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This article discusses the development of long-acting local anesthetics for postoperative pain management. The use of opioids for pain relief can lead to adverse effects, so researchers have been exploring alternative options. The article explores different strategies, including quaternary lidocaine derivatives, voltage-gated sodium channel antagonists, site-1 sodium channel blockers, and controlled-release local anesthetics. While some of these options have shown promise, there are still limitations and challenges to overcome before they can be widely used in clinical practice. [Extracted from the article]

The COVID-19 pandemic is ongoing as of September 2022. Since January 2020 when the first case was reported in Japan, the medical community faced a variety of problems both domestically and internationally. It is meaningful to review the impact of COVID-19 from an anesthesiologist's perspective to clarify our policy for future infectious disease outbreaks. In this year's Journal of Anesthesia (JA) symposium, five experts who were deeply involved in the COVID-19 response reviewed the past 2.5 years and made recommendations for potential future pandemics. Anesthesiologists are specialists in airway management and their role in intubating patients with COVID-19 has received much attention. However, they have also played an important backup role in intensive care as critical care physicians and must be more involved in critical care in regular (non-pandemic) times to properly fulfill this role. It is especially important for the Japan Society of Anesthesiologists and JA to quickly disseminate accurate information on unknown infectious diseases to the medical community and wider society. Therefore, it is important to promptly publish papers that are quality-assured through peer review. [ABSTRACT FROM AUTHOR]

Lipid emulsion infusion is a first-line therapy against the toxicity of local anesthetics and is a potential treatment for other drug overdoses, especially for highly lipophilic drugs. Considering the lipophilic property of volatile anesthetics, we hypothesized that lipid emulsion could reverse general anesthesia. Using adult rats, we tested the effect of lipid emulsion infusion on time to emergence after discontinuation of sevoflurane and isoflurane, and further evaluated restoration of righting reflex under continuous sevoflurane anesthesia. Electroencephalogram during lipid emulsion infusion was also investigated under continuous sevoflurane inhalation. The effect of lipid emulsion on sevoflurane-induced respiratory and hemodynamic depressions was evaluated by measuring respiratory rate, PaCO2 (arterial partial pressure of CO2), blood pressure, and heart rate. The binding property of lipid emulsion on sevoflurane and isoflurane was assessed using in vitro setting with a conical flask. Lipid emulsion infusion significantly decreased time to emergence from sevoflurane anesthesia (131 ± 53 vs. 237 ± 69 s) and restored righting reflex during continuous sevoflurane inhalation, by comparing normal saline infusion. Consistent with the behavioral findings, the electroencephalogram under continuous sevoflurane showed decreased power of the δ bands at 5 min after the initiation of lipid emulsion infusion. In addition to reversing hypnosis, lipid emulsion recovered respiratory as well as hemodynamic depressions induced by sevoflurane. Decreased time to emergence was observed also in isoflurane anesthesia (203 ± 111 vs. 314 ± 154 s). To investigate the binding mechanism of lipid emulsion infusion, in vitro experiments revealed significantly decreased anesthetic concentrations of sevoflurane and isoflurane by mixing with lipid emulsion. Lipid emulsion facilitated reversal from volatile anesthetics, as shown by several parameters. As lipid emulsion could bind to volatile anesthetics and simply decrease their effects, our findings suggest that lipid emulsion is a potentially useful agent to reverse general anesthesia. [ABSTRACT FROM AUTHOR]

Purpose: To elucidate the clinical course of patients with coronavirus disease 2019 (COVID-19) treated at a specialized hospital mainly for those with mild and moderate severity during the third wave, and to compare that with the first and second (1st/2nd) waves. Methods: We retrospectively reviewed the severity on admission, treatment, and outcome of a total of 581 patients from September, 2020, to March, 2021, and examined the risk factors for deterioration of respiratory condition, defined as requiring oxygen ≥ 7 L/min for 12 h. Results: The median age was 78 (interquartile range 62−83) years, older than in the 1st/2nd waves (53 years), and 50% of the patients was male. The number of patients classified as mild (peripheral oxygen saturation (SpO2) ≥ 96%), moderate I, II, and severe (requiring admission to the ICU or mechanical ventilation) was 121, 324, 132, and 4, respectively. Favipiravir, ciclesonide, dexamethasone, and/or heparin were administered for treatment. Respiratory condition recovered in 496 (85%) patients. It worsened in 81 patients (14%); 51 (9%) of whom were transferred to tertiary hospitals and 30 (5%) died. Mortality rate increased by fivefold compared during the 1st/2nd waves. Age, male sex, increased body mass index, and C-reactive protein (CRP) on admission were responsible for worsening of the respiratory condition. Conclusion: Patients were older in the third wave compared with the 1st/2nd waves. Respiratory condition recovered in 85%; whereas 5% of the patients died. Old age, male sex, increased body mass index, and CRP would be responsible for worsening of the respiratory condition. [ABSTRACT FROM AUTHOR]

Purpose: To characterize the clinical features and outcome of patients treated at a specialized hospital for coronavirus disease 2019 (COVID-19). Methods: We retrospectively reviewed the symptoms on admission, treatment, and outcome of a total of 300 patients with mild (peripheral oxygen saturation (SpO2) ≥ 96%), moderate I (93% < SpO2 < 96%), moderate II (SpO2 ≤ 93%) and severe (requiring admission to the ICU or mechanical ventilation) COVID-19. Results: Median age was 53 (interquartile range [IQR] 33–72) years and 57% was male. The number of patients with mild, moderate I, II and severe condition was 85, 138, 61 and 16, respectively. Common presenting symptoms were cough (n = 71), loss of taste (42), loss of smell (39), fever ≥ 37.5 °C (36). Dyspnea was observed only 21 cases; 57 reported no symptoms on admission. Favipiravir, ciclesonide, dexamethasone, and heparin were administered in 106, 168, 65, and 38 patients, respectively, but not remdesivir. The median duration of hospitalization was 10 (7–15) days. All patients with mild and moderate I severity were discharged. Among the 77 patients classified as moderate II or severe, 3 were transferred to tertiary hospitals for further treatment on the day of admission. The respiratory condition worsened in 21 patients; 18 required transfer to tertiary hospitals 3 (median) days after admission and 3 died. Conclusion: Respiratory condition recovered in 92%; whereas it worsened in 7% and the mortality rate was 1%. The ratios of male patients, of patients with diabetes mellitus in those with the decreased respiratory condition, were significantly higher than recovered. [ABSTRACT FROM AUTHOR]

