ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

To set up a three-dimensional culture model of endosseous implant material- osteoblast, titanium (Ti) discs were placed onto confluent cellular layers of human fetal osteoblasts that were cultured in calcifying conditions. Follow-up observations of living cells with phase-contrast microscopy and histological observations of the cell-Ti disc interface with ordinary microscopy and transmission electron microscopy were used to monitor and verify the formation of threedimensional cellular structures at the osteoblast-Ti disc interface. These methods were further used to study osteoblast cell behavior during the early stage of bone healing in this three-dimensional cellular model. The follow-up observation showed that, upon the placement of the Ti disc, cells migrated from the cellular layer and attached to the rim of the disc, forming cell bridges. Cells continued to attach and orient throughout the culture time. A cellular multilayer at the osteoblast-Ti interface was formed, which resulted in the threedimensional model. Furthermore, transmission electron microscopy observation showed that there was a mineralizing process at the osteoblast-Ti disc interface just like bone, which confirms the reality of this model. Histological observations with conventional microscopy demonstrated the interfacial relation between biomaterial and cells. If osteoblasts were replaced by other types of cells, this model could be used to study the other kinds of interfaces.

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The clinical success of dental implants is governed in part by surface properties of implants and their interactions with the surrounding tissues. The objective of this study was to investigate the effect of heat-treated titanium (Ti) surfaces on protein adsorption and osteoblast responsesin vitro. The passivated Ti samples used in this study were either nonheat-treated or heat-treated at 750°C for 90 minutes. Using x-ray diffraction analyses, no oxide peaks were observed on the nonheat-treated surfaces, suggesting an amorphous oxide. Crystalline rutile TiO2peaks were observed on the heat-treated Ti surfaces. The contact angles of water on heat-treated Ti surfaces (32.0 ± 2.5 degrees) were statisti cally lower compared with the nonheat-treated Ti surfaces (47.7 ± 2.3 degrees). In addition, the mean albumin concentration on the nonheat-treated Ti surfaces (3.57 ± 0.33 μg/mL) was observed to be significantly different from the mean albumin concentration on heat-treated Ti surfaces (2.25 ± 0.26 μg/mL). In the presence of an osteoblast precursor cell line, significantly different hexosaminidase activity, protein production, and alkaline phosphatase activity were observed for cells grown on heattreated Ti surfaces compared with nonheat-treated Ti surfaces.

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Accurate master casts are essential for the construction of implant-supported prostheses with a precision of fit. The stability of the abutment replicas in the master cast is critical in the accurate reproduction of the patient's oral presentation. The Periotest method is an objective method of quantifying mobility in a tooth and implant. Eighteen gypsum implant master casts containing two brass abutment replicas per cast were evaluated. The abutment replicas were measured three times each for a total of 108 measurements. The mean periotest values and standard deviations were calculated for the master casts and the abutment rep licas. The abutment replicas displayed mean periotest values that ranged from + 1.3 to −8.0. The study shows that there are significant differences between stable and unstable implant master casts (P= 0.0001, ANOVA-Fisher's protected least significant difference) and abutment replicas (P= 0.0001, Contrast test). The Periotest method will quantify differences in gypsum stone implant master casts as well as the prosthesis supporting brass abutment replicas that are an integral part of the master cast.

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

A photoelastic and strain gauge analysis was performed to evaluate the stress transferred to implants through the provisionalcement-retained, the permanentcement-retained, and the screwretained prostheses. The deflections of the prostheses at the time of the loading were also measured. In the single crown test, the provisionalcement-retained crowns transferred less stress. In the two-unit fixed partial denture test, there were no differences between the three different prostheses. In the two-implant supported distal cantilevered prostheses, the screw-type and the permanent-cement-retained prostheses developed more stress around the apex of both implants. The permanent-cement-retained prostheses acted almost the same as the screw-type.

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

In an attempt to improve patient satisfaction during the healing period after placement of implants, mini-transitional implants (MTIs) have been advocated to allow immediate use of temporary dentures and to prevent transmucosal loads over the definitive implants. Twelve edentulous patients received two screw implants each in the predetermined mandibular canine region. At the time of surgery, six patients had two MTIs placed medially to the permanent ones. The flap was repositioned allowing transmucosal penetration of MTIs. Patients left the operating room wearing their relined lower den tures. The results indicated that MTIs integrated sufficiently in bone, giving successful immediate support for the transitional prosthesis and allowing proper mucosal healing. Two of these transitional implants showed mobility three months after phase 1 surgery. After loading the final implants, patients who had MTI-supported dentures showed bone loss that was not significantly different from the control group.

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Surgical flap procedures currently used for the placement of endosseous implants often can result in damage to the interdental papilla with subsequent poor esthetics. A simple technique is presented whereby the implants are placed by using a tissue punch and without raising a full thickness flap. At no time is the subperiosteal soft tissue flap raised, and the integrity of the interdental papilla is never disrupted. There is no discontinuation of the alveolar blood supply of the surrounding osseous tissue. In the authors' experience, there has been a significant reduction in postoperative discomfort. It is proposed that this technique warrants further evaluation, especially to compare the rate of bone resorption, because it is hypothesized that because of lack of discontinuation of the blood supply, there might be reduced bone resorption compared with conventional flap procedures.

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The immediate placement of a dental implant into a fresh extraction socket has been limited in many instances by the quantity of bone that remains after the extraction. This article presents two clinical cases that demonstrate successful regeneration of alveolar ridges in which there was extensive loss of the buccal plate of bone. This lack of alveolar process impeded the immediate placement of dental implants into fresh extraction sockets. The surgical technique performed in these cases was based on the principles of guided bone re generation using a demineralized freeze-dried bone membrane. The bone membrane acted as an efficient barrier that excluded the nonosteogenic tissues. Bone formation took place for the placement of endosseous dental implants 8 months after the procedures were initiated. These human clinical cases confirm positive results of previous animal findings.

ISSN:1056-6163    

出版商:OVID    

年代:1999

数据来源: OVID