Table 3.

Nine studies excluded from the review.

Studies	Reason(s) for Exclusion
Sarijo et al. [31]	Ion release investigated for herbicide release, not release from dental materials.
Saha et al. [24]	Review on drug release; however, not dental related.
Kuthati et al. [32]	Review on drug release reporting only one dental study by Tammaro et al. [28], which is included in our review.
Mandal et al. [33]	Fluoride removal investigated.
Kameda et al. [34]	Fluoride removal investigated.
Delorme et al. [35]	Fluoride uptake and release investigated for water depollution.
Joshi et al. [36]	Layered double hydroxide not used in the study, mesoporous hectorites used.
Louvain et al. [37]	No fluoride release data published; the study was not dentally related.
Ma et al. [38]	Fluoride removal investigated.