Clinical performance of two ion-releasing bulk-fill composites in class I and class II restorations: A two-year evaluation.

OBJECTIVES: This randomized clinical trial evaluated and compared the 2-year clinical performance of two ion-releasing bulk-fill composites (Cention N and Surefil One) with that of a conventional bulk-fill resin composite (Powerfil) in Class I and II cavities. METHODS: Thirty-two patients, each with 3 Class I and/or Class II cavities under occlusion, were enrolled in this trial. A total of 96 restorations were placed, 32 for each material, as follows: a self-adhesive composite; Surefil-one, alkasite; Cention N, and a bulk-fill resin composite; Powerfil. The restorations were placed by a single operator. Clinical evaluation was performed at baseline (1-week), 6-months, 1-year, and 2-years by two independent examiners using the FDI criteria. Intergroup and intragroup comparisons were analyzed using the Kruskal-Wallis and Friedman Tests. Multiple comparisons between groups were analyzed using the Mann-Whitney and Wilcoxon-rank tests. The level of significance was set at α = 0.05. RESULTS: Twenty-seven patients with a total of 81 restorations were evaluated at the end of the 2-years with 84.35% recall rates. Clinical success rates were 100%, 100%, and 96.3% for Powerfil, Surefil-one, and Cention N, respectively. Cention N showed a statistically significant (p < 0.05) decreased marginal integrity in comparison with resin composite at the 2-year evaluation. No recurrent decay was detected in any restoration. CONCLUSIONS: Both ion-releasing bulk-fill composites provided acceptable clinical performance similar to bulk-fill composite in Class I and II restorations over a 2-year period. CLINICAL RELEVANCE: The results of this trial suggests that there is a promising evidence supporting the use of ion-releasing composites.

Effect of various surface coating methods on surface roughness, micromorphological analysis and fluoride release from contemporary glass ionomer restorations.

OBJECTIVE: To evaluate the effect of various surface coating methods on surface roughness, micromorphological analysis and fluoride release from contemporary resin-modified and conventional glass ionomer restorations. MATERIALS & METHODS: A total of 72 permanent human molars were used in this study. The teeth were randomly assigned into 2 groups according to type of restorative materials used; resin modified glass ionomer cement and conventional glass ionomer (SDI Limited. Bayswater Victoria, Australia). Each group was subdivided into 3 subgroups according to the application of coat material; Sub-group1: without application of coat; Sub-group2: manufacturer recommended coat was applied and sub-group3: customized (vaseline) coat was applied. Each group was then subdivided into two divisions according to the time of testing; immediate (after 24 h) and delayed (after 6 months of storage). Three specimens from each sub-group were selected for surface roughness test (AFM) and another 3 specimens for the micromorphological analysis using scanning electron microscope (SEM). For the fluoride release test, a total of 60 cylindrical discs were used (n = 60). The discs were randomly split into 2 groups according to type of restorative materials used (n = 30); resin modified glass ionomer cement and conventional glass ionomer. Each group was subdivided into 3 subgroups (n = 10) according to the application of the coat material; Sub-group1: without application of coat; Sub-group2: with the manufacturer recommended coat and sub-group3: with application of customized (vaseline) coat. Data for each test was then collected, tabulated, were collected, tabulated, and tested for the normality with Shapiro-Wilk test. Based on the outcome of normality test, the significant effects of variables were assessed using appropriate statistical analysis testing methods. RESULTS: Regarding the data obtained from surface roughness test, Shapiro-Wilk test showed normal distribution pattern of all values (p > 0.05). Accordingly, Two-way ANOVA outcome showed that the 'type of restoration' or 'test time' had statistically significant effect on the AFM test (p < 0.05). Regarding Fluoride specific ion electrode test 2-way ANOVA followed by Least Significant Difference (LSD) Post-hoc test revealed significant difference among the groups (p < 0.05). It showed that SDI GIC group after 14 days of measurement had the highest mean of fluoride release (36.38 ± 3.16 PPM) and SDI RMGIC after 30 days of measurement had the second highest mean of fluoride release (43.28 ± 1.89 PPM). Finally, regarding the micromorphological analysis using SEM, a slight difference was observed between the studied groups. CONCLUSIONS: Based on the results of this study, various coatings enhance surface roughness in the initial 24 h of restoration insertion. Different coat types seems that have no influence on fluoride release and the micromorphological features of the restoration/dentin interface.

