Evaluation of mechanical, optical, and fluoride-releasing properties of a translucent bulk fill glass hybrid restorative dental material.

OBJECTIVE: Measure and compare the mechanical properties, translucency, and fluoride-releasing capabilities of EQUIA Forte HT against Fuji IX GP and ChemFil Rock. MATERIALS AND METHODS: Ten specimens of each material were fabricated for compressive strength (CS), flexural strength (FS), and surface hardness analysis at 24 h and 7 days. The L*a*b* values were measured against a black-and-white background using a spectrophotometer to analyze the translucency parameter (TP). Fluoride release was recorded after 2 months of immersion in distilled water. The mean data was analyzed by 1- and 2-way ANOVA (α = 0.5). RESULTS: EQUIA Forte HT showed higher CS, surface hardness, and FS values (p < 0.05) compared with Fuji IX GIC, while no significant difference was found in FS values between EQUIA Forte HT and Chemfil Rock (p > 0.05). The EQUIA Forte HT exhibited significantly higher translucency in comparison to both ChemFil Rock (p < 0.001) and Fuji IX GICs (p < 0.05). An increase (p > 0.05) of fluoride release was observed for EQUIA Forte HT. CONCLUSION: The EQUIA Forte HT Glass-ionomer cements (GIC) offers enhanced translucency, improved strength, and enhanced fluoride-releasing properties compared to the traditionally used Fuji IX GIC and ChemFil Rock GICs. This material might have a wide range of clinical applications due to its improved strength and optical properties. CLINICAL SIGNIFICANCE: Glass-ionomer dental restorative materials possess unique advantageous characteristics. However, its poor mechanical and optical properties have typically limited its clinical applications. Efforts to improve these properties have resulted in enhanced GICs. EQUIA Forte HT GIC offers enhanced mechanical and optical properties with potential applications in posterior and anterior restorative procedures.

Revised FDI criteria for evaluating direct and indirect dental restorations-recommendations for its clinical use, interpretation, and reporting.

OBJECTIVES: The FDI criteria for the evaluation of direct and indirect dental restorations were first published in 2007 and updated in 2010. Meanwhile, their scientific use increased steadily, but several questions from users justified some clarification and improvement of the living document. MATERIALS AND METHODS: An expert panel (N = 10) initiated the revision and consensus process that included a kick-off workshop and multiple online meetings by using the Delphi method. During and after each round of discussion, all opinions were collected, and the aggregated summary was presented to the experts aiming to adjust the wording of the criteria as precisely as possible. Finally, the expert panel agreed on the revision. RESULTS: Some categories were redefined, ambiguities were cleared, and the descriptions of all scores were harmonized to cross-link different clinical situations with possible management strategies: reviewing/monitoring (score 1-4), refurbishment/reseal (score 3), repair (score 4), and replacement (score 5). Functional properties (domain F: fracture of material and retention, marginal adaptation, proximal contact, form and contour, occlusion and wear) were now placed at the beginning followed by biological (domain B: caries at restoration margin, hard tissue defects, postoperative hypersensitivity) and aesthetic characteristics (domain A: surface luster and texture, marginal staining, color match). CONCLUSION: The most frequently used eleven categories of the FDI criteria set were revised for better understanding and handling. CLINICAL RELEVANCE: The improved description and structuring of the criteria may help to standardize the evaluation of direct and indirect restorations and may enhance their acceptance by researchers, teachers, and dental practitioners.

Feasibility of optimizing intensity-modulated radiation therapy plans based on measured mucosal dose adjacent to dental fillings and toxicity outcomes.

