What do systematic reviews say?

One-to-one advice on sugar restriction: detailed information on the sugar content of foods, with instruction to refrain from sugar-containing foods between meals and to reduce sugar in main meals (6-week sugar restriction) vs No advice on sugar restriction

• One‐to‐one dietary interventions undertaken in a dental setting to change dietary behaviour 2012 · Cochrane All outcomes

  Follow-up at 3, 6 and 12 weeks
  Table 5, mean (SD) intakes/day between meals: intervention 6.7 (1.9) baseline, 0.8 (1.0) at 3 weeks, 0.9 (1.0) at 6 weeks, 5.6 (3.0) at 12 weeks; control 5.3 (2.3), 5.2 (2.9), 4.6 (3.5), 4.7 (1.5). Significant…
  1 study · 20 participants
  GRADE not reported

One-to-one advice on sugar restriction: detailed information on the sugar content of foods, with instruction to refrain from sugar-containing foods between meals and to reduce sugar in main meals (6-week sugar restriction) vs No advice on sugar restriction

• One‐to‐one dietary interventions undertaken in a dental setting to change dietary behaviour 2012 · Cochrane All outcomes

  Follow-up at 3, 6 and 12 weeks
  Table 5, mean (SD) intakes/day at main meals: intervention 2.8 (0.5) baseline, 0.7 (0.7) at 3 weeks, 0.8 (0.9) at 6 weeks, 2.3 (0.8) at 12 weeks; control 1.9 (1.1), 1.9 (1.2), 1.9 (1.1), 2.0 (0.9). Significant…
  1 study · 20 participants
  GRADE not reported

One-to-one advice on sugar restriction: detailed information on the sugar content of foods, with instruction to refrain from sugar-containing foods between meals and to reduce sugar in main meals (6-week sugar restriction) vs No advice on sugar restriction

• One‐to‐one dietary interventions undertaken in a dental setting to change dietary behaviour 2012 · Cochrane All outcomes

  Follow-up at 3, 6 and 12 weeks
  Table 5, total mean (SD) intakes/day: intervention 9.5 (1.9) baseline, 1.6 (1.4) at 3 weeks, 1.8 (1.5) at 6 weeks, 7.8 (3.5) at 12 weeks; control 7.2 (2.6), 7.1 (3.7), 6.5 (4.2), 6.7 (2.2). Significant reduction versus…
  1 study · 20 participants
  GRADE not reported

Sugary drinks/sweets consumption vs Not applicable (single-group prevalence)

About 70% of children with caries in LMICs consumed sugary drinks/sweets (pooled prevalence 0.697, 95% CI 0.478 to 0.877; 7 studies; very high heterogeneity; not GRADE-rated).

• Individual, Family, and Socioeconomic Contributors to Dental Caries in Children from Low- and Middle-Income Countries. 2022 All outcomes

  Low- and middle-income countries (Brazil, Nigeria, Cambodia, Tanzania, Mexico, Ethiopia)
  Prevalence 0.6974 [0.4784, 0.8773]
  7 studies
  GRADE not reported

Sugary drinks/sweets consumption vs Children without dental caries

Sugary drinks/sweets consumption was associated with about twice the odds of dental caries in LMIC children (OR 2.04, 95% CI 1.59 to 2.60; 7 studies; not GRADE-rated).

• Individual, Family, and Socioeconomic Contributors to Dental Caries in Children from Low- and Middle-Income Countries. 2022 All outcomes

  Low- and middle-income countries (Brazil, Nigeria, Cambodia, Tanzania, Mexico, Ethiopia)
  OR 2.04 [1.59, 2.60]
  7 studies · 3653 participants
  GRADE not reported

Consumption of xylitol chewing gum by women (mothers) vs No chewing gum

Xylitol sugar-free gum significantly reduced plaque quantity versus no-gum/control (SMD -0.743, 95% CI -1.148 to -0.338), with high heterogeneity (I2 = 86.0%; ungraded).

• A Systematic Review and Meta-Analysis of the Role of Sugar-Free Chewing Gum on Plaque Quantity in the Oral Cavity. 2022 All outcomes

  End of study (last reported time point; study durations 4 days to 2 years) · Community, residential care homes, and schools; predominantly adults
  SMD -0.743 [-1.148, -0.338]
  7 studies
  GRADE not reported

A 10-minute film followed by the same 30-minute one-to-one hygienist instruction on sugar consumption and dental health, plus oral hygiene, fluoride and regular visits (a multi-intervention) vs No special instructions (control)

• One‐to‐one dietary interventions undertaken in a dental setting to change dietary behaviour 2012 · Cochrane All outcomes

  6 to 12 months
  Table 3, mean (SD) sugar consumption (1-5 scale): film-plus-instruction group 3.53 (1.27) at baseline to 3.06 (1.12) at follow-up (significant versus baseline); control 2.89 (0.99) to 2.88 (1.27). Results judged…
  1 study
  GRADE not reported

