Effect of occlusal thickness design on the fracture resistance of endocrowns restored with lithium disilicate ceramic and zirconia / 华西口腔医学杂志

OBJECTIVE@#This study aimed to investigate the effect of occlusal thickness design on fracture resistance of endocrowns restored with lithium disilicate ceramic and zirconia.@*METHODS@#A total of 24 artificial first mandibular molars were randomly divided into four groups with six teeth in each group as follows: group lithium disilicate ceramic-2 mm (lithium disilicate ceramic, with an occlusal thickness of 2 mm and a retainer length of 4 mm); group lithium disilicate ceramic-4 mm (lithium disilicate ceramic, with an occlusal thickness of 4 mm and a retainer length of 2 mm); group zirconia-2 mm (zirconia, with an occlusal thickness of 2 mm and a retainer length of 4 mm); and group zirconia-4 mm (zirconia, with an occlusal thickness of 4 mm and a retainer length of 2 mm). After adhesive cementation (RelyX Ultimate Clicker), all specimens were subjected to thermocycling (10 000 cycles). The specimens were subjected to fracture resistance testing at a 135° angle to the teeth at a crosshead speed of 0.5 mm·min⁻¹ in a universal testing machine. Data were analyzed with ANOVA and Tukey's HSD test by SPSS 15.0. The failure modes were classified.@*RESULTS@#The fracture resistances of groups lithium disilicate ceramic-
2 mm, lithium disilicate ceramic-4 mm, zirconia-2 mm, and zirconia-4 mm were (890.54±83.41), (2 320.87±728.57), 
(2 258.05±557.66), and (3 847.70±495.99) N respectively. Group zirconia-4 mm had the highest fracture resistance, whereas group lithium disilicate ceramic-2 mm had the lowest.@*CONCLUSIONS@#The fracture resistance of molar endocrown with zirconia is higher than that with lithium disilicate ceramic. Increasing the occlusal thickness can improve the fracture resistance but increase the risk of fracture of abutment.

Effects of universal adhesives and resin cement on the shear bond strength of zirconia / 华西口腔医学杂志

OBJECTIVE@#To study the effects of universal adhesives and resin cement on the shear bond strength and durability of zirconia ceramics.@*METHODS@#Zirconia ceramics were sintered into 20 mm×10 mm×10 mm and 10 mm×10 mm×10 mm specimens. The experiment was divided into 12 groups. The two types of specimens were bonded using two variants of resin cement (RelyX Ultimate and Clearfil SAC self-adhesive resin cement), universal adhesives (non-adhesive, Scotchbond uni-versal adhesive, and Clearfil SE One adhesive), and storage conditions (water bath and water bath-thermal cycling). The shear bond strengths were tested, and the fracture morphologies were analyzed.@*RESULTS@#The cement (F=8.41, P<0.01) and adhesive (F=30.34, P<0.01) exerted a significant effect on the shear bond strength of zirconia, whereas storage condition showed no significant effect on this property (F=1.83, P=0.18). The lowest shear bond strength (14.02 MPa±6.86 MPa) was exhibited by the group treated with RelyX Ultimate resin cement, non-adhesive, and water bath-thermal cycling, whereas the highest shear bond strength (54.12 MPa±8.37 MPa) was displayed by the group treated with RelyX Ultimate resin cement, Scotchbond universal adhesive, and water bath-thermal cycling.@*CONCLUSIONS@#Universal adhesives can improve the durability of the bonding of resin cement to zirconia. If non-self-adhesive resin cement is used without a universal adhe-sive, the durability of the bond will be greatly reduced.

Curcumin combined FOLFOX induced cell apoptosis of gastric cancer and its mechanism research / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the effect of curcumin combined folinic acid fluorouracil oxaliplatin (FOLFOX) on the gastric adenocarcinoma cell line BGC-823 and to explore its possible mechanisms.</p><p><b>METHODS</b>Cells were divided into five groups, i.e. the blank control group, the curcumin group, the FOLFOX group (0.1 mmol/L 5-FU +5 micromol/L oxaliplatin), and the curcumin combined FOLFOX group. CCK-8 was used to detect cell activity. The cell apoptosis was observed using Hoechst dyeing. Caspase-3 test kit was applied to test Caspase-3 vitality. The mRNA expressions of Bcl-2 and Bax were detected by real time fluorescent quantitative PCR. The expressions of Bcl-2 and Bax protein were determined by Western blot.</p><p><b>RESULTS</b>The BGC-823 cells' proliferation could be inhibited, apoptosis induced, the Caspase-3 activity increased, expressions of Bcl-2 mRNA and Bcl-2 protein lowered, while Bax mRNA and Bax protein expressions increased in each medicated group. Besides, the efficacy of the curcumin combined FOLFOX group was superior to that of the curcumin group and the FOLFOX group, showing statistical difference (P < 0.01).</p><p><b>CONCLUSION</b>Curcumin combined FOLFOX could significantly inhibit the proliferation of BGC-823 cells possibly via promoting Bax expression and Caspase-3 activity, inhibiting Bcl-2 expression, thus inducing apoptosis.</p>

