共查询到20条相似文献,搜索用时 31 毫秒
1.
目的:探讨不同纤维桩表面处理方式对牙根修复后抗折裂强度的影响。方法:收集行正畸拔除的前磨牙120颗作为本研究样本,随机将120个纤维桩分为对照组、喷砂组和过氧化氢酸蚀组,每组40例。对照组纤维桩表明不给予任何处理,喷砂组给予氧化铝砂粒持续喷砂粗化处理,过氧化氢酸蚀组给予10%过氧化氢溶液处理,均包埋于纤维桩道预备好的离体牙内,采用相同树脂制备成核,行全冠修复与黏固,再模拟口腔内部环境给予样本牙冷热循环处理,经相同环境加载后,置于电子万能实验机获取样本牙抗折裂强度数据。对比三组离体牙样本体型数据、离体牙断裂方式、抗折裂强度,对三组进行为期24个月的定期随访,统计三组修复体断裂率,并采用Kaplan-Meier曲线和Log Rank法分析三组的生存状况。结果:三组的离体牙样本关于牙齿长度、牙根长度、颈部颊舌径及颈部近远中径对比差异无统计学意义(P0.05);喷砂组和过氧化氢酸蚀组的离体牙抗折裂强度显著强于对照组(P0.05);喷砂组和过氧化氢酸蚀组的牙齿折裂总发生率分别为20.00%和22.50%,均显著低于对照组的70.00%(P0.05)。但两组间比较差异无统计学意义(P0.05)。喷砂组、过氧化氢酸蚀组的生存状况显著优于对照组。结论:前磨牙修复过程中,对纤维桩表面进行喷砂或过氧化氢酸蚀处理均能提高牙根修复后抗折裂强度,改善修复体修复效果生存状况,且两种纤维桩表面处理方式对离体牙样本的断裂方式和抗折裂强度影响相当。 相似文献
2.
目的:观察成品螺纹桩、铸造钴铬合金桩核、纤维桩修复残根残冠的临床应用效果.方法:将90例患者90颗残根残冠,随机分成3组,分别采用A组成品螺纹桩,B组铸造钴铬合金桩核,C组纤维桩进行修复,并随诊18个月后,比较3组患者治疗后的成功率.结果:3组患者经过治疗后,成品螺纹桩组的成功率为73.33%,铸造钴铬合金桩核组的成功率为60.00%,纤维桩组的成功率为96.67%,三组差异有统计学意义(P<0.005).结论:与成品螺纹桩和铸造钴铬合金桩核相比,纤维桩具有更好的粘结性及抗折能力. 相似文献
3.
Teeth with crown structure less than 50% can be restored. Therefore, it is of interest to evaluate an in vitro efficacy of Zirconia post, Glass fiber post, polyethylene-woven fiber posts, and Quartz posts. Forty eight recently extracted mandibular first premolar teeth were randomly grouped in to 4 different groups with 12 samples in each group. After endodontic treatment samples in all groups underwent post preparation followed by restoration with respective posts. The mean fracture resistance (Newton) were 463.5 ± 14.3 (Group I) 425.2± 23.5 (group II), 410.4± 18.6 (Group 3) and 385.2 ± 14.2 (group 4). Data shows that Zirconia post had highest fracture resistance compared to other tested groups. 相似文献
4.
目的:探讨金属桩与玻璃纤维桩对老年上颌前牙残根残冠修复的临床疗效。方法:收集我院口腔科收治的上颌前牙残根残冠修复患者40例,随机分为玻璃纤维桩组和金属桩组,每组各20例,玻璃纤维桩组患者给予玻璃纤维桩进行残根残冠修复,金属桩组给予金属桩进行残根残冠修复,治疗结束后1年随访,对所有患者的牙龈指数(GI)、修复齿出血指数(SBI)、不良反应发生率、患者修复效果以及患者疗效进行检测并比较。结果:与治疗前相比,两组患者的牙龈指数(GI)以及修复齿出血指数(SBI)均下降(P0.05);与金属桩组相比,玻璃纤维桩组患者的牙龈指数(GI)以及修复齿出血指数(SBI)较低(P0.05),不良反应发生率较低(P0.05),颜色匹配率以及边缘适合率较高(P0.05),两组患者修复体完整例数百分率比较无明显差异(P0.05),玻璃纤维桩组患者的治疗成功率较高(P0.05)。结论:玻璃纤维桩在老年上颌前牙残根残冠修复的应用与金属桩组相比临床效果较好。 相似文献
5.
