Resampling-Detection-Network-Based Robust Image Watermarking against Scaling and Cutting.

Watermarking is an excellent solution to protect multimedia privacy but will be damaged by attacks such as noise adding, image filtering, compression, and especially scaling and cutting. In this paper, we propose a watermarking scheme to embed the watermark in the DWT-DCT composite transform coefficients, which is robust against normal image processing operations and geometric attacks. To make our scheme robust to scaling operations, a resampling detection network is trained to detect the scaling factor and then rescale the scaling-attacked image before watermark detection. To make our scheme robust to cutting operations, a template watermark is embedded in the Y channel to locate the cutting position. Experiments for various low- and high-resolution images reveal that our scheme has excellent performance in terms of imperceptibility and robustness.

[Application of comfort care for dental out-patients].

OBJECTIVE: To explore and apply the nursing methods of comfort care for dental out-patients. METHODS: Control group included 103 dental out-patients who were first treated in General Dentistry Department of West China Hospital of Stomatology from June to August 2008. Experimental group included 105 dental out-patients who were first treated in the same hospital from September to November 2008. Conventional nursing methods were used for control group, and comfort care nursing methods were used for experimental group. The patients' degree of satisfaction with nursing and oral health knowledge rate after first treatment and nursing were investigated. RESULTS: The patients' degree of satisfaction with nursing of the control and experimental groups were 72.816% and 98.095%, and the patients' oral health knowledge rate of the two groups were 57.282% and 93.333%. Both of the investigating results had obvious difference. CONCLUSION: Comfort care for dental out-patients can improve patients' degree of satisfaction with nursing and increase patients' oral health knowledge rate. Simultaneously, comfort care can improve the specialized quality of dental nurses and would advantage to build a harmonious relationship between nurses and patients.

[Influence of hand-mixed methods on compressive strength of zinc phosphate dental cement].

OBJECTIVE: To study the influence of hand-mixed methods on the compressive strength of the zinc phosphate dental cement. METHODS: Three skilled nurses used three kinds of common clinical hand-mixed methods (included the unidirectional rotation method, the alternate pro and con bidirectional rotation method and the pulling and pushing with folding method) to mix the zinc phosphate dental cement on the same condition (i.e. same indoor temperature and humidity, the same mixing ratio, mixing time, mixing frequency and the same mixing instruments and so on). The mixed zinc phosphate cement was packed into the plastic cylinders with 10 mm-high and 5 mm-bore. After the mixed zinc phosphate cement coagulated, compressive strength was tested separately. RESULTS: The compressive strength of the zinc phosphate dental cement mixed with the alternate pro and con bidirectional rotation method was the best, and the value was (106.11+/- 4.82) MPa. The compressive strength of the zinc phosphate dental cement mixed with the pulling and pushing with folding method was lower, and the value was (77.57 +/- 6.26) MPa. The compressive strength of the zinc phosphate dental cement mixed with the unidirectional rotation method was the lowest, and the value was (54.41 +/- 5.08) MPa. The compressive strength of the zinc phosphate dental cement mixed with the unidirectional rotation method and the pulling and pushing with folding method could not achieve the clinical required compressive strength (about 100 MPa), while the compressive strength mixed with the alternate pro and con bidirectional rotation method was above 100 MPa. CONCLUSION: The alternate pro and con bidirectional rotation method to mix the zinc phosphate dental cement is recommended in clinic.

[Effect of root canal curvature on canal length measurement on digital image of human lower mandibular permanent incisor].

OBJECTIVE: To investigate the effect of canal curvature on measured precision in canal length of human lower mandibular permanent incisors imaged by direct digital radiograph. METHODS: With Trophy digital X-ray system, 299 Chinese lower mandibular permanent incisors were selected to take the direct digital X-ray photography in both facial to lingual (L-T) and proximal directions (M-D). Two operators familiar with endodontic knowledge estimated the canal length by means of on-screen DDR with 2-and 3-click measurements. RESULTS: The true canal length of Chinese lower mandibular permanent incisors was (19. 54 +/- 1.62) mm. The tooth root canal length on digital image was overestimated with 3-click measurement (P < 0.05), and the canal length with 2-click measurement was almost similar to the true canal length from the facial-lingual direction X-ray photography (P > 0.05). The less than 1 mm difference between the estimated canal and the true canal length was above 95%. The canal length was underestimated with 2-click measurement as the curvature severity increased. CONCLUSION: Direct digital radiography system is applicable to estimate the canal length in clinic as the accuracy is very good. The curved canal length should be estimated with 3-click measurement.

