1.Effect of internal structures on the accuracy of 3D printed full-arch dentition preparation models in different printing systems
Teng MA ; Tiwu PENG ; Yang LIN ; Mindi ZHANG ; Guanghui REN
The Journal of Advanced Prosthodontics 2023;15(3):145-154
PURPOSE:
. The objective of this study was to investigate how internal structures influence the overall and marginal accuracy of full arch preparations fabricated through additive manufacturing in different printing systems.
MATERIALS AND METHODS:
. A full-arch preparation digital model was set up with three internal designs, including solid, hollow, and grid. These were printed using three different resin printers with nine models in each group. After scanning, each data was imported into the 3D data processing software together with the master cast, aligned and trimmed, and then put into the 3D data analysis software again to compare the overall and marginal deviation whose results are expressed using root mean square values and color maps. To evaluate the trueness of the resin model, the test data and reference data were compared, and the precision was evaluated by comparing the test data sets. Color maps were observed for qualitative analysis. Data were statistically analyzed by one-way analysis of variance and Bonferroni method was used for post hoc comparison (α = .05).
RESULTS:
. The influence of different internal structures on the accuracy of 3D printed resin models varied significantly (P < .05). Solid and grid models showed better accuracy, while the hollow model exhibited poor accuracy. The color maps show that the resin models have a tendency to shrink inwards.
CONCLUSION
. The internal structure design influences the accuracy of the 3D printing model, and the effect varies in different printing systems. Irrespective of the kind of printing system, the printing accuracy of hollow model was observed to be worse than those of solid and grid models. [J Adv Prosthodont 2023;15:145-54]
2.Comparison of three-dimensional position of maxillary dentition model treated with two digital transfer methods
Tiwu PENG ; Teng MA ; Zhikang YANG ; Mindi ZHANG ; Guanghui REN
Chinese Journal of Stomatology 2024;59(1):80-84
Objective:To compare and evaluate the difference in maxillary dentition position using an anatomical facebow and jaw movement analyzer.Methods:From March to May 2023, 15 medical interns from Yantai Stomatological Hospital were recruited, including 9 males and 6 females, aged 20-25 years. Digital models and plaster models of maxillary dentition were obtained from the 15 medical interns. The anatomical facebow group (AFB) and jaw movement analyzer group (JMA) were used to transfer the position of the maxillary dentition to the virtual articulator. The virtual occlusal articulator module of exocad denture design software was used to measure the inclination angle of the occlusal plane of the two groups, the distance between the mesio-incisal angle of the left maxillary central incisor and the lateral center point of the lateral condylar sphere of the virtual occlusal articulator, the distance between the mesial buccal cusp of the maxillary first molar and the lateral center point of the lateral condyle sphere of the virtual articulator. The same marks (mesial incisor point of left maxillary central incisor and mesial buccal cusp point of both maxillary first molars) were measured in two groups of maxillary dentition, and the root-mean-square error between 3 points was calculated.Results:The occlusal plane inclination angle in AFB group (9.11°±3.85°) was significantly larger than that in JMA group (4.94°±2.69°) ( t=10.45, P<0.001). There were significant differences between AFB and JMA groups. The distances from the mesial cusp of the left first molar to the lateral center of the left condylar, from the mesial cusp of the left maxillary central incisor to the lateral center of the left condylar[(91.75±3.05), (129.09±4.60) mm]were significantly smaller than those in the JMA group[(95.68±5.45), (132.41±5.64) mm]( t=-4.48, P=0.001; t=-4.21, P=0.001). In both groups of models, the distance of the mesial cusp of the left maxillary central incisor was (8.81±2.56) mm, and the distance between mesial buccal cusp of maxillary left first molar was (7.56±2.49) mm, the distance between mesial buccal cusp of maxillary right first molar was (7.13±2.77) mm; the root mean square error was (7.93± 2.94) mm. Compared with 0, the difference was statistically significant ( t=10.45, P<0.001). Conclusions:There were differences between the two methods (anatomical facebow and the jaw movement analyzer) for transferring the maxillary dentition position to the three-dimensional space position of the virtual articulator.
3.Willis covered stent in the treatment of traumatic carotid cavernous fistulae:a report of 7 cases
Yanting GAI ; Shubin TAN ; Muhua GONG ; Fangqiang PENG ; Wei WANG ; Yanjiang LI ; Mindi LIU ; Xuejun ZHANG ; Ran ZENG ; Donglei SONG
International Journal of Cerebrovascular Diseases 2018;26(12):908-911
Objective To evaluate the efficacy and safety of Willis covered stent in the treatment of traumatic carotid cavernous fistulae (tCCF).Methods The imaging and clinical data of 7 patients with tCCF treated with Willis covered stent in Shanghai Punan Hospital from November 2015 to June 2018 were analyzed retrospectively.Results Seven Willis covered stent were used in 7 patients.Immediately after stent release,angiography showed that the fistulae completely disappeared in 6 cases.One patient had a small amount of endoleak,and there was still a small amount of endoleaks after balloon dilatation.It was not further treated.There were no operative complications.During 3-12 months follow-up,no new neurological deficits were found in all patients.Angiographic follow-up of 2 patients showed that the fistulae completely disappeared without recurrence.The internal carotid arteries were patent,no in-stent stenosis and stent displacement.Conclusions Wills covered stent can be used as a treatment for tCCF.Its efficacy is satisfactory and the safety is good.
4.PET imaging on neurofunctional changes after optogenetic stimulation in a rat model of panic disorder.
Xiao HE ; Chentao JIN ; Mindi MA ; Rui ZHOU ; Shuang WU ; Haoying HUANG ; Yuting LI ; Qiaozhen CHEN ; Mingrong ZHANG ; Hong ZHANG ; Mei TIAN
Frontiers of Medicine 2019;13(5):602-609
Panic disorder (PD) is an acute paroxysmal anxiety disorder with poorly understood pathophysiology. The dorsal periaqueductal gray (dPAG) is involved in the genesis of PD. However, the downstream neurofunctional changes of the dPAG during panic attacks have yet to be evaluated in vivo. In this study, optogenetic stimulation to the dPAG was performed to induce panic-like behaviors, and in vivo positron emission tomography (PET) imaging with F-flurodeoxyglucose (F-FDG) was conducted to evaluate neurofunctional changes before and after the optogenetic stimulation. Compared with the baseline, post-optogenetic stimulation PET imaging demonstrated that the glucose metabolism significantly increased (P < 0.001) in dPAG, the cuneiform nucleus, the cerebellar lobule, the cingulate cortex, the alveus of the hippocampus, the primary visual cortex, the septohypothalamic nucleus, and the retrosplenial granular cortex but significantly decreased (P < 0.001) in the basal ganglia, the frontal cortex, the forceps minor corpus callosum, the primary somatosensory cortex, the primary motor cortex, the secondary visual cortex, and the dorsal lateral geniculate nucleus. Taken together, these data indicated that in vivo PET imaging can successfully detect downstream neurofunctional changes involved in the panic attacks after optogenetic stimulation to the dPAG.