目的:探讨老年残根残冠应用纤维桩树脂核修复的临床效果及对病人生活质量的影响。方法:抽选我院行纤维桩树脂核修复的79例(86颗)老年残根残冠患者,对其进行3年随访,观察总体及不同牙位修复成功率和修复前、后生活质量的变化。结果:修复后进行3年随访,86颗残根残冠修复总成功率为95.3%,不同牙位修复成功率无显著差异(P0.05),均在94%以上,86颗牙失败4颗(其中2颗并发牙周炎、2颗牙纤维桩脱落,均未出现牙桩折断);修复后患者生活质量总分及各维度评分均明显优于修复前(P0.05)。结论:纤维桩树脂核是一种极为理想的残冠残根修复材料,能显著提高老年患者术后的生活质量,值得临床推广。 相似文献
6.
摘要 目的:探讨纤维桩、纳米复合树脂结合氧化锆烤瓷冠对根管治疗后后牙楔状缺损患者美学效果及牙周组织的影响。 方法:选取2018年1月至2019年3月期间我院收治的103例患者作为研究对象,按修复材料的不同分为对照组(n=52,患牙62颗)和研究组(n=51,患牙63颗)。对照组给予金属桩核、金属烤瓷冠修复,研究组给予纤维桩、纳米复合树脂结合氧化锆烤瓷冠修复。修复1年后,评价两组的修复成功率和修复效果。比较两组修复前及修复后1年的牙龈指数、菌斑指数、牙周探诊深度、龈沟液量及龈沟液中碱性磷酸酶(ALP)、天门冬氨酸转氨酶(AST)水平。 结果:研究组的修复成功率比对照组高(P<0.05)。研究组修复体的表面光滑率、边缘密合性、固定良好率及颜色匹配率均明显高于对照组(P<0.05)。两组治疗后牙龈指数、菌斑指数及牙周探诊深度均明显低于治疗前(P<0.05),龈沟液量及龈沟液中ALP、AST水平均明显低于治疗前(P<0.05),同时研究组治疗后牙龈指数、菌斑指数及牙周探诊深度均低于对照组(P<0.05),但两组治疗后龈沟液量及龈沟液中ALP、AST水平比较无差异(P>0.05)。 结论:纤维桩、纳米复合树脂结合氧化锆烤瓷冠对根管治疗后后牙楔状缺损的修复成功率高,修复后美学效果佳,对牙周组织影响小。 相似文献
7.
目的:对比玻璃纤维桩树脂核与铸造金属桩核修复上颌前牙残根残冠的疗效。方法:选取2011年10月至2013年12月在我院口腔科就诊的120例因前牙牙体缺损或者冠折需行桩核冠修复术的患者,随机分为玻璃纤维桩组及铸造金属桩组,每组各60例。玻璃纤维桩组采取玻璃纤维桩核与烤瓷全冠修复术治疗,铸造金属桩组采取钴铬合金铸造桩核与烤瓷全冠修复术治疗。对比2组患者修复治疗的疗效及失败情况。结果:玻璃纤维桩组有1例(1颗)患者因搬迁失访,铸造金属桩组有2例(2颗)患者因金属致敏性导致治疗中断;余117例(179颗)患者中,玻璃纤维桩组共92颗牙,成功率为89.13%,铸造金属桩组共87颗牙,成功率为79.31%,玻璃纤维桩组的明显高于铸造金属桩组;玻璃纤维桩组牙根折裂、桩核松动或脱落的发生率明显低于铸造金属桩组;而桩核折的发生率则明显高于铸造金属桩组,差异有统计学意义(P0.05)。结论:玻璃纤维桩具有美观、抗疲劳、易于操作、患者复诊次数少等优势,且不存在细胞毒性及过敏反应等问题,其修复效果优于铸造金属桩核。 相似文献
8.
