Full-mouth rehabilitation of a patient with severe wear using digital facebow transfer and virtual articulator / 대한치과보철학회지

The progressive wear of teeth is a physiologic process of aging, but excessive wear can lead to occlusal disharmony, tooth sensitivity and pulp exposure, decreased masticatory efficiency, and aesthetic problems. It should be treated by evaluating the cause of tooth wear and establishing a stable centric relation with appropriate vertical dimension of occlusion and occlusal plane. The present case report successfully rehabilitated a full-mouth case of a severely worn dentition with the use of digital facebow transfer and virtual articulator.

Full-mouth rehabilitation of severely attrited dentition with missing posterior teeth: a case report using digital workflow with jaw motion tracking / 대한치과보철학회지

Jaw motion tracking, which is introduced in recent case reports, is a method which records the patient’s individualized pathway of the mandibular movements along with facebow transfer, and reproduces the information in the virtual space of computer-aided-design/computer-aided-manufacturing (CAD-CAM) software.In this present case, a collapse of the occlusal plane was observed, due the loss of posterior teeth for a long period. Full-mouth rehabilitation with an increase in the occlusal vertical dimension was planned. First, the patient’s mandibular movements were recorded on the newly established jaw relation by jaw tracking, and this information was assembled with the patient’s intraoral data to create a virtual patient. Implant planning and diagnostic wax-up was done on the virtual patient, leading the fabrication of the provisional prosthesis. On the newly established jaw relation with an increase in the occlusal vertical dimension, canine guidance of the provisional prosthesis was checked. Finally, the provisional prosthesis was carried out to the definitive prosthesis. Using the advantages of the technologies in the digital dentistry, the patient was satisfied with the function and the esthetics after the treatment.

Full mouth rehabilitation in partially edentulous patient with an unstable mandibular position / 대한치과보철학회지

In the case of a patients who have lost the centric stop and have a staggered occlusion of the residual teeth, various movements occur when the denture is loaded.Implant placement is necessary to reinforce the retention, support, and stabilization elements to reduce denture movement. However, in this case, considering the patient’s age, aversion to surgery, and bone loss, implants were not placed and restoration was performed with a removable partial denture. In this case, it is important to set the correct mandibular position for restoration because the patient has a habit of chewing with the remaining teeth. In this case, a stable mandibular position was established using a gothic arch tracing, and good results were obtained by restoring with partial dentures, so this is reported.

‘All-on-4’ fixed implant supported prosthesis restoration using digital workflow: a case report / 대한치과보철학회지

In the case of fully edentulous patients with severe alveolar bone resorption, the consideration of ‘All-on-X’ implant-supported fixed prosthesis after placing four or more implants in the anterior maxilla is possible. Recent advancements in digital dentistry have enabled systematic and predictable treatment in all phases, including diagnosis, surgery, and prosthesis fabrication. By incorporating digital dentistry techniques such as digital complete denture, implant surgical guides, facial scanning into the conventional restoration process, it is possible to reduce the complexity of the prosthesis fabrication and effectively achieve the transition from provisional prosthesis to definitive prosthesis in terms of both aesthetics and function.

3-step digital complete denture restoration using facialscan: a case report / 대한치과보철학회지

Support, retention, and stability of dentures are key factors in the use of complete dentures in edentulous patients. With the development of digital dentistry, attempts are being made to replace traditional treatment methods. Also, struggle to reduce the number of patient visits and to manufacture high-quality digitally fabricated dentures are ongoing. In this case, a digital denture was restored using a tray capable of obtaining centric relation through gothic arch tracing and a facial scan. By replacing the traditional complete denture restoration method, the number of patient visits was reduced and esthetic results with satisfactory denture support, retention, and stability were obtained.