30 minutes of one-to-one instruction by a dental hygienist covering the relationship between sugar consumption and dental health, plus oral hygiene, fluoride and regular dental visits (a multi-intervention) vs No special instructions (control)

• One‐to‐one dietary interventions undertaken in a dental setting to change dietary behaviour 2012 · Cochrane All outcomes

  6 to 12 months
  Table 3, mean (SD) sugar consumption (1-5 scale): instruction group 3.41 (1.50) at baseline to 3.58 (1.07) at follow-up (significant versus baseline); control 2.89 (0.99) to 2.88 (1.27). The review judges the results…
  1 study
  GRADE not reported

Sugar consumption (higher sugar intake) vs No sugar consumption (lower/no intake)

Higher sugar consumption is associated with early childhood caries in children under 6 years: pooled OR 1.59 (95% CI 1.50 to 1.68) from 9 cohort studies with no heterogeneity (I2=0%); the body of evidence was not GRADE-rated (ungraded).

• Sugar consumption and early childhood caries: a systematic review and meta-analysis of cohort studies. 2025 All outcomes

  Outcome (ECC) assessed from 9 months to 5 years of age · Population-based birth and childhood cohort studies; multiple countries (Europe, Brazil, Asia, Australia, USA); mostly high-income, six in developing countries (Brazil, Thailand), none in low-income countries · Overall (all 9 meta-analyzed studies pooled)
  OR 1.59 [1.50, 1.68]
  9 studies
  GRADE not reported

High-frequency sugar consumption (three or more times daily) vs Low sugar intake (fewer than three times daily)

In primary dentition, high-frequency sugar consumption was associated with slightly higher, non-significant odds of caries (OR 1.13, 95% CI 0.23 to 5.44), with high heterogeneity (I2=83%; ungraded).

• A systematic review and meta-analysis of the association between sugar intake and dental caries in Nigeria. 2024 All outcomes

  Community and school-based observational studies in Nigeria (12 of 14 in Southwest Nigeria) · Primary dentition
  OR 1.13 [0.23, 5.44]
  2 studies
  GRADE not reported

High-frequency sugar consumption (three or more times daily) vs Low sugar intake (fewer than three times daily)

In permanent dentition, high-frequency sugar consumption was associated with non-significant 15% higher odds of caries (OR 1.15, 95% CI 0.88 to 1.52), with no heterogeneity (I2=0%; ungraded).

• A systematic review and meta-analysis of the association between sugar intake and dental caries in Nigeria. 2024 All outcomes

  Community and school-based observational studies in Nigeria (12 of 14 in Southwest Nigeria) · Permanent dentition
  OR 1.15 [0.88, 1.52]
  4 studies
  GRADE not reported

High-frequency sugar consumption (three or more times daily) vs Low sugar intake (fewer than three times daily)

High-frequency sugar consumption was associated with 18% higher but non-significant odds of dental caries in Nigeria (OR 1.18, 95% CI 0.87 to 1.59; I2=36%; ungraded).

• A systematic review and meta-analysis of the association between sugar intake and dental caries in Nigeria. 2024 All outcomes

  Community and school-based observational studies in Nigeria (12 of 14 in Southwest Nigeria) · Overall (all dentitions pooled)
  OR 1.18 [0.87, 1.59]
  7 studies
  GRADE not reported

Gum chewing (sugar-free) vs No chewing gum

Sugar-free chewing gum significantly reduced plaque quantity versus no-gum/control (SMD -0.778, 95% CI -1.167 to -0.390), with high heterogeneity (I2 = 86.6%) and no GRADE rating (ungraded).

• A Systematic Review and Meta-Analysis of the Role of Sugar-Free Chewing Gum on Plaque Quantity in the Oral Cavity. 2022 All outcomes

  End of study (last reported time point; study durations 4 days to 2 years) · Community, residential care homes, and schools; predominantly adults
  SMD -0.778 [-1.167, -0.390]
  7 studies
  GRADE not reported
• A Systematic Review and Meta-Analysis of the Role of Sugar-Free Chewing Gum on Plaque Quantity in the Oral Cavity. 2022 All outcomes

  End of study (last reported time point; study durations 4 days to 2 years) · Community, residential care homes, and schools; predominantly adults · Sensitivity analysis (pre-post correlation set to 0.95 for the SFG group)
  SMD -1.098 [-1.539, -0.656]
  7 studies
  GRADE not reported

Frequent sugary food intake at night vs No nighttime sugary intake

Nighttime sugary food intake was associated with higher odds of ECC (OR 1.104; source CI garbled).

• Prevalence and risk factors for early childhood caries in North Africa: a systematic review and meta-analysis. 2025 All outcomes

  Tunisia (Chouchene 2022) · At night only
  OR 1.104 [1.167, 2.826]
  1 study
  GRADE not reported

Xylitol-only sugar-free chewing gum vs Pooled controls: no gum, placebo/control gum, probiotic, or fluoride varnish

Xylitol-only sugar-free gum significantly reduced Streptococcus mutans load versus pooled controls (SMD -0.46, 95% CI -0.64 to -0.28; 12 trials, I2 43%); certainty not formally graded.

