Effects of Ions-Releasing Restorative Materials on the Dentine Bonding Longevity of Modern Universal Adhesives after Load-Cycle and Prolonged Artificial Saliva Aging

Clinical Effectiveness of Ion-Releasing Restorations versus Composite Restorations in Dental Restorations: Systematic Review and Meta-Analysis

BACKGROUND

To compare the clinical effectiveness of ion-releasing restorations (IRR) vs. composite resin (CR) in dental restorations.

METHODS

A systematic search was carried out from articles published until January 2024, in the biomedical databases: PubMed, Cochrane Library, Scielo, Scopus, Web of Science and Google Scholar. Randomized clinical trials were included, with a follow-up time greater than or equal to 1 year, without time and language limits and which reported the clinical effect of IRR compared to CR in dental restorations. The RoB 2.0 tool was used to assess the risk of bias of the included studies and the GRADEPro GDT tool was used to assess the quality of evidence and the strength of recommendation of the results.

RESULTS

The search yielded a total of 1109 articles. After excluding those that did not meet the selection criteria, 29 articles remained for the quantitative synthesis. The analysis found no statistically significant difference when comparing the dental restorations with IRRs or CRs.

CONCLUSION

The literature reviewed suggests that there are no differences between the IRRs and CRs in dental restorations.

3-year randomized clinical trial to evaluate the performance of posterior composite restorations lined with ion-releasing materials

To evaluate the impact of using ion-releasing liners on the 3-year clinical performance of posterior resin composite restorations after selective caries excavation with polymer burs. 20 patients were enrolled in this trial. Each patient had two deep carious lesions, one on each side of the mouth. After selective caries removal using polymer bur (PolyBur P1, Komet, Brasseler GmbH Co. KG, Lemgo, Germany), cavities were lined with bioactive ionic resin composite (Activa Bioactive Base/Liner, Pulpdent, Watertown, MA, USA) or resin-modified glass ionomer liner (Riva Light Cure, SDI, Bayswater, Victoria, Australia). All cavities were then restored with nanofilled resin composite (Filtek Z350XT, 3M Oral Care, St. Paul, MN, USA). All the tested materials were placed according to the manufacturers' instructions. Clinical evaluation was accomplished using World Dental Federation (FDI) criteria at baseline and after 6 months, 1, 2, and 3 years. Data were analyzed using Mann-whitney U and Friedman tests (p < 0.05). The success rates were 100% for all resin composite restorations either lined with ion-releasing resin composite or resin-modified glass ionomer liner. Mann-whitney U test revealed that there were no statistically significant differences between both ion-releasing lining material groups for all criteria during the follow-up periods (p > 0.05). Resin composite restorations showed acceptable clinical performance over 3 years either lined with bioactive ionic or resin-modified glass ionomer liners after selective caries excavation preserving pulp vitality. After the 3-year follow-up period, Activa Bioactive and Riva Light Cure liners were clinically effective and they exhibited with the overlying composite restorations successful clinical performance.Trial registration number: NCT05470959. Date of registration: 22/7/2022. Retrospectively registered.

Bonding performance and interfacial adaptation of modern bulk-fill restorative composites after aging in artificial saliva: an in vitro study

OBJECTIVES

This study aimed at comparing the microtensile bond strength (MTBS) and interfacial adaptation of a modern self-curing and a light-curing restorative bulk-fill composite to a conventional composite applied with the layering technique.

METHODS

Forty-eight occlusal cavities were divided in three main groups (16/group) based on tested materials: (i) STELA, bulk-fill self-curing restorative (STELA, SDI Ltd.); (ii) 3 M-BULK, bulk-fill composite (Filtek One Bulk-Fill, 3 M Oral Care); and (iii) 3 M-CTR, a conventional composite (Filtek Supreme XTE, 3 M Oral Care). These were used in combination with their adhesives in self-etch (SE) or etch-and-rinse (ER) mode. Specimens stored in artificial saliva (24 h or 12 months) were evaluated for MTBS and fractography. The interfacial analysis was performed through confocal microscopy. ANOVA and Fisher's LSD post hoc tests were performed with a level of significance of 5%.

