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Objective@#To develop a method for generating three-dimensional (3D) digital models of the periodontal ligament (PDL) using 3D cone-beam computed tomography (CBCT) reconstruction and to evaluate the accuracy and agreement of the 3D PDL models in the measurement of periodontal bone loss. @*Methods@#CBCT data collected from four patients with skeletal Class III malocclusion prior to periodontal surgery were reconstructed at three voxel sizes (0.2 mm, 0.25 mm, and 0.3 mm), and 3D tooth and alveolar bone models were generated to obtain digital PDL models for the maxillary and mandibular anterior teeth. Linear measurements of the alveolar bone crest obtained during periodontal surgery were compared with the digital measurements for assessment of the accuracy of the digital models. The agreement and reliability of the digital PDL models were analyzed using intra- and interexaminer correlation coefficients and Bland–Altman plots. @*Results@#Digital models of the maxillary and mandibular anterior teeth, PDL, and alveolar bone of the four patients were successfully established. Relative to the intraoperative measurements, linear measurements obtained from the 3D digital models were accurate, and there were no significant differences among different voxel sizes at different sites. High diagnostic coincidence rates were found for the maxillary anterior teeth. The digital models showed high intra- and interexaminer agreement. @*Conclusions@#Digital PDL models generated by 3D CBCT reconstruction can provide accurate and useful information regarding the alveolar crest morphology and facilitate reproducible measurements. This could assist clinicians in the evaluation of periodontal prognosis and establishment of an appropriate orthodontic treatment plan.
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Objective@#To establish a quantitative three-dimensional method based on intraoral scan to evaluate the changes of soft tissue, and to evaluate the changes of supracrestal gingival thickness (SGT) in skeletal class Ⅲ patients induced by periodontal regenerative and corticotomy surgery (PRCS).@*Methods@#Twenty-two systematically and periodontally healthy skeletal class Ⅲ patients (4 males and 18 females, aged between 19 and 35 years), who were in need of combined orthodontic-orthognathic treatment and referred to the Department of Periodontology from the Department of Orthodontics and the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from January, 2018 to March, 2019, were collected in the study. The teeth involved were 112 anterior teeth (46 maxillary anterior teeth and 66 mandibular anterior teeth). PRCS in anterior tooth area was conducted before orthodontic decompensation. Probing depth (PD), bleeding index (BI) and keratinized gingiva width (KGW) were recorded before surgery and 6 months post-surgery. The intraoral digital impressions of maxillary and mandibular anterior teeth were obtained by 3-shape intraoral scanner before surgery and 6 months after surgery. The Standard Tessellation Language (STL) files were processed using Geomagic qualify 12.2 software to establish the soft tissue morphological measurement model, and to quantitatively analyze the changes of gingival thickness situated 1 to 2 mm apical to the free gingival margin on the median sagittal measurement plane.@*Results@#Probing depth and bleeding index had no significant difference before and 6 months after operation (P>0.05). KGW in 6-month post-operation group [(5.18±2.32) mm] was significantly higher than that in pre-operation group [(4.22±1.43) mm] (P<0.05). Supracrestal gingival thickness situated 1 to 2 mm apical to the free gingival margin also significantly increased 6 months after surgery (P<0.05). The changes of gingival thickness situated 1 to 2 mm apical to the free gingival margin in the upper anterior area were (0.68±0.56) and (1.00±0.69) mm, respectively. The changes in the lower anterior area were (0.38±0.42) and (0.58±0.45) mm, respectively. The gingival changes of the upper anterior teeth were also significantly higher than those of the lower anterior teeth (P<0.01).@*Conclusions@#The described quantitative measurement based on intraoral scan could be an effective method for quantitative evaluation of the changes of soft tissue. PRCS could safely increase the supracrestal gingival thickness as well as KGW in skeletal class Ⅲ patients who were in need of combined orthodontic-orthognathic treatment.
