Objective To observe the porcelain treated with Nd∶YAG laser irradiation and hydrofluoric acid (HF), and to explore the influence of integrated treatment of Nd ∶ YAG laser irradiation and HF etching in the bond strength of brackets to porcelain.Methods 48 metal ceramic prostheses were randomly divided into untreated control group,HF group,grooved treatment group,0.75W laser group,1.05W laser group,1.45W laser group. All samples were bonded to the brackets.After temperature cycling test,the shear bond strength (SBS)and tensile bond strength (TBS)were measured.Results There were significant differences in SBS and TBS between various surface treatment groups and untreated control group (P < 0.01).The SBS and TBS of brackets bonded in HF group was significantly higher than those in 1.05W laser and 1.45W laser groups (P <0.05).The SBS and TBS in 1.05W laser and 1.45W laser groups were higher than those in HF group (P <0.05).The SBS and TBS in 1.05W laser group were higher than those in other groups (P < 0.05).SBS showed positive correlation with TBS (r =0.426,P =0.000).Conclusion The use of Nd∶YAG laser irradiation with the energy parameter of 1.05W and HF could increase the bonding with formation of composite resin,and the more SBS,the more TBS.

Objective:To investigate the effect of ciwujia Injection and Jiangxianmei combination for acute cerebral infarction. Methods:86 patients with cerebral infarction were divided into 2 groups. 43 cases in the treatment group were dripped intravenously with 60ml ciwujia Injection and 250ml physiological saline. 43 cases in the control group were treated only with Jiangxianmei. Both of groups were also treated with other therapeutic method. The hemorheology and blood fat of patients in two groups before and after treatment were determined. Results:The cure rate of the treatment groups in two weeks was 41.86%, which is superior to the control group (20.93%) ( x 2=4.37,P0.05). The treatment group was superior to the control group in improving hemorheological index and blood fat metabolism ( P

OBJECTIVEThe purpose of this study was to investigate the effects of low power laser on basic fibroblast growth factors (bFGF) expression in periodontal tissue during tooth movement.

METHODS18 white rabbits were randomly divided into 6 groups with 3 rabbits in each group, including groups of 1, 3, 5, 7, 14 and 21 days. Under an anesthesia condition by 2% pentobarbital sodium, the stainless coil springs were fixed between the first maxillary molar and the incisor producing the force of 80 g. The right side of maxilla was considered as the experimental group under the irradiation of low power laser with the left side as the control groups. The expression of bFGF was investigated half-quantitatively through immunohistochemical analysis.

RESULTSThe expression of bFGF in periodontal tissue with irradiation of low power laser was higher than the control side. There were significant differences among the 5, 7, and 14 day groups. In the tension area of the experimental side, the expression of bFGF in the osteoblastic surface of alveolar bone was characteristically greater than that of the control side.

CONCLUSIONThe laser of low power promotes the expression of bFGF in the periodontal tissue and alveolar bone remodeling.

Alveolar Process ; metabolism ; Animals ; Female ; Fibroblast Growth Factor 2 ; biosynthesis ; radiation effects ; Low-Level Light Therapy ; Male ; Orthodontics, Corrective ; Periodontal Ligament ; metabolism ; radiation effects ; Periodontium ; metabolism ; radiation effects ; Rabbits ; Random Allocation ; Tooth Movement Techniques

OBJECTIVEThis study aims to analyze the biomechanical effects of four sutures that are related to maxillary growth during a maxillary protraction treatment cycle based on labiolingual appliance.

METHODSA three-dimensional simulation of labiolingual appliance was performed based on a three-dimensional finite-element maxillofacial model combined with solid-modeled sutures.

RESULTSThe displacement and stress distributions were calculated. The labiolingual appliance was suitable for patients with underbites or deep overbites. Sutura frontomaxillaris and sutura zygomaticomaxillaris were vital to the forward displacement and counterclockwise rotation of the maxillary. The changes in sutura zygomaticotemporalis and sutura palatine were not significant.

CONCLUSIONThe influences of the labiolingual appliance on the sutures during the treatment cycle of maxillary protraction can be effectively simulated by the three-dimensional finite-element maxillofacial model.

Biomechanical Phenomena ; Cranial Sutures ; Finite Element Analysis ; Humans ; Imaging, Three-Dimensional ; Malocclusion, Angle Class III ; Maxilla ; growth & development ; Orthodontic Appliances ; Skull

OBJECTIVEIn order to find out the cause of molar intrusion and how to avoid molar intrusion, we analyze the movement tendency of tooth by changing the angles of upper accentuated-curve and the height of free traction hook.

