Preventive and restorative alternatives to caries by irradiation: a scoping review.

PURPOSE: This study is to conduct a comprehensive scoping review to map scientific evidence and clarify concepts regarding the commonly recommended preventive and restorative dental treatments for patients diagnosed with head and neck cancer (HNC) and subjected to radiotherapy. MATERIAL AND METHODS: This systematic scoping review was performed under the PRISMA-ScR guidelines. The study's experimental design was registered in the Open Science Framework. In vitro studies that evaluated preventive and restorative dental treatment over 50 Gy radiation doses were included. The search was conducted in November 2023 in five electronic databases (PubMed, Scopus, Web of Science, Cochrane Library, and Embase) without language or date restriction. A search strategy was applied based on keywords, MeSh terms, or synonyms. A descriptive analysis was conducted. RESULTS: A total of 49 studies, out of 3679 original articles identified, were included and reviewed. Of the included studies, three evaluated saliva stimulants and 35 evaluated fluoride-based preventive materials: gel (n = 18) toothpaste (n = 11) mouth rinse (n = 8) and varnish (n = 5) while 14 evaluated restorative materials: resin composite (n = 12) glass ionomer cement (n = 6) and amalgam (n = 1) Of those studies, 36 were clinical trials and 13 were in vitro studies. CONCLUSION: Fluoride gel was the most frequently recommended preventive material for preventing radiation caries with supportive clinical evidence. Resin composite and glass ionomer were the most frequently used restorative materials, respectively. However, there is not yet clinical evidence to support the use of resin composite in irradiated teeth.

Long term results of glass ionomer ossiculoplasty.

OBJECTIVE: To analyze and compare the early and late post-operative results of glass ionomer bone cement (GIBC) used in ossiculoplasty. METHODS: The pre-operative, early post-operative (3 months) and late post-operative (> 2 years) audiometric findings, namely the pure-tone average (PTA), bone conduction threshold (BCT) and air-bone gap (ABG) of 40 patients who underwent GIBC ossiculoplasty for different etiologies were analyzed. Early and late results were compared. Also, the patients were grouped in terms of prognostic factors and applied ossiculoplasty techniques, and the results were compared between the groups. RESULTS: There were statistically significant improvements in the pure-tone average and air-bone gap of the patients in the early post-operative period (PTA from 59.60 ± 15.95 to 40.37 ± 17.83 and ABG from 37.12 ± 11.18 to 19.78 ± 10.41, p < 0.001 for both). There were no statistically significant changes in any of the audiometric parameters in the late post-operative period (PTA from 40.37 ± 17.83 to 39.79 ± 17.91, ABG from 19.78 ± 10.41 to 19.32 ± 9.60, BCT from 17.99 ± 12.71 to 18.31 ± 13.99, p > 0.05 for all). Presence of tympanosclerosis was found to be the only prognostic factor to affect the outcome. CONCLUSION: GIBC is a safe and reliable material for ossiculoplasty, which maintains its ability to conduct sound in the long-term follow-up.

Novel microbial synthesis of titania nanoparticles using probiotic Bacillus coagulans and its role in enhancing the microhardness of glass ionomer restorative materials.

Dental caries is a commonly occurring non-communicable disease throughout the world that might compromise the quality of any individual's life. Glass ionomer cements (GIC) are the most acceptable restorative materials due to their ease of manipulation, minimal tooth loss and least invasive strategy; however, they lack mechanical stability that has become a point of concern. Nanoparticles (NPs) are an outstanding option for modifying and enhancing the properties of dental materials. The focus of this study was to prepare novel, biocompatible titania dioxide (TiO2) NPs as a dental-restorative material using an efficient probiotic Bacillus coagulans. The prepared NPs were incorporated into glass ionomer restorative material at varying concentrations and investigated for cell viability percentage, microhardness and surface morphology. Results indicated that pure 100% anatase phase TiO2 NPs with particle size of 21.84 nm arranged in smooth, spherical agglomerates and clusters forms. These NPs depicted cell viability > 90%, thus confirming their non-cytotoxic behavior. GIC restorative materials reinforced by 5% titania (TiO2) NPs demonstrated the highest microhardness in comparison to the control group and other experimental groups of the study. Surface morphology analysis revealed a reduction in cracks in this novel dental-restorative material supporting its compatible biological nature with better hardness strength and negligible crack propagation. Overall, these results indicated that TiO2 NPs produced using a biological approach could be easily used as restorative materials in dental applications.