ObjectiveMolar intrusion by mini-screw implantation can cause different degrees of root resorption. However, most methods (2-D and 3-D) used for evaluating root resorption have focused on the root length without considering 3-D resorption. The purpose of this study was to volumetrically evaluate root resorption using cone beam computed tomography(CBCT) after mini-screw implant intrusion. Materials and Methods1. The volumes of 32 teeth were measured using CBCT and laser scanning to verify the accuracy of CBCT. 2. Twelve overerupted molars from adult patients were investigated in this study. After mini-screw implants were inserted into the buccal and palatal alveolar bones, 150 g of force was applied to the mini-screw implants on each side to intrude the molars. CBCT images of all patients were taken immediately prior to intrusion and after intrusion. The volumes of the roots were calculated using the Mimics software program. The differences between the pre-intrusion and post-intrusion root volumes were statistically evaluated with a paired-samples t-test. In addition, the losses of the roots were statistically compared with each other using one-way analysis of variance at the P<0.05 level. ResultsNo statistically significant volume differences were observed between the physical (laser scanning) and CBCT measurements ( P>0.05). The overerupted molars were significantly intruded ( P<0.05), and the average intrusion was 3.30±1.60 mm. The differences between the pre-intrusion and post-intrusion root volumes were statistically significant for all of the roots investigated ( P<0.05). The roots were sorted by volume loss in descending order as follows: mesiobuccal, palatal, and distobuccal. Statistical significance was achieved among the three roots. The average total resorption for each tooth was 58.39±1.54 mm 3. ConclusionVolume measurement using CBCT was able to effectively evaluate root resorption caused by mini-screw intrusion. The highest volume loss was observed in the mesiobuccal root among the three roots of the investigated first molar teeth. 相似文献
9.
The flagellar pocket (FP) is the only endo- and exocytic organelle in most trypanosomes and, as such, is essential throughout the life cycle of the parasite. The neck of the FP is maintained enclosed around the flagellum via the flagellar pocket collar (FPC). The FPC is a macromolecular cytoskeletal structure and is essential for the formation of the FP and cytokinesis. FPC biogenesis and structure are poorly understood, mainly due to the lack of information on FPC composition. To date, only two FPC proteins, BILBO1 and FPC4, have been characterized. BILBO1 forms a molecular skeleton upon which other FPC proteins can, theoretically, dock onto. We previously identified FPC4 as the first BILBO1 interacting partner and demonstrated that its C-terminal domain interacts with the BILBO1 N-terminal domain (NTD). Here, we report by yeast two-hybrid, bioinformatics, functional and structural studies the characterization of a new FPC component and BILBO1 partner protein, BILBO2 (Tb927.6.3240). Further, we demonstrate that BILBO1 and BILBO2 share a homologous NTD and that both domains interact with FPC4. We have determined a 1.9 Å resolution crystal structure of the BILBO2 NTD in complex with the FPC4 BILBO1-binding domain. Together with mutational analyses, our studies reveal key residues for the function of the BILBO2 NTD and its interaction with FPC4 and evidenced a tripartite interaction between BILBO1, BILBO2, and FPC4. Our work sheds light on the first atomic structure of an FPC protein complex and represents a significant step in deciphering the FPC function in Trypanosoma brucei and other pathogenic kinetoplastids. 相似文献
10.
