Restorative Biomaterials Research Articles

Interdisciplinary Delphi study by PROSEC North America: Recommendations on single indirect restorations made from ceramic and nonmetallic biomaterials for posterior teeth.

This article puts forward consensus recommendations from PROSEC North America regarding single indirect restorations made from ceramic and nonmetallic biomaterials in posterior teeth. The consensus process involved a multidisciplinary panel and three consensus workshops. A systematic literature review was conducted across five databases to gather evidence. The recommendations, informed by findings from systematic reviews and formulated based on a two-phase e-Delphi survey, emphasize a comprehensive treatment strategy that includes noninvasive measures alongside restorative interventions for managing dental caries and tooth wear. The recommendations advocate for selecting between direct and indirect restorations on a case-by-case basis, favoring inlays and onlays over crowns to align with minimally invasive dentistry principles. The recommendations highlight the critical role of selecting restorative biomaterials based on clinical performance, esthetic properties, and adherence to manufacturer guidelines. They emphasize the importance of precision in restorative procedures, including tooth preparation, impression taking, contamination control, and luting. Regular follow-up and maintenance tailored to individual patient needs are crucial for the longevity of ceramic and nonmetallic restorations. These PROSEC recommendations provide a framework for dental practitioners to deliver high-quality restorative care, advocating for personalized treatment planning and minimally invasive approaches to optimize oral health outcomes. The PROSEC North America recommendations highlight the importance of minimally invasive techniques in posterior tooth restorations using ceramic and non-metallic biomaterials. These principles prioritize tooth structure conservation and personalized treatment planning, essential for enhancing clinical outcomes and long-term oral health.

Unprecedented Benzoquinone Motifs Reveal Post-Oligomerizational Modification of Proanthocyanidins.

Proanthocyanidins (PACs) are complex flavan-3-ol polymers with stunning chemical complexity due to oxygenation patterns, oxidative phenolic ring linkages, and intricate stereochemistry of their heterocycles and inter-flavan linkages. Being promising candidates for dental restorative biomaterials, trace analysis of dentin bioactive cinnamon PACs now yielded novel trimeric (1 and 2) and tetrameric (3) PACs with unprecedented o- and p-benzoquinone motifs (benzoquinonoid PACs). Challenges in structural characterization, especially their absolute configuration, prompted the development of a new synthetic-analytical approach involving comprehensive spectroscopy, including NMR with quantum mechanics-driven 1H iterative functionalized spin analysis (HifSA) plus experimental and computational electronic circular dichroism (ECD). Vital stereochemical information was garnered from synthesizing 4-(2,5-benzoquinone)flavan-3-ols and a truncated analogue of trimer 2 as ECD models. Discovery of the first natural benzoquinonoid PACs provides new evidence to the experimentally elusive PAC biosynthesis as their formation requires two oxidative post-oligomerizational modifications (POMs) that are distinct and occur downstream from both quinone-methide-driven oligomerization and A-type linkage formation. While Nature is known to achieve structural diversity of many major compound classes by POMs, this is the first indication of PACs also following this common theme.

The In-Vitro Effect of Silver and Zinc Oxide Nanoparticles on Fluoride Release and Microhardness of a Resin-Modified Glass Ionomer Cement

Reinforcement of nanoparticles into existing restorative biomaterials in dentistry is an area of interest. The aim of the current investigation was to incorporate silver nanoparticles (SNP) and zinc oxide nanoparticles (ZnONP) into a commercially available resin-modified glass ionomer cement (RMGIC). Their effects on the fluoride (F-) release from RMGIC were also investigated over a period of 14-days. Nanoparticles were incorporated at a loading concentration of 5 wt%, either individually or in a combination of both. Scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FTIR), Nanocomputerized tomography (NanoCT), and the Vickers microhardness tester were used to examine the specimens. The fluoride release was analyzed by high performance liquid chromatography (HPLC). Data were analysed using ANOVA and Tukey’s test. RMGIC containing 5% ZnONP and 5% SNP + 5% ZnONP showed significant alterations in the surface ultrastructure with pores being evident in the surface. Fluoride release in parts per million (ppm) was highest in the 5% SNP and 5% ZnO-NP incorporated RMGIC compared to the control group and 5% SNP-incorporated RMGIC. RMGIC, as well as change in color observed in the 5% SNP incorporated RMGIC.