RESULTS

All the tested materials applied in ER mode presented (24 h) greater bond strength than in SE mode. Although all materials showed a significant drop in the bond strength after prolonged storage, STELA showed the highest bonding performance and interfaces with few gaps. 3 M-BULK had the lowest bond strength and an interface with several voids and gaps.

CONCLUSIONS

All materials were affected by interface degradation and bonding reduction over prolonged aging. However, their use in combination with adhesives applied in ER mode may offer greater immediate bonding performance.

CLINICAL RELEVANCE

The use of restorative light-curing bulk-fill composites may generate gaps at the bonding interface and voids. STELA may represent a suitable alternative to avoid such issues.

Effect of different storage media on elemental analysis and microhardness of cervical cavity margins restored with a bioactive material

Objectives

This study aimed to investigate the elemental analysis and microhardness of a bioactive material (Activa) and marginal tooth structure after storage in different media.

Materials and Methods

Fifteen teeth received cervical restorations with occlusal enamel and gingival dentin margins using the tested material bonded with a universal adhesive, 5 of them on the 4 axial surfaces and the other 10 on only the 2 proximal surfaces. The first 5 teeth were sectioned into 4 restorations each, then stored in 4 different media; deionized water, Dulbecco's phosphate buffered saline (DPBS), Tris buffer, and saliva. The storage period for deionized water was 24 hours while it was 3 months for the other media. Each part was analyzed by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analysis for different substrates/distances and the wt% of calcium, phosphorus, silica, and fluoride were calculated. The other 10 teeth were sectioned across the restoration, stored in either Tris buffer or saliva for 24 hours or 3 months, and were evaluated for microhardness of different substrates/areas. Data were analyzed using analysis of variance and Tukey's post hoc test.

Results

Enamel and dentin interfaces in the DPBS group exhibited a significant increase in calcium and phosphorus wt%. Both silica and fluoride significantly increased in tooth structure up to a distance of 75 μm in the 3-month-media groups than the immediate group. Storage media did not affect the microhardness values.

Conclusions

SEM-EDS analysis suggests an ion movement between Activa and tooth structure through a universal adhesive while stored in DPBS.

Microshear Bond Strength of Bioactive Materials to Dentin and Resin Composite

OBJECTIVES

 The aim of this study was to comparatively evaluate microshear bond strength (μSBS) of bioactive ionic resin composite and resin-modified glass ionomer liner (RMGI) to dentin and resin composite.

MATERIALS AND METHODS

 The enamel of 11 posterior molar teeth was removed to expose dentin and then placed in acrylic blocks. Each specimen received three microcylindrical Tygon tubes filled with bioactive ionic resin composite (Activa Bioactive base/liner (PULPDENT: , MA, USA)), RMGI (Riva light cure SDI LTD, Bayswater, Australia), and resin composite (Filtek Z350xt, MN, USA). Composite discs (n = 11) were fabricated from nanofilled resin composite (Filtek Z350xt) and then fixed in acrylic blocks. Each specimen received two microcylindrical Tygon tubes filled with Activa Bioactive base/liner and Riva RMGI. All specimens were mounted individually to universal testing machine for μSBS test. Failure modes were analyzed using stereomicroscope and scanning electron microscope.

RESULTS

 Filtek Z350xt nanofilled resin composite showed the highest μSBS values. No statistical significant difference was found between Activa Bioactive and Riva RMGI (p > 0.05).

CONCLUSION

 Bioactive ionic resin composite liner exhibited similar bond strength as RMGI to dentin and resin composite.

