An Evaluation of Experimental Calcium Ion-Leachable Nanocomposite Glass Ionomer Cements.

Glass ionomer cements (GICs) are among the main restorative dental materials used broadly in daily clinical practice. The incorporation of clay nanoparticles as reinforcing agents is one potential approach to improving GIC properties. This study aims to investigate whether the incorporation of calcium-modified clay (Ca-clay) nanoparticles in conventional GICs alters their structural characteristics, along with their physicochemical and mechanical properties. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were performed to assess the surface characterization of GIC nanocomposites, whereas a setting reaction was carried out via an attenuated total reflection Fourier transform infrared spectrometer (ATR-FTIR). A universal testing machine was used for compression tests, while calcium ion release was quantified using inductively coupled plasma optical emission spectrometry (ICP-OES). GIC composite groups reinforced with Ca-clay were found to release a fine amount of calcium ions (5.06-9.91 ppm), with the setting reaction being unaffected for low Ca-clay loadings. The median compressive strength of 3 wt% in the Ca-clay group (68.97 MPa) was nearly doubled compared to that of the control group (33.65 MPa). The incorporation of Ca-clay nanoparticles in GICs offers a promising alternative among dental restorative materials regarding their chemical and mechanical properties.

Synthesis and Characterization of Dental Nanocomposite Resins Reinforced with Dual Organomodified Silica/Clay Nanofiller Systems.

Quaternary ammonium (QA) compounds have been widely studied as potential disinfectants in dental restorative materials. The present work investigates whether the gradual displacement of nanosilica by QA-clay nanoparticles may have an impact on the physicochemical and mechanical properties of dental nanocomposite resins. For this purpose, Bis-GMA/TEGDMA-based composite resins were initially synthesized by incorporating 3-(trimethoxysilyl)propyl methacrylate (γ-MPS)-modified nanosilica/QA-clay nanoparticles at 60/0, 55/5, 50/10, 40/20, and 30/30 wt% filler loadings. Their structural characterization was performed by means of scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). The degree of double bond conversion (DC) over time and the polymerization shrinkage were determined with Fourier transform infrared spectroscopy (FTIR) and a linear variable displacement transducer (LVDT), respectively. Mechanical properties as well as water sorption and solubility parameters were also evaluated after storage of nanocomposites in water for 7 days at 37 °C. Spectral data revealed intercalated clay configurations along with areas characterized by silica-clay clusters for clay loadings up to 30 wt%. Furthermore, the insertion of 10 wt% QA-clay enhanced the auto-acceleration effect also sustaining the ultimate (DC), reduced the setting contraction and solubility, and, finally, yielded flexural modulus and strength very close to those of the control nanocomposite resin. The acquired results could herald the advanced design of dental restorative materials appropriate for contemporary clinical applications.

Cardiotoxicity of Chemical Substances: An Emerging Hazard Class.

(1) Background: Human health risks and hazards from chemical substances are well regulated internationally. However, cardiotoxicity, is not defined as a stand-alone hazard and therefore there are no defined criteria for the classification of substances as cardiotoxic. Identifying and regulating substances that cause cardiovascular adverse effects would undoubtedly strengthen the national health systems. (2) Methods: To overcome the aforementioned gap, a roadmap is proposed for identifying regulatory criteria from animal studies and endorse legislation in order to classify substances as cardiotoxic. The roadmap consists of: (i) the identification of the appropriate animal species and strains; (ii) the identification of the lines of scientific evidence (e.g., histopathological, biochemical and echocardiographic indices etc.) from animal studies with relevance to humans; (iii) the statistical analysis and meta-analysis for each line of scientific evidence after exposure to well-established cardiotoxicants to humans (e.g., anthracyclines) in order to identify threshold values or range of normal and/ or altered values due to exposure; (iv) validation of the above described lines of evidence in animals exposed to other alleged cardiotoxic substances (e.g., anabolic androgen steroids (AAS) and pesticides); (v) establishment of mechanisms of action based on information of either known or alleged cardiotoxicants; and (vi) introduction of novel indices and in silico methods. (3) Results: Preliminary results in rats indicate a clear distinction from normal values to values measured in rats exposed to anthracyclines regarding left ventricle (LV) fractional shortening (FS) and LV ejection fraction (EF). A distinctive pattern is similarly observed for Creatine Kinase-Myocardial Band isoenzyme (CK-MB) and cardiac tissue glutathione (GSH). These findings are encouraging and indicate that there is room for targeted research to this end, and that these specific indices and biochemical markers should be further investigated in order to be developed to regulatory criteria. (4) Conclusions: Further research should be conducted by both the scientific and regulatory community that aims to clearly define the cardiotoxicity hazard caused by chemicals and develop a full set of scientific criteria.

