摘要:

The aim of this study was to evaluate the soft tissue conditions at osseointegrated oral implants in relation to the width of masticatory mucosa. Thirty‐nine patients who had received a full‐arch fixed bridge reconstruction ≥ 10 years ago or a partial reconstruction ≥ 5 years ago on a total of 171 implants ad modum Brsnemark were included in the study. The examinations involved assessments of plaque, gingivitis, bleeding on probing, probing depth, width of masticatory mucosa and marginal tissue mobility. Simple correlation analysis as well as multiple regression analysis were performed to evaluate relationships between recorded parameters. The results showed that 24% of the sites were lacking masticatory mucosa, and an additional 13% of the implants had a width of less than 2 mm. Mobility of the facial marginal soft tissue, i.e., lack of an attached portion of masticatory mucosa, was observed at 61% of all implants. No major differences in the clinical parameters examined were found between sites with and without an “adequate” width of masticatory mucosa. Multiple regression analyses revealed that neither the width of masticatory mucosa nor the mobility of the border tissue had a significant influence on (i) the standard of plaque control or (ii) the health condition of the peri‐implant mucosa, as determined by bleeding on probing. Hence, the study failed to support the concept that the lack of an attached portion of masticatory mucosa may jeopardize the maintenance of soft tissue health around de

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1994.050101.x

出版商:Munksgaard International Publishers    

年代:1994

数据来源: WILEY

摘要:

Sixty‐six ITI implants placed in the mandible of 33 edentulous elderly patients (mean age: 69 years) were observed longitudinally for 5 years. The implants served as overdenture anchorage either by means of a connecting bar or single spherical attachments. During the study period, 2 implants failed (one because of a peri‐implant lesion and one because of a fracture) and had to be removed. At the beginning of the study, all implants were osseointegrated and had successfully been in function for 335 months. Oral hygiene practices and the peri‐implant mucosal status were assessed according to the criteria of conventional periodontal parameters. Approximately 50% of the implants had been installed into lining mucosa and hence were to surrounded by keratinized mucosa. The peri‐implant mucosal tissue was maintained healthy during the whole observation period, and no or only minimal loss of attachment was observed. The probing depths averaged approximately 3 mm. At the end of the study, orthopantomographic radiographs were obtained from all patients to assess the peri‐implant bony structures. Small local angular bony defects were detected on 16 implants (22%) in 12 patients. Slightly increased probing depths were observed when angular bony defects were present. Loss of attachment was significantly less frequent when the implants had been placed following a prolonged period of edentulousness (<5 years). This study demonstrated that advanced age, reduced dexterity of elderly patients and environmental conditions of overdentures do not represent a 1 higher risk for the development of peri‐impl

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1994.050102.x

出版商:Munksgaard International Publishers    

年代:1994

数据来源: WILEY

摘要:

Removal of plaque and calculus by means of sonic and ultrasonic scalers causes considerable damage to implants. With a view to avoiding the aggressive effects of these instruments, an experimental study was carried out for which conventional sonic and ultrasonic scalers were coated with Teflon®. The effects of these instruments on implant surfaces was then compared with that of plastic and metal implant curettes. Stereo‐microscopy, scanning electron microscopy and surface profilometry were used to detect and record damage to implant surfaces and changes in surface roughness. Generation and propagation of heat in subgingival simulation of use of sonic and ultrasonic scalers were also recorded by means of temperature measurements at the implant surface. The results revealed that no discernible damage was caused by Teflon‐coated sonic and ultrasonic scalers or implant curettes made of plastic on smooth titanium surfaces. Instrument material residues were found on rough implant surfaces. It was not the intention of this study to provide an analysis of the prerequisites for the cleaning of rough implant surfaces. but rather to determine what type of damage is to be expected when contact is made with smooth and rough surfaces unintentionally. Temperature measurements during the subgingival use of sonic and ultrasonic scalers indicated satisfactory functioning of the cooling system. Coating of sonic and ultrasonic scaler tips with Teflon thus facilitates the use of high‐frequency instruments to achieve professional cleaning of im

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1994.050103.x

出版商:Munksgaard International Publishers    

年代:1994

数据来源: WILEY

摘要:

A photogrammetric technique was designed to measure the position of dental implants in 3 dimensions to enable assessment of the tit of superstructures placed on the implants. A relatively simple camera setup was developed and tested. Calibration of the camera was performed in a high‐precision analytical plotter and revealed a film measurement accuracy of 0.005 mm. The achieved measuring accuracy for clear and well defined points on clinical components was found to be around 0.02 mm. To find the center points of the implants, points on the circumference were measured. These points are not well defined, which resulted in an estimation of the center point of the implant with a precision of 0.05 mm. Independent measurements of a prosthesis with 5 implants were also within the precision of 0.05 mm. The angular orientation of the top surface of the implant cylinder (abutment, brass replica of gold alloy cylinder of the framework) was measured with a precision of 0.01 radians, which corresponded to an error with a peripheral gap of about 0.03 mm. This value was about 5‐10 times lower than the clinical fit between frameworks and abutments, measured in 3 randomly selected clinical ca

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1994.050104.x

出版商:Munksgaard International Publishers    

年代:1994

数据来源: WILEY

摘要:

The aims of this study were a) to assess in an in vitro model the amount of density changes measured in digitally subtracted images due to electronic noise and image alignment error, and b) to test the accuracy of different gray level correction procedures in the reduction of densitometric image mismatches. A section of a pig mandible in which a hollow cylinder ITI Bonefit® implant had been placed was used to obtain pairs of standardized radiographs. Series of radiographs were obtained with different exposure times (0.34, 0.39, 0.44, 0.51, 0.58 s). The radiographs were captured through a video camera, digitized and stored in a personal computer. The same radiographic image was recorded and subtracted from itself 10 times to study the error of the method due to electronic transformations of the images and image alignment. The noise due to the analog‐to‐digital transformation of the radiographic images was calculated to be +2 gray levels i.e., 2% of the scale of gray levels. This kind of error was reduced up to 40% by capturing the images more than once and averaging the values per pixel. The manual superimposition of the images to be subtracted caused an increase of the error to ±3 gray levels (2.7%). Seven methods of gray level correction based either on a linear least squares approximation or on the cumulative density function (CDF) were tested. The group based on the CDF algorithm gave significantly better results than any other method. Pixels yielding differences smaller or equal ±7 gray levels (5.5% of the scale of gray levels) should be excluded from further calculations in order to eliminate (false‐positive) errors due to the normalizing algorithms. Furthermore, the CDF method on an arbitrarily chosen area of the image or on the wedge seems to give to subtraction images the ability of revealing real subtle changes in tissue density (fewer false‐negative errors). The use of reference structures did not futher improve the ability of the normalization methods to correct gray level mismatches between radiogra

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1994.050105.x

出版商:Munksgaard International Publishers    

年代:1994

数据来源: WILEY

摘要:

A single tooth implant was placed in a boy aged 12 years and 3 months. The case has been followed for more than 4.5 years. The fixture did not move together with the adjacent teeth as the maxillary growth went on. There was no “loss” of marginal bone on the side of one adjacent tooth where the distance between implant and tooth was appropriate. But a “loss” of marginal bone (measured from the cemento‐enamel junction) was noted on the other adjacent tooth where the fixture had been placed 1 too close to

ISSN:0905-7161    

DOI:10.1034/j.1600-0501.1994.050106.x

出版商:Munksgaard International Publishers    

年代:1994

数据来源: WILEY