The aim of this review was to assess the effectiveness of different direct pulp-capping (DPC) materials for human pulp-exposed teeth. An electronic search was performed on 20 February 2018. Long-term clinical and radiographic evaluations of the effectiveness of different DPC materials for use on human pulp-exposed teeth were included. Risk-of-bias assessment and data extraction were performed. From the 496 identified articles, 15 met the eligibility criteria. Among the studies included in those articles, a total of 1,322 teeth were treated with 12 types of DPC materials, and 1,136 teeth were evaluated at a final follow-up examination. For mineral trioxide aggregate (MTA) and calcium hydroxide (CH), the number of included studies, the number of treated teeth, and the mean follow-up period of studies were almost equal, and the success rates of MTA was superior to CH. Therefore, MTA is likely to be a more effective and predictable material for DPC compared to CH. However, the results were based on the included studies, which were all judged to have a high risk of bias. Therefore, more long-term clinical and radiographic studies designed with lower risk of bias are needed. Moreover, the other 10 materials were only investigated by a small number of studies; therefore, further studies are required.

This study investigated the stability of mini-screws placed in the median palate. The study included 25 patients (7 males, 18 females; mean age, 23.4 ± 5.6 years; age range, 15.0-34.5 years) who had mini-screws placed during orthodontic treatment at Nihon University School of Dentistry Dental Hospital. Mini-screws (diameter, 2.0 mm; length, 9.0 mm) were placed in the median palatal region; the first screw was inserted mesiodistally at the distal contact of the maxillary first molar, and the second screw was placed 6-9 mm mesial to the first screw. Immediately after placement, the placement sites were carefully examined with cone-beam computed tomography and a Periotest device. Screw stability was not related to perforation of the nasal cavity, patient age, or patient sex. The success rate was significantly higher in patients with screw-suture distances of 1.5-2.7 mm than in those with distances of 0-1.4 mm. Moreover, mini-screws could be stabilized when palatal cortical bone thickness was ≥1.5 mm. The success rate was significantly higher in the group with insertion depths of ≥4.5 mm. These results indicate that primary stability of mini-screws requires sufficient cortical bone thickness, insertion depth, and screw-suture distance.

Minimally invasive treatment protocols may leave a residual layer of carious dentin, which requires treatment for the inhibition of bacterial growth beneath restorations. We aimed to examine the in vivo effect of silver diammine fluoride (SDF) and SDF + potassium iodide (KI) application on bacteria present in deep carious lesions. We studied the in vivo efficacy in five patients, each of which had five carious lesions. Dentin samples taken before and after treatment were subjected to microbial analyses. Following treatment with SDF, the median colony-forming unit (CFU) counts per mg of dentin reduced from 9 × 10⁵ to 1.6 × 10² (P < 0.05), and following that with SDF + KI, the counts decreased from 2.9 × 10⁵ to 9.2 × 10 (P < 0.05). The use of chlorhexidine gluconate (CHX) reduced CFU counts from 1.1 × 10⁵ to 4.8 × 10² (P < 0.05). In four of the five patients, no CFUs were found on mitis salivarius-bacitracin agar with respect to SDF or SDF + KI application. For CHX, the median CFU count before treatment was 1.6 × 10³ and that after treatment was 1.1 × 10². SDF completely inhibited mutans streptococci growth in four of the five patients, while the growth of anaerobes was not completely inhibited.

High-magnitude mechanical strain inhibits bone nodule formation by reducing expression of bone morphogenetic protein-2 (BMP-2), Runt-related transcription factor 2 (Runx2), and muscle segment homeobox 2 (Msx2). Mechanical strain also induces production of proinflammatory factor prostaglandin E₂ (PGE₂) by osteoblasts. We measured the effect of mechanical strain-induced PGE₂ production on bone nodule formation and expression levels of bone formation-related factors. Osteoblast-like cells isolated from fetal rat calvariae were loaded with 18% cyclic tension force (TF) for 48 h in the presence or absence of NS-398, a selective inhibitor of cyclooxygenase-2. To investigate the effect of TF-induced PGE₂ on bone formation, bone nodule area on day 21 was measured by von Kossa staining. BMP-2, Runx2, and Msx2 expression levels were examined at 1 day after TF loading. Bone nodule formation was significantly inhibited by TF but was restored to control level by PGE₂ inhibition. Furthermore, TF loading-induced reductions in expressions of these factors were restored to control level by PGE₂ suppression. These results indicate that PGE₂ production induced by high-magnitude mechanical strain inhibits bone nodule formation by reducing expression levels of bone formation-related factors.

