Three-dimensional survey of the whole mandibular canal and mandibular morphology by cone beam computed tomography in normal young people / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This research aimed to analyze the three-dimensional position of mandibular canal (MC) and man of MC and its relationship with the surrounding structures dibular morphology of normal young males and females by using data from cone beam computed tomography (CBCT), as well as to provide an anatomical basis for clinical surgery of the mandible.</p><p><b>METHODS</b>Normal occlusion and CBCT scans of 29 normal young people were conducted. InVivo 5 software was used to reconstruct the mandible, anchor the points, and measure the jaw shape and three-dimensional course of MC. All measurements were analyzed with SSPS 17.0 software.</p><p><b>RESULTS</b>The MC lingual bone cortex was thinner than the MC buccal bone cortex, and the distance of the MC to the buccal bone cortex gradually increased. However, the distance of the MC to the tongue bone cortex and alveolar crest gradually decreased from proximal to distal. In addition, the distance of the MC to the mandibular lower margin was minimal at the first molar and reached the maximum at the second premolar. No significant difference was observed among the heights, widths, and thicknesses of the left and right sides of the cortical bone of the mandibular body cross sections. From the midline to the farthest point, the height and lower one-third thickness of the lingual cortical bone of the mandibular body cross sections gradually decreased, whereas the width of the upper cross section and upper one-third thickness of the buccal cortical bone gradually increased. Significant difference was observed in some measured values.</p><p><b>CONCLUSION</b>After MC enter into the mandibular foramen, it moved away from the lingual to the buccal bone but gradually returned to the lingual bone; its general course is closer to the lingual bone. The mandibles of males are thicker than those of females. CBCT can accurately display the course of MC and its relationship with the surrounding structures.</p>

Application of 3D printing technique in bilateral sagittal split osteotomy / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the application of osteotomy template manufactured via 3D printing technique in bilateral sagittal split osteotomy (BSSO).</p><p><b>METHODS</b>The patient group consisted of 32 patients (17 males and 15 females) with mandibular hypoplasia who underwent a BSSO setback (Hunsuck modification; 64 splits). The mean age at the time of surgery was 23.5 years (range 1.9-35 years). All patients were scanned using cone beam computed tomography (CBCT) to create a 3D model of the mandibular, and the osteotomy template of the inner horizontal ramus of mandible bone incision was manufactured via 3D printing technique. All splits underwent operation with or without the osteotomy template by either a young doctor (attending doctor) or a doctor with extensive orthognathic surgery experience (chief doctor). The time it took to perform the mandible bone incision of the inner horizontal ramus of each group was recorded. Postoperative CBCT scan was performed, and the lingual split scale was used to assess the effect of the operation.</p><p><b>RESULTS</b>Primary healing of incisions was observed in all patients, and no serious complications occurred. The time it took to perform the mandible bone incision of the inner horizontal ramus was significantly different in the four groups (F=30.059, P<0.05), and it was longer in the group of the attending doctor without osteotomy template than in the other three groups (P<0.05). No significant difference was observed in the other groups (P>0.05). Although all splits (n=64) were performed according to the standardized protocol, only 59.38% (38/64) of the fracture lines run according to the Hunsuck's description. By contrast, only 21.88% (14/64) run through the mandibular canal and 18.75% (12/64) was split. The database was analyzed using crosstabs and via Fisher exact test. The split pattern was influenced by the application of an osteotomy template (P<0.05).</p><p><b>CONCLUSION</b>The application of osteotomy template manufactured via 3D printing technique in BSSO was effective, which enabled the young doctor to complete the operation faster and with good results.</p>

Application of PBL in pathogen biology and immunology teaching at college level / 中华医学教育探索杂志

Objective To explore the practice effect of problem-based learning(PBL) in teaching of pathogen biology and immunology at college level.Methods Three-year clinical majors of class 1 and 2 in Luohe Medical College were chose,class 1 as PBL experimental group(n=100) and class 2 as control group(n=100).Chapter of hepatitis virus was taught respectively using PBL and LBL teaching method.Teaching effect was evaluated by test and questionnaire.Teaching effects between PBL and LBL were compared.SPSS 13.0 was used to do statistical analysis and data were expressed as percentage.Chi-square test was performed and P＜0.05 shows statistically significant differences.Results Results of test showed that excellent and passing rates were higher in PBL group than in LBL group(P=0.000) ; flunked rate was lower in PBL group than in LBL group(P=0.000).Results of questionnaire showed that more than 80％ students thought that PBL can mobilize students' initiatives of learning,train cooperation consciousness and enhance language skills,etc.Conclusions PBL can be used in pathogen biology and immunology for 3-year clinical majors and deserves further application.

Dynamic change of parasites in the brains of BALB/c mice infected with Angiostrongylus cantonensis / 中国人兽共患病学报

To observe the dynamic change of parasites in the brains of BALB/c mice infected with Angiostrongylus cantonensis in order to explore its possible mechanism of pathogenesis', BALB/c mice infected with the III stage larvae of A.cantonensis were observed and killed in different times after infection. The number and distribution of parasites in the brains of the infected mice were observed microscopically and macroscopically. It was found that the larvae of A.cantonensis were distributed in the cerebrum and cerebellum of mice in accordance with the rule of parasitization of worms in the host, i.e.multiplication at first and then dropping in number. And the places where the parasites located were damaged due to mechanical action or inflammatory reactions. The time of onset of symptoms, such as ataxia and twitch was coincided with the dynamic changes in the brains of the infected mice.