Randomized Prospective Clinical Trial of Class II Restorations Using Low-shrinkage Flowable Resin Composite

The clinical performance of bulk-fill versus the incremental layered application of direct resin composite restorations: a systematic review

OBJECTIVES

To systematically review the scientific evidence comparing the clinical effectiveness of bulk-fill versus incrementally layered conventional resin composites and to evaluate if one method offers clear merits with specific clinical outcomes.

MATERIALS AND METHODS

Using relevant mesh terms and pre-established eligibility criteria in PubMed, Embase, Scopus and Web of Science, a thorough scientific search was conducted with an end-date of 30.04.2023. Randomized controlled clinical trials that involved the direct comparison of Class I and Class II resin composite restorations applied using incremental layering techniques versus bulk-filled in permanent teeth with an observation period of at least six months were considered. To evaluate the bias risk of the finalized records, a revised version of the Cochrane risk-of-bias tool for randomized trials was implemented.

RESULTS

Out of the 1445 records determined, 18 eligible reports were chosen for qualitative analysis. Data obtained was categorized as per, the cavity design, the intervention, the comparator(s), the methods of success/failure assessment, the outcomes, and follow-up. Two studies demonstrated an overall low-risk of bias, fourteen studies raised some concerns, and two studies exhibited high-risk.

CONCLUSION

Bulk filled resin composite restorations demonstrated clinical outcomes similar to those of incrementally layered resin composite restorations within a review interval of 6 months to 10 years.

Clinical effectiveness of alkasite versus nanofilled resin composite in the restoration of occlusal carious lesions in permanent molar teeth of children: a randomized clinical trial

PURPOSE

To evaluate and compare the clinical effectiveness of alkasite with nanofilled resin composite restorations for occlusal caries lesions in permanent molar teeth of children, at one-year follow-up.

METHODS

In this randomized controlled clinical trial with parallel design, 38 children aged 7-13 years with occlusal caries lesions on 59 first permanent molars were randomly allocated into two groups, Group 1: Filtek™ Z350XT (nanocomposite) and Group 2: Cention N^® (alkasite resin composite). The restorations were evaluated at one year using the United States Public Health Service (USPHS) criteria. Data were analyzed using Chi-square or Fisher's exact test.

RESULTS

All restorations had either Alpha or Bravo scores at one-year follow-up. In Group 1, all restorations scored Alpha, while one restoration each (3.6%) in Group 2 scored Bravo for fracture and marginal adaptation. All restorations in both groups scored Alpha for retention, secondary caries, and post-operative sensitivity. For anatomic form, all restorations in Group 1 scored Alpha, while three (10.7%) restorations in Group 2 had Bravo scores. For marginal discolouration, three restorations in both groups scored Bravo (11.5% and 10.7%, respectively). For surface roughness, one restoration (3.8%) in Group 1 and three restorations in Group 2 (10.7%) scored Bravo. The comparative results between the two groups for all the variables in the USPHS criteria were not statistically significantly different.

CONCLUSIONS

The performances of the nanofilled composite and alkasite were clinically acceptable and comparable. Alkasite can be an alternative material for the restoration of occlusal caries lesions in permanent molars of children.

CLINICAL TRIAL REGISTRATION

The clinical trial was registered at Clinical Trials Registry-India (CTRI Reg no: CTRI/2020/12/029830 Dated: 15/12/2020).

Resin-Based Composites for Direct and Indirect Restorations: Clinical Applications, Recent Advances, and Future Trends

Continuous advancements in resin-based composites can make selection of the appropriate system a daunting task for the clinician. This review aims to simplify this process and clarify some new or controversial topics. Various types of composites for direct and indirect applications are discussed, including microfilled and microhybrid composites, nanocomposites, single shade, bulk fill, fiber-reinforced, high temperature/high pressure processed, CAD/CAM, and three-dimensional printable composites. Recent material advancements that lead to improved seal and toughness, degradation resistance, antimicrobial and self-healing capabilities are presented. Future directions are highlighted, such as the development of "smart" materials that are able to interact with the host environment.

Randomized prospective clinical trial of class II restorations using flowable bulk-fill resin composites: 4-year follow-up

OBJECTIVES

This randomized, prospective, and split-mouth study aimed to evaluate flowable bulk-fill resin composites in class II restorations, comparing it with a conventional layering technique after 4-year follow-up.

MATERIALS AND METHODS

Fifty-three subjects received three class II restorations according to the restorative systems: conventional microhybrid composite resin (PA - Peak Universal + Amelogen Plus, Ultradent); flowable bulk-fill and nanoparticulate composite resins (ABF - Adper Single Bond 2 + Filtek Bulk Fill Flow + Filtek Z350XT, 3M/Espe); and flowable bulk-fill and microhybrid composite resins, (XST - XP Bond + SDR + TPH3, Dentsply). The clinical performance and interproximal contacts were evaluated. Statistical analyses were performed using the Kaplan-Meier, equality test of two proportions, Friedman, Wilcoxon, Kruskal-Wallis, Mann-Whitney, and Logistic regression analysis tests (alpha = 0.05).