• A systematic review and meta-analysis of the role of sugar-free chewing gum on Streptococcus mutans. 2021 All outcomes

  Final/end-of-study time point (follow-up 2 weeks to 18 months) · Schools, kindergartens, universities and community settings; adults and children; multiple countries · Overall (vs all controls)
  SMD -0.46 [-0.64, -0.28]
  12 studies · 1295 participants
  GRADE not reported

Gum chewing (sugar-free) vs Pooled controls: no gum, placebo/control gum, probiotic, or fluoride varnish

In a sensitivity analysis assuming a 0.95 baseline-to-endpoint correlation for the sugar-free gum arm, the effect remained significant (SMD -0.55, 95% CI -0.80 to -0.30; 13 trials, I2 73%); certainty not formally graded.

• A systematic review and meta-analysis of the role of sugar-free chewing gum on Streptococcus mutans. 2021 All outcomes

  Final/end-of-study time point (follow-up 2 weeks to 18 months) · Schools, kindergartens, universities and community settings; adults and children; multiple countries · Sensitivity analysis: baseline-to-endpoint correlation 0.95 for SFG arm
  SMD -0.55 [-0.80, -0.30]
  13 studies · 1335 participants
  GRADE not reported
• A systematic review and meta-analysis of the role of sugar-free chewing gum on Streptococcus mutans. 2021 All outcomes

  Final/end-of-study time point (follow-up 2 weeks to 18 months) · Schools, kindergartens, universities and community settings; adults and children; multiple countries · Overall (vs all controls)
  SMD -0.42 [-0.60, -0.25]
  13 studies · 1335 participants
  GRADE not reported

Xylitol (low-intensity sweetener/sugar alcohol) in food products (chewing gum, milk, candy, or tablets) vs Sorbitol (low-intensity sweetener)

Xylitol and sorbitol did not differ significantly for Mutans streptococci in saliva (SMD -0.16, 95% CI -0.44 to 0.12; 2 trials, P=.25); not GRADE-rated.

• Clinical Effects of Sugar Substitutes on Cariogenic Bacteria: A Systematic Review and Meta-Analysis. 2024 All outcomes

  Post-consumption endpoint (varied durations across trials) · All age groups, generally healthy; multiple countries; sugar substitutes delivered as chewing gum, milk, candy, or tablets · Xylitol gum vs sorbitol gum (2 studies)
  SMD -0.16 [-0.44, 0.12]
  2 studies · 201 participants
  GRADE not reported

Xylitol (low-intensity sweetener/sugar alcohol) in food products (chewing gum, milk, candy, or tablets) vs no intervention

Xylitol significantly reduced Mutans streptococci in dental plaque compared with no treatment (SMD -0.73, 95% CI -1.09 to -0.37; 5 trials, I2=53%; not GRADE-rated).

• Clinical Effects of Sugar Substitutes on Cariogenic Bacteria: A Systematic Review and Meta-Analysis. 2024 All outcomes

  Post-consumption endpoint (trial durations 2 wk to 6 mo) · All age groups, generally healthy; multiple countries; sugar substitutes delivered as chewing gum, milk, candy, or tablets · Xylitol gum vs no treatment (5 studies, mixed ages)
  SMD -0.73 [-1.09, -0.37]
  5 studies · 308 participants
  GRADE not reported

Xylitol (low-intensity sweetener/sugar alcohol) in food products (chewing gum, milk, candy, or tablets) vs Sorbitol (low-intensity sweetener)

Xylitol reduced Mutans streptococci in dental plaque more than sorbitol (SMD -0.45, 95% CI -0.69 to -0.21; 4 trials, I2=7%); not GRADE-rated.

• Clinical Effects of Sugar Substitutes on Cariogenic Bacteria: A Systematic Review and Meta-Analysis. 2024 All outcomes

  Post-consumption endpoint (varied durations across trials) · All age groups, generally healthy; multiple countries; sugar substitutes delivered as chewing gum, milk, candy, or tablets · Xylitol vs sorbitol (4 studies)
  SMD -0.45 [-0.69, -0.21]
  4 studies · 323 participants
  GRADE not reported

Gum chewing (sugar-free) vs No chewing gum

Gum chewing reduced self-reported thirst in most studies (6 of 7 positive, 1 no effect); not meta-analyzed.

• The effect of gum chewing on xerostomia and salivary flow rate in elderly and medically compromised subjects: a… 2023 All outcomes

  Various (preoperative period to 3 + 1 months) · Haemodialysis units, elderly / geriatric care, cancer and palliative care, and xerostomia / hyposalivation clinics (studies from multiple countries)
  Narrative vote-count: of 7 studies measuring thirst, 6 found gum chewing reduced thirst [16,20,21,26,27,31] and 1 detected no effect [29].
  7 studies
  GRADE not reported