Recently published case reports relating to anesthesia in patients with coronavirus disease (COVID-19) were reviewed. The diagnosis of COVID-19 was confirmed by positive results of reverse transcriptase polymerase chain reaction test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Numerous reports handled emergency cesarean delivery. Primary symptoms and laboratory data of pregnant women with COVID-19 were similar to those of non-pregnant patients. Although the mortality rate is reported to be high after surgery in patients with COVID-19, cesarean delivery was successfully performed under regional anesthesia in most cases and postoperative course was favorable both in the parents and newborns. There is no direct evidence of vertical mother-to-child transmission of SARS-CoV-2; however, a diagnosis of COVID-19 was made in a newborn two hours after delivery from a pregnant woman with COVID-19, based on the increased immunoglobulin levels and deranged liver function, suggesting that its possibility cannot be completely eliminated. Emergency cerebral shunt reconstruction was performed repeatedly in an eight-month-old boy with COVID-19. The tracheal tube was removed in the operating room after surgery and postoperative course was uneventful. All the procedures should be performed in isolated operating rooms with medical staff with level-3 personal protection to ensure the safety of patients and health care providers. [ABSTRACT FROM AUTHOR]

Purpose: To compare effects of free-hand and mechanically applied uniform irradiation on tensile bond strength of 4- META/MMA-TBB resin to Er:YAG laser-irradiated dentin using an X-Y moving stage. Materials and Methods: Three different laser conditions were evaluated: 1.0 W, 100 mJ/pulse, 10 pps; 1.0 W, 50 mJ/pulse, 20 pps; 1.0 W, 33 mJ/pulse, 30 pps. Samples of bovine dentin were set on a moving stage and mechanically irradiated with an Er:YAG laser at a scanning speed of 1.0 mm/s or subjected to free-hand irradiation. The lased dentin surfaces were acid conditioned with 10% citric acid/3% ferric chloride for 15 s, rinsed, and dried. The surfaces were bonded to PMMA rods with 4-META/MMA-TBB resin, and mini-dumbbell-shaped bonded specimens were prepared. Tensile bond strength was measured and compared with the results for free-hand irradiated samples obtained under the same conditions in an earlier study. SEM observations of fractured surfaces after tensile bond testing were also performed. Results: A significant difference was found in tensile bond strength among the 3 laser settings in both free-hand and mechanically uniform irradiations. A comparison of free-hand laser irradiation and mechanically performed uniform laser irradiation revealed no significant difference under either laser condition (p > 0.05). SEM observation of the fractured surfaces showed no difference between the two irradiation methods under all laser conditions. Conclusion: No significant difference was found in tensile bond strength between free-hand and mechanically irradiated dentin. Significant differences were found, however, with changes in laser setting in both groups. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to measure the flexural strength and the elastic modulus of composite resin with and without reinforcing fibers and to evaluate the reinforcing effect of various fibers. Materials and Methods: A polyethylene fiber (Ribbond), a polyaramid fiber (Fibreflex), and three glass fibers (FibreKor, GlasSpan, Vectris) were used to reinforce composite resins. The flexural strength and elastic modulus of specimens in the three-point bending mode were measured using a universal testing machine at a cross-head speed of 1 mm/min after storage in water at 37°C for 24 hours. All tests were carried out in a water bath at 37°C. The data were analyzed using analysis of variance and the Sheffé test at P = 0.05. After testing, the fractured surface was evaluated using a scanning electron microscope at 50, 500, and 3,000 magnifications. Results: Yield flexural strengths of nonreinforced resins were 48 to 56 MPa, and those of reinforced resins were 56 to 134 MPa. Ultimate flexural strengths of nonreinforced specimens were 96 to 119 MPa, and those of reinforced ones were 203 to 386 MPa. Elastic modulus of nonreinforced resin was 6 to 9 GPa, and fiber reinforcing increased the value to 9 to 15 GPa, while it had no effect in Ribbond. Conclusion: Most of the fibers used in this study increased both yield and ultimate flexural strengths of composite resins, with the exception of the yield strength of Vectris. GlasSpan, Fibreflex, and FibreKor were effective in reinforcing elastic modulus, while Ribbond had no effect on it. Unidirectional glass fibers and polyaramid fiber were effective in reinforcing both flexural strength and elastic modulus of composite resin. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluated the effect of acid conditioners on resin bonding to dentin following irradiation with an Er:YAG laser and investigated the characteristics of resin bonding to the laser-treated dentin. Materials and Methods: Extracted bovine teeth were cervically sectioned to expose a dentin surface. After polishing, the dentin was irradiated with an Er:YAG laser. Aqueous solutions of 10% citric acid (10-0) or 10% citric acid/3% ferric chloride (10-3) were then applied to the laser-treated surface as acid conditioners. After the acid treatment, a PMMA rod was bonded to the irradiated dentin using 4-META/MMA-TBB resin, and miniaturized dumbbell-shaped bonded specimens were prepared. These specimens were subjected to tensile testing, and fractured surfaces were observed with field-emission scanning electron microscopy (FE-SEM) to determine the mode of fracture. Additionally, the resin-dentin interfaces were observed under FE-SEM. Results: The tensile bond strength of acid-conditioned bonded specimens was lower than that of specimens not subjected to acid treatment (11.1 MPa) in the laser-irradiated group. No significant difference was observed between 10-0 and 10-3 treatments. 10-3 treatment yielded the highest bond strength (24.6 MPa) in the nonirradiated group, as opposed to only 7.7 MPa in the laser-treated group. Cohesive failure in the dentin was observed in almost all specimens in the irradiated group. Furthermore, a 10- to 30-µm-thick resin-penetrated layer was observed at the interface between the dentin and the resin. Conclusion: These results suggest that the effect of acid conditioners on resin bonding to dentin differs according to whether the dentin has been laser irradiated or not. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effects of fatigue on the strength of materials used in all-ceramic crowns, the biaxial flexural strength of air-ceramic restorative materials was measured with precracked and laminated specimens after cyclic loading. Materials and Methods: Two types of all-ceramic systems were used to prepare specimens: a glass-infiltrated alumina core system (In-Ceram) and a leucite-reinforced feldspathic porcelain system IPS-Empress). Monolayer and laminated disks with a diameter of about 11.75 mm and a thickness of 1.20 ± 0.05 mm were prepared. The biaxial flexural strength of the specimens that were polished and/or created with a precrack was measured. Their strength was also measured following cyclic loading. A cyclic load that was 60% of the mean breaking load of the specimens (before cyclic loading) was applied to specimens for 105 cycles in 37°C water. Results: Although 20% to 30% of the polished specimen samples fractured during cyclic loading, the biaxial flexural strength of specimens that survived the cyclic loading was nearly the same as that of specimens not subjected to the cyclic loading. The strength of the alumina system decreased with the introduction of precracks, and nearly all specimens fractured during cyclic loading. The strength of the leucite system, however, did not decrease with the presence of precracks, and no fractures were observed on these specimens during cyclic loading. Conclusion: These results suggest that although the alumina system has high flexural strength, it is more sensitive to flaws and susceptible to fatigue fracture. The effect of fatigue on the leucite system appears to be low. [ABSTRACT FROM AUTHOR]

