Surface pretreatments for medical application of adhesion

Abstract

Medical implants and prostheses (artificial hips, tendono- and ligament plasties) usually are multi-component systems that may be machined from one of three material classes: metals, plastics and ceramics. Typically, the body-sided bonding element is bone.The purpose of this contribution is to describe developments carried out to optimize the techniques , connecting prosthesis to bone, to be joined by an adhesive bone cement at their interface. Although bonding of organic polymers to inorganic or organic surfaces and to bone has a long history, there remains a serious obstacle in realizing long-term high-bonding strengths in the in vivo body environment of ever present high humidity.Therefore, different pretreatments, individually adapted to the actual combination of materials, are needed to assure long term adhesive strength and stability against hydrolysis. This pretreatment for metal alloys may be silica layering; for PE-plastics, a specific plasma activation; and for bone, amphiphilic layering systems such that the hydrophilic properties of bone become better adapted to the hydrophobic properties of the bone cement. Amphiphilic layering systems are related to those developed in dentistry for dentine bonding.Specific pretreatment can significantly increase bond strengths, particularly after long term immersion in water under conditions similar to those in the human body. The bond strength between bone and plastic for example can be increased by a factor approaching 50 (pealing work increasing from 30 N/m to 1500 N/m).This review article summarizes the multi-disciplined subject of adhesion and adhesives, considering the technology involved in the formation and mechanical performance of adhesives joints inside the human body.

Bonding of a Silorane‐Based Composite System to Bone

“…In general, bonding to bone is similar to dentin: (i) bone has high proportion of organic materials; (ii) blood seepage occurs from the bone; (iii) a layer of debris covers the bone after preparation. [19][20][21] The occurrence of a smear layer weakens the bonding between hard tissues and materials. Dental self-etch adhesives are widely used due to their ease of use and low technique sensitivity.…”

Partially adhesive fixation of reconstruction plates at midfacial fractures – an alternative solution to screw fixation?

“…The samples were stored for 1 to 21 days at 100 percent humidity at 37 C. Tension tests have been carried out after 1, 7, 14 and 21 days. Figure 2 presents the values of bond strength in MPa depending on the storage periods in 100 percent humidity at 37 C. In order to increase the resistance to hydrolysis of this adhesive bond between bone, bone cement and metal, the metal plates have been conditioned with silicate and silane [4]. The diagram also shows the achieved values depending on conditioning the bone with different bone bonding agents, with an additional collagen cross linking agent and without it.…”

Effects of Superimposed Micro/Nano‐Structured Titanium Alloy Surface on Cellular Behaviors In Vitro

“…The mutually perpendicular micro-grooves with the same depth of 80 mm and groove spacing of 120 mm were obtained successfully by micro-milling, which had been confirmed availability to enhance attachment with living tissue. [15,17] No macroscopic difference was discovered in surface structure comparing micro-and micro/nanostructured surfaces. A layer of porous nanonetwork with a mesh size of 50-250 nm was superimposed on the surface of micro-structure by alkali-hydrothermal reaction at a high SEM resolution (Figure 3b), in spite of little macroscopic difference discovered in surface structure (Figure 3a).…”

“…[15] The excellent properties of implants, such as proper functionality, mechanical strength, safety, biocompatibility, long-term reliability, and minimal damage to the tissue, have a significant influence on implants in clinical application. [16,17] With the development of mechanical attachment techniques, the reliability of implants can be improved by micro-manufacturing technique, such as micro-milling. The feasibility of fabricating microbarbs array on polymethyl methacrylate using two kinds of micro-scale milling tools had been confirmed and implants with arrays of microbarbs may be steadier, which could facilitate microsurgical procedures.…”