The post-partum reproductive performance of suckled and non-suckled Afrikaner cows was compared in order to assess the importance of suckling in the resumption of post-partum ovarian function in this breed. Non-suckled cows were weaned at 3 days post partum whilst calves in the control group had continuous access to their dams. Commencement of ovarian activity was significantly ( P < 0.01) earlier in non-suckled cows at 18.1 ± 5.2 (mean ± SD) days post partum than in suckled cows 53.2 ± 19.7 days. Conception rates were significantly higher ( P = 0.01) in non-suckled cows (80%) than in suckled cows (50%). Mean intervals from parturition to conception were 45.8 ± 15.8 (mean ± SD) days in non-suckled cows as compared with 70.9 ± 17.9 days in suckled cows. The conception rate associated with each ovulation appears to be highest between 50 and 70 days post partum regardless of the degree of suckling stimulus. Four classes of ovarian activity were recorded from the progesterone profiles compiled. The incidence of short cycles was unaffected by the degree of suckling stimulus. Weaning may ( P = 0.05) reduce the proportion of cows which exhibit regular cyclic ovarian activity without conceiving. Coitus during oestrus may (0.01 < P > 0.05) be more easily observed in non-suckled cows than in their suckled contemporaries. Suckling altered the diurnal distribution of coitus, with non-suckled cows showing the highest frequency for this component of oestrus before 09.00 h and after 15.00 h, whilst in suckled cows coitus appeared to be more evenly distributed throughout the day. 相似文献
11.
Patients with diabetes mellitus (DM) have various skeletal disorders and bone quality can be impaired in DM leading to fractures. Wistar albino male rats (270?C300?g; n?=?16) were assigned randomly to nondiabetic and diabetic rats (single dose intravenous injection of 45?mg/kg streptozotocin). All rats in each group were perpetuated for 8?weeks, and blood glucose levels as well as body weights were measured once weekly. Biomechanical measurements were performed at the mid-diaphysis of the left femur with tensile test. Extrinsic and intrinsic properties were measured or calculated. Bone mineral density (BMD) was also evaluated and measured by dual-energy X-ray absorptiometry. Cross-sectional area of the femoral shaft was evaluated by computerized tomography. Blood glucose levels in diabetic rats were significantly increased compared to that of the nondiabetic rats, while the body and femur weights were decreased ( P?<?0.05). In respect to the BMD, cross-sectional area and femur length, there were no statistically significant differences between the nondiabetic and diabetic rats ( P?>?0.05). The maximum load, ultimate stress, and toughness endpoints in diabetic rats were significantly decreased compared to that of the nondiabetics ( P?<?0.05). There were no statistically significant differences between the nondiabetic and diabetic rats with regard to the displacement and stiffness ( P?>?0.05). Femurs of diabetic rats had less absorbed energy than that in nondiabetics ( P?<?0.05). Ultimate strain was lower in diabetic rats than that in nondiabetics, while the elastic modulus was higher ( P?>?0.05). The bone quality of rats is decreased by streptozotocin-induced type 2 diabetes mellitus. 相似文献
12.
This paper investigated the mechanical behavior of a new customized post system built up with a composite framework presently utilized for crowns, bridges, veneers and inlay/onlay dental restorations. The material has been shaped so to follow perfectly the profile of the root canal in order to take advantage of the better mechanical properties of composites with respect to metallic alloys commonly used for cast posts. The analysis has been carried out with 3D finite element models previously validated on the basis of experimental work. The new post system has been compared to a variety of restorations using either prefabricated or cast posts. The structural efficiency of the new restoration has been evaluated for an upper incisor under different loading conditions (mastication, bruxism, impact). Results prove that maximum stress values in restored teeth are rather insensitive to post types and materials. However, the new customized composite restoration allows to reduce significantly the stresses inside the dentinal regions where conservative clinical interventions are not possible. 相似文献
13.
