• Korean Journal of Computational Design and Engineering
• /
• v.16 no.3
• /
• pp.216-226
• /
• 2011

Surgeon dentists usually rely on their experiential judgments from patients' oral plaster casts and medical images to determine the positional and directional information of implant fixtures and to perform drilling tasks during dental implant surgical operations. This approach, however, may cause some errors and deteriorate the quality of dental implants. Computer-aided methods have been introduced as supportive tools to alleviate the shortcomings of the conventional approach. In this paper, we present an approach of 3D dental implant simulation which can provide the realistic and immersive experience of dental implant information. The dental implant information is primarily composed of several kinds of 3D mesh models obtained as follows. Firstly, we construct 3D mesh models of jawbones, teeth and nerve curves from the patient's dental images using software $Mimics^{TM}$. Secondly, we construct 3D mesh models of gingival regions from the patient's oral impression using a reverse engineering technique. Thirdly, we select suitable types of implant fixtures from fixture database and determine the positions and directions of the fixtures by using the 3D mesh models and the dental images with software $Simplant^{TM}$. Fourthly, from the geometric and/or directional information of the jawbones, the gingival regions, the teeth and the fixtures, we construct the 3D models of surgical guide stents which are crucial to perform the drilling operations with ease and accuracy. In the application phase, the dental implant information is combined with the tangible interface device to accomplish 3D dental implant simulation. The user can see and touch the 3D models related with dental implant surgery. Furthermore, the user can experience drilling paths to make holes where fixtures are implanted. A preliminary user study shows that the presented approach can be used to provide dental students with good educational contents. With future work, we expect that it can be utilized for clinical studies of dental implant surgery.

• Journal of Technologic Dentistry
• /
• v.34 no.4
• /
• pp.413-421
• /
• 2012

Purpose: The purpose of this study is to investigate the improvement measure of dental technician practical examination. Methods: A survey was performed on 111 dental technicians who were self-written questionnaire. The results were analyzed by SPSS 12.0. The collected data was analyzed by frequency and chi-square test. Results: Questions most necessary work tools with the articulator was the highest with 55.9%, Electric wax carver(16.2%), heating clear(14.4%), CAD/CAM program(9.0%) was in the order. The need for additional practical test in response to actions included maxillary and mandibular comments occlusal work that you have to wax up the highest rate of 63.8%. Items most in need of improvement was strengthen of clinically oriented(48.0%), separation of written and practical(14.6%), control the degree of difficulty(11.4%) were the next order. Conclusion: Based on the results of this study, the current dental technician did not show major problems in the practical test. However, clinicians should be strengthened mainly. To do this, the use of the articulator is essential.

• Journal of Technologic Dentistry
• /
• v.34 no.2
• /
• pp.121-128
• /
• 2012

Purpose: The aim of this study was to determine the reliability and accuracy of measurements in digital models(CEREC$^{(R)}$ AC) compared to stone models. Methods: A master model(500B-1, Nissin Dental Product, Japan) with the prepared upper full arch tooth was used. Conventional impression and then stone model(n=10) were produced from this master model, and on the other hands, digital impressions were made with the CEREC$^{(R)}$ AC intra-oral scanner(n=10). One examiner measured two times the intercanine, intermolar distance, dental arch length. The stone model were measured using a digital caliper. The t-student test for paired samples and intraclass correlation coefficient(ICC) were used for statistical analysis. Results: The measurement of two methods showed very good reliability. At the intra-examiner reliability of measurement, ICC at the stone and CEREC$^{(R)}$ AC model were 0.81 and 0.94. The mean difference between measurements made directly on the stone models and those made on the CEREC$^{(R)}$ AC model was 0.20~0.28mm, and was statistically significant(P=0.001). Conclusion: These in vitro studies show that accuracy of the digital impression is similar to that of the conventional impression. These results will have to be confirmed in further clinical studies.

• The korean journal of orthodontics
• /
• v.44 no.2
• /
• pp.69-76
• /
• 2014

Objective: This study aimed to evaluate the accuracy and precision of polyurethane (PUT) dental arch models fabricated using a three-dimensional (3D) subtractive rapid prototyping (RP) method with an intraoral scanning technique by comparing linear measurements obtained from PUT models and conventional plaster models. Methods: Ten plaster models were duplicated using a selected standard master model and conventional impression, and 10 PUT models were duplicated using the 3D subtractive RP technique with an oral scanner. Six linear measurements were evaluated in terms of x, y, and z-axes using a non-contact white light scanner. Accuracy was assessed using mean differences between two measurements, and precision was examined using four quantitative methods and the Bland-Altman graphical method. Repeatability was evaluated in terms of intra-examiner variability, and reproducibility was assessed in terms of interexaminer and inter-method variability. Results: The mean difference between plaster models and PUT models ranged from 0.07 mm to 0.33 mm. Relative measurement errors ranged from 2.2% to 7.6% and intraclass correlation coefficients ranged from 0.93 to 0.96, when comparing plaster models and PUT models. The Bland-Altman plot showed good agreement. Conclusions: The accuracy and precision of PUT dental models for evaluating the performance of oral scanner and subtractive RP technology was acceptable. Because of the recent improvements in block material and computerized numeric control milling machines, the subtractive RP method may be a good choice for dental arch models.

