RESUMO
An addressable electrode array was used for the production of acid at sufficient concentration to allow deprotection of the dimethoxytrityl (DMT) protecting group from an overlaying substrate bound to a porous reaction layer. Containment of the generated acid to an active electrode of 100 micron diameter was achieved by the presence of an organic base. This procedure was then used for the production of a DNA array, in which synthesis was directed by the electrochemical removal of the DMT group during synthesis. The product array was found to have a detection sensitivity to as low as 0.5 pM DNA in a complex background sample.
Assuntos
Técnicas Eletroquímicas/métodos , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Ácidos , Sequência de Bases , Primers do DNA/genética , Indicadores e Reagentes , Microquímica , Microeletrodos , Oligodesoxirribonucleotídeos/síntese química , Oligodesoxirribonucleotídeos/química , Análise de Sequência com Séries de Oligonucleotídeos/instrumentaçãoRESUMO
This article reports on a multicenter evaluation of a novel, sterile, antigen-inactivated, mineralized block allograft in humans during a 3-year developmental period. Consecutive partially edentulous patients (n = 73) with severe localized ridge defects (n = 82) were treated with the material. After 4 to 6 months of healing, tapered screw implants were placed in the grafted bone and subsequently restored. Patients were monitored 25 to 36 months after prosthetic restoration. A biopsy was taken of one patient and submitted for histomorphometric analysis. Block allograft survival was 93% at 12 months, and resorption ranged from none (69%) to slight (0 to 2 mm) (31%) for all surviving allografts. Seven block allografts failed and were removed because of improper contouring, prosthesis impingement, and/or infection. The sites were successfully re-treated and restored with dental implants. Soft tissue dehiscence was successfully treated in seven other sites. Implant survival was 99%. One implant failed without allograft failure. It was replaced with a larger-diameter implant, treated with guided bone regeneration, and subsequently restored. Histomorphometric analysis showed rapid incorporation of the allograft at 6 months without inflammation or necrosis. The block allografts were more technique-sensitive than autografts, which necessitated meticulous surgical technique and follow-up. Short-term results for the block allografts indicated a high degree of predictability, but long-term follow-up is needed.
Assuntos
Aumento do Rebordo Alveolar/métodos , Transplante Ósseo/métodos , Adolescente , Adulto , Idoso , Aumento do Rebordo Alveolar/instrumentação , Parafusos Ósseos , Transplante Ósseo/patologia , Implantação Dentária Endóssea/métodos , Implantes Dentários , Prótese Dentária Fixada por Implante , Feminino , Seguimentos , Sobrevivência de Enxerto , Regeneração Tecidual Guiada Periodontal , Humanos , Arcada Parcialmente Edêntula/cirurgia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Deiscência da Ferida Operatória/terapia , Análise de Sobrevida , Transplante Homólogo , Cicatrização/fisiologiaRESUMO
Autogenous block bone grafts have been highly successful in treating human periodontal defects, restoring esthetics, and developing adequate bone volume for dental implant placement. Limitations in available donor bone, the need for an added surgical procedure, and other potential complications have made the use of allogenic bone graft materials an important alternative. One patient described in this report presented with fractured root syndrome of the right maxillary incisor with severe resorption of the buccal plate. After atraumatic tooth extraction, a staged treatment approach involving localized ridge augmentation with an allogenic iliac bone block material and dental implant placement was used. The host bone completely incorporated the graft with only minor resorption, which enabled the implant to be placed. The allogenic bone block material used in this study was an effective alternative to harvesting and grafting autogenous bone for implant site development. The cases presented in this article clinically demonstrate the efficacy of using a block allograft in generating effective new bone fill for dental implant placement.
Assuntos
Aumento do Rebordo Alveolar/métodos , Transplante Ósseo , Implantes Dentários , Adulto , Reabsorção Óssea/cirurgia , Planejamento de Prótese Dentária , Feminino , Humanos , Incisivo/lesões , Masculino , Doenças Maxilares/cirurgia , Pessoa de Meia-Idade , Osseointegração/fisiologia , Fraturas dos Dentes/cirurgia , Raiz Dentária/lesões , Transplante Homólogo , Cicatrização/fisiologiaRESUMO
A route to bicyclo[n.3.0] ring systems (n = 5-7) has been devised. Key transformations include an intermolecular diyl trapping reaction (1 + 3 --> 4), and fragmentation of the resulting tricyclic cycloadduct 4 (4 --> 5). A variety of diylophiles were examined, including electron deficient (6, 7, 21, 29, 30, 31), electron rich (8), and push-pull cycloalkenes (9, 10, 19, 20).
