Synthesis, characterization, and evaluation of curcumin-loaded endodontic reparative material.

Curcumin (CUR) is an ancient therapeutic agent with remarkable antimicrobial and anti-inflammatory properties. The purpose of the current study was to synthesize and evaluate a curcumin-based reparative endodontic material to reduce infection and inflammation besides the induction of mineralization during the healing of the dentin-pulp complex. Poly-ɛ-caprolactone (PCL)/gelatin (Gel)/CUR scaffold was synthesized and assessed by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermo-gravimetric analysis (TGA). Agar diffusion test was performed against E. coli, A. baumannii, P. aeruginosa, S. aureus, E. faecalis, and S. mutans. Moreover, proliferative, antioxidative, anti-inflammatory, and calcification properties of these scaffolds on human dental pulp stem cells (hDPSCs) were evaluated. The results showed that PCL/Gel/CUR scaffold had antibacterial effects. Also, these CUR-based scaffolds had significant inhibitory effects on the expression of tumor necrosis factor α and DCF from inflamed hDPSCs (p < 0.05). Moreover, the induction of mineralization in hDPSCs significantly increased after seeding on CUR-based scaffolds (p < 0.05). Based on these findings, the investigated CUR-loaded material was fabricated successfully and provided an appropriate structure for the attachment and proliferation of hDPSCs. It was found that these scaffolds had antimicrobial, antioxidant, and anti-inflammatory characteristics and could induce mineralization in hDPSCs, which is essential for healing and repairing the injured dentin-pulp complex.

Titanium release in peri-implantitis.

OBJECTIVES: The aim of this study was to investigate the titanium (Ti) content of biopsies from patients with severe peri-implantitis or controls without Ti exposure. BACKGROUND: Peri-implantitis is considered to be an infectious disease, but recent studies have shown that Ti can aggravate inflammation in combination with bacterial products. The Ti content of peri-implantitis and periodontitis (controls) tissue is unknown. METHODS: Thirteen patients referred for peri-implantitis and eleven for periodontitis treatment were included in the study. Disease severity was obtained from dental records. Biopsies were taken from both groups and chemically analysed with inductively coupled plasma mass spectrometry for Ti content. Additionally, two patients with peri-implantitis and two with periodontitis were recruited and their biopsies were analysed microscopically with light microscopy, transmission electron microscopy and scanning electron microscopy with element analysis to investigate the presence of particulate Ti. RESULTS: All patients lost one or more implants despite undergoing peri-implant or treatment. Peri-implantitis tissue contained significantly higher concentrations of Ti than control samples with a mean ± SD of 98.7 ± 85.6 and 1.2 ± 0.9 µg/g, respectively. Particulate metal was identified in peri-implantitis and control biopsies, but element analyses could confirm only the presence of Ti in peri-implantitis tissue. CONCLUSION: We showed that high contents of particulate and submicron Ti were present in peri-implantitis tissue. These high Ti contents in peri-implant mucosa can potentially aggravate inflammation, which might reduce the prognosis of treatment interventions.

Amoxicillin-loaded electrospun nanocomposite membranes for dental applications.

Electrospun nanocomposite matrices based on poly(ε-caprolactone) (PCL), nano-hydroxyapatite (nHAp) and amoxicillin (AMX) were designed and investigated for dental applications. nHAp provides good biocompatibility, bioactivity, osteoconductivity, and osteoinductivity properties, and AMX, as antibiotic model, controls and/or reduces bacterial contamination of periodontal defects while enhancing tissue regeneration. A series of polymeric nanocomposites was obtained by varying both the antibiotic and nHAp contents. Fibrous membranes of different compositions were obtained by electrospinning technique, and morphological, thermal, mechanical and surface properties were characterized. The incorporation of AMX seemed to alter the nHAp distribution within the microfibrous matrix. The interaction between AMX and nHAp affected the mechanical performance and modulated the antibiotic release behavior. AMX release profiles presented a burst release that depended on nHAp content, followed by a slow release stage where the drug content (85-100%) was released in 3 weeks. The antimicrobial activity of the AMX-loaded membranes was tested with four bacterial strains depended on both the drug and nHAp contents. Extensive mineralization in simulated body fluid (SBF) was evidenced by SEM/EDX analysis after 21 days. The studied electrospun nanocomposite amoxicillin-loaded membranes could be a promising fibrous-based antibiotic carrier system for dental and tissue engineering applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 966-976, 2017.

Calcium release from experimental dental materials.

