Examining the etiological factors resulting in retinal detachment following prophylactic vitrectomy in the context of acute retinal necrosis syndrome.

OBJECTIVE: The aim of this study is to elucidate the factors contributing to the occurrence of retinal detachment (RD) following prophylactic vitrectomy in cases of acute retinal necrosis (ARN) syndrome. METHODS: A retrospective examination was undertaken, encompassing the medical records of patients diagnosed with ARN who underwent prophylactic vitreous intervention at the Ophthalmology Department of Wuhan University Renmin Hospital East Campus between October 2019 and September 2023. Subsequently, patients who manifested RD in the postoperative period were identified, and a comprehensive analysis was conducted to ascertain the factors underlying the occurrence of RD post-surgery. RESULTS: This study comprised 14 cases (involving 14 eyes) of patients diagnosed with ARN who underwent prophylactic vitreous intervention. The findings revealed that 4 patients experienced postoperative RD, resulting in an incidence rate of 28.57%. Notably, among these cases, 3 cases of RD manifested in the presence of silicone oil, while 1 case occurred subsequent to the removal of silicone oil. All 4 cases of RD exhibited varied degrees of proliferative vitreoretinopathy. Following the occurrence of RD, all patients underwent a secondary vitreous intervention coupled with silicone oil tamponade, leading to successful reattachment of the retina. However, despite these interventions, there was no significant enhancement observed in postoperative visual outcomes when compared to preoperative levels. CONCLUSION: RD following prophylactic vitrectomy in cases of ARN is not an infrequent occurrence and is primarily linked to the postoperative onset of proliferative vitreoretinopathy.

Outcome of chairside CAD/CAM ceramic restorations on endodontically treated posterior teeth: a prospective study.

OBJECTIVE: The aim of this study was to evaluate the outcome and risk factors for chairside CAD/CAM full cusp coverage restorations on endodontically treated posterior teeth after 3 years of follow-up. METHODS: A total of 245 endodontically treated posterior teeth of 224 patients were included and restored with CAD/CAM full cusp coverage all-ceramic restorations according to a standardized protocol. Patients were recalled after treatments 1 to 3 years and underwent clinical and radiological examinations. At recall, modified FDI criteria were used to determine treatment outcomes by 2 evaluators. Success was determined when FDI scores were 1-2, and failure was indicated when FDI scores were 5. Logistic regression analysis was performed to evaluate potential risk factors. RESULTS: A total of 183 patients presented at recall, and the clinical outcomes of 201 teeth were analyzed with a recall rate of 82.0% for teeth and 81.7% for patients after 1-3 years of follow-up.185 of 201 teeth were found to have FDI scores of 1-2, and the success rate was 92%. No teeth were extracted during the follow-up period. Fourteen failed cases with an FDI score of 5 presented restoration dislocation, fracture of restoration or/and tooth. Logistic regression analysis revealed that oral parafunction (OR 2.281, 95% CI 2.2 ~ 47.5, P value 0.01) was a risk factor for success rate. CONCLUSION: Chairside CAD/CAM all-ceramic full cusp coverage restoration was (could be) a promising alternative for restoring endodontically treated posterior teeth.

Abatement of Aromatic Contaminants from Wastewater by a Heat/Persulfate Process Based on a Polymerization Mechanism.

A novel approach to the abatement of pollutants consisting of their conversion to separable solid polymers is explored by a heat/persulfate (PDS) process for the treatment of high-temperature wastewaters. During this process, a simultaneous decontamination and carbon recovery can be achieved with minimal use of PDS, which is significantly different from conventional degradation processes. The feasibility of this process is demonstrated by eight kinds of typical organic pollutants and by a real coking wastewater. For the treatment of the selected pollutants, 30.2-91.9% DOC abatement was achieved with 24.8-91.2% carbon recovery; meanwhile, only 5.2-47.0% of PDS was consumed compared to a conventional degradation process. For the treatment of a real coking wastewater, 71.0% DOC abatement was achieved with 66.0% carbon recovery. With phenol as a representative compound, our polymerization-based heat/PDS process is applicable in a wide pH range (3.5-9.0) with a carbon recovery of >87%. Both SO4•- and HO• can be initiators for polymerization, with different contribution ratios under various conditions. Phenol monomers are semioxidized to form phenolic radicals, which are polymerized via chain transfer or chain growth processes to form separable solid phenol polymers, benzenediol polymers, and cross-linked polymers.

