Studies on the effect of ultrasound on properties and bonding strength of dentin smear layer / 口腔医学

Objective@# To explore the effect of ultrasound on dentin smear layer's surface and bonding strength of the universal resin adhesive under self-etching mode. @*Methods@# Forty mandibular third molars without caries were randomly divided into two groups; one was polished with silicon carbide sandpaper; the other was polished with silicon carbide sandpaper followed by ultrasonic treatment. Scanning electron microscope (SEM) was used to observe surface of the dentin. Treated teeth were bonded with two universal resin adhesives, Clearfil Universal Bond (pH=2.3) and All-Bond Universal (pH=3.1), and the penetration of the bonding interface was observed with a confocal laser scanning microscope (CLSM) after Rhodamine B staining. Finally, the micro tensile bond strength test was conducted to test the adhesion. @*Results@# The SEM showed that after polishing with silicon carbide sandpaper, the smear layer of the dentin surface was scratched, and dentin tubules were almost completely blocked, with no obvious dentin tubules exposed. After ultrasonic treatment, the scratches were reduced, and a large number of dentin tubules were exposed. CLSM showed that both adhesives could penetrate the dentin along the dentin tubules more deeply after ultrasound treatment. Micro tensile bond strength tests showed that ultrasonic treatment could enhance the bonding strength of two universal resin adhesives. However, there was no statistical difference in bonding strength between these two universal resin adhesives under the same treatment. .@*Conclusion@# Ultrasound can partially remove the smear layer on dentin's surface, expose dentin tubules, and increase universal resin adhesives' penetration depth and bonding strength under self-etching mode

The Role and Requirement of Datasets in the Quality Control of Artifcial Intelligence Medical Device / 中国医疗器械杂志

Artificial intelligence is a blooming branch of medical device. Its development and quality control all rely on high quality clinical data. Since there is no established standard or guidance yet, it is important to study how to build and utilize a dataset appropriately and scientifically, especially for the decrease of clinical trial expense. With reference to the current status of premarket review and related guidance in developed countries, this paper analyzes the role and requirement of datasets in the quality control of AI medical device, providing useful information for regulation agencies and the development of public datasets for AI.

Research on bond durability among different core materials and zirconia ceramic cemented by self-adhesive resin cements / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This research estimated shear bond durability of zirconia and different substrates cemented by two self-adhesive resin cements (Clearfil SA Luting and RelyX U100) before and after aging conditioning.</p><p><b>METHODS</b>Machined zirconia ceramic discs were cemented with four kinds of core material (cobalt-chromium alloy, flowable composite resin core material, packable composite resin, and dentin) with two self-adhesive resin cements (Clearfil SA Luting and RelyX U100). All specimens were divided into eight test groups, and each test group was divided into two subgroups. Each subgroup was subjected to shear test before and after 10 000 thermal cycles.</p><p><b>RESULTS</b>All factors (core materials, cements, and thermal cycle) significantly influenced bond durability of zirconia ceramic (P<0.00 1). After 10 000 thermal cycles, significant decrease was not observed in shear bond strength of cobalt-chromium alloy luted with Clearfil SA Luting (P>0.05); observed shear bond strength was significantly higher than those of other substrates (P<0.05). Significantly higher shear bond strength was noted in Clearfil SA Luting luted with cobalt-chromium alloy, flowable composite resin core material, and packable composite resin than that of RelyX U100 (P<0.05). However, significant difference was not observed in shear bond strength of dentin luted with Clearfil SA Luting and RelyX U100 (P>0.05).</p><p><b>CONCLUSIONS</b>Different core materials and self-adhesive resin cements can significantly affect bond durability of zirconia ceramic. 
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The effects of shade and light irradiation on the polymerization of composite resin core materials / 实用口腔医学杂志

Objective:To evaluate the effects of shade and light irradiation condition on the polymerization of composite resin core material.Methods:The light-proof silicon rubber cuboid mold with one end open were stringed and filled by dual-cured flowable composite resin core material with the shade of dentine and white(Paracore) respectively,then the open end of mold was irradiated directly by a light unit at 1 000 mW/cm2 ×20 s and 3 200 mW/cm2 ×6 s respectively.And all specimens of 4 groups(n =5) were stored in the light-proof box.1 h and 24 h after irradiation,Knoop microhardness was measured along the vertical surfaces of the specimens at the depth of 1,2 and 3 mm respectively.Data were analyzed by One-way ANOVA.Results:At all light irradiation conditions,the hardness of all specimens decreased with the increase of measurement depth.24 h after irradiation,the hardness of dentine shade specimens at each measurement depth showed no difference between 1 000 mW/cm2 × 20 s and 3 200 mW/cm2 × 6 s irradiation,while the white shade specimens irradiated by 1 000 mW/cm2 × 20 s showed higher hardness than those by 3 200 mW/cm2 × 6 s.Conclusion:To obtain sufficient polymerization of composite core material with different shade optimal light irradiation condition should be selected.

