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Surface pretreatments for medical application of adhesion.

Erli HJ, Marx R, Paar O, Niethard FU, Weber M, Wirtz DC - Biomed Eng Online (2003)

Bottom Line: 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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Prosthetic Dentistry, Section of Dental Materials, University Hospital of the University of Technology, Aachen, Germany. herli@ukaachen.de

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.

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Retention of PVDF tendon and fixation element. Pulling at fixation element (banjo bolt) and PVDF tendon until break. Diameter of tendon 2,5 mm. Tendon with tight network. Prosthesis 24 hours soaked in boiling physiological salt solution at 100°C before being tested.
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Figure 14: Retention of PVDF tendon and fixation element. Pulling at fixation element (banjo bolt) and PVDF tendon until break. Diameter of tendon 2,5 mm. Tendon with tight network. Prosthesis 24 hours soaked in boiling physiological salt solution at 100°C before being tested.

Mentions: From in vitro experiments we have learned (Fig. 14) that the presently proposed implant allows a retention force (measured by axially pulling on ends of fixation element and tendon simultaneously) of at least 350 N. This force is sufficient to keep the implant stable under body conditions for at least several months, allowing the body to heal the tendon by scar-formation and adapting it to the load capability required for individual patient activities. These adhesively fixed tendons have the advantage of a very smooth power flow between the PVDF tendon and the screw, much smoother than attainable by clamps. Moreover, a particularly space saving kind of attachment is at hand. Note that it is possible to machine specifically adapted screws that allow fixation of the PVDF tendon under different angles between the axis of the screw and the tendon. Because of the smooth power flow from the tendon into the screw, the risk of injuring and weakening the tendon by notch effects, as they are typical for clamps, is much lower.


Surface pretreatments for medical application of adhesion.

Erli HJ, Marx R, Paar O, Niethard FU, Weber M, Wirtz DC - Biomed Eng Online (2003)

Retention of PVDF tendon and fixation element. Pulling at fixation element (banjo bolt) and PVDF tendon until break. Diameter of tendon 2,5 mm. Tendon with tight network. Prosthesis 24 hours soaked in boiling physiological salt solution at 100°C before being tested.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC222922&req=5

Figure 14: Retention of PVDF tendon and fixation element. Pulling at fixation element (banjo bolt) and PVDF tendon until break. Diameter of tendon 2,5 mm. Tendon with tight network. Prosthesis 24 hours soaked in boiling physiological salt solution at 100°C before being tested.
Mentions: From in vitro experiments we have learned (Fig. 14) that the presently proposed implant allows a retention force (measured by axially pulling on ends of fixation element and tendon simultaneously) of at least 350 N. This force is sufficient to keep the implant stable under body conditions for at least several months, allowing the body to heal the tendon by scar-formation and adapting it to the load capability required for individual patient activities. These adhesively fixed tendons have the advantage of a very smooth power flow between the PVDF tendon and the screw, much smoother than attainable by clamps. Moreover, a particularly space saving kind of attachment is at hand. Note that it is possible to machine specifically adapted screws that allow fixation of the PVDF tendon under different angles between the axis of the screw and the tendon. Because of the smooth power flow from the tendon into the screw, the risk of injuring and weakening the tendon by notch effects, as they are typical for clamps, is much lower.

Bottom Line: 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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Prosthetic Dentistry, Section of Dental Materials, University Hospital of the University of Technology, Aachen, Germany. herli@ukaachen.de

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.

Show MeSH
Related in: MedlinePlus