Biomimetic Approach in Tooth Conservation and Fracture Resistance: A Short Descriptive Review of Current Biomaterials and Techniques

Background: New concepts such as biomimetic dentistry, minimally invasive approach, and the understanding of tooth biomechanics have changed the paradigm on how teeth need to be restored. The emergence of new biomaterials has allowed to improve bonding capacity, as well as the ability to reduce loading stress transmitted to the remaining tooth structure, making it possible to extend the life of a restoration and give the compromised tooth a second chance. To date, several studies have demonstrated the fracture resistance under uniaxial loading of restored Class II mesial-occlusal-distal (MOD) dental cavities in posterior teeth using different restorative biomaterials; however, many of those materials have not yet been compared with each other regarding fracture resistance. Objectives: A literature review was undertaken to revise current research focusing on the fracture resistance of MOD cavity preparations restored with different filling techniques, including microhybrid and nanohybrid composite resin, short discontinuous fiberglass reinforced composite resin, long continuous polyethylene fiber, fiberglass reinforced net, and the combination of these materials. Conclusion: This literature review offers information regarding currently used restorative biomaterials’ fracture resistance in restored MOD teeth. Most studies were conducted in vitro, demonstrating that fracture resistance under uniaxial load was higher in MOD cavity preparations restored with a combination of polyethylene fibers and composite resin (nanohybrid), followed by a combination of fiberglass and composite resin (nanohybrid). The reviewed information also revealed that the use of composite resin as a single material has the lowest fracture resistance and the highest percentage of catastrophic failures. Given the limited information regarding the combination of these biomaterials in a clinical setting it is suggested to perform controlled clinical trials by using the proposed combinations to demonstrate their clinical relevance and success ratio. Nonetheless, initial data suggests that a biomimetic restorative approach using biomaterials that connect and replace the missing tooth structure and redistribute biologically the loading stress may have a positive impact in terms of tooth preservation in MOD cavities.

Interdisciplinary approach for complex esthetic periodontal or prosthodontic treatment: a case report

Patients with a complex periodontal/restorative esthetic condition can only be successfully treated with an interdisciplinary approach. This report presents case managed with varying levels of periodontal and prosthodontic coordination of care. A 48-year-old female patient with no medical conditions, presented chiefly to enhance her dental esthetics and eliminate the central diastema. There was also gingival asymmetry and altered passive eruption (APE). High frenal attachment was also noticed in relation the central diastema space. The depigmentation, gingivectomy, and gingivoplasy procedures were planned accordingly. After 3 months of periodontal healing, the patient returned for the final porcelain veneer restorations limiting to the upper anterior incisors. The treatment of the complex periodontal/prosthetic esthetic patient can be achieved with an interdisciplinary approach. Such a dental rehabilitation should be beginning by a comprehensive esthetic examination. Then an accurate diagnosis, prognosis evaluation, and treatment planning have to be identified. In addition, the utilization of an advanced surgical and restorative biomaterials will ensure the best result with patient satisfaction.

In vitro Study on Mechanical Properties of Polyacid-modified Composite Resins (Compomers)

At the beginning of the 90 s on the market of dental restoration materials appeared compomers, polyacid modified composite resins (PMC). The term compomer suggests a combination of glass-ionomer and composite technology. This has led to confusion about how it relates to dental structures. The properties and adhesion of compomers to dental structures suggest a closer connection with composites than with glass ionomers. They do not have direct chemical adhesion to any tooth structure it adheres similar to the composites through a separate binding agent. However, their proximity to composites does not make them substitutes of composites. Compomers are a versatile class of dental restorative biomaterials, whose clinical benefits are particularly useful in pediatric dentistry.

