Objective: To explore the clinical, radiographic and pathological diagnosis of fibrous dysplasia of bone (FD) and ossifying fibroma (OF) for improving the diagnosis accuracy. Methods: Clinical file records, radiographs and pathological slices of the 25 cases FD and 16 cases OF were analyzed. Results: Ages of patients have no difference(mean 22.56 years in FD and 28.25 years in OF). The ratio of male to female is 1∶1, the later is 5∶3. The maxilla was involved far more often than the mandible (72% and 62.5%, respectively), most common in the posterior region of the maxilla. Radiographically, ossifying fibroma mostly was mixed radiolucent–radiopacity. Fibrous dysplasia mostly appeared as a radiopaque lesion. Although FD often showed immature trabecular bone formation differentiated to mature trabecular bone of OF, there is the same pathological appearance in mature type of FD and OF. Conclusion: It is necessary to differentiate FD and OF by comprehensive study the clinical cases, X rays and pathological slices.

Objective　To observe the age-related changes of bone thickness in implant area and insertion direction of zygomatic implants. Methods　A total of 150 eligible cases chosen randomly were scanned with CBCT system. All the cases were divided into three groups, defined as occlusion established group, adult group and elderly group by age. With 3-dimensional (3D) images processed by SimPlant, simulate classic zygomatic implant installing operatetion, and bone region with implant in was equally divided into three parts. Zygomatic and maxillary thickness was obtained on the four equant points. Angular between installing direction and plane Md, CR and FH were measured. Results　The mean thickness of maxilla and zygoma in implatation region on each equant point in the three age groups was (6.62±0.14)mm, (8.35±0.27)mm, (9.06±0.23)mm respectively, and there were significant differences among the three groups （P<0.05）, while that in dentate and edentulous subgroup was (8.82±1.97)mm、(9.37±1.78)mm respectively with no statistically significant difference. There was significant difference among different age groups in installing direction（P<0.05）.Gender was not a significant factor（P>0.05）. Conclusion　Bone thickness in implatation region increases with age in classic zygomatic implant method, and zygoma could give a sufficient support for implantation.

To evaluate asymmetry of bilateral condyle in different-age-group patients with mandible deviation based on 3D model reconstructed with 3D CT images.Methods A total of thirty-six patients diagnosed with mandibular deviation were included, and they were divided into three groups by age.The first group included twelve children aged 8 to 11 years old in their mixed dentition period; the second group included twelve youngs aged 11 to 16 years old with early permanent dentition; the third group included twelve adults aged 18 to 30 years old. Every person was scanned with 3-dimensional cone-beam computed tomography (CBCT). Craniofacial DICOM data were acquired. Three-dimensional reconstruction and parameter measurement were done to bone tissue with Simplant software. The results were analyzed statistically. Results There were differences in condylar morphology among different-age-group patients. There was no significant difference in condylar morphology on two sides in mixed dentition period. In the young permanent dentition stage, there was difference in condylar height, condylar transverse dimension, mandibular ramus height, and condylar gradient of back bevel between the contralateral side and ipsilateral side. Bilateral condylar morphology changed asymmetrically. There was significant asymmetrical difference of bilateral condylar morphology in adult patients with mandibular deviation. Compared with the ipsilateral side, condylar height, mandibular ramus height, and condylar transverse dimension were larger on the contralateral side while both the inclination and length of the posterior cant of condyle on the contralateral side were smaller. Conclusions Mandibular deviation may lead to asymmetric remodeling in the condyle. From patients in mixed dentition period to adult patients with mandibular deviation, there was a trend from the mandibular shift to the skeleton abnormal development, so patients with mandibular deviation should receive early treatment.

Objective To evaluate the effect of one-wall ferrule with different location and height. Methods 35 mandibular first premolars were divided into seven groups: Group 1 to Group 3: teeth with a 1 mm ferrule only in the buccal, lingual or proximal region; Group 4 to Group 6: teeth with a 2 mm ferrule only in the buccal, lingual or proximal region; and Group 7: teeth with no ferrule. All the teeth were restored with fiber posts, composite cores and full-metal crowns. Each specimen was subjected to an increasing compressive force at 135 degrees from the long axis in a universal testing machine with a crosshead speed of 1.0 mm/min until fracture. Data were recorded and analyzed using One-way and Two-way ANOVA tests. Results The fracture resistance of teeth was significantly affected by the location of ferrule（P＜0.025）, and the mean failure strength of the buccal group was significantly higher than the lingual group（P＜0.025）. Group 4 demonstrated the highest mean failure strength value in all groups, and the value was significantly higher than group 2, group 3, group 5, and group 7（P＜0.025）. The remaining groups showed no statistical significance. All the fracture mode of specimens were repairable. Conclusion The fracture strength was higher when the dentin wall of ferrule was closer to the loading force. Compared with the no ferrule group, to provide a one-wall ferrule with at least 2 mm high on the main loading force side could improve the fracture strength of teeth.