The calcium release from calcium phosphate-containing experimental dental restorative materials was examined. The possible correlation of ion release with initial calcium content, solubility and degree of curing (degree of conversion) of examined materials was also investigated. Calcium release was measured with the use of an ion-selective electrode in an aqueous solution. Solubility was established by the weighing method. Raman spectroscopy was applied for the determination of the degree of conversion, while initial calcium content was examined with the use of energy-dispersive spectroscopy. For examined materials, the amount of calcium released was found to be positively correlated with solubility and initial calcium content. It was also found that the degree of conversion does not affect the ability of these experimental composites to release calcium ions.

Rechargeable anticandidal denture material with sustained release in saliva.

OBJECTIVE: Candida-induced denture stomatitis is a common debilitating problem among denture wearers. Previously, we described the fabrication of a new denture material that released antifungal drugs when immersed in phosphate buffered saline. Here, we use more clinically relevant immersion conditions (human saliva; 37°C) and measure miconazole release and bioactivity. MATERIALS AND METHODS: Disks were prepared by grafting PNVP [poly(N-vinyl-2-pyrrolidinone)] onto PMMA [poly(methylmethacrylate)] using plasma initiation (PMMA-g-PNVP) and then loaded with miconazole. Drug-loaded disks were immersed in 10-100% human saliva (1-30 days). Miconazole release was measured and then tested for bioactivity vs miconazole-sensitive and miconazole-resistant Candida isolates. RESULTS: HPLC was used to quantify miconazole levels in saliva. Miconazole-loaded disks released antifungal drug for up to 30 days. Higher drug release was found with higher concentrations of saliva, and, interestingly, miconazole solubility was increased with higher saliva concentrations. The released miconazole retained its anticandidal activity. After immersion, the residual miconazole could be quenched and the disks recharged. Freshly recharged disks displayed the same release kinetics and bioactivity as the original disks. Quenched disks could also be charged with chlorhexidine that displayed anticandidal activity. CONCLUSIONS: These results suggest that PMMA-g-PNVP is a promising new denture material for long-term management of denture stomatitis.

The osseointegration of zirconia dental implants.

Zirconia is currently extensively used in medicine, especially in orthopedic surgery for various joint replacement appliances. Its outstanding mechanical and chemical properties have made it the "material of choice" for various types of prostheses. Its color in particular makes it a favored material to manufacture dental implants. A literature search through Medline enables one to see zirconia's potential but also to point out and identify its weaknesses. The search shows that zirconia is a biocompatible, osteoconductive material that has the ability to osseointegrate. Its strength of bonding to bone depends on the surface structure of the implant. Although interesting, the studies do not allow for the recommendation of the use of zirconia implants in daily practice. The lack of studies examining the chemical and structural composition of zirconia implants does not allow for a "gold standard" to be established in the implant manufacturing process. Randomized clinical trials (RCT) are urgently needed on surface treatments of zirconia implants intended to achieve the best possible osseointegration.

Distribution and excretion of BisGMA in guinea pigs.

Bisphenol-A-glycidyldimethacrylate (BisGMA) is used in many resin-based dental materials. It was shown in vitro that BisGMA was released into the adjacent biophase from such materials during the first days after placement. In this study, the uptake, distribution, and excretion of [(14)C]BisGMA applied via gastric and intravenous administration (at dose levels well above those encountered in dental care) were examined in vivo in guinea pigs to test the hypothesis that BisGMA reaches cytotoxic levels in mammalian tissues. [(14)C]BisGMA was taken up rapidly from the stomach and intestine after gastric administration and was widely distributed in the body following administration by each route. Most [(14)C] was excreted within one day as (14)CO(2). The peak equivalent BisGMA levels in guinea pig tissues examined were at least 1000-fold less than known toxic levels. The peak urine level in guinea pigs that received well in excess of the body-weight-adjusted dose expected in humans was also below known toxic levels. The study therefore did not support the hypothesis.

[Release of fluoride ions into saliva from some dental materials]. / Uwalnianie jonów fluorkowych do sliny z wybranych materialów stomatologicznych.

The aim of the study was to evaluate fluoride release from dental materials: resin composites--Tetric Ceram and Degufill Mineral, fissure sealants--Conseal F and Admira seal, compomer--Freedom and glass-ionomer cement--Vitremer. Release to the patient's unstimulated mixed saliva was studied after treatment with the material. The study group comprised 72 patients and fluoride concentrations were measured with an ion-selective electrode (Orion). The following release of fluoride in decreasing order was found: Vitremer (6.03 microM), Degufill Mineral (2.79 microM), Teric Ceram (2.54 microM), Freedom (2.52 microM), Admira seal (1.85 microM) and Conseal F (1.80 microM).