The objective of this study was to investigate the effect of time of first postpartum ovulation after calving on uterine involution in dairy cows with and without uterine puerperal disease. Transvaginal follicular puncture (FP) of follicles >6 mm suppressed ovulation and development of a CL until Day 42 after calving. Fifty-three lactating Holstein Friesian cows (3.4 ± 1.2 years old, parity 2.5 ± 1.0 [median ± mean absolute deviation]) were divided into groups on the basis of the presence (UD+) or absence (UD−) of uterine disease and whether FP was carried out (FP+) or not (FP−). Uterine disease was defined as the occurrence of retained fetal membranes and/or metritis. This resulted in the following groups: UD−FP− ( n = 15), UD−FP+ ( n = 13), UD+FP− ( n = 13), and UD+FP+ ( n = 12). A general examination, vaginoscopy, transrectal palpation, and transrectal B-mode sonography of the reproductive organs were conducted on Days 8, 11, 18, and 25 and then every 10 days until Day 65 after calving. After hormonal synchronization of ovulation (cloprostenol between Days 55 and 60 postpartum and GnRH 2 days later), cows were inseminated in the next spontaneous estrus. On average, the cows ovulated on Day 21.0 ± 6.0 (UD−FP−), 50.0 ± 4.0 (UD−FP+), 16.0 ± 3.0 (UD+FP−), and 48.0 ± 2.0 (UD+FP+) postpartum. Calving-to-conception interval and first-service conception rates were not affected by FP (P > 0.05). Healthy cows with FP had smaller (P < 0.05) uterine horn and cervical diameters assessed sonographically than cows without FP. FP reduced the prevalence of purulent vaginal discharge and uterine size assessed transrectally in UD+ cows (P < 0.05). The results showed that suppression of an early ovulation by transvaginal FP improved uterine involution in cows with and without uterine disease. 相似文献
14.
摘要 目的:对比不同治疗方法对中青年残根残冠患者咀嚼功能及舒适度的影响。 方法:2018年8月到2020年7月选择在本院进行前牙美容修复的中青年残根残冠患者82例,根据随机信封抽签原则将患者分为观察组40例与对照组42例。对照组给予牙冠延长术治疗,观察组给予纤维桩加全瓷冠修复治疗,记录与随访患者预后情况。 结果:两组修复后3个月的舌向集中??侧向??与前伸??最大应力值小于解剖??(P<0.05),解剖??的正中??少于侧向??与前伸??(P<0.05),组间对比差异无统计学意义(P>0.05)。观察组修复后3个月的咬合接触时间多于对照组(P<0.05),左右侧??力百分比、??力中心距离少于对照组(P<0.05)。观察组修复后3个月的成功率为97.5 %,高于对照组的85.7吧%(P<0.05)。观察组修复后3个月的外观效果与舒适水平评分均高于对照组(P<0.05)。随访12个月,观察组的牙龈萎缩、感染、松动等并发症发生率为2.5 %,低于对照组的19.0 %(P<0.05)。 结论:相对于牙冠延长术,纤维桩加全瓷冠在前牙残根残冠修复中的应用能提高患者的咀嚼功能与舒适度,并不会影响光弹性状况,从而提高修复效果,减少随访并发症的发生。 相似文献
15.
We prospectively studied the effectiveness of the repositioning suture of the erector spinae muscle for lumbar spine surgery using the posterior approach. 393 patients undergoing lumbar spine surgery were randomized to receive the repositioning or conventional suture of the erector spinae muscle. Time to stitch removal and drainage volume was recorded at 24 and 48 h after operation. Hemoglobin loss rate was determined at 48 h post operation and the rate of malunion (redness, swelling and effusion at stitch removal and would disruption after stitch removal) was recorded. Low back pain was evaluated using the visual analog scale (VAS) preoperatively and 6 and 12 months after operation. Time to stitch removal was comparable in lumbar spine surgery patients receiving the repositioning or conventional suture of the erector spinae muscle ( P > 0.05). Compared with the conventional suture, the repositioning suture was associated with significantly reduced drainage volume both at 24 ( P < 0.01) and 48 h after operation ( P < 0.05). Hemoglobin loss rate at 48 h post operation was also markedly lower in lumbar spine surgery patients receiving the repositioning suture than in those receiving the conventional suture ( P < 0.01 or 0.05). Furthermore, the malunion rate in lumbar spine surgery patients using the repositioning suture was markedly lower than that in the conventional group ( P < 0.05 or 0.001). There was no difference in preoperative VAS scores in both the groups ( P > 0.05). Compared with the conventional suture, the repositioning suture was associated with significantly reduced VAS scores both at 24 and 48 h after operation ( P < 0.01 in both). The repositioning suture of the erector spinae muscle is superior to the conventional suture in posterior lumbar spine surgery with marked lessened pain and reduced drainage volume. 相似文献
16.