Transplantation of mesenchymal stem cells (MSCs) has been extensively studied in the field of regenerative medicine. Bone regeneration is achieved via the interaction of osteoblasts and osteoclasts. However, the influence of MSCs on osteoclasts is unknown. The purpose of this study was to investigate the effect of MSCs on the expression of genes for osteoclast differentiation factors using qPCR after indirect co-culture of MSCs and RAW264 cells. The numbers of osteoclasts after addition of soluble receptor activator of nuclear factor kappa B (NF-κB) ligand (sRANKL) were also compared. Expression of osteoprotegerin (OPG) by MSCs was significantly elevated in co-culture over time. The differentiation of RAW264 cells into mature osteoclasts following addition of sRANKL was significantly inhibited by co-culture with MSCs. Expression of RANK, colony stimulating factor 1 receptor, NF-κB, and nuclear factor of activated T-cell cytoplasmic 1 in RAW264 cells was significantly inhibited by co-culture with MSCs. Expression of OPG protein was higher in co-culture with RAW264 cells than in MSCs alone, and the expression level was clearly higher than that of RANKL. MSCs appeared to inhibit osteoclast differentiation via expression of OPG.

Assessment and treatment of masticatory myofascial pain syndrome (MPS) are not standardized and remain controversial. We examined whether muscle hardness was useful for evaluating masticatory MPS and analyzed the effectiveness of treatments such as stretching and massage (SM) and trigger point injection (TPI). Twenty healthy volunteers and 20 MPS patients were enrolled. MPS patients were divided into TPI and SM treatment groups. Hardness of masticatory muscle with a taut band (TB) and change in hardness were evaluated after SM and TPI treatments. Hardness values were significantly higher in muscle including a TB (TB point) than in the muscle of healthy controls. Visual analogue scale scores were significantly lower after SM and TPI treatments, and hardness of the TB point was significantly lower after SM but not after TPI. These results suggest that measurement of muscle hardness, including the TB, is useful for evaluating masticatory MPS. However, TPI analgesia might not be caused by change in muscle hardness. The mechanisms underlying the effects of SM and TPI on reducing pain in MPS may differ and thus warrant further research.

This in vitro study assessed morphological changes and efficiency of reciprocating files after multiple uses. Sixty standardized Endo Training Blocks and 10 ReciprocR25 files were selected (six blocks for each file). Each file was its own control (before use vs. after each instrumentation). The instruments were used according to the manufacturer’s instructions, and scanning electron microscopy was used to observe fatigue cracks, metal strips/metal flash, pitting, fretting, debris, disruption of the cutting edge, and plastic deformations after each instrumentation. The presence of seven wear variables was scored semiquantitatively by viewing micrographs collected before and after use. The prepared areas in resin blocks were calculated and compared by using AutoCAD software. The control group had significantly lower values for all wear variables except fretting and plastic deformation. The presence of fatigue cracks and metal strips/metal flash significantly differed between unused instruments and instruments used four or five times, in all observed sections. The area of instrumented Endo Training Blocks significantly differed in relation to the number of instrument uses. The Reciproc files wore progressively, and repeated use affected their shaping efficiency in simulated canals.

The purpose of this study was to investigate the effects of vitamin D in rat models of chronic obstructive pulmonary disease (COPD) and periodontitis. Animals with both periodontitis and COPD, or with periodontitis only, were established. Once the animal model was established, experimental groups received intraperitoneal injections of 25-hydroxyvitamin D3 (25-OHD3) for 8 weeks, while control groups received refined peanut oil. After sacrifice, inflammatory status was examined in terms of the serum levels of receptor activator of the nuclear factor κB ligand (RANKL), tumor necrosis factor alpha (TNF-α) and interleukins (IL-1 and IL-10), as well as alveolar bone loss, forced expiratory volume (0.20) (FEV 0.20), and the ratio of FEV0.2 to forced vital capacity. The results showed that 25-OHD3 treatment significantly alleviated inflammation by decreasing the serum levels of RANKL, TNF-α and IL-1 and increasing that of IL-10, while reducing alveolar bone loss and slightly improving lung function. These findings suggest that vitamin D supplementation could be a new clinical approach for the treatment of COPD and periodontitis.