Objective　To explore prevalance of hearing loss and hearing loss characteristics in different frequencies in patients after cleft palate surgery. Methods　50 subjects with repaired cleft palate and 36 subjects with unrepaired cleft palate were recruited to conduct a pure tone assessment binaurally. We observed hearing loss conditions and compared hearing threshold of 100 ears of 50 subjects with repaired cleft palate in different frequencies. Results　Hearing loss was found in 14 subjects (28.00%) of 50 subjects with repaired cleft palate, and 15 subjects (41.67%) of 36 subjects with unrepaired cleft palate. 84.21% ears with abnormal hearing in subjects with repaired cleft palate (16 ears out of 19 ears) had mild and moderate hearing loss. In the 36 postoperative patients with normal hearing ability, 36.11%,16.67% and 11.11% were identified with hearing loss in the frequencies of 250Hz, 500Hz and 6kHz respectively. Conclusion　Mild to moderate hearing loss was found in some subjects with repaired cleft palate. Mild hearing loss in low and high frequencies was also reported among normal hearing subjects. This indicates that factors going against hearing recovery still exsit to patients with repaired cleft palate. Careful attention should be drawn to ear disease of the patients with repaired cleft palate.

Objective To compare bond strengh of 3M Transbond MIP primer＋3 M Transbond PLUS discolor light curing adhesive and GC Ortho LC light-cured resin-reinforced glass ionomer. Methods The study consisted of 80 maxillary premolars which were extracted for orthodontic treatment.The teeth were randomly divided into 8 groups, with 10 specimens in each.The specimens were bonded with brackets with the two bonding systems under the conditions of dryness, water pollution, saliva contamination and blood contamination respecitively. The shear bond strengh of each tooth was done with electronic universal testing machine, and the ARI scores were used to evaluate the residual adhesive on surfaces of teeth in each group under the microscope. Results In the shear bond strength test, comparing the first group with the fifth group, the second group with the sixth group, the third group with the seventh group, P＞0.01,there was no statistically significant difference; comparing the fourth group with the eighth group, P＜0.01, there was statistically significant difference. The results of ARI showed that there was no statistically significant difference in average ARI scores between the two bonding systems under the conditions of dryness, water pollution,and saliva contamination, but under blood contamination, the ARI score of GC Ortho LC decreased significantly. Conclusion Under the conditions of dryness, water pollution, and saliva contamination, the shear bond strength of 3M Transbond MIP primer＋3 M Transbond PLUS discolor light curing adhesive and GC Ortho LC show no significant difference, but under blood contamination, we recommend using 3M Transbond MIP primer＋3 M Transbond PLUS discolor light curing adhesive.

Objective To observe the growth characteristics of clpP mutant strains of Streptococcus mutants and to compare the growth difference of standard strains and clpP mutant strains under oxidative stress. Methods The standard strains and mutant strains were cultured respectively in TPY medium and TPY medium containing H2O2 with the terminal concentration of 0.0005% under microaerophili condition at 37℃. After inoculated in the mediums, the growth curve of each stain was determined and compared by Thermo Labsystems at an interval of 2 hours under 600nm. Results ①Growth cycle of the mutant strains changed in TPY medium.The exponential phase was ahead of time and the mutant strains grew faster than standard strains (P＜0.05).The peak value in exponential phase and A value in stationary phase of standard strains were higher than those of mutant strains(P＜0.05). ②Both strains grew slower in TPY medium containing H2O2. Conclusion Inactivation of clpP gene can reduce the capacity of Streptococcu mutans to grow and to resist oxidative stress.

Objective To observe the clinical efficacy of preparation of primary molars root canals with Protaper hand ni-ti file. Methods Select dental outpatients aged 4-8 years old who visited our department between 2010.1-2012.2, 160 primary molars which needed root canal treatment were randomly divided into two groups. 80 of them were prepared with Protaper hand ni-ti file crown-down the root, and the other 80 teeth were prepared with stainless steel K-file step by retreating preparation of the root canals. Metapex paste was injected into root canals, and immediately films were taken to evaluate the success rates of root canals. Assess pain rates in the return visit three days after the treatment. Results Pain rate of Protaper group was 3.75%, while pain rate of stainless steel K-file group was 15%, p <0.05, and there was significant difference. Success rate of the Protaper group was 95% , while success rate of stainless steel K-file group was 83.75% , p <0.05, and there was significant difference. Conclusion It is fast and efficient to use Protaper hand NiTi file in preparation of primary molars. Its tube pain response is light, and Its clinical efficacy is better than that of hand stainless steel K-file. So it's worthy of promotion.

