[Esthetic restoration for anterior teeth with the hot pressed porcelain laminate veneers].

PURPOSE: To evaluate the esthetic effect of anterior porcelain veneers fabricated with the heat pressed glass ceramic. METHODS: Thirty-two patients, who wanted to receive a aesthetic restorative treatment for 206 anterior teeth were selected. Among them, 20 were for dental fluorosis, 8 were for light tetracycline stained teeth, the other 4 were labial enamel hypoplasia or obvious crack on the surface of enamel. According to the color of adjacent teeth,skin and lips, heat pressed IPS e.max ingots of different color were chosen to mold the restorations. Afterwards, special straining technique was conducted on the marginal ridge and incisor ridge of the veneers after carefully trimmed in the mouth. Restorations were them bonded with Variolink II resin cement. After 7 years of follow-up, a modified USPHS criterion was used to evaluate the esthetic effect. RESULTS: The translucency of veneers was superior. Marginal integrity of the veneers was perfect and it docked well with the marginal terminate line of the abutment. There was no edge coloring after the veneers were used for 7 years, and the veneers produce an excellent chameleon effect by absorbing the color of adjacent teeth and gums, at the same time, veneers could produce a feature of surface morphology of natural enamel after careful carve. In the long-term clinical observation, 5 of the 206 veneers were fractured or fell off. CONCLUSIONS: This porcelain laminate veneers fabricated from the heat pressed IPS e.max Press ingots include the following advantages, such as simple operating procedure, high mechanical strength, very little dental tissue was ground off and nice aesthetic effect. Ultra-thin veneers are especially suitable for aesthetic practice to dental fluorosis, light tetracycline and natural worn teeth.

[The prefabricated post and composite resin core technique used in restoring residual crown of posterior tooth].

PURPOSE: To investigate the clinical effect of repairing posterior residual crown using titanium alloy post combined with composite resin core technique. METHODS: Twenty-one patients (26 residual crown) with perfect root canal therapy were selected. Modern bonding technique was used to build up the core with titanium alloy post and flow composite resin together for crown restoration. RESULTS: After ten years of clinical observation, only 4 cases among the 21 patients failed in restoration. The rate of success was 85%. X-ray showed that the periapical alveolar bone density was enhanced after restoration. CONCLUSIONS: Standard root canal therapy and effective post-core strengthening can restore the function of the residual crown and retain the tooth.

[Intraocular lens power calculation after corneal refractive surgery].

OBJECTIVES: To investigate the effective method for the calculation of intraocular lens power retrospectively from post-LASIK cases. METHODS: It was a retrospective case series. 40 eyes of 28 patients (14 male and 14 Female) had the Phacoemulsification post-LASIK in HongKong Sanitorium & Hospital; the age ranged from 41.00 to 69.00 years ages, (50.68 +/- 6.56) years. LASIK was done from January, 1997 to April, 2005. Phacoemulsification was done from October, 2000 to September, 2005. RESULTS: Average axial length was (28.06 +/- 1.98) mm (rang from 24.28 to 31.96 mm). The initial refraction power (Spherical Equivalent, SE) before LASIK was from -3.13 to -18.00 D, (-10.44 +/- 3.93) D. K value pre-LASIK was 41.40 to 46.90 D, (43.57 +/- 1.47) D. The best corrected visual acuity (BCVA) preLASIK was 20/20 in 19 eyes, 20/25 in 10 eyes, 20/30 in 7 eyes and 20/40 in 4 eyes. The refraction power of 6 months post-LASIK (SE) was -2.83 to +1.25 D, (-0.32 +/- 0.95) D. The refraction power pre-phaco (SE) was -5.75 to +1.13 D, (-2.35 +/- 2.16) D. The calculated K1 (KpreLASIK-RpostLASIK + RpreLASIK) was 27.60 to 40.70 D, (34.62 +/- 3.56) D. The K from the IOLmaster (K2) was 32.39 to 43.53 D, (38.04 +/- 2.45) D. The target refraction of K1 was -3.69 to 0.61 D, (-1.32 +/- 1.00) D, the target refraction of K2 was -3.67 approximately 3.95 D, (-0.60 +/- 1.84) D. There was significant difference between these two target refraction, (t = -2.40, P = 0.02). The refraction power of post-phaco (> 3 months) was -4.50 to +1.75 D, (-1.10 +/- 1.51) D. The BCVA post-Phaco was 20/20 in 20 eyes, 20/25 in 9 eyes, 20/30 in 5 eyes and 20/40 in 6 eyes. CONCLUSIONS: The formula used in the study for the calculation of intraocular lens power is accurate and effective.

[Design and analysis of spectral recognition system based on neural network].

The technology of spectral recognition is the foundation of qualitative analysis by spectrum. With the technology of pattern recognition developed, the technology of spectral recognition has been a important tool for quick detection in medicine, environment and petrochemical industry etc. Artificial neural network has many good qualities, such as nonlinear mapping, self-adaptive learning, robustness and fault tolerant ability. It is widely applied in signal procesing, knowledge engineering and pattern recognition etc. The present paper takes spectral signal according with Lambert-Beer' law as object, introduces basic pattern recognition theory of artificial neural network in brief, puts forward spectral recognition method based on multiple features and neural network according to spectral recognition need, makes system design and the basic frame of model, and gives an example for explanation.

Activation of NAD(P)H oxidase by lipid hydroperoxides: mechanism of oxidant-mediated smooth muscle cytotoxicity.

Oxidized lipids, such as 13-hydroperoxyoctadecadienoic acid (13-HPODE), have been implicated in the pathogenesis of atherosclerosis. 13-HPODE, a constituent of oxidized low-density lipoproteins, can induce cytotoxicity of vascular smooth muscle cells (SMC), which may facilitate plaque destabilization and/or rupture. 13-HPODE-induced cytotoxicity has been linked to oxidative stress, although the mechanisms by which this occurs are unknown. In the present study, we show that 13-HPODE and 9-HPODE (10-30 microM) increased superoxide (O2*-) production and induced cytotoxicity in SMC. The 13-HPODE-induced increase in O2*- was blocked by transfecting the cells with antisense oligonucleotides against p22phox, suggesting that the O2*- was produced by NAD(P)H oxidase. Similar concentrations of the corresponding HPODE reduction products, 13-hydroxyoctadecadienoic acid (13-HODE) and 9-HODE, neither increased O2*- production nor induced cytotoxicity, while 4-hydroxy nonenal (4-HNE), an unsaturated aldehyde lipid peroxidation product, induced cytotoxicity without increasing O2*- production. Treatment with superoxide dismutase or Tiron to scavenge O2*-, or transfection with p22phox antisense oligonucleotides to inhibit O2*- production, attenuated 13-HPODE-induced cytotoxicity, but not that induced by 4-HNE. These findings suggest that activation of NAD(P)H oxidase, and production of O2*-, play an important role in lipid hydroperoxide-induced smooth muscle cytotoxicity.