Elution of substances from a silorane-based dental composite

Kopperud HM, Schmidt M, Kleven IS. Elution of substances from a silorane-based dental composite. Eur J Oral Sci 2010; 118: 100–102. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci
Previous studies have shown that residual monomers, initiators, and additives are eluted from methacrylate-based dental composite materials. Recently, a composite material (Filtek Silorane), based on a new resin chemistry, was introduced. The purpose of this study was to investigate substances eluted from Filtek Silorane in water and ethanol. Polymerized specimen discs of the material were immersed in either distilled water or 75 vol% ethanol at 37°C, and the solutions were analyzed using liquid chromatography-mass spectrometry after 1, 4, 24, and 72 h eluting time. No substances were found to leach from Filtek Silorane in water, whereas silorane monomers and an initiator component were eluted from the material into the ethanol solution.     

BisGMA/TEGDMA dental composite containing high aspect-ratio hydroxyapatite nanofibers

Objectives

The objectives of this study are to investigate the properties of high aspect-ratio hydroxyapatite (HAP) nanofibers and the reinforcing effect of such fibers on bisphenol A glycidyl methacrylate (BisGMA)/triethylene glycol dimethacrylate (TEGDMA) dental resins (without silica microparticle filler) and dental composites (with silica microparticle filler) with various mass fractions (loading rates).

Methods

HAP nanofibers were synthesized using a wet-chemical method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and thermal gravimetric analysis (TGA). Biaxial flexural strength (BFS) of the HAP nanofibers reinforced dental resins without any microsized filler and dental composites with silica microparticle filler was tested and analysis of variance (ANOVA) was used for the statistically analysis of acquired data. The morphology of fracture surface of tested dental composite samples was examined by SEM.

Results

The HAP nanofibers with aspect-ratios of 600 to 800 can be successfully fabricated with a simple wet-chemical method in aqueous solution. Impregnation of small mass fractions of the HAP nanofibers (5 wt% or 10 wt%) into the BisGMA/TEGDMA dental resins or impregnation of small mass fractions of the HAP nanofibers (2 wt% or 3 wt%) into the dental composites can substantially improve the biaxial flexural strength of the resulting dental resins and composites. A percolation threshold of HAP nanofibers, beyond which more nanofibers will no longer further increase the mechanical properties of dental composites containing HAP nanofibers, was observed for the dental composites with or without silica microparticle filler. Our mechanical testing and fractographic analysis indicated that the relatively good dispersion of HAP nanofibers at low mass fraction is the key reason for the significantly improved biaxial flexural strength, while higher mass fraction of HAP nanofibers tends to lead to bundles that cannot effectively reinforce the dental resins or composites and may even serve as defects and thus degrade the resulting dental resin and composite mechanical properties.

Significance

The incorporation of small mass fraction of HAP nanofibers with good dispersion can improve the mechanical property of dental resins and dental composites.     

Effect of resin matrix composition on the translucency of experimental dental composite resins

ObjectivesThe purpose of this study was to investigate the effect of the resin matrix composition on the translucency of experimental dental composite resins.MethodsThree types of unfilled resin matrices (TEGDMA-, UDMA- and BisGMA-based) were formulated and light cured. In addition, six different experimental dental composite resins with constant filler loading but varying in the type of monomer and the content of BisGMA were fabricated. Discs of each test material with 15.5 mm diameter and 1.0 mm thickness were prepared (N = 3) and light cured. Total and diffuse transmittance values for each sample were measured using a UV/VIS spectrophotometer with the range of readings from 380 to 700 nm. Difference in color was measured using the CIE Lab system.ResultsStatistical analysis by one-way ANOVA followed by Tukey's test showed that there was no statistically significant difference in transmittance values between the three unfilled resins. However, with the addition of filler, BisGMA-containing composite resins showed significantly higher transmittance values than the UDMA- and TEGDMA-based composite resins. Regression analysis revealed that there was a linear correlation between the percentage of BisGMA in the resin matrix and the total and diffuse translucency.SignificanceThe amount of BisGMA used in the resin matrix has a significant effect on the translucency of silica filler-containing dental composite resins.     

Long-term elution of monomers from resin-based dental composites

Objective

To bridge the gap between the current alarming literature on resin-based dental materials and the limited clinical observations, more precise knowledge on the actual quantity of released compounds should be acquired. The objective of this study was to quantify the long-term elution of various compounds from resin-based dental composites during one year.