Present status and future directions: The restoration of root filled teeth

This narrative review will focus on a number of contemporary considerations relating to the restoration of root filled teeth and future directions for research. Clinicians are now more than ever, aware of the interdependence of the endodontic and restorative aspects of managing root filled teeth, and how these aspects of treatment are fundamental to obtaining the best long-term survival. To obtain the optimal outcomes for patients, clinicians carrying out endodontic treatment should have a vested interest in the restorative phase of the treatment process, as well as an appreciation for the structural and biomechanical effects of endodontic-restorative procedures on restoration and tooth longevity. Furthermore, the currently available research, largely lacks appreciation of occlusal factors in the longevity of root filled teeth, despite surrogate outcomes demonstrating the considerable influence this variable has. Controversies regarding the clinical relevance of minimally invasive endodontic and restorative concepts are largely unanswered with respect to clinical data, and it is therefore, all too easy to dismiss these ideas due to the lack of scientific evidence. However, conceptually, minimally invasive endodontic-restorative philosophies appear to be valid, and therefore, in the pursuit of improved clinical outcomes, it is important that the efficacies of these treatment protocols are determined. Alongside an increased awareness of the preservation of tooth structure, developments in adhesive bonding, ceramic materials and the inevitable integration of digital dentistry, there is also a need to evaluate the efficacy of new treatment philosophies and techniques with well-designed prospective clinical studies.

An in vitro micro-CT assessment of bioactive restorative materials interfacial adaptation to dentin

BACKGROUND

The background of this study was to improve the longevity of a restoration and optimal adaptation of restorative material to the prepared cavity walls is crucial. The study aimed to evaluate the interfacial adaptation of Activa, Micron, and Predicta bulk bioactive restorative materials to coronal dentin using micro-computed tomography (CT) analysis.

MATERIALS AND METHODS

In this in vitro micro-CT assessment study, Class II mesio- and disto-occlusal cavities were prepared on 60 extracted human mandibular molar teeth. After etching and bonding procedures, all the mesial cavities (n = 60) were restored with Tetric N-Ceram and the disto-occlusal cavities with Activa or Micron or Predicta bioactive (n = 20 each) restoratives. Interfacial gap percentages were evaluated under micro-CT before (baseline) and after thermo-mechanical load cycling (TMC). Acquired data were analyzed statistically using one-way analysis of variance, Paired t-test, and Tukey's multiple post hoc procedures, at P < 0.05 level of significance.

RESULTS

The interfacial gap percentages were lowest for Predicta bioactive and highest for the Micron group (P < 0.05). The number of gaps increased significantly after TMC in all the groups (P < 0.05). The adaptation of tested materials was inferior to axial wall and pulpal floor, whereas considerably better adaptation was observed on buccal and lingual walls.

CONCLUSION

Predicta bioactive followed by Activa bioactive has shown superior interfacial adaptation, whereas Micron bioactive demonstrated maximum microgaps compared to nanohybrid composite. Artificial aging with TMC has a negative influence on the internal adaptation of all tested materials.

Bonding performance and ultramorphology of the resin-dentine interface of contemporary universal adhesives

OBJECTIVES

This study aimed at evaluating the microtensile bond strength (μTBS) and the resin-dentine ultramorphology (24 h and 10 months ageing) of contemporary universal adhesives applied in self-etch (SE) or etch-and-rinse (ER) mode.

MATERIALS AND METHODS

Sixty-four sound human molars were collected and randomly allocated in 4 main experimental groups (n = 16) according to the adhesive system employed and subsequently divided into two subgroups depending on their application mode SE or ER (n = 8): ZipBond X (ZBX-SE; ZBX-ER), Prime and Bond Active (PBA-SE; PBA-ER), Clearfil Universal Bond Quick (CBQ-SE; CBQ-ER) or Scotchbond Universal (SCH-SE; SCH-ER). The specimens were cut into sticks with a cross-sectional area of approximately 0.9 mm² and subjected to μTBS testing at 24 h or after 10 months of ageing in artificial saliva (AS). Five representative fractured specimens from each group were analysed using field-emission scanning electron microscopy (FE-SEM). Resin-dentine slabs (Ø 0.9mm²) from each experimental group were immersed in Rhodamine B and subsequently analysed using confocal microscopy analysis (CLSM). The μTBS results were analysed using a two-way ANOVA and Newman-Keuls multiple-comparison test (α = 0.05).