Keywords: Pharmacodynamics; Pharmacokinetics; Reparalysis; Rocuronium; Sugammadex EN Pharmacodynamics Pharmacokinetics Reparalysis Rocuronium Sugammadex 803 805 3 11/20/20 20201201 NES 201201 Sugammadex is extensively used since its introduction to our country in 2010; however, there is a paucity of data showing its optimal dose for reversal of neuromuscular blockade, particularly shortly after administration of muscle relaxants. Dose of sugammadex for neuromuscular blockade According to the previous studies, sugammadex 2 mg/kg was derived as adequate dose for reversal of moderate neuromuscular blockade by rocuronium and vecuronium. Dose of rocuronium for reparalysis after administration of sugammadex The model by Kashima et al. [[3]] also explained the required dose of rocuronium to provide neuromuscular blockade after reversal by sugammadex. Reversal of profound, high-dose rocuronium-induced neuromuscular blockade by sugammadex at two different time points: an international, multicenter, randomized, dose-finding, safety assessor-blinded, phase II trial. [Extracted from the article]

Background: Ovarian vein thrombosis is a rare complication of pregnancy. The representative complaints of patients with ovarian vein thrombosis are abdominal pain and fever. In some cases, however, fatal pulmonary embolism may develop. We report a case of pulmonary embolism presenting with severe hypotension and loss of consciousness during cesarean section possibly caused by ovarian vein thrombosis. Case presentation: A 25-year-old woman at 38 weeks 4 days of gestation was scheduled for repeat cesarean section. Her past history was unremarkable, and the progress of her pregnancy was uneventful. She did not experience any symptoms indicative of deep vein thrombosis. Cesarean section was performed under spinal anesthesia, and a healthy newborn was delivered. After removal of the placenta, she suddenly developed dyspnea, hypotension, and loss of consciousness with decreased peripheral oxygen saturation. Blood pressure, heart rate, and oxygen saturation recovered after tracheal intubation and mechanical ventilation with oxygen. Postoperative computed tomography revealed no abnormality in the brain or in the pulmonary artery, but a dilated right ovarian vein with thrombi, extending up to the inferior vena cava, was found. A diagnosis of pulmonary embolism caused by ovarian vein thrombosis was made, and heparin was administered. The tracheal tube was removed on the first postoperative day. Her postoperative course was uneventful, and she was discharged with no complications. Conclusion: Fatal pulmonary embolism might be caused by ovarian vein thrombosis during cesarean section. Careful and continuous observation of the patient after delivery and prompt treatment are important. [ABSTRACT FROM AUTHOR]

Purpose: We examined the hypothesis that 1 minimum alveolar concentration (MAC) of desflurane and sevoflurane provides different depth of anesthesia. Methods: One hundred and twenty young (20-30 years), middle-aged (31-65 years), and elderly (66-80 years) patients were randomly allocated to receive either desflurane or sevoflurane ( n = 20, each group). General anesthesia was induced with propofol 2 mg/kg bolus and remifentanil 0.25 µg/kg/min, which was stopped after tracheal intubation. Maintenance of anesthesia was started with an end-tidal concentration of desflurane or sevoflurane at age-adjusted 1 MAC and maintained for 10 min, followed by 1-min assessment of bispectral index (BIS), 95% spectral edge frequency (SEF95), and amplitude of the electroencephalogram taken at 10-s intervals. Results: BIS and SEF95 in patients receiving 1 MAC desflurane were significantly lower than those receiving 1 MAC sevoflurane including all age groups [35 (29, 39) vs. 41 (38, 49); 12.53 (10.99, 13.95) Hz vs. 14.42 (12.99, 17.17) Hz median (25, 75 percentile), respectively, P < 0.001 for both]. Both BIS and SEF95 in young patients were lower than in middle-aged and elderly patients receiving either desflurane or sevoflurane ( P < 0.001 for both). There were no differences in amplitude between patients receiving desflurane and sevoflurane. Conclusions: BIS as well as SEF95 were lower in patients receiving 1 MAC desflurane than those receiving 1 MAC sevoflurane, suggesting that desflurane provides higher depth of anesthesia than sevoflurane at 1 MAC. [ABSTRACT FROM AUTHOR]

Background Electrocorticogram (ECoG) spike activity is enhanced under general anesthesia with 1.5 minimum alveolar concentration (MAC) sevoflurane compared with lower concentrations in adult patients with epilepsy. However, the effect of concentration of sevoflurane on ECoG in children with epilepsy is less known. Aims The primary endpoint was to investigate the effects of sevoflurane on ECoG spike activity in pediatric patients undergoing epilepsy surgery. The secondary endpoint was to examine its effects on baseline ECoG including burst suppression. Methods Children of age 3-18 years with medically intractable epilepsy undergoing corpus callosotomy or resection of the epileptic foci ( n = 11) were enrolled. Electrodes were placed on the brain surface and ECoG was recorded under anesthesia with endtidal carbon dioxide tension at 30 mmHg and sevoflurane at 2.5%, followed by age-adjusted 1.5 MAC (3.1-3.4%) for 10 min. The number of leads with spikes, the average number of spikes per lead per minute, median frequency of ECoG, and duration of suppression of ECoG ≥ 1 s were compared between 2.5% and 1.5 MAC sevoflurane. Results The number of leads with spikes increased [11 vs 14, P = 0.003, difference in mean (95% CI) is 3 (2-5)], and the average number of spikes increased [9 vs 14·lead−1·min−1, P = 0.003, difference in mean (95% CI) is 5 (2-8) lead−1·min−1] under anesthesia with 1.5 MAC compared with 2.5% sevoflurane. Median frequency was decreased [2.8 Hz vs 2.0 Hz, P = 0.003, difference in mean (95% CI) is 0.8 (0.4-1.2) Hz], and the duration of suppression was increased [105 s vs 262 s, P < 0.001, difference in mean (95% CI) is 156 (90-223) s] with 1.5 MAC compared with 2.5% sevoflurane. Conclusions Sevoflurane at 1.5 MAC significantly increased the extent and the number of spikes, prolonged the duration of suppression, and decreased median frequency of ECoG compared with those at 2.5% sevoflurane. [ABSTRACT FROM AUTHOR]

