In this paper,the attachment of a China-made removable clear orthodontics appliances are introduced. The clinical attachment positions and considerations were illustrated with clinical pictures. A typical case was attached for demonstration.

Crossbite of upper and lower second molars is a common malocclusion. It is difficult to treat such cases. 4 kinds of treatments according to different situations are recommended. One is a mutual elastics on the upper and lower teeth. The second method is to move upper and lower teeth by archwire lingually and bucally. The third is to extract the second molars, while the third molars drift automatically. The fourth is using mini-implant as an anchorage to move the teeth to correct position. This article evaluated the advantages and disadvantages of the 4 kinds of methods. We also discussed how to choose the appliances as well as what we should pay attention to treat this malocclusion.

Objective:To establish a three-dimensional visualization model of craniofacial hard and soft tissues with data based on CT. It could be used in clinic as diagnosis and operation simulation. Methods:Original data of patients' craniofacial hard and soft tissues by CT scanning was transferred into the system. After 2-D and 3-D image preprocessing, advanced Marching Cubes Algorithm (Marching Tetrahedron Algorithm) was used for surface fitting;3-D volume rendering was accomplished by footprint method. Results: The whole craniofacial frame and its surface could be observed clearly in reconstructed 3-D Model. Furthermore, the 3-D Model could be seen from any sight angle and sectioned in any direction and place. Doctors could observe the characters of craniofacial deformity for more details. Conclusion: The problems of X-ray reflection of metal brackets, control of X-ray dosage and time spending in 3-dimensional visualization model reconstruction were solved. This model could be used in clinic for diagnosis and operation simulation.

Clear aligner, covering the whole dentition, is considered to offer more stable anchorage units, which means the whole dentition would act as a strong anchorage except the teeth designed to move. Although we don′t expect any movement of the anchorage teeth, it actually happens. It reminds us to pay attention to anchorage problems. In this article we have discussed the anchorage design in clear aligner therapy, compared clear aligner with traditional fixed appliance on anchorage control and provided some clinical strategies of anchorage design in vertical, sagittal and transverse tooth movement.

Objective:To explore the force distribution on the maxillary dentition when the first and second molars distalized simultaneously with different step sizes using clear aligners in vitro in order to provide a theoretical basis for the rational design of molar distalization. Methods:Clear aligners were designed to simultaneously distalize the maxillary first and second molars bilaterally, with rectangular attachments placed on the buccal surfaces of the first and second premolars, as well as the second molars. Based on different step sizes, the aligners were divided into three groups: Group A (0.15 mm per step), Group B (0.20 mm per step), and Group C (0.25 mm per step). Ten aligners were fabricated for each group using 0.76 mm thick polyethylene terephthalate glycol (PET-G) sheets. A three-dimensional force measurement system was used to measure the forces exerted on each tooth by the aligners, the first and second molars served as the target teeth and the remaining teeth as anchorage teeth. The three-dimensional force data were compared among the three groups.Results:In the mesiodistal direction, the forces on the central and lateral incisors were relatively small among all three groups, with no statistically significant differences ( P>0.05). However, significant differences were observed in the forces on the canines, first premolars, second premolars, first molars, and second molars ( P<0.05). The distal forces on the second molars in Groups B and C were (6.13±1.45) N and (6.83±1.58) N, respectively, significantly higher than that in Group A [(3.51±1.01) N] ( P<0.05). The distal force on the first molars in Group C [(6.62±0.89) N] was significantly higher than that in Groups A and B ( P<0.05). The mesial reactive forces on the first and second premolars in Groups B and C were significantly higher than those in Group A ( P<0.05). The mesial reactive force on the canines in Group C [(-2.98±1.33) N] was significantly higher than that in Group A [(-1.69±0.68) N] ( P<0.05), while there were no significant differences between Groups B and C in the forces on the canines, first premolars, and second premolars ( P>0.05). In the buccolingual direction, there were no statistically significant differences in the forces on the central and lateral incisors among three groups ( P>0.05), but significant differences were observed in the forces on the canines, second premolars, and second molars ( P<0.05). The buccolingual forces on the canines, second premolars, and second molars in Group B were (-0.56±0.54), (-2.07±0.95), (1.13±0.55) N, respectively, significantly higher than those in Group A ( P<0.05), but there were no significant differences compared to Group C ( P>0.05). Compared to the mesiodistal and buccolingual forces, the vertical forces on the target and anchorage teeth were relatively small in all three groups. Conclusions:When using 0.76 mm thick PET-G sheets to fabricate clear aligners for simultaneous molar distalization, a step size of 0.20 mm per step is recommended. To prevent buccal tipping of the molars during distalization, it is advisable to design lingual displacement for the molars and buccal displacement for the adjacent anchorage teeth to counteract the unfavorable forces, with attachments placed on the primary anchorage teeth.

