• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.4
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• pp.186-198
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• 2021

As the increased certainty of osseointegration, new parameters are now being used to assess implant success. Accordingly, patients' and clinicians' high demands and expectation for esthetics have expanded and implant-supported restorations show better esthetic outcomes. The pre-implant treatment planning process, the implant surgical steps and the post-surgery prosthetic process can affect all esthetic outcomes. Prevention of esthetic implant failures can be achieved by appropriate treatment at each stage, considering the 3 factors of alveolar bone, soft tissue, and implants. It is necessary to achieve the esthetic implant prostheses followings: minimal invasive surgery, bone augmentation, ideal 3-dimensional implant position, peri-implant soft tissue management, and provisional restorations to optimize peri-implant soft tissue architecture.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.1
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• pp.51-61
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• 2011

Recently, restoring implants in the esthetically demanding region, zirconia-based materials are widely used due to their superior mechanical properties, accuracies, and esthetics. The purpose of this study was to investigate the load transfer and mechanical stability of zirconia and titanium implant abutments by using the three-dimensional finite element analysis model. The internal conical joint type and external butt joint type implant system was selected as an experimental model. Finite element models of bone/implant/prosthesis complex were constructed. An load of 250N was applied vertically beside 3mm of implant axis. Stress distribution of zirconia and titanium implant abutment is similar. The maximum equivalent stress of titanium implant abutment is lower than zirconia implant abutment about 15%. Howevere considering a high mechanical strength that exceed those of titanium implant abutment, zirconia implant abutment had similar mechanical stability of titanium implant abutment clinically.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.2
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• pp.105-113
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• 2018

Purpose: The purpose of this study was to investigate the effects of the insertion depth of an immediately loaded implant on the stress distribution of the surrounding bone and the micromovement of the implant using the three-dimensional finite element analysis. Materials and methods: A total of five bone models were constructed such that the implant platform was positioned at the levels of 0.00 mm, 0.25 mm, 0.50 mm, 0.75 mm, and 1.00 mm depth from the crest of the cortical bone. A frictional coefficient of 0.3 and the insertion torque of 35 Ncm were simulated on the interface between the implant and surrounding bone. A static load of 178 N was applied to the provisional prosthesis with a vertical load in the axial direction and an oblique load at $30^{\circ}$ with respect to the central axis of the implant, then a finite element analysis was performed. Results: The implant insertion depth significantly affected the stress distribution on the surrounding bone. The largest micromovement value of the implant was $39.34{\mu}m$. The oblique load contributed significantly to the stress distribution and micromovement in comparison to the vertical load. Conclusion: Increasing the implant insertion depth was advantageous in dispersing the concentrated stress in the cortical bone and did not significantly affect the micromovement associated with early osseointegration failure.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.175-186
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• 2022

A crossed occlusion resulting from the presence of posterior teeth in one arch but no opposing teeth in the opposite arch results in collapse of the vertical dimension. In this case, the patient has a class III malocclusion with crossed occlusion and anterior crossbite. In order to evaluate the proper vertical dimension, provisional denture was used to stabilize the vertical occlusal dimension for 3 months. After, provisional fixed restoration was used for the stabilizing occlusal relationship and aesthetic improvement for lip support. Definitive prosthesis in implants in the mandible and abutments in the maxillary were using Porcelain-fused-to-metal crown (PFM) crown and the maxillary unilateral edentulous area was treated with removable partial dentures. Through this, proper support of the posterior region and normal anterior occlusal relationship were formed, and the patient was able to obtain aesthetically and functionally satisfactory treatment results.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.6
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• pp.664-670
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• 2004

Statement of problem. One of the common problems of dental implant prosthesis is the loosening of the screw that connects each component, and this problem is more common in single implant-supported prostheses with external connection. Purpose. The purpose of this study was to examine the changes of detorque values of abutment screws with external connection in different abutment heights. Materials and methods. After cyclic loading on three different abutment heights, detorque values were measured. Abutments were retained with titanium abutment screws tightened to 30 Ncm (30.5 kgmm) with digital torque gauge as recommended by the manufacturer. Replacing abutments, implants and titanium abutment screws with new ones at every measurement, initial detorque values were measured six times. In measuring de torque values after cyclic loading, Avana Cemented Abutments of 4.0 mm collar, 7.0 mm height (Osstem Co., Ltd., Seoul, Korea) were used with three different lengths of 5.0, 8.0, 11.0 mm. Shorter abutments were made by milling of 11.0 mm abutment to have the same force-exercised area of 4.5 mm diameter. Sine curve force (20N-320N, 14Hz) was applied, and detorque values were measured after cyclic loading of 2 million times by loading machine. Detorque values of initial and after-loading were measured by digital torque gauge. One-way ANOVA was employed to see if there was any influence from different abutment heights. Results. The results were as follows: 1. The initial detorque value was 27.8$\pm$0.93 kgmm, and the ratio of the initial detorque value to the tightening torque was 0.91(27.8/30.5). 2. Measured detorque values after cyclic loading were declined as the height of the abutment increased, that was, 5.0 mm; 22.3$\pm$0.82 kgmm, 8.0 mm; 21.8$\pm$0.93 kgmm, and 11.0 mm; 21.3$\pm$0.94 kgmm. 3. One-way ANOVA showed no statistically significant differences among these (p>0.05). 4. Noticeable mobility at the implant-abutment interface was not observed in any case after cyclic loading at all.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.150-159
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• 2019