The results of 22 absolute left ventricular volume (LVV) determinations by a radionuclide (RN) method are compared to the results obtained by contrast ventriculography (CV). Another 10 patients were analysed in order to evaluate the interstudy, interobserver and intraobserver variances. Good correlation was shown between the RN and CV measurements of the end diastolic volume (EDV), end systolic volume (ESV), stroke volume (SV) and ejection fraction (EF), but the RN method overestimates the EDV and ESV. The EF was underestimated, but no difference could be shown for the SV. On the inter- and intraobserver levels, regression analysis yielded excellent correlation ( r > 0.99 in all cases) with no statistically significant difference ( P < 0.05). The interstudy variance was minimal as indicated by regression analysis ( r > 0.87) and no statistically significant difference ( P < 0.05) could be shown between studies. The results indicate that the RN method of LVV determination can be used in intervention studies over a limited period. 相似文献
17.
A study was conducted using 240 female day-old broiler chicks to evaluate the effects of dietary chromium picolinate (CrPic), peppermint essential oil (P.mint), or their combination on growth performance and blood biochemical parameters of female broiler chicks raised under heat stress conditions (HS, 23.9 to 38 °C cycling). Average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were obtained from 1 to 42 days of age. Furthermore, at the end of the experiment (day 42), birds were bled to determine some blood biochemical parameters and weighed for final body weight (BW). ADFI, ADG, and BW were not influenced significantly by dietary CrPic and P.mint ( P?>?0.05). A significant interaction between dietary CrPic and P.mint on FCR ( P?=?0.012) was detected. FCR significantly decreased in chicks fed the diet including both CrPic and P.mint compared with the CrPic group. Significant interaction between dietary P.mint and CrPic on serum concentrations of triglycerides, glucose, and albumin were observed ( P?<?0.05), but the other measured blood biochemical parameters were not statistically affected by dietary treatments ( P?>?0.05). The serum concentrations of glucose, triglycerides were decreased ( P?<?0.05) in broilers fed the diet including both CrPic and P.mint. Plasma chromium (Cr) content increased significantly ( P?<?0.05) in birds fed the CrPic-included diet compared with the control group ( P?<?0.05). From the results of the present experiment it can be concluded that dietary supplementation with combined P.mint and CrPic could have beneficial effects on some blood biochemical parameters of female chicks reared under heat stress conditions. 相似文献
18.