Microhardness and elemental analysis of ion-releasing restoration/ dentin interface following enzymatic chemomechanical caries excavation.

BACKGROUND: This study was conducted to compare chemical, elemental and surface properties of sound and carious dentin after application of two restorative materials resin-modified glassionomer claimed to be bioactive and glass hybrid restorative material after enzymatic chemomechanical caries removal (CMCR) agent. METHODS: Forty carious and twenty non-carious human permanent molars were used. Molars were randomly distributed into three main groups: Group 1 (negative control) - sound molars, Group 2 (positive control) - molars were left without caries removal and Group 3 (Test Group) caries excavated with enzymatic based CMCR agent. After caries excavation and restoration application, all specimens were prepared Vickers microhardness test (VHN), for elemental analysis using Energy Dispersive Xray (EDX) mapping and finally chemical analysis using Micro-Raman microscopy. RESULTS: Vickers microhardness values of dentin with the claimed bioactive GIC specimens was statistically higher than with glass hybrid GIC specimens. EDX analysis at the junction estimated: Calcium and Phosphorus of the glass hybrid GIC showed insignificantly higher mean valued than that of the bioactive GIC. Silica and Aluminum mean values at the junction were significantly higher with bioactive GIC specimens than glass hybrid GIC specimen. Micro-raman spectroscopy revealed that bioactive GIC specimens showed higher frequencies of v 1 PO 4, which indicated high level of remineralization. CONCLUSIONS: It was concluded that ion-releasing bioactive resin-based restorative material had increased the microhardness and remineralization rate of carries affected and sound dentin. In addition, enzymatic caries excavation with papain-based CMCR agent has no adverse effect on dentin substrate.

In vitro elemental and micromorphological analysis of the resin-dentin interface of bioactive and bulk-fill composites.

PURPOSE: To evaluate the bonding interface and the remineralization potential of a bioactive restorative material on demineralized dentin compared to a conventional bulk-fill resin composite restoration. METHODS: Twelve caries-free human molars were used in this study. Specimens were randomly divided into two groups according to the type of restorative material used (n=12); an injectable resin-modified glass-ionomer restorative [Activa BioActive-Restorative (ABR) ] and a bulk-fill composite [3M Filtek One Bulk Fill Restorative, (BFC) ]. Each restored specimen was sectioned in two semi-equal halves along the long axis of the teeth perpendicular to the resin dentin interface with a water-cooled diamond disk at low speed. The restoration-dentin interfaces were scanned under SEM to observe micromorphological analysis; then an elemental analysis of the interface was performed using an energy dispersive X-ray (EDX) spectroscopy. RESULTS: Quantitative data were described using median (minimum and maximum) after testing normality using the Shapiro-Wilk test. Mann-Whitney U test was used to compare the BFC and ABR. Higher mean values of Ca were identified and related to the ABR material, which provided more Ca ions than BFC. The comparison of Ca and P between materials showed a significant difference in the amount of Ca provided by ABR versus BFC. ABR restorations presented a thicker, and superior remineralization interface compared to the bulk-fill resin composite. CLINICAL SIGNIFICANCE: Activa BioActive Restorative restorations presented a thicker and superior remineralization interface compared to the bulk-fill resin composite.

Clinical performance of resin-matrix ceramic partial coverage restorations: a systematic review.