Children and Parents' Awareness Regarding Potential Hazards Derived from the Use of Chemical Products in Greece.

Over the last decades, human activities prompted the high production and widespread use of household chemical products, leading to daily exposure of humans to several chemicals. The objective of this study was to investigate the frequency of chemicals' use by children and parents in Greece and estimate the level of risk awareness and understanding among them. A total of 575 parents and children were asked to answer an anonymous, closed-ended, validated, and self-administered questionnaire. One-third of the children and almost half of the parents participating in the study believed that commonly used chemical products do not pose any risk to human health or to the environment, despite the product labelling. The majority of both children (61.8%) and parents (70.6%) were informed about product safety via the product labelling. Around 20% in both groups could not differentiate between systemic toxicity and acute lethal effects depicted by pictograms on the label and milder hazards, such as skin irritation. Moreover, the information on hazard and precautionary statements appearing on the label was very poorly perceived. Therefore, as both children and parents seem not to clearly identify the hazards and risks arising from the use of everyday chemical products, targeted awareness policies should be implemented to support the safe use of household products.

Cytotoxic Evaluation and Determination of Organic and Inorganic Eluates from Restorative Materials.

Over the last years, diverse commercial resin-based composites have dominated as dental filling materials. The purpose of the present study was to determine organic and inorganic eluates from five restorative materials using GC/MS and ICP-OES and to compare the effect on cell survival of human gingival fibroblasts of a conventional and a bioactive resin. Five commercially available restorative materials were employed for this study: ActivaTM Bioactive Restorative, ENA HRi, Enamel plus HRi Biofunction, Fuji II LC Capsule, and Fuji IX Capsule. Disks that were polymerized with a curing LED light or left to set were immersed in: 1 mL methanol or artificial saliva for GC/MS analysis, 5mL deionized water for ICP-OES, and 5mL of culture medium for cell viability. Cell viability was investigated with a modified staining sulforhodamine B assay.The following organic substances were detected: ACP, BHT, BPA, 1,4-BDDMA, CQ, DBP, DMABEE, HEMA, MCE, MeHQ, MOPA, MS, TMPTMA, and TPSb and the ions silicon, aluminum, calcium, sodium, and barium. Activa Bioactive Restorative was found to be biocompatible. Elution of organic substances depended on material's composition, the nature of the solvent and the storage time. Ions' release depended on material's composition and storage time. The newly introduced bioactive restorative was found to be more biocompatible.

Synthesis of Novel Dental Nanocomposite Resins by Incorporating Polymerizable, Quaternary Ammonium Silane-Modified Silica Nanoparticles.

Diverse approaches dealing with the reinforcement of dental composite resins with quaternary ammonium compounds (QAC) have been previously reported. This work aims to investigate the physicochemical and mechanical performance of dental resins containing silica nanofillers with novel QAC. Different types of quaternary ammonium silane compounds (QASiC) were initially synthesized and characterized with proton nuclear magnetic resonance (1H-NMR) and Fourier transform infrared (FTIR) spectroscopy. Silica nanoparticles were surface modified with the above QASiC and the structure of silanized products (S.QASiC) was confirmed by means of FTIR and thermogravimetric analysis. The obtained S.QASiC were then incorporated into methacrylate based dental resins. Scanning electron microscopy images revealed a satisfactory dispersion of silica nanoclusters for most of the synthesized nanocomposites. Curing kinetics disclosed a rise in both the autoacceleration effect and degree of conversion mainly induced by shorter QASiC molecules. Polymerization shrinkage was found to be influenced by the particular type of S.QASiC. The flexural modulus and strength of composites were increased by 74% and 19%, while their compressive strength enhancement reached up to 19% by adding 22 wt% S.QASiC nanoparticles. These findings might contribute to the proper design of multifunctional dental materials able to meet the contemporary challenges in clinical practice.

