The Periotest measures the reaction of the periodontium to a defined percussive force. The percussion is applied to the tooth by an electronically controlled tapping head. Information on structural change is obtained by measurement of both the elastic and viscous characteristics of the periodontium. The latter prevent oscillations of the tooth in the alveolar bone. A value is calculated and is displayed as a "Periotest value". The following research report shows the relation of Periotest values to bone loss. Bone loss was quantitatively determined for 2312 teeth from orthopantomographic radiographs and for 900 teeth exposed to intra-oral films using the standard paralleling technique. A differentiation was made between vertical and horizontal bone loss. Clinical mobility index, pocket depth, gingival recession and papillary hemorrhagic index were also measured. There was a strong association between the Periotest value and bone loss. These results suggest that Periotest evaluation provides an objective indication of the extent of periodontal bone loss.
The Periotest is a new instrument for the diagnosis of periodontal diseases. The Periotest value depends to some extent on tooth mobility, but mainly on the damping characteristics of the periodontium. The Periotest measures the reaction to a reproducible impact applied to the tooth crown.
The use of cleaning instruments on titanium implants may cause undesired surface alterations. In a qualitative and quantitative assessment of these alterations, 5 titanium implant abutments were treated with a steel curet, a prototype pure titanium curet, an air abrasive polishing system, and an ultrasonic system. Custom-made polymer templates, used to secure the curet to a vertical guide bar and a spring scale to maintain a constant instrument pressure, guaranteed a standardized procedure and reproducible results. The ultrasonic and the air abrasive polishing method were also standardized. Evaluation by scanning electron microscopy (SEM) revealed surface alterations for all instruments and systems except the plastic curet, which did not roughen the surface at all. The confocal laser-scanning microscope allows a 3-dimensional reproduction of these surface alterations and their direct measurement. The profilometric tracing was not sensitive enough to register the minor effects caused by the titanium curet and the air abrasive polishing system. Dimensions of the resulting surface microstructure could be determined with the laser-scanning microscope. Since the influence of such surface defects on the peri-implant tissue reaction is unpredictable, the titanium curet and the air abrasive system can only be recommended with restrictions. The steel curet and the ultrasonic system proved to be totally unsuitable for cleaning titanium implants.
Fibroblasts in culture and in vitro have been shown to interact with certain surface morphological phenomena. It was the aim of the present study to determine cellular morphological interactions with surface grooves of subcellular dimensions. The silicon oxide layer of a wafer was photoetched, which resulted in a regular micromorphology with linear rectangular shaped microbars and microgrooves 1, 1.5, and 2 pm in diameter and distance from each other. Human fibroblasts were seeded on the sterile specimen and incubated for 48 h. Fluorescence microscopy of the plates revealed that all the cells were aligned parallel to the etched grooves on the test specimen, whereas on the controls the cells were randomly orientated. It could be demonstrated by scanning electron microscopy that single cells were flattened over the surface and conformed to the silicon microgrooves. This indicates that fibroblasts are orienting during adhesion and conform to the surface microtexture to gain a maximum contact area on the presented surface.
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