Nowadays, dental implant is one of the widely used treatment options for edentulous patients. Recently, a method of improving the accuracy of implant surgery using an implant surgical guide has been introduced and widely used in order to accurately place the implant in a proper position. Full-guided and half-guided implant surgery can be distinguished according to the level of surgical guide application during the implant surgery. It is true that full-guided implant surgery exhibits higher accuracy, but half- guided implant surgery is often performed in a clinical situation due to the factors such as the circumstances of the operation. A partially edentulous patient who lost teeth due to tooth fracture and periodontal disease was treated using implant and fixed prosthesis. Half-guided implant surgery was performed using an implant surgical guide during implant surgery, the accuracy of implant placement was analyzed.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.189-194
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• 2019

It is necessary to set the correct occlusal plane and to distribute the occlusal force uniformly considering the state of the opposing dentition during the prosthetic of the single edentulous patient with severe alveolar bone resorption. Implant supported overdenture is superior to complete denture in terms of maintenance and stability, and limited implants are used in fully edentulous patients with high alveolar bone resorption. Telescopic attachments using a newly introduced material based on poly-aryl-ether-ketone (PAEK) have the advantages of typical telescopic copping, excellent abrasion resistance, and are lighter and more economical than conventional implant overdentures. In this case, we restored maxillary arch with a implant retained overdenture using the telescopic attachment made of Pekktonand the mandible was restored with fixed implant prosthesis. Through these procedures esthetic aspects and functional outcomes were satisfactorily achieved.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.2
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• pp.104-112
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• 2024

When teeth are extracted, patient face social, psychological and aesthetic problems which can be minimized by fabricating a interim immediate denture. Interim immediate denture manufactured using digital technology can be completed with reduced number of patients' visits and simple laboratory process. Implant-supported removable partial denture (ISRPD) has been suggested as alternative treatment option when fixed implant prosthesis is not feasible. In this case, interim immediate dentures were fabricated using digital technology for patient after teeth extraction and treatment using ISRPD by installing implants and surveyed crowns is found to be successful with better support, stability and maintenance of removable partial dentures.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.2
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• pp.209-222
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• 2011

Missing anterior teeth can be replaced using any of a number of methods. Patients may choose to replace missing teeth with a prosthesis that is either removable, fixed, or retained with implants. For patients faced with financial, anatomical, and/or esthetic limitations, the edentulous region can be restored successfully and esthetically with a properly designed and fabricated rotational path RPD. The rotational path RPD is a partial removable dental prosthesis that incorporates a curved, arcuate, or variable path of placement allowing one or more of the rigid components of the framework to gain access to and engage an undercut area. The rigid retainer must gain access to the infrabulge portion of the tooth by rotating into place. Either a minor connector or proximal plate provides retention through its intimate contact with a proximal tooth surface. A specially designed dovetails or asymmetric rest seats provides support and embracing effects. Correctly designed and fabricated rotational path RPD can provide improved esthetics, cleanliness, and retention. But rotational path RPDs are technique sensitive since the rotational path RPD has little margin of laboratory error that rigid retainers cannot be adjusted like conventional clasps can, RPD framework must be remade once the retention is lost. The sufficient understanding of the concept for the rotational path RPD is required for clinically successful treatment. This clinical report describes in detail the theoretical, laboratory considerations and the treatment of a patient with an anterior maxillary edentulous area treated by an AP path rotational RPD that had a difficulty in long term maintenance and describes another clinical case in which more reasonable treatment procedures were approached after analyzing the former case.

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.4
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• pp.272-281
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• 2020

Agenesis of permanent tooth in adolescent patients can be treated either by orthodontic treatment for space closure or by maintaining the space until implant restoration can be carried out in adult. However, gradual atrophy of alveolar bone width makes it difficult to restore the prosthesis in the future or may cause unaesthetic results. Therefore, maintaining of not only the missing space but also the alveolar bone width should be considered. This case is a treatment whereby a temporary replacement of missing 2 mandibular incisors in adolescent patient was carried out using 2 temporary anchorage devices (TADs). Two TADs were placed horizontally 2 - 3 mm below the top of alveolar ridge, and fixed with artificial teeth by stainless steel wires extended. During the 2 year follow-up, neither gingival inflammation nor loss of the TADs have occurred. In the radiographic evaluation, the growth of the adjacent alveolar bone was not inhibited, and the width of the alveolar bone was maintained.