Objective To explore the effect of different arch forms of maxillary models on stress distribution of peri-implant of All-on-4 implants with 3-dimensional finite element, and to provide evidence for the improvement of implant achievement ratio in clinic. Methods 3-dimensional finite element analysis models of Tapered,Square and Ovoid arch form maxillary based on the MBTTM Arch Form Templates were constructed by using Solidworks software.The cortical bone thickness was defined as 2 mm at all points.The implants with 13 mm in length were inserted between the mental foramina.The 2 posterior implants were set at 4 inclination angle,from 0°to 45°.All implants were splinted with superstructure.A 100 N pressure was applied to 2 kinds of loading positions on the superstructure models. The maximum Von-Mises stress on cortical bone around the implants was measured by using Abaqus software.Results The maximum Von-Mises value in maxillary cortical bone with All-on-4 implants in 3 arch forms showed significant differences. In Square model the concentration of stress was advanced with the increasing of implant inclination angle;In Ovoid model, the maximum Von-Mises value was observed at 1 5°in posterior region,and was increased significantly by pasted 15°in anterior region;In Tapered model,the Maximum Von-Mises value was increased greatly at 45°. Conclusion Arch forms have appreciable impact on stress distribution of peri-implant.In Square arch form,the inclination of implant should be avoided;in Ovoid arch form, the inclination angle should be under 15°;in Tapered arch form,the inclination should be under 30°.

Ionimplantationtechniqueisamethodthatprocessingthematerialsurfacesinordertochangetheirsurfacechemical,physical and mechanical properties in vacuum environment.Titanium and titanium alloys modified by different types of ions can change their surface properties and characteristics,thereby improving the osseointegration and antibacterial properties of titanium implant.This review summarizes the researches of titanium implant surface modified by different ions implanting.

OBJECTIVE： To observe the changes of insoluble particles of shuanghuanglian in quantity after mixed with benzylpenicillin,cefradine and dexamethasone in normal saline.METHODS： Using ZWF-4D particle counter,the number of insoluble particles in sizes of ≥ 2.0μ m,≥ 5.0μ m,≥ 10.0μ m and ≥ 25.0μ m was counted and compared before and after mixed with above-mentioned three drugs.RESULTS： The insoluble particles of Shuanghuanglian were obviously increased after mixed with benzylpenicillin,the particles in sizes of ≥ 5.0μ m,≥ 10.0μ m and ≥ 25.0μ m increased twice,23 and 94 times respectively.The insoluble particles were also increased after mixed with cefradine or dexamethasone,however,the increase rate was lower in comparison with that mixed with benzylpenicillin.CONCLUSION： Shuanghuanglian,used in combination with above-mentioned drugs,should be put into separate infusion bottle to avoid the increase of insoluble particles and ADRs.

0.05). The laser group with the dose of 3 J?cm-2 showed more increase in cell survival at 24 and 48 h after being seeded as compared with control group(P

OBJECTIVETo compare the accuracy of mesiodistal tooth angulation measurements by using traditional panoramic radiographs and cone beam CT (CBCT) panoramic images.

METHODSPlaster models of 15 volunteers with individual normal occlusions were collected. The functional occlusal plane and tooth long axis on the plaster models were marked from the right first molar to the left first molar in the upper and lower dental arches. A radiographic stent, which contains radiopaque markers near the functional occlusal plane and approximating the root axis, was fabricated for each model. Traditional panoramic radiographs and CBCT scan images were obtained from each patient, with the radiographic stent seated on the dentition. A panoramic image reconstruction was made from the CBCT volumetric data by using related software. The CBCT panoramic image data were oriented parallel to the maxillary or mandibular functional occlusal plane containing all the radiopaque markers when measuring the maxillary or mandibular teeth, respectively. The mesiodistal tooth angulations of the plaster model, traditional panoramic radiographs, and CBCT panoramic images were measured and compared. Multivariate analysis of variance and Dunnett-t test were performed to compare the differences among the three methods.

RESULTSThe difference among the three methods was statistically significant (P = 0.00). Significant differences compared with the model measurement were found in two teeth (upper second premolar and lower second premolar) among twelve teeth (P = 0.00) in traditional panoramic measurement. CBCT panoramic measurement was not significantly different to model measurement.

CONCLUSIONTraditional panoramic radiographs do not provide a more reliable measure of mesiodistal tooth angulation, whereas CBCT panoramic image is an tool for evaluating mesiodistal tooth angulation.

