种植支抗非拔牙矫治成人上颌前突畸形的临床研究

目的：探讨种植支抗非拔牙矫治成人上颌前突畸形的临床疗效。方法分析50例上颌前突畸形成人患者临床资料,依据支抗不同进行临床分组,对照组(传统强支抗组)20例和观察组(种植支抗非拔牙矫治组)30例。结果观察组上颌前突患者上中切牙切缘到Y轴的距离(U1-Y)、下中切牙切缘到Y轴的距离(L1-Y)、上第一磨牙冠近中点到Y轴的距离(U6-Y)、下中切牙长轴和下颌平面所形成的后上夹角(L1-MP)、上、下中切牙长轴之间的夹角(U1-L1)优于对照组,差异均有统计学意义(P<0.05)。结论不锈钢微螺钉种植系统矫治成人上颌前突畸形效果明显,值得临床推广应用。     

Repairing Defect and Preventing Collapse of Canine Femoral Head Using Titanium Implant Enhanced by Autogenous Bone Graft and rhBMP-2

There is a direct relationship between mechanical stress and the progressive collapse of the necrotic region in osteonecrosis of the femoral head. The titanium implant combined with autogenous bone graft and recombinant human bone morphogenetic protein (rhBMP)-2 to repair the defect and prevent collapse of the femoral head was investigated. The femoral head defects were made by the trapdoor procedure and then the defects were filled, respectively, with the titanium implant combined with autogenous bone graft and rhBMP-2, with autogenous bone graft and rhBMP-2, and with autogenous bone graft alone. Roentgenographic and histological examinations were performed at various times postoperatively. The defects were repaired completely and the titanium implant was integrated with the surrounding bone tissues. The defects healed faster than did without rhBMP-2. No trapdoor cartilage collapsed and joint space narrowed. The titanium implant combined with autogenous bone graft and rhBMP-2 can enhance the repairing procedure and prevent the collapse of the femoral head.     

Prophylactic Insulin Treatment of Diabetes-prone BB/OK Rats by Application of a Sustained Release Insulin Implant

Normoglycemic diabetes-prone BB/OK rats aged 33, 45 or 75 days were subjected to prophylactic insulin treatment by means of a single subcutaneous application of a sustained release insulin implant. The single application of a sustained release insulin implant decreased the incidence of diabetes or delayed the onset of the disease in BB/OK rats of all treatment groups. Prophylactic insulin administration caused a transient hypoglycemic period accompanied by an inhibition of glucose stimulated insulin secretion and a decrease of the insulin content of Langerhans' islets as detectable in vitro . Compared to islets of normoglycemic controls pancreatic islets isolated from hypoglycemic BB/OK rats within 7-21 days after the insulin application at 45 days of age displayed a decreased susceptibility of the cells to complement-dependent cytotoxicity of the monoclonal islet cell surface antibody (ICSA) K14D10 but not to the cytotoxic effect of the ICSA M3aG8. The appearance of complement-dependent antibody-mediated cytotoxicity to islet cells and pancreatic exocrine cells in serum regarded as a sign of immune dysregulation in BB/OK rats seems not to be affected by insulin prophylaxis and was detectable during hypoglycemia as well as in the subsequent normoglycemic state. In conclusion, BB/OK rats of different age can be protected from diabetes by a single application of a sustained release insulin implant. Insulin and/or hypoglycemia seem to influence the expression of cell surface antigens, thus render the islets of Langerhans less vulnerable to immune cytolysis, whereas the appearance of humoral immunological abnormalites is not affected.     

Reverse engineering techniques for cranioplasty: a case study

This paper presents rapid prototyping and reverse engineering techniques applied to create an implant for the surgical reconstruction of a large cranial defect. A series of computed tomography (CT) images was obtained and purpose built software was used to extract the cranial geometry in a point cloud. The point cloud produced was used for: (a) the creation of a stereolithographic (STL) physical model for direct assessment of the cranial defect; and (b) the creation of a 3D mould model for the fabrication of the patient-specific implant.     