RESULTS

ZBX, PBA and SCH exhibited greater μTBS values than CQB at 24 h in both SE and ER modes (p < 0.05). CQB showed a significant decrease in μTBS values after ageing both when used in SE and ER mode (p < 0.05). ZBX-ER exhibited no significant differences in the μTBS test after ageing (p > 0.05), while a significant drop in μTBS was seen in SCH-ER and APB-ER after 10-month ageing (p < 0.05). Clear signs of degradation were evident in the resin-dentine interface created with CQB regardless of the application mode or the ageing time. In APB-ER and SCH-ER groups, such signs of degradation were evident after ageing in AS. ZBX showed slight dye infiltration both when used in ER and SE mode.

CONCLUSIONS

The long-term bonding performance of modern universal adhesives is usually influenced by the adhesive strategy employed; self-etching application should be prioritised during dentine bonding. Moreover, the use of shortened bonding protocols may compromise the quality of the resin-dentine interface and the bonding performance of most modern universal adhesives.

CLINICAL RELEVANCE

The use of etch-and-rinse bonding procedures, as well as "shortened" application protocols should be eluded when using modern universal adhesives in dentine. However, new generation universal adhesives based on innovative chemical formulations may probably allow clinicians to achieve long-term bonding performance with such simplified system also when employed in ER mode.

Commercially Available Ion-Releasing Dental Materials and Cavitated Carious Lesions: Clinical Treatment Options

The contemporary approach for operative caries management emphasizes personalized interventions for each patient, dependent upon the individual's caries susceptibility/risk, the stage of the carious lesion and its activity. The clinician's challenge is to optimize the extent of cavity preparation and the choice of dental restorative biomaterials, appreciating the benefits offered by ion-releasing restorative materials. There is a growing application of bioactive/bio-interactive materials in minimally invasive operative dentistry, as they may help with tissue recovery by ion release. In case of moderate or extensive occlusal cavitation, the clinical criteria include the individual caries susceptibility and carious lesion activity. In high caries risk cases, ion-releasing biomaterials (IRB) can be used, as well as for active carious lesions. In proximal lesions, the clinical criteria include the individual caries susceptibility, the lesion activity and presence of cavities with little or no enamel at the gingival margin. This article aims to discuss the restorative ion-releasing options, according to different clinical situations, and the caries susceptibility to manage cavitated carious lesions in permanent adult teeth.

The Bond Strength and Antibacterial Activity of the Universal Dentin Bonding System: A Systematic Review and Meta-Analysis

Streptococcus mutans (S. mutans) is a group of viridans mostly located in oral flora among the wide and biodiverse biofilm. It plays a significant role not only in caries formation but also triggering intracerebral haemorrhage. The durable and stable bond interface, besides bacteria elimination, is one of the crucial factors influencing the resin composite restoration performance. This study aimed to evaluate universal adhesives (UAs) with regard to in vitro bond strength to dentin, and the inhibition of the S. mutans growth and compare them with UAs modified with antimicrobial agents through a systematic review and meta-analysis. Two reviewers performed a literature search up to April 2021 in 5 electronic databases: PubMed MedLine, Scielo, ISI Web of Science, Scopus, and EMBASE. Only in vitro studies reporting the effect of modifying UAs with antimicrobial agents on the bond strength to dentin and/or on the inhibition of the S. mutans were included. Analyses were carried out using Review Manager Software version 5.3.5 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark). The methodological quality of each in vitro study was evaluated following the parameters of a previous systematic review. A total of 1716 potentially relevant publications were recognized. After reviewing the title and abstract, 16 studies remained in the systematic review. From these, a total of 3 studies were included in the meta-analysis. Since data from the studies included in the antimicrobial outcome included zero values, they could not be meta-analysed. Including 0 values in the analysis will lead to several biases in the analysis, so these data were discarded. The antibacterial effect against S. mutans of UAs modified with antimicrobial agents was higher than the non-modified adhesive systems. Within the limitations of the present study, the bond strength of UAs to dentin could be improved by using antimicrobial agents. The UAs modified with antibacterial agents showed a decrease in the viability of S. mutans biofilm, among the adhesives tested. However, there are not enough valid data on antibacterial properties of modified UAs; therefore, more well-designed research on these materials is needed.