Microtensile Bond Strength Between Resin-Matrix CAD/CAM Ceramics and Resin Cement after Various Surface Modifications and Artificial Aging.

PURPOSE: To evaluate the effect of different surface modification methods on the microtensile bond strength (µTBS) of four resin-matrix CAD/CAM ceramics after artificial aging. MATERIALS AND METHODS: Specimens of four CAD/CAM materials (Shofu Block HC, Lava Ultimate, Brilliant Crios, and Vita Enamic) were prepared and divided into four groups. Each group received one of the following treatments: group 1 (INT): no surface modification; group 2: sandblasting with 29-µm Al2O3 particles (SB); group 3: hydrofluoric acid etching (9%) + silane (HF+Si); group 4: sandblasting with 30-µm particles of the CoJet system (CJ). The specimens of each group were luted together in pairs using resin cement (RelyX Ultimate). After one week of water storage (37°C), the sandwich specimens were sectioned into rectangular microspecimens and half of them were immediately subjected to µTBS testing, while the other half was tested after six months. Data were statistically analyzed using FFANOVA including the factors of material, treatment, and storage time, with α = 0.05. RESULTS: After one week, the lowest µTBS was observed for INT, while the highest was found for either mechanical (SB and CJ) or chemical (HF+Si) treatments (p < 0.05). After six months, a significant decrease in µTBS was observed depending on treatment (p < 0.05), while artificial aging significantly influenced the µTBS of all experimental groups (p < 0.05). During the two storage periods, the failure type was mainly interfacial and was associated with the type of surface modification. CONCLUSION: After artificial aging, the µTBS appeared to depend on srface modification, while the parameter "material" did not influence the results. Consequently, adhesive strategies should be oriented towards surface modification techniques.

Flow characteristics and alkalinity of novel bioceramic root canal sealers.

OBJECTIVE: This study aimed to examine the physical properties (pH and flow) of 2 novel bioceramic sealers. MATERIALS AND METHODS: The tested sealers were a calcium hydroxide sealer (Sealapex) and 2 bioceramic sealers (BioRoot RCS and TotalFill BC Sealer). Flow measurements were conducted according to ISO 6876/2012, with a press method of 0.05 mL of sealer. The pH of fresh samples was tested immediately after manipulation, while set samples were stored for 3 times the recommended setting time. The predetermined time intervals ranged from 3 minutes to 24 hours for fresh samples and from 10 minutes to 7 days and 4 weeks for the set samples. Analysis of variance was performed, with p = 0.05 considered indicating significance. RESULTS: The mean flow values were 26.99 mm for BioRoot, 28.19 for Sealapex, and 30.8 mm for TotalFill BC Sealer, satisfying the ISO standard. In the set samples, BioRoot RCS had higher pH values at 24 hours to 1 week after immersion in distilled water. At 2 weeks, both bioceramic sealers had similar pH values, greater than that of Sealapex. In the fresh samples, the bioceramic sealers had significantly higher initial pH values than Sealapex (p < 0.05). At 24 hours post-immersion, all sealers showed an alkaline pH, with the highest pH observed for TotalFill. CONCLUSIONS: The TotalFill BC Sealer demonstrated the highest flow. The bioceramic sealers initially presented higher alkaline activity than the polymeric calcium hydroxide sealer. However, at 3 and 4 weeks post-immersion, all sealers had similar pH values.

Safe use of chemicals and risk communication among dentists and dental students in Greece.

