ISSN:1056-6163    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:1056-6163    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The loss of crestal bone associated with dental implants is a significant clinical phenomenon. The occurrence of such bone loss will often compromise long-term prognosis and, if extensive, ultimately lead to failure. Relatively few studies have focused on the reasons for loss of crestal-supporting bone around implants, although numerous explanations for the phenomenon have been proposed. This retrospective investigation examines one potential causative factor for implant-associated crestal bone loss, which has only recently received attention, i.e., location of the implant/transmucosal abutment interface (ITAI) relative to the crestal bone. A retrospective clinical evaluation of 350 individual implants in 255 patients indicates a direct relationship between subgingival placement of the ITAI and loss of crestal supporting bone. In addition, scanning electron microscopic examination of 45 failed implants showed significant plaque accumulation at the ITAI, the transmucosal abutment/prosthesis interface (TAPI), and the interface between the implant smooth collar and subjacent plasma-spray coated surface.

ISSN:1056-6163    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

When placing implants in the mandible or maxilla, it is important for clinicians to understand the process of bone remodeling, the different types of bone, and how these factors can affect the integration of osseous dental implants. Approximately 0.7% of a human skeleton is resorbed daily and replaced by new healthy bone. With aging and metabolic disease states, the normal turnover process may be reduced, resulting in an increase in the mean age of the present bone. This increase can affect the placement and integration of implants. Herein follows a discussion of different types of bone cells, the metabolism of bone, the microscopic, macroscopic, and molecular structure of bone, and the process of bone modeling and remodeling.

ISSN:1056-6163    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

All physiologic biomechanical processes are interrelated and, therefore, reactive, which produces an accumulative effect that can cause implant overload. A new approach called “therapeutic biomechanics” suggests using corrective procedures to reduce implant loading. The head of the implant is positioned as close to the midline of the restoration as possible. Implant inclination may be required, but it produces less torque (moment) than horizontal implant offset. Posterior cross occlusion should be used where possible to decrease horizontal implant offset. Angulated, or reangulated abutments provide access or parallelism as needed. The posterior cusp inclination should be markedly reduced. When a vertical overlap is present anteriorly, a horizontal stop on the maxillary lingual surface redirects harmful lateral force to be vertical toward the implant and supporting bone. Because of physiologic variability, creating a modified centric occlusion that contains a 1.5-mm fossa will produce vertical resultant force within this range of motion rather than lateral force.

ISSN:1056-6163    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Clinical and histologic evaluations of a synthetic bone were performed in 224 patients in a well-monitored environment. This material (Bioplant®HTR®, Bio-plant Inc., South Norwalk, CT) was used to obliterate cysts, treat periodontal defects, correct jawbone contours and deficiencies, and gain sufficient support for the placement of dental implants in maxillary subantral augmentation. Implants were positioned either at the time of the synthetic bone graft or after the new supporting tissue was formed.Evidence of new bone formation between the synthetic granules and host tissue was observed during histological examinations. After the material was placed, tissue that could strengthen and augment the inferior wall of the maxillary sinus formed in 3 months. This was observed both clinically and radiographically. After 8 to 12 months, this tissue provided sufficient hard tissue support for the placement of dental implants.This clinical study reconfirmed the applicability of a synthetic bone for bone replacement and augmentation in oral and maxillofacial surgery. No complications caused by infection, inflammation, or rejection of the implanted graft material were observed.

ISSN:1056-6163    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:1056-6163    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:1056-6163    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

A variety of successful endosseous dental implants with different surface forms are currently available for clinical use. These all achieve implant-to-bone fixation primarily (if not totally) through mechanical interlock of bone with implant surface features introduced by design or chance during implant fabrication. Equally important to establishment of rigid fixation is the rate at which it is achieved, because faster rates allow earlier implant loading and less chance of inadvertent early loading that might prevent implant “osseointegration.” Investigations of surface modification to favorably affect osteoconductivity and bone bonding represent an active area of research in the field of dental implant development. This article presents a review of available surface designs and future research directions for improved devices.

ISSN:1056-6163    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

There are various ceramic coatings available for dental implants. From a commercial stand-point, plasma-sprayed hydroxyapatite (HA) is the most popular. These coatings are typically partially amorphous after processing and contain crystalline phases other than HA. Plasma-sprayed HA and the other bioactive ceramic coating materials have been shown to enhance bone apposition as compared with uncoated metal implants. Some of the other available materials include the bioglasses, other calcium phosphates such as fluorapatite and tricalcium phosphate, and the inert ceramics such as alumina. The plasma-spray process is not optimum for all types of ceramic coatings, because it is not suitable for coating porous surfaces; the exact control of structure and chemistry is difficult with this process, and bond strength is not as high as is desired for some applications. Alternative methods for coating include sol-gel processing, ion beam and radio frequency (RF) sputtering, pulsed laser deposition, hot isostatic pressing, and electrophoretic deposition. The use of osteoinductive agents in conjunction with ceramic-coated implants is of current interest, and the degree and type of bonding of these agents appear to vary with the composition of the ceramic coating. Because there seems to be no satisfactory means of incorporating osteoinductive agents into ceramic coatings during any of the conventional coating procedures, the best approach seems to be to diffuse the agents into the coating after processing. Other possibilities include the tethering of the agents to the surface of the ceramic by suitable organic molecules or the placing of the agent in some carrier material such as a cement, which is placed around the implants.

ISSN:1056-6163    

出版商:OVID    

年代:1998

数据来源: OVID