The principal reason for restoration failure is secondary caries in both permanent and primary dentition, which is responsible for 50-60% of all replacement restorations in the dental practice. In addition to plaque stagnation in the restoration and tooth surface interface, other factors contribute for the formation of secondary caries including: • Marginal gap formation between the restoration and the tooth surface allowing clinically undetectable leakage between the cavity wall and the filling; • Broken filling; • Loss of a part of the filling. An in-situ study showed that the percentage of streptococci in plaque on different materials was to be 13.7% on composite, 4.3% on amalgam and 1.1% on glass ionomer cement [1]. Another study showed up to eight times more microbes beneath composite restorations compared to amalgam [2]. Efficiency of restorative materials in their anticaries effects are as follow: Conventional GIC > metal-reinforced GIC “Cermet” > conventional amalgam > composite resin [3]. Research on dental restorative materials focuses on creating a bonded material such as combined the favorable properties of both glass-ionomer and composite resin (compomers), rather than incorporation of antimicrobial agent which may not compatible with the ingredients of the restorative material.

1. Svanberg M, Mjör IA , Orstavik D. Mutans streptococci in plaque from margins of amalgam, composite, and glass-ionomer restorations. J Dent Res 1990;69:861-4.

2. Heinrich A, Bernhardt O, Christian Splieth C, et al. Anaerobic microflora under class I and class II composite and amalgam fillings. Int Poster J Dent Oral Med 2000, Vol 2 No 3.

3. Hattab F.N, Mok, N.Y.C, Agnew E.C. Artificially formed caries-like lesions around restorative materials. Am J Dent Assoc 1989;118:193-7.

Thanks Faiez N. Hattab for the interesting answer and article references, particularly #2, (already 20 years ago...!) stating :

"...composites – in contrast to amalgam – do not have any antibacterial effects."

Moreover:

" The microflora under composite restorations had a great variety of anaerobes,.... similar to the microflora of infected root canals."

and further suggesting that :

"....inadaquate composite fillings can promote pulpal infection "!

If we seek back in 1980, ( 40 years ago...!) eminent researchers like

Bergenholtz, G., Cox, C.F., Loesche, W.J., Syed, S.A.: observed in

"Bacterial leakage around dental restorations: its effect on the dental pulp "

that: "results showed no bacterial leakage with ZOE fillings and subjacent pulp structures were normal". - " Where there were no demonstrable bacteria beneath the test material, the pulpal tissue was usually unaffected."

And concluded that : "... inflammatory cell infiltration were seen in conjunction with bacterial growth".

Resumed : NO BUGS = NO PROBLEMS

Thus dear Faiez N. Hattab , I still wonder why , as well explained in your answer : "Research on dental restorative materials focuses on creating a bonded material... rather than incorporation of antimicrobial agent " ??

Which is in fact one of the reason arised in my question : release or not release ?

Best Regards

Nicola