OBJECTIVEThis study aimed to synthesize a novel nano-antibacterial inorganic filler that contains a quaternary ammonium salt with long chain alkyl and to report the antibacterial property of dental resin composites.

METHODSA novel nano-antibacterial inorganic filler that contains a quaternary ammonium salt with long chain alkyl was synthesized based on previous research. The antibacterial property of the filler was measured. The surface of the novel nano-antibacterial inorganic filler was modified by a coupling agent to achieve a good interfacial bonding between the filler and the resin matrix. Infrared spectrum analysis was carried out. The modified novel nano-antibacterial inorganic fillers were then incorporated into the dental resin matrix. The dispersion of the fillers was observed and compared with those incorporated into Tetric N-Ceram, a commercial resin composite, under a scanning electron microscope. Streptococcus mutans was used in testing the antibacterial property of the dental resin composites.

RESULTSA quaternary ammonium salt with a long chain alkyl was successfully grafted onto the surface of nano-silica particles. The novel nano-antibacterial inorganic filler that contains quaternary ammonium salt with a long chain alkyl showed stronger antibacterial efficacy than the antibacterial inorganic filler that contains quaternary ammonium salt with a short chain alkyl. The modified novel antibacterial inorganic fillers displayed a homogeneous dispersion in the resin composite bulk and combined closely with the resin matrix, similar to the Tetric N-Ceram. The resin composites that contain novel antibacterial inorganic fillers showed stronger antibacterial effect on Streptococcus mutans compared with the control group.

CONCLUSIONThe novel nano-antibacterial inorganic filler that contains a quaternary ammonium salt with long chain alkyl showed a strong antibacterial property. It also exhibited good compatibility with the dental resin matrix after undergoing coupling treatment.

Acrylic Resins ; Anti-Bacterial Agents ; Composite Resins ; Polyurethanes ; Quaternary Ammonium Compounds ; Streptococcus mutans

As a widely used teaching model in higher medical education,problem-based learning is regard as one of the direction of education revolution in our country.Based on the PBL teaching practice in the second clinical medical college of Guangzhou university of traditional Chinese medicine,the article summarized determination of teaching content,compiling of teaching plan,methods of teaching process and teaching evaluation as well as analyzed some key questions in practicing PBL teaching in seven-year program clinical curriculum.

Objective To explore the diagnostic performance of 64-slice spiral CT combined with exercise treadmill test for coronary artery disease ( CAD). Methods Eighty-six patients suspected of CAD were divided into low risk group, intermediate risk group and high risk group according to estimated pretest probabilities of CAD. All patients underwent coronary angiography, 64-slice spiral CT and exercise treadmill test. With coronary artery stenosis rate >50% as positive findings, the sensitivity, specificity, positive predictive value ( PPV), negative predictive value ( NPV) and accuracy of 64-slice spiral CT and 64-slice spiral CT combined with exercise treadmill test in diagnosis of CAD were calculated. Results With coronary angiography as the "golden criteria", the sensitivity, specificity, PPV, NPV and accuracy of 64-slice spiral CT in diagnosis of CAD were 95.2% , 88.6% , 88.9% , 95.1% and 91.9% , respectively. The sensitivity of low risk group, intermediate risk group and high risk group was 100% , 100% and 92.6%, specificity was 94.4% , 94.1% and 66.7%, PPV was 80.0%, 91.7% and 89.3%, NPV was 100% , 100% and 75.0%, and accuracy was 95.5% , 96.4% and 86.1%, respectively. The sensitivity, specificity, PPV, NPV and accuracy of 64-slice spiral CT combined with exercise treadmill test in diagnosis of CAD were 97.6%, 97.7%, 97.6%, 97.7% and 97.7%, respectively. Conclusion 64-slice spiral CT combined with exercise treadmill test works well in screening CAD, especially for those with a low or intermediate estimated pretest probability.

OBJECTIVETo develop a resin composite incorporated with nano-antibacterial inorganic filler containing long-chain alkyl quaternary ammonium salt, and to measure its effect on human dental plaque microcosm biofilm.

METHODSA novel nano-antibacterial inorganic filler containing long-chain alkyl quaternary ammonium salt was synthesized according to methods introduced in previous research. Samples of the novel nano-antibacterial inorganic fillers were modified by a coupling agent and then added into resin composite at 0%, 5%, 10%, 15% or 20% mass fractions; 0% composite was used as control. A flexural test was used to measure resin composite mechanical properties. Results showed that a dental plaque microcosm biofilm model with human saliva as inoculum was formed. Colony-forming unit (CFU) counts, lactic acid production, and live/dead assay of biofilm on the resin composite were calculated to test the effect of the resin composite on human dental plaque microcosm biofilm.