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Objective@#To establish a quantitative three-dimensional method based on intraoral scan and apply it to evaluation of the facial soft tissue contour alterations following single immediate implant and immediate provisionalization (IIPP) in central incisor via intraoral scanning.@*Methods@#This study was a prospective clinical study. The trial was conducted at Department of Implantology, Peking University School and Hospital of Stomatology, from January 2016 to September 2017. Twenty-nine eligible consecutive patients (15 women, 14 men) with a mean age of (34.3±12.0) were included and received immediate replacement of the failure maxillary single central incisor. A screw-retained immediate restoration was delivered for each patient. At 6-month follow-up, impression was taken and a screw-retained permanent restoration was performed for each patient. The anterior maxillary region was scanned by an intraoral scanning system at pre-surgery and 1-year follow-up. The Standard Tessellation Language (STL) files were output to a dedicated software and superimposed. Mid-facial recession and gingival zenith symmetry at 1-year follow-up were measured in the digital models. Three-dimensional configurations of the contour change volume were calculated and reconstructed for visual analysis. Furthermore, the following parameters were used to analyze the reconstructed volume: mean contour change in thickness (△d), mesio-distal width (DW), coronal-apical height (DH), contour change at 0, 1, 2, 3, 4, 5 mm apical to the free gingival margin on the implant site.@*Results@#Twenty-seven out of twenty-nine enrolled patients were finally available for analysis. At 1-year follow-up, the mid-facial mucosa level at implant site was (0.23±0.39) mm apical to the gingival zenith of the contralateral tooth. In general, a contour collapse was found in every patient. △d, DW and DH of the collapsed volume were (0.62±0.22), (11.03±1.74) and (6.82±1.52) mm, respectively. Contour change at 0, 1, 2, 3, 4, 5 mm apical to the free gingival margin on the implant site were (0.54±0.48), (0.87±0.62), (1.03±0.46), (0.96±0.52), (0.90±0.52), (0.89±0.57) mm.@*Conclusions@#The described quantitative measurement based on intraoral scan can be an effective method for assessment of soft tissue contour changes. At 1 year following single IIPP treatment in maxillary incisor, free gingival margin is stable, with only mild recession. The mean level of the facial soft tissue contour collapse is 0.62 mm.
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In recent years with the rapid development of digital technology for stomatology, the application field, application model, technical features and technical connotation of the chair-side digital technology has got development and change. The open modular system has gradually replaced the traditional closed system, and the application field of digital technology is no longer limited to chair-side dental restoration, it also has been extend to various kinds of chair-side digital treatment-assisted technology. In this paper, from the engineering point of view, the up to date general connotation of chair-side digital technology was explained, the characteristics and the development of each unit in chair-side digital technology were analyzed, and the application pattern and the localization status were also discussed in this paper. The aim of this paper was to introduce the trend of chair-side digital technological to readers and to better guide clinical application.
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Facial symmetry is a crucial component of human facial esthetics. Along with the increasing pursuit of aesthetic, in recent years, more and more researchers have focused on facial asymmetry assessment, of which determining the facial median sagittal plane is the first and most important step, and it will directly affect the accuracy of asymmetry evaluation and clinical treatment outcome. Limited by technical means, the earlier studies of facial soft tissue asymmetry assessment were mainly based on midline from two-dimensional (2D) images. Along with the development of three-dimensional (3D) measurement and data analysis techniques, new methods such as 3D landmark-based method and mirror-original alignment method have become main trend nowadays. This article systematically reviews the methods of determination of median sagittal plane of facial soft tissue, elaborates the developments and the latest research progress in this field, and discusses the advantages and limitations of each method in order to provide reference for clinical application.
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Objective This paper aimed at the management needs of the digital technique research-type laboratory of stomatology to explore a "three-stage training management" mode under the concept of "Standard Operating Procedures" (SOP) to improve the traditional training model for laboratory.Methods Experimental technology training management is an important step to insure the safely running of college research-type laboratory.Digital oral medical experimental technique is a kind of new technique developed in recent years,it is one of the important technical means of oral medical research today.In this paper,we based on the scientific research service demand of digital technique research-type laboratory in oral medical colleges explored and established a kind of three-stage training management mode under the concept of "Standard Operating Procedures".This training management mode included network self-study training,laboratory practical training and regular self-study training.Results The SOP training management model has achieved a good preliminary application effect in Peking University School and Hospital of Stomatology.Conclusions The training management model established in this study could improve the traditional training model and provide a theoretical support and experience for the domestic oral medical colleges.