Long-term clinical comparison of a resin-based composite and resin modified glass ionomer in the treatment of cervical caries lesions.

This 72-month study compared the clinical effectiveness of a resin-based composite (RBC) (Spectrum TPH3, Dentsply Sirona) with a resin-modified glass ionomer cement (RMGIC) (Riva Light Cure, SDI) in restoring cervical caries lesions (CCLs). Thirty-three patients, each with at least two CCLs, were enrolled. After caries removal, the dimensions of the cavities were recorded. In a split-mouth study design, a total of 110 restorations were randomly placed. Fifty-five restorations were placed with RBC using an etch-and-rinse adhesive system (Prime&Bond NT, Dentsply Sirona), while the remaining 55 were restored with RMGIC. The restorations were assessed at baseline, 6, 12, 18, 24, 36, 60, and 72 months according to modified USPHS criteria. Statistical analysis included Pearson Chi-square, Friedman tests, Kaplan Meier, and Logistic Regression analysis (p < 0.05). After 72 months, 47 restorations in 19 patients were evaluated (55% follow-up rate). Seventy-five percent of the RBC (n = 26) and 74% (n = 21) of the RMGIC restorations were fully retained. There were no significant differences between materials regarding retention and marginal adaptation (p > 0.05). Cavity dimensions, caries activity, and retention exhibited no correlation (p > 0.05). The increase in marginal staining in both groups over time was significant (p < 0.001). RMGIC restorations exhibited higher discoloration than RBC restorations (p = 0.014). At 72 months, three secondary caries lesions were detected in both restoration groups: two RMGIC and one RBC. There were no reports of sensitivity. After 72 months, both RBC and RMGIC restorations were clinically successful, with similar retention and marginal adaptation scores. However, it is noteworthy that RMGIC restorations tend to discoloration over time compared to RBC. The trial is registered in the database of "Clinical Trials". The registration number is NCT0372-2758, October 29, 2018.

Could bulk fill glass hybrid restorative materials replace composite resins in treating permanent teeth? A randomized controlled clinical trial.

OBJECTIVE: This study aims to compare the clinical and radiographic efficacy of Equia system bulk fill glass hybrid material with composite resins in the permanent restoration of pediatric patients' permanent teeth. MATERIALS AND METHODS: The study included 44 pediatric patients aged 8-16 who applied to Necmettin Erbakan University Pediatric Dentistry Department. The groups were formed as symmetrical teeth in the same patient using the split-mouth design. The study included class I caries lesions of 144 permanent teeth. Group 1 was restored with the Equia system bulk fill glass hybrid material (Equia Forte HT + Equia Forte Coat [GC, Co, Tokyo, Japan]) (n = 72) and Group 2 with the Charisma Smart universal composite resin (Kulzer, Gmbh, Hanau, Germany) + Clearfil SE Bond (Kuraray, Noritake, Sakazu, Okayama) (n = 72). Evaluations were performed clinically and radiographically by two physicians in 2nd week, 3rd month, 6th month, and 12th month and the results were recorded. Clinical evaluation was carried out using modified-USPHS criteria. Obtained data were statistically analyzed using Kendall's W test and Cochran's Q test for the comparison within the group, and the Chi-square test for the comparison between groups. RESULTS: Among the materials utilized in the study, there was no statistically significant difference in marginal adaptation, marginal discoloration, retention, anatomical form, postoperative sensitivity, and secondary caries according (p > 0.05). Group 2 outperformed statistically significant Group 1 in terms of color match in all periods (p < 0.05). While there was no statistically significant difference in surface structure between the groups in 2nd week and 3rd month (p > 0.05), there was a statistically substantial difference in 6th, and 12th months (p < 0.05). No secondary caries or periapical lesions were found in any restorations during radiographic evaluation. CONCLUSION: After a year, the clinical performance of both Equia and composite resins was equivalent and successful in the majority of the measures against which they were evaluated. CLINICAL SIGNIFICANCE: Based on the results of the research, Equia system bulk fill glass hybrid restorations are considered a viable alternative to composite resins in class I permanent teeth restorations.

The effect of mesoporous silica doped with silver nanoparticles on glass ionomer cements; physiochemical, mechanical and ion release analysis.

