Methodology of three‐dimensional determination of root surface roughness

Abstract

In comparing and evaluating the instruments that are used in root debridement, roughness constitutes a standard variable that is assessed. The purpose of this study was to describe the conditions and requirements for the three-dimensional roughness measurements of tooth roots using a laser profilometer. Impressions were made of 60 instrumented and 12 untreated root surfaces, which were then measured using a dynamically focussing optical profilometer (Mikrofocus, UBM, Karlsruhe, Germany). To separate roughness from the form of the tooth, a low pass filter was applied. This meant that the longer wavelengths - which roughly approximated the root forms - were subtracted from the measured profile. We then used an individualized Fourier transformation to define the threshold at which roughness becomes waviness. Roughness parameters were Ra (average roughness) and Rz (average roughness in the z dimension) for two- and three-dimensional measurements. To describe the requirements for the measurement, we studied the effect of pixel density and the field size on the average roughness value, Ra. We found that Ra increases with pixel density until 400 per mm is reached, after which it does not change meaningfully. Furthermore, Ra is highly dependent upon the area of the field to be scanned, increasing in line with the area, and does not approach one value within the surface available on one tooth. The correlation coefficients between the two-dimensional and three-dimensional Ra and Rz values ranged from 0.7 to 0.8. We conclude that roughness values are strongly dependent on the measurement conditions and the results of one study cannot be directly compared to another. In addition, it was found that two-dimensional measurements are sufficient for characterizing root surfaces.

Study on the relationship between damage of oil‐impregnated insulation paper and evolution of phase‐resolved partial discharge patterns

“…During the damaging process of oil-impregnated insulation paper, the microstructure of the surfaces of the insulation paper in different damaging stages was studied using an atomic force microscope (AFM.IPC-208B), and the three-dimensional roughness was calculated [26,27]. For more efficient representation, the surfaces of the insulation paper were divided into three ring-zones, namely, the internal, medium, and external rings.…”

A comparison of magnetostrictive and piezoelectric ultrasonic scaling devices: an in vitro study

“…On the other hand, Busslinger et al [9] reported that a piezoelectric device left a rougher surface than a magnetostrictive device after instrumentation. The roughness of the root surface after a scaling procedure is a factor to consider for maintenance because it has also been reported that bacterial plaque adheres easily to the rough root surfaces after treatment [10,11]. A comparison of different piezoelectric or magnetostrictive ultrasonic devices can be expected to produce differences in tooth surface roughness.…”

Root surface defect produced by hand instruments and ultrasonic scaler with different power settings: an in vitro study

“…Currently, the use of the ultrasonic scaler has appeared as an important alternative for daily clinical use due to its several advantages, such as access to furcation, less operator tiredness, pocket penetration and less time required for scaling and root planning (1,2). Studies evaluating differences in the magnitude of root surface alterations produced by hand, sonic, and ultrasonic instruments are inconclusive (1)(2)(3). Considering manual and ultrasonic scalers, some reports indicate that manual scalers remove more root substance (4), whereas others found that ultrasonic scalers do so (2).…”

“…The RLTSI evaluates roughness and substance loss concomitantly. However, the loss of tooth substance with the use of a specific instrument cannot be directly correlated with the roughness produced on root surface (3,9), needing a separate evaluation (9).…”