Numerous studies have implicated the involvement of nonscavenging effect of lipid emulsion for local anesthetic systemic toxicity from the initial stage of research. Partownavid et al. [[11]] demonstrated that free fatty acid oxidation is essential for successful recovery of bupivacaine-induced cardiotoxicity by lipid emulsion in vivo and in mitochondrial suspension. Besides using less-toxic anesthetics such as ropivacaine and levobupivacaine, various techniques, e.g., liposomal bupivacaine and transdermal lidocaine delivery system, have been performed to prolong the effect of local anesthetics and to minimize the required dose [[18]]. [Extracted from the article]

This study evaluated the microtensile bond strength (μTBS) of 1-step self-etch adhesives (1-SEAs) and 2-step self-etch adhesives (2-SEAs) to pulp chamber dentin immediately after bleaching with 2 types of common bleaching techniques. Pulp chamber dentin of bovine teeth was bleached using 30% hydrogen peroxide (H2O2) solution with quartz-tungsten-halogen light-curing unit (Group 1) and 3.5% H2O2-containing titanium dioxide (TiO2) (Pyrenees®) activated with 405-nm violet diode laser for 15 min (Group 2). Unbleached specimens were placed in distilled water for 15 min and used as controls. After treatment, dentin was bonded with resin composite using 1-SEA or 2-SEA and stored in water at 37°C for 24 h. Each specimen was sectioned and trimmed to an hourglass-shape and μTBS was measured. Fractured specimens were examined under a scanning electron microscope to determine fracture modes. All specimens in Group 1 failed before proper bonding tests. In Group 2, the μTBS of 2-SEA was significantly greater (with no failed specimens) than 1-SEA (where 21 out of 36 failed). These results indicate that 2-SEA is a better adhesive system than 1-SEA on bleached dentin. Our results also demonstrated that application of H2O2 significantly decreases bond strength of resin to dentin; however, in the case of nonvital tooth bleaching, Pyrenees® is a better alternative to the conventional 30% H2O2 bleaching. [ABSTRACT FROM AUTHOR]

The author comments on the impact of the use of long-acting local anesthetics for both neuraxial and peripheral nerve block in children. Long-acting local anesthetics such as bupivacaine, levobupivacaine and ropivacaine have higher toxic potency than lidocaine. Research on toxicity and pharmacokinetics in children would help avoid adverse effects and improve the quality of anesthesia practice.

PHACE syndrome is a neurocutaneous syndrome characterized by the association of large cutaneous hemangiomas and the cardiac and cerebral vascular anomalies. We report a 6-year-old female with PHACE syndrome presented with left facial hemangiomas, cystic lesion in the cerebral posterior fossa, coarctation of the aorta, aplasia of the left vertebral artery and stenosis of the left internal carotid artery. Surgical repair of the aorta with left heart bypass under beating heart was scheduled. We monitored regional cerebral oxygen saturation (rSO) with infrared spectroscopy in order to detect cerebral hypoperfusion. A decrease of rSO ipsilateral to the cerebrovascular anomalies occurred during anastomosis of the aorta, which was treated by reducing the flow rate of left heart bypass and by increasing the inhalational oxygen concentration. As children with PHACE syndrome are frequently accompanied with cerebrovascular anomalies and at a risk of cerebral hypoperfusion, prevention of cerebral hypoperfusion is crucially important during general anesthesia. [ABSTRACT FROM AUTHOR]

The article discusses the use of intravenous lipid emulsion in the treatment of toxicity caused by lipophilic agents. It is hypothesized that partitioning and enhanced metabolism are possible mechanisms of the antidote effect of lipid emulsion, which is supported by studies on both animal and human subjects. The American Heart Association Advanced Cardiac Life Support (ACLS) released a protocol recommending the use of adrenaline in resuscitating patients for local anesthetic overdose.

The purpose of this study was to compare the retention of fiber-reinforced composite (FRC) posts luted with either conventional or self-adhesive resin cement. The FRC posts and core resin were built up in bovine teeth. The posts were luted with standard etch-and- rinse cement, self-etch cement, or one of two self-adhesive cements. The samples were stored in water for 1 or 14 days or subjected to thermal cycling (TC). Retention value was measured with the pull-out test using a universal testing machine. Conventional adhesive resin cement yielded significantly greater retention than self-adhesive resin cement at 1 day. No significant difference was observed in retention among the adhesive systems tested at 14 days or after TC. During the early luting stage, self-adhesive resin cement yielded lower retention value than conventional resin cement. After 14 days storage or TC, retention was comparable to that with conventional resin cement. [ABSTRACT FROM AUTHOR]

Purpose: Despite numerous studies examining the effect of lipid emulsion on bupivacaine-induced cardiac toxicity, few studies have examined its effect on central nervous system (CNS) toxicity of local anesthetics. We investigated the effect of lipid emulsion on the CNS and cardiac toxicity of bupivacaine and levobupivacaine in awake, spontaneously breathing rats. Methods: Male Sprague-Dawley rats were randomly allocated to control-bupivacaine (CB), control-levobupivacaine (CL), lipid-bupivacaine (LB), and lipid-levobupivacaine (LL) groups ( n = 8 in each group). After infusion of saline (CB and CL groups) or 20 % lipid emulsion (LB and LL groups) for 5 min, bupivacaine (CB and LB groups) or levobupivacaine (CL and LL groups) was administered IV at 1 mg/kg/min. Cumulative dose of anesthetics and their plasma concentrations at the onset of convulsions and cardiac arrest were measured. Results: The doses of bupivacaine for inducing convulsions and cardiac arrest in the LB group (8.8 ± 1.7 and 10.2 ± 1.5 mg/kg, respectively) were significantly larger than those in the CB group (5.9 ± 1.1 and 7.1 ± 1.3 mg/kg, respectively, p < 0.001 for both). The doses of levobupivacaine for inducing convulsions and cardiac arrest in the LL group (10.0 ± 2.0 and 13.7 ± 3.6 mg/kg, respectively) were significantly larger than those in the CL group (7.7 ± 1.6 and 9.4 ± 2.4 mg/kg, p = 0.03 and p = 0.02, respectively). Plasma concentrations of bupivacaine at the onset of convulsions and cardiac arrest in the LB group (12.9 ± 2.9 and 41.4 ± 5.2 μg/ml, respectively) were significantly higher than those in the CB group (7.9 ± 1.2 and 21.6 ± 3.3 μg/ml, respectively, p < 0.001 for both). Plasma concentrations of levobupivacaine at the onset of convulsions and cardiac arrest in the LL group (17.5 ± 1.5 and 47.6 ± 6.1 μg/ml, respectively) were significantly higher than in the CL group (10.9 ± 2.2 and 29.2 ± 3.5 μg/ml, respectively, p < 0.001 for both). Conclusions: Lipid emulsion decreased CNS and cardiac toxicity of both bupivacaine and levobupivacaine. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of reinforcing polyaromatic polyamide (aramid) fibers with various orientations on the flexural properties of denture base resin. Aramid fibers with four orientations of unidirectional, woven, non-woven and paper-type were pre-impregnated and placed at the bottom of a specimen mold. Heat-polymerized denture base resin was packed over the fibers and polymerized. A three-point bending test was performed using a universal testing machine at a crosshead speed of 5 mm/min. The flexural strengths and fiexural moduli of the unidirectional and woven groups were significantly higher than those of the control and other experimental groups. For the fiexural moduli, all experimental groups showed significantly higher reinforcing effects than the control group. In conclusion, the unidirectional group located perpendicular to the direction of the load was most effective in reinforcing the denture base resin, followed by the woven group. [ABSTRACT FROM AUTHOR]