We prospectively investigated the feasibility of IMRT treatment plan optimization based on dosimeter measurements of lateral tongue mucosal dose adjacent to the dental fillings and evaluated dose-toxicity relationship and factors affecting oral mucositis (OM) in head and neck cancer patients. Twenty-nine head and neck cancer patients with metallic dental fillings who were scheduled to undergo fractionated external beam radiation therapy (RT) ± chemotherapy were enrolled. The lateral tongue dose was measured and if the calculated dose for the entire treatment was ≥35 Gy, a re-plan was generated to reduce the lateral tongue mucosal dose. OM was graded weekly according to Common Terminology Criteria for Adverse Events version 4.0 and the patients completed the Oral Mucositis Weekly Questionnaire-Head and Neck Cancer. The result showed that it was not feasible to optimize the IMRT plan based on measured tongue dose in most of the patients who needed re-plan as re-planning compromised the target coverage in 60% of these patients. The duration of grade (Gr) 2 OM was correlated with measured lateral tongue dose (P = 0.050). Concurrent cetuximab was significantly associated with faster onset of Gr2 OM than concurrent cisplatin (P = 0.006) and with longer duration of OM (P = 0.041) compared to concurrent cisplatin or IMRT-alone. The pattern of reported pain over time was significantly different for each treatment type (RT and cetuximab, RT and cisplatin and RT-alone) and depending on the dose level (P = 0.006). In conclusion, optimizing the IMRT plan based on measured lateral tongue dose was not feasible. Measured lateral tongue dose was significantly correlated with longer duration of OM ≥Gr2, and concurrent cetuximab was associated with earlier onset and longer duration of OM ≥Gr2.

Polymer-based dental filling materials placed during pregnancy and risk to the foetus.

BACKGROUND: Tooth-coloured polymer-based dental filling materials are currently the first choice for dental restorative treatment in many countries. However, there are some concerns about their safety. It has been shown that substances known as endocrine disrupters, which might pass through the placental barrier, are released from these materials within the first hours after curing. Thus, the placement of polymer-based dental fillings in pregnant women may put the vulnerable foetus at risk. Large epidemiological studies exploring the risk of having polymer-based dental materials placed during pregnancy are lacking. The aim of this study was to investigate the association between the placement of polymer-based dental fillings during pregnancy and adverse birth outcomes. METHODS: This study is based on data from the large Norwegian Mother and Child Cohort Study (MoBa). The information about dental treatment during pregnancy was obtained from questionnaires sent to the participating women during weeks 17 and 30 of pregnancy. Reported placement of "white fillings" was used as exposure marker for having received polymer-based dental filling materials. Only singleton births were included in the present study. Data were linked to the Medical Birth Registry of Norway. Logistic regression models that included the mother's age, level of education, body mass index, parity, and smoking and alcohol consumption during pregnancy were used to estimate the odds ratio (OR) and 95% confidence interval (CI). Different adverse birth outcomes were of interest in the present study. RESULTS: Valid data were available from 90,886 pregnancies. Dentist consultation during pregnancy was reported by 33,727 women, 10,972 of whom had white fillings placed. The adjusted logistic regression models showed no statistically significant association between having white dental fillings placed during pregnancy and stillbirth, malformations, preterm births, and low or high birth weight. CONCLUSIONS: In this study, women who reported white fillings placed during pregnancy had no increased risk for adverse birth outcomes compared with women who did not consult a dentist during pregnancy. Thus, our findings do not support the hypothesis of an association between placement of polymer-based fillings during pregnancy and adverse birth outcomes.

The dawn of dentistry in the late upper Paleolithic: An early case of pathological intervention at Riparo Fredian.

OBJECTIVES: Early evidence for the treatment of dental pathology is found primarily among food-producing societies associated with high levels of oral pathology. However, some Late Pleistocene hunter-gatherers show extensive oral pathology, suggesting that experimentation with therapeutic dental interventions may have greater antiquity. Here, we report the second earliest probable evidence for dentistry in a Late Upper Paleolithic hunter-gatherer recovered from Riparo Fredian (Tuscany, Italy). MATERIALS AND METHODS: The Fredian 5 human consists of an associated maxillary anterior dentition with antemortem exposure of both upper first incisor (I1 ) pulp chambers. The pulp chambers present probable antemortem modifications that warrant in-depth analyses and direct dating. Scanning electron microscopy, microCT and residue analyses were used to investigate the purported modifications of external and internal surfaces of each I1 . RESULTS: The direct date places Fredian 5 between 13,000 and 12,740 calendar years ago. Both pulp chambers were circumferentially enlarged prior to the death of this individual. Occlusal dentine flaking on the margin of the cavities and striations on their internal aspects suggest anthropic manipulation. Residue analyses revealed a conglomerate of bitumen, vegetal fibers, and probable hairs adherent to the internal walls of the cavities. DISCUSSION: The results are consistent with tool-assisted manipulation to remove necrotic or infected pulp in vivo and the subsequent use of a composite, organic filling. Fredian 5 confirms the practice of dentistry-specifically, a pathology-induced intervention-among Late Pleistocene hunter-gatherers. As such, it appears that fundamental perceptions of biomedical knowledge and practice were in place long before the socioeconomic changes associated with the transition to food production in the Neolithic.