Elution parameters and HPLC-detection of single components from resin composite

The toxic effects of mercury derived from amalgam fillings have been a focus of controversy in Germany during the last 25 years. As alternatives to amalgam, composites are used widely to restore anterior and posterior permanent teeth. This study quantifies the amount of TEGDMA and methacrylic acid that can be derived from a polymerized commercial hybrid composite material. Different specimens were made with different curing methods with and without an oxygen inhibition layer. To simulate the removal of composite fillings, some samples were pulverized. The specimens were eluted in distilled water at 37^°C for different time intervals. To check the influence of acid conditions, pulverized material was incubated in 6 M HCl. The separation of the eluted chemical resin components was done by HPLC. A defined mixture of pure components was used as an external standard for the identification and quantification of the eluted components. The results focus on the release of triethylenglycoldimethacrylate (TEGDMA) and methacrylic acid. Concerning the different incubation methods, the results showed higher TEGDMA elution with oxygen inhibited surface layer and with the pulverized samples. Within acid conditions, the amount of TEGDMA found was low, but the amount of methacrylic acid increased. Small resin monomers like TEGDMA are primarily eluted from composite in aqueous solutions. Within acid conditions a hydrolytic disintegration of the ester bonding of the monomers could be observed. Methacrylic acid – a substance with allergenic potential – could be detected. Received: 27 May 1999 / Accepted: 23 August 1999     

Optical characterization of bisphenol-A-glycidyldimethacrylate–triethyleneglycoldimethacrylate (BisGMA/TEGDMA) monomers and copolymer

OBJECTIVE: The fundamental optical characteristics of dental polymers as a function of curing time are exiguously reported in the literature. In this work the refractive index [1] and the extinction coefficient [2] of bisphenol-A-glycidyldimethacrylate-triethyleneglycoldimethacrylate (BisGMA/TEGDMA)-based polymers of different volume fractions have been studied as a function of the curing time. A comparison between the measured index of refraction and theoretical calculation based on molar refraction is made. Also the temporal behavior of both the refractive index and extinction coefficient is compared. METHODS: Index of refraction: BisGMA/TEGDMA monomer samples were cured with a commercial light-curing unit by using camphorquinone and DMAEMA as the photoinitiator system. Curing times of 0, 40, 60, 300, 900 and 1800s were used. The refractive indices were determined with a refractometer at 470nm wavelength, where the peak absorption of the camphorquinone photoinitiator is located. Extinction coefficient: BisGMA/TEGDMA samples having different lengths were cured and the relative attenuation of light at 470nm was measured as a function of the curing time (0, 40, 60, 300, 900, 1800s). RESULTS: The results show that in general the index of refraction increases during the photopolymerization process in a time frame from 0 to 40s and then approaches a steady-state value, which depends on the original composition of the admixture. The detailed refractive index change depends on the volume fractions of the constituent substances. The extinction coefficient decreases in a time frame from 60 to 900s and reaches a steady-state value thereafter. SIGNIFICANCE: Knowledge of the fundamental optical characteristics of commonly used dental polymers is essential in the development of advanced light-initiated curing methods.     

Fatigue behaviour of dental composite materials

Objective

The intent of the project was to evaluate the fatigue behavior of particle and fiber filled dental composites that are fabricated either directly or indirectly using a notched specimen with respect to the number of cycles until failure.

Methods

The materials were five dental composites, three normally cured in the oral cavity (Restolux, Renew and Filtek Supreme), direct processing, and two laboratory produced (BelleGlass, and Tescera), indirect processing. The specimens were 3 mm × 3 mm × 25 mm bars with a 0.75 or 1.0 mm notch in the mid-span of the bars, polished with 320 grit SiC paper and aged for 6 months in air, distilled water, artificial saliva, and a 50/50 mixture of ethanol and distilled water. Testing was performed with a stress mean range of 5–49 MPa, the maximum number of cycles was 100,000, and the number of cycles to failure was recorded.

Results

For the specimens that failed, BelleGlass, Restolux, and Tescera were able to withstand a higher cyclic loaded stress than Renew and Filtek. The 50/50 by volume mixture of water and ethanol resulted in the lowest resistance to fatigue for all materials.

Conclusions

Of the dental composite materials investigated, the indirect processed and those with large particle fillers (higher weight percent filler) had better cyclic fatigue resistance than micro- and nano-particle fillers (lower weight percent filler).     