RESULTS

In total, 106 restorations were evaluated at 4 years. Both systems with bulk-fill composites presented higher marginal discoloration than PA. About surface texture, ABF restorative system showed superior bravo scores being statistically similar to XST. Better performance for wear and surface staining was found for XST restorative system. All restorative systems resulted in the decreased interproximal contacts, occurring early for XST.

CONCLUSIONS

The restorative systems that used flowable bulk-fill resin composites showed satisfactory clinical performance compared with conventional resin composite after 4 years. All restorative systems had decreased proximal contact after 4 years.

CLINICAL RELEVANCE

Initial marginal discoloration was observed in more than 50% of class II restorations performed with restorative systems that used flowable bulk-fill resin composite. All restorative systems had decreased proximal contact strength over time.

Compliance of randomized controlled trials in posterior restorations with the CONSORT statement: a systematic review of methodology

OBJECTIVES

This study aims to investigate the compliance of randomized controlled trials (RCTs) in posterior restorations with the Consolidated Standards of Reporting Trials Statement (CONSORT) statement and to analyze the risk of bias (RoB) of these studies.

METHODS

A systematic search was performed in PubMed, Scopus, Web of Science, LILACS/BBO, and Cochrane Library. Only RCTs published in peer-reviewed journals were included. The compliance with the CONSORT was evaluated in a 0-2 scale where 0 = no description, 1 = poor description and 2 = adequate description. Descriptive analyses of the CONSORT mean score by journal, country, and RoB were performed. The RoB in RCTs was evaluated by using the Cochrane Collaboration's tool version 1.0.

RESULTS

A total of 15,476 studies were identified after duplicates removal. O only 202 meet the eligibility criteria, among which 31 were follow-up studies. Concerning the overall RoB, only 29 out of 171 were classified as low risk of bias. The overall mean CONSORT score was 19 ± 5.4 points, which means compliance of approximately 59%. Significant differences among countries, publication period, and RoB were observed (p < 0.001). The journal's impact factor was not correlated with the overall CONSORT score (p = 0.36).

CONCLUSIONS

The adherence of RCTs conducted in posterior restorations to the CONSORT Statement is still low. In addition, most studies were classified as at unclear risk of bias. These results call up an urgent need for improvement.

CLINICAL RELEVANCE

Most RCTs conducted in posterior teeth have poor reporting and are mainly classified as having an unclear risk of bias.

Three-year Randomized Prospective Clinical Trial of Class II Restorations Using Flowable Bulk-fill Resin Composites

OBJECTIVES

This randomized, prospective, and split-mouth study aimed to evaluate flowable bulk-fill resin composites in class II restorations and to compare with a conventional layering technique after a 3-year follow-up.

METHODS AND MATERIALS

Fifty-three subjects received three class II restorations according to the restorative systems: conventional microhybrid resin composite (PA, Peak Universal + Amelogen Plus, Ultradent), flowable bulk-fill and nanoparticulate resin composites (ABF, Adper Single Bond 2 + Filtek Bulk Fill Flow + Filtek Z350XT, 3M Oral Care), and flowable bulk-fill and microhybrid resin composites (XST, XP Bond + SDR + TPH3, Dentsply). The clinical performance and interproximal contacts were evaluated. Statistical analyses were performed using the equality test of two proportions, Logistic regression analysis, Friedman, Wilcoxon, Kruskal-Wallis, and Mann-Whitney tests (α=0.05).

RESULTS

Forty-seven patients were evaluated at 3 years. XST bulk-fill restorative system presented higher marginal discoloration than PA, and the opposite occurred for surface staining. All restorative systems resulted in decreased interproximal contacts, occurring early for XST.

CONCLUSIONS

Although the restorative system using incremental technique presented better performance for marginal discoloration, one of the restorative systems that used flowable bulk-fill resin composite (XST) showed the lowest surface staining. All restorative systems had decreased proximal contact over time.

Probing the hierarchy of evidence to identify the best strategy for placing class II dental composite restorations using current materials

OBJECTIVE

The objective of this review is to present a synopsis of the existing clinical and in vitro evidence regarding placement of direct class II restorations with dental composites of varying viscosities, focusing on the marginal integrity achievable.

OVERVIEW

The literature on class II composites placed with various techniques was searched through PubMed, Scopus, and the citations of identified articles, focusing on aspects related to adaptation and clinical performance. Studies comparing layering of conventional composite to layering with a flowable liner, including the "snow plow technique," use of warmed composite, flowable bulk-fill liners with a conventional composite capping layer, and bulk-fill restorative in a single or incremental fill (including placement with sonic energy and dual-curing) CONCLUSIONS: In vitro and clinical evidence does not support any one specific method or material type for achieving optimal performance when restoring class II cavity preparations with current dental composites.