Four-year outcomes of restored posterior tooth surfaces-a massive data analysis.

OBJECTIVES: There is only sparse knowledge concerning the outcomes of treatments with posterior permanent restorations in general practice settings. This study aimed at evaluating outcomes based on a large dataset by using a novel approach on a tooth surface basis. MATERIALS AND METHODS: The study based on routine data from a major German national health insurance company. Respective treatment fee codes allowed for tracking the clinical courses on a tooth surface level. The study intervention was defined as the placement of a restoration on an interproximal or occlusal posterior tooth surface regardless of its actual extension and material on which no information was available. All surfaces restored between January 1st, 2010 and December 31st, 2013 were included. Kaplan-Meier survival analyses were conducted to estimate four-year survival. The primary outcome was a restorative re-intervention on the same tooth surface. Separate analyses were performed for the secondary outcomes "crowning" and "extraction". RESULTS: Over ten million interproximal surfaces and eight million occlusal surfaces in nine million posterior teeth had been restored. At 4 years, the cumulative survival rates concerning the primary outcome "re-intervention" for mesial surfaces (81.4%; CI 81.3-81.5%) and distal surfaces (81.2%; CI 81.1-81.2%) differed significantly from those for occlusal surfaces (77.0%; CI 76.9-77.0%). Restored surfaces in premolars showed significantly higher survival rates compared to molars. Four-year survival rates for the secondary outcome "crowning" were 91.9% (CI 91.8-91.9%) for mesial surfaces, 92.1% (CI 92.1-92.2%) for distal surfaces and 93.3% (CI 93.2-93.3%) for occlusal surfaces. The respective rates for the secondary outcome "extraction" were 94.5% (CI 94.5-94.5%) for mesial surfaces, 94.8% (CI 94.7-94.8%) for distal surfaces and 95.4% (CI 95.4-95.5%) for occlusal surfaces. CONCLUSIONS: Re-interventions after restorative treatment play a significant role in general practice settings. Surface-related survival rates of restorations reveal a need for improvement. CLINICAL RELEVANCE: This study allows the estimation of the probability of re-interventions after restoring posterior tooth surfaces. It is based on several million cases from general practises under the terms and conditions of a national health insurance system.

Synchrotron-radiation-based X-ray micro-computed tomography reveals dental bur debris under dental composite restorations.

Dental burs are used extensively in dentistry to mechanically prepare tooth structures for restorations (fillings), yet little has been reported on the bur debris left behind in the teeth, and whether it poses potential health risks to patients. Here it is aimed to image dental bur debris under dental fillings, and allude to the potential health hazards that can be caused by this debris when left in direct contact with the biological surroundings, specifically when the debris is made of a non-biocompatible material. Non-destructive micro-computed tomography using the BioMedical Imaging & Therapy facility 05ID-2 beamline at the Canadian Light Source was pursued at 50 keV and at a pixel size of 4 µm to image dental bur fragments under a composite resin dental filling. The bur's cutting edges that produced the fragment were also chemically analyzed. The technique revealed dental bur fragments of different sizes in different locations on the floor of the prepared surface of the teeth and under the filling, which places them in direct contact with the dentinal tubules and the dentinal fluid circulating within them. Dispersive X-ray spectroscopy elemental analysis of the dental bur edges revealed that the fragments are made of tungsten carbide-cobalt, which is bio-incompatible.

Assessing the impact of dental restorative materials on fibroblast cells: an immunohistochemical and ELISA analysis.