METHODSSpiral CT scanning and Mimics 10.0 software were employed in this study to construct the three dimensional finite element model of maxillary teeth, periodontal ligaments and alveolar bone as well as the inch stainless steel upper accentuated-curve archwires with different angles (5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees) and the free traction hook with different height (2.1, 4.0, 5.5 mm). By exerting 1.5 N backward force to analysis the displacement trend of maxillary tooth.

RESULTSUpper accentuated-curve archwires made the incisors labially tip, intruse, distally upright and mesilabially torsion; made the canines labially tip, prolong, mesial-tipped and mesi-labially torsion; made the second premolars and the first molars buccal tip, intruse, distal upright and mesi-labially torsion. With the angle of upper accentuated-curve archwires increased, all tooth movement tendency increased; while with the height of free traction hook increased, all tooth movement tendency decreased.

CONCLUSIONWhen the angle of upper accentuated-curve archwires increased, the extent of molar intrusion increased, but when the height of free traction hook increased, the degree of molar intrusion decreased. The degree of molar intrusion was minimum using 5 degrees upper accentuated-curve archwires cooperated with 5.5 mm free traction hook.

Bicuspid ; Bone Screws ; Finite Element Analysis ; Humans ; Incisor ; Maxilla ; Molar ; Periodontal Ligament ; Tooth ; Tooth Movement Techniques

OBJECTIVETo evaluate the influence of different surface treatments on porcelain surface topography.

METHODSMetal ceramic prostheses in 6 groups were treated according to the different surface treatment methods, and the surface topography was observed through scanning electron microscope (SEM). Group A was the control one (untreated), group B was etched by 9.6% hydrofluoric acid(HF), group C was deglazed by grinding and then etched by 9.6% HF, group D was treated with Nd: YAG laser irradiation(0.75 W) and HF etching, group E was treated with Nd: YAG laser irradiation (1.05 W) and HF etching, and group F was treated with laser irradiation (1.45 W) and HF etching.

RESULTSSurface topography was different in different groups. A lot of inerratic cracks with the shapes of rhombuses and grid, and crater with a shape of circle were observed on the ceramic surface after treatment with energy parameters of 1.05 W Nd: YAG laser irradiation and 9.6% HF etching (group E). Surface topography showed a lot of concaves on the inner wall of the cracks, and the concaves with diameter of 1-5 microm could be observed on the inner wall of the holes, which had a diameter of 20 microm under SEM.

CONCLUSIONThe use of Nd: YAG laser irradiation with the energy parameters of 1.05 W and the HF with a concentration of 9.6% can evenly coarsen the porcelain surface, that is an effective surface treatment method.

Ceramics ; Dental Bonding ; Dental Porcelain ; Hydrofluoric Acid ; Lasers, Solid-State ; Shear Strength ; Surface Properties

Objective To evaluate the clinical efficacy of invisible orthodontic appliances without brackets for the distal movement of maxillary molars to improve the ability of orthodontists to predict treatment outcomes.Methods Web of Science,Cochrane Library,Embase,PubMed,Wanfang Database,CNKI Database,and VIP Database were searched for studies investigating the efficacy of invisible orthodontic appliances for distal movement of maxillary molars in adult patients and published from database inception to August 1,2023.A total of three researchers screened the studies and evaluated their quality and conducted a meta-analysis of those that met quality standards.Results This study included 13 pre-and postcontrol trials with a total sample size of 281 patients.The meta-analysis revealed no sig-nificant differences in the sagittal or vertical parameters of the jawbone after treatment when compared with those before treatment(P＞0.05).The displacement of the first molar was MD=-2.34,95％CI(-2.83,-1.85);the displacement was MD=-0.95,95％CI(-1.34,-0.56);and the inclination was MD=-2.51,95％CI(-3.56,-1.46).There was a statistically significant difference in the change in sagittal,vertical,and axial tilt of the first molar before and after treatment.After treatment,the average adduction distance of the incisors was MD=-0.82,95％CI(-1.54,-0.09),and the decrease in lip inclination was MD=-1.61,95％CI(-2.86,-0.36);these values were significantly different from those before treat-ment(P＜0.05).Conclusion Invisible orthodontic appliances can effectively move the upper molars in a distal direc-tion and control the vertical position of the molars.When the molars move further away,there is some degree of com-pression and distal tilt movement,which is beneficial for patients with high angles.The sagittal movement of incisors is beneficial for improving the patient's profile.