BACKGROUND: The purpose of the study was to evaluate the effect of adding mesoporous silica with silver nanoparticles to conventional glass ionomer cements (GIC) on its, physical, chemical, mechanical properties and ion release analysis. METHODS: Synthesized mesoporous silica with silver nanoparticles were added in 1, 3 and 5% by weight to the liquid component of GIC forming three experimental groups and compared with plain GIC as control group. Physical and chemical characterization were conducted using nano-computerized tomography (NanoCT) and Fourier transform infrared spectroscopy. Surface microhardness, water sorption and solubility were analyzed. Ion release was investigated using Inductive Coupled Plasma-Optical Emission Spectroscopy and High Performance Liquid Chromatography. Statistical analysis between different groups for the set parameters using parametric and non-parametric tests. The results were analysed using one way analysis of variance (p < 0.05). RESULTS: Synthesized mesoporous silica with silver nanoparticles were of 7.28 ± 5.0 nm in diameter with a spherical morphology. NanoCT revealed less porosities for 3 wt %. Microhardness showed a statistically significant difference for 5 wt% at day 1 and 21 ( p < 0.0001). Water sorption values decreased significantly on day 14 compared to day 7 for control, 1, 3 and 5 wt%. Control specimens showed highest concentration of fluoride release followed by 5, 3 and 1 wt%. CONCLUSION: Mesoporous silica with silver nanoparticles modified glass ionomer cements showed comparable microhardness to conventional GIC. Ion release was evident from the modified specimens. Silver remained within the GIC for atleast four weeks following incorporation.

Color change of tooth-colored restorative materials bonded to silver diamine fluoride-treated dentine: a systematic review.

BACKGROUND: The desirable properties of silver diamine fluoride (SDF) make it an effective agent for managing dental caries and tooth hypersensitivity. There are several clinical instances that SDF application might precede the placement of direct tooth-colored restorations. On the other hand, SDF stains demineralized/carious dental tissues black, which might affect the esthetic outcomes of such restorations. Color is a key parameter of esthetics in dentistry. Therefore, this study aims to systematically review dental literature on color/color change of tooth-colored restorations placed following the application of SDF on dentine. METHODS: Comprehensive search of PubMed, Embase, Scopus and ISI Web of Science databases (until August 2023) as well as reference lists of retrieved studies was performed. In vitro studies reported color or color change of tooth-colored restorative materials applied on SDF-treated dentine were included. Methodological quality assessment was performed using RoBDEMAT tool. Pooled weighted mean difference (WMD) and 95% confidence interval (95% CI) was calculated. RESULTS: Eleven studies/reports with a total of 394 tooth-colored restorations placed following a) no SDF (control) or b) SDF with/without potassium iodide (KI)/glutathione dentine pre-treatments were included. Color change was quantified using ∆E formulas in most reports. The pooled findings for the comparison of resin-based composite (RBC) restorations with and without prior 38% SDF + KI application revealed no statistically significant differences in ∆E values at short- and long-term evaluations (~ 14 days: WMD: -0.56, 95% CI: -2.09 to 0.96; I2: 89.6%, and ~ 60 days: WMD: 0.11; 95% CI: -1.51 to 1.72; I2: 76.9%). No studies provided sufficient information for all the items in the risk of bias tool (moderate to low quality). CONCLUSIONS: The limited evidence suggested comparable color changes of RBC restorations with and without 38% SDF + KI pre-treatment up to 60 days. The included studies lacked uniformity in methodology and reported outcomes. Further studies are imperative to draw more definite conclusions. PROTOCOL REGISTRATION: The protocol of this systematic review was registered in PROSPERO database under number CRD42023485083.

Evaluation of setting kinetics, mechanical strength, ion release, and cytotoxicity of high-strength glass ionomer cement contained elastomeric micelles.

