Biomedical subjects

P Alberius

Publications and source records attributed to P Alberius.

62 records · Page 4Linked to original sources

PubMed1983

Pattern of membranous and chondral bone growth. A roentgen stereophotogrammetric analysis in the rabbit.

To elucidate longitudinal tubular bone growth patterns in relation to craniofacial development, nine 4-week-old male New Zealand white rabbits received tantalum implants in the calvarial bones and in the proximal and distal tibial epiphyses. The animals were examined by roentgen stereophotogrammetry. The rapid growth rate deceleration pertained to all growth regions studied, except the sagittal suture. A brief period of under-nutrition highlighted the parallel in growth rates between the frontonasal suture (associated to the facial skeleton) and the tibia. The neurocranial coronal suture exhibited a different growth pattern, presumably related to neural tissue expansion, which was also observed to rapidly react to nutritional deficiency. Tibial growth was found to sensitively reveal influences of somatic development. Hence, it might be used to optimize growth evaluations.

Animals↗

PubMed1983

Roentgen stereophotogrammetric analysis of growth at cranial value sutures in the rabbit.

Biometric characterization of rabbit cranial vault bone separation was attempted to further elucidate sutural growth mechanisms. The internasal and frontonasal sutures, connected to the facial skeleton, were also investigated. 17 male New Zealand white rabbits were studied from age 4 to 21 weeks using roentgen stereophotogrammetry with tantalum implants. A uniform cranial growth pattern with successively decreasing rates was observed, as were different growth rates at the neurocranial bones relative to those of the facial skeleton. Anteroposterior length increase was due mainly to bone separation at the frontonasal suture. Growth at the sagittal suture was minimal. Minor rate fluctuations and compensatory rebounds after periods of reduced growth were continuously observable. Small left-right differences within each individual were registered. Oscillations in growth rate across adjacent sutural areas and occasional negative growth values imply that bone separation at sutures demonstrates an alternating pattern of translations and rotations. The experimental data demonstrated the plasticity and variability of normal cranial vault growth.

Animals↗

PubMed1983

A roentgen stereophotogrammetric system. Construction, calibration and technical accuracy.

The principles for a system of roentgen stereophotogrammetric analysis for experimental and clinical applications are presented. Only the positions of implanted reference markers in the investigated object are measured. Tantalum balls, 0.5 or 0.8 mm in diameter, are used as reference markers. Standard roentgen equipment, permitting simultaneous exposure from two roentgen tubes, is employed. The calibration equipment, a glass calibration cage containing radiopaque markers, introduces a rectangular laboratory coordinate system in the roentgen investigation. The calibration of the calibration equipment itself and the obtained methodologic accuracy in determining distances, volumes and movement parameters is described for various film/screen and marker combinations.

Animals↗

PubMedDate not supplied

Comparison of regenerative capacity elicited by demineralized bone matrix of different embryonic origins.

In the cranio-maxillo-facial field, extensive research has been conducted to find substitutes for autogeneic bone as a grafting material. The present study examined the effect of demineralized allogeneic bone material of membranous and enchondral origin compared with autogenous bone chips on the healing response in rabbit skull defects. The demineralized bone matrix (DBM) was bioassayed in a critical-size defect rat model. Four trephined calvarial defects were created in each of 14 adult rabbits and the experimental materials implanted into three defects leaving the fourth defect empty for control purposes. The results were assessed by light microscopy and contact radiography after periods of 4 and 15 weeks. The DBM of both origins displayed extensive osteoinductive capacity and early bone production significantly exceeded that of the two control groups. The embryological origin implied minor effects on the initial regenerative response and bone marrow redevelopment. The clinical significance of these findings is discussed.

Animals↗

PubMedDate not supplied

Effect of cortical perforations of both graft and host bed on onlay incorporation to the rat skull.

