Microcomputed Tomography Evaluation of Volumetric Shrinkage of Bulk‐Fill Composites in Class II Cavities

Algamaiah, Hamad; Sampaio, Camila S.; Rigo, Lindiane Cogo; Janal, Malvin N.; Giannini, Marcelo; Bonfante, Estevam A.; Coelho, Paulo G.; Reis, Alessandra; Hirata, Ronaldo

doi:10.1111/jerd.12275

Cited by 47 publications

(31 citation statements)

References 40 publications

(126 reference statements)

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“…Unfortunately, neither of these tests provides information on the real flow of material due to polymerization shrinkage. The nondestructive volumetric evaluation method of polymerization shrinkage using microcomputed tomography (micro-CT) scans displays areas of debonding and leakage around restorations but not internal displacement movements [13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Shrinkage vectors in flowable bulk-fill and conventional composites: bulk versus incremental application

et al. 2020

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Objectives Sufficient depth of cure allows bulk-fill composites to be placed with a 4-mm thickness. This study investigated bulk versus incremental application methods by visualizing shrinkage vectors in flowable bulk-fill and conventional composites. Materials and methods Cylindrical cavities (diameter = 6 mm, depth = 4 mm) were prepared in 24 teeth and then etched and bonded with OptiBond FL (Kerr, Italy). The composites were mixed with 2 wt% radiolucent glass beads. In one group, smart dentin replacement (SDR, Dentsply) was applied in bulk "SDR-bulk" (n = 8). In two groups, SDR and Tetric EvoFlow (Ivoclar Vivadent) were applied in two 2-mm-thick increments: "SDR-incremental" and "EvoFlow-incremental." Each material application was scanned with a micro-CT before and after light-curing (40 s, 1100 mW/cm 2), and the shrinkage vectors were computed via image segmentation. Thereafter, linear polymerization shrinkage, shrinkage stress and gelation time were measured (n = 10). Results The greatest shrinkage vectors were found in "SDR-bulk" and "SDR-increment2," and the smallest were found in "SDR-increment1-covered" and "EvoFlow-increment1-covered." Shrinkage away from and toward the cavity floor was greatest in "SDR-bulk" and "EvoFlow-increment2," respectively. The mean values of the shrinkage vectors were significantly different between groups (one-way ANOVA, Tamhane's T2 test, p < 0.05). The linear polymerization shrinkage and shrinkage stress were greatest in Tetric EvoFlow, and the gelation time was greatest in "SDR-bulk." Conclusions The bulk application method had greater values of shrinkage vectors and a higher debonding tendency at the cavity floor. Clinical relevance Incremental application remains the gold standard of composite insertion.

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Section: Introductionmentioning

confidence: 99%

Shrinkage vectors in flowable bulk-fill and conventional composites: bulk versus incremental application

et al. 2020

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“…Recently, a new class of composite resins named bulk-fill resins has been introduced in the market. The new material has adequate degree of conversion, 16 and microhardness, 17,18 low volumetric shrinkage 19 and a high depth of cure, 20 and could be an alternative to conventional composite resins for root reinforcement. 16,17,18,21,22,23,24 However, published studies with bulk-fill resins were performed in coronal dentin and no study has investigated their performance for reinforcement of flared root canals.…”

Section: Introductionmentioning

confidence: 99%

Bond strength values of fiberglass post to flared root canals reinforced with different materials

et al. 2018

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The aim of this study was to compare in vitro the bond strength (BS) between fiberglass posts and flared root canals reinforced with different materials. The roots of 48 premolars were endodontically treated. After one week, the root canals were prepared to simulate an oversized root canal, except for the positive control group (PCG), which was cemented with a prefabricated fiber post (PFP) compatible with the root canal size, simulating an ideal adaptation. The other samples (n=8/group) were used to test alternative restorative techniques for filling root canals: negative control group (NCG [PFP with a smaller diameter than of the root canal]), composite resin group - CRG, bulkfill group - BFG, self-adhesive cement group - SAG, and glass ionomer group - GIG. The posts were cemented and after 1 week, each root was sectioned transversely into six 1-mm thick discs and the push-out test was done to evaluate the BS. Data were analyzed by two-way repeated measures ANOVA and Tukey's tests (α=0.05). The highest BS value was observed for PCG. The NCG and the GIG groups showed the lowest BS values. Root reinforcement with conventional and bulk-fill composite resins showed the highest BS values; however, the bulk-fill resin was the only treatment able to maintain high BS values in all regions of the root canal. The self-adhesive cement showed intermediate results between CRG and GIG. Root reinforcement with bulk-fill composite resin is an effective option for flared root canals before cementation of a prefabricated fiber post.

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“…The changes in monomer and organic matrix of these composites reduce polymerization shrinkage stresses upto 70%. [ 9 10 ] Thus, problems related to polymerization shrinkage such as gap formation causing secondary caries, pulp irritation, and cuspal deflection due to high “C” factor can be minimized. [ 11 12 ]…”

Section: Introductionmentioning

confidence: 99%

Effect of intratooth location and thermomechanical cycling on microtensile bond strength of bulk-fill composite resin

et al. 2018

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Context:The initial bond strength and potential durability of an adhesive restoration are significantly affected by regional variations in dentin composition.Aim:The aim of this study is to evaluate the influence of dentin location and thermomechanical cyclic loading on microtensile bond strength of bulk-fill composite resin to coronal dentin.Materials and Methods:Disto-occlusal cavity preparations were done on 60 extracted human mandibular molars with pulpal floor depth of 1.5 and 3.5 mm for superficial and deep dentin and 1.5 mm axial wall depth and are restored with bulk-fill restorative composite. Bond strength evaluation was done using universal testing machine, and mode of bond failure was observed under scanning electron microscope.Statistical Analysis:Statistical analyses were done using ANOVA and Tukey's multiple post hoc test. For comparison of failure mode, Mann–Whitney U-test was used.Results:Superficial dentin has shown higher bond strength compared to deep dentin and gingival wall dentin (P = 0.001). The bond strength values decreased with the thermomechanical cycling (P = 0.001). Deep dentin and gingival dentin have exhibited more of adhesive failures.Conclusion:Bond strength of bulk-fill composite was negatively influenced by the depth of dentin and thermomechanical loading.

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Microcomputed Tomography Evaluation of Volumetric Shrinkage of Bulk‐Fill Composites in Class II Cavities

Cited by 47 publications

References 40 publications

Shrinkage vectors in flowable bulk-fill and conventional composites: bulk versus incremental application

Shrinkage vectors in flowable bulk-fill and conventional composites: bulk versus incremental application

Bond strength values of fiberglass post to flared root canals reinforced with different materials

Effect of intratooth location and thermomechanical cycling on microtensile bond strength of bulk-fill composite resin

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