High-fat diet-induced metabolic syndrome increases ligature-induced alveolar bone loss in mice.

BACKGROUND: It has been well documented that metabolic syndrome (MetS) increases severity of periodontitis. In this study, we determined the effect of high-fat diet (HFD)-induced MetS on alveolar bone loss in a mouse model with ligature-induced periodontitis. To understand how MetS increases bone loss, we tested our hypothesis that palmitic acid (PA), a most abundant saturated fatty acid in the HFD, interacts with lipopolysaccharide (LPS) to promote osteoclastogenesis. METHODS: We induced MetS by feeding mice HFD for 18 weeks and induced periodontitis with ligature placement. After treatments, we assessed alveolar bone loss using micro-computed tomography and determined osteoclastogenesis using tartrate-resistant acid phosphatase (TRAP) staining. To explore the mechanisms, we treated macrophages with PA, LPS or both and analyzed the osteoclast formation and cytokine expression in macrophages. RESULTS: While ligature robustly induced periodontitis in mice with or without MetS, the mice with MetS had more bone loss than those without MetS. PA and LPS cooperatively induced osteoclast formation and stimulated the expression of inflammatory cytokines involved in osteoclastogenesis potentially via a FAT/CD36-dependent mechanism in macrophages. CONCLUSIONS: HFD-induced MetS increases alveolar bone loss in mice with ligature-induced periodontitis, and PA and LPS cooperatively stimulate osteoclast formation and proinflammatory gene expression in macrophages.

Prenatal High-Fat Diet Combined with Microplastic Exposure Induces Liver Injury via Oxidative Stress in Male Pups.

Prenatal high-fat diet (HFD) or exposure to microplastics can affect the accumulation of liver fat in offspring. We sought to determine the effects of maternal HFD intake and microplastic exposure on fatty liver injury through oxidative stress in pups. Pregnant female Sprague-Dawley rats were randomly divided into maternal HFD (experimental group) or normal control diet (NCD; control group) groups with or without microplastic exposure. As a result, the following groups were established: HFD-L (HFD + microplastics, 5 µm, 100 µg/L), HFD-H (HFD + microplastics, 5 µm, 1000 µg/L), NCD-L (NCD + microplastics, 5 µm, 100 µg/L), and NCD-H (NCD + microplastics, 5 µm, 1000 µg/L). The pups were sacrificed on postnatal day 7 (PD7). Liver histology revealed increased hepatic lipid accumulation in pups in the HFD-L and HFD-H groups compared to those in the HFD, NCD-L, NCD-H, and NCD groups on PD7. Similarly, liver TUNEL staining and cellular apoptosis were found to increase in pups in the HFD-L and HFD-H groups compared to those in the HFD, NCD-L, NCD-H, and NCD groups. The expression levels of malondialdehyde, a lipid peroxidation marker, were high in the HFD, HFD-L, and HFD-H groups; however, the highest expression was observed in the HFD-H group (p < 0.05). The levels of glutathione peroxidase, an antioxidant enzyme, decreased in the HFD, HFD-L, and HFD-H groups (p < 0.05). Overall, oxidative stress with cellular apoptosis plays a vital role in liver injury in offspring after maternal intake of HFD and exposure to microplastic; such findings may shed light on future therapeutic strategies.

The Presence of Periodontitis Exacerbates Non-Alcoholic Fatty Liver Disease via Sphingolipid Metabolism-Associated Insulin Resistance and Hepatic Inflammation in Mice with Metabolic Syndrome.