OBJECTIVE: To evaluate clinical performance of the new CAD/CAM resin-matrix ceramics and compare it with ceramic partial coverage restorations. MATERIALS AND METHODS: An electronic search of 3 databases (The National Library of Medicine (MEDLINE/PubMed), Scopus, and the Cochrane Central Register of Controlled Trials) was conducted. English clinical studies published between 2005 and September 2020 that evaluated the clinical performance of CAD/CAM resin-matrix ceramics inlays, onlays, or overlays were selected. The primary clinical question was applied according to PICOS strategy (Population, Intervention, Comparison, Outcome, Study design). The included studies were individually evaluated for risk of bias according to the modified Cochrane Collaboration tool criteria. RESULTS: A total of 7 studies were included according to the established inclusion and exclusion criteria. From the included studies, 6 were randomized clinical trials while one study was longitudinal observational study without control group. According to the results of the included studies, the success rate of CAD/CAM resin-based composite ranged from 85.7 to 100% whereas the success rate reported for ceramic partial coverage restorations ranged from 93.3 to 100%. Fractures and debondings are found to be the most common cause of restorations failure. CONCLUSION: CAD/CAM resin-based composite can be considered a reliable material for partial coverage restorations with clinical performance similar to glass ceramic restorations. However, this result needs to be confirmed in long-term evaluations. CLINICAL RELEVANCE: CAD/CAM resin-based composites provide a potential alternative to ceramic indirect restorations. However, clinicians must be aware of the lake of knowledge regarding long-term outcome.

Long-term evaluation of early-enamel lesions treated with novel experimental tricalcium silicate paste: A 2-year randomized clinical trial.

OBJECTIVE: The aim of the current study is to evaluate the remineralization potential of experimental tricalcium silicate (TCS) paste in comparison with more popular remineralizing agents like silver diamine fluoride potassium iodide (SDF-KI) and casein phosphopeptide amorphous calcium phosphate (CPP-ACP) on early enamel lesions. MATERIALS AND METHODS: Forty-five patients in the age range of 15-50 years had early enamel lesions on the buccal surface of molar teeth. The patients were randomly divided into three treatment groups (SDF-KI, CPP-ACP, and TCS group) with 15 patients per group. Lesions were evaluated clinically by DIAGNOdent pen immediately and after 3,6,12, and 24 months of treatment. RESULTS: The study was completed with 45 patients and 92 teeth. Twice-daily application of CPP-ACP and TCS paste showed a significant remineralization effect on early enamel lesions after 24 months (p < 0.001). Also, annual application of SDF-KI showed a significant remineralization effect after 24 months (p < 0.001). There was a significant difference between (SDF-KI and CPP-ACP) and (SDF-KI and TCS) at the different follow-up periods 3,6,12, and 24 months (p < 0.001). Meanwhile, there was no significant difference between CPP-ACP and TCS at the mentioned follow-up periods (p > 0.05). CONCLUSION: TCS showed potential remineralization for early enamel lesions. CLINICAL RELEVANCE: Experimental TCS is a promising remineralizing agent for management of early enamel lesions.

Effect of different surface treatments on resin-matrix CAD/CAM ceramics bonding to dentin: in vitro study.

BACKGROUND: Evaluating the effect of different surface treatment methods on the micro-tensile bond strength (µTBS) of two different resin-matrix computer-aided design/computer-aided manufacturing (CAD/CAM) ceramics (RMCs). METHODS: A standardized inlay preparations were performed on 100 intact maxillary premolars. According to the type of the restorative material, the teeth were randomly divided into two equally sized groups (n = 50): (polymer-infiltrated ceramic (Vita Enamic) and resin-based composites (Lava Ultimate)). The inlays were fabricated using CAD/CAM technology. In each group, the specimens were randomly assigned to five subgroups (n = 10) according to the surface treatment method: group 1 used was the control group (no surface treatment); group 2, was treated with air abrasion with 50 µm Al2O3 (A) and universal adhesive (UA); group 3, was treated with air abrasion with 50 µm Al2O3 (A) and silane coupling agent (S); group 4, was treated with hydrofluoric acid (HF) and universal adhesive (UA) and group 5, was treated with Hydrofluoric acid (HF) + silane coupling agent (S). The inlays were then cemented to their respective preparations using dual-cure self-adhesive resin cement (RelyX U200, 3 M ESPE) according to the manufacturer's instructions. The µTBS test was conducted in all groups, and stereomicroscope and scanning electron microscope were used to inspect the failure mode. The data were statistically analyzed using a two-way analysis of variance (ANOVA) and Tukey's post-hoc multiple comparison tests at a significance level of p < 0.05. RESULTS: Surface treatments significantly increased the µTBS of the materials compared to the control group (p < 0.05). For CAD/CAM RBCs, the µTBS value highest in group 2 whereas, for PICN, the µTBS value was highest in group 3. Cohesive failure of CAD/CAM restorative material was the most predominant mode of failure in all treated groups, whereas adhesive failure at restoration-cement interface was the most predominant failure mode in the control group. CONCLUSION: Surface treatments increase the µTBS of resin-matrix CAD/CAM ceramics to tooth structure. Air abrasion followed by universal adhesive and hydrofluoric acid followed by silane application appears to be the best strategies for optimizing the bond strength of CAD/CAM RBCs and PICN respectively.