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

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

The effect of dental caries and restorative biomaterials on IL-1 β and TNF-α levels in the gingival crevicular fluid

Background/Aim. In the spirit of personalized medicine, determining caries biomarkers in the saliva and gingival crevicular fluid (GCF) attracts great attention in the current dental re-search. The concentration of GCF cytokines is illustrative in depicting the processes in tooth structures. Their relevance must be inspected with aspects of tooth position and caries lesion level. Different impacts of dental restoration materials on GCF IL-1? and TNF-? could be used as a parameter for estimating local inflammation. This paper aimed to estimate the concentrations of the proinflammatory cytokines (IL-1? and TNF-?) in the GCF and to correlate them with caries extension, tooth position, and different restorative biomaterials. Methods. GCF samples were collected from 90 periodontally healthy patients demonstrating at least one tooth with proximal caries and one intact tooth, at the baseline, 7 and 30-days post-treatment. The biomarkers? profile was investigated in relation to different levels of caries extension (superficial, pulpitis, gangrenous, root affection), defect size, and restorative biomaterial. Results. Before therapy, caries level was significantly associated with GCF IL-1? concentration, demonstrating the lowest level in gangrenous (C4) and superficial caries (C2). Thirty days after therapy, root affection (C5) was characterized by the highest IL-1? concentration. Different dental fillings showed various GCF cytokine changes. CPC induced a significant IL-1? increase in more than 70% of treated patients. Caries lesion size was insignificantly associated with GCF levels of these proinflammatory cytokines, where larger defects were followed by an average cytokine increase. Considering the tooth position be-fore therapy, IL-1? had the highest level in GCF samples from caries-affected canines and second molars, while TNF-? showed the highest levels from canines GCF. Dental restoration induced cytokine increase in canines (IL-1? and TNF-?), 1st and 2nd molars GCF (IL-1?). Conclusion. Inflammation intensity of tooth structures was directly reflected in IL-1? and TNF-? concentrations. Dental restoration significantly affects IL-1? and TNF-? levels, depending on the used dental filling-type material. The profile of these cytokines varied in GCF samples of the tooth with different anatomical positions, where canines and molars demonstrated the highest level. An increase of these proinflammatory cytokines in the absence of any symptomatic manifestation of the inflammatory response can be considered as a possible tooth reparation parameter.

Biomimetic Aspects of Restorative Dentistry Biomaterials.

Biomimetic has emerged as a multi-disciplinary science in several biomedical subjects in recent decades, including biomaterials and dentistry. In restorative dentistry, biomimetic approaches have been applied for a range of applications, such as restoring tooth defects using bioinspired peptides to achieve remineralization, bioactive and biomimetic biomaterials, and tissue engineering for regeneration. Advancements in the modern adhesive restorative materials, understanding of biomaterial–tissue interaction at the nano and microscale further enhanced the restorative materials’ properties (such as color, morphology, and strength) to mimic natural teeth. In addition, the tissue-engineering approaches resulted in regeneration of lost or damaged dental tissues mimicking their natural counterpart. The aim of the present article is to review various biomimetic approaches used to replace lost or damaged dental tissues using restorative biomaterials and tissue-engineering techniques. In addition, tooth structure, and various biomimetic properties of dental restorative materials and tissue-engineering scaffold materials, are discussed.

Effect of Common Daily Acidic Beverages on the Surface Roughness of Glass Ionomer-Based Dental Restorative Biomaterials