Antibacterial and Bonding Properties of Universal Adhesive Dental Polymers Doped with Pyrogallol

This study investigated the antibacterial activity, bond strength to dentin (SBS), and ultra-morphology of the polymer-dentin interface of experimental adhesive systems doped with pyrogallol (PY), which is a ubiquitous phenolic moiety that is present in flavonoids and polyphenols. A universal adhesive containing 4-META and 10-MDP was used in this study. PY behaves as an antioxidant and anti-cancerogenic agent and it was incorporated into the adhesive at different concentrations (0.5 and 1 wt.%). The antibacterial activity and SBS were analyzed and the results were statistically analyzed. The ultra-morphology of the polymer-dentin interface was assessed using scanning electron microscopy (SEM). At 24 h, a lower antibacterial activity was observed for the control adhesive compared to those with 0.5% and 1% PY. No difference was seen in SBS between the three groups at 24 h. After 6 months, the SBS of the 0.5% PY adhesive was significantly lower than the other tested adhesives. The specimens created with 1% PY adhesive presented a higher bond strength at six months compared with that found at 24 h. No morphological differences were found at the polymer-dentin interfaces of the tested adhesives. Pyrogallol may be incorporated into modern universal adhesive systems to preserve the polymer-dentin bonding interface and confer a certain degree of antibacterial activity.

Biophysical and Fluoride Release Properties of a Resin Modified Glass Ionomer Cement Enriched with Bioactive Glasses

The aim of this study was to evaluate the bond strength, microleakage, cytotoxicity, cell migration and fluoride ion release over time from a resin-modified glass-ionomer cement (RMGIC) enriched with bioactive glasses (BAGs) and a nanohybrid restorative polymer resin agent used as adhesion material in the cemented brackets. One hundred and twenty bovine lower incisors were divided into three groups: (Transbond Plus Self Etching Primer (TSEP)/Transbond XT (TXT), TSEP/ACTIVA, orthophosphoric acid gel/ACTIVA) and brackets were bonded. A bond strength test and microleakage test were applied. A fluoride release test was applied after 60 days for the TXT and ACTIVA group. To evaluate cytotoxicity and cell migration, a cell viability and scratch migration assay were done for each group. p values < 0.05 were considered significant. Regarding bond strength and microleakage test, no significant differences were found between TSEP/TXT and TSEP/ACTIVA. At 6.4 pH, ACTIVA showed a higher degree of fluoride ion release, which increased with acid pH (3.5), with a maximum fluoride secretion at 30 days. MTT assay revealed that TXT reduces the viability of gingival cells with significant differences (p < 0.001) compared to the untreated cells (control group). ACTIVA provides optimal adhesive and microfiltration properties, releases substantial amounts of fluoride ions in both acid and neutral media, and its biocompatibility is greater than that of traditional composite resin adhesive systems.

Does Adhesive Layer Thickness and Tag Length Influence Short/Long-Term Bond Strength of Universal Adhesive Systems? An In-Vitro Study

(1) Background: This study investigated the effect of the adhesive layer thickness and the length of resin tags on dentin bond strength of five universal adhesives applied in self-etch mode. (2) Methods: One hundred and fifty extracted human third molars were used. Five different universal adhesives were applied in self-etch mode on the dentin surface. Half of the specimens were subjected to an aging procedure for six months. A shear bond strength (SBS) test was performed and the results were statistically analyzed with a t-test and one-way ANOVA test. Scanning electron microscopy (SEM) was executed to measure the adhesive layer thickness and tag depth. (3) Results: No statistical differences were found between the five adhesive systems after a 24 h storage period, regardless of layer thickness and tag depth (p < 0.05). After 6 months of aging in water at 37 °C, Iperbond Max and Scotchbond Universal preserved the bond strength over time (p < 0.05), whilst the SBS of Iperbond Ultra, FuturaBond M+, and Ibond Universal decreased significantly after the aging period. No relation was observed between the adhesive thickness or tags’ length on SBS. (4) Conclusions: Within the limitation of this study, the stability over time of the bond strength of universal adhesives depends on their compositions regardless of the adhesive layer thickness and/or tags’ length.