[Effect in vitro of environmental parameters on the release of fluoride ions from some materials used in dentistry]. / Wplyw parametrów srodowiska na uwalnianie jonów fluorkowych z wybranych materialów stomatologicznych--badania in vitro.

The aim of this in vitro study was to evaluate the influence of calcium ions and pH on fluoride release from selected dental materials. The materials studied included a resin composite (Te-Econom), fissure sealant (Conseal F) and compomer (Freedom). Samples were placed for 7 days in artificial saliva with or without calcium ions and pH ranging from 4.5 to 7.5. Fluoride release from the studied materials was measured with an ion-selective electrode (Orion). The results demonstrate differing effects of calcium concentration and pH on fluoride release. The highest cumulative fluoride release was observed from Freedom and the lowest from Te-Econom. Addition of calcium ions to the medium reduced the release of fluoride.

Electrochemical study on microbiology-related corrosion of metallic dental materials.

Microbiology-related corrosion has been noted in industry for many years. It is widely recognized that microorganisms affect the corrosion of metal and alloys immersed in aqueous environments. Under similar conditions, the effect of bacteria in the oral environment on the corrosion of dental metallic materials remains unknown. The purpose of this study is to investigate the corrosion behavior of dental metallic materials in the presence of Streptococcus mutans and its growth byproducts. Samples were commercially pure titanium (CPT), Ti-6Al-4V (TAV), Ti-Ni (TN), Co-Cr-Mo alloy (CCM), 316L stainless steel (SSL), 17Cr-4Ni PH-type stainless steel (PH), and Ni-Cr alloy (NC). Using Gamry corrosion test system, surfaces were exposed to (1) sterilized Ringer's solution as a control for (2), (2) S. mutans mixed with sterilized Ringer's solution; (3) sterilized tryptic soy broth as a control for (4), and (4) byproducts of S. mutans mixed with sterilized tryptic soy broth. Corrosion parameters (EOCP, ECORR, ICORR, etc.) were corrected for all tested samples. Averaged values of these parameters were statistically analyzed by t-test to identify significant differences. It was concluded that (1) S. mutans reduced the EOCP of CPT, TAV, TN, and SSL, and the byproducts of S. mutans reduced the EOCP of TAV, TN, SSL, and PH. (2) S. mutans increased the ICORR of PH, and byproducts of S. mutans increased the ICORR of all the samples. (3) S. mutans reduced the ECORR of CPT, TAV and TN, and the byproducts of S. mutans reduced the ECORR of TN, SSL, PH, and NC. (4) S. mutans increased the IPASS of CPT, and the byproducts of S. mutans increased the IPASS of CPT, PH, and NC.

Permeability of medical gloves to mono- and dimethacrylate monomers in dental restorative materials.

Dental personnel manually handle methacrylate-based restorative materials, which can cause skin irritation and allergies. The protection given by different types of medical gloves is not well known. Breakthrough time (BTT, min) was used as a measure of protection according to a European standard, using 2 test mixtures consisting of respectively 3 and 5 monomers. Fourteen gloves representing natural rubber latex, synthetic rubber, and synthetic polymeric material were tested. The BTT ranged from some minutes to more than 2 hrs for the 4 monomers with a molecular mass less than 300. The longest protection was recorded for Nitra Touch (nitrile rubber), Tactylon (synthetic rubber), and Metin (PVC).

A study of titanium release into body organs following the insertion of single threaded screw implants into the mandibles of sheep.

BACKGROUND: Titanium is generally considered a safe metal to use in implantation but some studies have suggested that particulate titanium may cause health problems either at the site overlying the implant or in distant organs, particularly after frictional wear of a medical prosthesis. It was the purpose of this investigation to study the levels of dissemination of titanium from threaded screw type implants following placement of single implants in sheep mandibles. METHOD: Twelve sheep were implanted with a single 10x3.75mm self-tapping implant for time intervals of one, four and eight to 12 weeks. Four unoperated sheep served as controls. Regional lymph nodes, lungs, spleens and livers were dissected, frozen and subsequently analysed by Graphite Furnace Atomic Absorption Spectroscopy. RESULTS: Results associated with successful implants showed no statistically significant different levels of titanium in any organ compared to controls, although some minor elevations in titanium levels within the lungs and regional lymph nodes were noted. Two implants failed to integrate and these showed higher levels of titanium in the lungs (2.2-3.8 times the mean of the controls) and regional lymph nodes (7-9.4 times the levels in controls). CONCLUSIONS: Debris from a single implant insertion is at such a low level that it is unlikely to pose a health problem. Even though the number of failed implants was low, multiple failed implants may result in considerably more titanium release which can track through the regional lymph nodes. Results suggest that sheep would be an excellent model for following biological changes associated with successful and failed implants and the effect this may have on titanium release.