Objective To explore the effect of different miniscrew placement heights on the distribution of biologi-cal forces produced by clear aligner combined with intramaxillary traction for mandibular molar distalization,to identify the miniscrew location that is conducive to the protection of lower anterior tooth anchorage and to provide a reference that can be used when designing clinical treatments.Methods Mimics,GeomagicStudio 2017,SolidWorks 2016,and Ansys workbench were used to establish finite element analysis models and perform mechanical analysis under the fol-lowing six working conditions:working condition 1 was the control group without miniscrews;working conditions 2 to 5 had miniscrew in the buccal bone cortex between the first and second molars of the lower jaw 10 mm,7 mm,4 mm,and 1 mm from the top of the alveolar crest,respectively;working condition 6 had the miniscrew in the center of the buccal tongue at the anterior edge of the ascending branch of the lower jaw 5 mm above the occlusal plane.Results On the sagittal axis,miniscrew anchorage caused distal displacement of all teeth.Compared to the control group,in the miniscrew group,the displacement of the anterior molars exceeded that of the second molars.On the vertical axis,the result in the control group was similar to backward bending;the results in the miniscrew groups resembled the effect of a lever,lowering the lateral incisors and canines and raising the central incisors and first premolars.On the coronal ax-is,the second premolars and the first molars showed lingual displacement in the control group,and only the premolars and first molars showed lingual displacementin the miniscrew groups.The canines were the teeth that were most strong-ly affected by the change in miniscrew placement height.Conclusion The higher the miniscrew position is,the stron-ger the protective effect on the anterior anchorage.According to the miniscrew placement height,the mandibular arch should be properly narrowed,the central incisors and first premolars should be lowered,and the lateral incisors and ca-nines should be raised when designing clinical treatments.

Objective To explore the effect of different miniscrew placement heights on the distribution of biologi-cal forces produced by clear aligner combined with intramaxillary traction for mandibular molar distalization,to identify the miniscrew location that is conducive to the protection of lower anterior tooth anchorage and to provide a reference that can be used when designing clinical treatments.Methods Mimics,GeomagicStudio 2017,SolidWorks 2016,and Ansys workbench were used to establish finite element analysis models and perform mechanical analysis under the fol-lowing six working conditions:working condition 1 was the control group without miniscrews;working conditions 2 to 5 had miniscrew in the buccal bone cortex between the first and second molars of the lower jaw 10 mm,7 mm,4 mm,and 1 mm from the top of the alveolar crest,respectively;working condition 6 had the miniscrew in the center of the buccal tongue at the anterior edge of the ascending branch of the lower jaw 5 mm above the occlusal plane.Results On the sagittal axis,miniscrew anchorage caused distal displacement of all teeth.Compared to the control group,in the miniscrew group,the displacement of the anterior molars exceeded that of the second molars.On the vertical axis,the result in the control group was similar to backward bending;the results in the miniscrew groups resembled the effect of a lever,lowering the lateral incisors and canines and raising the central incisors and first premolars.On the coronal ax-is,the second premolars and the first molars showed lingual displacement in the control group,and only the premolars and first molars showed lingual displacementin the miniscrew groups.The canines were the teeth that were most strong-ly affected by the change in miniscrew placement height.Conclusion The higher the miniscrew position is,the stron-ger the protective effect on the anterior anchorage.According to the miniscrew placement height,the mandibular arch should be properly narrowed,the central incisors and first premolars should be lowered,and the lateral incisors and ca-nines should be raised when designing clinical treatments.

Objective To explore the effect of different miniscrew placement heights on the distribution of biologi-cal forces produced by clear aligner combined with intramaxillary traction for mandibular molar distalization,to identify the miniscrew location that is conducive to the protection of lower anterior tooth anchorage and to provide a reference that can be used when designing clinical treatments.Methods Mimics,GeomagicStudio 2017,SolidWorks 2016,and Ansys workbench were used to establish finite element analysis models and perform mechanical analysis under the fol-lowing six working conditions:working condition 1 was the control group without miniscrews;working conditions 2 to 5 had miniscrew in the buccal bone cortex between the first and second molars of the lower jaw 10 mm,7 mm,4 mm,and 1 mm from the top of the alveolar crest,respectively;working condition 6 had the miniscrew in the center of the buccal tongue at the anterior edge of the ascending branch of the lower jaw 5 mm above the occlusal plane.Results On the sagittal axis,miniscrew anchorage caused distal displacement of all teeth.Compared to the control group,in the miniscrew group,the displacement of the anterior molars exceeded that of the second molars.On the vertical axis,the result in the control group was similar to backward bending;the results in the miniscrew groups resembled the effect of a lever,lowering the lateral incisors and canines and raising the central incisors and first premolars.On the coronal ax-is,the second premolars and the first molars showed lingual displacement in the control group,and only the premolars and first molars showed lingual displacementin the miniscrew groups.The canines were the teeth that were most strong-ly affected by the change in miniscrew placement height.Conclusion The higher the miniscrew position is,the stron-ger the protective effect on the anterior anchorage.According to the miniscrew placement height,the mandibular arch should be properly narrowed,the central incisors and first premolars should be lowered,and the lateral incisors and ca-nines should be raised when designing clinical treatments.