Flexural strength and microhardness of bulk-fill restorative materials

BACKGROUND

Bulk-fill materials can facilitate the restorative procedure mainly for deep and wide posterior cavities. The purpose of this study was to evaluate flexural strength (biaxial flexural strength [BFS]) and microhardness (Knoop microhardness [KHN]) at different depths of bulk-fill materials.

METHODS

Five bulk-fill materials were tested: two light-curable composite resins, one dual-cure composite, one bioactive restorative, and a high-viscosity glass ionomer. A conventional composite was used as control. BFS and KHN were tested at different depths. Data was analyzed by two- and one-way ANOVAs, respectively and Tukey's post-hoc (α=0.05).

RESULTS

The high-viscosity glass ionomer material presented the lowest BFS at all depths. KHN for the two light-curable and the dual-cure bulk-fill resin composites was reduced following an increase in restoration depth, while the conventional composite, the bioactive material, and the high-viscosity glass ionomer were not affected.

CONCLUSION

There are differences in the properties of the tested materials at 4 mm depth, showing that the studied properties of some materials vary according to the cavity depth, although the results are material dependent.

CLINICAL SIGNIFICANCE

Mechanical properties of light-cured, bulk-fill materials may be affected by inadequate polymerization. Clinicians should consider complementary strategies to achieve adequate polymerization at high-increment depths.

Contemporary restorative ion-releasing materials: current status, interfacial properties and operative approaches

Minimally invasive (MI) concepts in restorative dentistry in the year 2020 request from the practitioner not only a scientifically supported rationale for carious tissue removal/excavation and defect-oriented, biological cavity preparation, but also a deep understanding of how to ensure a biomechanically stable and durable restoration in different clinical situations by applying different restorative options. Bio-interactive materials play an increasingly relevant role, as they not only replace diseased or lost tissue, but also optimise tissue mineral recovery (among other properties) when used in restorative and preventive dentistry. Indeed, this is of certain interest in MI restorative dentistry, especially in those cases where gap formation jeopardises the integrity of the margins along resin composite restorations, causing penetration of bacteria and eventually promoting the formation of secondary caries. Recently, the interest in whether ion-releasing materials may reduce such biofilm penetration into margin gaps and reduce such a risk for development and propagation of secondary caries is growing significantly among clinicians and scientists. The aim of this article was to explore mechanisms involved in the process that allow mineral deposition at the interface between such materials and dentine, and to describe how conventional 'bioactive' restorative materials currently available on the market may benefit treatments in MI dentistry.

Pure Ormocer vs Methacrylate Composites on Posterior Teeth: A Double-blinded Randomized Clinical Trial

CLINICAL RELEVANCE

The clinical behavior of pure ormocer composite is reliable when used in class II restorations after 24 months of evaluation.

SUMMARY

In vitro wear of dual-cured bulkfill composites and flowable bulkfill composites

OBJECTIVES

The objective of this study is to test the wear of dual-cured bulkfill and flowable bulkfill composites.

MATERIALS AND METHODS

Six dual-cured bulkfill composites, Cention, Cention-Exp, Activa, Fill-up, Hyperfil Injectafill, and two flowable bulkfill composites Tetric Evoflow BulkFill and G-aenial Universal Flo were tested in this study (n = 8). Each composite was applied into an aluminum sample holder and cured with a Valo Grand (1230 mW/cm² ) or self-cured according to manufacturer's recommendations, and stored in water for 3 weeks. The samples were subjected to 120 000 load cycles of 49 N (CS-4) against spherical steatite antagonists and simultaneously subjected to 4440 thermocycles (5°C-55°C). At intervals between load cycles, polyvinyl siloxane impressions were taken and scanned with a True Definition Laser Scanner. The volumetric wear was calculated using image software (Geomagic). Microscopic images of selected wear facets and their corresponding worn antagonists were obtained using SEM. All data were analyzed using analysis of variance (ANOVA) and Tukey post hoc test for multiple comparison (α = .05; β = .2).

