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Biomedical subjects

S Isaksson

Publications and source records attributed to S Isaksson.

29 records · Page 2Linked to original sources
PubMed1992

Aspects of bone healing and bone substitute incorporation. An experimental study in rabbit skull bone defects.

After an initial assessment of the experimental approach this experimental project was undertaken to study the regenerative response and incorporation of various implanted materials in calvarial bone defects in rabbits. Four 5-mm full-thickness defects were trephined in the frontal and parietal bones of the rabbits. After removal of the circular bone plugs the defects were used as recipient sites for inlay bone tissue and bone substitutes. In five separate studies the impact of bone regeneration of autogeneic bone grafts or eight bone substitutes were evaluated mainly by contact radiography, light microscopy and morphometry. The observation periods were four and 15 weeks. The main findings were: Autogeneic bone chips offered only minor advantages over controls in the model used and, also, differences in bone regeneration between diversified amounts of bone chips were negligible. In contrast, after bone paste implantation a cellular and mature bone was rapidly produced. Natural bone mineral (Bio-Oss) and synthetic dense hydroxylapatite ceramic proved to be biocompatible and a definite long term bone regeneration around all implants regardless of granulae size or resorbability was observed. Initial bone regeneration in and around the Bio-Oss particles was more extensive. Demineralized bone matrix of membranous and enchondral origins displayed extensive osteoinductive capacity and early bone production significantly exceeded that of control groups. The embryonic origin implied minor effects on the initial regenerative response only. Lyophilized bone allografts of two embryonic origins showed a low osteoinductive potential and a similar fashion of bone regeneration. No marked difference between these groups were displayed. HTR-polymer alone or combined with membraneous mineralized autogeneic bone chips showed a more rapid early bone regeneration than the groups containing lactomer beads, resorbable gel and controls. Also, the HTR-material proved to be a well-tolerated implant material by the recipient tissue bed.

Animals↗
PubMed1990

Immunocytochemical analysis of receptors for estrogen and progesterone in fine-needle aspirates from human breast carcinomas.

Monoclonal antibodies were used for a preoperative analysis of estrogen receptors (ERs) and progesterone receptors (PgRs) in fine-needle aspirates from 44 primary human breast carcinomas. The semiquantitative receptor values obtained in cytologic specimens correlated well with those from enzyme immunoassay analysis on surgically removed tumor tissue (r = 0.74 for PgR; r = 0.75 for ER). Cytologic smears showed a heterogenous tumor cell distribution of ER and PgR in 29 and 23 cases, respectively. The results suggest that measurement of the ER and PgR in cytologic smears is an accurate and reliable technique that can be performed on a minimum amount of tissue.

Aged↗
PubMed1990

Regeneration of cranial suture and bone plate lesions in rabbits. Implications for positioning of osteotomies.

The positioning of osteotomies in intramembranous cranial bone was studied by exploring the pattern of bone regeneration in growth areas (the sutural region) as compared to that of the bone plate proper. Trephine defects in the left coronal suture area and the right parietal bone were produced in fifty-nine young rabbits. A pilot study to refine operative and analytical methods comprised 22 animals. The experiments were terminated at one, three, and six weeks after surgery. The bone regenerative response was assessed by x-ray planimetry, plain microscopy, enzyme histochemistry, and fluorescent labelling. Only minor divergences in healing capacity between the two defects were found. No adverse effects on the growth process were indicated. As to clinical management, the findings suggest that osteotomies designed to traverse sutural areas will, under normal circumstances, regenerate in a similar manner and rate to adjoining bone plates.

Acid Phosphatase↗
PubMed1990

Cryosurgical treatment of mucocele in children.

Cryosurgery of superficial mucoceles located in the lower lip of eight children is reported. The treatment did not require administration of local anesthetics and was easily performed and well-tolerated even by small children. Healing proceeded uneventfully in all patients. No recurrence during a 1-year follow-up period was observed. Cryosurgery proved to be an effective and essential tool in the management of mucocele in children.

Child↗
PubMed1989

Management of craniotomy in young rabbits.

A safe and easy-to-manage technique for various craniotomy procedures in young rabbits has been developed. This technique, which minimizes the need for special instrumentation, has been tested in 90 animals with a minimal mortality and morbidity: one death perioperatively caused by sagittal sinus bleeding and one rabbit disclosing a brief period of postoperative illness, respectively. The technique, including postsurgical strategy, is described in detail.

Animal Welfare↗
PubMedDate not supplied

Guided bone regeneration of cranial defects, using biodegradable barriers: an experimental pilot study in the rabbit.

The aim of this study was to test if a biodegradable barrier could be used to achieve proper bone healing of full-thickness trephine skull defects, applying the biological principle of guided tissue regeneration (GTR). Two New Zealand white rabbits were used. In each animal, 2 circular through-and-through bone defects with a diameter of 8 mm were created in the midline of the frontal and parietal bones of the calvarium. One defect was covered with the mucoperiosteal flaps without placement of an intervening membrane barrier (control). One test defect (test 1) was covered by a biodegradable, non-porous polylactic acid membrane on the outer (supra-calvarial) side of the defect, and 2 test defects (tests 2 and 3) were covered by similar membranes on both the outer and the inner aspects of the defects, prior to flap closure. 6 weeks postsurgically, the animals were sacrificed and the defect areas including surrounding tissues were harvested for histological preparation. The control defect was essentially occupied by supra-calvarial soft tissue, located in direct contact with the dural tissue. In the test cavities, there was a continuous bridge of regenerated bone extending from one edge of the defect to the other, although in test 1 not attaining the same thickness as the bone bordering the defect. In the 2 other test defects, the regenerated bone had reached a thickness almost corresponding to that of the surrounding bone. The bone regeneration was achieved without recourse to adjunctive bone graft materials.(ABSTRACT TRUNCATED AT 250 WORDS)

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

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

Implant-supported overdenture therapy: a retrospective study.

All patients (n = 46) treated with implant-supported overdentures at the Department of Prosthetic Dentistry, Dental and Medical Health Centre, Halmstad, Sweden, from 1986 to 1993 were studied. The clinical examination was completed in 1994. The material was divided into two subgroups: Group A had been initially treatment planned for an implant-supported overdenture, and Group B had been planned for fixed prostheses but because of loss of implants before loading, treatment with a fixed prosthesis was not possible. The authors present their experience and patient reactions to overdenture therapy in two defined groups of patients. The implant failure rate before loading for Group A (n = 12) was 15% (six implants out of 39), and the rate before loading for Group B (n = 29) was 43.6% (68 implants out of 156). After prosthodontic treatment in Group A, the implant success rate after loading was 87.9%, and the overdenture stability was 84.6%. In group B, 17 implants placed in the maxillae were lost after overdenture therapy, which resulted in an implant success rate of 79.3%. A total of eight overdentures, all of which had been placed in the maxillae, were lost, resulting in an overdenture stability of 73.3%. In this study "change of retentive clips" was the predominant prosthodontic complication related to the overdentures, especially in Group B. Most of these complications (62%) occurred in patients with clinical signs of bruxism. Patient reactions to treatment with an overdenture were positive regarding esthetics for both groups. More negative views were recorded in Group B than in Group A in response to function and retention of the overdenture.

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↗