Multilayer Architectures for Facial Action Unit Recognition.

In expression recognition and many other computer vision applications, the recognition performance is greatly improved by adding a layer of nonlinear texture filters between the raw input pixels and the classifier. The function of this layer is typically known as feature extraction. Popular filter types for this layer are Gabor energy filters (GEFs) and local binary patterns (LBPs). Recent work [1] suggests that adding a second layer of nonlinear filters on top of the first layer may be beneficial. However, it is unclear what is the best architecture of layers and selection of filters. In this paper, we present a thorough empirical analysis of the performance of single-layer and dual-layer texture-based approaches for action unit recognition. For the single hidden layer case, GEFs perform consistently better than LBPs, which may be due to their robustness to jitter and illumination noise as well as to their ability to encode texture at multiple resolutions. For dual-layer case, we confirm that, while small, the benefit of adding this second layer is reliable and consistent across data sets. Interestingly for this second layer, LBPs appear to perform better than GEFs.

The bond strength of an adhesive resin luting cement to a variety of surface treatments of a high-palladium copper alloy.

PURPOSE: This study evaluated the tensile bond strength of a bisphenol glycidyl methacrylate (Bis-GMA) resin luting cement with four different surface treatments of a high Pd-Cu alloy. MATERIALS AND METHODS: For each surface treatment type (tin-plated, porcelain furnace oxide, air-abraded, and finished-only), 15 opposing half-dumbbell-shaped samples were cast and prepared in new Pd-Cu alloy. Samples were luted with a Bis-GMA resin luting cement at a film thickness of 80 microns using a custom alignment apparatus. Samples were stored in distilled water at 37 degrees C for 24 hours, thermocycled for 1,000 cycles, and then stored for 30 days in distilled water at 37 degrees C. Samples were then subjected to fracture in tension at a loading rate of 0.5 cm/min with the bond strengths calculated in megapascals (MPa). The fractured surfaces were examined using stereomicroscopy and scanning electron microscopy at various magnifications ranging from 5.5x to 500x to determine the type of bond failure (adhesive, cohesive, or mixed). RESULTS: Tensile bond strengths (mean +/- SD MPa) were: tin-plated, 30 +/- 15.7; porcelain furnace oxide, 23 +/-n 8.6; air-abraded, 8 +/- 8.1; and finished-only, 4 +/- 4.5. Statistical analysis of the tensile bond values using an ANCOVA and Tukey's multiple comparison test at a significance level of 0.05 indicated that there was no difference between the tin-plated and the furnace oxide groups, as well as between the air-abraded and the furnace oxide groups. However, there was significant difference between the tin-plated, the air-abraded, and the finished-only groups. The observed bond failures were predominantly mixed and cohesive in nature with only one adhesive failure. CONCLUSIONS: There was no significant difference in the tensile bond strengths between the tin-plated group or the porcelain furnace oxide surface group. This suggests that the less-technique-sensitive porcelain furnace oxide surface treatment offers an alternative for achieving high metal-resin bonds to a high Pd-Cu alloy.

Dimensional stability of two visible light-cured indirect inlay/onlay resin composite materials.

PURPOSE: To evaluate the dimensional stability over time of two visible light-cured indirect inlay/onlay resin composites. MATERIALS AND METHODS: Twenty working dies of a Class II preparation were constructed in type IV die stone from impressions of a master metal die. Working dies were randomly divided into two groups of 10 with Class II resin composite inlays fabricated using Brilliant Dentin (n = 10) and Triad inlay material (n = 10). Inlays were seated on the master metal die 1, 3 and 10 days after fabrication and resin replicas were made of the proximal gingival margin surface which were gold-sputtered and used for the measurement of gingival margin gap distances at four locations using an SEM micron measurement system. RESULTS: Triad inlays mean gingival margin gap measurement was significantly (P < 0.05) greater at 10 days versus 1 day. Brilliant Dentin inlays had no significant mean gingival margin gap measurement differences between any time periods. As a material, Triad inlays had significantly less gingival margin gap distances than the Brilliant Dentin inlays at all three time intervals.

Pain assessment in temporomandibular disorders.

Pain characteristics, symptoms, medication use, demographic and psychological variables were assessed in 85 patients diagnosed with temporomandibular (TM) disorders. Results showed that 46 myofascial pain dysfunction (MPD) patients responded differently from 39 temporomandibular joint (TMJ) patients for numerous measures of pain-related variables. MPD patients perceived more generalized facial pain of longer duration and were able to identify more specific symptoms associated with their pain. The only symptom variable rated higher by TMJ patients was the presence of bothersome joint noise. When asked to rate their pain at its worse, the unpleasantness of pain was significantly higher in MPD patients than reported by TMJ patients. MPD patients might be considered more psychologically distressed than TMJ patients, as shown by their higher ratings for anxiety and inability to endure the pain. Although both types of pain patients took the same categories of medications, MPD patients consumed a larger total number. Such findings suggest that the prognosis of the dysfunction for MPD patients would be less favorable than for TMJ patients.

The prevalence of oral mucosal lesions in an elderly population.

In a population of 629, 145 elderly subjects had at least one mucosal lesion; 27% of denture wearers had a denture-related lesion. Lesions were found most commonly on the palate, followed by the lips. Increasing age was the only significant factor in the risk of soft tissue enlargement.