In this study, our aim was to investigate the effects of restorative materials such as composite, compomer and high viscosity glass ionomer, which are frequently used in dentistry, on L929 fibroblast cells by evaluating the oxidative stress parameters, pro- and anti-inflammatory cytokines, and apoptosis markers. L929 fibroblast cells were cultured, and dental filling materials were applied in two doses (50 and 100 µl). Immunohistochemical staining was performed for experimental groups with Anti-Bax and Anti-Caspase 9 antibodies. Then, ELISA technique was used to detect the level of TNF-alpha, TGF-beta, IL-1-beta, IL-6, IL-10, LPO and CAT. In the light of the data, the examined dental filling materials were effective on increasing the TGF-beta, IL-10, LPO and CAT levels, and decreasing the TNF-alpha, IL-1-beta, and IL-6 levels. The histological micrographs were also support the issues. When the levels of H-score in Caspase 9 labeled micrographs were evaluated, the mean of the control group was lower than the mean of the experimental groups. Biocompatibility varies according to the content of the material, the amount of residual monomer, and its solubility. Although all the experimental groups have cytotoxic effects, the least effect is seen in the Omnichroma group.

Awareness of possible complications associated with direct composite restorations: A multinational survey among dentists from 13 countries with meta-analysis.

OBJECTIVES: Resin-based composites (RBCs) evolved into favoured materials for teeth restorations, marking a significant change in dental practice. Despite many advantages, RBCs exhibit various limitations in their physical and chemical properties. Therefore, we assessed the dentists' awareness of possible complications after direct composite restorations and their opinions about this material. METHODS: The online questionnaire was created in English in May 2023. A 16-item survey was dedicated to general dentists and specialists. The first section included four questions related to demographic characteristics. The second section comprised twelve questions and focused on awareness of potential side effects of composite restorations, the most crucial advantages and disadvantages of composite resins, and the frequency of experienced clinical complications after the application of composite materials. RESULTS: A total of 1830 dentists from 13 countries took part in the survey. Dentists most often declared awareness of low adhesion to the dentine (77.5 %) and, most rarely, solubility in oral fluids (42.6 %). Aesthetics was identified as the main advantage of composite fillings (79 %), followed by the possibility of repair (59 %) and adhesion to enamel (57 %). Polymerisation shrinkage was a major disadvantage for most countries (70 % overall). Analysing the declared potential clinical complications for all countries, statistically significant findings were obtained for marginal discolouration (OR=2.982, 95 % CI: 1.321-6.730, p-value=0.009) and borderline significance for secondary caries (OR=1.814, 95 % CI: 0.964-3.415, p-value=0.065). CONCLUSIONS: Dentists value aesthetics and repairability but are aware of shrinkage and experience discolouration. The issue of toxicity and solubility seems to be the least known to dentists. CLINICAL SIGNIFICANCE: Dentists should use RBCs with critical caution due to possible side effects. Despite the undoubted aesthetics of direct composite restorations, it is necessary to remember potential clinical complications such as marginal discolouration or secondary caries.

Highly Efficient Photoinitiation Systems Based on Dibenzo[a,c]phenazine Sensitivity to Visible Light for Dentistry.

In this work, photoinitiation systems based on dibenzo[a,c]phenazine sensitivity to visible light were designed for their potential application in dentistry. Modification of the structure of dibenzo[a,c]phenazine consisted of introducing electron-donating and electron-withdrawing substituents and heavy atoms into position 11. The synthesized compounds are able to absorb radiation emitted by dental lamps during photoinitiation of the polymerization process. In the presence of acrylates, dibenzo[a,c]phenazines show excellent photoinitiating abilities in systems containing an electron donor or a hydrogen-atom donor as a second component. The developed systems initiate the polymerization process comparable to a commercial photoinitiator, i.e., camphorquinone. Moreover, the performed studies showed a significant shortening of the polymerization time and a reduction in the amount of light absorber. This indicates that polymeric materials are obtained at a similar rate despite a significant reduction in the concentration of the newly developed two-component photoinitiating systems.

Clinical Difficulties Related to Direct Composite Restorations: A Multinational Survey.

