Restoration Materials and Secondary Caries Using an In Vitro Biofilm Model

Abstract

This in vitro study investigated whether restoration materials and adhesives influence secondary caries formation in gaps using a short-term in vitro biofilm model. Sixty enamel-dentin blocks were restored with 6 different restoration materials with or without adhesives (n = 10 per group) with a gap: 1) Clearfil AP-X composite, 2) Clearfil AP-X composite + SE Bond, 3) Clearfil AP-X composite + ProtectBond, 4) Filtek Silorane composite, 5) Filtek Silorane composite + Silorane System adhesive, or 6) Tytin amalgam. Specimens were subjected to an intermittent 1% sucrose biofilm model for 20 days to create artificial caries lesions. Lesion progression in the enamel-dentin next to the different materials was measured in lesion depth (LD) and mineral loss (ML) using transversal wavelength independent microradiography (T-WIM). A regression analysis was used to compare the LD and ML of the different restoration materials at 4 measurement locations: 1 location at the surface of the enamel, 1 location at the wall of the enamel, and 2 locations at the wall of the dentin. A statistically significant effect of AP-X composite with Protect Bond was found for LD and ML at the WallDentin1 location, leading to less advanced wall lesions. An additional finding was that gap size was also statistically significant at the 2 wall locations in dentin, leading to increasing lesion progression with wider gaps. In conclusion, adhesives can influence wall lesion development in gaps. Protect Bond showed significantly less caries progression compared to bare restoration materials or other adhesives in this short-term in vitro biofilm model.

Secondary caries, mind the gap!

“…This implies that ions released from the amalgam rather than corrosive products may be the reason for the reduced secondary caries development, or that composite materials have properties that cause more secondary caries development. In our previous in vitro study we did not observe amalgam to have lower secondary caries progression in dentin compared to composite materials (Kuper et al, 2015). In that study gaps were larger: an average of 356 µm as compared to an average of 215 µm in the present study.…”

“…In recent studies, which compared secondary caries development next to several restorative materials in vitro (Kuper et al, 2015) and in situ (van de Sande et al, 2014) amalgam was not found to be associated with lower secondary caries progression in dentin compared to composite materials, but in both studies it was shown that certain types of composite materials have a tendency for more secondary caries development. If composites really are more susceptible to secondary caries development than amalgam, does this susceptibility also vary between different types of composite?…”

Minimal Gap Size and Dentin Wall Lesion Development Next to Resin Composite in a Microcosm Biofilm Model

“…An increment of LD and ML was expected with the increase of gap size, but it was not observed in the present study. In a previous in vitro study , Kuper et al [2015] found an association between gap size and wall lesion development using the same biofilm model. However, in that study gap sizes varied roughly between 213 and 578 μm.…”

Wall-lesion development in gaps: The role of the adhesive bonding material

“…A recent in vitro study reported that the type of bonding material could influence wall lesion development in gaps, with a protective effect of an antibacterial bonding agent on caries lesion development. 12 Those bonding agents were developed with the promise of having anti-caries properties through the presence of an bacterial inhibitor monomer in its composition.…”