The mechanisms involved in the integration of autogeneic bone grafts still attract much interest due to their clinical importance. The purpose of this study was to obtain data on the effects of a combination of cortical bone perforations both at the recipient site and the inner layer of a bicortical graft. 12 adult rats obtained femoral or tibial bicortical bone grafts from isogeneic donors to the tibia, one on each leg. On the experimental side, both the recipient bed and the inner cortical graft layer received multiple perforations (0.25 mm in diameter), while on the control side, only perforations of the recipient cortical bed were made. The findings were assessed by routine histology and immunohistochemical analysis for some bone and cartilage matrix proteins after 4 and 20 weeks. The combined cortical perforations of the graft and the host bed induced a locally improved bony incorporation of the graft and a corticalization of the graft marrow, implying improved mechanical stability. The graft height persistence was similar between groups. Intense labelling of the bone matrix proteins was apparent in all bone tissue and by diversified intensity at its various components, demonstrating ongoing remodeling activities. PRELP and fibromodulin mainly outlined the soft tissues surrounding the graft and compact bone sealing off the graft marrow. Immunolabelling contributed a more delicate picture of the mechanisms involved in graft incorporation.

Animals↗

PubMedDate not supplied

Retrospective analysis of one-stage maxillary sinus augmentation with endosseous implants.

The aim of the present retrospective study was to evaluate the results of a one-stage reconstructive procedure using titanium implants placed in iliac corticocancellous bone blocks grafted to the floor of maxillary sinuses. Forty-nine patients received 314 Brånemark implants, of which 171 implants of various lengths were placed in the grafted bone and 143 implants in the adjacent maxillary alveolar process (which includes 11 implants placed in onlay grafts). Five patients also received onlay grafts to the anterior maxilla. Follow-up time was 3 to 49 months after abutment connection, which was performed 9 months after implant placement. Eighty-two percent of the implants were successfully integrated in the grafted area and 84.8% in the adjacent bone. Eleven patients (22.4%) lost one to four implants or a few implants in strategic positions, requiring secondary implant placement prior to the manufacturing of fixed prostheses, whereas 35 (71.4%) received primary fixed restorations. Only two individuals (4.1%) received permanent implant-supported overdentures. Assessments of esthetics, phonetics, and function were made by the surgical-prosthodontic team and compared with those of the patients. Opinions regarding the functional outcome of treatment appeared least correlated. The total implant survival rate compares favorably with other reports.

Alveolar Process↗

PubMedDate not supplied

Dental implant survival in the irradiated jaw: a preliminary report.

Seventeen oral cancer patients (47 to 78 years, mean 67) were treated with external radiation in areas that included future implant sites. Implants were placed in the irradiated jaws after a period of 18 to 228 months (mean 88 months). The patients received 103 implants and were followed for 1 to 62 months (mean 21 months) after implant loading. The cumulative survival rate of the implants after 1 year was 97% in the mandible and 92% in the maxilla. While the irradiation dose used did not affect implant survival, this result may possible be influenced by the addition of hyperbaric oxygen treatment for patients receiving more than 50 Gy. Irradiation for treatment of oral cancer does not seem to reduce the survival rate of implants as compared to those placed in the nonirradiated jaw.

Aged↗

PubMedDate not supplied

Two-stage maxillary sinus reconstruction with endosseous implants: a prospective study.

The aim of this prospective study was to evaluate the results of 2-stage maxillary sinus reconstruction using titanium implants placed into iliac corticocancellous bone blocks previously grafted to the floor of sinuses. Fifty consecutive patients received 314 Brånemark implants of varying lengths; 202 implants were placed in the grafted bone and 112 were placed in the adjacent anterior maxillary alveolar process, which had received buccal onlay bone grafts. Follow-up time was 9 to 48 months after implant placement, which was accomplished 5 months after bone grafting. Eighty-four percent of the implants were integrated into the grafted sinuses and 75% were integrated into the anterior graft. Six patients (12%) lost implants in strategic positions, leading to secondary implant placement prior to fabrication of fixed prostheses. Thirty-eight patients (76%) received fixed prostheses. Only 5 individuals (10%) attained permanent implant-anchored overdentures. One patient lost all implants. The total implant survival rate (80.9%) and the survival rate of the fixed prostheses (100%) compare favorably with other reports.

Adult↗