The aim of this study was to compare the effect of different immersion protocols into various acidic media on the surface roughness of various glass ionomer-based dental restorative materials in vitro. The total number of 200 specimens were prepared from 5 different restorative material groups. Ten specimens from each group were then immersed into one of the tested beverages including; Coca-Cola, Iced-Tea, orange juice and distilled water (control). All specimens were kept in oven at 37°C for designated time periods of 1 day, 1 week, 1 month, 3 months, 6 months and 1 year and solutions were renewed weekly. Surface roughness measurements were performed at baseline and after each immersion period. The surface roughness of all glass ionomer-based restorative materials were affected by immersion with acidic media to a degree. For Glass Carbomer, there were steady increases in surface roughness in Ice Tea and orange juice (p 0.05). When compared with distilled water, surface roughness of Chemfil Rock had increased significantly in coke and orange juice (p < 0.05). Surface roughness values of F2000 had increased significantly in coke and ice tea compared with distilled water (p < 0.05). For Dyract XP, only significant increase was found in coke compared with distilled water (p < 0.05). In conclusion, compomers were determined as the most robust materials comparing the surface roughness of the other glass ionomer based materials particularly used in pediatric dentistry. The surface degradation following immersion with acidic media is a multifactorial process, not only the pH and composition of the acidic environment, but also the type and composition of the exposed restorative material have influence on this process.

Low-Pressure Plasma Sterilization for Test Specimens to be Worn on Splints in the Oral Cavity

Bacterial biofilms adhere to all oral surfaces and may alter or degrade them. For investigations of the oral biofilm, growing on new restorative dental biomaterials, sterilized dental enamel surfaces as natural, control, and reference materials are used. A novel method for disinfection and sterilization of surfaces is low-pressure plasma (LPP) sterilization, which is a nondestructive and nontoxic technology. The roughness of the dental enamel surface was determined before and after LPP sterilization. Enamel discs were placed in dental splints and worn for five days in vivo. Oral biofilm was fixed for scanning electron microscopy (SEM). Biofilms growing in vitro were characterized microbiologically before and after sterilization and examined by confocal laser scanning microscopy (CLSM). Microbiology demonstrated that various bacterial strains were present in the biofilms. SEM showed multiple layers of densely packed bacteria, and CLSM demonstrated that the biofilm contained live and dead bacteria. After LPP sterilization, no biofilm could be detected, and the enamel surface remained unaltered. It may be concluded that LPP sterilization is an effective, nondestructive method for disinfection of enamel before application in the oral cavity. LPP sterilization may be suitable for sterilization of dental materials without altering their surfaces.

In Vitro Caries Models for the Assessment of Novel Restorative Materials.

Due to the high failure rates of traditional dental restorations, there is an ongoing effort to develop modified and new restorative biomaterials in dentistry. Being the most commonly used restorative material, most of these efforts primarily aim to improve dental composite. Generally, the main objective of such modifications is to enhance the restorative physical and antimicrobial properties in order to limit micro-leakage and inhibit bacterial biofilm cultivation. Herein, we describe the process of designing a simple in vitro model to assess the physical and antimicrobial properties of novel restorative materials in addition to evaluating their effect on the fragile balance between enamel de- and remineralization.

Applications of inflammation-derived gingival stem cells for testing the biocompatibility of dental restorative biomaterials

BackgroundNormal or inflamed gingival tissues are regarded as a source of mesenchymal stem cells (MSCs) abundant and easily accessible through minimally invasive dental procedures. Due to the proximity of dental resin composites to gingival tissues and to the possible local cytotoxic effect of the eluted components, gingiva-derived MSCs could be used to investigate the biocompatibility of dental biomaterials. PurposeThe present research aimed to isolate (MSCs) from inflamed and normal gingiva, to fully characterize them and to observe their behavior in relation with some commercial resin composite materials and one experimental material. Material and methodsFollowing their isolation, putative MSCs from both gingival sources were grown under the same culture conditions and characterized by immunophenotyping of cell surface antigens by flow-cytometry and transcription factors by immunocytochemical staining. Moreover, stemness gene expression was evaluated by RT-PCR analysis. Multipotent mesenchymal differentiation potential was investigated. Osteogenic and neurogenic differentiated cells were highlighted by immunocytochemical staining, chondrogenic cells by cytochemical staining, and adipocytes by cytochemical staining and spectrophotometry, respectively. Resin composite cytotoxicity was evaluated by cell membrane fluorescent labeling with PKH 26 and MTT assay. The results of PKH labeling were statistically analysed using two-way RM ANOVA with Bonferroni post-tests. For MTT assay, two-way RM ANOVA with Bonferroni post-tests and unpaired t test with Welch’s correction were used. ResultsA similar expression pattern of surface markers was observed. The cells were positive for CD105, CD73, CD90, CD49e, CD29, CD44 and CD166 and negative for CD45, CD34, CD14, CD79, HLA-DR and CD117 indicating a mesenchymal stem cell phenotype. The qRT-PCR analysis revealed a low gene expression for NOG, BMP4 and Oct3/4 and an increased expression for Nanog in both cells lines. Immunocytochemical analysis highlighted a more intense protein expression for Nanog, Oct3/4 and Sox-2 in MSCs derived from normal gingiva than from inflamed gingiva. Multipotent differentiation capacity of MSCs isolated from both sources was highlighted. The tested materials had no hazardous effect on MSCs as the two cell lines developed well onto resin composite substrates. Cell counting revealed some significant differences in the number of PKH-labeled MSCs at some experimental moments. Also, some differences in cell viability were recorded indicating better developmental conditions offered by some of the tested biomaterials. ConclusionsThe experimental resin composite behaved like the most biocompatible commercial material. Inflamed gingiva-derived MSCs retain their stem cell properties and could be used as a valuable cell line for testing dental biomaterials.

