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Biomedical subjects

B E Becker

Publications and source records attributed to B E Becker.

At least 37 records · Page 2Linked to original sources
PubMed1995

Replacement of maxillary and mandibular molars with single endosseous implant restorations: a retrospective study.

This retrospective report presents findings on 22 patients with 24 implants replacing single molars with implant-supported restorations. Patients with known bruxism habits were not considered for single-molar implant replacement. The patients underwent follow-up for an average of 24 months. The cumulative success rate was 95%, which reflects the loss of one 5 x 6 mm wide implant. Eleven implants were placed in edentulous ridges, and 13 were placed in extraction sockets. Most of the implants were placed in type B and C bone quantity and type 2 and 3 bone quality. All implants were restored on abutments with nonrotating gold cylinders. The occlusion for all restorations was developed to minimize centric contacts and lateral interferences. The frequency of gold retaining-screw loosening was obtained for 21 patients. The gold retaining screws loosened in eight implants between one and three times (38%). No incidence of crown or implant fracture occurred. Within the limits of this study, replacement of single-tooth molars by implant-supported restorations was predictable; however, a high incidence of gold screw loosening was seen.

Aged↗
PubMed1995

Human demineralized freeze-dried bone: inadequate induced bone formation in athymic mice. A preliminary report.

The purpose of this study was to test the osteoinductive properties of demineralized freeze-dried bone (DFDBA) randomly purchased from four commercial bone banks. Twenty-five (25) milligrams of bone from each of the banks was implanted into the hindquarter muscles of athymic mice. Two samples from each of the banks were compared with samples from the other banks. A total of 16 implants were grafted into 8 mice. Two additional mice served as controls. One mouse received an implantation of deactived human cortical bone matrix (DBM) (negative control). The other mouse received an implant of human bone morphogenetic protein/non-collagenous proteins (hBMP/NCP) infused to surface demineralized human cortical bone (positive control). At 21 days the mice were killed, the hindquarters were photographed, and the tissues were prepared for histologic evaluation. Of the 16 commercial DFDBA implants, 12 were available for histologic evaluation. There was no radiographic evidence of bone formation for the DFDBA implanted mice or the DBM implants. Small bone ossicles were scarcely visible in the hindquarters of the mouse which received the hBMP/NCP infused bone. Histomorphometric analysis was used to determine the percentage of new and dead bone. The bone was measured in pixels. The predominant histologic feature of the DFDBA implants was non-vital bone chips with minimal amounts of new bone. The average amount of non-vital bone ranged from 78.4% to 92.5%. There was no evidence of bone formation for the DBM implants. The average amount of bone for the mouse which received hBMP/NCP was 96%. The results of this pilot study indicate that commercially-available DFDBA induced clinically insignificant amounts of bone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

A comparison of demineralized freeze-dried bone and autologous bone to induce bone formation in human extraction sockets.

The purpose of this study was to test the bone-forming capacity of demineralized freeze-dried bone (DFDBA) and autologous bone grafts in extraction sockets. Seven paired sites were grafted with either DFDBA or autologous bone. The sites were reentered between 3 and 13 months for the purposes of obtaining biopsies of the grafted sites and to place endosseous implants. Biopsies from 6 of the 7 grafted sites were evaluated for new bone formation. DFDBA sites revealed the presence of dead particles of DFDBA with no evidence of bone formation on the surfaces of the implanted particles and no evidence of osteoclastic resorption of the bone particles. Biopsies from the 6 autologous sites revealed vascular channels with woven and lamellar bone. Some specimens had retained cortical, non-vital bone chips. These bone chips were undergoing active osteoclastic resorption. The results of this study questions the use of DFDBA as a bone inductive graft material.

Alveolar Process↗
PubMed1994

Localized ridge augmentation using absorbable pins and e-PTFE barrier membranes: a new surgical technique. Case reports.

This paper presents a new surgical technique to promote bone formation in localized alveolar ridge defects. The objective was to regenerate sufficient bone volume for implant placement. The technique is dependent on careful defect debridement and the use of absorbable orthopedic pins, which serve as tent poles and prevent the e-PTFE barrier membranes from collapsing into the defects. The three defects treated with this technique were completely resolved with new bone, and implants were successfully placed into the augmented ridges. Biopsies from the treated sites revealed new bone formation.

Adult↗
PubMed1993

Periodontal regeneration updated.

Techniques in treating periodontal disease are discussed to provide insight about which technique fits each clinical situation. New developments provide possible regeneration of new cementum, periodontal ligament and alveolar bone, resulting in a new periodontal attachment.

Animals↗
PubMed1993

Treatment of mandibular 3-wall intrabony defects by flap debridement and expanded polytetrafluoroethylene barrier membranes. Long-term evaluation of 32 treated patients.

The purpose of this study was to evaluate the healing potential of deep, primarily 3-wall intrabony defects which were treated by flap debridement and expanded polytetrafluoroethylene (ePTFE) membranes and followed for extended time periods. All of the treated defects were in the mandibular arch. Thirty-two patients were treated and re-examined at an average of 3 years 5 months. Twenty-four of these patients had re-entry procedures at the second examination. Sixteen of these patients were examined a third time at an average of 4 years 3 months. The patients were evaluated for changes in probing depth (PD), clinical attachment level (CAL), recession, changes in crestal resorption, and defect bone fill. The paired t-test for related samples was used to test for differences between examinations. Between Exams 1 and 2 there was a statistically significant reduction of pocket depth (3.8 mm), gain in clinical attachment level (4.2 mm), and an increase in recession (-1.2 mm). For the 24 patients who had re-entry procedures there was an average defect fill of 4.3 mm (P < 0.0001) and 0.33 mm of crestal resorption (P < 0.0001). The 16 patients who were examined 3 times sustained decreases in PD, gains in CAL, and recession recorded at the second examination. These changes were statistically significant at Exam 3. The results of this study demonstrate that deep, 3-wall intrabony defects treated by debridement and ePTFE barrier membranes will have significant decreases in PD, gains in CAL, recession, decreases in crestal resorption, and gains in bone fill.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Bone Loss↗
PubMed1993

Delivery of primary care to the physically challenged.

