Fabrication and accuracy research on 3D printing dental model based on cone beam computed tomography digital modeling / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The aim of this study is to build a digital dental model with cone beam computed tomography (CBCT), to fabricate a virtual model via 3D printing, and to determine the accuracy of 3D printing dental model by comparing the result with a traditional dental cast.</p><p><b>METHODS</b>CBCT of orthodontic patients was obtained to build a digital dental model by using Mimics 10.01 and Geomagic studio software. The 3D virtual models were fabricated via fused deposition modeling technique (FDM). The 3D virtual models were compared with the traditional cast models by using a Vernier caliper. The measurements used for comparison included the width of each tooth, the length and width of the maxillary and mandibular arches, and the length of the posterior dental crest.</p><p><b>RESULTS</b>3D printing models had higher accuracy compared with the traditional cast models. The results of the paired t-test of all data showed that no statistically significant difference was observed between the two groups (P>0.05).</p><p><b>CONCLUSIONS</b>Dental digital models built with CBCT realize the digital storage of patients' dental condition. The virtual dental model fabricated via 3D printing avoids traditional impression and simplifies the clinical examination process. The 3D printing dental models produced via FDM show a high degree of accuracy. Thus, these models are appropriate for clinical practice.</p>

Study on the consistency of the position of the brackets on the digital occlusal model and the actual position af-ter indirect bonding / 口腔疾病防治

Objective@#To provide the experimental basis for the coherence of the indirect bond position by comparing the position of the bracket on the digital occlusal model and the position of the transfer to the initial plaster model.@*Methods@#Fifteen digitized models were selected for the brackets on the dental denture model, the brackets were transferred to the initial plaster model by indirect bond transfer trays, The line distance between each bracket position in digital dental model and initial plaster model was measured with OrthoRx software. @*Results @#The difference between the position of the orthodontic brackets and the position of the initial plaster model was less than 0.20 mm, and the difference was statistically significant (P < 0.05). @*Conclusion @#The position of the bracket on the digital occlusal model is consistent with that of the original plaster model, which provides a theoretical basis for digital indirect bonding.

New prediction equations for the estimation of maxillary mandibular canine and premolar widths from mandibular incisors and mandibular first permanent molar widths: A digital model study / 대한치과교정학회지

OBJECTIVE: The primary aim of the study was to generate new prediction equations for the estimation of maxillary and mandibular canine and premolar widths based on mandibular incisors and first permanent molar widths. METHODS: A total of 2,340 calculations (768 based on the sum of mandibular incisor and first permanent molar widths, and 1,572 based on the maxillary and mandibular canine and premolar widths) were performed, and a digital stereomicroscope was used to derive the the digital models and measurements. Mesiodistal widths of maxillary and mandibular teeth were measured via scanned digital models. RESULTS: There was a strong positive correlation between the estimation of maxillary (r = 0.85994, r2 = 0.7395) and mandibular (r = 0.8708, r2 = 0.7582) canine and premolar widths. The intraclass correlation coefficients were statistically significant, and the coefficients were in the strong correlation range, with an average of 0.9. Linear regression analysis was used to establish prediction equations. Prediction equations were developed to estimate maxillary arches based on Y = 15.746 + 0.602 × sum of mandibular incisors and mandibular first permanent molar widths (sum of mandibular incisors [SMI] + molars), Y = 18.224 + 0.540 × (SMI + molars), and Y = 16.186 + 0.586 × (SMI + molars) for both genders, and to estimate mandibular arches the parameters used were Y = 16.391 + 0.564 × (SMI + molars), Y = 14.444 + 0.609 × (SMI + molars), and Y = 19.915 + 0.481 × (SMI + molars). CONCLUSIONS: These formulas will be helpful for orthodontic diagnosis and clinical treatment planning during the mixed dentition stage.

Evaluation of digital dental models obtained from dental cone-beam computed tomography scan of alginate impressions / 대한치과교정학회지

OBJECTIVE: To investigate the dimensional accuracy of digital dental models obtained from the dental cone-beam computed tomography (CBCT) scan of alginate impressions according to the time elapse when the impressions are stored under ambient conditions. METHODS: Alginate impressions were obtained from 20 adults using 3 different alginate materials, 2 traditional alginate materials (Alginoplast and Cavex Impressional) and 1 extended-pour alginate material (Cavex ColorChange). The impressions were stored under ambient conditions, and scanned by CBCT immediately after the impressions were taken, and then at 1 hour intervals for 6 hours. After reconstructing three-dimensional digital dental models, the models were measured and the data were analyzed to determine dimensional changes according to the elapsed time. The changes within the measurement error were regarded as clinically acceptable in this study. RESULTS: All measurements showed a decreasing tendency with an increase in the elapsed time after the impressions. Although the extended-pour alginate exhibited a less decreasing tendency than the other 2 materials, there were no statistically significant differences between the materials. Changes above the measurement error occurred between the time points of 3 and 4 hours after the impressions. CONCLUSIONS: The results of this study indicate that digital dental models can be obtained simply from a CBCT scan of alginate impressions without sending them to a remote laboratory. However, when the impressions are not stored under special conditions, they should be scanned immediately, or at least within 2 to 3 hours after the impressions are taken.