Purpose: We compared the insertion performance of the pediatric size 1.5-3 i-gel airway device with that of the ProSeal laryngeal mask airway (PLMA) in anesthetized children in a prospective, randomized, controlled manner. Methods: We included 134 children, aged 3 months to 15 years, scheduled for elective surgery under general anesthesia. They were randomly divided into the i-gel and the PLMA groups according to the airway device used. The primary outcome variable was oropharyngeal leak pressure. Other outcome variables were ease of insertion, required time for insertion, fiberoptic view, and first-attempt and overall success rates. Results: There were no differences in the ease of insertion, insertion time, or leak pressure between the devices. Fiberoptic view was significantly better with the i-gel than with the PLMA ( P = 0.002). The view was significantly better with the sizes 2, 2.5, and 3 i-gel than with the size 1.5 i-gel ( P = 0.02, 0.004 and 0.002, respectively), and the view was significantly better with the sizes 2.5 and 3 PLMA than with the size 1.5 PLMA ( P = 0.02 and 0.005, respectively). The first-attempt success rates were 94 and 97 % in the i-gel and the PLMA groups, respectively; the success rates including the second attempt were 100 % in both groups. No children developed side effects requiring treatment with either device. Conclusion: Both the pediatric i-gel and the PLMA were successfully inserted in children. The fiberoptic view was better with the i-gel than with the PLMA. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate change in color in experimental titanium-20mass% chromium (Ti-20Cr) alloy in an oral environment. Pure Ti and Ti-6Al-7Nb and Co-29Cr-5Mo alloys, as references to compare change in color, were prepared by casting. The cast specimen was mirror-polished. Each specimen was affixed to a palatal plate and the plate then worn by a volunteer for up to 300 h. A few specimens showed a change in color. These changes and the median values among the tested alloys were not significant. Larger amounts of carbon, nitrogen, and oxygen were observed in the discolored alloys than in the slightly-discolored alloys. The spectra of the constituent elements of the alloys revealed no corrosion. In conclusion, the experimental Ti-20Cr alloys showed a level of resistance to change in color and corrosion similar to that in commercially available Ti and Co-29Cr-5Mo alloys. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the reinforcing effects of three types of fibers at various concentrations and in different combinations on flexural properties of denture base resin. Glass (GL), polyaromatic polyamide (PA) and ultra-high molecular weight polyethylene (PE) fibers were added to heat-polymerized denture base resin with volume concentrations of 2.6%, 5.3%, and 7.9%, respectively. In addition, hybrid fiber-reinforced composite (FRC) combined with either two or three types of fibers were fabricated. The flexural strength, modulus and toughness of each group were measured with a universal testing machine at a crosshead speed of 5 mm/min. In the single fiber-reinforced composite groups, the 5.3% GL and 7.9% GL had the highest flexural strength and modulus; 5.3% PE was had the highest toughness. Hybrid FRC such as GL/PE, which showed the highest toughness and the flexural strength, was considered to be useful in preventing denture fractures clinically. [ABSTRACT FROM AUTHOR]

Pena-Shokeir syndrome is a rare, early lethal disease. It is characterized by fetal growth restriction; craniofacial deformities, for example micrognathia and microcephaly; multiple ankyloses; and pulmonary hypoplasia. For patients with this syndrome, maintenance of airway and control of perioperative respiratory complications are important for anesthetic management. We report 3 pediatric cases of Pena-Shokeir syndrome undergoing tracheostomy and arthrolysis under general anesthesia using sevoflurane, nitrous oxide, fentanyl, and vecuronium bromide. Anesthetic procedures including mask ventilation, tracheal intubation, and extubation were successfully performed without complications during and after surgery. In patients with Pena-Shokeir syndrome, inhalational anesthetics can be safely used for induction and maintenance of anesthesia, although it is important to assume that difficult airway management might be encountered. [ABSTRACT FROM AUTHOR]

Primary tracheal tumors are rare in adults, and careful airway management is required during anesthesia for affected patients. We report the case of a patient with tracheal hemangiomas undergoing nontracheal operation. A 61-year-old woman was scheduled for a lung operation. During preoperative examination, hemangiomas were detected on the tracheal mucosa. As she was asymptomatic and the degree of airway stenosis was small, treatment was not required for the hemangiomas, and left upper lobectomy for lung cancer was scheduled. After induction of general anesthesia, a regular tracheal tube was inserted under fiberoptic bronchoscopy, with care taken to prevent damage to the hemangiomas. An endobronchial blocker was inserted for one-lung ventilation. The operation was performed uneventfully, and the tracheal tube was replaced postoperatively with a laryngeal mask airway while the patient was under deep anesthesia and neuromuscular blockade. The mask was removed after confirming lack of bleeding from the hemangiomas. No hypoxia or other complications occurred during or after the operation. [ABSTRACT FROM AUTHOR]