A new method of evaluation of fracture patterns following microtensile bond strength testing using polarized light microscopy.

PURPOSE: This work describes a new method using polarized light microscopy to determine the failure modes of fractured beams following microtensile bond strength testing. The outcomes were validated using SEM and EDX elemental analysis. MATERIALS AND METHODS: Resin adhesives and resin composites bonded to caries-free dentin samples as well as disks of adhesive and composite were observed with reflected polarized light microscopy (PLM) to obtain standard images. A set of beams fractured in the microtensile bond test were observed with PLM and compared with the standard images to determine failure mode through PLM color matching with the standard dentin, adhesive, or composite images. Samples were analyzed by EDX under SEM and compared with the PLM outcomes. RESULTS: Reflected PLM images showed that the fractured surfaces covered with resin-based materials (adhesives or composite) appeared pink in color, in contrast to dentin surfaces, which appeared yellow. EDX mapping together with SEM observation confirmed the results obtained by PLM. CONCLUSION: The results of EDX mapping and SEM observation showed that the use of polarized light microscopy is a simple, viable method for differentiation between the resin-covered dentin surfaces for determining fracture pattern analysis after bond testing.

Introduction of "qpdb" teeth numbering system.

This manuscript introduces a new method for teeth numbering system. The primary rationale of lunching this system was to solve previous numbering systems' drawbacks. Furthermore, to keep simplicity and ease of reading and inputting data. The outcome of a questionnaire disseminated among 66 personnel showed the confusion existing among currently used tooth numbering systems. The 'qpdb' system divided the oral cavity into four quadrants, each quadrant represented by alphabetical English letter (q, p, d & b). In spite of being a promising system, this new system lacks the real usage and application, and need more future studies to prove its validity.

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.

Effect of ethanolic extract of propolis on antibacterial and microshear bond strength of glass-ionomer restorations to dentin.

Objectives: This study was conducted to evaluate the effect of ethanolic extract of propolis on antibacterial and microshear bond strength of glass ionomer restorations to dentin. Materials and methods: Conventional glass ionomer cement (Equia forte, GC Tokyo, Japan), resin-modified glass ionomer (Fuji II LC, GC Tokyo, Japan) and propolis powder (dried extract from honey bees) materials were used in this study. Both conventional glass ionomer and resin-modified glass ionomer were modified by two different concentrations of ethanolic extract of propolis (10 % and 25 % EEP). For antibacterial test, Streptococcus mutans strain was spread on agar petri dishes using a sterile swab. Discs of both glass ionomer restorative materials (without adding EEP, with 10 % EEP and with 25 % EEP) were fabricated within the agar plates. Antibacterial activity was evaluated by measuring the inhibition zones around each disc. For microshear bond strength test, 60 healthy human permanent molars were prepared by cutting occlusal surface and expose the dentin at the height of contour of all teeth then conditioned using poly acrylic acid conditioner, both glass ionomer restorative materials (without adding EEP, with 10 % EEP and with 25 % EEP) were mixed and applied on conditioned dentin surface by using tygon tube. Microshear bond strength was evaluated by the universal testing machine. Results: Two-way ANOVA test revealed that both glass ionomer type and different concentrations of EEP had significant effect on the antibacterial test results and microshear bond strength values (p < 0,05). Glass ionomer restorative material with 25%EEP had the highest antibacterial values whereas glass ionomer restorative material without modifications (control groups) had the lowest values. Resin-modified glass ionomer without any modification (control group) had the highest bond strength while resin-modified glass ionomer with 25%EEP had the lowest bond strength. Conclusions: Incorporation of ethanolic extract of propolis to glass ionomer restorative material increases the antibacterial effects of both conventional GIC and RMGI. Inspite of this advantage, it seems that it has deleterious effect on microshear bond strength to dentin.