The Dental Architect

The systematic and simple replacement of missing teeth without radical manipulation of existing sound structure— over preparation, utilizing scaffolding, or a matrix the “Winged Pontic” of prefabricated filled composite resin, may correctly be characterized as bio-synthetic tissue engineering. A new conversation regarding one of the direction of prosthetic dentistry for the 21st Century is offered in Stephan C. Bayne’s review of the state of the art for restorative biomaterials titled Dental Biomaterials: Where Are We and Where Are We Going? The non-invasive, uncomplicated, artistically and professionally rewarding “Winged Pontic” approach is one such arts, synthetic tissue engineering. The case report offered in this manuscript demonstrates the concept of direct and immediate tooth replacement in a step by step methodology that may easily be adapted by the dental surgeon. Fiber reinforcement is unnecessary based upon 25 years of research since it is cumbersome, ineffectual, and disruptive to the filled composite resin matrix. In any instance, the “Winged Pontic” fixed prosthesis may be viewed as a short term, medium term, or definitive restoration. It may also serve as a pediatric tooth space maintainer or as a implant stabilization prosthesis during osseointegration of dental implants by hollowing out the tissue side core of the “Winged Pontic” and placing it over the healing abutment of the dental implant

Quantification of Staphylococcus aureus adhesion forces on various dental restorative materials using atomic force microscopy

In the oral cavity dental restorative biomaterials can act as a reservoir for infection with opportunistic Staphylococcus aureus pathogen, which can lead to the occurrence of secondary caries and treatment failures. Our aim was to evaluate the adhesion forces by S. aureus on four dental restorative biomaterials and to correlate this finding to differences in specific surface characteristics. Additionally, the influence of salivary conditioning films in exerted adhesion forces was investigated. The substrate hydrophobicity was measured by goniometer and the surface free energy was calculated using the equilibrium advancing contact angle values of water, formamide, and diiodomethane on the tested surfaces. The surface roughness was determined using atomic force microscope (AFM). Additionally, cell force spectroscopy was achieved to quantify the forces that drive cell-substrate interactions. S. aureus bacterium exerted a considerable adhesion forces on various dental restorative materials, which decreased in the presence of saliva conditioning film. The influence of the surface roughness and free energy in initial adhesion appears to be more important than the effect of hydrophobicity, either in presence or absence of saliva coating. Hence, control of surface properties of dental restorative biomaterials is of crucial importance in preventing the attachment and subsequent the biofilm formation.

Impact Behavior of Three Notched All-Ceramic Restorations after Soaking in Artificial Saliva.

