What do systematic reviews say?

Fluoride mouthrinse (any fluoride agent, concentration, volume, frequency or technique; swished and expectorated, not swallowed) vs placebo or no treatment

• Fluoride mouthrinses for preventing dental caries in children and adolescents 2016 · Cochrane All outcomes

  At least 1 year/school year
  One trial (Rugg-Gunn 1973) reported incompletely on oral soft tissue irritation/signs of sensitivity (allergic reaction): "no cases of mucosal hypersensitivity after periodical examinations of every subject". 434…
  1 study · 434 participants
  Very low

Fluoride gel (topically applied; operator- or self-applied; any fluoride agent/concentration; frequency at least once a year) vs placebo or no treatment

The review found no eligible studies for this question.

• Fluoride gels for preventing dental caries in children and adolescents 2015 · Cochrane All outcomes
  None of the studies reported this outcome.
  0 studies
  No studies found

Topical fluoride therapy (toothpaste, mouthrinse, gel or varnish; any fluoride agent/concentration; frequency at least once a year) vs placebo or no treatment

• Topical fluoride (toothpastes, mouthrinses, gels or varnishes) for preventing dental caries in children and adolescents 2003 · Cochrane All outcomes
  Data on adverse effects (stain score, proportion of children with tooth staining, signs of sensitivity in oral soft tissue, adverse symptoms such as nausea/vomiting, etching of enamel) were reported in only a few…
  Studies not reported
  GRADE not reported

Fluoride toothpaste vs Non-fluoride (0 ppm F) placebo toothpaste

• Fluoride toothpastes for preventing dental caries in children and adolescents 2003 · Cochrane All outcomes

  At least 1 year
  Oral soft tissue lesions reported in 3 trials, none of which with complete or useable data; all three stated "no lesions attributable to product use were noted".
  3 studies
  GRADE not reported