Ultrastructural study by backscattered electron imaging and elemental microanalysis of biomaterial-to-bone interface and mineral degradation of bovine xenografts in maxillary sinus floor elevation.

OBJECTIVES: The aim of this study was to perform an ultrastructural study of the bone-to-biomaterial interface and biomaterial mineral degradation in retrieved bone biopsies following maxillary sinus augmentation using bovine xenografts (Endobon(®)) in 15 clinical cases. MATERIALS AND METHODS: Nine months after sinus lifting, bone cores were harvested from the maxillary sinus. The specimens were processed for observation under a scanning electron microscope with backscattered electron imaging (SEM-BSE). In addition, chemical analysis and elemental mapping of the mineral composition were generated using a microanalytical system based on energy-dispersive X-ray spectrometry (EDX). RESULTS: No clinical complications occurred during surgery. Scanning electron microscopy revealed that newly formed bone was closely attached to the xenograft. Elemental analysis showed a significantly high Ca/P ratio in the residual biomaterials (3.031 ± 0.104) compared with the interface (2.908 ± 0.115) and new bone (2.889 ± 0.113), which suggests that there may be a gradual diffusion of Ca ions from the biomaterial into the newly forming bone at the interface as part of the biomaterial's resorption process. EDX analysis of the residual bovine biomaterial showed particle categories with different mean Ca/P ratios according to size, pointing to different stages of the resorption process. CONCLUSIONS: The biomaterial proved to be biocompatible and osteoconductive when used as a bone substitute for maxillary sinus elevation. The grafting material used is not a completely resorbable material over the time period covered by this study.

Ultrastructural study by backscattered electron imaging and elemental microanalysis of bone-to-biomaterial interface and mineral degradation of porcine xenografts used in maxillary sinus floor elevation.

OBJECTIVES: The aim of this study was to carry out an ultrastructural study of the biomaterial-to-bone interface and biomaterial mineral degradation in retrieved bone biopsies following maxillary sinus augmentation using collagenized porcine xenografts (Osteobiol(®) Mp3) in 15 clinical cases. MATERIALS AND METHODS: Nine months after sinus lifting, bone cores were harvested from the maxillary sinus. The specimens were processed for observation under a scanning electron microscope with backscattered electron imaging (SEM-BSE). In addition, chemical analysis and elemental mapping of the mineral composition were generated using a microanalytical system based on energy-dispersive X-ray spectrometry (EDX). RESULTS: No clinical complications were evident during surgery. Scanning electron microscopy revealed that newly formed bone had become closely attached to the xenograft. Statistical analysis showed a significantly high Ca/P ratio in the biomaterial (2.46 ± 0.16) and at the bone interface (2.00 ± 0.48) compared to bone (1.97 ± 0.36), which suggests that there may be a gradual diffusion of Ca ions from the biomaterial into the newly forming bone at the interface as part of the biomaterial's resorption process. EDX analysis of the residual porcine biomaterial at different points showed some particle categories with different mean ratios of Ca/P according to size, pointing to different stages of the resorption process. CONCLUSIONS: The biomaterial proved to be biocompatible, bioreabsorbable and osteoconductive when used as a bone substitute for maxillary sinus elevation. SEM-BSE revealed that newly formed bone had become closely attached to the xenografts. EDX analysis monitored the resorption process of the porcine bone xenograft. Elemental mapping showed that there was a gradual diffusion of Ca ions from the biomaterial to the newly forming bone at the interface.

Experimental model of bone response to xenografts of bovine origin (Endobon): a radiological and histomorphometric study.

OBJECTIVE: To carry out a radiological and histomorphometric evaluation of bone response to bovine bone implants inserted in rabbits' tibiae. MATERIALS AND METHODS: Twenty New Zealand rabbits weighing 3900-4500 g were used. Twenty bovine bone implants (Endobon) in granulated form of 500-1000 µm granulometry were inserted in the proximal metaphyseal area of the animals' right tibia and 20 control areas were located in the proximal metaphyseal area. Following implantation, the animals were sacrificed in four groups of five, after 1 month, 2 months, 3 months and 4 months, respectively. Anteroposterior and lateral radiographs were taken. Samples were sectioned at 5 µm and stained using Hematoxylin-Eosin and Masson's trichromic. RESULTS: After 4 months, radiological images showed complete repair of the bone defects. No healed or residual bone alterations attributable to the presence of the implant were observed. Histomorphometric analysis at 4 months showed the presence of a higher density of newly formed bone with mean values for new bone, residual graft material and non-mineralized connective tissue of 22.8 ± 1.5%, 39.4 ± 2.3% and 37.7 ± 2.5%. There were no statistically significant differences in the length of cortical formation with bovine bone, 98.8 ± 1.1%, compared with the control group, 99.1 ± 0.7%, at the end of the study period. CONCLUSIONS: The biomaterial used in the study was shown to be biocompatible, osteoconductive and non-resorbable and as such a possible bone substitute that does not interfere with normal reparative bone processes.

Bone response to hydroxyapatites with open porosity of animal origin (porcine [OsteoBiol mp3] and bovine [Endobon]): a radiological and histomorphometric study.

PURPOSE: To carry out a radiological and histomorphometric evaluation of bone response to two xenografts of animal origin, one porcine, and the other bovine, inserted in rabbits' tibiae. MATERIAL AND METHODS: Twenty New Zealand rabbits weighing 3900-4500 g were used. Twenty bovine bone grafts (Endobon) in granulated form of 500-1000 µm granulometry were inserted in the proximal metaphyseal area of the animals' right tibia, and 20 porcine bone grafts (OsteoBiol mp3) in granulated form of 600-1000 µm granulometry were inserted in the proximal metaphyseal area of the animals' left tibia. Following graft insertion, the animals were sacrificed in four groups of five, after 1, 2, 3 and 4 months, respectively. Anteroposterior and lateral radiographs were taken. Samples were processed for observation under light microscopy. Histomorphometric measurements were presented as mean values ± standard deviations. RESULTS: At 4 months after treatment, the bone defects displayed radiological images that showed complete repair of osseous defects. Histomorphometric evaluation showed that for the porcine xenograft, the study averages for newly formed bone represented 22.8 ± 1.8%, for residual graft material 23.6 ± 3% and for connective tissue 53.5 ± 2.5%, while for the bovine xenograft newly formed bone represented 23.1 ± 1.8%, residual graft material 39.4 ± 3% and non-mineralized connective tissue 37.5 ± 2.5%. CONCLUSIONS: The biomaterials assessed in the study were shown to be biocompatible and osteoconductive. Collagenized porcine xenografts proved more resorbable than bovine xenografts. Both can be used as possible bone substitutes without interfering with normal reparative bone processes.