24-year-old man underwent surgery for a fractured left clavicle and received an interscalene brachial plexus block for intraoperative and postoperative analgesia. After injection of 40 ml 0.5% ropivacaine and confirmation of analgesia, general anesthesia was induced and maintained with propofol. Although the operation was completed uneventfully, the patient was restless and there was limb twitching during emergence from anesthesia. Ropivacaine-induced toxicity was suspected, and a dose of 100 ml 20% lipid emulsion was infused intravenously. The symptoms of toxicity disappeared, and there was full recovery of consciousness within 5 min. Plasma concentrations of total and protein-unbound ropivacaine measured 2 h 20 min after local injection were 1.99 and 0.13 μg/ml, respectively. After infusion of lipid emulsion, the ropivacaine concentrations decreased to 1.72 and 0.05 μg/ml, respectively. The patient had no pain, and neurological examination revealed sensory loss around the clavicle. The patient was discharged without any complications. [ABSTRACT FROM AUTHOR]

The aim of this study was to estimate the flexural properties of three kinds of experimental fiber-reinforced composite (FRC) posts and to evaluate their potential use as posts. Experimental FRC posts were fabricated with glass, aramid, and UHMWP fibers. Commercial FRC posts were used for comparison. A three-point bending test was performed at a crosshead speed of 1 mm/min. Experimental glass fiber posts showed significantly higher flexural strengths and moduli than aramid and UHMWP posts. Experimental UHMWP posts demonstrated superior toughness to the commercial posts. The glass fiber posts displayed stiff, strong and brittle features, while the UHMWP posts were flexible, weak and ductile. The flexural properties of the aramid posts fell between those of the glass and UHMWP posts. In conclusion, the glass fiber posts proved excellent in flexural strengths and moduli. However, the superior toughness of UHMWP fibers suggests the possibility of their use as posts in combination with glass fibers. [ABSTRACT FROM AUTHOR]

The mechanical properties of a series of binary Ti-Cr alloys were investigated. Chromium content ranged from 5 to 20 mass%. Dumbbell- and disk-shaped specimens of each alloy were obtained by casting for mechanical testing and microstructural observation. Yield strength (YS) at 0.2%, tensile strength (TS), elongation (EL) and Vickers hardness (Hv) were determined. The TS and YS of Ti-l5Cr were similar to those of Ti-20Cr at approximately 880 or 900 MPa and higher than those of cp-Ti by nearly 55%. Among all Ti-Cr alloys, Ti-l0Cr showed the lowest EL. At 50 μm below the surface, Hv ranged from 370 to 420. Addition of 15 or 20 mass% chromium to titanium yielded sufficient strength and relatively high elongation values. Judging from the results of the mechanical properties, the suitability of Ti-Cr alloys with 15 or 20 mass% chromium for use in dental prostheses. [ABSTRACT FROM AUTHOR]

To examine the relationships between effect-site concentrations and electroencephalographic parameters after the induction of general anesthesia with midazolam. Twenty-four patients with American Society of Anesthesiologists status I or II were randomly allocated to receive either an intravenous (i.v.) bolus of midazolam 0.2 mg kg−1 (small-dose group, n = 12) or 0.3 mg kg−1 (large-dose group, n = 12) for induction of general anesthesia in a double-blind experimental design. The bispectral index (BIS), 95% spectral edge frequency (SEF95), spectral power density, and plasma concentrations of midazolam were measured for 60 min following the induction of general anesthesia. Plasma and simulated effect-site concentrations of midazolam were significantly higher in the large-dose group than in the small-dose group ( P = 0.005 and <0.001, respectively). There was a correlation between the relative beta ratio and BIS ( r2 = 0.30, P < 0.001; n = 168); however, effect-site concentrations of midazolam showed no association with BIS, relative beta ratio, or SEF95 ( r2 = 0.07, 0.11 and 0.01, respectively; n = 168). The electroencephalographic spectral power density in the beta-band (≥13 and <30 Hz) was significantly increased after induction and was significantly larger in the large-dose group than in the small-dose group ( P = 0.009). Following the induction of general anesthesia with i.v. midazolam 0.2 or 0.3 mg kg−1, the BIS was positively correlated with the relative beta ratio. Despite a rapid decrease in the plasma and effect-site concentrations of midazolam, the average BIS remained >60 for 60 min after induction, reflecting an increased power of the electroencephalographic high-frequency band. [ABSTRACT FROM AUTHOR]

We examined the hypothesis that remifentanil decreases the bispectral index (BIS) as well as blunts cardiovascular responses to tracheal intubation during anesthesia with midazolam. Sixty patients were randomly allocated to three groups according to the dose of remifentanil—0.1 (S), 0.2 (M), or 0.5 (L) μg kg−1 min−1, respectively. Infusion of remifentanil was started 5 min before the induction of general anesthesia with midazolam 0.2 mg/kg in all groups. Following the administration of vecuronium 0.1 mg/kg, the trachea was intubated 5 min after induction, and the infusion rate of remifentanil was then reduced to 0.05 μg kg−1 min−1 in all groups. Mean arterial blood pressure (MAP), heart rate (HR), BIS, and 95% spectral edge frequency (SEF95) were measured until 10 min after tracheal intubation. Infusion of remifentanil alone before the induction of anesthesia did not affect the hemodynamic or electroencephalographic parameters. MAP was significantly decreased after induction in all groups of patients ( P < 0.01), with no differences among the three groups, while it was significantly increased after tracheal intubation in the patients of groups S and M, but not in those of group L. The HR did not change after induction in any of the groups, but it was also significantly increased after tracheal intubation of group S and M patients, although not in those of group L. The BIS decreased after induction, and both the BIS and SEF95 were significantly lower in group L patients than in those of group S ( P < 0.01). All patients were unconscious after induction, and none complained of intraoperative awareness. In our patient cohort, remifentanil 0.5 μg kg−1 min−1 effectively decreased the BIS after the induction of general anesthesia with midazolam 0.2 mg/kg and suppressed the increase of MAP and HR in response to subsequent laryngoscopy and tracheal intubation. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the durability of unidirectional and bidirectional fiber-reinforced post systems under static and cyclic loading. Three prefabricated fiber posts with one of two core composite resins each or a post resin were used. Each specimen was subjected to a three-point bending test after cyclic loading (1000 times) by 0.1, 0.2 or 0.3 mm deflection. Under cyclic loading, flexure strength and elastic modulus tended to show a decrease with increase in deflection in the unidirectional fiber post specimens. No such tendency, however, was observed in the bidirectional fiber post specimen. In conclusion, use of a prefabricated fiber post in a post-and-core complex improved the flexural properties of the core composite resin, regardless of fiber direction. Although deterioration in flexural properties was observed with cyclic loading in the unidirectional fiber post specimens, no significant difference was observed in the bidirectional fiber post specimen. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine whether the brushing durability of a titanium dioxide coating on a polymethyl methacrylate (PMMA) substrate was improved by prior treatment with an acryloxypropyl trimethoxysilane-based agent. Titanium dioxide coatings were obtained by spray-coating substrates with or without prior treatment. Structure was investigated using IR, SEM, and an EPMA. Effect on durability against brushing was determined with a brush-wear test machine utilizing a commercial denture brush. A thin layer comprised of siloxane and TiO2 was formed on a PMMA substrate by prior treatment with an acryloxypropyl trimethoxysilane-based agent and spray-coating of TiO2. Prior treatment demonstrated improved stability against brushing, whereas the titanium coating was removed after less than 1x105 brushing cycles without prior treatment. This suggests that prior treatment with an acryloxypropyl trimethoxysilane-based agent would confer improved durability against brushing-induced stress on a TiO2 coating in its application to dentures. [ABSTRACT FROM AUTHOR]