Systematic review and meta-analysis of bearing dislocation in lateral meniscal bearing unicompartmental knee replacement: Domed versus flat tibial surface

BackgroundBearing dislocation is a problem following mobile bearing Oxford lateral Unicompartmental Knee Replacement (UKR). Therefore, the design of the tibial component was changed from a flat tibial surface to a domed tibial surface with a biconcave bearing to increase bearing entrapment. This systematic review compared the dislocation and revision rates of the two designs.MethodsTwo authors independently searched MEDLINE, EMBASE and ISI Web of Science, reference lists of retrieved articles, and the internet. Randomised, cohort, case-control and case studies of adult patients with lateral knee osteoarthritis treated with flat or domed Oxford lateral UKR and their outcomes were included. The overall dislocation rate and the annual revision rate (per 100 component years) were determined.ResultsNine studies (937 knees) met the inclusion criteria (3 flat, 6 domed). Four studies (all domed) had a low risk of bias and five had a high risk (3 flat, 2 domed), so data should be interpreted with caution. The bearing dislocation rate decreased from 17% (flat) to 3.7% (domed). Dislocations occurred on average at 16 months and medial dislocations were most common. The revision rate excluding dislocation decreased from 1.1%pa to 0.7%pa. PROSPERO registration: CRD42019139250.ConclusionModifying the tibial component from a flat to a domed shape decreased the bearing dislocation rate to 3.7% and increased the 10 year survival rate excluding dislocation to 93%. The dislocation rate is still relatively high so bearing stability should be assessed intra-operatively and if unacceptable, a fixed bearing version of the Oxford lateral tibial component can be inserted.     

Biofilm and cell adhesion strength on dental implant surfaces via the laser spallation technique

ObjectiveThe aims of this study are to quantify the adhesion strength differential between an oral bacterial biofilm and an osteoblast-like cell monolayer to a dental implant-simulant surface and develop a metric that quantifies the biocompatible effect of implant surfaces on bacterial and cell adhesion.MethodsHigh-amplitude short-duration stress waves generated by laser pulse absorption are used to spall bacteria and cells from titanium substrates. By carefully controlling laser fluence and calibration of laser fluence with applied stress, the adhesion difference between Streptococcus mutans biofilms and MG 63 osteoblast-like cell monolayers on smooth and rough titanium substrates is obtained. The ratio of cell adhesion strength to biofilm adhesion strength (i.e., Adhesion Index) is determined as a nondimensionalized parameter for biocompatibility assessment.ResultsAdhesion strength of 143 MPa, with a 95% C.I. (114, 176), is measured for MG 63 cells on smooth titanium and 292 MPa, with a 95% C.I. (267, 306), on roughened titanium. Adhesion strength for S. mutans on smooth titanium is 320 MPa, with a 95% C.I. (304, 333), and remained relatively constant at 332 MPa, with a 95% C.I. (324, 343), on roughened titanium. The calculated Adhesion Index for smooth titanium is 0.451, with a 95% C.I. (0.267, 0.622), which increased to 0.876, with a 95% C.I. (0.780, 0.932), on roughened titanium.SignificanceThe laser spallation technique provides a platform to examine the tradeoffs of adhesion modulators on both biofilm and cell adhesion. This tradeoff is characterized by the Adhesion Index, which is proposed to aid biocompatibility screening and could help improve implantation outcomes. The Adhesion Index is implemented to determine surface factors that promote favorable adhesion of cells greater than biofilms. Here, an Adhesion Index ? 1 suggests favorable biocompatibility.     

Persistent inhibition of Candida albicans biofilm and hyphae growth on titanium by graphene nanocoating

ObjectivesCandida albicanscolonizes biomaterial surfaces and are highly resistant to therapeutics. Graphene nanocoating on titanium compromises initial biofilm formation. However, its sustained antibiofilm potential is unknown. The objective of this study was to investigate the potential of graphene nanocoating to decrease long-term fungal biofilm development and hyphae growth on titanium.MethodsGraphene nanocoating was deposited twice (TiGD) or five times (TiGV) on grade 4 titanium with vacuum assisted technique and characterized with Raman spectroscopy and atomic force microscope. The biofilm formation and hyphae growth of C. albicans was monitored for seven days by CFU, XTT, confocal, mean cell density and scanning electronic microscopy (SEM). Uncoated titanium was the Control. All tests had three independent biological samples and were performed in independent triplicates. Data was analyzed with one- or two-way ANOVA and Tukey's HSD (α = 0.05).ResultsBoth TiGD and TiGV presented less biofilms at all times points compared with Control. The confocal and SEM images revealed few adhered cells on graphene coated samples, absence of hyphae and no features of a mature biofilm architecture. The increase in number of layers of graphene nanocoating did not improve its antibiofilm potential.SignificanceThe graphene nanocoating exerted a long-term persistent inhibitory effect on the biofilm formation on titanium. The fewer cells that were able to attach on graphene coated titanium were scattered and unable to form a mature biofilm with hyphae elements. The findings open opportunities to prevent microbial attachment and proliferation on implantable materials without the use of antibiotics.     