Diagnostic value of contrast-enhanced ultrasonography in preoperative T-staging of gastric cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the diagnostic value of contrast-enhanced ultrasonography (CEUS) in preoperative T-staging of gastric cancer.</p><p><b>METHODS</b>A sulfur hexafluoride-filled microbubble ultrasound contrast agent and a continuous real-time imaging technique of contrast pulse sequencing were used. Normal gastric wall was examined by CEUS in 8 healthy volunteers and the results were compared with the findings on multislice computed tomography. Sixty-two patients with gastric cancer proved by biopsies who received preoperative CEUS examination were involved in this study, and the CEUS result was compared with postoperative pathological findings.</p><p><b>RESULTS</b>The normal gastric wall presented a one-layer structure in the portal venous phase and a three-layer structure in the arterial and equilibrium phase including a slightly hyper-enhanced inner layer, a hypo-enhanced intermediate layer, and a markedly hyper-enhanced outer layer, which corresponded histologically to the mucosal, submucosal, and muscular-serosal layer, respectively. The accuracy of transabdominal ultrasonography and CEUS in determining the T stage of gastric cancer was 72.9% and 88.1% respectively, and the difference was statistically significant (chi(2)=4.37, P=0.036).</p><p><b>CONCLUSIONS</b>CEUS shows the normal gastric wall as a one- or a three-layer structure, which provides a theory base for CEUS in preoperative T-staging of gastric cancer. CEUS is a useful diagnostic method for preoperative T-staging of gastric cancer.</p>

Comparison of preoperative T staging by oral contrast enhanced ultrasonography and double contrast enhanced ultrasonography in advanced gastric carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To compare the accuracy of preoperative T staging of gastric cancer by oral and intravenous contrast-enhanced gastric ultrasonography.</p><p><b>METHODS</b>One hundred and forty three patients who had been diagnosed as gastric cancer by endoscopic biopsy and confirmed by pathology after operation were examined by oral and intravenous contrast-enhanced gastric ultrasonography, and they were divided into satisfied group and non-satisfied group according to the 2-D image quality of lesion. The results were compared with postoperative pathologic findings.</p><p><b>RESULTS</b>All the patients with gastric cancer presented regional gastric wall thickening. Among them, 117 cases were clearly presented with good image quality. The remaining 26 cases were presented with vague profile, the ulcerative surface of lesion was filled with hyperechogenicity combined with rear shadow. The accuracy of oral contrast-enhanced ultrasonography in determining the T stage of gastric cancer was 74.1%. The accuracy in satisfied group and non-satisfied group was 78.6% and 53.8%, respectively. The enhancement pattern of 143 cases was showed as hyperenhancement during the arterial phase and hypoenhancement during the portal phase in DCUS. The accuracy of double contrast-enhanced ultrasongraphy in determining the T stage of gastric cancer was 86.7%, but the accuracy in satisfied group and non-satisfied group was 88.9% and 76.9%, respectively. There was a significant difference between the two methods (χ(2) = 9.031, P < 0.01).</p><p><b>CONCLUSION</b>DCUS is more accurate than oral contrast-enhanced ultrasonography as a useful diagnostic method for preoperative T staging of gastric cancer.</p>

Diagnostic value of double contrast-enhanced ultrasonography in preoperative staging of gastric cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the clinical value of double contrast-enhanced ultrasonography using oral and intravenous contrast agents in preoperative staging of gastric cancer.</p><p><b>METHODS</b>Sixty-two patients with biopsy-proven gastric cancer were enrolled into this study, and were examined by double contrast-enhanced gastric ultrasonography preoperatively. The results were compared with postoperative pathologic findings.</p><p><b>RESULTS</b>The accuracy of oral contrast-enhanced gastric ultrasonography and double contrast-enhanced ultrasonography in determining the T stage of gastric cancer was 72.9% (T1: 66.7%, T2: 60.0%, T3: 76.9%, T4: 71.4%) and 88.1% (T1: 66.7%, T2: 80.0%, T3: 89.7%, T4: 100%), respectively, with a statistically significant difference between the two methods (P = 0.036). The sensitivity, specificity, accuracy and Youden index of oral contrast-enhanced gastric ultrasonography and double contrast-enhanced ultrasonography in assessment of lymph node metastasis were 74.5%, 66.7%, 72.9%, and 0.41 versus 89.4%, 75.0%, 86.4%, 0.76, respectively. No significant difference in the accuracy of assessment for lymph node metastasis was observed (P > 0.05).</p><p><b>CONCLUSION</b>Double contrast-enhanced ultrasonography is useful for preoperative staging of gastric cancer, especially for T staging.</p>

Quantitative study on occlusal balance of normal occlusion in intercuspal position / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To assess occlusal balance of normal occlusion in intercuspal position with maximal bite force.</p><p><b>METHODS</b>Maximal bite force was recorded in intercuspal position by use of T-Scan II system from 123 subjects with normal intact dentitions. Occlusal balance of normal occlusion was quantitatively analyzed from center of force, percentage of bite force, and occlusal contacts.</p><p><b>RESULTS</b>The relative position of the center of bite force, the difference in bilateral force percentage, and unsymmetrical coefficient followed normal distributions. The 95% reference ranges for corresponding testing items were -6.60 to 6.68 mm, -15.50% to 12.10%, and 0.65 to 1.39. There was no statistic difference (P = 0.915) in occlusal contacts between left and right sides. The 98.4% of normal occlusion subjects had the center of bite force locating in posterior region of dentition when biting with maximal force in intercuspal position.</p><p><b>CONCLUSIONS</b>Occlusal balance could be evaluated by T-Scan II system. Occlusion of normal subjects biting with maximal force was stable and bilaterally balanced in intercuspal position.</p>