The present study aimed to evaluate the performance of cone-beam computed tomography (CBCT) in assessing periodontal bone loss. If effective, CBCT could potentially be a more comfortable and accurate way to evaluate this disease. One hundred and eighty tooth sites from 13 patients were included. Clinical attachment level (CAL) was measured, then CBCT images were acquired prior to periodontal surgery. Three periodontists measured the distance between the cemento-enamel junction and alveolar bone crest at the mesio-buccal, mid-buccal, disto-buccal, mesio-lingual/palatal, mid-lingual/palatal, and disto-lingual/palatal sites. Comparisons of measurements were made among three methods. Inter-observer and intra-observer variances were also analyzed. Statistically significant differences were found between CBCT and CAL + 2.04 mm (P = 0.000), as well as intra-surgical evaluation (P = 0.001). All sites showed differences in CBCT versus intra-surgical measurement and versus CAL + 2.04 comparisons, except the buccal sites (P = 0.187 and 0.147, respectively). This study indicates that the results of CBCT do not agree with results of intra-surgical measurement. As a result, CBCT should be used with caution and only when necessary, to avoid radiation hazards.

The aim of this study was to evaluate the effects of a fiberotomy-like procedure using Er:YAG laser irradiation on the velocity of orthodontic tooth movement. To produce experimental tooth movement in rats, orthodontic force was applied to the upper first molars with a nickel-titanium closed coil. The right molars were irradiated with an Er:YAG laser while the non-irradiated left molars were used as controls. The rats were sacrificed at 4 weeks after the start of tooth movement and the distance between the mesial side of the second molar and the distal side of the upper first molar was measured on CT images. The amount of tooth movement was significantly greater in the irradiation group than in the control group. The TRAP-positive nuclei count at the pressure site was higher in the laser-irradiation group than in the control group. Expression of RANKL and ALP was higher at the mesial-coronal pressure site in the laser-irradiation group than in the control group. In addition, expression of OPG was higher at the pressure site in the control group than in the laser-irradiation group. These results suggest that a fiberotomy-like procedure using an Er:YAG laser stimulates osteoclasts and osteoblasts and may promote bone metabolism in the context of experimental tooth movement.

The aim of this study was to investigate the effect of prolonged release of iloprost, a prostacyclin analog, on angiogenesis and dental pulp healing in a rat model of mechanical pulp exposure. The profile of iloprost release from poly (lactic-co-glycolic) acid (PLGA) microspheres was evaluated, and expression of vascular endothelial growth factor (VEGF) mRNA was determined. The molars of rats were subjected to mechanical pulp exposure and 5 different forms of treatment: Ca(OH)₂, PLGA (blank), iloprost, and iloprost/PLGA. Blood flow was determined at 0, 3, and 7 days using laser Doppler flowmetry. After 30 days, the tooth specimens were collected, and subjected to micro-CT and immunohistological analysis. The results showed that iloprost release from the microspheres was prolonged for 4 days, and that the treatment increased tooth blood flow for up to 7 days. At 30 days, an increase of mineralized tissue formation and dentin bridge formation was observed in the iloprost and iloprost/PLGA microsphere groups. VEGF expression was significantly increased in the iloprost/PLGA microsphere group relative to the other groups. In conclusion, this PLGA microsphere iloprost delivery system significantly increased dental pulp blood flow in a prolonged manner and increased tertiary dentin formation in this rat pulp injury model. Prolonged prostacyclin release could be a potentially useful approach for regeneration of dental pulp.