BACKGROUND: Low mechanical properties are the main limitation of glass ionomer cements (GICs). The incorporation of elastomeric micelles is expected to enhance the strength of GICs without detrimentally affecting their physical properties and biocompatibility. This study compared the chemical and mechanical properties, as well as the cytotoxicity, of elastomeric micelles-containing glass ionomer cement (DeltaFil, DT) with commonly used materials, including EQUIA Forte Fil (EF), Fuji IX GP Extra (F9), and Ketac Molar (KT). METHOD: Powder particles of GICs were examined with SEM-EDX. Setting kinetics were assessed using ATR-FTIR. Biaxial flexural strength/modulus and Vickers surface microhardness were measured after immersion in water for 24 h and 4 weeks. The release of F, Al, Sr, and P in water over 8 weeks was analyzed using a fluoride-specific electrode and ICP-OES. The toxicity of the material extract on mouse fibroblasts was also evaluated. RESULTS: High fluoride levels in the powder were detected with EF and F9. DT demonstrated an initial delay followed by a faster acid reaction compared to other cements, suggesting an improved snap set. DT also exhibited superior flexural strength than other materials at both 24 h and 4 weeks but lower surface microhardness (p < 0.05). EF and F9 showed higher release of F, Al, and P than DT and KT. There was no statistically significant difference in fibroblast viability among the tested materials (p > 0.05). CONCLUSIONS: Elastomeric micelles-containing glass ionomer cement (DT) exhibited satisfactory mechanical properties and cytocompatibility compared with other materials. DT could, therefore, potentially be considered an alternative high-strength GIC for load-bearing restorations.

Efficacy of bioactive materials in preventing Streptococcus mutans-induced caries on enamel and dentine.

The study investigated the ability of bioactive materials used to restore enamel and dentine specimens to prevent caries. Enamel (n = 50) and dentine (n = 50) specimens were obtained from bovine incisors, prepared, and randomly allocated to one of five groups according to the restorative treatment: alkasite without adhesive system; alkasite with adhesive system; high viscosity glass ionomer cement; resin composite; no restoration; negative control group. Specimens were restored, exposed to a thermal cycling aging protocol, sterilized, and exposed to a cariogenic challenge induced by Streptococcus mutans and then submitted to surface and subsurface microhardness tests and polarized light microscopy to verify the caries lesion development in enamel or dentine surrounding the restorative materials. Data were analyzed using one-way ANOVA. In enamel and dentine, glass ionomer cement, alkasite without and with adhesive system presented a lower percentage surface microhardness loss than resin composite and negative control. Enamel subsurface microhardness presented no statistically significant differences between glass ionomer cement, alkasite without and with adhesive system. Glass ionomer cement also did not present statistically significant differences from resin composite and the negative control. In dentine, glass ionomer cement showed the highest subsurface microhardness values. In conclusion, bioactive restorative materials provide greater protection to enamel and dentine against surface caries development than resin composite.

Dentine Mineral Changes Induced by Polyalkenoate Cements after Different Selective Caries Removal Techniques: An in vitro Study.

This study aimed at evaluating the mineral variation induced by polyalkenoate cements in residual dentine after different caries removal methods. Ten extracted sound molars were selected, and five cavities were prepared on the occlusal surface of each specimen. Carious lesions were generated using a microbial protocol, while the caries removal was performed using bur, hand excavator, or two papain-based chemo-mechanical agents. One cavity was left unexcavated in each tooth. Cavities were restored using a zinc polycarboxylate cement (ZPC; n = 25), or a glass ionomer cement (GIC) was used (n = 25). Subsequently, the specimens were stored under simulated pulpal pressure for 45 days. Micro-CT scanning was performed after caries formation, removal, and restoration. Cavity volumes (mm3) and mineral density (MD) changes were calculated. Remineralisation ability was investigated by scanning electron microscopy (SEM) and Fourier-transformed infrared spectroscopy (FTIR). Statistical analysis was performed (5% significance level). Baseline caries, cavity volume, and MD increase after caries removal were similar to all excavation groups (p > 0.05). MD was higher in ZPC compared to GIC (p < 0.05). SEM revealed that the chemo-mechanical techniques produced a smoother dentine surface compared to mechanical methods. FTIR showed silicon-based minerals in GIC-treated dentine, while ZPC-treated presented mineral deposits characterised by amorphous calcium phosphate. In both cases, the presence of carbonates was detected on dentine surfaces. All caries removal techniques performed similarly in terms of carious dentine excavation. ZPC can be used as dentine replacement material after caries removal as it may induce higher MD increase in residual dentine via deposition of calcium phosphates, compared to GIC.

Modification of glass-ionomer cement properties by quaternized chitosan-coated nanoparticles.