Clinical studies have shown that periodontitis is associated with non-alcoholic fatty liver disease (NAFLD). However, it remains unclear if periodontitis contributes to the progression of NAFLD. In this study, we generated a mouse model with high-fat diet (HFD)-induced metabolic syndrome (MetS) and NAFLD and oral P. gingivalis inoculation-induced periodontitis. Results showed that the presence of periodontitis increased insulin resistance and hepatic inflammation and exacerbated the progression of NAFLD. To determine the role of sphingolipid metabolism in the association between NAFLD and periodontitis, we also treated mice with imipramine, an inhibitor of acid sphingomyelinase (ASMase), and demonstrated that imipramine treatment significantly alleviated insulin resistance and hepatic inflammation, and improved NAFLD. Studies performed in vitro showed that lipopolysaccharide (LPS) and palmitic acid (PA), a major saturated fatty acid associated with MetS and NAFLD, synergistically increased the production of ceramide, a bioactive sphingolipid involved in NAFLD progression in macrophages but imipramine effectively reversed the ceramide production stimulated by LPS and PA. Taken together, this study showed for the first time that the presence of periodontitis contributed to the progression of NAFLD, likely due to alterations in sphingolipid metabolism that led to exacerbated insulin resistance and hepatic inflammation. This study also showed that targeting ASMase with imipramine improves NAFLD by reducing insulin resistance and hepatic inflammation.

Cost-effectiveness analysis: nonsurgical root canal treatment versus single-tooth implant.

BACKGROUND: Economic evaluation of nonsurgical root canal treatment (NSRCT) and single-tooth implant (STI) provides useful information for medical decision. This retrospective study aimed to evaluate the cost-effectiveness of NSRCT versus single-tooth implant (STI) after 5-year treatment in a university affiliated hospital in Beijing, China. METHODS: 211 patients who underwent NSRCT and 142 patients who had STI were included and recalled after 5-year treatment. The propensity scores were used to match the cases of two treatment modalities. At recall, outcomes were determined based on clinical and radiographical examinations. For endodontically treated cases, absence or reduction of radiolucency were defined as success. Marginal bone loss (MBL) ≤ 4 mm were determined as success for implant cases. Direct and indirect costs were calculated in China Yuan (CNY). Patients' willingness to pay (WTP) for each treatment modality was evaluated by questionnaires. A cost-effectiveness analysis was performed from the societal perspective. RESULTS: 170 patients with 120 NSRCT teeth and 96 STI were available at recall. Based on propensity score matching, 76 endodontically treated teeth were matched to 76 implants. Absence of the radiolucency was observed in 58 of 76 endodontically treated teeth (76%) and reduction of the radiolucency in 9 of 76 teeth (12%) and altogether the success rate was 88%. 100% implants were detected with marginal bone loss (MBL) ≤ 4 mm. The cost advantage of NSRCT (4,751 CNY) over STI (20,298 CNY) was more pronounced. Incremental cost effectiveness ratio (ICER) was 129,563 CNY (STI-NSRCT) per success rate gained. It exceeded the patients' willingness to pay value 7,533 CNY. CONCLUSIONS: Clinical outcomes of NSRCT and STI could be predictable after 5-year treatment. NSRCT may be more cost-effective than STI for managing endodontically diseased teeth.

[Quality Evaluation of Temporomandibular Joint Images from 3 High-resolution Dynamic Sequences].