AIMS: Composite materials are widely used in dentistry for direct tooth restorations. However, they are highly sensitive to the working technique employed during the restorative procedure. Even minor procedural errors can have a significant impact on the quality including the longevity of the restoration. Hence the aim of this study was to determine the material preferences and analyse the clinical problems associated with direct composite restorations in a cohort of dentists. METHODS: A 20-item online questionnaire was created in English and administered 1830 general dentists and specialists in 13 countries. The first section of the questionnaire included four questions to elicit demographic data, and the second section comprised 16 questions focused on material preferences for conservative restorations, durability of composite restorations, and the most challenging stages the dentists faced during the composite restorative procedures. RESULTS: Respondents decided most often to use composite materials for the tooth restorations (OR 997.4, 95% CI 233.8-4254.8, P value <.001). Most respondents indicated that the durability of composite restorations was approximately 7 to 10 years (41.5%). Among the factors affecting durability, maintenance of a dry cavity was the most often reported reason (47.1%) and the foremost challenge faced by dentists (61.0%) during the composite restorative procedures. CONCLUSIONS: Our study confirmed that resin-based composites are the most popular material for direct restoration in many countries. Although working with this material is difficult and involves multiple steps, maintaining a dry cavity during bonding, and material application may affect the therapeutic success and durability of these restorations. Clinicians need to be attentive to this issue and be prepared to adapt their decision-making and consider opting for alternative restorative materials, if appropriate.

Performance of restorations in primary molars over a seven-year period.

OBJECTIVE: The aim of this study was to evaluate the use and reintervention rate of fillings compared to preformed metal crowns in the everyday clinical practice of German dentists. METHODS: In this retrospective, longitudinal analysis, fee codes from the Kassenzahnärztliche Vereinigung Westfalen-Lippe for restorations placed in primary molars between 2012 and 2015 in children until 7 years of age followed for a 7-year period (latest until December 2022) were filtered and analyzed with the Fine and Gray competing risk regression and Cox proportional hazards regression to calculate the risk of reintervention divided into the main outcomes "Successful", "Minor Failure/Repair" and "Major Failure/Endodontic Treatment/Extraction". 367,139 primary molars (one-surface fillings: n = 117,721; two-surface fillings n = 198,815; three-surface fillings n = 36,695; more than three-surface fillings n = 8,267 and preformed metal crowns n = 5,641 were included in this study. RESULTS: Teeth treated with preformed crowns needed significantly less re-interventions. Subdistribution hazard ratio for minor events was 0.117 (95 %-CI: 0.097 to 0.141) and hazard ratio of major events (HR=0.786; 95 %-CI: 0.695 to 0.890) when compared to one-surface fillings in multivariable adjusted analysis. Within 7-year follow-up preformed crowns required less repairs (80.6 % success rate, minor failure 4.4 %, major failure 16.3 %) than the teeth treated with composite fillings (46.2 %-52.6 % success rate, minor failure 27.0 %-39.5 %, major failure 15.5 %-28.4 %, p < 0.001). CONCLUSION: Within the German healthcare system fillings are the first choice for treating primary molars despite considerably higher reintervention rates. This encourages a discussion on the indication of fillings and the more durable preformed metal crowns to reduce unnecessary reintervention in young children. CLINICAL SIGNIFICANCE: This study gives an unprecedented insight into the German healthcare system regarding the reintervention rates of the most relevant treatment techniques for caries in primary molars.

Extension of the working time of dental composites due to a new type of white operating lamp.

OBJECTIVES: Dental composite materials for filling teeth are usually hardened by polymerisation lamps emitting blue light. However, the same wavelength is also emitted by light of dental operating lamps for lighting the oral cavity. Thus, the hardening of the composite is already initiated earlier, shortening the time of formability. The objective of this study is to develop a specific white LED for dental operating lamps. When restoring teeth, it enables dentists to work longer on light-curing composites in the same brightness. METHODS: Based on a short-wave blue coloured LED and a fluorescent substance, a white luminescent LED with a colour temperature of approx. 3,000 K is produced as a prototype. The formable working times of three composites are measured for this LED and two dental head lamps at an illuminance of 10,000 lx. RESULTS: Shorter working times of 98-237 s were measured for the headlamps and 409-807 s for the new LED. This light of the new LED is perceived by the human eye as warm white. CONCLUSIONS: The new LED extends the working time by the factor of 3.0 to 5.8 compared to the head lamps. This enables more precise modelling of fillings.

Experimental Investigations of the Dental Filling Materials: Establishing Elastic Moduli and Poisson's Ratios.