[Comparative study of shaping ability between rotary ProTaper and Flexofile].

OBJECTIVE: To compare the shaping ability of rotary ProTaper and Flexofile in simulated resin root canals. METHODS: Forty simulated resin root canals were randomly assigned to two groups, one group for rotary ProTaper with crown-down technique and the other for Flexofile with balanced force technique. Change of working length and incidence of canal aberration and instruments failure were recorded. After preparation, the change of root canal curvature and the amount of resin removed at the inner and outer canal walls were measured with Image Pro Plus 5.0. The centring ability and total amount of resin removed were also assessed. RESULTS: In the model of simulated resin canals, ProTaper instruments maintained working length better. Canals prepared with ProTaper instruments remained better curvature and showed fewer aberration compared with those prepared with Flexofile (P < 0.01). ProTaper instruments performed a better centring ability. CONCLUSION: ProTaper instruments have a better shaping ability in simulated resin root canals.

[Nursing of canal obturation during root canal therapy].

OBJECTIVE: To explore the nursing methods during canal obturation in order to improve efficiency and quality of root canal therapy. METHODS: 112 teeth treated by complete root canal preparation were chosen to fill the root canal, and the main points of nursing during canal obturation were summarized. RESULTS: All of 112 teeth nursed strictly during canal obturation obtained satisfactory efficiency. No one failed after root canal therapy. CONCLUSION: The main points of nursing during canal obturation are the aseptic technique, skilled coordination, instrument management, communication between nurses and patients.

[Nursing experience of acquired immune deficiency syndrome patients in oral outpatient-department].

OBJECTIVE: To explore the main point of nursing acquired immune deficiency syndrome (AIDS) patients with oral lesions. METHODS: To analyze and to summarize nursing experience through 2 patients suffering from AIDS with oral lesions. RESULTS: 2 AIDS patients changed for the better through disinfection isolation, oral nursing, psychology nursing and education propaganda. CONCLUSION: The standard nursing skills is important to AIDS patients, doctors and nurses.

[Use of calcium sulfate as internal matrix to repair furcal perforations].

OBJECTIVE: To evaluate the effect of internal matrix on sealing ability and furcal appearance of perforations repair with amalgam and resin. METHODS: Perforations created in the pulpal floor of human extracted molars were repaired as follows: Amalgam, amalgam plus calcium sulfate, light-cured resin, and resin plus calcium sulfate (15 teeth/group). The furcal appearance of samples was evaluated under an operating microscope after repair. With the leakage test device, coronal 1 mol/L glucose solution was forced toward the pulpal floor. Leakage was measured by the concentration of leaked glucose in bottom reservoir at 1, 2, 4, 7, 10, 15 and 20 days with enzymatic glucose oxidase method. RESULTS: No significant difference was found between group 1 and group 2 (P > 0.05). Leakage in group 4 was obviously lower than group 3 (P < 0.05) after the 7th day. CONCLUSION: Calcium sulfate significantly improved the sealing effect of resin and provided successful barriers against its overextension.

[Histological evaluation of direct pulp capping with a self-etching adhesive and calcium hydroxide].

OBJECTIVE: To evaluate the beagles' pulp response following direct pulp capping with Clearfil SE BOND (SB). METHODS: 130 sound teeth were used. 120 had their pulps mechanically exposed and were divided in two groups. In group A, teeth were capped with SB. In group B, teeth were capped with calcium hydroxide (CH). The left 10 teeth were used as control. After 7, 30 and 90 days, the teeth were extracted and processed for light microscopical examination. RESULTS: In 7 day observation period, inflammatory reaction in SB group was slighter than that of CH group, but the difference was statistical insignificant. In the 30 day and 90 day observation period, inflammatory reaction was slight in both groups, but specimens with dentin bridge formation was significantly less in SB group than in CH group (P < 0.05). CONCLUSION: SB showed acceptable biocompatibility with pulp, but its ability to induce hard tissue barrier on pulp exposure is weaker than CH.