Use of chemicals, most often classified for intrinsic hazards, is rather common among dentists. To date, no data have been recorded in the European Union (EU) on dentists' awareness regarding the safe use of chemicals. In the EU regulatory framework, two Regulations with wide applications, namely Regulations (EC) 1907/2006 (REACH) and 1272/2008 (CLP), have been introduced to protect human health and the environment and clearly communicate hazards posed by chemicals to workers and consumers. The aim of this study was to assess the extent of comprehension of hazard communication of chemicals among Greek dentists. For this, a closed-ended, anonymous and validated questionnaire was initially distributed to a total of 300 Greek dentists, both professionals and university students, over a period of 4 months. The collected data from 240 final responders were subjected to statistical analysis (frequencies, percentages, chi-square (χ2) and significance (p < 0.05)). The vast majority (90%) of the interviewed dentists are not aware of the CLP. Main sources of information regarding chemical hazard and safe use was the supplier through direct communication (90%), while some dentists also consulted the product labels (39%) and the material safety data sheets (54%). Regarding hazard communication, the perceived information from the pictograms is confusing to the vast majority of the dentists (86%), especially for systemic hazards (carcinogenicity and/or reproductive toxicity). In addition, 88% of the professional dentists have not noticed any changes in the labelling of chemical products, which also shows the low input of labels to hazard communication. On the other hand, 90% of the responders always utilize personal protective equipment (PPE), although it is not clear whether this PPE is adequate. In conclusion, rising awareness campaigns are needed, in collaboration with universities and dental care professional associations, to inform dentists about the safe use of chemicals not only to ensure protection of their own health but also to contribute to environmental sustainability.

Organic Eluates Derived from Intermediate Restorative Dental Materials.

A great number of different types of materials have been used in dentistry as intermediate restoratives. Among them, new resin-based bases have been released in the dental market. The present study focuses on the identification of the organic eluates released from such materials and the study of their surface microstructure in combination with their corresponding elemental composition. For this purpose, the following materials were used:ACTIVA™BioACTIVE-BASE/LINER™, Ketac™Bond Glass Ionomer, SDR™ and Vitrebond™Light Cure Glass Ionomer Liner/Base. Methanolic leachates derived from polymerized materials were analyzed by means of gas chromatography-mass spectrometry (GC-MS). Scanning electron microscopy(SEM) was used for the surface monitoring of suitably prepared specimens. The GC-MS analysis revealed the elution of twenty different substances from the three resin-based materials, while none was eluted from the glass ionomer base. The SEM analysis for Vitrebond™ presented small pits, the one for Ketac™Bond presented elongated cracks, while no voids were present for ACTIVA™BioACTIVE-BASE/LINER™ and SDR™. Moreover, the resin matrix of some dental materials may inhibit elements' accumulation on the surface layers. Particularly, the detected organic eluents may be related to potential toxic effects.

Pit and fissure nanocomposite sealants reinforced with organically modified montmorillonite: A study of their mechanical properties, surface roughness and color stability.

The aim of the present work was to investigate the effect of the different organically modified nanoclays on clinically significant properties of new synthesized dental pit and fissure nanocomposite sealants. Their morphological characteristics were examined by means of X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). A universal testing machine was used to conduct the flexural and compression tests. Surface roughness measurements were taken by using a 3D-optical profilometer. Color changes after aging in black tea were determined by recording UV-visible spectra. XRD plots depicted possible structures governed by intercalated regions along with some "tactoids" nanoparticles. SEM images revealed a better dispersion for the methacrylated clay nanofiller. Flexural modulus and microhardness were found to be higher for sealants reinforced with such polymerizable nanoclays. These specific nanocomposites yielded smoother surfaces, as well as clinically accepted color changes even after 1 week aging in black tea.

Synthesis and Characterization of Dental Nanocomposite Resins Filled with Different Clay Nanoparticles.

Nanotechnology comprises a promising approach towards the update of dental materials.The present study focuses on the reinforcement ofdental nanocomposite resins with diverse organomodified montmorillonite (OMMT) nanofillers. The aim is to investigate whether the presence of functional groups in the chemical structure of the nanoclay organic modifier may virtually influence the physicochemical and/or the mechanical attitude of the dental resin nanocomposites. The structure and morphology of the prepared materials were investigated by means of wide angle X-ray diffraction and scanning electron microscopy analysis. Fourier transform infrared spectroscopy was used to determine the variation of the degree of conversion over time. Measurements of polymerization shrinkage and mechanical properties were conducted with a linear variable displacement transducer apparatus and a dynamometer, respectively. All the obtained nanocomposites revealed intercalated structures and most of them had an extensive filler distribution into the polymer matrix. Polymerization kinetics werefound to be influenced by the variance of the clay organomodifier, whilenanoclays with vinyl groups considerably increased the degree of conversion. Polymerization shrinkage was almost limited up to 50% by incorporating nanoclays. The absence of reactive groups in the OMMT structure may retain setting contraction atlow levels. An enhancement of the flexural modulus was observed, mainly by using clay nanoparticles decorated with methacrylated groups, along with a decrease in the flexural strength at a high filler loading. The overall best performance was found for the nanocomposites with OMMTs containing double bonds. The significance of the current work relies on providing novel information about chemical interactions phenomena between nanofillers and the organic matrix towards the improvement of dental restorative materials.

Investigation of the chemical profile and cytotoxicity evaluation of organic components eluted from pit and fissure sealants.

The aim of this study was to identify organic components eluted from five resin dental sealants using gas chromatography and mass spectrometry (GC/MS) after 1-day and 40-days storage and the effect of sealants on cell survival of cultured fibroblasts. Five resin materials were studied: BeautiSealant (SHOFU), Clinpro (3M/ESPE), Conseal F (SDI), Grandio Seal (VOCO) and Helioseal Clear (Ivoclar/Vivadent). The organic monomers detected were butylated hydroxytoluene (BHT), bis-phenol-A (BPA), camphoroquinone (CQ), diethylenglycoldimethacrylate (DEGDMA), 4N, N-dimethylaminobenzoic acid butylethoxyester (DMABEE), hydroxyethylmethcrylate (HEMA), hydroquinone monomethylether (MEHQ), triethylene glycol dimethacrylate (TEGDMA), tetrabutylammonium tetrafluoroborate (TBATFB), triphenylstibane (TPSb). The main monomer detected was TEGDMA, whereas BHT and DEGDMA were detected at lower concentrations. Higher monomer concentrations were detected after 40 days storage. The eluting chemical profiles of the tested materials differ qualitative and quantitative. For cytotoxicity evaluation, NIH/3T3 cells were exposed to eluates of sealants and cell viability was assessed by a quantitative technique at two observation periods. Decreased cell viability was observed. The cytotoxicity and the release of monomers from dental materials examined depends on the type of material and the observation time point. Resin-based dental materials have raised public concerns regarding possible adverse biological effects, thus it is essential to evaluate possible side effects for human health.

Influence of material and surface treatment on composite repair shear bond strength.

OBJECTIVES: The aim of this study is to investigate the influence of the composite material and surface treatment to the bond strength when repairing an aged composite surface with new composite. MATERIALS AND METHODS: One hundred and sixty resin blocks of methacrylate composite and silorane composite prepared and aged in artificial saliva for 6 months. Specimens treated either with a diamond bur (DB) or air abrasion (AA), conditioned with orthophosphoric acid (OA) or sodium hypochloride (SH) and repaired with methacrylate or silorane composite using the corresponding adhesive system. Repaired composites underwent thermocycling fatigue (×5000), and bond strength was measured at shear. RESULTS: Methacrylate achieved the highest bond strengths as repair material, in all combinations (26.54-55.56 MPa). Silorane only reached 8.12 MPa when repairing silorane treated with DB and OA. For all other treatment combinations repairing with silorane led to pretest failures. The most susceptible to repair composites/surface treatment combination is when repairing methacrylate treated with AA and SH and methacrylate composite (55.56 MPa). CONCLUSIONS: Silorane composites are not suitable to be used when repairing an old composite restoration. The repair material is the most critical factor, while aged surface treatment has only a minor influence to the shear bond strength.

Bonding of Composite to Base Materials: Effects of Adhesive Treatments on Base Surface Properties and Bond Strength.