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.

Inhibition of Caries around Restoration by Ion-Releasing Restorative Materials: An In Vitro Optical Coherence Tomography and Micro-Computed Tomography Evaluation.

The objective of this study was firstly to assess the demineralization inhibitory effect of ion-releasing restorations in enamel adjacent to restoration using a biofilm caries model and secondly to compare the effect to that in a chemical caries model. Fifty-six bovine incisors were filled with either Surefil one (SuO), Cention N (CN) (both ion-releasing materials), Ketac-Molar (GIC) or Powerfill resin composite (RC). The restored teeth were then randomly divided into 2 groups according to the used caries model (biofilm or chemical caries model). The micro-computed tomography (MicroCt) and optical coherence tomography (OCT) outcome measures used to evaluate demineralization inhibition effects were lesion depth, LD and increase in OCT integrated reflectivity, ΔIR, at five different depths. It was observed that all outcome measures of CN were statistically the same as those of GIC and conversely with those of RC. This was also the case for SuO except for LD, which was statistically the same as RC. When comparing the two caries models, LD of the biofilm model was statistically deeper (p < 0.05) than the chemical model for all four materials. In conclusion, CN and SuO have similar demineralization inhibitory effects as GIC, and the biofilm caries model is more discriminatory in differentiating demineralization inhibitory effects of ion-releasing restorative material.

Remineralization of early enamel lesions with a novel prepared tricalcium silicate paste.

To evaluate the remineralization potential of prepared tricalcium silicate (TCS) paste compared to silver diamine fluoride-potassium iodide (SDF-KI) and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on artificial enamel lesions. Thirty permanent sound molars were collected for the study. After cleaning, root cutting, and applying acid-resistant nail varnish, leaving a 4 × 4 mm buccal window, the teeth were subjected to demineralization process. The teeth were divided into three treatment groups (n = 10). In each group, the teeth were sectioned buccolingually to obtain two halves (30 self-control and 30 experimental halves). The self-control halves were subjected to cross-sectional microhardness (CSMH), energy-dispersive X-ray spectroscopy at 50, 100, and 150 µm from the external enamel surface, and micromorphological analysis at the superficial enamel surface. The experimental halves were subjected to the same tests after 30 days of remineralization. Three-way analysis of variance (ANOVA) outcomes showed no significant difference in CSMH after treatment among the three different groups at the different levels (p > 0.05). Meanwhile, three-way ANOVA outcomes showed a significant difference in calcium/ phosphate ratio after treatment among the three different groups at the different levels. (p < 0.05). The tricalcium silicate paste used in this study showed potential remineralization in subsurface enamel lesions.

Secondary caries and marginal adaptation of ion-releasing versus resin composite restorations: a systematic review and meta-analysis of randomized clinical trials.