复合树脂用丙烯酸液晶单体的合成与表征

目的:合成一种新型的树脂基质主单体——丙烯酸液晶单体(ALCRM),即4-(3-丙烯酰氧基-2-羟基丙氧基)苯甲酸4'-(3-丙烯酰氧基-2-羟基丙氧基)苯甲酯.方法:本实验采用三步法,第一步:对苯二酚与对羟基苯甲酸合成介晶基元-HPHB;第二步:合成环氧化合物EPEB;第三步:合成终产物ALCRM.通过示差扫描量热法(DSC),偏光显微镜(POM),核磁共振(HNMR)3种方法检测合成过程中间产物及终产物的液晶性能以及终产物的介晶域.结果:HNMR检测证实HPHB、EPEB、ALCRM为目标产物.经POM,DSC检测ALCRM具有液晶性能,介晶范围是18 ～42℃.结论:本研究合成含短的柔性间隔链的ALCRM单体,降低了液晶单体的相转化温度,更适用于口腔临床的操作.     

Effect of bleaching on the elution of monomers from modern dental composite materials

ObjectiveThe aim of this study was to evaluate the effect of bleaching on the elution of monomers from two modern composite materials.MethodsTwo different resin composites (a nanohybrid the Filtek Supreme? XT and an ormocer the Ceram X?) were bleached with two products (hydrogen peroxide 38% for 45 min and carbamide peroxide 15% for 56 h). Four groups (n = 10, diameter: 4.5 mm, thickness: 2 mm) of each material were fabricated, two for each bleaching product. One group was used as unbleached control and the other one was bleached. Then the samples were stored in 1 ml of 75 vol% ethanol at room temperature, and the storage medium was renewed after 24 h, 7 days, and 28 days. From the storage medium that was removed samples were prepared and analysed with LC–MS/MS.ResultsNone of the bleaching products had an effect on the amount of Bis-GMA and TEGDMA released from Ceram X?. The amount of Bisphenol A released from the bleached samples of Ceram X? was significantly lower compared to the control samples. Bleaching reduced significantly the amount of Bis-GMA released from Filtek Supreme? XT. The amount of TEGDMA released from Filtek Supreme? XT was not affected by bleaching.SignificanceThe bleaching agents tested in the present study reduced the amount of some of the monomers released from the two composite materials. Bleaching of modern composite materials does not increase the release of monomers.     

Involvement of oxidative stress in mutagenicity and apoptosis caused by dental resin monomers in cell cultures

OBJECTIVE: This investigation studied the possibility that apoptosis as well as mutagenicity induced by resin monomers are mediated by oxidative stress. METHODS: A range of dilutions of three resin monomers (GMA, TEGDMA, and HEMA) was added to culture medium (DMEM/10% FBS), of V79-4 fibroblasts and RPC-C2A pulp cells for 24 h. Their cytotoxic effects were measured by a colorimetric functional assay (MTT). Chromosomal aberration induced by the resin monomers was investigated by counting micronuclei in V79-4 cells. The effects of the resin monomers on DNA fragmentation were viewed by agarose gel electrophoresis of DNA, isolated from RPC-C2A pulp cells that were treated by resin compounds. Resin monomer-induced apoptosis was further confirmed by flow cytometry (staining with both annexin V-FITC and PI). RESULTS: All monomers exhibited a dose-dependent cytotoxic effect, and the ranking of the cytotoxicity based on TC50 was GMA > TEGDMA > HEMA. The resin monomer-induced cytotoxicity was significantly decreased by co-treatment with N-acetylcystein (NAC), an antioxidant. The authors also confirmed a dose-dependent genotoxicity of the resin monomers that had induced micronucleated cells in V79-4 fibroblasts. Similar to the effects on cytotoxicity, NAC reduced the numbers of micronuclei in comparison with those generated by the resin monomers. The preventive effects of NAC were also observed in monomer-induced apoptosis in RPC-C2A cells. A DNA ladder pattern, characteristic of apoptosis, was shown at cytotoxic concentrations, but NAC blocked the resin monomer-mediated DNA fragmentation. The preventive effects of NAC on apoptosis were confirmed by Annexin V staining. Cells exposed to 300 microM GMA, 7 mM TEGDMA, or 14 mM HEMA for 24 h showed a significant increase in apoptotic cells, while NAC co-treatment caused a reduction in apoptotic cells compared to controls. SIGNIFICANCE: These findings suggest that glutathione depletion and oxidative stress are responsible for GMA, TEGDMA, and HEMA-induced mutagenicity and apoptosis.     