Glass ionomers (GICs), because of their qualities, are in a good position to be modified to resist masticatory stresses as permanent posterior restoration and prevent recurrent caries. The purpose of the present study was to evaluate the effect of adding quaternized chitosan-coated mesoporous silica nanoparticles (HTCC@MSNs) to conventional GIC on its mechanical properties, antimicrobial activity and fluoride release and the effect of 1- and 3-month water aging on the studied properties. HTCC@MSNs was synthesized, added to commercially available conventional GIC at 1%, 3%, and 5% by weight forming three experimental groups and compared with plain GIC as a control group. Flexural strength, modulus, Vickers microhardness and wear volumes were evaluated. Antibacterial activity was tested against Streptococcus mutans and fluoride release in de-ionized water was measured. All properties were evaluated before and after one- and three-month aging (n = 10 specimens per test/per time). Two-way ANOVA was used for statistical analysis. Characterization confirmed successful preparation of HTCC@MSNs. The flexural strength, modulus, hardness and wear resistance of the GICs improved significantly by adding 1-3% HTCC@MSNs, while 5% HTCC@MSNs group showed no significant difference compared to control group. Bacterial inhibition zones and fluoride release increased proportionally to the amount of filler added. Mechanical properties were improved by artificial aging. Fluoride release values, and bacterial inhibition zones decreased with aging for all groups. HTCC@MSNs as a filler with the optimized proportion provides strengthening and antibacterial effect. In addition, aging is an important factor to be considered in evaluating experimental fillers.

Assessment of genotoxicity of glass ionomer cements: a systematic review.

To evaluate, through a systematic review, the assessment of genotoxicity of glass ionomer cements in vitro and in vivo. A systematic review was performed with the problem, intervention, control, and outcomes (PICOS) strategy, aiming to answer the following question: "Can glass ionomer cements induce genetic damage in vitro and in vivo?" A systematic search was performed in the following electronic databases: PubMed (including MedLine), Web of Science, and Scopus. The quality of included studies was assessed using the Effective Public Health Practice Project (EPHPP). After the authors performed the review of all articles, a total of 13 manuscripts met all the inclusion criteria in the systematic review. Following the parameters of the EPHPP, eight articles were classified as strong or moderate quality. The other ones (five studies) were weak. Taken together our results demonstrated that, six studies reported genotoxicity of the modified glass ionomer cements tested and two studies concluded that the effect of genotoxicity was time dependent.

Effectiveness of glass ionomer cements in the restorative treatment of radiation-related caries - a systematic review.

PURPOSE: The aim of this systematic review was to investigate the clinical effectiveness of glass ionomer cements (GICs) compared to other restorative materials in the treatment of radiation-related caries. METHODS: Two independent researchers searched literature databases (PubMed, Scopus, Web of Science, Cochrane Library, Lilacs/BBO) and the grey literature to identify clinical trials that compared GICs with other restorative materials for the treatment of radiation-related caries. The clinical criteria considered for the performance of the restorations were based on the parameters of marginal adaptation/anatomical form, secondary caries, retention, and cumulative failures of the restorations. The methodological quality and risk of bias were evaluated using the Cochrane Collaboration tool. RESULTS: From a total of 511, only four articles fulfilled the inclusion criteria. Conventional GIC restorations presented higher marginal adaptation failures than the resin-modified glass ionomer cements (RM-GICs) and composite restorations in all of the follow-up periods. Secondary caries was not observed in conventional GIC restorations throughout the follow-up periods, in three out of four of the included studies. RM-GICs and composite restorations showed significantly lower cumulative failure rates than conventional GICs at 6-, 12-, and 18-month follow-ups. CONCLUSION: Due to insufficient scientific evidence, it was not possible to conclude that GICs are more effective than other restorative materials for the treatment of radiation-related caries.

The effect of zeolite incorporation on the physical properties of silver-reinforced glass ionomer cement.

Zeolite can impart antibacterial properties to dental materials in the long-term when incorporated with inorganic cations. However, due to its porosity, it may jeopardize the mechanical integrity of the dental material. The aim of this project was to determine the effect on physical properties when zeolite is added to commercially available Ag-reinforced Glass Ionomer Cement (GIC). Sample groups were prepared according to the percentage of zeolite-clinoptilolite (0% - control, 0.5%, 1%, 2%, and 4% wt) added to Ag-GIC. Water sorption, solubility, Vickers hardness, and flexural strength were determined. Specifically, 10 × 2 mm circular disks were fabricated for the Vickers hardness, water sorption, and water solubility tests and 25 × 5 × 2 mm bars were created for the flexural strength test. The results from the surface hardness, water sorption, and flexural strength tests suggested that adding 0.5-4% wt of zeolite to Ag-reinforced GIC did not diminish its physical properties. However, the water solubility results showed that higher concentrations (2-4% wt) of zeolite had a statistically significant increase in water solubility compared to the control. Up to 4% wt zeolite can be incorporated into Ag-reinforced GIC without compromising mechanical properties. Incorporation of 0.5-1% wt zeolite to Ag-reinforced GIC will maintain an adequate surface hardness, water sorption, and flexural strength without compromising water solubility. Further research is needed to determine the effects of higher water solubility on clinical efficacy of zeolite modified Ag-GIC. Graphical abstract.