Mechanical behavior of nano-hybrid composite in comparison to lithium disilicate as posterior cement-retained implant-supported crowns restoring different abutments

ObjectiveResin-based materials are gaining popularity in implant dentistry due to their shock absorption capacity. Therefore, the aim of this study was to evaluate the fracture strength and failure mode of resilient materials for both crowns and abutments and compare them to the most widely used materials in different combinations after subjection to long-term fatigue loading.MethodsForty-eight cement-retained implant-restorations were assembled on titanium implants. Identical custom-made CAD/CAM abutments were milled out of 3 different materials (n = 16); T: titanium, Z: zirconia and P: ceramic-reinforced PEEK. Each group was subdivided, according to the restorative crown material, into two subgroups (n = 8); C: nano-hybrid composite and L: Lithium disilicate. Specimens were subjected to dynamic load of 98 N for 1,200,000 cycles with integrated thermal cycling. The surviving specimens were subjected to quasi-static loading until failure. Shapiro–Wilk test was used to test for normality. One-way ANOVA followed by Tukey’s post-hoc test was used to detect statistically significant differences between groups.ResultsAll specimens withstood 1,200,000 load cycles. The fracture strength values varied from a minimum of 1639 ± 205 N for group PL to a maximum of 2949 ± 478 N for group ZL.SignificanceThe abutment material influenced the fracture strength and failure mode of the restoration. A combination of zirconia abutments and nano-hybrid composite showed the most favorable mode of failure within the test groups. Therefore, this combination might be recommended as an alternative for restoring single implants in the posterior area.     

种植体掺离子表面改性技术及其促进骨结合的研究进展

种植牙因其在解决牙列缺损方面巨大的优势,已成为许多缺牙患者首选的治疗方式。在临床应用中,如何促进种植体与骨组织界面的骨结合是种植治疗成功的关键,因此种植体表面改性一直是研究的热点。骨组织中含有钙、磷、锌、镁、锶等大量微量元素,这些微量元素对于骨组织的生长发育必不可少。因此可以通过将微量元素掺入种植体表面来促进种植体骨结合。本文着重介绍了种植体表面改性的相关技术以及微量元素促进骨结合的具体机制。     

Effect of repeated use of an implant handpiece on an output torque: An in-vitro study

PURPOSEThis study aimed to evaluate the effect of repeated use of an implant handpiece under an implant placement torque (35 Ncm) and overloading torque condition (50 Ncm) on an output torque.MATERIALS AND METHODSTwo types of implant handpiece systems (Surgicpro/X-DSG20L [NSK, Kanuma, Japan] and SIP20/CRB46LN [SAESHIN, Daegu, South Korea]) were used. The output torque was measured using a digital torque gauge. The height and angle (x, y, and z axes) of the digital torque gauge and implant handpiece were adjusted through a jig for passive connection. The experiment was conducted under the setting torque value of 35 Ncm (implant placement torque) and 50 Ncm (overloading torque condition) and 30 times per set; a total of 5 sets were performed (N = 150). For statistical analysis, the difference between the groups was analyzed using the Mann-Whitney U test and the Friedman test was used to confirm the change in output torque (α=.05).RESULTSNSK and SAESHIN implant handpieces showed significant differences in output torque results at the setting torques of 35 Ncm and 50 Ncm (P<.001). The type of implant handpiece and repeated use influenced the output torque (P<.001).CONCLUSIONThere may be a difference between the setting torque and actual output torque due to repeated use, and the implant handpiece should be managed and repaired during long-term use. In addition, for successful implant results in dental clinics, the output torque of the implant handpiece system should be checked before implant placement.