Degradation of polymeric restorative materials subjected to a high caries challenge

Objectives

The aim of this study was to evaluate the degradation of different resin filling materials after a caries challenge, by high performance liquid chromatography (HPLC) and contact angle (θ) measurement.

Methods

Four different polymeric restorative materials (a resin composite, a polyacid-modified resin composite, an ormocer and a resin-modified glass ionomer cement) were tested. Five samples (30 mm × 6 mm × 2 mm) of each material were formed in a Teflon mold, following the manufacturer's instructions. After pH cycles, the solutions were injected in an HPLC. The θ was obtained, before and after pH cycle, by a goniometer at 60% air humidity and 25 °C. A distilled water drop (0.006 ml) was put on the material surface, and after 6 min, 10 measures were obtained at 20 s intervals. Each sample received 4 drops, one at a time, on different areas.

Results

HPLC results showed elution of byproducts in all materials. This was greater in the acid medium. Bis-GMA and TEGDMA were detected in TPH Spectrum and Definite residues. Analyses of the contact angle by ANOVA and Student-Neuman-Keuls's test showed that the surfaces of TPH Spectrum, Dyract AP and Definite were altered, except Vitremer (p < 0.05).

Significance

All materials tested degraded on a caries simulated medium, suggesting that a great effort should be made to disseminate oral health information, since a high caries challenge environment (low pH) can lead to dental composite degradation, with potential toxic risks to patients.     

聚合方法对基托材料残留单体的影响——高效液相色谱法分析MMA含量

采用同种国产牙托粉和牙托水，通过４种方法（自凝法、水浴加热法、气压法和微波法）进行聚合，将聚合后的片状样品和粉状样品浸泡在甲醇溶液中，采用高效液相色谱仪测定不同时间溶出物中的ＭＭＡ含量。结果表明，自凝法、气压法、水浴加热法和微波法制备的基托样品中的残余单体量（Ｗｔ％）分别是１．６１３、０．４３８、０．３３６和０．２２１。微波法聚合较完全。     

Characteristics of experimental resin-modified glass-ionomer cements,containing alternate monomers to HEMA

ObjectiveResin-modified glass ionomer cements (RMGICs) present several advantages (e.g. fluoride release), but their reported cytotoxicity has been associated with hydroxyethyl methacrylate (HEMA) monomer release. Therefore, different monomers were tested for use in RMGICs in order to improve their biocompatibility and reduce monomer release.MethodsEight experimental liquid compositions were prepared replacing different percentages of HEMA (conventional monomer used in commercial RMGICs) with hydroxypropyl-methacrylate (HPM) and/or tetrahydrofurfuryl-methacrylate (THFM), which are known to have better biocompatibility. Moreover, two commercial materials (Fuji-Plus and RelyX) and two compositions, based on these (home), were included as controls. Monomer release of all materials (commercial, home and experimental) were tested using high-performance liquid chromatography (HPLC) methods after immersing discs in deionized-water (DW) or ethanol:DW. Cytotoxicity of the materials extracts was tested on normal human oral fibroblast line (NHOF-1) using 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay.ResultsThree experimental materials containing THFM (F3, R3 and R4) showed less or similar monomer release compared to corresponding commercial products. Furthermore, two experimental materials (F3 and F4) showed similar effects on NHOF-1 cells compared to the negative control medium.SignificanceThe lower monomer release and higher cell viability of some experimental THFM compositions are encouraging. THFM partially replacing HEMA is potentially a suitable alternative for producing biocompatible RMGICs.     

Two year clinical evaluation of a low-shrink resin composite material in UK general dental practices

Objective

A novel resin composite system, Filtek Silorane (3M ESPE) with reduced polymerization shrinkage has recently been introduced. The resin contains an oxygen-containing ring molecule (‘oxirane’) and cures via a cationic ring-opening reaction rather than a linear chain reaction associated with conventional methacrylates and results in a volumetric shrinkage of ∼1%. The purpose of this study was to review the literature on a recently introduced resin composite material, Filtek Silorane, and evaluate the clinical outcome of restorations formed in this material.

Methods

Filtek Silorane restorations were placed where indicated in loadbearing situations in the posterior teeth of patients attending five UK dental practices. These were evaluated, after two years, using modified USPHS criteria.