Biomechanics play a critical role in influencing the clinical applications of all-ceramic dental restorations. The restorative biomaterials have to demonstrate mechanical durability in the oral environment because they are always exposed to a variety of oral environments. This study was designed to evaluate the effect of soaking time, notch and saliva pH values on the impact energy of three commonly used all-ceramic materials for CAD/CAM. The leucite-reinforced glass ceramic (ProCAD), lithium disilicate glass ceramic (IPS e.max CAD) and zirconia-based ceramic materials (IPS e.max ZirCAD) were used. The experimental results indicated that the impact energy of ProCAD decreased with an increase in soaking time, but not for IPS e.max CAD and IPS e.max ZirCAD. The impact energy of the zirconia system was higher than leucite-reinforced and lithium disilicate-based ceramic systems. When subjected to preformed 0.5 mm U-shape notch on the bar specimen of 3 mm thick, the impact energy of the all-ceramic restorations revealed a markedly reduction of about 80%–90%, almost irrespective of dental compositions, which indicated the effect of flaw to a great degree. No statistically significant influence (p > 0.05) of pH values (4, 7 and 9) on impact energy was found for each group. It is concluded that the no matter which all-ceramic materials were used, it was appreciably sensitive to the presence of notches. The ceramic composition and microstructure have been shown to affect mechanical durability.

Biomaterials in Relation to Dentistry.

Dental caries remains a challenge in the improvement of oral health. It is the most common and widespread biofilm-dependent oral disease, resulting in the destruction of tooth structure by the acidic attack from cariogenic bacteria. The tooth is a heavily mineralised tissue, and both enamel and dentine can undergo demineralisation due to trauma or dietary conditions. The adult population worldwide affected by dental caries is enormous and despite significant advances in caries prevention and tooth restoration, treatments continue to pose a substantial burden to healthcare. Biomaterials play a vital role in the restoration of the diseased or damaged tooth structure and, despite providing reasonable outcomes, there are some concerns with clinical performance. Amalgam, the silver grey biomaterial that has been widely used as a restorative material in dentistry, is currently in throes of being phased out, especially with the Minimata convention and treaty being signed by a number of countries (January 2013; http://mercuryconvention.org/Convention/) that aims to control the anthropogenic release of mercury in the environment, which naturally impacts the use of amalgam, where mercury is a component. Thus, the development of alternative restoratives and restoration methods that are inexpensive, can be used under different climatic conditions, withstand storage and allow easy handling, the main prerequisites of dental biomaterials, is important. The potential for using biologically engineered tissue and consequent research to replace damaged tissues has also seen a quantum leap in the last decade. Ongoing research in regenerative treatments in dentistry includes alveolar ridge augmentation, bone tissue engineering and periodontal ligament replacement, and a future aim is bioengineering of the whole tooth. Research towards developing bioengineered teeth is well underway and identification of adult stem cell sources to make this a viable treatment is advancing; however, this topic is not in the scope of this chapter. Whilst research focuses on many different aspects, operative dentistry involves the wide use of restorative biomaterials; thus, the development of smart biomaterials to suit the current climes of minimally invasive dentistry is important. The concept of minimally invasive dentistry primarily promotes preservation of the natural tissue, and, thus, the prevention of disease or the advancement of procedures that allow early detection and interception of its progress with minimal tissue loss are of significance. This chapter presents, in brief, the current state of the art of direct restorative biomaterials and their role and future in the field of dentistry. Modern dental practice is highly reliant on the selection of appropriate materials for optimum function and benefit to the patient. Dentistry, perhaps, has the unique distinction of using the widest variety of materials, ranging from polymers, metals, ceramics, inorganic salts to composite materials. So far, aesthetics of restorative materials and their ability to perform in the harsh oral environment without undergoing changes in dimension and stability has been the major focus of materials used in dentistry. Despite advances in tissue engineering and regeneration in the field of regenerative medicine, this concept has found relatively limited application for enamel and dentine due to their limited ability to remodel, but research related to biomimetic approaches for the modification of dentine is a significant step.

Autophagy in resin monomer-initiated toxicity of dental mesenchymal cells: a novel therapeutic target of N-acetyl cysteine.

