Objective: To evaluate dimensions of the nasopalatine canal and the relationship between the canal and the central incisors, and the canal and the crest, by using cone-beam computed tomography ( CBCT) . Methods:This study included 129 CBCTs, and the sagittal slices were used to measure the lower diameter ( Sda) , median diameter ( Sdb) , and higher diameter ( Sdc) , for calculating the average sagittal diameter ( Sd ); the coronal slices through canals were used to measure the lower diameter ( Hda) , median diameter ( Hdb ) , and higher diameter ( Hdc ) for calculating the average horizontal diameter ( Hd) , length ( H);the sagittal slices were used to measure the buccal bone thickness off the canal ( Bt) , and the distance to the crest off the lowest point ( At) , the horizontal slices were used to measure the distance between the canal and the central incisors ( Id) . These subjects were divided into two groups by gender;and divided into three groups by ages: (1) ≤30 years old, (2) 31 -50 years old, and (3) ≥51 years old. SPSS 17. 0 statistical software was used for statistical analysis. Results:The overall Sd was (3. 41 ± 0. 87) mm, the Hd was (5. 16 ± 0. 93) mm, and the difference was statisti-cally significant. The H was (14. 29 ± 3. 27) mm, the Bt was (7. 49 ± 1. 05) mm, the At was (8. 25 ± 1. 71) mm, and the Id was (2. 71 ± 0. 89) mm. Of the male and female, the Sd were (3. 64 ± 0. 90) mm and (3. 28 ± 0. 82) mm, P=0. 017; the Hd were (4. 98 ± 0. 89) mm and (5. 27 ± 0. 94) mm, P=0. 081;the H were (15. 47 ± 2. 75) mm and (13. 59 ± 3. 32) mm, P=0. 001;the Bt were (7. 90 ± 0. 96) mm and (7. 25 ± 1. 03) mm, P=0. 001; the At were (7. 41 ± 1. 86) mm and (8. 44 ± 1. 90) mm, P=0. 001; the Id were (2. 71 ± 0. 87) mm and (2. 72 ± 0. 91) mm, P =0. 983. Among the groups, no statistically significant differences were detected of the Sd (P =0. 325), of the Hd (P =0 . 636 ) , of the H ( P=0 . 292 ) , and of the Bt ( P=0 . 116 );statistically significant differences were de-tected of the At ( P=0 . 010 ) , and of the Id ( P<0 . 001 ) . Conclusion:The nasopalatine canal anatomy is highly variable. Gender is related to the nasopalatine canal length, Bt width, and At distance. While age was related to At, and Id, but no effect on nasopalatine dimensions. The CBCT is a useful device for studying the nasopalatine canal in three dimensions, prior to dental implant placement.

Objective: To measure the distances among anatomic points of bony orbit of Chinese Han-nationality adults. Methods: Bony orbits were measured with the special measuring tools in 86 Chinese adults (62 males and 24 famales), and the results were statistically analysed. Results: Difference between the left and right obits was observed in orbital width, medial distance of superior orbital foramen a and inferior foramen a and c in males. Difference between bilateral orbits was also observed in orbital width and anterior distance of superior orbital fissure in females. Normal values of the distances of anatomic points of adult orbits were then calculated. Conclusion: Normal values of the distances of anatomic points of orbit of male and female adults are concluded.

Objective: To compare the peri-implant tissue stability between immediate implant and delayed implant in maxillary anterior region after loading 2 years.Methods: In the study, 38 patients with single anterior tooth loss in the Second Clinical Division of Peking University School and Hospital of Stomatology from October 2010 to December 2011 were enrolled , and 43 implants were inserted .The gin-gival contour was induced using implant-supported temporary crowns prior to restoration till permanent prostheses delivered .The gingival papilla height , labial gingival margin level and peri-implant bone level were measured immediately after the permanent restoration and 2 years later .Results: In the study , 16 patients were treated by immediate implant for 17 implants;22 patients were treated by delayed im-plant for 26 implants .The implant stability quotient ( ISQ ) value of the 2 groups showed no significant difference before permanent restoration (P>0.05).In all the cases after loading 2 years, the average mesial gingival papilla height in the implant area of the immediate group and delayed group increased by (0.15 ±0.42) mm and (0.06 ±0.65) mm, respectively;the distal gingival papilla height increased by (0.06 ±0.50) mm and (0.02 ±0.57) mm respectively;while the labial gingival margin level shrinka-ges were (0.15 ±0.23) mm and (0.15 ±0.46) mm, respectively.The peri-implant bone losses in the mesial side were (0.67 ±0.35) mm and (0.69 ±0.49) mm, respectively, while in the distal side were (0.73 ±0.31) mm and (0.75 ±0.48) mm, respectively.All these indicators showed no significant difference between the 2 groups ( P>0 .05 ) .Conclusion:Both the cases obtained optimizer results after loading 2 years, and the soft and hard tissues around the implant were very stable , which means that both the protocols can achieve reliable therapeutic effects .If we can handle the indications , immediate implant for anterior teeth shows similar efficacy with delayed implant in the short term .But immediate implant in terms of shortening the course of treatment is clearly superior to delayed implant .

Cone beam CT(CBCT)data of 4 550 impacted mandibular third molars were divided into 6 groups by the direction of teeth im-paction.Analyzed by SPSS 19.0 statistical package and Pearson Chi-square Test,the incidence of disto-lingual roots was 5.38% and was various with different impation direction.

In order to obtain comprehensive brain activity information conveniently in real time, this study designs a portable EEG and blood oxygen synchronous acquisition system for real-time monitoring of brain functional activities. The EEG electrodes filter and amplify the detected EEG signals, and send them to the microprocessor via Bluetooth to analyze the EEG data; the photoelectric probe converts the optical signals into electrical signals, which are amplified and separated, filtered, and AD converted, calculates the brain's oxygenation and blood-red protein (ΔHbO
Brain ; Electrodes ; Electroencephalography ; Oxygen

Objective: To assess clinical and radiographic outcomes of short implants (length six mm) in the posterior region and early-loading with splinted fixed dental prostheses. Methods: Forty-five patients were recruited at 3 centers and 2-3 implants (diameter 4 mm, length 6 mm) were implanted in each case. Totally, ninty-five implants were placed, using one-stage surgery protocol and loaded with a screw-retained splinted fixed prosthesis 6 weeks later. Clinical and radiographic examinations were performed preoperatively, post-surgery, at loading, and 6, 12 and 24 months after prosthesis placement. Results: Four implants were removed before loading. A total of 36 patients with 76 implants completed the whole treatment and 2 year follow-up according to the research design. No implant was lost after loading, and the 2-year survival rate of the implant was 100%(76/76). In all cases, the response of swelling and pain after operation was mild, and the bone resorption around the implants was not obvious at 6 months [(0.04±0.29) mm], 1 year [(-0.11±0.44) mm], and 2 years [(0.00±0.53) mm] after loading. Bone loss less than 1.00 mm was found only in 26% (18/69) implants after 2 years of loading, and the height of the alveolar bone around 17% (12/69) of the implant increased. During 2-year follow-up, the probing depth of the implants increased by nearly 0.50 mm, but there was no clinical significance (P>0.05). Conclusions The 2-year results of this study showed that the 6-mm-long implants can be a predictable procedure, especially in situations with limited bone height in posterior edentulous regions.