Results

A total of 100 restorations, of mean age 25.7 months, in 64 patients, were examined, comprised of 30 Class I and 70 Class II. All restorations were found to be present and intact, there was no secondary caries. Ninety-seven per cent of the restorations were rated optimal for anatomic form, 84% were rated optimal for marginal integrity, 77% were rated optimal for marginal discoloration, 99% were rated optimal for color match, and 93%% of the restorations were rated optimal for surface quality. No restoration was awarded a “fail” grade. No staining of the restoration surfaces was recorded and no patients complained of post-operative sensitivity.

Significance

It is concluded that, within the limitations of the study, the two year assessment of 100 restorations placed in Filtek Silorane has indicated satisfactory clinical performance.     

High refractive index monofunctional monomers as promising diluents for dental composites

ObjectivesTo evaluate high refractive index methacrylates as diluents for the formulation of radiopaque esthetic bulk-fill composites.Methods2-(4-Cumylphenoxy)ethyl methacrylate 1, 2-(2-phenylphenoxy)ethyl methacrylate 2 and 2-[2-(2-phenylphenoxy)ethoxy]ethyl methacrylate 3 were synthesized and characterized by ¹H NMR spectroscopy. The reactivity of each monomer was studied using photo-DSC. Bulk-fill composites based on monomers 1–3 were formulated. Translucency (before and after light cure) was measured using a spectrophotometer. The depth of cure and the water sorption of these materials were determined according to ISO 4049. The flexural strength and modulus of elasticity were measured using a three-point bending setup, according to ISO 4049. The shrinkage force was assessed based on a method described by Watts et al. using a universal testing machine.ResultsMonomers 1–3 were easily synthesized in two steps. They exhibit a low viscosity and a high refractive index (1.553–1.573). Monofunctional methacrylates 1–3 were found to be more reactive than triethylene glycol dimethacrylate (TEGDMA). Bulk-fill composites based on these monomers were successfully prepared. They exhibit a high depth of cure and excellent esthetic properties (low transparency). These composites provide higher flexural modulus as well as lower water sorption than a corresponding material based on TEGDMA. Methacrylates 1 and 3 are particularly interesting as they led to composites showing lower shrinkage force.SignificanceMethacrylates 1–3 are promising diluents for the formulation of highly esthetic radiopaque bulk-fill composites.     

In vitro investigation of coupling-agent-free dental restorative composite based on nano-porous alumina fillers

Objectives

The study aims at demonstrating the feasibility of a novel type of coupling-agent-free resin composite based on nano-porous fillers.

Methods

The fillers were obtained by ball-milling anodic alumina membranes. Composites were prepared with standard resin at maximum loading of 50% by weight. The resin matrix penetration into the pores was verified visually by scanning electron microscopy and mechanically by atomic force microscopy in force modulation mode. The dynamic flexural modulus at 1 Hz was measured by dynamic mechanical analysis. Silver nanoparticles were also synthesized in the pores and their release was investigated with inductive coupled plasma optical emission spectrometry.

Results

A storage modulus of 5 GPa was measured, similar to the ∼6 GPa ones of two coupling-agent-based dental restorative composites used for comparison, which is a promising starting point, additionally showing better one-year equivalent ageing as compared to both commercial materials. Loading the pores with silver nanoparticles was demonstrated as well as their subsequent release in a model system.

Significance

The alumina micro-particles with interconnected nano-pores allow mechanical interlocking between fillers and matrix without the need for chemical bonding. This material is also promising for being made bio-active, after pore filling with different agents.     

Eugenol: liberation from dental materials and effect on human diploid fibroblast cells

The amount of eugenol (4-allyl-2-methoxyphenol) released from four different dental materials immersed in phosphate buffer was measured by gas liquid chromatography. Maximal release of eugenol from zinc oxide-eugenol cement (ZOE) and IRM® was attained within 5 h and corresponded to 5% and 4%, respectively, of the total amount of eugenol in each material. Both the rates and total amounts of eugenol released from Nobetec® and Opotow® were lower than for ZOE and IRM. Eugenol (0.67 mm) applied to growing cultures of human diploid fibroblasts reduced the number of cells recovered to a value which was 4%. of that found for control cultures which grew to form, monolayers. Confluent monolayers of ³H-uridine labeled cell cultures which were incubated for 1 h in the presence of 4 mm eugenol lost approximately 100% of this cytoplasmic label, indicating total cell death.     