Atraumatic Restorative Treatment-Sealed versus Nonsealed First Permanent Molars: A 3-Year Split-Mouth Clinical Trial.

To investigate the efficacy of atraumatic restorative treatment (ART) sealants vs. no sealant in preventing the development of dentine caries lesions in first permanent molars over a period of 3 years. A total of 187 schoolchildren (aged 6-8 years) from a low-income population presenting the 4 first permanent molars without clinically detectable dentine caries lesions were selected to be part of a split-mouth clinical trial. All 4 first permanent molars were investigated in this trial and the children's mouth was split vertically into left and right sides; therefore, 2 molars were randomly allocated to receive ART sealants, while the other 2 molars remained nonsealed. All children received toothbrushing instructions and dietary advice every 6 months for a period of 3 years. Clinical evaluations were performed after 3, 6, 12, 18, 24, and 36 months and both sealant retention and dental caries were scored. Kaplan-Meier survival analysis, log-rank test, and Cox regression with shared frailty analysis were performed. A cavitated dentine caries lesion was considered a failure. The cumulative survival rates of dentine cavity-free first permanent molars were 90% for ART-sealed molars and 90.8% for nonsealed molars, with no statistically significantly difference between sealed and nonsealed molars (p = 0.70). The retention of sealants was not associated with the development of cavitated dentine caries and children presenting a higher baseline caries experience had greater chances of developing dentine lesions. In conclusion, the application of ART sealants was not more efficacious than nonsealing in reducing the development of dentine cavitated lesions in first permanent molars.

Clinical comparison of a micro-hybride resin-based composite and resin modified glass ionomer in the treatment of cervical caries lesions: 36-month, split-mouth, randomized clinical trial.

PURPOSE: The aim of the study was to compare the 36-month clinical performances of a micro-hybride resin based composites (RBC) and a type II resin modified glass ionomer cement (RMGIC) in the treatment of cervical caries lesions. METHODS: Thirty-three patients (23 females,  10 males) with at least two cervical caries lesions participated in this study. A total of 110 restorations were randomly placed, half using RBC (Spectrum TPH3, Dentsply Sirona) with respective adhesive system (Prime & Bond NT, Dentsply Sirona) the other half using the RMGIC (Riva Light Cure, SDI, Bayswater, Victoria, Australia). Restorations were assessed at baseline, and after 6, 12, 18, 24 and 36 months using modified USPHS criteria. The data were analyzed statistically (p < 0.05). RESULTS: Recall rate was 90.91% at 36 months. Of the RBC lesions 84.3% (n = 43) and of the RMGIC restorations 92.2% (n = 47) were fully retained at 36 months. There was no significant difference between two materials in terms of retention and marginal adaptation (p > 0.05). No relation was found between caries activity, cavity dimensions and marginal adaptation (p > 0.05) but RMGIC restorations showed significantly more discoloration than RBC restorations after 36 months (p < 0.001). CONCLUSIONS: Considering the middle-term outcomes, both materials showed clinically successful performance in the treatment of cervical caries lesions.

Translucency parameter of conventional restorative glass-ionomer cements.

OBJECTIVE: To evaluate the translucency parameter (TP) and contrast ratio (CR) of different conventional restorative glass-ionomer cements (GICs). MATERIALS AND METHODS: Eighteen brands of GICs were evaluated. Five disks of each material were made following ISO 9917-1. The luminous reflectance and Central Bureau of the International Commission on Illumination parameters of disks were evaluated using a colorimeter, against backings of white and black, to obtain the translucent parameter and contrast ratio of different brands of glass-ionomer cements. The correlation between translucency parameter and contrast ratio was assessed with the Pearson correlation test. The translucent and contrast ratio parameters values were submitted to the one-way ANOVA and Tukey test for multiple comparisons (p < 0.05). RESULTS: There was a strong inverse relationship between CR and TP (r2  = 0.94, p < 0.001). The contrast ratio decreased as translucency increased. There were significant differences in TP and CR among brands (p < 0.001). CONLUSIONS: GICs exhibit different translucency and contrast ratio behavior. Some brands of GICs presented very low TP and this condition would be unacceptable for areas with esthetic demands. In addition, TP and CR showed a strong linear relationship. CLINICAL SIGNIFICANCE: The results found in this study demonstrated that the knowledge of the translucency and CR of different conventional restorative GICs is important in order to guide clinicians in the selection of restorative GICs for anterior teeth.

