No abstract available.
Tooth, Artificial*

This study was designed to investigate the stress distribution, intensity and force mechanism derived from the MEAW by photoelastic stress analysis of the artificial teeth and surrounding bone composed of photoelastic(material/ PL-3 ). The findings of this study were as follows: 1. In case of no elastic on the MEAW with tip back, the moderate stress was observed on the molar and canine area, and the light stress was observed on the other area. 2. In case of the vertical elastic on the plain A.W. and the MEAW without tip back, the great stress was observed on the lateral incisor area, but on the MEAW with tip back, the moderate stress was observed on the anterior area and molar area. 3. In case of the C II elastic on plain A.W., the stress was concentrated on the anterior area hanged by elastic but on the MEAW without tip back, the stress was transmitted equally from the anterior area to the posterior teeth area, On the MEAW with tip back, the great stress was observed on the anterior and molar area. 4. In case of the C III elastic on the plain A.W., the stress was concentrated on the posterior area hanged by elastic but on the MEAW without tip back, the stress was transmitted equally from the posterior area to the anterior area. On the MEAW with tip back, the great stress was observed on the posterior area and the moderate stress was observed on the anterior area.
Incisor ; Molar ; Tooth ; Tooth, Artificial

PURPOSE: The purpose of this study was to analyze and estimate whether each company may produce the color of artificial teeth as it stands, in the standard of vita classical shade guide using ShadeScan(TM) System. MATERIAL AND METHODS: we chose the products of 6 companies -EFUCERA, IVOCLAR, ENDURA, TRUBYTE, DURADENT, and DURACROSS- estimated the shade value of each fixed point(cervical, body, and incisal area) of artificial tooth, and verified the equality among the samples from the same company. RESULTS: First, the variation appeared significant at cervical and incisal area. It means that there were significant differences between cervical and incisal area although the most similar artificial teeth to the patients' natural teeth were provided. Second, the results in the body area showed that the variation between artificial and natural teeth was finite(p<0.05) in that area. CONCLUSION: it shows that the reproduction of colors of artificial teeth might be successful regarding the body is the most important part for a determination of the color of artificial teeth. However, more complements are necessary for the better reproduction of the color of artificial teeth between cervical and incisal area.
Complement System Proteins ; Reproduction ; Tooth ; Tooth, Artificial*

OBJECTIVE: The aim of this study was to compare the differences in closing extraction spaces between maxillary first premolar and second premolar extractions using 3-dimensional finite element analysis (FEA). METHODS: Maxillary artificial teeth were selected according to Wheeler's dental anatomy. The size and shape of each tooth, bracket and archwire were made from captured real images by a 3D laser scanner and FEA was performed with a 10-noded tetrahedron. A 10 degrees gable bend was placed behind the bull loop on a 0.017" x 0.025" archwire. The extraction space was then closed through 12 repeated activating processes for each 2 mm of space. RESULTS AND CONCLUSIONS: The study demonstrated that the retraction of anterior teeth was less for the second premolar extraction than for the first premolar extraction. The anterior teeth showed a controlled tipping movement with slight extrusion, and the posterior teeth showed a mesial-in rotational movement. For the second premolar extraction, buccal movement of posterior teeth was highly increased.
Bicuspid* ; Finite Element Analysis* ; Tooth ; Tooth, Artificial

OBJECTIVETo get the information of patients' understand to the knowledge of artificial teeth prosthetics, provide reference for the propaganda of the prosthetic knowledge.

METHODS500 patients were chosen as the research objects. The survey about patients' understand to the knowledge of artificial teeth prosthetics was made with a reasonable questionnaire designed by us. The questionnaire contained nine sections. The questionnaires were filled in by the patients, dispatched and received by special messengers. The information of the questionnaires was analyzed and summarized.

RESULTS477 effective questionnaires were received. Patients were more familiar with the knowledge of the opportunity to get the oral prosthetic and less familiar with the knowledge of common problems after the oral prosthetic, the curing process before the oral prosthetic and the visiting times of the ordinary cure. However, they were not familiar with the knowledge of the basic concepts of the oral prosthetic, prosthetic materials and construction of dental prosthetic restoration and announcements after the oral prosthetic. They were most unfamiliar with the knowledge of common problems in the oral prosthetic process.

CONCLUSIONThe propaganda of the oral prosthetic should focus on the basic concepts of the oral prosthetic, prosthetic materials and construction of dental prosthetic restoration, common problems in the oral prosthetic process and announcements after the oral prosthetic. Meeting such problems, dentists should explain them to the patients patiently.