Bicuspid ; Cone-Beam Computed Tomography ; Dental Arch ; Dental Occlusion ; Humans ; Image Processing, Computer-Assisted ; Maxilla ; Molar ; Radiography, Panoramic ; Tooth ; Tooth Root

Objective; To investigate the stress distribution in implant-bone interface with different pitches by three-dimension finite element analysis method in order to decide the best design of thread parameters for stress distribution. Methods: Built three-dimension finite element models of partial mandible and dental implant with superstructure. The stress distributions in bone and three kinds of implants whose pitches were 0.6, 0.8 and 1.0 mm respectively, under axial and oblique 45 degree to axle concentrated load. Data were analyzed by Cosmos/works software. Results;The maximal Von-Mises stress, tensile stress and compressive stress of implant with 0.8 mm pitch were lower than others, the stress distribution was even. The stresses in the same model under oblique load were much higher than those under axial load. The stress concentrated more on implant neck, upper part of cortical bone and the lowest thread on implant. Conclusion; The pitch of implant has effect on stress distribution in implant-bone interface and the transmission of occlusal force. The lower threads on implant should be cut to avoid the concentration of stress, and the non-axial force should be reduced as possible as we can or avoided when we design and make implant denture.

BACKGROUND:There is often space between implant and bone during immediate implantation.Whether biological membrane is needed to guide bone regeneration remains poorly understood.OBJECTIVE:To createdifferent sizes of space between femurand implantsindogs and to observe the effects of biological membrane on bone regeneration capacity of bone defects surrounding implants.DESIGN,TIME AND SETTING:A self-control animal experiment was performed at the Laboratory Animal Center,Norman Bethune College of Medicine,Jilin University and School of Stomatology,Jilin University between March and December 2005.MATERIALS:BLB hydroxyapatite-coated implant was provided by Beijing Leiden Biomaterial Co.,Ltd.,China;BME-10X collagen membrane was purchased from Fujian Better Biotechnology Co..Ltd.,China.METHODS:BLB implants were installed in the bilateral proximal femoral bone to create standard gradient bone defects with horizontal width 3 mm.vertical depth 5 mm,and horizontal lengths of 0,1,2,3,and 4 mm Bone defects on the left femur were sutured directly and those on the right femur were covered with biological membrane prior to suture.All animals were sacrificed at 3 months after surgery.Specimens containing implants were harvested to prepare tissue blocks for radiological observation.MAIN OUTCOME MEASURES:The quantity,color,and texture of newly formed bone surrounding implants were observed from the surface and profile levels.The implant-bone integration and new bone formation were also examined by soft X-ray photography.RESULTS:Grossobservation results revealed that when the horizontal length of bone defect was 3 mm or less,there was no significant differenee in bone density between the newly formed bone and the host bone no matter whether biological membrane existed or not;when the horizontal length of bone defect was 4 mm the bone density was better when biological membranes were used than not.Soft X-ray photography results revealed that when the horizontal length ofbone defect was 3 mm or less.no significant difference in bone density and bone trabecular morphology and orientating was found between newly formed bone and host bone no matter whether biological membrane was used or not;in the 4-mm-length bone defect areas.implants contacted with newly formed bone directly,but the calcified degree ofnewly formed bone was poor,bone trabecula was thin,and bone trabecular course was irregular,nevertheless,the calcified degree of newly formed bone was better under the condition of being with biological membrane than without biological membrane.CONCLUSION:Biological membrane exhibits strong capacity to promote the regeneration and repair of bone defect tissue with a horizontal length of 3 mm or less,and plays an important role in repatr of large sizes of bone detect

Objective To explore the short-term and long-term effects ofapplication of Percutaneous Transhepatic Cholangioscopic Lithotripsy on the treatment of hepatolithiasis. Methods Eighty-threecases of hepatolithiasis were treated with the PTCSL and the other 87cases were treated with the Laparoscopic exploration lithotomy.The general clinical parameters , curative effect in the near future and long-term curative effect were anlyzed. Results No significant differences were found between the two groups in the general clinical parameters (P>0.05). The operation time,intraoperative blood transfusion volume and intraoperatve blood soss in group A were significantly shorter than those in group B(P<0.05, respectively). The original calculi residual rate was 2.4%, the eventually calculi residual rate was 4.8%and the recurrent cholangitis was4.8%in the model of PTCSL (Group A). The original calculi residual rate was 18.4%, the eventually calculi residual rate was 23.0% and the recurrent cholangitis was 23.0%in the model of Laparoscopic exploration lithotomy (Group B), with significant difference between these two groups (P<0.05). The calculi recurrence rate of group A was 12.0%,the calculi recurrence rate of group B was 22.9%,withno significant difference between these two group (P>0.05). No patients died in each group. The results of complications showed thatthe incidence of residual calculi of group A was significantly lower than that of group B (P<0.01). Conclusions Compared with the model of Laparoscopic exploration lithotomy, the PTCSL was more safe, minimally invasive and effective. The short-term efficacy of the model of PTCSL was better than that of the model of Laparoscopic exploration lithotomy.