Objective To compare the image quality of three high-resolution dynamic MRI methods for evaluating the motion of temporomandibular joint disc and condyle. Methods Twenty-five patients with suspected temporomandibular joint disorders were examined by single-shot fast spin-echo (SSFSE),fast imaging employing steady-state acquisition (FIESTA),and spoiled gradient echo (SPGR) on the oblique sagittal position.Two radiologists performed subjective and objective evaluation on the images with double-blind method.The subjective evaluation included the signal intensity of mandibular condyle,articular disc,soft tissue around articular disc,and lateral pterygoid muscle,the contrast between articular disc and condyle,the contrast between articular disc and surrounding soft tissue,condylar motion,and disc movement.The objective evaluation indexes included image signal intensity,signal-to-noise ratio (SNR),and contrast-to-noise ratio (CNR).The subjective and objective indexes of the image quality were compared between the three sequences. Results The SSFSE sequence had lower signal intensity of articular disc and higher signal intensity of condyle and surrounding soft tissue than FIESTA and SPGR sequences (all P<0.001).The SPGR sequence showed higher signal intensity of lateral pterygoid muscle than the SSFSE and FIESTA sequences (P=0.017,P<0.001).Among the three sequences,SSFSE sequence showed the clearest articular disc structure (χ2=41.952,P<0.001),the strongest contrast between articular disc and condyle (χ2=35.379,P<0.001),the strongest contrast between articular disc and surrounding soft tissue (χ2=27.324,P<0.001),and the clearest movement of articular disc (χ2=44.655,P<0.001).SSFSE and FIESTA sequences showed higher proportion of disc displacement and reduction than SPGR sequence (all P<0.001).The CNR (χ2=21.400,P<0.001),SNR (χ2=34.880,P<0.001),and condyle signal intensity (F=337.151,P<0.001) demonstrated differences among SSFSE,FIESTA,and SPGR sequences.The CNR of SSFSE sequence was higher than that of FIESTA sequence (P<0.001),while it had no significant difference between SSFSE and SPGR sequences (P=0.472).In addition,the SSFSE sequence had higher SNR and signal intensity than FIESTA and SPGR sequences (all P<0.001). Conclusion The best image quality can be observed from SSFSE sequence where both the structure and movement of temporomandibular joint are well displayed.Therefore,SSFSE is preferred for the examination of temporomandibular joint movement.

Effects of different concentrations and types of microplastics on bacteria and fungi in alkaline soil.

The threat of microplastic (MP) pollution of soil ecosystems has aroused global concern; however, relatively few studies have focused on the effects of MPs on both bacterial and fungal communities in soil. In this study, a 310-day soil incubation experiment was designed to examine the effects of 7% and 14% (W/W) polyethylene (PE), polystyrene (PS), and polyvinyl chloride (PVC) MPs on soil enzyme activities and soil bacterial as well as fungal communities. The findings revealed that all three kinds of MPs stimulated soil enzyme activities, with 14% PVC, 7% PS, and 14% PE having the greatest impact on the activities of catalase, urease, and alkaline phosphatase. MPs did not change the types but the relative abundance of these phyla in soil. MPs mainly increased the abundance of Proteobacteria, Actinobacteria, and Ascomycota as well as declined the abundance of Acidobacteria, Basidiomycota, and Chytridiomycota. The response of fungi to MPs was stronger than that of bacteria, and the diversity of fungal communities was more sensitive to the impact of MPs than that of bacterial communities. PVC had the greatest impact on the diversity of microbial communities. PICRUSt analysis revealed that MPs mainly promoted the metabolic function of soil bacteria. Based on the FUNGuid tool, it was found that MPs had significant effects on fungi, which were closely related to plant growth. These results indicate that the impact of MPs on soil microbial communities depends on the type and concentration of MPs and that bacteria and fungi are affected differently by MPs. Future studies could be focused on the different effects of MPs on fungi and bacteria, and what effect will this difference have on plant growth.

Inhibition of sphingosine-1-phosphate receptor 2 attenuated ligature-induced periodontitis in mice.

OBJECTIVES: Periodontitis is an inflammatory bone loss disease initiated by oral bacterial inflammation. Herein, we determined whether inhibition of sphingosine-1-phosphate receptor 2 (S1PR2, a G protein-coupled receptor) by its specific antagonist, JTE013, could alleviate ligature-induced periodontitis in mice. MATERIALS AND METHODS: C57BL/6 mice were placed with silk ligatures at the left maxillary second molar to induce experimental periodontitis. Mice were treated with JTE013 or control vehicle (dimethyl sulfoxide, DMSO) oral topically on the ligatures once daily. After 15 days of treatment, RNA was extracted from the lingual mucosal tissues to quantify IL-1ß, IL-6, and TNF mRNA levels in the tissues. Alveolar bone loss was determined by micro-computed tomography. Sagittal periodontal tissue sections were cut and stained by hematoxylin and eosin (H&E) for general histology, or stained by tartrate-resistant acid phosphatase (TRAP) for osteoclasts. RESULTS: Treatment with JTE013 attenuated ligature-induced alveolar bone loss compared with DMSO treatment. Treatment with JTE013 reduced IL-1ß, IL-6, and TNF mRNA levels in murine gingival mucosal tissues, inhibited leukocyte infiltration in the periodontal tissues, and decreased the number of osteoclasts in the periodontal tissues compared with controls. CONCLUSION: Oral topical administration of JTE013 alleviated periodontal inflammatory bone loss induced by ligature placement in mice.

