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Biomedical subjects

A Scarano

Publications and source records attributed to A Scarano.

80 records · Page 5Linked to original sources
PubMedDate not supplied

Guided bone regeneration using resorbable and nonresorbable membranes: a comparative histologic study in humans.

Resorbable membranes of poly(lactic acid) and poly(glycolic acid) (PLA/PGA) were compared to nonresorbable expanded polytetrafluoroethylene (e-PTFE) membranes in the treatment of defects around titanium dental implants placed in postextraction sockets. Two partially edentulous and three completely edentulous patients requiring implant-supported restorations participated. Sixteen Brånemark implants were placed into extraction sockets and covered with modified titanium cover screws, called harvest cover screws, which allow tissue biopsy at second-stage implant surgery. Seven defects were treated with PLA/PGA membranes, five were treated with e-PTFE membranes, and four were left untreated (control sites). After 6 months of healing, the harvest cover screws were retrieved and processed for light microscopy examination together with the regenerated tissues. Very little or no bone formation was detected in control specimens. The e-PTFE membranes were found to be the most effective barrier material, in that denser and a greater amount of regenerated bone was found. The PLA/PGA membranes produced some bone regeneration when compared to control sites, but to a lesser extent compared to e-PTFE sites.

Adult↗
PubMedDate not supplied

Histologic analysis of the interface of a titanium implant retrieved from a nonvascularized mandibular block graft after a 10-month loading period.

The combined use of bone grafts and osseointegrated implants appears to improve the long-term prognosis of transplanted bone. One question pertaining to the use of grafted bone is whether the biologic reaction to implants placed in grafted bone is the same as that seen under nongrafted conditions. A mandibular discontinuity defect in a 63-year-old female patient was repaired with a nonvascularized block graft into which 3 titanium implants were placed. After a 10-month loading period, one of the implants was retrieved and treated to obtain thin ground sections. The histologic examination showed mature bone in close contact with the implant surface; no gaps, fibrous tissue, or inflammatory cells were seen at the interface. No resorption phenomena were present. The bone at the interface was highly mineralized. The features of the regenerated bone and the bone-implant interface in grafted bone were similar to those seen in nongrafted situations; no differences were found with results presented in the literature concerned with retrieved implants placed into vascularized grafts.

Bone Regeneration↗
PubMedDate not supplied

Clinical and histologic features of a nonaxial load on the osseointegration of a posterior mandibular implant: report of a case.

The authors report on the clinical and histologic features of a single implant replacing a mandibular molar, which fractured after a 1-year loading period. Because of anatomic factors, the implant had been placed in an angulated position. The histologic examination showed a very high percentage of bone-implant contact. The bone located at the interface with the implant was mature, compact, and had few marrow spaces. No resorption areas were present, and no connective tissue was seen at the interface. Most likely, the lateral nonaxial forces exerted on the implant created very high bending moments. These forces produced a fracture of the implant, although no loss of osseointegration was observed at the interface.

Adult↗
PubMedDate not supplied

Light and scanning electron microscopic report of four fractured implants.

Although they are fortunately rare, implant fractures can cause significant problems for both clinicians and patients. The authors present a light and scanning electron microscopic study of four fractured implants in two patients. Both patients had parafunctional habits (bruxism), hypertrophic masticatory muscles, and wear of occlusal surfaces. The scanning electron microscopic study of the fractured surfaces of all four implants showed the presence of fatigue striations. Bending overload was probably created by a combination of parafunctional forces, bone resorption, posterior location of the implants, and implant diameter.

Aged↗
PubMedDate not supplied

Rigid fixation by means of titanium mesh in edentulous ridge expansion for horizontal ridge augmentation in the maxilla.

The edentulous ridge expansion has been introduced in recent years to reestablish an appropriate alveolar ridge width. This technique consists of the placement of implants in the space formed after the dislocation of the buccal plate in a labial direction. In guided bone regeneration, the quantity of bone regenerated under the membranes has been demonstrated to be directly related to the amount of the space under the membranes. This space can diminish as a result of membrane collapse. To avoid this problem, a new technique of edentulous ridge expansion, which involved the use of a titanium mesh barrier to protect the regenerating tissues and to achieve a rigid fixation of the bone segments, was used in association with autologous bone in 25 patients. At second-stage surgery in all patients, it was possible to see tissue, under the mesh, that had the macroscopic characteristics of mature bone and was superficially covered by a thin soft tissue layer. The microscopic examination showed that all autologous bone particles were embedded in newly formed bone. The use of a rigid mesh can assist bone regeneration in non-space-making defects, since it probably does not interfere with the blood flow to the underlying tissues because of the presence of microholes within the mesh.

Adult↗
PubMedDate not supplied

Clinical and histologic evaluation of an active "implant periapical lesion": a case report.

A new entity called "implant periapical lesion" has recently been described. This lesion could be the result of, for example, bone overheating, implant overloading, presence of a preexisting infection or residual root fragments and foreign bodies in the bone, contamination of the implant, or implant placement in an infected maxillary sinus. This case report describes a titanium implant that was placed in the maxillary premolar region. A fenestration involving the middle portion of the implant was present. After 7 months, the apical portion of the implant showed radiolucency. This lesion rapidly increased in size and a vestibular fistula appeared. A systemic course of antibiotics was not successful, and the implant was then removed. The histologic examination showed the presence of necrotic bone inside the antirotational hole of the implant. The etiology of the implant failure in this instance could possibly be related to bone overheating associated with an excessive tightening of the implant and compression of the bone chips inside the apical hole, producing subsequent necrosis.

Adult↗
PubMedDate not supplied

Histologic and histomorphometric analysis of the bone response to machined and sandblasted titanium implants: an experimental study in rabbits.

The aim of this study was to make a comparative analysis between the bone response to machined and sandblasted implants. The sandblasting was done with 150-microns aluminum oxide particles. Under scanning electron microscopic examination, the machined implants presented typical machining grooves, while a very rough, highly irregular surface with depressions and indentations was present on the sandblasted implants. Light microscopy showed a different bone growth pattern on machined (implantopetal growth) and sandblasted (implantofugal growth) implants. No negative effects on the rate of bone growth were observed in spite of the presence of aluminum ions. The histomorphometric analysis showed that sandblasted implants presented, from the third week onwards, a significantly higher contact percentage (P < .0001). These values could point to higher osteoconductivity as a result of the higher surface roughness of sandblasted surfaces.

Aluminum↗