Fracture resistance, gap and void formation in root‐filled mandibular molars restored with bulk‐fill resin composites and glass‐ionomer cement base

Abstract

Aim To evaluate fracture resistance and gap/void presence of root‐filled mandibular molars restored with 2 bulk‐fill and 1 conventional resin composites, with or without a glass‐ionomer cement (GIC) base. Methods Coronal access and mesio‐occlusal (MO) cavities were prepared, then root canal treatment was performed on 30 mol/L. The teeth were randomly divided, according to the cavity volume, into 6 experimental groups (N = 5) and restored with conventional/light‐cured (Ceram‐X), bulk‐fill/light‐cured (SureFil SDR) or bulk‐fill/dual‐cured (Core‐X Flow) with/without a 2‐mm thick GIC base. Gaps and voids (%) were determined using microcomputed tomography. Intact teeth and unrestored teeth were used as negative and positive controls. Fracture load (N) was determined using a universal testing machine. Results No significant difference in fracture resistance or gap/void formation was found among the 3 resin composites. GIC‐base groups revealed significantly lower fracture strength than intact teeth, while fracture strengths of no GIC‐base groups were not significantly different from intact teeth. GIC‐base groups revealed significantly more gaps and voids in the area of the GIC than the resin composite. Conclusion Conventional and bulk‐fill resin composites provided similar fracture resistance and gaps/voids in root‐filled molars with MO cavities. Placing a GIC base decreased fracture resistance and increased gap/void formation.

Fracture Resistance and Microleakage around Direct Restorations in High C-Factor Cavities

“…Although flowable composites generally shrink more than conventional paste-like composites, due to their higher amount of resin matrix [64], the subsequent shrinkage stress remains low in comparison [46,65]. Our findings are in contrast with those of Thongbai-On et al [66] or Park et al [16] who did not find significant difference between SDR and layered composite filling in terms of gap formation along the interphase. It must be noted that both of the cited studies investigated Class II MO/MOD cavities, which can be an explanation for the different outcomes.…”

Flexural strengths and porosities of coated or uncoated, high powder-liquid and resin-modified glass ionomer cements

“…The result is in correspondence to the study that investigated gaps and voids of HPL-GIC and RM-GIC when used as a base in restoration of endodontically treated teeth. 15 This phenomenon might be explained by the difference in viscosity between the two materials. From the specimen preparation, the author noticed that the viscosity of the HPL-GIC was relatively higher than the RM-GIC, which might cause more voids or air bubbles inside the material during mixing.…”

“… 14 Recent micro-CT tool is able to detect micro gaps and voids with the smallest effective voxel size of approximately 6 microns. 15 From our pilot study, we found that micro-CT could create a dry condition in the chamber during 3-D scanning. In addition, the dry condition was standardized if the scanning time was controlled.…”

Como as resinas do tipo bulk fill poderiam auxiliar na otimização de restaurações na saúde pública? Revisão crítica integrativa

“…Sejam aplicadas em lesões cervicais não cariosas ou em cavidades posteriores extensas, as resinas bulk fill apresentaram resultados satisfatórios, sem diferenças significativas em relação às convencionais (Loguercio et al, 2019;Canali et al, 2019). Isso é observado em estudos onde a bulk fill foi aplicada na confecção de núcleos de preenchimento em dentes tratados endodonticamente, avaliando-se resistência a fratura e formação de gaps (Thongbai-on et al, 2019).…”