This study evaluated the long-term effectiveness of intra-articular temporomandibular joint arthrocentesis for patients with osteoarthritis and compared arthrocentesis/lavage alone with arthrocentesis/lavage and injected hyaluronic acid. Forty patients met the inclusion criteria, and 37 completed long-term follow-up (approximately 4 years). The patients were randomly allocated to two groups: arthrocentesis with lavage alone (A-group, n = 17) or combined with hyaluronic acid treatment (AS-group, n = 20). Standard two-needle arthrocentesis was performed. Pain and joint sounds were measured at baseline and approximately 4 years after treatment. Reported pain, as indicated by visual analogue scale (VAS) score, significantly decreased from baseline to the final follow-up examination in both groups. Mean VAS score decreased from 64 to 16 (P < 0.001) in the A-group and from 63 to 25 (P < 0.001) in the AS-group. Average maximum incisor opening increased significantly in both groups but did not significantly differ between groups (P = 0.223). Joint sounds did not significantly improve within groups (A-group, P = 0.495; AS-group, P = 0.236). Both methods resulted in significant long-term improvements in pain and jaw function.

This study evaluated the microhardness of four types of low-shrinkage composite resins and two types of universal composite resins with either 12 or 16 J/cm² light power energy. Three disks were made for each group (n = 3) for a total of 36 specimens. The specimens were prepared by condensing the composite resin into a circular copper mold (diameter: 6 mm; height: 2 mm) and polymerizing with 700 mW/cm² light power density. The microhardness values of the resin specimens were measured using a Vickers hardness tester after different storage durations. Z250 and Clearfil Majesty Posterior composites showed softer subsurfaces when comparing the 24 h samples for all six types. Conversely, Kalore GC and Admira (AD) composites showed harder subsurfaces during the 24 h samples. All the composite resins showed significant differences (P < 0.05) in microhardness values at one of the aging times when they were polymerized with either 12 or 16 J/cm² light power energy. Composite resin AD had a higher microhardness value after polymerization with 12 J/cm² than with 16 J/cm². The results indicated that low-shrinkage composite resins have better subsurface characteristics, and the light power energy of 16 J/cm² is better for the polymerization of most composites.

This study assessed the impact of chronic unpredictable mild stress (CUMS) on the structure of mouse salivary glands and the role of musk in alleviating this impact. Forty male albino mice were distributed equally into four groups; control (untreated), CUMS (exposed to CUMS for 4 weeks), CUMS+fluoxetine (FLU) (exposed to CUMS then treated with FLU, CUMS+musk (exposed to CUMS then treated with musk). Behavioral changes and serum corticosterone levels were assessed at the end of the experiment. The submandibular and parotid glands were dissected out and processed for histopathological and immunohistochemical examination using antibodies against alpha smooth muscle actin (ASMA) and brain-derived neurotropic factor (BDNF). Exposure to CUMS significantly (P < 0.001) increased the serum corticosterone level and induced depression. CUMS also induced vacuolation in acinar cells along with a significant (P < 0.001) reduction of ASMA immunoexpression, indicating an effect on myoepithelial cells, and a significant (P < 0.001) increase of BDNF expression in the gland ductal system. Both FLU and musk alleviated the CUMS-induced behavioral, biochemical and histopathological changes in the salivary glands. In conclusion, musk ameliorates stress-induced structural changes in mouse salivary glands. This effect might be mediated through up-regulation of BDNF secretion by the glands.

The bleaching efficacy of common bleaching agents and deionized water treated with non-thermal atmospheric pressure plasma in the pulp chamber for nonvital tooth bleaching was evaluated. A total of 120 extracted human maxillary first incisors were stained using human blood. Teeth were randomly divided into eight groups (n = 15). In the first four groups, teeth were bleached using 35% hydrogen peroxide gel, 37% carbamide peroxide gel, 2:1 (w/v) sodium perborate paste, and deionized water for 30 min. In the remaining groups, bleaching agents were treated with non-thermal atmospheric plasma for 5 min inside the pulp chamber. Overall color changes (∆E) were determined using Commission Internationale de L’Eclairage Lab Colour System. The plasma-assisted tooth bleaching has not increased tooth temperature beyond 37°C. Bleaching efficacies of bleaching agents were significantly improved when treated with non-thermal atmospheric plasma compared to their application (P < 0.05). A remarkable bleaching effect was obtained when bleaching agents were substituted with water and when treated with non-thermal atmospheric plasma. Non-thermal atmospheric plasma treatment could be a novel tool for activation of bleaching agents in the pulp chamber for nonvital tooth bleaching procedure. Moreover, water could be used as a novel bleaching agent when treated with the non-thermal atmospheric plasma to eliminate possible risks which might arise from peroxide-containing agents.