Maxillary overdenture restoration using functionally generated path technique: a case report / 대한치과보철학회지

The functionally generated path (FGP) technique, first described by Meyer in 1933, is a method in the oral cavity to use the movement pathway formed by the opposing cusps within the border movement of the mandible. Using this method, an appropriate occlusal shape can be given to the patient. In this case, the FGP technique was selected to provide a bilateral balanced occlusion when restoring the edentulous maxilla that opposes the natural mandibular teeth with irregular arrangement with overdentures. In addition, in order to precisely form the occlusal surface of the posterior region with the FGP technique and to reduce the attrition of denture teeth, zirconia denture teeth, not conventional resin artificial teeth, were individually manufactured. After treatment with these materials and methods, satisfactory results were obtained for both the operator and the patient.

Maxillary complete denture rehabilitation in flabby tissue patient considering of function and stability: A clinical report / 대한치과보철학회지

It is very difficult to achieve denture support, stability and retention in single-maxillary complete denture patients with flabby tissue. A 57-year-old male patient was uncomfortable with the existing denture and wanted treatment. The reduction of flabby tissue was confirmed using the treatment denture. Non-pressure impression was obtained using an intraoral scanner during the definitive denture process. This is reported because the resulting denture improved when observing the retention, support and stability of the denture during occlusion.

Using 3-dimensional digital smile design in esthetic restoration of anterior teeth: A case report / 대한치과보철학회지

Currently, digital technology is being used in various fields of dental treatment. In particular, in the case of anterior esthetic restoration, the traditional restoration method cannot contain facial information and it is difficult for the patient to predict the treatment result. However, in the case of esthetic restoration through digital design, the visualization of the prosthesis design and the ease of reflecting patient feedback, and expecting the treatment result is available. In this case, the patient confirmed the results of restoration treatment using a digital method before treatment and obtained consent for treatment in an anterior tooth trauma patient. In addition, since the conventional digital smile design method uses only the patient’s facial and smile information, the design was made on a two-dimensional plane, and its application was somewhat limited. However, in this case, a three-dimensional virtual patient was created and thus the designed restoration was viewed from various angles. Through this case, it was possible to obtain a high degree of satisfaction with the ease of communication with the patient and the technician during the esthetic restoration using the digital method, the simplicity of the procedure, and the treatment result.

Restoration of anterior teeth with dental implant using multilayer zirconia / 대한치과보철학회지

For successful restoration of maxillary anterior implants, both pink esthetics and white esthetics must be satisfied. For pink esthetic part, the role of appropriate provisional prosthesis restoration is important, and for white esthetic part, the color and shape of the definitive prosthesis is important. Multilayer zirconia can be used for natural tooth appearance due to the higher transparency of the incisal area compared to the conventional monolithic zirconia. Therefore, in this case, white esthetic part was achieved through multilayer zirconia after recovering function and esthetics through appropriate provisional prosthesis in a patient who lost the maxillary anterior teeth.

Full mouth rehabilitation for a patient with vertical dimension loss using digital diagnostic analysis: A clinical report / 대한치과보철학회지

Full mouth rehabilitation is re-organizing the occlusion of the remaining teeth and missing teeth considering the functions, esthetics, and neuromuscular harmony. With the loss of multiple teeth, the patient’s occlusal plane gradually collapses and the vertical dimension can be reduced. Since reduced vertical dimension can be a potential etiology of the temporomandibular joint and masticatory muscles, prosthetic restoration with increased vertical dimension is required. This case report is about a 68 years old patient with vertical dimension loss due to worn dentition and multiple loss of teeth. In this case, the loss of vertical dimension is assessed carefully using the digital dentistry technology. Using CAD software in digital analysis step, the occlusal plane was established and evaluated using several criteria. Orienting the position of the bone and teeth using CBCT image, patient’s condition was visualized in 3 dimension and treatment planning was possible virtually. The information that matches the patient’s condylar position with the articulator, which is the virtual face bow, is reproduced on the actual articulator, and evaluated again. After the evaluation, provisional prosthesis was fabricated and it was confirmed that the patient adapts without any abnormality. This was implemented as a final prosthesis. As a result, the patient obtained satisfying results, utilizing the benefits of digital dentistry technology and traditional methods.