Zwitterionic Polymer Conjugated Glucagon-like Peptide-1 for Prolonged Glycemic Control.

Glucagon-like peptide-1 (GLP-1) is of particular interest for treating type 2 diabetes mellitus (T2DM), as it induces insulin secretion in a glucose-dependent fashion and has the potential to facilitate weight control. However, native GLP-1 is a short incretin peptide that is susceptible to fast proteolytic inactivation and rapid clearance from the circulation. Various GLP-1 analogs and bioconjugation of GLP-1 analogs have been developed to counter these issues, but these modifications are frequently accompanied by the sacrifice of potency and the induction of immunogenicity. Here, we demonstrated that with the conjugation of a zwitterionic polymer, poly(carboxybetaine) (pCB), the pharmacokinetic properties of native GLP-1 were greatly enhanced without serious negative effects on its potency and secondary structure. The pCB conjugated GLP-1 further provided glycemic control for up to 6 days in a mouse study. These results illustrate that the conjugation of pCB could realize the potential of using native GLP-1 for prolonged glycemic control in treating T2DM.

Long noncoding RNA C21orf121/bone morphogenetic protein 2/microRNA-140-5p gene network promotes directed differentiation of stem cells from human exfoliated deciduous teeth to neuronal cells.

Previous studies have revealed that long noncoding RNA (lncRNA) and microRNA play a crucial role in autism, which is a childhood neurodevelopmental disorder with complicated genetic origins. Hence, the study concerns whether lncRNA C21orf121/bone morphogenetic proteins 2 (BMP2)/miR-140-5p gene network affects directed differentiation of stem cells from human exfoliated deciduous teeth (SHED) to neuronal cells in rats with autism. Autism models were successfully established. The neuron cells that differentiated from SHED cell were identified. The expression of lncRNA C21orf121, miR-140-5p, BMP2, Nestin, ßIII-tubulin, and microtubule-associated protein 2 (MAP2) and the expression of neuron-specific enolase (NSE) were examined. Besides, the gap junction (GJ) function of SHED, the intracellular free Ca 2+ concentration, and the social behavior and repetitive stereotyped movements of rats in autism were detected. The target relationship between lncRNA C21orf121 and miR-140-5p and that between miR-140-5p and BMP2 were also verified. Firstly, we successfully isolated SHED and identified the differentiated neurons of SHED. Besides, the expression of BMP2, MAP2, Nestin, ßIII-tubulin, NSE positive rate, GJ function, and intracellular free Ca 2+ concentration were increased with the upregulation of C21orf121 and downregulation of miR-140-5p, and accumulated time of repetitive stereotyped movements decreased and the frequency of social behavior increased. The results indicate that lncRNA C21orf121 as a competing endogenous RNA competes with BMP2 binding to miR-140-5p, thereby promoting SHED to differentiate into neuronal cells via upregulating BMP2 expression.

Risk assessment of toxicants on WHO TobReg priority list in mainstream cigarette smoke using human-smoked yields of Korean smokers.