Phosphatidylserine (PS)―normally present on the inner leaflet of the plasma membrane―translocates to the outer leaflet at an early stage of apoptosis. PS-containing liposomes (PSLs) can mimic the effect of apoptotic cells in inducing the secretion of prostaglandin E₂ from phagocytes and inhibiting the maturation of dendritic cells and osteoclast precursors. The present study attempted to evaluate the effect of calcium phosphate (in the form of hydroxyapatite [HAP]) in the presence or absence of PSLs for repair of rat calvarial bone defects. The defects, each 5 mm in diameter, were created in the calvaria parietal bone of 8-week-old Wistar rats and subjected to one of the following treatments: no augmentation (Sham), HAP alone, or a mixture of HAP and PSL (HAP+PSL). Micro-computed tomography data showed that the HAP+PSL complexes promoted greater bone regeneration in comparison with either the Sham procedure or HAP alone at 4 and 8 weeks after implantation. The regeneration of calvarial bone defects induced by PSLs was mediated partly through upregulation of the osteogenic marker Alkaline Phosphatase, Type I collagen, osteocalcin, Runx2, and Osterix mRNAs. These data are the first to show that PSLs can influence bone regeneration by regulating osteoblast differentiation.

This study was to investigate the influences of habitual mouth breathing on memory and learning ability during the growth period. At age 5 weeks, the experimental rats were subjected to surgery to close completely one side of the nasal cavity. An 8-arm radial maze was used to evaluate memory and learning ability at age 7, 11, and 15 weeks. Moreover, the brain was extracted at age 7, 11, and 15 weeks, and subjected to histomorphometric examination for the distribution and number of pyramidal cells in the hippocampal CA1 and CA3 regions after Nissl staining. The trial time to accomplish each task was significantly longer in the experimental group than in the control group throughout the experimental period. The number of pyramidal cells was significantly less in the experimental rats than in controls in both the CA1 and CA3 regions for the entire experimental period. Thus, the functional deterioration of the respiratory system during the growth phase exerts a substantial effect on the growth and development of the central nervous system.

This study investigated the effect of fluoride mouthrinses on bonding of a one-step self-etch adhesive to bovine root dentin. Application of a NaF solution (0, 450, 900, or 9,000 ppm) to bovine root dentin surfaces was performed for 30 s (immediate) or before bonding of an all-in-one adhesive. Microtensile bond strength (µTBS) testing and scanning electron microscopic (SEM) observation of the acid-base resistance zone (ABRZ) were performed. µTBS values and calculated ABRZ areas were analyzed by using two-way ANOVA and the t-test with Bonferroni correction. The significance level was set at P = 0.05 (n = 30). Fracture mode was analyzed with the Mann-Whitney U test with Bonferroni correction. The significance level set at P = 0.00178 (n = 30). µTBS did not significantly differ between the control, 450 ppm F, and 900 ppm F specimens (P > 0.05) but was significantly lower in 9,000 ppm F specimens (P < 0.05). SEM showed a significant increase in acid resistance at the adhesive-dentin interface, including the ABRZ, after fluoride application.

The aim of this study was to investigate the association between the presence of gingivitis estimated using the salivary level of lactate dehydrogenase (LD) and related factors in young Japanese adults. Data from 1,915 participants (21.4 ± 2.5 years) were analyzed. Unstimulated saliva was collected from each participant and the salivary LD level was evaluated using a commercially available test kit with an integer scale ranging from 1 to 10. Gingivitis was defined as the LD level of ≥8. The number of permanent teeth, the simplified oral hygiene index (OHI-S), the presence of partially erupted molars and body mass index were recorded. Additionally, participants answered a questionnaire. The percentage of male participants, the number of permanent teeth, the OHI-S and the presence of partially erupted molars were higher, whereas the proportion receiving dental check-ups was lower in the gingivitis group (n = 88, 4.6%) than in the healthy group. Logistic regression analysis showed that gingivitis was significantly associated with OHI-S (OR: 2.68, 95% CI: 1.94-3.69) and receiving dental checkups (OR: 0.31, 95% CI: 0.10-0.99). The present findings indicated that the OHI-S and receiving dental checkups were significantly associated with gingivitis, as assessed by the salivary LD level, in this cohort.