Comparative study of volumetric change in water-stored and dry-stored complete denture base / 대한치과보철학회지

Purpose@#Generally, patients are noticed to store denture in water when removed from the mouth. However, few studies have reported the advantage of volumetric change in underwater storage over dry storage. To be a reference in defining the proper denture storage method, this study aims to evaluate the volumetric change and dimensional deformation in case of underwater and dry storage. Materials and @*methods@#Definitive casts were scanned by a model scanner, and denture bases were designed with computer-aided design (CAD) software. Twelve denture bases (upper 6, lower 6) were printed with 3D printer. Printed denture bases were invested and flasked with heat-curing method. 6 upper and 6 lower dentures were divided into group A and B, and each group contains 3 upper and 3 lower dentures. Group A was stored dry at room temperature, group B was stored underwater. Group B was scanned at every 24 hours for 28 days and scanned data was saved as stereolithography (SLA) file. These SLA files were analyzed to measure the difference in volumetric change of a month and Kruskal-Wallis test were used for statistical analysis. Best-fit algorithm was used to overlap and 3-dimensional color-coded map was used to observe the changing pattern of impression surface. @*Results@#No significant difference was found in volumetric changes regardless of the storage methods. In dry-stored denture base, significant changes were found in the palate of upper jaw and posterior lingual border of lower jaw in direction away from the underlying tissue, maxillary tuberosity of upper jaw and retromolar pad area of lower jaw in direction towards the underlying tissue. @*Conclusion@#Storing the denture underwater shows less volumetric change of impression surface than storing in the dry air.

Relationship between usage of removable denture and depression in Korean adults with loss of multiple teeth:A cross-sectional study using the seventh Korea National Health and Nutrition Examination Survey / 대한치과보철학회지

Purpose@#The purpose of this study is to evaluate the relationship between removable denture and depression. This study aims to investigate the relationship between depression and each group by dividing them into a group that were using removable dentures and a group that needed removable dentures but were not using removable dentures. Materials and @*methods@#This study was conducted using raw data from the 7th Korea National Health and Nutrition Examination Survey (KNHNES). By using variables related to the state of the prosthesis and the need for prosthesis among oral examination data, the oral examination data were classified into two groups; group using removable denture and group in need of removable dentures. In addition, the variables of depression were classified into normal (0-4), mild depression (5-9), moderate depression (10-19), and severe depression (20-27) using the values of PHQ-9. For statistical analysis, logistic regression analysis was performed using SAS 9.4. @*Results@#In the group in need of removable dentures, the risk of severe depression was statistically and significantly higher than the group using removable dentures. @*Conclusion@#In patient who have lost multiple teeth, rehabilitation of the missing area with removable dental prosthesis is expected to decrease the occurrence of severe depression.

Accuracy of implant digital scans with different intraoral scanbody shapes and library merging according to different oral exposure height / 대한치과보철학회지

Purpose@#The purpose of this study is to compare the accuracy of digital scans of implants according to different shapes of scanbodies, and to compare the accuracy of library merging according to different oral exposure height. @*Materials and methods@#A master model with a single tooth edentulous site was prepared. For the first experiment, three types of intraoral scanbodies were prepared, divided into three groups, and the following experiments were conducted for each group: An internal hex implant was placed. The master model with the scanbody connected was scanned with a model scanner, and a master reference file (control group) was created. 10 files (experimental group) were created by performing 10 consecutive scans with an intraoral scanner. After superimposing the control and experimental groups, the following values were calculated: 1) Distance deviation of a designated point on the scanbody 2) Angle deviation of the major axis of the scanbody. For the second experiment, the scanbody scan data were prepared in 6 different heights. Library files were merged with each of the scan data. The distance and angular deviation were calculated using the 7 mm scan data as control group. @*Results@#In the first experiment, there were no significant differences between A and B (P=.278), B and C (P=.568), and C and A (P=.711) in the distance deviations. There were no significant differences between A and B (P=.568), B and C (P=.546), and C and A (P=.112) in the angular deviations. Also, the scanbody showed significantly higher library merging accuracy in the groups with high oral exposure height (P<.5). @*Conclusion@#There were no significant differences in scan accuracy according to the different shapes of scanbodies, and the accuracy of library merging increased according to exposure height of the scanbody in the oral cavity.