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Objective:To explore a three-dimensional (3D) data fusion and integration method of optical scanning tooth crowns and cone beam CT (CBCT) reconstructing tooth roots for their natural transition in the 3D profile.Methods: One mild dental crowding case was chosen from orthodontics clinics with full denture.The CBCT data were acquired to reconstruct the dental model with tooth roots by Mimics 17.0 medical imaging software, and the optical impression was taken to obtain the dentition mo-del with high precision physiological contour of crowns by Smart Optics dental scanner.The two models were doing 3D registration based on their common part of the crowns'' shape in Geomagic Studio 2012 reverse engineering software.The model coordinate system was established by defining the occlusal plane.crown-gingiva boundary was extracted from optical scanning model manually, then crown-root boundary was generated by offsetting and projecting crown-gingiva boundary to the root model.After trimming the crown and root models, the 3D fusion model with physiological contour crown and nature root was formed by curvature continuity filling algorithm finally.In the study, 10 patients with dentition mild crowded from the oral clinics were followed up with this method to obtain 3D crown and root fusion models, and 10 high qualification doctors were invited to do subjective evaluation of these fusion models.Results: This study based on commercial software platform, preliminarily realized the 3D data fusion and integration method of optical scanning tooth crowns and CBCT tooth roots with a curvature continuous shape transition.The 10 patients'' 3D crown and root fusion models were constructed successfully by the method, and the average score of the doctors'' subjective evaluation for these 10 models was 8.6 points (0-10 points).which meant that all the fusion models could basically meet the need of the oral clinics, and also showed the method in our study was feasible and efficient in orthodontics study and clinics.Conclusion: The method of this study for 3D crown and root data fusion could obtain an integrate tooth or dental model more close to the nature shape.CBCT model calibration may probably improve the precision of the fusion model.The adaptation of this method for severe dentition crowding and micromaxillary deformity needs further research.
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Objective@#To quantitatively evaluate the adaptation of polylactic acid (PLA) pattern of mandibular complete denture fabricated by fused deposition modeling (FDM) technology.@*Methods@#A mandibular complete denture digital model was designed through a complete denture design software based on a pair of standard maxillomandibular edentulous plaster model and their occlusion bases. Ten PLA mandibular complete dentures were printed with a FDM machine. The dentures were scanned with and without the plaster model using a three-dimensional (3D) scanner. In Geomagic software, the scanning data of printed dentures were registered to its computer aided design (CAD) data, and the printing error was analyzed using the multipoint registration command. For quantitatively evaluating the adaptation of the denture, the data of plaster model and PLA denture were registered to the whole data of denture located in the plaster model using the best-fit alignment command, the 3D deviation of the plaster model and tissue surface of the denture represent the space between them. The overall area was separated into three parts: primary stress-bearing area, secondary stress-bearing area and border seal area, and the average deviations of these three parts were measured. The values were analyzed using analysis of variance.@*Results@#Compared with the CAD data, the printing error was (0.013±0.004) mm. The overall 3D deviation between PLA denture and plaster model was (0.164±0.033) mm, in which the primary stress-bearing area was (0.165± 0.045) mm, the secondary stress-bearing area was (0.153 ± 0.027) mm, the border seal area was (0.186 ± 0.043) mm. These showed a good fit in the majority parts of the FDM denture to the plaster model. No statistically significant difference was observed between the three areas (F=1.857, P=0.175>0.05).@*Conclusions@#Combined with the 3D scanning, CAD and FDM technology, a FDM 3D printing process of complete denture for injection moulding can be established. As a result, high efficiency and low cost can be used to print out the complete denture, to lay the basis for further clinical applications.