• Journal of dental hygiene science
• /
• v.15 no.2
• /
• pp.226-231
• /
• 2015

The purpose of this study was to evaluate the accuracy of model according to three types of dental scanner. A maxillary acrylic model was prepared and duplicated 10 times by silicone impression materials. Corresponding working casts were formed from scannable stone and got a 3-dimensional digital models using three different scanners. The distance of each measurement region was measured using vernier calipers and the respective program. One-way ANOVA and the Tukey honestly significant difference post hoc test (${\alpha}=0.05$) was performed using IBM SPSS Statistics 21.0. Overall, the stone cast is smaller than the digital models in measurement distance. And measuring point value of laser scanner showed the most similar values and measurement points value of digital vernier calipers. Digital model of white light scanner showed similar values in the measurement points value of the blue light scanner. In conclusion, the laser scanner showed the best accuracy among the three types of dental scanner. However, the difference between the digital models and the stone cast can be accommodated in making prostheses. Thereby, three types of dental scanner are available in a clinically acceptable range.

• Journal of Technologic Dentistry
• /
• v.34 no.4
• /
• pp.369-377
• /
• 2012

Purpose: The aim of study was to compare the dimensional stability of digitized dental stone replica using different color of gypsum materials using a white light scanner with three-dimensional software. Methods: A master model(500B-1, Nissin dental product, Japan) with the prepared lower full arch tooth was used. Several type IV stones(white, yellow, green) were used for 30 stone casts(10 casts each) duplicated a master model of mandible. The master model and the replicas were digitized with the non-contacting white light scanner to create 3-dimensional digital models. The linear distance between the reference points were measured and analyzed on the Delcam Copycad$^{(R)}$(Delcam plc, UK) 3D graphic software. One-way analysis of variance(ANOVA) combined with a Tukey multiple-range test were used to analysis the data(${\alpha}$=0.05). Results: There were considerable differences in mean values between gypsum materials within each color(white, yellow, green), and this difference was statistically significant, p=0.001. Conclusion: Digitization of dental materials on optical scanner was affected by color. Three different color of gypsum materials showed clinically acceptable accuracies of full arch digital model produced by them. Besides, these results will have to be confirmed in further clinical studies.

• The Journal of the Korean dental association
• /
• v.54 no.12
• /
• pp.985-995
• /
• 2016

Titanium (Ti) has been widely used for dental implant due to great biocompatibility and bonding ability against natural alveolar bone. A lot of titanium surface modification has been introduced in dentistry and, among them, methods to introduce micro/nano-roughened surface were considered as clinically approved strategy for accelerating osseointegration of Ti dental implant. To have synergetic effect with topography oriented favors in cell attachment, chair-side surface treatment with reproducibility of micro/nano-topography is introduced as next strategy to further enhance cellular functionalities. Extensive research has been investigated to study the potential of micro/nano-topography preserved chair-side surface treatment for Ti dental implant. This review will discuss ultraviolet, low level of laser therapy and non-thermal atmospheric pressure plasma on Ti dental implant with micro/nano-topography as next generation of surface treatment due to its abilities to induce super-hydrophilicity or biofunctionality without change of topographical cues.

• Journal of Technologic Dentistry
• /
• v.43 no.2
• /
• pp.69-69
• /
• 2021

• Journal of Sensor Science and Technology
• /
• v.21 no.3
• /
• pp.217-222
• /
• 2012

Optical coherence tomography(OCT) is a noninvasive optical imaging tool for biomedical applications. OCT can provide depth resolved two/three dimensional morphological images on biological samples. In this paper, we integrated an OCT system that was composed of an SLED(Superluminescent Light Emitting Diode, ${\lambda}_0$=1305 nm bandwith= 141 nm), a reference arm adopting a rapid scanning optical delay line(RSOD) to get high speed imaging, and a sample arm that used a micro electro mechanical systems(MEMS) scanning mirror. The sample arm contained a compact probe for imaging dental structures. The performance of the system was evaluated by imaging in-vivo human teeth with dental calculus, and the results indicated distinct appearance of dental calculus from enamel, gum or decayed teeth. The developed probe and system could successfully confirm the presence of dental calculus with a very high spatial resolution($6{\mu}m$).

• Journal of Technologic Dentistry
• /
• v.37 no.4
• /
• pp.191-197
• /
• 2015

Purpose: The purpose of this study was to compare the accuracy of the scan data acquired by the extra-oral and intra-oral scanner. Methods: The maxillary right first molar was made of polymethyl methacrylate(PMMA) specimen. This PMMA specimen was scanned with a engineering scanner and intra-oral scanner. Meanwhile, extra-oral scanner scanned stone die duplicated from PMMA master die. Trueness and precision of scan datas was measured by 3-dimensinal inspection. Independent t-test was conduct to analysis the significant difference(a=0.05). Results: In the trueness analysis, mean of discrepancies were 13.82um for intra oral scanner and 16.84 um for extra-oral scanner. In the precision analysis, mean of discrepancies were 11.72 for inta-oral scanner and 9.2 for extra-oral scanner. Both trueness and precision showed a statistically significant difference (Table 1, p<0.05). Conclusion: Intra-oral scanner can show higher trueness than extra-oral scanner, it has lower precision.