Effect of surface treatment on shear bond strength between artificial resin teeth and 3D printing denture base resin / 대한치과보철학회지

Purpose@#The purpose of this study is to compare the shear bond strength of 3D printing denture base resin according to surface treatment of artificial teeth. @*Materials and methods@#3D printing denture base resin was fabricated as specimens using 3D printer. The experimental group divided the surface treatment of artificial teeth into five groups according to the application of sandblasting and primer (n=10). Shear bond strengths between denture base and artificial teeth were measured by universal testing machine. All measurements were analyzed by one-way ANOVA and Turkey test (α=.05). Fracture mode of each specimen was analyzed. Microscopic evaluation was conducted by using a scanning electron microscope. @*Results@#Unsurfaced treated group represented the lowest value. The primer groups had significantly higher result values (P<.05). Most specimens of the primer groups had cohesive failure. @*Conclusion@#In 3D printing denture base resin group, mechanical and chemical surface treatment of artificial teeth has increased the shear bond strength. Therefore, if dentures are produced using 3D printing, proper mechanical and chemical treatment of artificial teeth is necessary for adhesion of dentures and artificial teeth.

A novel retentive type of dental implant prosthesis: marginal fitness of the cementlessdouble crown type implant prosthesis evaluated by bacterial penetration and viability

. This study aims to compare the marginal fitness of two types of implant-supported fixed dental prosthesis, i.e., cementless fixation (CL.F) system and cement-retained type. MATERIALS AND METHODS. In each group, ten specimens were assessed. Each specimen comprised implant lab analog, titanium abutment fabricated with a 2-degree tapered axial wall, and zirconia crown. The crown of the CL.F system was retained by frictional force between abutment and relined composite resin. In the cement-retained type, zinc oxide eugenolcement was used to set crown and abutment. All specimens were sterilized with ethylene oxide, immersed in Prevotella intermedia culture in a 50 mL tube, and incubated with rotation. After 48 h, the specimens were washed thoroughly before separating the crown and abutment. The bacteria that penetrated into the crownabutment interface were collected by washing with 500 μL of sterile saline. The bacterial cell number was quantified using the agar plate count technique. The BacTiter-Glo Microbial Cell Viability Assay Kit was used tomeasure bacterial adenosine triphosphate (ATP)-bioluminescence, which reflects the bacterial viability. The t-test was performed, and the significance level was set at 5%. RESULTS. The number of penetrating bacterial cells assessed by colony-forming units was approximately 33% lower in the CL.F system than in the cement-retained type (P<.05). ATP-bioluminescence was approximately 41% lower in the CL.F system than in the cementretained type (P<.05). CONCLUSION. The CL.F system is more resistant to bacterial penetration into theabutment-crown interface than the cement-retained type, thereby indicating a precise marginal fit.

Comparing accuracy of denture bases fabricated by injection molding, CAD/CAM milling, and rapid prototyping method

PURPOSE: The accuracy of denture bases was compared among injection molding, milling, and rapid prototyping (RP) fabricating method. MATERIALS AND METHODS: The maxillary edentulous master cast was fabricated and round shaped four notches were formed. The cast was duplicated to ten casts and scanned. In the injection molding method, designed denture bases were milled from a wax block and fabricated using SR Ivocap injection system. Denture bases were milled from a pre-polymerized block in the milling method. In the RP method, denture bases were printed and post-cured. The intaglio surface of the base was scanned and surface matching software was used to measure inaccuracy. Measurements were performed between four notches and two points in the mid-palatal suture to evaluate inaccuracy. The palatine rugae resolution was evaluated. One-way analysis of variance was used for statistical analysis at α=.05. RESULTS: No statistically significant differences in distances among four notches (P>.05). The accuracy of the injection molding method was lower than those of the other methods in two points of the mid-palatal suture significantly (P < .05). The degree of palatine rugae resolution was significantly higher in the injection molding method than that in other methods (P < .05). CONCLUSION: The overall accuracy of the denture base is higher in milling and RP method than the injection molding method. The degree of fine reproducibility is higher in the injection molding method than the milling or RP method.