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Objective:To compare the accuracyof interactive closet point (ICP)algorithm,Procrustes analysis (PA)algorithm,andalandmark-independent method to construct the mid-sagittal plane (MSP)of the cone beam computed tomography.To provide theoretical basis for establishing coordinate systemof CBCT images and symmetric analysis.Methods:Ten patients were selected and scanned by CBCT before orthodontic treatment.The scan data was imported into Mimics 10.0 to reconstructthree dimensional skulls.And the MSP of each skull was generated by ICP algorithm,PA algorithm and landmark-independ-ent method.MSP extracted by ICP algorithm or PA algorithm involvedthree steps.First,the 3D skull processing was performed by reverse engineering software geomagic studio 2012 to obtain the mirror skull. Then,the original and its mirror skull was registered separately by ICP algorithm in geomagic studio 2012 and PA algorithm in NX Imageware 1 1 .0.Finally,the registered data were united into new data to calcu-late the MSP of the originaldata in geomagic studio 2012.The mid-sagittal plane was determined by SEL-LA (S),nasion (N),basion (Ba)as traditional landmark-dependent methodconducted in software InVivoDental 5.0.The distance from 9 pairs of symmetric anatomical marked points to three sagittal plane were measured and calculated to compare the differences of the absolute value.The one-way ANOVA test was used to analyze the variable differences among the 3 MSPs.The pairwise comparison was performed with LSD method.Results:MSPs calculated by the three methods were available for clinic analysis,which could be concluded from the front view.However,there was significant differences among the distances from the 9 pairs of symmetric anatomical marked points to the MSPs (F=10.932,P=0.001).LSD test showed there was no significant difference between the ICP algorithm and landmark-independent method (P=0.1 1 ),while there was significant difference between the PA algorithm and landmark-independent methods (P =0.01 ).Conclusion:Mid-sagittal plane of 3D skulls could be generated base on ICP algorithm or PA algorithm.There was no significant difference between the ICP algorithm and landmark-independent method.For the subjects with no evident asymmetry,ICP algorithm is feasible in clinical analysis.
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Objective:To evaluate the actual measurement accuracy of 2 three-dimensional(3D)facial scanners for real person. Methods:3D digital face models of 1 0 volunteers with normal ficial form were obtained by 3dMD and FaceScan facial scanners respec-tively.The measurement values of 1 0 feature lengths and 5 feature angles were measured on each 3D model by the software respective-ly.The reference values of all characteristics were acquired by line laser scanner (Faro)with high accuracy.Statistical and surveying analysis were taken between the measurement values and reference values.Facial morphology measurement error and actual accuracy of facial scanners were obtained finally.Data were statistically analysed.Results:The length measurement accuracy of 3dMD and FaceS-can was(-0.37 ±0.68)mm and (-0.29 ±0.53)mm(P =0.223),the angle measurement accuracy was (-0.22 ±2.1 4)°and (0.1 2 ±2.69)°(P =0.428),respectively.Conclusion:The 3D data of ficial morphology obtained by the 2 scanners are not signifi-cantly different.
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Objective:To study crown-root morphology of maxillary anterior teeth in ClassⅡ,division 2 malocclusion using cone-beam CT (CBCT)combined with computer aided measurement technology to provide guidance for clinical treatment.Methods:The samples which consisted of 36 cases radiographed with CBCT techniques were selected and divided into two groups (1 8 each )based on the type of maloc-clusion presented:ClassⅡ,division 2 group (groupⅡ2)and ClassⅠgroup (groupⅠ).The measure-ments of crown-root morphology including crown-root angle and surface-shaft angle were got by Multiple Planer Reconstruction of CBCT data uploaded into InvivoDental software 5.0.The data were processed with SPSS 20.0 software package and t test was employed for comparison of angular measurements. Results:In group Ⅰ,crown-root angles of maxillary central incisor,maxillary lateral incisor and maxillary canines were 1 79.08°±3.31 °,1 76.55°±2.77°and 1 84.20°±2.51 °respectively, surface-shaft angles were 21 .00°±2.63°,1 9.63°±2.35°and 1 9.36°±2.30°respectively. While in group Ⅱ 2 ,crown-root angles of maxillary central incisor,maxillary lateral incisor and maxillary canines were 1 76.80°±2.62°,1 74.1 3°±3.28°and 1 81 .79°±2.88°respectively, surface-shaft angles were 23.20°±2.95°,22.29°±2.1 9°and 20.61 °±2.34°respectively. Compared with group Ⅰ,significant statistical differences were observed with the exception of sur-face-shaft angle of maxillary incisor.There was significant difference in crown-root angle between group Ⅱ2 and 1 80 °.Conclusion:The maxillary anterior teeth in ClassⅡ,division 2 malocclusion exhibited significant crown-root morphology which would influence the torque after orthodontic treat-ment.Special attention should be paid to the position of maxillary anterior teeth roots during ortho-dontic treatment for Class Ⅱ,division 2 malocclusion.The ideal position of tooth movement should be decided by the root rather than the location of the crowns.
