• The Journal of Korean Academy of Prosthodontics
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• v.27 no.2
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• pp.79-100
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• 1989

The Purpose of this study was to investigate material differences in stress transmission among various artificial teeth and denture base materials. For this study, a two-dimensional finite element model and a two-dimensional photoelastic model of a mandible with complete denture were made. A resin tooth and a porcelain tooth were used as artificial teeth, and a resin base, a metal lined base, and a soft-liner lined base were used as denture bases. An occlusal load was applied and principal stresses generated in the supporting tissues were compared. To test the impact stress transmission, strain gauge attached to the denture base specimens made of the different materials were made in thick and thin groups. Voltage outputs from hitting the specimen with a steel ball were compared. The results were as follows : 1. In FEM, increasing the mucosal thickness reduced the maximum principal stresses in the supporting tissues, but altering the tooth materials and the base materials induced no difference in the stresses. 2. In photoelastic model study, no difference in fringe order among the specimens were observed, but the thick mucosa group and the soft-liner lined group revealed a more uniform distribution of the load. 3. In strain measuring, the impact force transmission was highest in the soft-liner lined group, and was the lowest in the metal lined group(p<0.01). 4. In the thin group using the resin base, the porcelain tooth showed higher impact stress transmission than the resin tooth(p<0.01), but no difference was observed between them in the thick group. In the soft-liner lined group, the porcelain tooth showed higher impact stress transmission than the resin tooth(p<0.01), but no difference was observed between them in the metal lined group. 5. The thick group showed lower impact stress transmission than the thin group(p<0.01).

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.4
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• pp.313-320
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• 2002

The purpose of the present study was to evaluate the marginal discrepancy and topography of artificial crown on teeth extracted due to severe periodontal disease. Twenty specimens were invested into metamethylacrylate resin and cutted into vertical slices along with the long axis of tooth. The selected marginal discrepancy between the outer edge of the crown and the finishing line of abutment was examined by stereo- microscope(Olympus, PM-VSP-3, Japan) at magnification of up to 10, and the topography of finishing margin on crown was observed by stereomicroscopeat magnification of up to $70{\times}$. The results were as follows. (1) The mean marginal discrepancy between extracted tooth and artificial crown were $50.82{\mu}m$. (2) There was a considerable difference in the microstructure of finishing margins among specimens. Microscopic Structure on finishing margin showed indefinite line, poor fit (open, underextended and overextended), distorted margin, and surface roughness. This study suggested that there could be necessary to consider the response of periodontium to the emergence profile of natural tooth and precision of marginal geometry while establishing treatment planning for the reconsruction of the artificial crown.

• The Journal of Advanced Prosthodontics
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• v.8 no.6
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• pp.511-514
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• 2016

For patients with systemic diseases who face difficulties visiting dental clinics, wearing fixed partial denture in the anterior region on the same day of tooth extraction can reduce the total period of treatment and the number of visits, as well as post-treatment psychological effect on the patient.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.1
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• pp.12-18
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• 2020

Impacted teeth are a frequent phenomenon encountered by every clinician. The artificial eruption of embedded teeth is the process of directing an impacted tooth into normal occlusion. This procedure is currently attracting attention, with the aim of finding the best technique to use according to each case. This article presents key information regarding impacted incisors, canines, and premolars. In addition, we describe the most common techniques to use for artificial eruption, the open and closed techniques. We review the literature concerning these techniques and outline how clinicians can manage every type of impacted tooth.

• Journal of Technologic Dentistry
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• v.7 no.1
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• pp.33-40
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• 1985

When full denture is being fabricated, pronounciation, recovery of aesthetics of function and mastificatory function should be satisfies for patients. To satisfy for the function of denture, following is the difference between this new way of fabricating and formerly one of it. 1. The size of fabricating tooth which is harmony of original oral structure for patients is deaded by manufacturing labial index and artificial tongue. 2. By the use of artificial tongue and labial index, the arranges of artificial tooth is to become harmony of oral structure. 3. Formation of gingival decided functional impression which is used by impression paste, is harmony of oral structure. Therefore, this full denture can be satisfied with pronouncing oral function of recovery of aesthetics as well as mastificatory through physiological movement of oral tissue not disturbed with anything but cooperated drastically. In manufacturing of this full denture, both dentist and dental technician under cooperation need to proceed the work on the base of importance of communication.

• Journal of Technologic Dentistry
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• v.44 no.4
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• pp.154-160
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• 2022

The need for repairing removable dentures has grown as the population had aged. The direct methods allow existing dentures to be repaired without interrupting their use. However, if patient compliance is low, direct methods may be challenging. Moreover, attaching an artificial tooth to a metal base is a complicated procedure because it necessitates casting a retentive element and soldering it to a metal base. This clinical report describes how to add an artificial tooth to a metal base, reline denture bases, and reestablish occlusion on relined removable dentures using indirect methods. Existing removable dentures were successfully repaired and their service life was efficiently extended using the methods described.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.4
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• pp.465-473
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• 1999