This study examined the mechanical properties of roots combined with prefabricated fiber post. Three types of specimens were evaluated: (1) prefabricated fiber post alone (FP); (2) core composite resin with FP (CFP); and (3) root with CFP (RCFP). The volume fractions of the prefabricated fiber post in the core composite resin (FP/CFP ratio) were set to 0, 0.16, 0.22, 0.28, and 0.48. Bending test for FP and CFP, and diametral compression test for FP, CFP, and RCFP were carried out. The FP/CFP ratio showed no effect on the diametral tensile strength (DTS) of RCFP; and there were no significant differences in DTS with/without FP. The flexural strength of CFP increased with increase in FP/CFP ratio. The DTS of CFP declined in comparison with that of core composite resin only. [ABSTRACT FROM AUTHOR]

We investigated cell response, including cell proliferation and expression of heat stress protein and bcl-2, to clarify the influence of low-level [gallium-aluminum-arsenide (Ga-Al-As) diode] laser irradiation on Par-C10 cells derived from the acinar cells of rat parotid glands. Furthermore, we also investigated amylase release and cell death from irradiation in acinar cells from rat parotid glands. The number of Par-C10 cells in the laser-irradiated groups was higher than that in the non-irradiated group at days 5 and 7, and the difference was statistically significant (P < 0.01). Greater expression of heat shock protein (HSP)25 and bcl-2 was seen on days 1 and 3 in the irradiated group. Assay of the released amylase showed no significant difference statistically between the irradiated group and the non-irradiated group. Trypan blue exclusion assay revealed that there was no difference in the ratio of dead to live cells between the irradiated and the non-irradiated groups. These results suggest that low-level laser irradiation promotes cell proliferation and expression of anti-apoptosis proteins in Par-C10 cells, but it does not significantly affect amylase secretion and does not induce rapid cell death in isolated acinar cells from rat parotid glands. [ABSTRACT FROM AUTHOR]

Although fluoride induces corrosion in titanium in an oral environment, the influence of protein on this corrosion remains to be clarified. The objective of this study was to investigate suppression of fluoride‐induced corrosion of titanium where albumin was either present in a solution or where albumin was preadsorbed on titanium. Titanium dissolution in titanium specimens and surface characterization of each specimen were determined. Dissolution in a saline solution containing both albumin and fluoride was less than that in only fluoride‐containing saline solution. The titanium specimen was covered in an albumin film. The morphology of the titanium in the fluoride‐containing saline solution revealed jagged edges, whereas titanium immersed in the saline solution containing albumin and fluoride showed a round and plate‐like morphology. When albumin‐adsorbed titanium was immersed in a fluoride‐containing solution, dissolution within 6 h was less than that in non albumin‐adsorbed titanium. Dissolution increased with desorption of adsorbed‐albumin from the titanium surface. The results suggest that albumin in a solution suppresses dissolution of titanium compounds, thus influencing their morphology. Albumin adsorbed on titanium reduces fluoride attack and suppresses dissolution. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [ABSTRACT FROM AUTHOR]

This study compared differences in discoloration and dissolution in several titanium alloys with immersion in peroxide- or fluoride-containing solution. Commercially pure titanium (CP-Ti) and six titanium-based alloys were used: Ti-0.15Pd, Ti-6Al-4V, Ti-7Nb-6Al, Ti-55Ni, Ti-10Cu, and Ti-20Cr. Two test solutions were prepared for immersion of polished titanium and titanium alloys: one consisting of 0.2% NaF + 0.9% NaCl (pH 3.8 with lactic acid) and the other of 0.1 mol/l H2O2 + 0.9% NaCl (pH 5.5). Following immersion, color changes were determined with a color meter and released elements were measured using ICP-OES. Discoloration and dissolution rates differed between the two solutions. In the hydrogen peroxide-containing solution, color difference was higher in Ti-55Ni and Ti-6Al-4V than in any of the other alloys, and that Ti-55Ni showed the highest degree of dissolution. In the acidulated fluoride-containing solution, CP-Ti, Ti-0.15Pd, Ti-6Al-4V, Ti-7Nb-6Al, and Ti-10Cu alloys showed remarkable discoloration and dissolution with immersion. On the contrary, Ti-20Cr alloy showed very little discoloration and dissolution in either solution. [ABSTRACT FROM AUTHOR]

Low hepatic cytochrome P4503A (CYP3A) activities might play an important role for inducing osteonecrosis of the femoral head (ONFH) by corticosteroids. However, the relationship between hepatic CYP3A activity and steroid-induced ONFH is unknown. We have examined the relationship between hepatic CYP3A activity and the inducibility of ONFH in a rabbit model. Sixty rabbits were divided into three groups. Hepatic CYP3A inducer (phenobarbital, group P; n = 15), inhibitor (itraconazole, group I; n = 15), or saline (group C, n = 30) was administrated for 3 weeks before intramuscular methylprednisolone. In groups P and I, hepatic CYP3A levels were measured by midazolam clearance before treatment (baseline) and before methylprednisolone injection. All animals were sacrificed 3 weeks after methylprednisolone injection and both femurs were harvested and examined histologically for osteonecrosis. Midazolam clearance was significantly increased and decreased, compared with baseline in groups P and I respectively ( p < 0.0005, p < 0.002). The incidence of osteonecrosis in group P (33%) was significantly lower than in group I (100%) and group C (83%; p < 0.001 for both). The percentage necrotic area to whole bone marrow area on cross sections in group P (8.2 ± 5.9%) was significantly lower than in group I (69.8 ± 20.8%) and group C (51.5 ± 30.7%; p < 0.005 for both). Hepatic CYP3A activity inversely correlated with the incidence of osteonecrosis and extent of the necrotic area caused by the same dose of corticosteroids, suggesting possible prevention of the steroid-induced osteonecrosis by reducing steroid dose in poor corticosteroid metabolizers. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:91-95, 2008 [ABSTRACT FROM AUTHOR]