PURPOSE: To evaluate the effects on the surface properties (morphology, roughness, microhardness, composition) and bond strength to composite of four types of base cements (Equia-Fil/EQF, Angelus white MTA/MTA, Biodentin/BDN and IRM/IRM) when treated with phosphoric acid etching (PAE) or two self-etch adhesives (Select One Prime & Bond and Clearfil S3 Bond). MATERIALS AND METHODS: Disk-shaped specimens were prepared and stored until complete setting. The surfaces before and after treatments were examined by stereomicroscopy, optical profilometry, ATR-FTIR, and LV-SEM/EDX. Interfacial bond strength with composite was evaluated under shear loading (SBS) using a conventional bonding resin (Heliobond) on silane treated (SIL) specimens as a reference. Failure mode was evaluated using stereomicroscopy. RESULTS: PAE induced compositional changes on MTA and BDN, forming a phosphate-rich surface layer, probably composed of Ca-P salts. Dissolution of the amorphous cement fractions was evident in all materials. SPB and CSB did not show remarkable changes apart from an increase in Si content on MTA. On all bases, PAE resulted in the highest values for most of the roughness parameters. SPB and CSB showed lower or equal average roughness (Sa) and percentage of additional surface area contributed by the texture (Sdr) compared to the control in MTA and EQL. In terms of SBS, the highest ß (Weibull shape parameter) in MPa were MTA-SIL = 5.79, BDN-PAE = 3.67, and MTA-PAE = 3.46, whereas the highest α (Weibull scale parameter) were EQF-CSB = 9.08, BDN-PAE = 5.13, and BDN-SIL = 4.67. Adhesive failures with less than 20% of the bonding area were encountered in IRM-PAE and SIL, EQF-CBS and MTA-SIL. CONCLUSION: Each base material requires a different procedure for optimal bonding with composite. Phosphoric acid etching and application of the conventional bonding resin Heliobond is the preferred procedure for composite bonding to MTA, BDN, IRM, but for composite bonding to CSB for EQF, the mild self-etch adhesive is preferable.

Cytotoxicity of a New Calcium Silicate Endodontic Sealer.

INTRODUCTION: Resin sealers with biocompatible and bioactive additives have been used in clinical practice. Recently, a calcium silicate root canal sealer was introduced under the name BioRoot RCS (Septodont, Saint Maur-des-Fossés, France). The aim of this study was to evaluate the effects of BioRoot RCS on cell survival and proliferation of cultured cells in parallel with an epoxy resin sealer with calcium phosphate and calcium oxide and a salicylate resin sealer with mineral trioxide aggregate filler. The tested hypothesis was that BioRoot RCS is significantly less cytotoxic than the other tested sealers. METHODS: The experiments were performed on NIH/3T3 cells (American Type Culture Collection, Manassas, VA) grown as monolayer cultures at 37°C in atmosphere containing 5% CO2 in air and 100% relative humidity. The sealers' extracts (24 hours and 1 week) were applied to cells at 1:1 and 1:2 dilutions. The effect was assessed by a modified sulforhodamine B staining assay in reference to controls after 24 and 72 hours of exposure. All experiments were performed at least twice in 6 replicates. Analysis of variance and post hoc comparison tests were used to evaluate the statistical significance of the results at a level of significance of P = .05. RESULTS: BioRoot RCS was significantly less cytotoxic than the other 2 sealers. MTA-Fillapex (Angelus, Londrina, Brazil) and SimpliSeal (Discuss Dental, LLC, Calver City, CA) exhibited a similar antiproliferative profile with no statistically significant differences in all settings. CONCLUSIONS: BioRoot RCS showed quite a positive biological behavior. Further investigation is needed in order to clarify the mechanism and the components that contribute to the beneficial results observed.

Color match of luting composites and try-in pastes: the impact on the final color of CAD/CAM lithium disilicate restorations.