This systematic review was aimed to evaluate occurrence of secondary caries and marginal adaptation in ion-releasing materials versus resin composite. Electronic search of PubMed, Scopus, and Open Grey databases with no date or language restrictions until May 21st, 2021, was conducted. Randomized clinical trials that compared ion-releasing restorations versus resin composite were included. For quantitative analysis, a random-effects meta-analysis with risk difference as an effect measure and a 95% confidence interval was used. Quality of evidence was assessed using The Grading of Recommendations, Assessment, Development, and Evaluation criteria. The risk of bias was evaluated using the Cochran Collaboration Risk of Bias tool. The inclusion criteria were met by 22 studies, and 10 studies were included in the meta-analysis. Three follow-up periods (1 year, 18 months-2 years, and 3 years) were evaluated. The overall quality of evidence for secondary caries and marginal adaptation outcomes was low. The results of the meta-analysis showed no significant difference (p > 0.05) in both outcomes between ion-releasing materials and resin composite. The occurrence of secondary caries was not dependent on the nature of the restorative material. It is more likely a complex process that involves the same risk factors as primary carious lesions.

Influence of material type, thickness and storage on fracture resistance of CAD/CAM occlusal veneers.

OBJECTIVES: The present study aimed to evaluate the effect of restoration thickness, CAD/CAM material, and 6 months of artificial saliva storage on the fracture resistance of occlusal veneers. MATERIALS AND METHODS: A total of 84 intact maxillary molars were sectioned 4.0 mm occlusal to the cementoenamel junction to expose the dentine. The teeth were assigned into 3 main groups according to the type of restorative material (e.max CAD, Vita Enamic, and Lava Ultimate). In each group, the teeth were allocated into 2 subgroups (n = 14) according to restoration thickness (1.0 and 1.5 mm). The veneers were adhesively bonded using dual-cure self-adhesive luting agent. A total of 42 specimens comprising half the tested subgroups were stored in distilled water for 24-h before the test. The remaining half was stored in artificial saliva at 37 ± 1 °C in an incubator for 6 months. All specimens (n = 84) were subjected to 5000 thermal cycles between 5 and 55 °C ± 2 before the fracture resistance test. The maximum force at fracture was recorded in Newton. Failure mode was analyzed using a stereomicroscope. The results were analyzed using a parametric Three-way ANOVA test. RESULTS: The results of the Three-way ANOVA test revealed that material type and restoration thickness significantly affected fracture resistance values (p < 0.5), while 6 months of storage in artificial saliva had no significant effect on mean fracture resistance values (p˃0.5). The most common failure patterns in CAD/CAM resin composite and polymer-infiltrated ceramics were scores I and score II. For glass ceramic groups, score IV and III were more dominant. CONCLUSIONS: All the tested CAD/CAM restorations in both thicknesses exhibited fracture resistance values exceeding normal and parafunctional bite forces. Polymer-infiltrated ceramics and CAD/CAM resin composite veneers showed more favorable fracture patterns.

Effect of Different Polishing Systems on the Surface Roughness and Gloss of Novel Nanohybrid Resin Composites.

OBJECTIVES: To evaluate the surface roughness and gloss of three nanohybrid resin composites after polishing with three different polishing systems. MATERIALS AND METHODS: A total number of 112 disc specimens (10 × 3 mm) were prepared from nanohybrid-Empress Direct (ID), Grandio (GR), Filtek Z350 (Z350) and a microhybrid resin composite restorative materials-Filtek Z250 (Z250). Following 24-hour storage in 37°C distilled water, each composite group (n = 28) was assigned into four groups (n = 7) according to finishing/polishing (F/P) system: Mylar strip, Optrapol, Politip, and Sof-Lex (SL). The surface roughness (Ra, mm) was measured by a novel three-dimensional method using an image analysis software attached to an environmental scanning electron microscope. A glossometer was used to measure the surface gloss. RESULTS: Statistical analysis used was ANOVA test. Two-way Anova test revealed that the "type of composite" and "F/P techniques" had a significant effect on both surface roughness and gloss of the tested resin composite materials (p < 0.05). Tukey's post hoc test showed that ID, GR, and Z350 revealed lower surface roughness and higher surface gloss than Z250 within the same polishing system (p < 0.05). Sof-Lex polishing discs produced the lowest surface roughness and highest surface gloss values compared with Optrapol and Politip (p < 0.05). CONCLUSION: The tested F/P systems provided comparable surface roughness and gloss for nanohybrid composites. The Sof-Lex system provided the best surface roughness and gloss for nanohybrid composites.