RESULTSThe incorporation of nano-antibacterial inorganic fillers with as much as 15% concentration into the resin composite showed no adverse effect on the mechanical properties of the resin composite (P > 0.05). Resin composite containing 5% or more nano-antibacterial inorganic fillers significantly inhibited the metabolic activity of dental plaque microcosm biofilm, suggesting its strong antibacterial potency (P < 0.05).

CONCLUSIONThis novel resin composite exhibited a strong antibacterial property upon the addition of up to 5% nano-antibacterial inorganic fillers, thereby leading to effective caries inhibition in dental application.

Anti-Bacterial Agents ; pharmacology ; Biofilms ; drug effects ; Composite Resins ; chemistry ; Dental Caries ; prevention & control ; Dental Plaque ; Humans ; Lactic Acid ; Quaternary Ammonium Compounds ; pharmacology ; Saliva

Objective To evaluate the consistency of psoriasis-involved body surface area (BSA) measurement among raters from different clinical centers after training in a new standard operating procedure (SOP) for involved BSA measurement,so as to provide a method for the evaluation of psoriasis with high accuracy and operability.Methods Firstly,two raters from Guangdong Provincial Hospital of Chinese Medicine (GPHCM) independently and alternately assessed the disease severity in 40 patients with psoriasis after systematic training in the BSA-SOP.Then,one of the raters from GPHCM and 11 raters from 11 subcenters separately assessed the disease severity in 209 patients with psoriasis by using the BSA-SOP,and the consistency was evaluated by using intraclass correlation coefficient (ICC).Results There was a very high degree of consistency in involved BSA values between the 2 raters from GPHCM (ICC =0.989,95％ confidence interval:0.979-0.994).The consistency of involved BSA values for the assessment of psoriasis severity was also high among the rater from GPHCM and the raters from 11 subcenters (ICC ranging from 0.849 to 0.998).Conclusion The raters from different centers showed high consistency of involved BSA measurement for the assessment of psoriasis severity after training in the new BSA-SOP,so the BSA-SOP can serve as a reliable reference for multicenter clinical studies.

Affected by inconsistency of intertemporal preferences,residents prefer an increment time series of medical insurance benefits,and may be interrupted when intertemporal preferences are not met.Based on the characters of intertemporal preferences,to improve medical insurance benefits can take countermeasures such as establishing dynamic insurance benefits adjustment mechanism,combining benefits improvement with strengthening supervision,effectively controlling medical expenses to substantially improve the medical benefits,and introducing alternative risk transfer ways etc.

Affected by inconsistency of intertemporal preferences,residents prefer an increment time series of medical insurance benefits,and may be interrupted when intertemporal preferences are not met.Based on the characters of intertemporal preferences,to improve medical insurance benefits can take countermeasures such as establishing dynamic insurance benefits adjustment mechanism,combining benefits improvement with strengthening supervision,effectively controlling medical expenses to substantially improve the medical benefits,and introducing alternative risk transfer ways etc.

Affected by inconsistency of intertemporal preferences,residents prefer an increment time series of medical insurance benefits,and may be interrupted when intertemporal preferences are not met.Based on the characters of intertemporal preferences,to improve medical insurance benefits can take countermeasures such as establishing dynamic insurance benefits adjustment mechanism,combining benefits improvement with strengthening supervision,effectively controlling medical expenses to substantially improve the medical benefits,and introducing alternative risk transfer ways etc.

Affected by inconsistency of intertemporal preferences,residents prefer an increment time series of medical insurance benefits,and may be interrupted when intertemporal preferences are not met.Based on the characters of intertemporal preferences,to improve medical insurance benefits can take countermeasures such as establishing dynamic insurance benefits adjustment mechanism,combining benefits improvement with strengthening supervision,effectively controlling medical expenses to substantially improve the medical benefits,and introducing alternative risk transfer ways etc.

Affected by inconsistency of intertemporal preferences,residents prefer an increment time series of medical insurance benefits,and may be interrupted when intertemporal preferences are not met.Based on the characters of intertemporal preferences,to improve medical insurance benefits can take countermeasures such as establishing dynamic insurance benefits adjustment mechanism,combining benefits improvement with strengthening supervision,effectively controlling medical expenses to substantially improve the medical benefits,and introducing alternative risk transfer ways etc.