ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

To study the effects of a modified sandblasting surface treatment on the osseointegration of dental implants at the level of interfacial biomechanics, anin vivopullout test was conducted using bone-interfacial shear strength as a criterion. Titanium implants were inserted into the medialis condyli of dogs and harvested 2, 4, and 12 weeks after insertion. Shear strength was determined with an Instron pullout tester. Observation and analysis of the surface of modified sandblasted implants after pullout at 12 weeks were performed with scanning electron microscopy and x-ray spectroscopy.Results showed that the shear strength of implants with a modified sandblasted surface was about five times as high as that of implants with a smooth surface. We concluded that the rough surface of titanium dental implants created by the modified sandblasting treatment can greatly enhance the shear strength at the dental implant-bone interface and that, with this enhancement, the secondary micro-pores play a much more important role in implant-bone bonding.

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

In this article, we report the results of analyses of bone healing around four types of dental implants. Five implants of each type were inserted into the proximal tibia metaphysis of adult New Zealand rabbits and were analyzed using computerized histomorphometry 12 weeks after implantation. Hydroxyapatite-coated implants showed more direct bone contact and more lamellar bone in the threads than the titanium implants. There was a significant correlation between an increase in the percentage of mineralized tissue in the threads of metallic implants and cellular density around the implant, indicating less lamellar bone in contact with metallic implants.

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Osseointegration capacity of the different metallic implants depends on several variables. Osseointegration can be evaluated by using different methodologies, such as light microscopy and scanning or transmission electron microscopy. The aim of this study was to develop a qualitative and quantitative method to evaluate the presence of bone tissue on large metallic surfaces. A laminar implant was placed in each tibia of 10 Wistar rats. The animals were killed 30 days after surgery. Tibiae were resected, one for embedding in methyl methacrylate and the other for evaluation by energy-dispersive x-ray analysis. Light microscopy revealed osseointegration. Observation of the implant surface by scanning electron microscopy revealed the presence of a coating on the metallic surface that was rough in some areas and smooth in others. Analysis of the coating by energy-dispersive x-ray analysis showed the presence of Ca and P. Eighty percent (±10%) of the metallic implant surface exhibited bone tissue. After confirmation of the occurrence of osseointegration capacity using light microscopy, the method described here allows qualitative and quantitative evaluation of the bone tissue found on large metallic surfaces.

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

In this study, the functional stresses in alveolar bone created by restorative materials used in implant-supported prostheses were determined by the photoelastic stress analysis method. A photoelastic resin mandibular model, hollow-cylinder implants (3.5 mm diameter, 10 mm length), and fixtures and superstructures made of five different prosthetic materials were used. Vertical and 45-degree inclined loads were applied to the model. Subsequently, color photographs of the force line distribution observed on a polariscope were taken. Differences between vertical and inclined loads were statistically significant for all prosthetic materials(P< 0.01). The greatest stress distribution around the apex of the implant was observed with Ceramco II porcelain, followed by Biodent acrylic. The ArtGlass and Elcebond CCV composite materials had equal values, whereas Verebond Ni-Cr alloy showed minimum stress distribution.

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID