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Comparison of durability of resorbable polymer pins in in vitro and in vivo conditions: preliminary study

Stodolak-Zych E., Pałka K., Szponder T., Nowicka K., Błażewicz S.

Engineering of Biomaterials

2014

Vol. 17, no. 128-129

87--89

The work focuses on polymeric cartilage/bone pins (pegs) that were manufactured and tested to assess their application in meniscus injuries. The bone pins measuring 1,2 and 4 mm in diameter were produced from certified resorbable PLDLA by means of hot pressing (at 126oC). In order to establish the material characteristics, tests of mechanical properties, structural testing and stability tests were performed in vitro (an immersion medium: water/PBS buffer). It was established that after three months of incubation the initial implant’s bending strength (120 MPa) decreased by 35%, whereas its tensile strength (52 Pa) weakened by 60%. The degree of degradation did not affect the pH of the immersion fluid. The observed physical changes of the implant, such as: the mass decrease, the change of shape, the increase of crystallinity (DSC/TG), the number of polymer terminal groups (-OH, -COOH), proved the advanced degradation process of PLDLA pins. Implants of particular behaviour were inoculated into the tibia of a New Zealand rabbit. In vivo tests were conducted to confirm the changes observed in vitro. Monitoring of the degradation process was performed after three months following the implantation by means of control X-ray and computed microtomography (μCT).

Radiocarbon dating of the Bronze Age bone pins from Eurasian Steppe

Shishlina N. I., Plicht J. van der, Zazovskaya E. P.

Geochronometria

2011

Vol. 38, no. 2

107-115

Bone catapult and hammer-headed pins played one of very specific roles in funerary offer-ings in the Bronze Age graves uncovered in the Eurasian Steppes and the North Caucasus. Scholars used different types of pins as key grave offerings for numerous chronological models. For the first time eight pins have been radiocarbon dated. 14C dating of bone pins identified the catapult type pin as the earliest one. They marked the period of the Yamnaya culture formation. Then Yamnaya popu-lation produced hammer-headed pins which became very popular in other cultural environments and spread very quickly across the Steppe and the Caucasus during 2900-2650 cal BC. But according to radiocarbon dating bone pins almost disappeared after 2600 cal BC.