PURPOSE: The aim of this study was to evaluate the volumetric change of teeth after preparation for various designs and margin locations through Micro CT analysis (Skyscan 1076: SKYSCAN, Konitch, Belgium). MATERIALS AND METHODS: The 36 artificial teeth were used to determine reduction volume of upper central incisor. According to the restorative design these 36 teeth were divided into 4 groups and according to the marginal location each group was divided into 3 subgroups. The volume of unprepared teeth was obtained by using Micro CT and the volume of prepared teeth was obtained in the same method. The CT scanned images before and after preparation were superimposed. RESULTS: The volume difference was significantly increased as follows: traditional laminate veneer < full laminate veneer < all ceramic crown < metal ceramic crown. One-way ANOVA and Tukey multiple comparison analyses were used to analyze the data in this study. In each group the volume difference was significantly increased as follows: 1 mm above CEJ < CEJ < 1 mm below CEJ (P<.05). The % volume difference of all ceramic crown and metal ceramic crown was 31 - 48% and that of laminate veneer was 14 - 30%. The volume difference of the traditional laminate veneer was 1/3 of that of metal ceramic crown. The full laminate (1 mm below CEJ) and all ceramic crown (1 mm above CEJ) showed a similar volume difference. Metal ceramic crown showed 13.7 % more volume difference than all ceramic crown. CONCLUSION: There exists the difference in volumetric change according to designs of restoration and margin locations of preparation.
Ceramics ; Crowns ; Incisor ; Tooth ; Tooth Cervix ; Tooth, Artificial

No abstract available.
Denture, Complete* ; Finite Element Analysis* ; Tooth, Artificial*

OBJECTIVE: We evaluated the effects of tooth displacement on frictional force when conventional ligating lingual brackets (CL-LBs), CL-LBs with a narrow bracket width, and self-ligating lingual brackets (SL-LBs) were used with initial leveling and alignment wires. METHODS: CL-LBs (7th Generation), CL-LBs with a narrow bracket width (STb), and SL-LBs (In-Ovation L) were tested under three tooth displacement conditions: no displacement (control); a 2-mm palatal displacement (PD) of the maxillary right lateral incisor (MXLI); and a 2-mm gingival displacement (GD) of the maxillary right canine (MXC) (nine groups, n = 7 per group). A stereolithographic typodont system and artificial saliva were used. Static and kinetic frictional forces (SFF and KFF, respectively) were measured while drawing a 0.013-inch copper-nickel-titanium archwire through brackets at 0.5 mm/min for 5 minutes at 36.5℃. RESULTS: The In-Ovation L exhibited lower SFF under control conditions and lower KFF under all displacement conditions than the 7th Generation and STb (all p < 0.001). No significant difference in SFF existed between the In-Ovation L and STb for a 2-mm GD of the MXC and 2-mm PD of the MXLI. A 2-mm GD of the MXC produced higher SFF and KFF than a 2-mm PD of the MXLI in all brackets (all p < 0.001). CONCLUSIONS: CL-LBs with narrow bracket widths exhibited higher KFF than SL-LBs under tooth displacement conditions. CL-LBs and ligation methods should be developed to produce SFF and KFF as low as those in SL-LBs during the initial and leveling stage.
Friction* ; Incisor ; Ligation ; Saliva, Artificial ; Tooth*

Dental dysplasia are abnormalities in teeth structure, morphology, number and eruption caused by genetic and environmental factors during dental development. Digital medical techniques, as the current hot spot of medical research, bring great challenges and opportunities to modern stomatology. The applications of digital techniques, such as digital diagnosis method, digital virtual simulated design, three-dimensional printing, static and dynamic guidance and artificial intelligence, can provide a more accurate, efficient, automatic and intelligent modern concepts and patterns for epidemiology, diagnosis, multidisciplinary treatment and outcome assessment of dental developmental anomalies.
Artificial Intelligence ; Printing, Three-Dimensional ; Tooth

PURPOSE: The accuracy of a gypsum model (GM), which was taken using a conventional silicone impression technique, was compared with that of a polyurethane model (PM), which was taken using an iTero(TM) digital impression system. MATERIALS AND METHODS: The maxillary first molar artificial tooth was selected as the reference tooth. The GMs were fabricated through a silicone impression of a reference tooth, and PMs were fabricated by a digital impression (n=9, in each group). The reference tooth and experimental models were scanned using a 3 shape convince(TM) scan system. Each GM and PM image was superimposed on the registered reference model (RM) and 2D images were obtained. The discrepancies of the points registered on the superimposed images were measured and defined as GM-RM group and PM-RM group. Statistical analysis was performed using a Student's T-test (alpha=0.05). RESULTS: A comparison of the absolute value of the discrepancy revealed a significant difference between the two groups only at the occlusal surface. The GM group showed a smaller mean discrepancy than the PM group. Significant differences in the GM-RM group and PM-RM group were observed in the margins (point a and f), mesial mid-axial wall (point b) and occlusal surfaces (point c and d). CONCLUSION: Under the conditions examined, the digitally fabricated polyurethane model showed a tendency for a reduced size in the margin than the reference tooth. The conventional gypsum model showed a smaller discrepancy on the occlusal surface than the polyurethane model.
Calcium Sulfate* ; Models, Theoretical ; Molar ; Polyurethanes* ; Silicones ; Tooth ; Tooth, Artificial