Utilization of digital technology in fabricating mandibular implant overdenture for skeletal class II edentulous patient: A case report / 대한치과보철학회지

Unlike class I patients, skeletal class II patients have unstable occlusion thus leading to instability of mandibular complete denture. Therefore, mandibular implant overdenture has been the standard of care due to its advantages in stability and retention. The types of attachments can be divided into two categories: solitary and bar type. The indications vary between two categories. In this clinical report, digital technology was utilized from the implant planning to the choice of appropriate attachment. Implants were placed at the desired location as previously planned in terms of angle and depth. Maxillary removable partial denture and mandibular implant overdenture are expected to have fair prognosis.

Rehabilitation of fully edentulous patient using Ceramill full denture system (FDS) / 대한치과보철학회지

CAD/CAM technology has already been used in most areas of prosthetics. The range of CAD/CAM application in denture fabricating process has been gradually increasing since the CAD/CAM technology was introduced for the fabrication of complete dentures in 1994. This paper describes a technique that combines conventional and CAD/CAM technology for the fabrication of complete dentures: the master casts from a conventional impression techniques were scanned first, and the wax denture was fabricated using Amann Girrbach's Ceramill full denture system (fds). The purpose of this paper is to introduce the case in which making an esthetically and functionally satisfied denture in shorter time is possible with CAD/CAM technology.

Full mouth rehabilitation of patient with severe dental caries with implant fixed prosthesis fabricated with milling and 3D printing method: A case report / 대한치과보철학회지

Passive fit of prosthesis is an essential property of implant supported prosthesis for long term success and minimization of complications. And the property is determined mostly by fabrication procedure. There were limitations of extensive implant prosthesis because conventional casting method generate contraction error of long span prosthesis. However, Computer-aided design/Computer-aided manufacturing (CAD/CAM) technology of 3D printing and milling metal framework can overcome those limitations. This case is a full mouth rehabilitation using extensive implant fixed prosthesis. Removable interim prosthesis was made for esthetic, functional evaluation and a guide for implant insertion. After the insertion, implant fixed interim prosthesis was delivered. After additional evaluation and adjustment, final prosthesis was designed with CAD, the fabricated with CAM. Milling technique was used for anterior screw type implant superstructure and 3D printing technique was used for the anterior and posterior implant copings. Fit of the final restoration was favorable. The practitioner and patient were both esthetically and functionally satisfied with the final result.

Effects of cementless fixation of implant prosthesis: A finite element study

PURPOSE: A novel retentive type of implant prosthesis that does not require the use of cement or screw holes has been introduced; however, there are few reports examining the biomechanical aspects of this novel implant. This study aimed to evaluate the biomechanical features of cementless fixation (CLF) implant prostheses.MATERIALS AND METHODS: The test groups of three variations of CLF implant prostheses and a control group of conventional cement-retained (CR) prosthesis were designed three-dimensionally for finite element analysis. The test groups were divided according to the abutment shape and the relining strategy on the inner surface of the implant crown as follows; resin-air hole-full (RAF), resin-air hole (RA), and resin-no air hole (RNA). The von Mises stress and principal stress were used to evaluate the stress values and distributions of the implant components. Contact open values were calculated to analyze the gap formation of the contact surfaces at the abutment-resin and abutment-implant interfaces. The micro-strain values were evaluated for the surrounding bone.RESULTS: Values reflecting the maximum stress on the abutment were as follows (in MPa): RAF, 25.6; RA, 23.4; RNA, 20.0; and CR, 15.8. The value of gap formation was measured from 0.88 to 1.19 µm at the abutmentresin interface and 24.4 to 24.7 µm at the abutment-implant interface. The strain distribution was similar in all cases.CONCLUSION: CLF had no disadvantages in terms of the biomechanical features compared with conventional CR implant prosthesis and could be successfully applied for implant prosthesis.