BACKGROUNDThe pain caused by orthodontic treatment has been considered as tough problems in orthodontic practice. Danggui-shaoyao-san (DSS) is a traditional Chinese medicine (TCM) prescription which has long been used for pain treatment and possesses antioxidative, cognitive enhancing and antidepressant effects. We raise the hypothesis that DSS exerts analgesic effect for orthodontic pain via inhibiting the activations of neuron and microglia.

METHODSDSS was given twice a day from day 5 prior to experimental tooth movement (ETM). Directed face grooming and vacuous chewing movements (VCM) were evaluated. Immunofluorescent histochemistry and Western blot analysis were used to quantify the Iba-1 (microglia activation) and Fos (neuronal activation) expression levels in the trigeminal spinal nucleus caudalis (Vc).

RESULTSETM significantly increased directed face grooming and VCM which reached the peak at post-operative day (POD) 1 and gradually decreased to the baseline at POD 7. However, a drastic peak increase of Fos expression in Vc was observed at 4 hours and gradually decreased to baseline at POD 7; while the increased Iba-1 level reached the peak at POD 1 and gradually decreased to baseline at POD 7. Furthermore, pre-treatment with DSS significantly attenuated the ETM induced directed face grooming and VCM as well as the Fos and Iba-1 levels at POD 1.

CONCLUSIONTreatment with DSS had significant analgesic effects on ETM-induced pain, which was accompanied with inhibition of both neuronal and microglial activation.

Animals ; Drugs, Chinese Herbal ; therapeutic use ; Face ; physiology ; Male ; Mastication ; physiology ; Medicine, Chinese Traditional ; methods ; Microglia ; drug effects ; physiology ; Neurons ; drug effects ; physiology ; Pain ; drug therapy ; Pain Management ; methods ; Postoperative Period ; Rats ; Rats, Sprague-Dawley ; Tooth Movement Techniques ; adverse effects

OBJECTIVES: This study aimed to investigate the accuracy of model superimposition and automatic analysis for upper and lower dentition widths in iTero Progress Assessment during the clear aligner process. METHODS: Nineteen cases were included in this retrospective case control study. Pretreatment dental cast (T0) and post treatment dental cast after staged treatment (T1) were available for three-dimensional (3D) model superimposition. The movements of maxillary teeth in the horizontal plane (cross section) after staged treatment and the widths of upper and lower dentitions were measured by 3D model superimposition in real world and iTero Progress Assessment. The data collected from the two methods were compared. RESULTS: The movements [Median (upper and lower quartiles)] of maxillary teeth in the horizontal plane after staged treatment were 2.31 (1.59, 3.22) and 1.79 (1.21, 3.03) mm in iTero Progress Assessment and 3D model analysis, respectively. Significant difference was observed between the two groups (P<0.05). In the measurement of upper and lower dentition width, four indicators were measured, including intercanine width upper, intermolar width upper, intercanine width lower, and intermolar width lower. Before treatment, the measurement of iTero Progress Assessment were (35.78±2.49), (56.21±2.51), (27.43±1.38), (52.26±2.91) mm, respectively, and actual measurement were (35.77±2.53), (56.17±2.47), (27.40±1.41), (52.30±2.86) mm, respectively, without significant difference (P>0.05). After stage treatment, the measurement of iTero Progress Assessment were (37.37±2.86), (57.76±2.56), (28.89±2.00), (54.16±2.19) mm, respectively, and actual measurement were (37.29±2.94), (57.71±2.63), (28.88±2.05), (54.01±2.15) mm, respectively, and there was no significant difference (P>0.05). CONCLUSIONS The data from iTero Progress Assessment did not coincide with the model superimposition results with palate as reference. The accuracy of model superimposition in iTero Progress Assessment needs further investigation, whereas the arch width analysis is accurate. Therefore, iTero Progress Assessment results should be interpreted with caution by orthodontists in clinical applications.
Case-Control Studies ; Cuspid ; Dental Arch ; Orthodontic Appliances, Removable ; Retrospective Studies ; Humans