Denture plaque is a biofilm composed of various microorganisms aggregated with saliva. Various denture cleansers and cleaning apparatuses have been developed and studied. However, the optimum water temperature for denture cleaning is unknown. Therefore, the present study investigated the effects of water temperature during ultrasonic denture cleaning. In vitro, resin disks with artificial Candida albicans biofilm were pressed onto Candida GE media after ultrasonic cleaning with water at different temperatures for 5 min. The media were subsequently cultured at 37°C for 24 h. The colonies formed were observed and colony areas were quantified using ImageJ software (US National Institutes of Health, Bethesda, MD, USA). In situ, the bacterial count and degree of cleanliness on the tissue surface of maxillary dentures were measured before and after ultrasonic cleaning with water at different temperatures for 5 min. Changes in bacterial counts and cleanliness were calculated for each temperature. The ratio of the area occupied by bacterial colonies in vitro and reduction rates in situ after cleaning with warm water were markedly less than those observed after cleaning with cold water. Therefore, ultrasonic denture cleaning with warm water is more effective.

Bright light stimulation of the eye activates trigeminal subnucleus caudalis (Vc) neurons in rats. Sensory information is conveyed to the Vc via the trigeminal ganglion (TG). Thus, it is likely that TG neurons respond to photic stimulation and are involved in photic hypersensitivity. However, the mechanisms underlying this process are unclear. Therefore, the hypothesis in this study is bright light stimulation enhances the excitability of TG neurons involved in photic hypersensitivity. Expressions of calcitonin gene-related peptide (CGRP) and neuronal nitric oxide synthase (nNOS) were significantly higher in TG neurons from 5 min to 12 h after photic stimulation of the eye. Phosphorylation of extracellular signal-regulated kinase1/2 (pERK1/2) was enhanced in TG neurons within 5 min after photic stimulation, while pERK1/2 immunoreactivity in satellite glial cells (SGCs) persisted for more than 12 h after the stimulus. Activation of SGCs was observed from 5 min to 2 h. Expression of CGRP, nNOS, and pERK1/2 was observed in small and medium TG neurons, and activation of SGCs and pERK1/2-immunoreactive SGCs encircling large TG neurons was accelerated after stimulation. These results suggest that upregulation of CGRP, nNOS, and pERK1/2 within the TG is involved in photic hypersensitivity.

This was a cross-sectional study with 550 students aged 17-19 years old. Gingival biotype (GB) was classified as thin, thick, and mixed based on visual inspection. Biotypes were associated with anatomical parameters from the anterior teeth, including probing depth, keratinized gingiva (KG), and gingival attachment (GA). Upper lip distance, facial thirds, tooth shape, gingival recessions, and gummy smile (GS) were also measured. Other variables included sex, age, dietary intake, and oral hygiene habits. Prevalence of thin, thick, and mixed biotypes was 68.4%, 19%, and 12.5%, respectively. Recessions occurred most often in those with thin biotypes. GS was more often seen in men with thin biotypes and in women with thick biotypes. There was a relationship between thin biotypes and oval teeth, and between thick biotypes and square teeth. The lower facial third was larger in thin biotypes. Thin biotypes were also related to larger canines, larger lateral and central incisors, and less KG and GA. Conversely, thick biotypes were associated with shorter teeth and with more KG and GA. Dietary intake and dental hygienic were not significantly associated with GB. Morphologic and phenotypic characterization of GBs can be relevant when planning and performing common dental procedures (e.g., prosthetics, implants, and orthodontics).