RESULTS

The load cycles volumetric wear-increase was linear. Two-way ANOVA showed significant main effects (material and light-cured) and significant interactions. Self-cured materials (mean = 0.38 mm³ ) showed more wear than light-cured materials (mean = 0.35mm³ ).

CONCLUSIONS

The bioactive materials except Activa light-cured showed significantly more wear than the flowable composites.

CLINICAL SIGNIFICANCE

This study demonstrated that most of the dual-cured composites, if light-cured, showed the same wear as the flowable composites used as control. Therefore, to obtain adequate wear resistance the dual-cured composites should be routinely light-cured.

Effect of Casein Phosphopeptide-Amorphous Calcium Phosphate on Fracture Resistance of Reattached Tooth Fragments Using Conventional and Self-Adhesive Bioactive Flowable Composite

Objectives  The present study aimed to investigate the effect of casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) complex and the type of flowable composite (conventional or self-adhesive bioactive) on the fracture resistance of fractured incisors restored through reattachment technique.

Materials and Methods  In this experimental in vitro study, 60 extracted bovine central mandibular incisors were randomly divided into six groups ( n = 10) according to the reattachment technique. Their incisal edges were cut off to represent an enamel–dentin fracture. The fragment edges were reattached as follows: Group 1—selective etching and bonding followed by conventional flowable composite; Group 2—selective etching and bonding followed by bioactive flowable composite; Group 3 was like Group 2 but without applying bonding; Groups 4, 5, and 6 were similar to Groups 1, 2, and 3, respectively, but both tooth fragments were pretreated with CPP-ACP-containing paste for 3 minutes. Fracture resistance was assessed by a universal testing machine.

Statistical Analysis  Data were analyzed by SPSS—Statistical Package for the Social Sciences—software using one-way analysis of variance and Tukey post-hoc tests (α= 0.05).

Results  The highest and lowest fracture resistance was recorded in Groups 5 (15.96 MPa) and Group 6 (1.95 MPa), respectively, being significantly different from the other groups. The mean fracture resistance of Groups 3 and 6 was significantly lower than the other groups ( p < 0.05). However, Groups 1, 2, and 4 showed no difference in fracture resistance.

Conclusion  Bioactive composite was not superior to conventional composite for fragment reattachment, but using it in self-adhesive mode reduced the fracture strength significantly. Yet, pretreatment with CPP-ACP, followed by application of adhesive, improved the fracture resistance of bioactive composite.

In Vitro Evaluation of the Biological Effects of ACTIVA Kids BioACTIVE Restorative, Ionolux, and Riva Light Cure on Human Dental Pulp Stem Cells

This study aimed to analyze the biological effects of three new bioactive materials on cell survival, migration, morphology, and attachment in vitro. ACTIVA Kids BioACTIVE Restorative (Pulpdent, Watertown, MA, USA) (Activa), Ionolux (Voco, Cuxhaven, Germany), and Riva Light Cure UV (SDI, Bayswater, Australia) (Riva) were handled and conditioned with a serum-free culture medium. Stem cells from human dental pulp (hDPSCs) were exposed to material extracts, and metabolic activity, cell migration, and cell morphology were evaluated. Cell adhesion to the different materials was analyzed by scanning electron microscopy (SEM). The chemical composition of the materials was evaluated by energy-dispersive X-ray (EDX). One-way analysis of variance followed by a Tukey test was performed (p < 0.05). Ionolux promoted a drastic reduction in metabolic activity and wound closure compared to the control (p < 0.05), whereas Activa induced adequate metabolic activity and cell migration. Moreover, SEM and immunofluorescence analysis showed abundant cells exposed to Activa. The materials showed different surface morphologies, and EDX spectra exhibited different peaks of C, O, Si, S, Ca, and F ions in glass ionomer cements. The results showed that Activa induced cell migration, cell attachment, and cell viability to a greater extent than Riva and Ionolux.