Dental restorative biomaterials are commonly used to restore the teeth impaired by caries, erosion, or fracture. Resin monomers released from polymerized restorative composite materials could disturb cell viability and cause toxicity of oral eukaryotic cells, which remains a medical challenge. However, the intracellular processes or underlying mechanisms of resin monomer-mediated toxicity and the potential preventive/therapeutic strategy are still far from clear. The present study aimed to determine the role of autophagy in resin monomer triethylene glycol dimethacrylate (TEGDMA)-induced cytotoxicity and explore autophagy as a potential therapeutic target of anti-oxidant N-acetyl cysteine (NAC) in vitro and ex vivo. The results showed that TEGDMA exposure resulted in several specific features of autophagy in human dental mesenchymal cells (DMCs), including the formation of acidic vesicular organelles, appearance of autophagic vacuoles, and LC3-II accumulation. By pharmacological and genetic approaches, the inhibition of autophagy significantly prevented TEGDMA-induced apoptosis in DMCs. Moreover, the autophagy activated by TEGDMA occurred via the AMPK/mTOR pathway, which could be abrogated by NAC pretreatment. More importantly, the tooth slice organ culture model provided further evidence of autophagy involvement in TEGDMA-triggered dental mesenchymal tissue toxicity and as a therapeutic target of NAC ex vivo. Our findings provide novel insights into the mechanisms of resin monomer-mediated toxicity and highlight autophagy as a promising therapeutic target of NAC for improving dental restorative biomaterials that enable dental tissue protection.

Nanotechnology in Adhesive Restorative Biomaterials

Nanotechnology in Adhesive Restorative Biomaterials

Role of physical properties of dental restorative biomaterials in criminalistics

Role of physical properties of dental restorative biomaterials in criminalistics Cristiana Palmela Pereira,1&ndash;4 Jo&atilde;o Franco Costa,5 Jorge Costa Santos,6,7 Maria Cristina de Mendon&ccedil;a6,7 1Legal Medicine and Forensic Sciences, Faculty of Medicine, University of Lisbon, Lisbon, 2Departments of Pharmacology and Therapeutic and Dental Morphology, Faculty of Dental Medicine, University of Lisbon, Lisbon, 3Integrate Research from the Research Centre of Statistics and Applications of the University of Lisbon, Lisbon, 4South Branch of the Portuguese National Institute of Legal Medicine and Forensic Sciences, Lisbon, 5Judicial Police, Lisbon, 6Medical Legal Doctors, South Branch of the Portuguese National Institute of Legal Medicine and Forensic Sciences, Lisbon, 7Faculty of Medicine, University of Lisbon, Lisbon, Portugal Abstract: The body of an 89-year-old woman was discovered at home by a member of her family. Only part of the body, the legs, were found intact without burn damage. The rest of the body was burned to ashes without the possibility to identify the cadaver. Forensic Dentistry had two main goals to resolve in this forensic pathology casework, and they were: 1) establish the identification of the cadaver; and 2) estimate the temperature and the direction of the fire by the analysis and interpretation of the skeletal intraoral dental materials altered by thermal processes. This case study manuscript focuses only on the second objective. The effects of fire on teeth are influenced by the temperature applied and by its duration. Additionally, adjacent tissues as well as temperature alterations caused by substances used to quench the fire have been shown to affect the thermal impact on teeth and their restoration. Bodies may be subjected to various temperatures, depending on the origin of the fire and the conditions that promote continuation of the blaze. Fire effects on certain dental materials can indicate the direction and the temperature of a fire. This is based on the physical, mechanical, and chemical changes of different dental materials resulting from high temperatures. The distinct properties of various dental materials, well defined, can influence and predict their performance under different degrees of fire. In this case study, the cadaver had two main groups of dental materials: metal alloys and polymers. The importance of the detailed degree of predictability of fire performance data from thermal decomposition data should not be underestimated; polymers cannot burn if they do not break down and metal alloys cannot burn if the melting point is not reached, independent of the variable time of the fire. Keywords: fire investigation, forensic dentistry, dental materials properties