CLINICAL SIGNIFICANCE

Although there are many available placement methods and types of composite materials on the market for use in class II restorations, the reasonable success presented in the clinical and laboratory literature for the various approaches suggests that the most important factor for achieving success is likely careful and proper placement and light-curing technique, independent of the approach.

Clinical Effectiveness of Bulk-Fill and Conventional Resin Composite Restorations: Systematic Review and Meta-Analysis

The objective of this systematic review and meta-analysis was to determine the clinical effectiveness of bulk-fill and conventional resin in composite restorations. A bibliographic search was carried out until May 2020, in the biomedical databases Pubmed/MEDLINE, EMBASE, Scopus, CENTRAL and Web of Science. The study selection criteria were: randomized clinical trials, in English, with no time limit, with a follow-up greater than or equal to 6 months and that reported the clinical effects (absence of fractures, absence of discoloration or marginal staining, adequate adaptation marginal, absence of post-operative sensitivity, absence of secondary caries, adequate color stability and translucency, proper surface texture, proper anatomical form, adequate tooth integrity without wear, adequate restoration integrity, proper occlusion, absence of inflammation and adequate point of contact) of restorations made with conventional and bulk resins. The risk of bias of the study was analyzed using the Cochrane Manual of Systematic Reviews of Interventions. Sixteen articles were eligible and included in the study. The results indicated that there is no difference between restorations with conventional and bulk resins for the type of restoration, type of tooth restored and restoration technique used. However, further properly designed clinical studies are required in order to reach a better conclusion.

Polymerization Shrinkage and Degree of Conversion of New Zirconia-Reinforced Rice Husk Nanohybrid Composite

Objectives  This study aimed to compare the polymerization shrinkage and degree of conversion of new zirconia-reinforced rice husk nanohybrid composite with commercialized microhybrid and nanofilled composites.

Materials and Methods  Overall, 180 samples were used for polymerization shrinkage (buoyancy and optical methods) and degree of conversion tests in which they were divided into Group 1, nanofilled composite (Filtek-Z350- XT; 3M ESPE, St Paul, MN 55144-1000, USA), Group 2, microhybrid composite (Zmack-Comp), and Group 3, nanohybrid composite (Zr-Hybrid). Polymerization shrinkage test was performed using buoyancy and optical methods. For buoyancy method, samples were weighed in air and water to calculate the shrinkage value, whereas, for optical method, images of nonpolymerized samples were captured under a digital microscope and recaptured again after light-cured to calculate the percentage of shrinkage. Degree of conversion was tested using Fourier-transform infrared spectroscopy spectrometer.

Statistical Analysis  Data were analyzed using one-way analysis of variance complemented by post hoc Dunnett’s T3 test for polymerization shrinkage and Tukey’s honestly significant difference test for degree of conversion. Level of significance was set at p < 0.05.

Results  Group 3 demonstrated similar polymerization shrinkage with Group 1, but lower shrinkage ( p < 0.05) than Group 2 based on buoyancy method. However, optical method ( p < 0.05) showed that Group 3 had the lowest shrinkage, followed by Group 1 and lastly Group 2. Besides, Group 3 showed a significantly higher degree of conversion ( p < 0.05) than Group 1 and comparable conversion value with Group 2.

Conclusions  Zirconia-reinforced rice husk nanohybrid composite showed excellent shrinkage and conversion values, hence can be considered as an alternative to commercially available composite resins.

Clinical performance and chemical-physical properties of bulk fill composites resin -a systematic review and meta-analysis

OBJECTIVES

The objective of this study was to perform a meta-analysis of clinical and laboratory studies to compare the performance of bulk-fill and conventional composite resins in terms of polymerization shrinkage, polymerization stress, cusp deflection, marginal quality, degree of conversion, microhardness, flexural strength, fracture strength and clinical performance.

DATA

One hundred three articles were included in this study, and the Peto method was used to compare the bulk-fill and conventional composites using the RevMan software.

SOURCES

Searches were performed in the PubMed and Scopus databases.

STUDY SELECTION

Laboratory studies and randomized clinical trials comparing one of the previous detailed outcomes between bulk-fill and control composites were included.

CONCLUSIONS

The bulk-fill composite resins showed less shrinkage, polymerization stress, cusp deflection and microhardness than conventional composites, while both materials presented a similar marginal quality, flexural strength and fracture strength. Also, bulk-fill materials with regular viscosity showed similar shrinkage. The conversion of bulk-fill materials with flowable consistency were similar to conventional composite resins with a thickness of up to 2mm and greater than conventional composites with a thickness greater than 2mm. Despite these in vitro differences, the clinical performance of bulk-fill and conventional composite resins was similar in randomized clinical trials, with one to ten years of follow up. In conclusion, the bulk-fill materials show better or similar performance to the conventional materials in clinical trials and laboratory studies in terms of volumetric shrinkage, polymerization stress, cusps deflection and marginal quality, with the only exception being the lower level of microhardness observed for bulk-fill composites with thickness up to 2mm.