Recently, the World Health Organization Study Group on Tobacco Product Regulation (WHO TobReg) announced a priority list of 38 toxicants among the more than 7000 chemicals found in cigarette smoke, building upon previous lists of toxicants in cigarette smoke. Here, we conducted a comprehensive study on the quantitative exposure and risk characterization of these priority toxicants in mainstream cigarette smoke listed by the WHO TobReg. The human-smoked toxicant yields estimated from spent cigarette butts of a total of 361 smokers using the part-filter method (PFM) were applied to current exposure and risk estimation for the first time. The PFM can estimate human-smoked yields of toxicants using smokers' maximum mouth-level exposure. The human-smoked yield of each toxicant was converted to systemic uptake by considering bioavailability. Risk indicators-including the incremental lifetime cancer risk (ILCR), cumulative ILCR, hazard quotient (HQ), hazard indices (HIs), and margin of exposure (MOE)-were estimated from the systemic uptake of toxicants combined with Korean exposure factors by gender and age group as well as for total smokers. It was demonstrated that cigarette smoking results in significant cancer and non-cancer health risks. A sensitivity analysis showed that the human-smoked toxicant yield is one of the most important contributors to risk level variations. Our risk estimation suggested that previous risk assessments might have ignored or underestimated the uncertainty of risk assessment. In conclusion, we assessed the risk level of the 38 toxicants on the priority list developed by the WHO TobReg and provided a Korean-specific priority list for the regulations on the emission of cigarette smoke.

Do Open Reduction and Internal Fixation With Articular Disc Anatomical Reduction and Rigid Anchorage Manifest a Promising Prospect in the Treatment of Intracapsular Fractures?

PURPOSE: In response to the increased attention to soft tissue reduction in the treatment of intracapsular condylar fractures (ICFs), a modified open reduction technique is proposed and its functional and radiographic outcomes were evaluated in this study. PATIENTS AND METHODS: This is a retrospective case series study of patients with all ICF types that were treated with open reduction and internal fixation (ORIF) with articular disc anatomic reduction and rigid anchorage. Inclusion and exclusion criteria were strictly applied. Preoperative and postoperative clinical examinations of malocclusion, maximum incisor opening (MIO), laterotrusion, and temporomandibular disorder symptoms were recorded and analyzed. Computed tomography (CT) and magnetic resonance imaging (MRI) were used to assess articular position and condylar morphology and position. RESULTS: Thirty-four patients with ICFs (47 sides) were treated with the modified ORIF technique. At 6 months of follow-up, no malocclusion was found and the MIO considerably expanded to 3.56 ± 0.13 cm. Only 4 patients (12%) had temporomandibular joint discomfort with mouth opening. Interestingly, for unilateral type B ICFs, the laterotrusion distance to the ORIF sides was notably longer than to the non-ORIF sides. Postoperative CT and MRI showed that all fragments were properly reduced and the condyles were in the normal position. Postoperative anterior disc displacement occurred in 4 sides and condylar morphologic abnormalities (slight surface roughening and articular cartilage absorption) occurred in 3 sides (6.4%). CONCLUSIONS: This modified ORIF technique, which achieved good outcomes after treatment of all ICF types, shows promise for the treatment of ICFs.

One Unique 1D Silver(I)-Bromide-Thiol Coordination Polymer Used for Highly Efficient Chemiresistive Sensing of Ammonia and Amines in Water.

Reaction of AgBr with TabHPF6 (TabH = 4-(trimethylammonio)benzenethiol) readily produces a unique one-dimensional coordination polymer [(TabH)(AgBr2)]n (1), consisting of anionic chains [AgBr2]n(n-) with hydrogen bonds to TabH(+) cations. By examining its electrical resistance and stability upon exposure to ammonia and seven common organic amines in water under ambient conditions, compound 1 is found to exhibit good stability and reproducibly high sensitivity toward these analytes at low concentrations. Especially, it can selectively detect NH3 in water with the detection limit as low as 0.05 ppm. This chemiresistive sensing system has the potential for highly efficient monitoring of ammonia and amines responsible for water pollution, eutrophication, food contamination, and industrial hazards.

Three/four-dimensional (3D/4D) microscopic imaging and processing in clinical dental research.