Objective To study the law of basal thickness and translucency of two brands of translucent zirconia ceramics and IPS Empress II glass-ceremic so as to provide clinical reference for chosing and fabricating all-ceremic basal material aesthetically. Methods Four groups of square-shaped specimens (12 mm in length and 0.4 ,0.6, 0.8, or 1.0 mm in thickness) made of two kinds of translucent zirconia ceramics separately and another four groups of square-shaped Empress II glass-ceramic specimens (12 mm in length and 0.6, 0.8, 1.0, or 1.2 mm in thickness ) were fabricated, five disks per group. The relative translucency of each specimen was measured with a spectrophotometer after polishing. Results There were no significant differences in the relative translucency among three all-ceramic core materials in the same thickness (P>0.05). Increasing the thickness resulted in decrease of relative translucency. When the thickness of zirconia ceramic core materials was 0.4mm, the relative translucency was the best, which showed significant difference with other groups in the same material (P<0.05). Conclusion The translucency of all-ceramic core materials decreases along with the increase of thickness. The translucency of zirconia ceramic core materials is best in the thickness of 0.4mm, and the translucency of zirconia ceramic core materials in the thickness within 0.6~1.0 mm is similar to that of Empress II ceramic glass-ceramic material.

Objective To investigate prevalence and distribution of tooth agenesis (congenitally absent teeth, supernumerary teeth, impacted teeth and fused teeth) in a sample of patients who had malocclusion in Jiangsu area to support clinical work. Methods 1012 orthodontic patients at the first visit in Jiangsu Provincal Stomatological Hospital (416 males, 596 females, aged between 4 to 50 years) from June to September of 2012 were collected. Based on the radiography data, clinical examination and medical history, analyze the prevalence of congenitally absent teeth, supernumerary teeth, impacted teeth and fused teeth and their distribution in dentition Results The prevalence of congenitally hypodontia was 8.99 % (excluding the third molars), the most frequent missing tooth position was lower incisor. The prevalence of supernumerary teeth was 2.57%, most of them were located in palatal of upper central incisors and were impacted. The prevalence of impacted teeth was 8.79%, occurred most frequently in the maxillary canine. The prevalence of fused tooth was 0.69%, all cases were in mandibular anterior teeth. Conclusion There’s a high prevalance of tooth agenesis in orthodontic patients in Jiangsu Province, and congenitally absent teeth were most common, whose prevalence was significantly higher than average result in previous epidemiological studies. Impacted teeth come the second. Supernumerary teeth and fused teeth follow.

Objective To compare the results of lectures based learning(LBL)-problem based learning (PBL)-LBL model and LBL-PBL-LBL model in periodontology teaching . Methods Sixty students majoring oral medicine admitted in our department in 2011 were randomly divided into LBL-PBL group and LBL-PBL-LBL group (30 students in each group). The test scores and feedback scores of these students were statistically analysed. Results There was no significant difference in test scores between LBL-PBL group and LBL-PBL-LBL group （P>0.05）. Feedback scores in LBL-PBL-LBL group was significantly higher than those in LBL-PBL group（P<0.05）.Conclusions Both LBL-PBL-LBL model and LBL-PBL model are effective in periodontology teaching. They can both equip students with strong learning ability and flexible knowledge. However, LBL-PBL-LBL model is more suitable and valid in periodontology teaching. It can better arise students' leaning initiative, hence it's helpful for students to master basic theoretical knowledge, and improve students' ability in solving clinical problems.

Multiple symmetrical lipomatosis is a kind of rare lipodystrophia disease which usually occurs in middle-aged men addicted to alcohol．It is characterized by a diffuse, symmetric distribution of the nonenveloped adipose tissue in the cervical, nuchal, shoulder, upper extremity and back region. Operation has been the most effective treatment so far. The author tried to make a detailed introduction about the epidemiology, aetiology, clinical manifestation, diagnosis, therapeutics and prognosis of the disease by reviewing a case of multiple symmetrical lipomatosis and studying foreign and domestic literature.