Does strontium play a role in the cariostatic activity of glass ionomer? Strontium diffusion and antibacterial activity.
OBJECTIVE
The aim of this work was to evaluate the activity of strontium ions on the main pathogens of the oral flora. The leaching of strontium from resin modified glass ionomer cements (RMGIC) was evaluated together with its uptake by superficial dental enamel.


METHODS
The antibacterial activity was measured by the growth inhibition method following exposure of supra- and sub-gingival bacteria to a range of strontium concentrations (0.19 moll(-1), 0.37 moll(-1), 0.74 moll(-1) and 1.11 moll(-1)). Strontium concentrations were analyzed chemically and migration at 5 microm and 15 microm depths was quantified by microprobe following Fuji Ortho LC application on the vestibular enamel of extracted teeth.


RESULTS
Strontium was found in appreciable amounts (0.8 wt.%) in superficial enamel, but in insignificant concentrations deeper in. At the same time, 8% fluoroapatite was formed in the enamel. Under our experimental conditions, strontium had no significant antibacterial activity; only one log reduction of activity was observed at the highest concentrations tested.


CONCLUSIONS
RMGIC releases strontium ions which are rapidly exchanged for calcium ions in the superficial enamel. No significant antibacterial activity was observed for strontium ions alone at the concentrations considered. However synergistic effects with fluoride could promote antibacterial activity.
Dabsie
Firas
F
Department of Biomaterials, Faculty of Odontology, University Toulouse III, 31062 Toulouse, France.
Gregoire
Geneviève
G
Sixou
Michel
M
Sharrock
Patrick
P
D000180:Acrylic Resins / Q000737:chemistry; D000190:Actinomyces / Q000187:drug effects; D016924:Actinomyces viscosus / Q000187:drug effects; D000293:Adolescent; D016976:Aggregatibacter actinomycetemcomitans / Q000187:drug effects; D000538:Aluminum Silicates / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001031:Apatites / Q000032:analysis; D002118:Calcium / Q000032:analysis; D002327:Cariostatic Agents / Q000737:chemistry / Q000494:pharmacology*; D002648:Child; D015169:Colony Count, Microbial; D001840:Dental Bonding; D003743:Dental Enamel / Q000737:chemistry; D004058:Diffusion; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D007779:Lactobacillus acidophilus / Q000187:drug effects; D007780:Lacticaseibacillus casei / Q000187:drug effects; D008422:Materials Testing; D016910:Orthodontic Brackets; D016966:Porphyromonas gingivalis / Q000187:drug effects; D018713:Prevotella intermedia / Q000187:drug effects; D019279:Resin Cements / Q000737:chemistry; D013291:Streptococcus / Q000187:drug effects; D013295:Streptococcus mutans / Q000187:drug effects; D016986:Streptococcus sobrinus / Q000187:drug effects; D013324:Strontium / Q000737:chemistry / Q000494:pharmacology*; D013997:Time Factors
D000180:Acrylic Resins; D000538:Aluminum Silicates; D000900:Anti-Bacterial Agents; D001031:Apatites; D002327:Cariostatic Agents; C095451:Fuji Ortho LC; D005899:Glass Ionomer Cements; D019279:Resin Cements; C025105:fluorapatite; D002118:Calcium; D013324:Strontium