Toxicokinetic of HEMA in guinea pigs.

OBJECTIVE: Unconverted 2-hydroxyethylmethacrylate (HEMA) can be released from dental resin materials and can enter the body in humans. In the present study the uptake, distribution and excretion of 14C-HEMA applied via different routes were examined in vivo in guinea pigs. METHODS: HEMA (0.02 mmol/kg bw labelled with a tracer dose 14C-HEMA 0.3 Bq/g bw) was administered by gastric tube or by subcutaneous injection. Urine, feces, and exhaled carbon dioxide were collected for 24 h after administration. Guinea pigs were killed 24 h after the beginning of the experiment and various organs removed and 14C radioactivity measured. RESULTS: Low fecal 14C levels (about 2% of the dose) and urinary levels of about 15% after 24 h were noted with either route of administration. Direct measurement of exhaled CO(2) showed that about 70% of the dose left the body via the lungs. Two pathways for the metabolism of 14C-HEMA can be described. It is likely that 14C-pyruvate is formed in vivo resulting in the formation of toxic 14C-HEMA intermediates. 14C-HEMA was taken up rapidly from the stomach and small intestine after gastric administration and was widely distributed in the body following administration by each of the routes. CONCLUSIONS: Clearance from most tissues following gastric and intradermal administration was essentially complete within one day. The peak HEMA levels in all tissues examined after 24 h were at least onemillion-fold less than known toxic levels.

Comparative in vitro study of apically extruded material after four different root canal Instrumentation techniques.

Forty newly extracted human upper central incisors were submitted to root canal instrumentation 1 mm from the apex using four different techniques: standard, step-preparation, crown-down, and ultrasound, with distilled and deionized water as the irrigating solution. The extrusion product was collected into a collecting device constructed for this purpose. Extrusion was calculated by the determination of the mass of extruded material. The step-preparation technique caused a larger amount of extrusion than the standard technique, which in turn caused greater extrusion than the crown-down and ultrasound techniques. All techniques used caused extrusion of material beyond the apical foramen.

Bioavailability of components of resin-based materials which are applied to teeth.

Chemical components of many materials used in dental practice can move into the local biophase, where they can have beneficial or adverse effects. The strongest indirect evidence that components of resin-based materials used in dentistry can move into the biophase are the many reports of allergic dermatitis in dental personnel. Direct measurement of component release has shown that triethylene glycol dimethacrylate (TEGDMA), hydroxyethyl methacrylate (HEMA), and, in the case of some orthodontic cements, bis-glycidyl methacrylate and benzoyl peroxide can move into an aqueous medium from a range of resin-based materials which are applied to teeth as part of oral care. In the case of resin composite restorations, HEMA and TEGDMA are available in microgram quantities via the salivary surface in the minutes and hours after clinical placement and via dentin and pulp in the hours and days after placement. Fortunately, moderate thickness of dentin protects pulp tissue against local toxicity. There are no data which suggest that systemic toxicity is a risk with any of these materials. There are some case reports of allergic responses to the monomers in patients, but the incidence of such responses appears at present to be much lower than that in dental personnel.

Atividade antimicrobiana dos forradores: avaliação de materiais empregados como protetores do complexo dentina-polpa / Anti-mycrobiologic activity of pulp-capping material: evaluation of the materials used as protectors of the dentin-pulp complex

A atividade antimicrobiana de doze produtos empregados como protetores do complexo dentina-polpa (cimentos de hidróxido de cálcio, fosfato de zinco, óxido de zinco e eugenol, ionômero de vidro e policarboxilato, além do hidróxido de cálcio P.A. e resinoso) foi avaliada "in vitro" frente a 5 cepas de Streptococcus mutans e Staphylococcus aureus ATCC 25923. Os testes de sensibilidade foram realizados pela técnica de ágar difusão. Os resultados revelaram que: 1) Os cimentos de óxido de zinco e eugenol e o hidróxido de cálcio P.A. mostram maior atividade antimicrobiana. 2) Somente o cimento Timeline não demonstrou atividade antimicrobiana. 3) Os cimentos contendo Ca(HO)² em sua composição mostraram moderada atividade antimicrobiana sobre o Streptococcus mutans, o mesmo ocorrendo com o Durelon. 4) Os cimentos de ionômero de vidro (Shofu Lining Cement e Vidrion F), bem como o New Zinc e Lee Smith mostraram pouca atividade antimicrobiana quando comparados aos demais produtos