The aim of the study was to evaluate the precision of a reflectance spectrophotometer during longitudinal assessment of tooth colour in vivo. The spectrophotometric data of five standardized circular areas on the labial surfaces of six teeth (four upper and two lower), from 22 dental students, were recorded on three separate days (1st, 3rd and 30th) employing a repeated-measuring design (n = 3). Total colour differences were calculated according to the equation DeltaEpsilon = [(DeltaL*)(2) + (Deltaa*)(2) + (Deltab*)(2)](1/2). It was found that all measured teeth areas, recorded by the same examiner (DeltaEpsilon(INTRA)), demonstrated minor colour changes during the three different time intervals, which did not exceed in every case the 50:50% perceptibility threshold of DeltaEpsilon = 1, thus indicating a good match. The smallest DeltaEpsilon values were recorded for the upper central incisors, whereas lower central incisors and upper first premolars revealed the most significant colour differences (0.68 +/- 0.21 and 0.70 +/- 0.25 DeltaEpsilon-units, respectively). The central zone of the middle third of each labial tooth surface exhibited the most precise recordings. With regard to interexaminer reproducibility (DeltaEpsilon(INTER)), the mesial and distal areas of all measured teeth presented the most statistically significant colour differences (0.48 +/- 0.15 and 0.50 +/- 0.17 DeltaEpsilon-units, respectively). It is concluded that the spectrophotometer tested in the present study can provide a precise measurement of tooth colour in vivo. However, in rejection of the null hypothesis, the type (posterior teeth, mandibular incisors) and the mesial and distal areas of natural teeth affected the repeatability and reproducibility of intraoral spectrophotometric measurements.
The aim of this study was to evaluate the dentoskeletal relationships in children with juvenile idiopathic arthritis (JIA) compared to healthy children without significant differences in relation to age and sex, by means of lateral cephalometric radiographs. Cephalometric, as well as dental panoramic radiographs were taken of 66 JIA children (27 males and 39 females; age range: 6-19 years; mean age: 11.9 years). The control group consisted of 37 healthy children unaffected by JIA seeking orthodontic treatment, with Class I occlusion (17 males and 20 females; age range: 7.5-17 years; mean age: 11.9 years). All cephalometric landmarks were identified and digitized, and calculations were performed by means of a computerized cephalometric system. The cephalometric findings indicated a tendency towards retrognathism with a short mandible. The lower facial height was increased and the growth pattern of the face was biased towards the vertical direction (clockwise, i.e. with a tendency to open bite) and the interincisal angle was less in the JIA children compared to the healthy children. These findings were in general more pronounced by the JIA children with polyarticular type of the disease as well as with affected condyles. Our study indicated that the dentoskeletal morphology in children with JIA presented some special characteristics when compared to healthy children, which could be attributed to the effects of the disease.
Children with juvenile idiopathic arthritis presented a remarkable prevalence of condylar destruction, which was correlated to the type and duration of the disease.
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