Objective To evaluate the perinatal outcome of three types of monochorionic diamniotic (MCDA) twins with selective intrauterine growth restriction (sIUGR).Methods From January 2005 to June 2012,clinical data of 42 pairs of MCDA twins (84 fetuses) with sIUGR and 71 pairs of normal MCDA twins (142 fetuses) in the same period were analyzed retrospectively in the First Affiliated Hospital of Sun Yat-Sen University.Fetuses with sIUGR were classified into three groups based on umbilical artery Doppler flow.There were 25 cases of type Ⅰ,11 cases of type Ⅱ and 6 cases of type Ⅲ.The perinatal outcome was compared between sIUGR and normal MCDA twins,and among the three types of sIUGR as well.Perinatal outcomes included gestational age at delivery,rate of intrauterine fetal death (IUFD),birth weight,intertwin discordance of birth weight,neonatal death and survival rate at 6 months.Results (1) The gestational age of sIUGR at delivery was significantly earlier than the control group [(34 ± 3),(36 ±2) weeks,respectively],and the rate of IUFD of both fetuses of sIUGR was significantly higher (4.8％,0,respectively).In the sIUGR group,the average birth weight of large or small twins[(2130 ±.350),(1520 ±400) g,respectively] was smaller than those in the control group [(2470 ± 500),(2340 ± 460) g,respectively].The difference was statistically significant (P ＜ 0.05,P ＜ 0.01,respectively).The intertwin discordance of birth weight in sIUGR group was significantly larger (27.6％) than the control group(4.0％,P＜0.01).(2) The gestational age at delivery in type Ⅱ and type Ⅲ [(34 ±5),(34 ±2) weeks,respectively] was significantly earlier than the control group (P ＜ 0.05).The rate of IUFD of both fetuses in type Ⅱ (18％) was significantly higher than in type Ⅰ (0) and the control group (0,P ＜ 0.05).In sIUGR group,the average birth weight of small twins in type Ⅰ,type Ⅱ and type Ⅲ was (1640 ±430),(1330 ±310) and (1500 ±380) g respectively,all of which were significantly smaller than that in the control group (P ＜ 0.05).The average birth weight of small twins in type Ⅱ was smaller than in type Ⅰ and the difference was statistically significant (P ＜ 0.05).In sIUGR group,the intertwin discordance of birth weight in type Ⅰ,type Ⅱ and type Ⅱ was 24.1％,34.6％,31.3％ respectively,all of which were significantly larger than that in the control group(4.0％,P ＜ 0.05).There were no statistically significant differences of the intertwin discordance of birth weight among the three types of sIUGR(P ＞0.05).Survival rate at 6 months in type Ⅱ (64％) was significantly lower than in type Ⅰ (92％) and the control group (91.5％,P＜0.01).Conclusions The perinatal outcome of MCDA twins with sIUGR is poor.The outcome is different among the three types of sIUGR,and type Ⅰ is the worst.Type Ⅱ is associated with a high risk of intrauterine fetal demise.It is important to monitor the intrauterine situation closely.

Objective To study the influence of different implant diameters on the implant-bone-interface stress distributions in zygomatic implant denture and illustrate the correlation between implant diameter and long-dated success rate of zygomatic implant denture.Methods Three-dimensional finite element model for maxilla and zygoma was established biomechanically in this study by spiral CT technique and finite element software technique,and zygomatic implant was simulated into the model in the first-maxillary-molar region.Zygomatic-implant-denture load cases concerning different implant diameters(3.5,4.0 and 5.0 mm) were designed and loaded vertically,obliquely.The implant-bone-interface stress distributions were analyzed by 3-D finite element method.Results The model could be observed from any angle,and had good geometric similarity compared with CT image.Stress peak values among these load cases with different diameters were compared,the load case with 3.5 mm diameter appeared the largest stress peak value,the load case with 4.0 mm diameter appeared the larger stress peak value and the load case with 5.0 mm diameter appeared the least stress peak value.As the implant diamater increased(3.5 mm→4.0 mm→5.0 mm),the compressive and tensive stress peak values of implant-bone interface in the maxillary alveolar ridge and the zygomatic area near maxillary sinus roof decreased gradually,the stress of implant-bone interface in the maxillary alveolar ridge was significantly larger than that of implant-bone interface in the zygoma area and compressive stress peak value was larger than tensive stress peak value.Conclusion The implant-bone-interface stress distributions tend towards uniformity as the implant diameter increases.Select wider-diameter implant as possible as the residual bone permitted clinically.