1.29]
Studies not reported
GRADE not reported
Lumbar spine bone mineral density (BMD) · general population
Spine BMD showed an inverted U-shaped association with fluoride (peak ~0.6 mg/L); excluding high risk-of-bias studies gave small positive MDs (e.g., 0.05 g/cm2, 95% CI 0.01-0.10, up to 2.27 mg/L); ungraded.
4 findings from 1 review
Show 1 more finding
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 · Sensitivity (excluding high risk-of-bias studies): above 2.27 mg/L vs null
MD 0.04 [-0.21, 0.30]
Studies not reported
GRADE not reported
Risk of fragility fractures · Females (all ages)
In females, fragility-fracture risk was U-shaped: lowest ~0.4 mg/L, rising above 0.9 mg/L (RR 0.84 at 0.34, 1.00 at 0.9, 1.13 at 1.1 mg/L vs null); ungraded.
3 findings from 1 review
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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: drinking-water fluoride 1.1 mg/L vs null
RR 1.13 [0.93, 1.37]
Studies not reported
GRADE not reported
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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: drinking-water fluoride 0.34 mg/L vs null
RR 0.84 [0.67, 1.07]
Studies not reported
GRADE not reported
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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: drinking-water fluoride 0.9 mg/L vs null
RR 1.00 [0.79, 1.27]
Studies not reported
GRADE not reported
Lumbar spine bone mineral density (BMD) · Females (all ages)
In females (low-to-moderate risk-of-bias studies), spine BMD rose then plateaued ~0.5 mg/L: MD 0.02 g/cm2 (95% CI -0.02-0.07) at 0.20 mg/L and 0.06 (-0.01-0.12) across 0.7-2.35 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 outcomesLong-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: 0.7-2.35 mg/L vs null
MD 0.06 [-0.01, 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 outcomesLong-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: 0.20 mg/L vs null
MD 0.02 [-0.02, 0.07]
Studies not reported
GRADE not reported
Risk of fragility fractures · Females aged over 50 years
In females over 50, fragility-fracture risk rose steeply from ~0.5 mg/L: RR 0.98 at 0.25, 1.00 at 0.45, and 1.26 (95% CI 1.10-1.46) at 1.0 mg/L drinking-water fluoride vs null; ungraded.
3 findings from 1 review
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 over 50 years: drinking-water fluoride 0.45 mg/L vs null
RR 1.00 [0.80, 1.24]
Studies not reported
GRADE not reported
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 over 50 years: drinking-water fluoride 0.25 mg/L vs null
RR 0.98 [0.83, 1.14]
Studies not reported
GRADE not reported
The association of fluoride exposure with bone density and fracture risk: a dose-response meta-analysis. 2025 All outcomesLong-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 over 50 years: drinking-water fluoride 1.0 mg/L vs null
RR 1.26 [1.10, 1.46]
Studies not reported
GRADE not reported
Hip/femoral bone mineral density (BMD) · general population
Hip BMD increased with fluoride in both sexes (linearly in males, non-linearly above ~1.2 mg/L in females); no numeric MD reported in text for the main analysis; ungraded.
1 finding from 1 review
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 outcomesLong-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 outcomesLong-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
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 outcomesLong-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 outcomesLong-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
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
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
Spine bone mineral density · Females (all ages)
Among females in low-to-moderate-risk-of-bias studies, the reported spine-BMD estimate above 2.35 mg/L water fluoride was MD 0.07 g/cm2 (95% CI 0.11 to 0.24; ungraded).
2 findings from 1 review
Adverse effects · Adults with head and neck cancer undergoing curative or adjuvant radiotherapy (at risk of osteoradionecrosis of the jaws)
1 finding from 1 review
Adverse effects were an outcome of interest in the study conducting this comparison, however no mention was made of the presence or absence of any adverse events
1 study · 220 participants
Very low