Needle-stick and sharps injuries (NSIs) can happen even when dental health care workers (DHCWs) act in compliance with standard precautions to prevent transmitting blood-borne infections. The objective of this study was to investigate causes of NSIs that had occurred at a dental specialty university hospital during the past 12 academic years. A total of 215 NSIs were reported during the investigation period, and NSIs ascribed to female DHCWs (n = 148; 68.8%) were significantly (P < 0.05) more common than those ascribed to male DHCWs (n = 67; 31.2%). One hundred twenty-six NSIs (58.6%) were caused by DHCWs with little experience (P < 0.05), and 37 of those (17.2% of the total) were ascribed to undergraduate students during clinical training (P < 0.05). The NSIs occurred both during treatment (n = 119; 55.3%) and during cleaning up used devices (n = 89; 41.4%). The NSIs at the dental hospital occurred with a probability of 0.004% of total therapeutic opportunities. Prevention of NSIs should be the responsibility of dental students and DHCWs, and should be a part of education about infection control to prevent the nosocomial transmission of blood-borne pathogens.

This study evaluated the biocompatibility of a new silicone-based sealer (GuttaFlow Bioseal) in rat subcutaneous tissue and compared the results with those for GuttaFlow2 and AH Plus. Each of 16 Wistar rats received four subcutaneous tissue implants, namely, GuttaFlow Bioseal, GuttaFlow2, AH Plus, and one empty polyethylene tube. Eight rats were euthanized at day 8 and the remaining eight at day 30. Histological sections were stained with haematoxylin and eosin and analysed with a light microscope. Scores were established for inflammatory reaction, macrophage infiltrate, thickness of the fibrous capsule, and vascular changes. Differences between groups were assessed by using the Friedman test with Bonferroni correction. Histological analysis showed that GuttaFlow Bioseal had the lowest inflammatory reaction of all tested sealers at day 8. At day 30, the silicone-based sealers had similar inflammation profiles, but inflammation scores were nonsignificantly higher for AH Plus than for the negative control. The inflammatory reaction decreased from day 8 to day 30 in all sealers. GuttaFlow Bioseal had the most macrophage infiltrate. Under the present experimental conditions, GuttaFlow Bioseal induced limited inflammatory reactions at days 8 and 30, and initial inflammatory reactions to GuttaFlow2 and AH Plus subsided within 30 days. All tested sealers exhibited satisfactory biocompatibility at day 30 after subcutaneous implantation.

This study evaluated the light intensity of light-emitting diode (LED) units and the effects of five laboratory polymerization units on hardness and flexural strength. Two indirect composite materials (Cesead N and Solidex Hardura) were polymerized with five units (α-Light II, Hyper LII, LED Cure Master, Twinkle LED, and α-Light V). The light intensity of the devices was measured with a spectroradiometer. After light exposure, Knoop hardness number, flexural strength, and elastic modulus were determined. Evaluation of light intensity, using a wavelength range of 400 to 500 nm, revealed that the α-Light V and Hyper LII units had the highest light intensity. For the top surface of the two composites, the Knoop hardness number was significantly higher for the α-Light V and Hyper LII. For the two composite materials, flexural strength did not differ among the five polymerizing units. The present results indicate that the Cesead N and Solidex Hardura composites can be adequately polymerized with laboratory LED units.

The present study aimed to test the antimicrobial activity of Streptococcus dentisani (S. dentisani) supernatant against a collection of microorganisms implicated in dental root infections, and to analyze morphological changes induced in a selection of the tested microorganisms. A total of 22 microbial species were selected, and their growth was monitored by spectrophotometry in the presence and absence of the supernatant of S. dentisani at different assay concentrations (0.2×, 1×, 2×). The generation time and maximum growth rates were evaluated under every tested condition. Scanning electron microscope (SEM) images were obtained to assess the effect on the cell surface following incubation of the pathogens with the concentrated (2×) supernatant of S. dentisani. The supernatant of S. dentisani was found to exert effective inhibitory activity against most of the studied microorganisms implicated in dental root infections (20 out of 22). Total growth inhibition was observed in the case of Streptococcus oralis, Streptococcus sobrinus, Streptococcus salivarius, Prevotella intermedia, and Streptococcus mutans, while the rest of the microorganisms showed an increase in the generation time (between 30 min and 4 h). SEM images revealed structural changes in the membrane consistent with bacteriocin activity, although the effects were heterogeneous among the different species tested.