Marginal Adaptation and Depth of Cure of Flowable versus Packable Bulk-fill Restorative Materials: An In Vitro StudyMarginal Adaptation and Depth of Cure of Flowable versus Packable Bulk-fill Restorative Materials: An In Vitro Study

Abstract

Aim: To investigate the marginal adaptation and depth of cure of a flowable bulk-fill giomer (BEAUTIFIL Flow Plus X [BFP]), a flowable bulk-fill resin composite (PALFIQUE BULK FLOW [PBF]) bulk-fill resin composite, a packable bulk-fill giomer (BEAUTIFL-Bulk Restorative [BBR]), and two packable bulk-fill resin composites (X-tra fil [XF]) and (Filtek™ One Bulk Fill Restorative [FOB]).
 Materials and Methods: Twenty-five standardized class II cavities were prepared in the occlusomesial surfaces of maxillary premolars. A self-etching dental adhesive was used. All restorative materials were applied, and light cured according to their manufacturer's instructions. The teeth were subjected to 2500 thermal cycles between 5° C and 55° C. Epoxy resin replicas were obtained to examine the marginal by calculating the percentage of the continuous margin over the total margin length. using SEM at 200× magnification. For assessing the depth of cure, fifty specimens with 4 mm height were prepared. Vickers microhardness testing was used to assess the depth of cure was calculating the bottom-to-top ratio of each specimen. If this ratio reaches 0.80 or more, an adequate depth of cure is achieved.
 Results: Regarding marginal adaptation, there was no significant difference between different groups before (p=0.398) and after (p=0.644) thermocycling. Within all groups, there was a significant decrease in marginal adaptation after thermocycling (p<0.001). Regarding the depth of cure, all restorative materials achieved the required 0.8 bottom-to-top ratio. There was a significant difference between different groups (p<0.001). The highest value was found in BFP group (0.97±0.02), while the lowest value was found in BBR group (0.81±0.11).
 Conclusions: The marginal adaptation and depth of cure of bulk-fill giomer restorative materials are acceptable. Therefore, their use in restoration of 4-mm deep class II cavities is appealing.

Evaluation of surface microhardness and gingival marginal adaptation of three different bulk‐fill flowable resin composites: A comparative study

“…37,38 The findings of this study were that the surface microhardness and marginal adaptation results were altered by TMC in all tested Many studies had approved our conclusions. 5,6 They found that the marginal adaptation was impaired by the TMC as compared with the original state. This study is contradicted with previous studies.…”

“…structural defects. 6 Teeth were thoroughly cleansed with an ultrasonic scaler (woodpecker DTE D5 scaler unit, china) 41 and polished with nonfluoridated pumice to eliminate any debris. Teeth were disinfected for 24 h in 0.5% chloramine-T and kept in 0.1% thymol solution and refrigerated at 4 C until use.…”

“…Currently, bulk‐fill (BF) resin composites are stand out as a reliable treatment option for direct dental restorations 2–4 . BF materials are highly accepted due to a shortened and simplified procedure and less technique sensitive by reducing the number of composite layers and thus the curing time 5–9 . BF were developed by enhancing the translucency and adding of special modulators and more sensitive photoinitiators that allow greater light to pass through the material to ensure uniform polymerization and proper degree of conversion.…”

“…Additionally, the filler content is reduced and the size of the filler particles is increased. These modifications make the placement of 4–5‐mm‐thick increments feasible 6,10 …”

“…These modifications make the placement of 4-5-mm-thick increments feasible. 6,10 In addition, some chemical modifications have been made in BF composites to reduce polymerization shrinkage (PS) stress, 11 such as increasing the molecular weight of the monomers in their contents, adding new stress-relieving monomers, [12][13][14][15] using of more reactive photoinitiators, and the incorporation of different types of fillers, such as prepolymer particles and fiberglass rod segments. 16 All these options are to diminish PS and minimize the negative effects of PS stress, which results in a combination of deep curing and adequate marginal adaptation.…”