Global Oral Health Policies and Guidelines: Using Silver Diamine Fluoride for Caries Control.

Silver diamine fluoride (SDF) was developed in Japan in the 1960s. It is a clear solution containing silver and fluoride ions. Because of its anti-bacterial and remineralizing effect, silver diamine fluoride has been used in managing dental caries for decades worldwide. This paper aims to summarize and discuss the global policies, guidelines, and relevant information on utilizing SDF for caries management. SDF can be used for treating dental caries in most countries. However, it is not permitted to be used in mainland China. Several manufacturers, mainly in Australia, Brazil, India, Japan, and the United States, produce SDF at different concentrations that are commercially available around the world. The prices differ between contents and brands. Different government organizations and dental associations have developed guidelines for clinical use of SDF. Dental professionals can refer to the specific guidelines in their own countries or territories. Training for using SDF is part of undergraduate and/or postgraduate curriculums in almost all countries. However, real utilization of SDF of dentists, especially in the private sector, remains unclear in most places because little research has been conducted. There are at least two ongoing regional-wide large-scale oral health programs, using SDF as one of the components to manage dental caries in young children (one in Hong Kong and one in Mongolia). Because SDF treatment does not require caries removal, and it is simple, non-invasive, and inexpensive, SDF is a valuable strategy for caries management in young children, elderly people, and patients with special needs. In addition, to reduce the risk of bacteria or virus transmission in dental settings, using SDF as a non-aerosol producing procedure should be emphasized under the COVID-19 outbreak.

Fracture resistance of CAD/CAM occlusal veneers: A systematic review of laboratory studies.

OBJECTIVE: The purpose of this systematic review was to summarize scientific evidence that evaluates in vitro fracture and fatigue strength of occlusal veneers in different thicknesses, CAD/CAM materials, and under different aging methodologies. MATERIALS AND METHODS: An electronic search of 3 English databases (The National Library of Medicine (MEDLINE/PubMed), ScienceDirect, and EBSCOhost) was conducted. Laboratory studies published between September 2009 and October 2019 that evaluated fracture or fatigue strength of CAD/CAM occlusal veneers and used human teeth were selected. The included studies were individually evaluated for the risk of bias following a predetermined criterion. The outcomes assessed included the types of the restorative material, the thickness of the veneers, and aging methods. RESULTS: A total of 12 studies fulfilled the inclusion criteria. Most of the included studies (86%) evaluated the fracture strength of occlusal veneers. Two studies evaluated fatigue resistance. There was a significant relationship between the choice of materials and fracture strength. Polymeric materials performed better in fatigue testing in comparison to ceramics. Lithium silicate-based glass ceramics showed more favorable outcomes in a thickness of 0.7-1.0 mm. Fracture resistance values in all the included studies exceeded maximum bite forces in the posterior region. CONCLUSIONS: The outcomes of this systematic review suggest that occlusal veneers can withstand bite forces in the posterior region, whereas the measurement of thickness should be standardized in order to have a fair comparison. Further research needs to be conducted to evaluate the longevity of this type of restorations clinically.

The effect of four materials on direct pulp capping: An animal study.

The aim of this study was to investigate the outcomes of direct pulp capping performed with two types of tricalcium silicate-based materials (mineral trioxide aggregate/MTA and Biodentine/BD); nano-hydroxyapatite (nHAP) crystals or calcium hydroxide (CH) in dogs. Following mechanical exposure, the pulps were randomly capped with one of the four materials. Histological analyses were performed to examine the outcomes after 7 days or 3 months. At 7 days, BD and nHAP showed significantly less inflammatory cell response than MTA and CH. At 3 months, the inflammatory cell response and tissue necrosis were significantly higher in the CH group. There was no significant difference between the tested materials in the calcific bridge formation after 7 days; however, a significant difference was noticed at the 3-month period. Tricalcium silicate-based cements and nHAP are potential alternatives to CH in vital pulp therapy following accidental pulp exposure.