BACKGROUND: Confocal laser scanning microscope (CLSM) has been widely employed in our laboratory for structural and functional analysis of clinical dental specimens and live cell imaging of cultured oral epithelial cells. METHODS: In this vitro study, a Fluoview 1000 (Olympus) confocal system was utilised to study thick sections of carious lesions (40-100 µm) and periodontal disease tissue samples (20-40 µm) by 2D Z stacking imaging and 3-dimentional (3D) reconstruction. Four-dimensional (4D) imaging when including time or position points was used for live cells to assess penetration/localisation/co-localization of oral pathogen proteins and therapeutic drugs. RESULTS: Three-dimensional (3D) reconstruction revealed latent features of carious hard tissues (strongly expressed amelogenin proteins in dentin tubules), and soft tissues (increased glial markers GFAP and S100B in pulp components). We also found the oral microbial specific pathogens, Porphyromonas gingivalis to be widely localised inside the periodontal pocket epithelial tissues as detected by 3D reconstruction from a series of 2D sections from periodontal disease tissue samples. 4D live cell imaging showed the diffusion patterns of fluorescent molecules in response to a bacterial virulence factor, the pathogen (gingipain haemagglutinin) domain that attacked epithelial integrity. This technology also showed uptake of a novel porphyrin-linked metronidazole antibiotic into epithelial cells to kill intracellular oral pathogen, P. gingivalis. CONCLUSIONS: Three/four-dimensional (3D/4D) imaging and processing in confocal microscopy is of great interest and benefit to clinical dental researchers.

[Comparison of effectiveness and safety between Twisted File technique and ProTaper Universal rotary full sequence based on micro-computed tomography].

OBJECTIVE: To evaluate the efficacy and security of two type of rotary nickel titanium system (Twisted File and ProTaper Universal) for root canal preparation based on micro-computed tomography(micro-CT). METHODS: Twenty extracted molars (including 62 canals) were divided into two experimental groups and were respectively instrumented using Twisted File rotary nickel titanium system (TF) and ProTaper Universal rotary nickel titanium system (PU) to #25/0.08 following recommended protocol. Time for root canal instrumentation (accumulation of time for every single file) was recorded. The 0-3 mm root surface from apex was observed under an optical stereomicroscope at 25 × magnification. The presence of crack line was noted. The root canals were scanned with micro-CT before and after root canal preparation. Three-dimensional shape images of canals were reconstructed, calculated and evaluated. The amount of canal central transportation of the two groups was calculated and compared. RESULTS: The shorter preparation time [(0.53 ± 0.14) min] was observed in TF group, while the preparation time of PU group was (2.06 ± 0.39) min (P<0.05). In mid-root level, TF group shaping resulted in less canal center transportation than PU group [(0.070 ± 0.056) mm vs. (0.097 ± 0.084) mm, P<0.05]. No instrument separation was observed in both the groups. Cracks were not found in both the groups either based in micro-CT images or observation under an optical stereomicroscope at 25 × magnification. CONCLUSION: Compared with ProTaper Universal, Twisted File took less time in root canal preparation and exhibited better shaping ability, and less canal transportation.

[Preparation and evaluation of risperidone-loaded microsphere/sucrose acetate isobutyrate in situ forming complex depot with double diffusion barriers].