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Objective:To explore a method of constructing universal 3-dimensional (3D)colorized digital dental model which can be displayed and edited in common 3 D software (such as Geomagic se-ries),in order to improve the visual effect of digital dental model in 3D software.Methods:The mor-phological data of teeth and gingivae were obtained by intra-oral scanning system (3Shape TRIOS),con-structing 3D digital dental models.The 3D digital dental models were exported as STL files.Meanwhile, referring to the accredited photography guide of American Academy of Cosmetic Dentistry (AACD),five selected digital photographs of patients’teeth and gingivae were taken by digital single lens reflex camera (DSLR) with the same exposure parameters (except occlusal views ) to capture the color data.In Geomagic Studio 201 3,after STL file of 3D digital dental model being imported,digital photographs were projected on 3D digital dental model with corresponding position and angle.The junctions of different photos were carefully trimmed to get continuous and natural color transitions.Then the 3 D colorized digital dental model was constructed,which was exported as OBJ file or WRP file which was a special file for software of Geomagic series.For the purpose of evaluating the visual effect of the 3 D colorized digital model,a rating scale on color simulation effect in views of patients’evaluation was used.Sixteen patients were recruited and their scores on colored and non-colored digital dental models were recorded.The data were analyzed using McNemar-Bowker test in SPSS 20.Results:Universal 3D colorized digital dental model with better color simulation was constructed based on intra-oral scanning and digital photography. For clinical application,the 3D colorized digital dental models,combined with 3D face images,were in-troduced into 3D smile design of aesthetic rehabilitation,which could improve the patients’cognition for the esthetic digital design and virtual prosthetic effect.Conclusion:Universal 3 D colorized digital dental model with better color simulation can be constructed assisted by 3 D dental scanning system and digital photography.In clinical practice,the communication between dentist and patients could be improved as-sisted by the better visual perception since the colorized 3 D digital dental models with better color simula-tion effect.
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Objective To investigate the projects funded by ministry of national science and technology (NSTP) in China allocated to oral medicine from 2003 to 2013.Methods The data regarding the NSTP allocated to oral medicine research from 2003 to 2013 were collected,including funding years,the expenses and numbers of programs,the secondary discipline of oral medicine and the program units,etc.Multidimensional analyses were provided subsequently.Results From 2003 to 2013,a total number of 59 projects and 210 million CNY supported by NSTP were allocated to oral medicineresearch.The development trend showed increased year by year.The oral medicine researches were allocated by almost all major types of NSTP and the funding directions were tending to diversified development.But,the projects units were relatively concentrated in clinical,teaching and research institutions,only few enterprises.Conclusions Over the past 10 years,the sustainable improvement of NSTP in oral medicine research has led to the development of oral medicine discipline.NSTP has becoming an important way for oral medicine research to obtain State-level funding.
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Objective:To compare two digital methods of quantitatively accessing the degree of facial asymmetry by three-dimensional data.Methods: The three-dimensional data of 20 subjects were got by the FaceScan, and then were input to the reverse engineering software Imageware 13.0 and Geomagic 12 .Their mirror data were acquired and superimposed with the original data by the methods of interactive closest points ( ICP) and Procrustes analysis ( PA) .The mid-sagittal planes of the two methods were ex-tracted respectively, the degree of facial asymmetry and the distance of 21 automatic landmarks to mid-sagittal plane were calculated and compared.Results:The paired t test was taken and t=1.346, P=0.193.Conclusion:We can safely come to the conclusions that for the subjects with no evident facial asymmetry, there are no significant difference between the PA and the ICP methods for extracting the mid-sagittal plane from three-dimensional data.