Bond strength of luting cements to dentin is a critical consideration for success of complete cast crowns. This study was performed to evaluate the relationship between surface characteristics of teeth prepared for complete cast crowns and retention of cemented restorations. Eighty artificial crowns were cast for standardized complete crown tooth preparations accomplished with the use of a special device on recently extracted human teeth. Coarse diamond(#102R, Shofu) and superfine finishing diamond(#SF102R, Shofu) burs of similar shape were used. Crowns in each group were randomly subdivided into few subgroups of 10 for luting cements selected for this study: zinc phosphate cement (FLECK' S), polycarboxylate cement (Poly-F), rein-forced glass ionomer cement (Fuji PLUS). and adhesive resin cement (Panavia 21). Retention was evaluated by measuring the tensile load required to dislodge the artificial crown from tooth preparations with an Instron testing machine, and analysed by one-way ANOVA and Student's t-test. The obtained results were as follows ; 1. When tooth preparation was done with coarse diamond bur, retentive force was diminished in order of Panavia 21 Fuji PLUS, FLECK'S, and Poly-F. Retentive forces showed the significant difference between Fuji PLUS group and FLECK'S group(p<0.001). 2. When tooth preparation was done with superfine diamond bur, retentive force was diminished in order of Fuji PLUS, Panavia 21, FLECK'S, and Poly-F. Retentive forces showed the significant difference between Panavia 21 group and FLECK'S group(p<0.001). 3. Retentive force in coarse tooth surfaces was significantly higher than that in superfine tooth surface with all luting cements(p<0.001), and cement residues were almost retained with-in the cast crown in all groups.

• Imaging Science in Dentistry
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• v.53 no.4
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• pp.271-281
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• 2023

Purpose: The objective of this scoping review was to investigate the applicability and performance of various convolutional neural network (CNN) models in tooth numbering on panoramic radiographs, achieved through classification, detection, and segmentation tasks. Materials and Methods: An online search was performed of the PubMed, Science Direct, and Scopus databases. Based on the selection process, 12 studies were included in this review. Results: Eleven studies utilized a CNN model for detection tasks, 5 for classification tasks, and 3 for segmentation tasks in the context of tooth numbering on panoramic radiographs. Most of these studies revealed high performance of various CNN models in automating tooth numbering. However, several studies also highlighted limitations of CNNs, such as the presence of false positives and false negatives in identifying decayed teeth, teeth with crown prosthetics, teeth adjacent to edentulous areas, dental implants, root remnants, wisdom teeth, and root canal-treated teeth. These limitations can be overcome by ensuring both the quality and quantity of datasets, as well as optimizing the CNN architecture. Conclusion: CNNs have demonstrated high performance in automated tooth numbering on panoramic radiographs. Future development of CNN-based models for this purpose should also consider different stages of dentition, such as the primary and mixed dentition stages, as well as the presence of various tooth conditions. Ultimately, an optimized CNN architecture can serve as the foundation for an automated tooth numbering system and for further artificial intelligence research on panoramic radiographs for a variety of purposes.

• Journal of Technologic Dentistry
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• v.46 no.1
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• pp.8-14
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• 2024

Purpose: This study compares the deformation of traditional resin dentures to resin dentures printed with digital light processing (DLP). Methods: Eleven edentulous research models were developed. Ten of them were made with traditional resin dentures. The remaining one was prepared for scanning and 3D (three-dimensional) printing. Ten traditional resin dentures were made, with the remaining artificial teeth created using 3D software and a DLP printer. Traditional resin dentures, 3D printed resin denture artificial teeth, and a denture base with artificial teeth were all cleaned simultaneously in an ultrasonic cleaner for 3 minutes. Three groups were assigned four artificial tooth measurement points, which were then measured with digital calipers. The measured data was analyzed using descriptive statistics. The significance test was conducted using a nonparametric test Kruskal-Wallis test due to the small number of specimens (α=0.05). Results: The traditional resin dentures had the lowest strain rate at -0.04%, while the group that manufactured only artificial teeth had the highest strain rate at -0.09%. However, no statistically significant difference was observed between the 3 groups (p>0.05). Conclusion: During ultraviolet-type ultrasonic cleaning, traditional resin dentures (TD group) and denture base with artificial teeth made of DLP (DD group) demonstrated stable durability, whereas the artificial teeth made of DLP (AD group) with only artificial teeth did not show a good deformation rate.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.5
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• pp.375-379
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• 2011

Introduction: This study examined the effect of autogenous tooth bone used as a graft material for bone regeneration in an artificial bony defect of minipigs. Materials and Methods: Four healthy minipigs, weighing approximately 35-40 kg, were used. Four standardized artificial two-walled bony defects, 5 mm in length and depth, were made on the bilateral partial edentulous alveolar ridge on the mandible of minipigs, and autogenous tooth bone was augmented in the right side as the experimental group. On the other hand, only alloplastic bone graft material HA was grafted with the same size and manner in the left side as the control group. All minipigs were sacrificed at 4 weeks after a bone graft and evaluated histologically by Haematoxylin-eosin staining. The specimens were also evaluated semi-quantitatively via a histomorphometric study. The percentage of new bone over the total area was evaluated using digital software for an area calculation. Results: All specimens were available but one in the left side (control group) and two in the right side (experimental group) were missing during specimen preparation. The amount of bone formation and remodeling were higher in all experimental groups than the control. The mean percentage area for new bone in the experimental and control groups was $43.74{\pm}11.96%$ and $30.79{\pm}2.93%$, respectively. Conclusion: Autogenous tooth bone is a good alternative to autogenous bone with the possible clinical feasibility of an autogenous tooth bone graft in the reconstruction of bony defects.