The mechanical properties of the dental filling material (DFMs) strongly influence the lifetime and durability of the tooth reparation performed. Among the most significant mechanical characteristics, one has to mention the Poisson's ratio and the elastic modulus (Young's modulus). They, during the cyclic mastication load, can prevent or aid in the prevention of secondary dental decays by provoking micro-cracks, the de-bonding of the filling material from the natural dental tissue, as well as fatigue at the level of their interface. The authors performed a scoping analysis of the nowadays-involved experimental methods, together with a critical review, putting in evidence of their advantages and limits. Based on the developments, they propose a new approach in this sense by involving the electronic speckle pattern interferometry (ESPI)/shearography high-accuracy optical method. They illustrate the advantages of this method in establishment of the elastic modulus, but they also propose a high-accuracy methodology in the estimation of Poisson's ratio. Based on the briefly-illustrated experimental results, one can conclude that ESPI/shearography can become a very useful tool for research, even though it is not a common (nowadays widely applied) method, such as three-point bending or strain gauge methods.

Selected and simplified FDI criteria for assessment of restorations.

OBJECTIVES: Assess the quality of dental restorations with simplified FDI criteria and examine its relationships with other general characteristics of restored teeth. METHODS: The study involved 76 dentists from private and hospital practices. Assessments of successes and failures of previous restorations used a simplified rating with FDI criteria 3 to 8, 11, 12, and 14. The results were examined versus tooth location, number of restored surfaces, type of restoration, and filling material. RESULTS: The dentists examined 4,612 dental restorations, of which 4,185 direct fillings mainly with resin composite materials (2,555). Of all restorations, 2,048 (44.4%) were considered as failures, of which 1,489 had one or two criteria for 'clinically unsatisfactory/poor restoration'. As simplified, the esthetic criterion 'color match' was the most frequent criterion for failure (912 cases). The rate of restoration failures was found associated with the number of surfaces restored and the use of glass-ionomer cement. Results are not comparable with others obtained with original FDI criteria. CONCLUSIONS: Assessing dental restorations with the original FDI criteria leads generally to much more failure statements than practitioners' decisions to reintervene. Though requiring some adjustment (e.g., regarding 'color match'), the simplified assessment proved convenient and amenable to standardization. CLINICAL SIGNIFICANCE: Regardless of the type of practice, selecting, understanding, and optimal interpreting of FDI criteria for failure is essential to help practitioners faced with daily dilemmas of replacement vs. repair of failed dental restorations. Standardization of simplified criteria is desirable to help comparing research data.

The effect of filling technique on the cuspal strain, polymerization shrinkage stress, enamel crack formation and depth of cure of restored molars.

OBJECTIVE: Evaluate the effect of different restorative filling techniques on the residual shrinkage stress (ShrS), cuspal strain (CS), depth of cure (DC), and enamel crack formation (Ec) in molars with MOD restorations. METHODS: Post-gel shrinkage, elastic modulus, compressive and diametral tensile strength of the Filtek One Bulk Fill composite were calculated. Sixty molars with MOD preparations were restored using four filling techniques: Bulk; Horizontal; Oblique; Natural enamel and dentin substitution (NEDS) technique. CS was measured using a strain gauge (n = 10). The DC (n = 5) was measured using Knoop hardness. Shrinkage stress/strain was analyzed using 3D finite element analysis. The Ec analysis was carried out by transillumination. Two-way ANOVA with repeated measures and Tukey's HSD test (α = 0.05) was performed for the CS data. Two-Way ANOVA and Tukey's HSD test was performed for the DC data (α = 0.05). RESULTS: CS was higher at the lingual cusp for the horizontal and NEDS technique. No statistical difference was found between the buccal and lingual CS values for the Bulk (p = 0.367) or Oblique techniques (p = 0.192). CS values were lower for the Bulk. More enamel cracks were found for the Bulk. DC was lower at 4 mm regardless the filling technique. The Horizontal showed the highest ShrS values. The Bulk generated the lower ShrS values. SIGNIFICANCE: A Bulk technique caused the lowest shrinkage stress/strain. An Oblique technique yielded the best balance between stress, strain and crack formation. NEDS technique is a good alternative to decrease the number of increments while maintaining the stress levels nearby the Oblique technique.

