Anatomic Site Evaluation of Edentulous Maxillae for Dental Implant Placement

Purpose This study evaluated 17 edentulous cadavers for bone quantity and quality of the alveolar process of the maxilla for the purpose of dental implant placement. Materials and Methods The maxillary arch was divided into four anatomically defined regions for measurements of bone quantity. Bone quality was assessed histologically and described by trabecular bone patterns and tissue composition. Results Average bone height with a minimum thickness of 4 mm was as follows: region 1, 12.1 ± 4.9 mm; region 2, 14.1 ± 7.2 mm; region 3, 6.1 ± 2.8 mm; and region 4, 8.5 ± 2.2 mm. Histological evaluation showed increased trabeculation and thicker cortex in the maxillary anterior area, regions 1 and 2. Region 3, the floor of the maxillary sinus area, had the least amount of bone; however, the quality of bone was superior to that of region 4, the maxillary tuberosity area. Trabecular distance or marrow spaces ranged from 40 μm to 2 mm with larger spaces associated with the posterior maxilla. Conclusions Maxillary tuberosity is the least desirable site for the placement of implants in the maxilla. The area corresponding to the first and second molars had the least bone thickness. All measures of bone preservation need to be considered, especially in this area.     

鹿茸多肽促进大鼠坐骨神经再生的实验研究

目的 :探讨鹿茸多肽对大鼠坐骨神经损伤后神经再生的影响。方法 :Wistar大鼠 36只 ,雌雄各半 ,随机分成对照组和鹿茸多肽用药组。建立切断大鼠坐骨神经保留一侧神经外膜模型 ,术后隔日于失神经支配的靶器官注射给药。于术后 2、4、6周观察坐骨神经功能指数、电生理、组织学及超微结构。结果 :坐骨神经功能指数、潜伏期及诱发电位恢复率在各时间点上用药组优于对照组P <0 0 1。组织学检查有髓神经纤维数、纤维直径、截面积在各时间点上用药组优于对照组P <0 0 1。超微结构观察用药组各时间点上有髓神经纤维的髓鞘厚度、成熟度均优于对照组。结论 :鹿茸多肽能促进神经再生及功能的恢复。     

益妇宁软胶囊对去卵巢大鼠骨形态和生物力学性能的影响

目的:观察益妇宁软胶囊(YFN)对去卵巢大鼠骨形态和生物力学性能的影响。方法:采用未孕产SD雌性大鼠60只,50只行双侧卵巢切除术,随机分为YFN大、中、小剂量组和阳性药对照组、模型对照组,每组10只;另10只为假手术组。术后4周开始给药,给药12周后收集标本。采用病理计量学观察骨组织形态并测量骨小梁密度,采用万能生物材料测试机测定骨生物力学指标。结果:YFN能明显增加骨小梁密度,增加股骨、椎骨最大载荷。结论:YFN能显著改善骨质疏松程度,提高骨生物力学性能。     

Osseointegration of anodized titanium implants under different current voltages: a rabbit study

The oxide layer that covers a titanium surface is extremely stable and appears to have excellent biocompatibility, which can result in successful osseointegration. The aim of this study was to analyse the characteristics of an oxide layer formed by anodic oxidation (anodization), and to evaluate the extent of bone healing around the anodized implant. The screw-type implants were made of commercially pure titanium (Grade 2). The Group 1 samples had a turned surface, and three other types of experimental specimens were anodized under constant voltages of 190 V (Group 2), 230 V (Group 3) and 270 V (Group 4). The surface characteristics of each sample type were inspected. Removal torque was measured after a 4-week healing period and the histomorphometric analysis was performed 6 weeks after implantation in rabbit tibiae. There was an increase in both the size and number of pores as the anodizing voltage increased. The Ra value of the Group 4 samples was higher than those in the Group 1 and 2 samples (P < 0.05). Group 3 showed a difference compared with Group 1 (P < 0.05). A thicker oxide layer, which contained crystalline (anatase) TiO(2) with the inclusion of some electrolytes (Ca, P), was formed at the higher anodizing voltage. Group 4 had higher removal torque values and percentages of bone-to-implant contact than the other groups (P < 0.05). The anodized titanium implants showed more intimate and stronger connections with peri-implant bone during early osseointegration than the turned titanium implants in this experimental model.     

Enhanced bone apposition around biofunctionalized sandblasted and acid-etched titanium implant surfaces. A histomorphometric study in miniature pigs

Microrough titanium (Ti) surfaces of dental implants have demonstrated more rapid and greater bone apposition when compared with machined Ti surfaces. However, further enhancement of osteoblastic activity and bone apposition by bio-functionalizing the implant surface with a monomolecular adsorbed layer of a co-polymer - i.e., poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) and its derivatives (PLL-g-PEG/PEG-peptide) - has never been investigated. The aim of the present study was to examine early bone apposition to a modified sandblasted and acid-etched (SLA) surface coated with an Arg-Gly-Asp (RGD)-peptide-modified polymer (PLL-g-PEG/PEG-RGD) in the maxillae of miniature pigs, and to compare it with the standard SLA surface. Test and control implants had the same microrough topography (SLA), but differed in their surface chemistry (polymer coatings). The following surfaces were examined histomorphometrically: (i) control - SLA without coating; (ii) (PLL-g-PEG); (iii) (PLL-g-PEG/PEG-RDG) (RDG, Arg-Asp-Gly); and (iv) (PLL-g-PEG/PEG-RGD). At 2 weeks, RGD-coated implants demonstrated significantly higher percentages of bone-to-implant contact as compared with controls (61.68% vs. 43.62%; P < 0.001). It can be concluded that the (PLL-g-PEG/PEG-RGD) coatings may promote enhanced bone apposition during the early stages of bone regeneration.     

Effects of Creatine Supplementation on Histopathological and Biochemical Parameters in the Kidney and Pancreas of Streptozotocin-Induced Diabetic Rats

Diabetes mellitus (DM) is a worldwide health concern, and projections state that cases will reach 578 million by 2030. Adjuvant therapies that can help the standard treatment and mitigate DM effects are necessary, especially those using nutritional supplements to improve glycemic control. Previous studies suggest creatine supplementation as a possible adjuvant therapy for DM, but they lack the evaluation of potential morphological parameters alterations and tissue injury caused by this compound. The present study aimed to elucidate clinical, histomorphometric, and histopathological consequences and the cellular oxidative alterations of creatine supplementation in streptozotocin (STZ)-induced type 1 DM rats. We could estimate whether the findings are due to DM or the supplementation from a factorial experimental design. Although creatine supplementation attenuated some biochemical parameters, the morphological analyses of pancreatic and renal tissues made clear that the supplementation did not improve the STZ-induced DM1 injuries. Moreover, creatine-supplemented non-diabetic animals were diagnosed with pancreatitis and showed renal tubular necrosis. Therefore, even in the absence of clinical symptoms and unaltered biochemical parameters, creatine supplementation as adjuvant therapy for DM should be carefully evaluated.