AIM: Color matching of the restoration to the adjacent teeth can be difficult due to the translucency of the ceramic and the visual exposure of the polymerized resin cement through the ceramic material. The aim of this study was to identify color differences between try-in pastes and the corresponding luting resin composites. MATERIALS AND METHODS: The materials tested were Variolink Veneer, Variolink Try-In, Variolink Esthetic LC, and Variolink Esthetic Try-In. Blocks of IPS e.max CAD were bisected along the vertical axis, producing specimens of different thicknesses. The surfaces to be evaluated were finely polished with a metallographic machine using 6000 grit SiC paper. The IPS e.max CAD specimens cemented with resin cement or with the try-in pastes were superimposed on a resin composite specimen reproducing the tooth structure. Evaluation of the color differences between the try-in pastes and polymerized cements of the same shade was performed with a spectrophotometer and a visual evaluation by three observers. RESULTS: The measurements showed that for shades of Variolink Veneer and Variolink Esthetic LC resin cements and the corresponding try-in pastes there were significant color differences (ΔE > 2.23). Among the groups of different thicknesses, specimens of 0.5-mm thickness exhibited the highest ΔE values, while the specimens of 2-mm thickness exhibited the lowest. CONCLUSIONS: The present study suggests that dentists should not rely on try-in pastes for the final color evaluation because they do not perfectly match the color shade of the cement used for the final luting of ceramic restorations. The originality of this study was the interpretation of color differences utilizing both a scientific spectrophotometer and visual observation.

Management of bilateral invasive cervical resorption lesions in maxillary incisors using a novel calcium silicate-based cement: A case report.

Invasive cervical resorption is a pathologic process leading to progressive and usually destructive loss of tooth structure. The pathogenic mechanism is not completely understood and the diagnosis may be challenging. The aim of this article is to present an unusual case of bilateral presence of invasive cervical resorption lesions in maxillary central incisors and to discuss the treatment procedures using a novel repair material. The management of the present case was carried out in three phases. The first stage of the treatment aimed at curetting the active tissue from the resorption cavity and restoring the defect with the novel calcium silicate-based cement (Biodentine, Septodont). In the maxillary left central incisor it was not possible to remove the resorptive tissue without exposing the pulp, and therefore root canal treatment was performed. At the second phase, a full-thickness flap was raised in order to expose and repair the defect that was extending subgingivally. At the third phase teeth were restored with composite resin. The patient was kept under review and after a follow-up period of 2 years neither signs of periradicular lesion nor recurrence of resorption were observed. The teeth were asymptomatic, and restorations appeared to be in excellent condition. In conclusion, Biodentine seems to be a promising material for the treatment of invasive cervical resorption lesions.

Color match of resin composites to intact tooth structure.

INTRODUCTION: The optical properties of dental restorative materials have a dramatic effect on patient esthetics, which may be compromised by the poor blending effect of composites resins at the composite-tooth interface. OBJECTIVE: The objective of this study was to evaluate the color-matching ability and the blending effects of 3 different composite resins when restoring natural teeth. METHODS: Three commercially available composites and 60 central incisors were used for this experiment. Each tooth was sectioned horizontally at the level of the cementum-enamel junction, and the crown was then bisected along the long axis of the tooth. One half of each tooth was restored individually with composite resin, after matching with the corresponding tooth shade. The tooth color was evaluated preoperatively and postoperatively using an intraoral spectrophotometer and a scientific spectrophotometer. Color differences were then evaluated by the CIEDE2000 color difference formula. RESULTS: The results showed the existence of color differences between the intact and the restored sections of the teeth. However, these differences were considered acceptable, since the ΔΕ value ranged below 3.3. The ΔE, Δa and Δb parameters showed no statistically significant differences between the groups (p>0.05). CONCLUSIONS: The 3 composites tested were able to mimic natural teeth and produce acceptable restorations. However, the color of the resin composites needs to be evaluated over the long term, because it is subject to alterations in the oral environment over time.

Accidental ingestion of an air-water syringe tip during routine dental treatment: a case report.

Accidental ingestion of instruments or their components is a possible complication of dental treatment. Although in many cases the foreign object can pass through the gastrointestinal tract without any need for surgical intervention to retrieve it, sometimes such incidents can be life-threatening. This paper reports a case of accidental ingestion of an air-water syringe tip during routine dental treatment for which endoscopic retrieval was required. The present case highlights the need for dental professionals to be aware of the fact that dental equipment comprising multiple components may be associated with a risk of accidental detachment of a component and its ingestion or aspiration by a patient receiving treatment.