Effect of a chemical primer on the bond strength of a zirconia ceramic with self-adhesive resin cement / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the bond strength and durability of a self-adhesive resin cement with a zirconia ceramic pretreated by a zirconia primer.</p><p><b>METHODS</b>Zirconia ceramic (Vita Inceram YZ) plates with a thickness of 2.5 mm were fired, polished, and then cleaned. Half of the polished ceramic plates were sandblasted with 50 μm alumina particles at 0.3 MPa for 20 s. The surface compound weight ratios were measured via X-ray fluorescence microscopy. The polished and sandblasted ceramic plates were directly bonded with self-adhesive resin cement (Biscem) or were pretreated by a zirconia primer (Z Primer Plus) before bonding with Biscem. The specimens of each test group were divided into two subgroups (n=10) and subjected to the shear test after 0 and 10,000 thermal cycles. The data were analyzed via three-way ANOVA.</p><p><b>RESULTS</b>After air abrasion, 8.27% weight ratio of alumina attached to the zirconia surface. Compared with air abrasion, primer treatment more significantly improved the primary resin bond strength of the zirconia ceramic. The primary resin bond strength of the zirconia ceramic with no primer treatment was not affected by thermocycling (P>0.05). However, the primary resin bond strength of the zirconia ceramic with primer treatment was significantly decreased by thermocycling (P<0.05).</p><p><b>CONCLUSION</b>Primer treatment can improve the primary resin bond strengths of zirconia ceramics. However, the bond interface of the primer is not stable and rapidly degraded during thermocycling.</p>

Quality control research of cold light source of endoscope / 中国医疗器械杂志

This paper introduced the significance parameters of the quality control of cold light source of endoscope, expounded the importance and necessity of quality control of cold light source; it investigated several manufacturers, analyzed and discussed the main causes of the cold light source uneven, in order to realized the standard management and effective supervision on the cold light source, at the end, the next step quality control work was brought out, which provide technical support for quality supervision of cold light source.

Clinical evaluation of zirconia crowns for single posterior teeth / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe and evaluate the clinical performance of zirconia crowns made by CEREC inLab computer aided design/computer aided manufacturing(CAD/CAM) for posterior teeth.</p><p><b>METHODS</b>A total of 242 patients were implanted with zirconia crowns fabricated by CEREC inLab CAD/CAM. The crowns were evaluated by Modified US Public Health Service criteria at baseline, 6, 12, 24, and 36 months. The chi-square test was used to analyze the survival rate.</p><p><b>RESULTS</b>All but five crowns were evaluated by an independent evaluator at baseline, 6, 12, 24, and 36 months. The survival rate declined with time. The A score percentage was above 85% at 36 months.</p><p><b>CONCLUSION</b>The single zirconia crowns fabricated by CEREC inLab CAD/CAM demonstrate satisfactory clinical performance during a short period.</p>

Influence of long-term water storage on the physical and chemical properties of four different dental cements / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate and compare the physical and chemical properties of four different dental cements under long-term water storage.</p><p><b>METHODS</b>A glass-ionomer cement (A:Fuji I), a resin reinforced glass-ionomer (B: Fuji Plus), a self-adhesive resin cement (C:G-Cem), and an etch & rinse resin cement (D: Duolink) were taken as samples. According to ISO 4049, water sorption and solubility of four resin cements under different storage times (1 week, 1, 3, 6 and 12 months) were calculated (n = 5), meanwhile their surface Knoop micro hardness values were measured.</p><p><b>RESULTS</b>Surface cracks were detected on sample B and C after 12 months. Sample A was fragmentized after 6 months. Sample B showed significantly lower surface hardness after 12 months than it did after the first 24 hours of water storage (P < 0.05). Sample D showed significantly lower water sorption than other cements did at all exam time point. The highest water sorption values were observed in Sample D after 1 month [(40.8±2.5) µg/mm(3)], in Sample B after 3 months [(551.3±22.5) µg/mm(3)], in Sample C after 12 months [(147.5±8.3) µg/mm(3)]. The highest solubility values were detected in Sample B after 3 months [(105.3±10.5) µg/mm(3)], in Sample C after 12 months [(79.3 ± 6.2) µg/mm(3)], and in Sample D after 12 months [(23.9 ± 6.9) µg/mm(3)].</p><p><b>CONCLUSIONS</b>Among the four types of cements, the etch & rinse resin cement showed the best stability of physical and chemical properties under long-term water storage.</p>

Key points in anterior esthetic restorations with all ceramic / 华西口腔医学杂志

This paper introduced the key points in fabricating anterior esthetic restorations with all ceramic materials, including pre-operative smile design, standard tooth preparation, provisional restoration fabrication, all ceramic materials selection, all ceramic restoration bonding, ceramic crack and fracture prevention. And then, the authors summarized and reviewed the clinical common problems in anterior esthetic restorations.