The specialty of physical medicine and rehabilitation evolved beyond conventional medical views to include consideration of the needs of the physically disabled person's function and quality of life. A care delivery system of medical rehabilitation programs and services then evolved. Recently, the United States' health care system has been recognized as being deficient in meeting the on-going health care needs of the physically disabled after they have completed medical rehabilitation needs. We discuss the history of the health care needs of the physically challenged and we examine current issues of need and delivery of services. We also describe an innovative model program designed to meet those needs.

Delivery of Health Care↗
PubMed1992

A comparison of ePTFE membranes alone or in combination with platelet-derived growth factors and insulin-like growth factor-I or demineralized freeze-dried bone in promoting bone formation around immediate extraction socket implants.

The purpose of this study was to compare bone promotion around implants which were augmented with ePTFE membranes alone or in combination with cortical demineralized freeze-dried bone (DFDB) or the combination of platelet derived growth factor-BB (PDGF) and insulin like growth factor I (PDGF/IGF-I). Membranes were placed over titanium implants which had been inserted into fresh extraction sockets with large buccal dehiscences. Twenty-four implants were placed in 4 dogs. At 18 weeks clinical bone height measurements were taken, the animals were sacrificed, and all specimens retrieved for histologic evaluation. Clinically, a significant gain in bone levels was present in both the ePTFE membrane alone group (P < 0.005) and PTFE plus PDGF/IGF-I group (P < 0.01), but not in the PTFE plus DFDB group. Results from histometric measurements revealed an approximately 2-fold increase in the percentage of implant surface in contact with bone, area of bone adjacent to the implant surface, and in the total length of the implant surface in contact with bone in the dehiscence defects treated with ePTFE plus PDGF/IGF-I compared to the defects receiving ePTFE membranes alone (each P < 0.05). The response to the DFDB was highly variable and it did not significantly improve the efficacy of the PTFE membranes for any parameter measured. The distance from the outer surface of the new bone to the implant surface was statistically significant for ePTFE membranes alone and membranes plus PDGF/IGF-I. The results demonstrated that clinically, ePTFE membranes alone or ePTFE membranes with PDGF/IGF-I were equally effective in promoting bone growth around the implants. Histologic measurements demonstrated that sites treated with ePTFE membranes plus PDGF/IGF-I had the highest bone density compared with sites which received ePTFE membranes alone or with ePTFE membranes and DFDB. The results of this study question the use of DFDB and support the use of ePTFE membranes alone or with PDG-F-BB/IGF-I as potential methods of promoting bone formation around dental implants.

Alveolar Bone Loss↗
PubMed1991

Guided tissue regeneration for implants placed into extraction sockets: a study in dogs.

Twelve 10 mm implants were placed into immediate extraction sockets in dogs. Six implants were isolated with PTFE membranes and 6 sites served as controls. Standardized clinical measurements were taken at test and control sites. At 18 weeks the dogs were anesthetized and flaps were laid for the purpose of obtaining clinical measurements. The average gain of bone around augmented implants was 2.6 mm, while control sites had an average bone gain of 1.0 mm. Ridge width adjacent to augmented sites increased by 1.2 mm and control sites had an increased width of 0.6 mm. Histologic evaluation of test and control specimens showed greater bone formation around augmented implants. Implants augmented with PTFE membranes had clinically significant amounts of bone regeneration when compared with controls.

Alveolar Process↗
PubMed1991

Regeneration procedures: grafting materials, guided tissue regeneration, and growth factors.

Flap debridement, bone grafting, and guided tissue regeneration have the capacity of regenerating bone, periodontal ligament, and cementum. Alloplastic materials are used to fill periodontal defects, and healing occurs by repair. While varying amounts of new bone may form with allografts, a long junctional epithelium is usually the mode of attachment. Flap debridement has been reported to successfully treat multiple walled intrabony defects. Healing results in bone regeneration. However, there is probably a long junctional epithelium adjacent to the root. Defects treated by guided tissue regeneration have been demonstrated to heal with new cementum, periodontal ligament, and bone. Recently, growth factors have been discussed as a possible means of enhancing wound healing.

Bone Transplantation↗
PubMed1990

Clinical and microbiologic findings that may contribute to dental implant failure.

Clinical and DNA probe analysis were used to evaluate 36 failing implant sites in 13 patients. Failing implants showed evidence of increased mobility and a high incidence of peri-implant radiolucencies in radiographs. The probing depth was greater than 6 mm in 58% of the sites measured. Moderate levels of Actinobacillus actinomycetemcomitans, Bacteroides intermedius, and Bacteroides gingivalis were detected with DNA probe analysis.

Actinobacillus↗
PubMed1988

Personality differences and stressful life events. Differences between treated periodontal patients with and without maintenance.

The purpose of this study was to determine whether personality differences exist between patients who have had periodontal therapy and continued in maintenance compared with those who have had periodontal therapy and no maintenance. In addition, an attempt was made to determine whether there were differences in reactions to stressful life events among the 2 groups of patients. Patients were evaluated for personality differences using the adjective check list. A background questionnaire was used to gather personal data and information pertinent to stressful life events. The maintained group had a more positive image of themselves. They had higher achievement, endurance and affiliation scores than did the patients without maintenance. The unmaintained group had higher negative aggression scores, a higher incidence of stressful life events, and less stable personal relationships in their lives.

Attitude↗