Longevity of posterior composite restorations: Not only a matter of materials

Resin composites have become the first choice for direct posterior restorations and are increasingly popular among clinicians and patients. Meanwhile, a number of clinical reports in the literature have discussed the durability of these restorations over long periods. In this review, we have searched the dental literature looking for clinical trials investigating posterior composite restorations over periods of at least 5 years of follow-up published between 1996 and 2011. The search resulted in 34 selected studies. 90% of the clinical studies indicated that annual failure rates between 1% and 3% can be achieved with Class I and II posterior composite restorations depending on several factors such as tooth type and location, operator, and socioeconomic, demographic, and behavioral elements. The material properties showed a minor effect on longevity. The main reasons for failure in the long term are secondary caries, related to the individual caries risk, and fracture, related to the presence of a lining or the strength of the material used as well as patient factors such as bruxism. Repair is a viable alternative to replacement, and it can increase significantly the lifetime of restorations. As observed in the literature reviewed, a long survival rate for posterior composite restorations can be expected provided that patient, operator and materials factors are taken into account when the restorations are performed.     

Monomer elution from nanohybrid and ormocer-based composites cured with different light sources

Objectives

To study monomer elution from four resin-based composites (RBCs) cured with different light sources.

Methods

Twenty-eight premolars were randomly allocated to four groups. Standardized cavities were prepared and restored with a nanohybrid (Filtek Supreme XT or Tetric EvoCeram), an ormocer (Admira) or a microhybrid RBC (Filtek Z250) which served as control. Buccal restorations were cured with a halogen and oral restorations with an LED light-curing unit. Elution of diurethane dimethacrylate (UDMA), Bisphenol A diglycidylether methacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA) and 2-hydroxyethyl methacrylate (HEMA) was analyzed using high-performance liquid chromatography (HPLC) 1 h to 28 days post-immersion in 75% ethanol. Data were analyzed using multivariate and repeated measures analysis of variance (α = 0.05).

Results

The greatest elution of UDMA and BisGMA occurred from Tetric EvoCeram and the least from Filtek Z250 (p < 0.05). LED and halogen light-curing units gave similar results for all RBCs (p > 0.05) except Tetric EvoCeram which showed greater elution for the LED unit (p < 0.05). TEGDMA was below the limit of quantification. HEMA eluted in similar concentrations from Filtek Supreme and Tetric EvoCeram (p > 0.05).

Significance

: The two nanohybrid RBCs eluted more cross-linking monomers than the ormocer and the control microhybrid RBC. Continuous elution over 28 days indicates that RBCs act as a chronic source of monomers in clinical conditions. Light source may affect monomer elution since differences were found for one out of four RBCs. Mathematical models for elution kinetics of UDMA and BisGMA indicated two elution mechanisms.     

A review and current state of autonomic self-healing microcapsules-based dental resin composites

ObjectiveThis study systematically reviews the literature on self-healing microcapsule technology and evaluates the biocompatibility of self-healing microcapsules and the efficiency of crack repair within resin-based dental composites.MethodsAn electronic search was carried out using the following databases: MedLine (PubMed), Embase, the Cochrane Library and Google Scholar. All titles and abstracts of the articles and patents found were analysed and selected according to the eligibility criteria. Only studies published in English were included; the outcomes sought for this review were dental resin composites with self-healing potential. There were no restrictions on the type of self-healing system involved in dental resin composites.ResultsThe search yielded 10 studies and 2 patents involving self-healing approaches to dental resin composites. According to the current literature on self-healing dental resin composites, when a crack or damage occurs to the composite, microcapsules rupture, releasing the healing agent to repair the crack with a self-healing performance ranging from 25% to 80% of the virgin fracture toughness.SignificanceSelf-healing strategies used with resin composite materials have, to date, been bioinspired. So far, self-healing microcapsule systems within dental composites include poly urea-formaldehyde (PUF) or silica microcapsules. The main healing agents used in PUF microcapsules are DCPD monomer and TEGDMA-DHEPT, with other agents also explored. Silica microcapsules use water/polyacid as a healing agent. All self-healing systems have shown promising results for self-repair and crack inhibition, suggesting a prolonged life of dental composite restorations. More investigations and mechanical enhancements should be directed toward self-healing technologies in dental resin composites.