Hardness development of self-adhesive resin cement in simulated root canal / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To compare the hardness development of dual-cured self-adhesive and universal resin cement in simulated root canal.</p><p><b>METHODS</b>The light-proof half-cylinder steel slot with one end open were syringed and filled respectively by self-adhesive A (RelyX Unicem), B (BisCem) and universal C (DUOLINK) resin cements, then the open end of slot was irradiated directly by a light unit for 20 s. Specimens were stored in a light-proof box for 0.5 h, Knoop microhardness was measured along the vertical surfaces of specimens from 1 mm to 10mm depth at 1 mm intervals. The same measurements were taken at 24 h and 120 h after irradiation. Data were analyzed by One-way ANOVA.</p><p><b>RESULTS</b>Hardness of each group decreased with the increase of simulated canal depth (P<0.001), however hardness showed no significant change between 5 mm and more depth of group A, between 4 mm and more depth of group B and C. The increase of hardness for each group was more rapid within 0.5 h after irradiation, thereafter the hardness increased gradually to maximum at 24 h. At 120 h after irradiation, hardness of group C was greater than that of other two groups at more than 1 mm depth (P<0.001).</p><p><b>CONCLUSION</b>Under dual-cured condition, hardness has significant difference between self-adhesive and universal resin cements, however their hardness development is similar.</p>

Influence of different resin bond systems on coronal microleakage of fiber posts and core restorations / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the coronal microleakage of teeth restored with fiber posts and composite cores with four different resin bonding systems.</p><p><b>METHODS</b>Sixty extracted human maxillary single-rooted teeth were endodontically treated and randomly divided into four groups. Post spaces were prepared in the root canals. Four different resin bonding systems (RelyX Unicem, Dulink, DC core Automix, Luxacore) were used respectively to bond fiber posts and reconstruct cores. The specimens were immersed in India ink for one week. Subsequently all teeth were demineralized, dehydrated and rendered transparent. Then microleakage was observed with stereomicroscope.</p><p><b>RESULTS</b>The microleakage degrees among four resin bonding systems were significantly different (P = 0.007), and group C showed the least microleakage compared with the other three.</p><p><b>CONCLUSION</b>Self-etching resin bonding systems have a super margin sealing ability.</p>

Modified retropubic prostatectomy for the treatment of benign prostatic hyperplasia / 中国基层医药

Objective To evaluate modified retropubic prostatectomy in the treatment of benign prostatic hyperplasia.Methods Modified retropubic prostatectomy was carried out for 56 cases of benign prostatic hyperplasia and the patients were followed up for 1～24 months.Results The procedure were satisfactory in all with less complication.Conclusion Modified retropubic prostatectomy is belived to be the idea surgical procedure for the treatment of benign prostatic hyperplasia.

High sensitive Serum C-reaction protein in macrovascular disease with or without type 2 diabetes / 中国康复理论与实践

@#ObjectiveTo observe the changes of high sensitive serum C-reaction protein (hsCRP) in macrovascular disease with or without type 2 diabetes.MethodsThere were 3 groups population in our study:148 type 2 diabetic patients were divided into 2 subgroups:77 patients with macrovascular disease and 71 without macrovascular disease, 73 non-diabetic patients with macrovascular disease and 75 health controls. The concentration of serum hsCRP of all patients were determined by ELISA.ResultsThere was significant difference in concentration of serum hsCRP between type 2 diabetes with or without macrovascular disease groups, non-diabetes macrovascular disease group and control(P<0.01 or P<0.001). However, there was not significant difference between 2 diabetes groups and non- diabetic macrovascular disease group(P>0.05). There was no significant difference in hsCRP between type 2 diabetes with and without macrovascular disease (P>0.05).ConclusionThere may be a chronic inflammatory reaction in patients with type 2 diabetes or macrovascular disease. hsCRP might be a well forecasting factor of the occurrence and development of type 2 diabetes and atherosclerosis.