Influence of the Polymerization Modes on the Methacrylic Acid Release from Dental Light-Cured Materials-In Vitro Study.

The study focuses on the problem of lowering the pH around a composite filling concerning the polymerization modes and methacrylic acid release, which may affect not only the oral health but also the whole organism. A total of 90 specimens (30 of each: Filtek Bulk Fill, Evetric and Riva LC) were placed in 90 sterile hermetic polyethene containers with saline and incubated at 37 °C. Ten samples of each material were light-cured for 40 s with one of the three curing modes: full power mode (FPM), ramping mode (RM) and pulse mode (PM). The pH and methacrylic acid release evaluation were performed at the following time points: after 2 h and after 3, 7, 21 and 42 days from the specimen preparation. Regardless of light-curing mode, all used materials were characterized by a gradual elevation in methacrylic acid concentration. Only for Filtek Bulk Fill, increased methacrylic acid release was closely associated with lower pH. The choice of the polymerization mode has no significant influence on the methacrylic acid release. However, further research about composite light-curing is necessary to create the procedure algorithm, reducing the local and systemic complications associated with composite fillings.

Hydrophobically Modified Isosorbide Dimethacrylates as a Bisphenol-A (BPA)-Free Dental Filling Material.

A series of bio-based hydrophobically modified isosorbide dimethacrylates, with para-, meta-, and ortho- benzoate aromatic spacers (ISBGBMA), are synthesized, characterized, and evaluated as potential dental restorative resins. The new monomers, isosorbide 2,5-bis(4-glyceryloxybenzoate) dimethacrylate (ISB4GBMA), isosorbide 2,5-bis(3-glyceryloxybenzoate) dimethacrylate (ISB3GBMA), and isosorbide 2,5-bis(2-glyceryloxybenzoate) dimethacrylate (ISB2GBMA), are mixed with triethylene glycol dimethacrylate (TEGDMA) and photopolymerized. The resulting polymers are evaluated for the degree of monomeric conversion, polymerization shrinkage, water sorption, glass transition temperature, and flexural strength. Isosorbide glycerolate dimethacrylate (ISDGMA) is synthesized, and Bisphenol A glycerolate dimethacrylate (BisGMA) is prepared, and both are evaluated as a reference. Poly(ISBGBMA/TEGDMA) series shows lower water sorption (39-44 µg/mm3) over Poly(ISDGMA/TEGDMA) (73 µg/mm3) but higher than Poly(BisGMA/TEGDMA) (26 µg/mm3). Flexural strength is higher for Poly(ISBGBMA/TEGDMA) series (37-45 MPa) over Poly(ISDGMA/TEGDMA) (10 MPa) and less than Poly(BisGMA/TEGDMA) (53 MPa) after immersion in phosphate-buffered saline (DPBS) for 24 h. Poly(ISB2GBMA/TEGDMA) has the highest glass transition temperature at 85 °C, and its monomeric mixture has the lowest viscosity at 0.62 Pa·s, among the (ISBGBMA/TEGDMA) polymers and monomer mixtures. Collectively, this data suggests that the ortho ISBGBMA monomer is a potential bio-based, BPA-free replacement for BisGMA, and could be the focus for future study.

Tunable chitosan-calcium phosphate composites as cell-instructive dental pulp capping agents.

Dental cavities are the most prevalent, preventable disease worldwide providing a need for robust treatment options to restore both the form and function of decaying teeth. Here is a presentation of a possible regenerative pulp capping agent that can serve to restore tooth function while regenerating healthy dentin tissue over a long period of time. To achieve this goal a material needs to crosslink quickly, be structurally rigid, and support the proliferation and differentiation of stem cells contained within the dental pulp. In this study, calcium phosphate nanoparticles were embedded in polymer hydrogels of carboxymethyl-chitosan and a diglycidyl ether. The particle size, surface, and mechanical properties of these materials were characterized. These composites have moduli up to 3 MPa, support the culture of dental pulp stem cells more than 3 weeks and exhibit osteogenic potential even without osteogenic media. These composites demonstrate a promising potential as the next generation of pulp capping materials.