Simvastatin acid (SVA) has been reported to stimulate bone formation by increasing expression of BMP-2 in osteoblasts. Due to their multi-functional characteristics and bioadaptability, cyclodextrins (CDs) are capable of forming inclusion complexes with many drugs by including a whole drug molecule inside their cavity. In the present study, we prepared SVA/CD inclusion complex solutions with different pH values. These were then used to determine their SVA release behavior after coating on titanium substrates, as well as to clarify the characteristics of SVA/CD complexes per se. Results showed that the lower the pH value of the solution, the lower the release kinetics of SVA. Besides, the amount of crystalline complexes in the coatings increased with decrease in pH. These results suggested that the release rate of SVA depended on two factors: pH of the solution and concomitant crystallinity of the coating. [ABSTRACT FROM AUTHOR]

Surface wettability is an important physicochemical property of biomaterials, and it would be more helpful for understanding this property if a wide range of wettability are employed. This study focused on the effect of surface wettability on fibroblast adhesion over a wide range of wettability using a single material without changing surface topography. Plasma polymerization with hexamethyldisiloxane followed by oxygen (O2)‐plasma treatment was employed to modify the surfaces. The water contact angle of sample surfaces varied from 106° (hydrophobicity) to almost 0° (super‐hydrophilicity). O2 functional groups were introduced on polymer surfaces during O2‐plasma treatment. The cell attachment study confirmed that the more hydrophilic the surface, the more fibroblasts adhered in the initial stage that includes super‐hydrophilic surfaces. Cells spread much more widely on the hydrophilic surfaces than on the hydrophobic surfaces. There was no significant difference in fibroblast proliferation, but cell spreading was much greater on the hydrophilic surfaces. The fibronectin adsorbed much more on a hydrophilic surface while albumin dominated on a hydrophobic surface in a competing mode. These findings suggest the importance of the surface wettability of biomaterials on initial cell attachment and spreading. The degree of wettability should be taken into account when a new biomaterial is to be employed. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [ABSTRACT FROM AUTHOR]

Background: Osteonecrosis of the femoral head (ONFH) is one of the major side effects of corticosteroid therapy. Because corticosteroids are metabolized by hepatic cytochrome P450 (CYP) 3A, a low endogenous activity of this enzyme may contribute to the pathogenesis of ONFH. The purpose of this study was to examine the possible association of hepatic CYP3A activity and the susceptibility to ONFH in patients treated with corticosteroids.Methods: In this prospective controlled study we measured the clearance of intravenous midazolam (0.25 mg/kg) to estimate hepatic CYP3A activity in patients with steroid-induced ONFH (n = 26), patients with alcohol-related ONFH (n = 29), and non-ONFH control patients (n = 75) undergoing orthopedic surgery. Midazolam clearance was compared between the groups, and the relationship between the level of hepatic CYP3A activity and the prevalence of ONFH was evaluated by multivariate analysis.Results: Midazolam clearance in patients with steroid-induced ONFH was significantly lower than that in control patients and patients with alcohol-related ONFH (7.7 ± 1.8 mL · kg−1 · min−1 versus 11.4 ± 3.5 mL · kg−1 · min−1 and 10.5 ± 2.8 mL · kg−1 · min−1, respectively; P < .001). Patients with low midazolam clearance (<9.5 mL · kg−1 · min−1) had a 9-fold greater risk for steroid-induced ONFH (adjusted odds ratio, 9.08 [95% confidence interval, 2.79-29.6]; P < .001). Midazolam clearance did not show a significant correlation with the prevalence of alcohol-related ONFH.Conclusions: Low hepatic CYP3A activity may significantly contribute to the risk for steroid-induced ONFH.Clinical Pharmacology & Therapeutics (2006) 80, 396–402; doi: 10.1016/j.clpt.2006.07.004 [ABSTRACT FROM AUTHOR]

The article reports that Japanese children are falling behind previously high levels of educational achievement, partly because early childhood teachers do not have a clear sense of what they should be teaching to prepare children for school. The article traces the history of kindergarten and early childhood education in Japan.

The purpose of this study was to compare the retention force of FRC posts which were built up using direct and direct-indirect fabrication techniques with two fiber-reinforced core build-up systems (FibreKor and i-TFC). Posts were cemented in endodontically treated bovine single roots with resin cement using either direct or direct-indirect technique. Following which, the retention force of post-and-cores and fracture sites were examined. It was found that both the retention force and fracture site depended on the fabrication technique and resin cements. Post-and-cores built up with direct-indirect technique had greater retention force than those fabricated using direct technique. Fracture modes most frequently observed were adhesive failure at Resin/Dentin interface, a mixture of adhesive failures at Post/Resin and Resin/Dentin interfaces as well as cohesive failure of resin cements. Based on the results of this study, we concluded that when it comes to post-and-core build-up for endodontically treated tooth, the direct-indirect technique is more effective than the direct technique on the retention force of FRC posts. [ABSTRACT FROM AUTHOR]

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The purpose of this study was to evaluate the combined effects of citric acid and glutaraldehyde (GA) on the resin bonding to Er : YAG laser‐irradiated dentin. Bovine dentin was prepared with 180‐ to 600‐grit SiC paper and then uniformly irradiated with an Er : YAG laser (laser‐irradiated group) or immersed in water at 60°C for 15 min (heated group). The samples were then acid‐conditioned with 10% citric acid (10‐0) or 10% citric acid/3% ferric chloride (10‐3) for 15 s and treated with GA for 10 min before bonding to an acrylic rod with 4‐META/MMA‐TBB resin. These samples were trimmed to prepare miniaturized dumbbell‐shaped specimens. After storage in water at 37°C for 1 d, the tensile bond strength was measured, and the fractured surface was evaluated using a scanning electron microscope (SEM). In the laser‐irradiated and heated groups, the 10‐3+GA‐treated specimen had higher bond strength than that of 10‐0+GA. On the other hand, the tensile bond strength of 10‐3+GA in the non‐irradiated group was lower that that of 10‐0+GA. In conclusion, the combination of 10‐3 and GA for bonding with 4‐META/MMA‐TBB resin was the most effective for Er : YAG laser‐irradiated dentin and heated dentin, but it was not effective for the non‐irradiated dentin. [ABSTRACT FROM AUTHOR]