In the present study, a risperidone loaded microsphere/sucrose acetate isobutyrate (SAIB) in situ forming complex depot was designed to reduce the burst release of SAIB in situ forming depot and to continuously release risperidone for a long-term period without lagime. The model drug risperidone (Ris) was first encapsulated into microspheres and then the Ris-microspheres were embedded into SAIB depot to reduce the amount of dissolved drug in the depot. The effects of different types of microsphere matrix, including chitosan and poly(lactide-coglycolide) (PLGA), matrix/Ris ratios in microspheres and morphology of microspheres on the drug release behavior of complex depot were investigated. In comparison with the Ris-loaded SAIB depot (Ris-SAIB), the complex depot containing chitosan microspheres (in which chitosan/Ris = 1 : 1, w/w) (Ris-Cm-SAIB) decreased the burst release from 12.16% to 5.80%. However, increased drug release rate after 4 days was observed in Ris-Cm-SAIB, which was caused by the high penetration of the medium to Ris-Cm-SAIB due to the hydrophilie of chitosan. By encapsulation of risperidone in PLGA microspheres, most drugs can be prevented from dissolving in the depot and meanwhile the hydrophobic PLGA can reduce the media penetration effect on the depot. The complex depot containing PLGA microspheres (in which PLGA/ drug=4 : 2, w/w) (Ris-Pm-SAIB) showed a significant effectiveness on reducing the burst release both in vitro and in vivo whereby only 0.64% drug was released on the first day in vitro and a low AUC0-4d value [(105.2± 24.4) ng.mL-1.d] was detected over the first 4 days in vivo. In addition, drug release from Ris-Pm-SAIB can be modified by varying the morphology of microspheres. The porous PLGA microspheres could be prepared by adding medium chain triglyceride (MCT) in the organic phase which served as pore agents during the preparation of PLGA microspheres. The complex depot containing porous PLGA microspheres (which were prepared by co-encapsulation of 20% MCT) (Ris-PPm-SAIB) exhibited a slightly increased AUC0-4d of (194.6±15.8) ng.mL-1d and high plasma concentration levels from 4 to 78 days [Cs(4-78d)=(7.8±1.2) ng.mL-1]. The plasma concentration on 78 day C78d was (9.0 2.5) ng.mL-1 which was higher than that of Ris-Pm-SAIB [C78d= (1.6 ± 0.6) ng.mL-1]. In comparison with Ris-Pm-SAIB, the AUC4-78d of Ris-PPm-SAIB increased from (379.0±114.3) ng.mL-1.d to (465.0 ±149.2) ng.mL-1.d, indicating sufficient drug release from the Ris-PPm-SAIB. These results demonstrate that the risperidone loaded porous PLGA microsphere/SAIB in situ forming complex depot could not only efficiently reduce the burst release of SAIB depot both in vitro and in vivo, but also release the drug sufficiently in vivo, and be capable to continuously release the drug for 78 days.

[Comparison of the incidences of apical root cracks after canal preparation with two nickel-titanium rotary systems: an in vitro study].

OBJECTIVE: To compare the incidences of root cracks after canal instrumentation with HyFlex CM system and the ProTaper Universal system. METHODS: Sixty mandibular incisors were mounted in resin blocks with simulated periodontal ligaments, and the apex was exposed. The control group of 20 teeth was not prepared, and the other 40 teeth were divided into 2 experimental groups (n=20). The 40 root canals of the experimental groups were instrumented using HyFlex CM and ProTaper Universal to the major apical foramen (AF). The horizontal sections 1 mm, 2 mm, and 3 mm from the apex were observed under an optical stereomicroscope at 25×magnification. The presence of cracks was noted. RESULTS: No cracks were found in the control teeth. Cracks were found in 1 of 20 (5%) teeth in HyFlex CM group, and 17 of 20 (85%) teeth in ProTaper Universal group. The difference between the two experimental groups was statistically significant (P<0.01). CONCLUSION: The HyFlex CM files caused fewer root cracks than the ProTaper Universal files during the root canal instrumentation.

[Real temperature of the continuous-wave pluggers].

OBJECTIVE: To measure the real temperatures on the pluggers of three continuous-wave devices, and to provide theoretical reference to evaluate thermal damage and heat's influence on the filling materials. METHODS: The dual channel K type thermocouple was contacted to various sizes' pluggers in three different continuous-wave devices (BeeFill, Elements, B&L), and the highest temperatures at different points (tip, and 2 mm, 5 mm, 10 mm from the tip) of the pluggers (preset temperature was 200 °C) were recorded. The measurements were performed 5 times. T-test was used to compare the real temperatures at the tips with that set on the display and one-way ANOVA was used to compare the temperatures of the pluggers in different devices, sizes and points. RESULTS: The highest temperature was at the tip of BeeFill 40/0.03 plugger (198.7±7.7) °C, but there was on statistical differences between that and the preset temperature 200 °C. The temperatures of the remaining pluggers were obviously lower than 200 °C (P<0.05). The lowest temperature of the pluggers was detected at 10 mm from the tip of BeeFill 60/0.06 plugger (69.9±4.0) °C. The highest temperature of each plugger was detected at the tip or 2 mm from the tip (112.1 to 198.7 °C,and the median was 140.8 °C). CONCLUSION: The real temperature of most continuous-wave pluggers included in this study is below the set temperature 200 °C.