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Objective:To evaluate facial soft tissue 3-deminsion changes of skeletal Class Ⅲmalocclu-sion patients after orthognathic surgery using structure light scanning technique .Methods:Eight patients [3 males and 5 females, aged ( 27.08 ±4.42 ) years ] with Class Ⅲ dentoskeletal relationship who underwent a bimaxillary orthognathic surgical procedure involving advancement of the maxilla by Le FortⅠosteotomy and mandibular setback by bilateral sagittal split ramus osteotomy (BSSO) and genioplasty to correct deformity were included .3D facial images were obtained by structure light scanner for all the patients 2 weeks preoperatively and 6 months postoperatively .The facial soft tissue changes were evalua-ted in 3-dimension.The linear distances and angulation changes for facial soft tissue landmarks were ana-lyzed.The soft tissue volumetric changes were assessed too .Results: There were significant differences in the sagittal and vertical changes of soft tissue landmarks .The greatest amount of soft tissue change was close to lips.There were more volumetric changes in the chin than in the maxilla , and fewer in the forehead .Conclusion: After biomaxillary surgery , there were significant facial soft tissue differences mainly in the sagittal and vertical dimension for skeletal Class Ⅲ patients .The structure light 3 D scan-ning technique can be accurately used to estimate the soft tissue changes in patients who undergo orthog-nathic surgery .
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<p><b>OBJECTIVE</b>To investigate the importance of root information in diagnosis set-up by constructing three-dimensional (3D) digital models with individual anatomic roots.</p><p><b>METHODS</b>Pretreatment cone-beam CT (CBCT) and laser scanning data were collected from two patients (extraction and non-extraction each) with skeletal Class I malocclusion. Threshold segmentation of the CBCT was performed to generate a 3D digital model which has individually isolated tooth. This model and the scan model were superimposed to generate an integrated model (Mo) composed of high-resolution surface scan crowns sutured to the CBCT roots. Pretreatment dentition plaster model were made into set-up model. The diagnosis model set-up was performed successively by three orthodontists and one senior orthodontic technician. Set-up model scan of each patient after tooth alignment was obtained. The isolated composite teeth were individually superimposed onto the set-up model surface scan to creat set-up model (Ma, Mb, Mc, Md) containing root position. These isolated composite teeth were also superimposed onto the posttreatment surface scan depicting the posttreatment model (M). In order to observe whether diagnosis model set-up would cause exposure of the root, Ma-Md were compared with Mo, which showed the true positions of alveolus. In order to validate the accuracy of the expected root position setup, Ma-Md were compared with the true root position represented by M. Color displacement maps generated to measure the discrepancies of root positions.</p><p><b>RESULTS</b>Nonparallel and exposure of the root was found in all setup models. Color displacement maps through molar superimpositions showed maximum differences of 8.79 mm for the maxillary teeth and 9.96 mm for the mandibular teeth.</p><p><b>CONCLUSIONS</b>Diagnosis model set-up based only on crown can not absolutely ensure the good alignment of roots without root exposure. It is necessary to construct the integrated model including root for diagnosis during tooth arrangement process.</p>
Subject(s)
Humans , Cone-Beam Computed Tomography , Dental Casting Technique , Image Processing, Computer-Assisted , Lasers , Malocclusion, Angle Class I , Diagnosis , Molar , Pilot Projects , Tooth , Tooth Crown , Diagnostic Imaging , Tooth Root , Diagnostic ImagingABSTRACT
Objective To investigate a retrieval strategy for dentistry literature based on medical subject headings (MeSH). Methods We analysed the MeSH Tree Structures of PubMed in 2009 and combined it with the core glossary of dentistry to find out highly frequent dental words in MeSH. Then 6 words were singled out from the whole MeSh Tree to apply for a retrieval strategy for dentistry literatures. Results 102,500 pieces of dentistry literature were obtained from the year 2006 to 2008. Conclusions This research strategy can improve the efficiency of literature search in dentistry field for clinical or laboratory researches.
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Objective: To acquire the 3D point-cloud of the dental casts of intercuspal position and rebuild it in computer. Methods:Aspecial scanning method was used to acquire the point-cloud of dental cast by using the D.02-L-3D SCANNER and rebuild the model by computer. Results: The method could acquire a 3D model with high resolving power and clear-cut dental anatomic configuration for the dental casts of intercuspal position. Conclusion: This is a viable method of scanning with many advantages, such as precision, simplicity , high efficiency. It could satisfy the requirements of clinical practice, teaching and scientific research.