Reproducibility of a hemi mandible positioning device and a method for measuring alveolar bone loss area in mice.
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The objective of this study was to determine the reproducibility of a positioning device and a method for measuring the area of alveolar bone loss (ABL) in hemi mandibles of mice. Mucoperiosteal flaps were raised in CF1 Mus domesticus mice (n = 10) on the buccal aspects of the left side of the mandibles. Twenty-one days after surgery, the animals were sacrificed, and the mandibles were resected and stained with 1% toluidine blue. Two positioning devices, one for the buccal and the other for lingual aspect, were fabricated to keep the hemi mandibles in a standard position. The reliabilities of the positioning device and the method for measuring ABL area were analyzed using two series of pictures. The photographs were digitized and ABL measured as the exposed root area. Measurements were performed by two blinded examiners using image analysis software. Intra- and inter-examiner reproducibility of the positioning method ranged from -1.5 to +1.33 mm, while intra- and inter-examiner reproducibility of the measurement technique ranged from -3.37 to 14.70. Our results indicate that, due to the small variation observed in ABL area assessment, the positioning device and method for measuring ABL area represent useful techniques for evaluating ABL in mice. (+info)
Quantitative evaluation of lip symmetry in skeletal asymmetry.
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The objective of this study was to investigate whether skeletal mandibular asymmetry associated with unilateral and anterior crossbite will lead to lip asymmetry. The subjects were 26 females, 13 controls and 13 true skeletal asymmetric age-matched patients (24-50 years). The study group was diagnosed as asymmetric according to visual and panoramic radiographic examination and exhibited a unilateral anterior crossbite, an asymmetric mandible, and a deviation of the chin. The control group was visually symmetric and exhibited all forms of tooth malalignment without the presence of a crossbite. Digitized images of the frontal facial photographs of all the subjects, taken in an intercuspal contact position, were analysed for upper and lower lip symmetry pre- and post-orthodontic treatment. The upper and lower lips were subdivided into two quadrants each and the surface area of each quadrant was measured and expressed as a percentage of the total surface area of the relevant lip. The degree of lip asymmetry was obtained by calculating the difference in percentage area between the two quadrants of each lip. In the study group, the lower lip quadrant on the crossbite side was increased pre-treatment (56.85 +/- 1.75 per cent), while the contralateral side was reduced (43.15 +/- 1.75 per cent, P < 0.005), resulting in 13.7 per cent asymmetry. After treatment, the respective lip areas were 52.12 +/- 0.64 and 47.88 +/- 0.64 (P < 0.01) and asymmetry was significantly reduced (4.25 +/- 1.29 per cent). In the control group, the differences between the lower lip quadrant areas (range 48.5-51.5 per cent) were small (less than 3 per cent asymmetry) and did not change post-treatment. The findings demonstrate that in this study group, lower lip symmetry was mainly controlled by the support provided through the dental interarch relationships and less by skeletal factors. (+info)
Negative influence of continuous wave technique on apical sealing of the root canal system with Resilon.
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The aim of this study was to investigate apical microleakage after use of the Resilon system in comparison with gutta-percha. The materials used were 54 mesial roots of mandibular molars with an apical curvature of 20-40 degrees . The root canals were instrumented with the Prosystem GT(R) and obturated with: Group I: Gutta-percha + Sealer by lateral condensation (n = 25); Group II: Gutta-percha + Sealer, complemented by System B and Obtura II (n = 25); Group III: Resilon + System B and Obtura II (n = 25); Group IV: Resilon by lateral condensation (n = 25). After immersion in India ink, the specimens were demineralized and rendered transparent. Apical dye leakage was analyzed with a stereomicroscope and a digital camera connected to a computerized system. All groups showed different degrees of apical dye microleakage. The Kruskal-Wallis test revealed that the largest leakage occurred in Group I (P < 0.05), whereas the other groups presented a similar pattern of microleakage (P > 0.05). Thermoplastification negatively influenced the apical sealing ability of Resilon. Gutta-percha points and conventional sealer yielded the highest values of apical leakage, especially when the lateral condensation technique was used. Regardless of the obturation technique employed, the Resilon system provided the lowest mean values of apical leakage, but did not provide hermetic sealing of the root canal system. (+info)
Ranking dental aesthetics and thresholds of treatment need: a comparison between patients, parents, and dentists.
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The aims of the present study were to compare rankings of dental aesthetics and the threshold at which orthodontic treatment would be sought among patients, parents, and dentists. A prospective cross-sectional study was designed to address these aims. The study sample comprised 100 patients and parents and 23 dental specialists. The patients were equally divided between males and females and their mean age was 14.7 years (standard deviation 2.3 years). The aesthetic component (AC) of the Index of Orthodontic Treatment Need (IOTN) represented impairment of dental aesthetics. The 10 numbered photographs of the AC were cut into equal-sized rectangles and subjects were asked to arrange them from 'the one that looks best' to 'the one that looks worst'. The subjects were then presented with the 10 photographs of AC in sequence and asked to identify the cut-off point between 'teeth that need orthodontic treatment' and 'no treatment'. Statistical analysis was undertaken with a Mann-Whitney test. The results showed that median rankings of dental aesthetics were similar among the three groups (P > 0.05). The median ranking of photographs 1, 2, 3, 4, and 10 were identical to the AC of IOTN. The photographs representing IOTN AC 7 and 8 were allocated the same median rank of 7 and AC 5 and 9 were allocated corresponding median ranks of 6 and 8, respectively. There were no significant differences in median cut-off points for treatment need among the three groups of subjects (P > 0.05), indicating that the mean threshold at which treatment would be sought was AC 4. (+info)
Angles of facial convexity in different skeletal Classes.
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The objective of this study was to investigate whether it is possible to use a lateral (profile) photograph to determine the underlying skeletal Class and which reference points of the angle of convexity are most suitable for this purpose. Profile photographs and lateral cephalographs included in the baseline data for 180 orthodontic patients were retrospectively evaluated. The subjects were assigned to skeletal Classes based on Wits values obtained by radiolographic analysis. The Class I subjects were 58 patients (22 males, 36 females) with an average age of 13.63 +/- 2.1 years, the Class II subjects 60 patients (37 males, 23 females) with an average age of 13.60 +/- 2.6 years, and the Class III subjects 62 patients (28 males, 34 females) with an average age of 11.65 +/- 3.3 years. The angles measured were A'OrB' (=POrA'-POrA'), A'N'B', and the angle of convexity with its variants (N'SnPog', N'A'Pog', TrSnPog', TrA'Pog', Gl'SnPog', and Gl'A'Pog'). These angles were statistically evaluated using a two-sided t-test and linear discriminant analysis. Class II and Class III subjects exhibited highly significant differences (P < 0.001) for all angles. Class I and Class III exhibited highly significant differences (P < 0.001) for almost all angles, and significant differences for A'N'B' (P < 0.05). Class I and Class II differed significantly (P < 0.05) only for some angles (N'SnPog', TrA'Pog', Gl'SnPog', and Gl'A'Pog'). The error within the linear discriminant analysis was smallest for N'SnPog', GlA'Pog', and TrA'Pog' angles. However, the method error according to Dahlberg yielded rather high values for all angles (1.07-1.17 degrees). Discrimination between skeletal Class I and Class III was easier than that between Class I and Class II. One of the reasons may be that the subclasses division I and division II were not distinguished within the Class II subjects. (+info)
Analysis of the soft tissue facial profile by means of angular measurements.
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