The study was conducted to investigate the effects of dietary n-3 highly unsaturated fatty acid (n-3 HUFA) on growth, nonspecific immunity, expression of some immune related genes and disease resistance of juvenile large yellow croaker ( Larmichthys crocea) following natural infestation of parasites ( Cryptocaryon irritans). Six isoproteic and isolipidic diets were formulated with graded levels of n-3 HUFA ranging from 0.15% to 2.25% of the dry weight and the DHA/EPA was approximately fixed at 2.0. Each diet was randomly allocated to triplicate groups of fish in floating sea cages (1.0 × 1.0 × 1.5 m), and each cage was stocked with 60 fish (initial average weight 9.79 ± 0.6 g). Fish were fed twice daily (05:00 and 17:00) to apparent satiation for 58 days. Results showed that moderate n-3 HUFA level (0.98%) significantly enhanced growth compared with the control group (0.15% HUFA) ( P < 0.05), while higher n-3 HUFA levels (1.37%, 1.79% and 2.25%) had detrimental effects on the growth though no significance was found ( P > 0.05). Nitro blue tetrazolium (NBT) positive leucocytes percentage of head kidney and serum superoxide dismutase (SOD) activity increased with increasing n-3 HUFA from 0.15% to 0.60%, and decreased with further increase of n-3 HUFA from 0.60% to 2.25% ( P < 0.05). Serum lysozyme activity increased significantly as n-3 HUFA increased from 0.15% to 1.37%, and then decreased with n-3 HUFA from 1.37% to 2.25% ( P > 0.05). There were no significant differences in phagocytosis index (PI) of head kidney leucocytes among dietary treatments ( P > 0.05). The hepatic mRNA expression of Toll-like receptor 22 (TLR22) and Myeloid differentiation factor 88 (MyD88) was significantly up-regulated in fish fed the diets with low or moderate levels, while in kidney this increment was only found at specific sampling time during the natural infestation of parasites. The 13 d cumulative mortality rate following natural infestation of parasites decreased with n-3 HUFA increased from 0.15% to 0.60% ( P < 0.05), and significantly increased with n-3 HUFA from 0.60% to 2.25% ( P < 0.05). Results of this study suggested that fish fed low or moderate dietary n-3 HUFA had higher growth, nonspecific immune responses, expression levels of some immune related genes and disease resistance of large yellow croaker following natural infestation of parasites and dietary n-3 HUFA may regulate fish immunity and disease resistance by altering the mRNA expression levels of TLR22 and MyD88. 相似文献
19.
Whole (WSB) or ground (GSB) full-fat soybeans were extruded at 80, 100, 120 or 140°C and incorporated into broiler diets at 30% inclusion level during a 3-week trial.Extrusion of soybeans at 140 °C improved feed intake compared to those extruded at lower temperatures ( P < 0.05). However, there were no significant effects of the extrusion temperature on weight gain, feed:gain ratio or mortality rate ( P > 0.05). Also, there were no significant effects of whether the extrusion was undertaken prior to or after grinding of the soybeans on feed intake, weight gain, feed:gain ratio, or mortality rate ( P > 0.05). There was no significant interaction between the extrusion temperature and the form extruded on any of the performance parameters ( P > 0.05).Although increase in extrusion temperature reduced the trypsin inhibitor activity (TIA) of the soybeans, there were no significant effects of the extrusion temperature or type of soybean extruded on nitrogen, fat, calcium or phosphorus retention or diet ME ( P > 0.05).It is concluded that low temperature extrusion of full fat soybeans does not reduce TIA to a satisfactory level (< 10 mg g −1 sample) that will enable high dietary inclusion of such extruded soybeans for broilers. 相似文献
20.
The design of a post and core restoration is a trade-off between a series of requirements to achieve stability of the post itself, the surrounding root dentine and the joint between tooth and post, while maintaining a sufficient apical seal of the remaining root canal filling. Post and core restoration systems come in a variety of different designs and dimensions, where each has its specific strength and weakness. With the exception of threaded versions, posts normally rely on either chemical and/or frictional locking between the post and the remaining root. Failure due to fatigue of the joint or root fracture due to overloading of the dentine is a frequent failure mode, especially for posts anchoring removable prostheses. Perforation of the root in an attempt to maximize the post length is a main cause for failure, too. A new design is proposed which uses a short but large diameter post. The risk of decementation is reduced by positive locking. A cavity with an undercut is prepared into the root, into which the post is fitted. Once joined, the post cannot be separated from the tooth without destruction of either the root or the post. The principle of the new design uses preparation tools and a post which is spread at the bottom. A cylindrically prepared hole is re-shaped to a defined inverse taper with the wider diameter at the bottom of the hole. A cylindrical post is inserted and spread at the bottom to a matching shape after placement. A first in vitro test of the stability showed that the positive locking provides at least as good extraction resistance as conventional post without the critical reliance on the luting/bonding agent. 相似文献
|