Dental Applications of Carbon Nanotubes.

Glass ionomer cements and resin-based composites are promising materials in restorative dentistry. However, their limited mechanical properties and the risk of bulk/marginal fracture compromise their lifespan. Intensive research has been conducted to understand and develop new materials that can mimic the functional behavior of the oral cavity. Nanotechnological approaches have emerged to treat oral infections and become a part of scaffolds for tissue regeneration. Carbon nanotubes are promising materials to create multifunctional platforms for dental applications. This review provides a comprehensive survey of and information on the status of this state-of-the-art technology and describes the development of glass ionomers reinforced with carbon nanotubes possessing improved mechanical properties. The applications of carbon nanotubes in drug delivery and tissue engineering for healing infections and lesions of the oral cavity are also described. The review concludes with a summary of the current status and presents a vision of future applications of carbon nanotubes in the practice of dentistry.

Effect of smear layer deproteinization with HOCl solution on the dentin bonding of conventional and resin-modified glass-ionomer cements.

The effect of smear layer-deproteinizing pretreatment using hypochlorous acid (HOCl) on the micro-shear bond strengths (µSBS) of conventional and resin-modified glass-ionomer cements (GIC) to dentin was investigated and compared with demineralizing pretreatment with polyacrylic acid (PAA). Three GICs: Fuji IX GP Extra (restorative conventional GIC), GC Fuji II LC EM (restorative resin-modified GIC), and GC Fuji Luting EX (luting resin-modified GIC), were used. One hundred fifty human molars were divided into groups (n = 10) according to the cements and dentin pretreatments; no pretreatment (control), 10 s PAA pretreatment, and HOCl pretreatment for 5, 15, or 30 s. After 24 h, µSBS was tested and the data were statistically analyzed using a two-way ANOVA, followed by Tukey's post-hoc test. HOCl pretreatment significantly increased µSBS of conventional GIC compared to the control group. For resin-modified restorative GIC, 5 s HOCl deproteinization significantly increased µSBS, while longer application times did not. There was no significant difference between HOCl-pretreated and control groups of resin-modified luting GIC. PAA pretreatment increased the µSBS of all cements significantly. In conclusion, smear layer deproteinization with HOCl can enhance the dentin bonding of conventional GIC. However, the residual radicals may adversely affect the polymerization of resin-modified GICs.

Human pulp response to conventional and resin-modified glass ionomer cements applied in very deep cavities.

OBJECTIVES: This study assessed the human pulp response after adhesive restoration of cavities by indirect pulp capping with a conventional or a resin-modified glass ionomer cement. MATERIALS AND METHODS: Deep cavities prepared in 26 human premolars were lined with Riva Light Cure (Riva LC), Riva Self Cure (Riva SC), or Dycal, and then restored with composite resin. Four teeth were used as intact control. After time intervals of 7 or 30 days, the teeth were extracted, processed for histological evaluation of the pulp, and the remaining dentin thickness (RDT) between the cavity floor and the pulp was measured. RESULTS: At 7 days, a slight pulp inflammation associated with discrete tissue disorganization was observed in most of t the teeth lined with Riva LC and Riva SC. Moderate pulp inflammation occurred in one tooth lined with Riva LC. Bacteria were identified in one specimen of the same group that exhibited no pulp damage. At 30 days, slight pulp inflammation and discrete tissue disorganization persisted in two specimens treated with Riva LC, in which a thin layer of tertiary dentin was deposited. Mean RDTs ranged from 383.0 to 447.8 µm. CONCLUSIONS: Riva LC produced more damage to the pulp than Riva SC. However, the initial pulp damage decreased over time and after 30 days both GICs were labeled as biocompatible. CLINICAL RELEVANCE: In this study conducted with human teeth, the conventional and the resin-modified glass ionomer cements investigated were shown not to cause post-operative sensitivity or persistent pulp damage when applied as liners in very deep cavities, thereby indicating their biocompatibility.