• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.1
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• pp.59-68
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• 2010

Recently, dental implants extensively inserted on edentulous area show highly clinical success rate. However, clinicians cannot exclude the possibility of failure and it often unexpectively occures. Many possible factors associated with failure of dental implants have been reported but controversy exists over the extent to them. In this study, we collected 212 patients who had been inserted 358 dental implants on mandibular premolar and molar area from 2005 to 2006. The survival rate of fixtures was recorded according to age of patients, implantation site, implant system, diameter and length of fixtures. Multi-variable analysis using SPSS chi-square test was operated to verify relation of each factors and survival rates. Accumulative survival rate was 98.3% for 3 years. Only diameter of fixtures was related to the implant survival rate. This may be thought that wider fixtures had been chosen to rescue implants or used in sites of poor bone quality. Further continuous study will be needed for direct guidance associated with survival rate of implants.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.330-337
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• 2018

In edentulous patients, implant - supported fixed prosthesis treatment has been proved to be useful, but involves complex treatment process. On the other hand, in the modern dentistry, digital technology has been developed day by day and it has expanded its range to the implant restoration of edentulous patients. In this case, a digital system was used for all stages of diagnosis, surgery, design and fabrication of provisional implants fixed prosthesis restoration in 66-year-old mandibular edentulous patients. In the preoperative diagnosis stage, a provisional restoration was designed based on the mucosal scan using the intraoral scanner and the stable occlusion of prefabricated complete denture of the patient. After flapless implant surgery using the surgical guide, the prefabricated interim restoration was connected to the implant and used as immediate provisional restoration. The final restoration was designed and fabricated by transferring the vertical dimension and the centric relation of the provisional restoration with stable occlusion using digital technology. We report a simple protocol of implant treatment in edentulous patients by using digital techniques to preserve the patient's vertical dimension and occlusion.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.4
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• pp.423-439
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• 2012

This case report described a technique utilizing a computer-aided design (CAD)/computer-aided machining (CAM) - guided surgical implant placement and prefabricated temporary fixed prosthesis for an immediately loaded restoration. The advantages of CAD/CAM guided implant procedures are flapless, minimally invasive surgery and shorter surgery time. With this technique, less postoperative morbidity and delivery of prosthesis for immediate function would be possible. A patient with an edentulous maxilla received 8 implants in maxilla using CAD/CAM surgical templates. Prefabricated provisional maxillary implant supported fixed prosthesis were connected immediately after implant installation. Provisional prosthesis was evaluated for aesthetics, function during 6 months. Definitive implant supported fixed porcelain fused metal bridges were fabricated.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.3
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• pp.245-256
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• 2023

When restoring with a dental digital system for implant-supported prosthesis, a double digital scanning technique is required: an intraoral scan of the three-dimensional implant location and intraoral scan after placement of temporary denture or provisional prosthesis. During the intraoral scan, the use of scan body as a stable landmark can improve the accuracy of digital impression and simplify laboratory process. In this case, a full-digital system was used to plan and fabricate a custom abutment, provisional prosthesis, and definitive prosthesis. After implant placement, the scan area of the intraoral scan body connected with implant and the intraoral scan body marked on the inside of temporary denture were superimposed. Out of the superimposed files, a custom abutment and provisional prosthesis were fabricated which match the vertical dimension of temporary denture, and definitive prosthesis was fabricated based on provisional prosthesis. We report this case because result has been functionally and esthetically satisfactory by using vertical dimension and central relation set during the fabrication of temporary denture to the definitive prosthesis.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.3
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• pp.292-299
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• 2017

Long-term alveolar bone resorption in edentulous patient causes difficulty in denture use. Applying an implant overdenture with 2 to 4 implants to edentulous patient is easily approachable. Moreover, it improves denture stability, support, and retention. Milled bar, the attachment used in implant overdenture, can be used to induce better stability and retention to the supporting structure than conventional bar. It has become convenient to use due to the development of CAD/CAM system which had allowed the simplification of dental techniques. In this case, application of conventional maxillary full denture and mandibular overdenture made of CAD/CAM milled bar with 4 implants showed satisfactory results in the patient who had used upper and lower full dentures for a long time.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.4
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• pp.391-401
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• 2009

The successful outcome of dental implants is mainly the result of intial implant stability following placement. The aim of this study was to investigate the effect of a self-tapping blades and implant design on initial stability of two tapered implant systems in poor bone quality. The two different implant systems included one with self-tapping blades and one without self-tapping blades. D4 bone model using Solid Rigid Polyurethane Form was used to simulate poor bone densities. The insertion torque during implant placement was recorded. Resonance frequency Analysis (RFA), measured as the implant stability quotient (ISQ), was assessed immediately after insertion. Finally, the implant-bone specimen was transferred to an Universal Testing Machine to measure the axial pull-out force. Insertion torque values and maximum pull-out torque value of the non self-tapping implants were significantly higher than those in the self-tapping group (P = 0.008). No statistically differences were noted between the two implant designs in RFA. Within the each implant system, no correlation among insertion torque, maximum pull-out torque and RFA value could be determined. Higher insertion torque of the non-self-tapping implants appeared to confirm higher clinical initial stability. In conclusion, implants without self-tapping blades have higher initial stability than implants with self-tapping blades in poor bone quality.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.5
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• pp.305-311
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• 2016

Induction heating is the process in which an electrically conducting object (usually a metal) is heated by electromagnetic induction through heat generated in the object by eddy currents. The main advantage of an induction heating device is the generation of the heat inside the target object itself. Hence, non-contact and safe heating devices are widely used in many industrial and medical fields. Recently, a new dental implant system was developed using a shape-memory alloy, wherein an artificial tooth could be easily removed from the dental implant by heating. This paper discusses the development of an induction-heating device to remove the dental crown in the new implant system. First, the finite element simulation of electromagnetic and thermal coupling analysis was implemented to obtain the temperature distributions of the target object for various frequencies, input currents, and coil shapes. Based on the simulation results, experiments were conducted by using prototypes, and an induction heating device was developed to remove the dental crown from the implant.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.164-173
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• 2009

Purpose: The purpose of this study was to evaluate the effect of abutment material on screw-loosening before and after cyclic loading. Among the different materials of abutments, zirconia and metal abutment were used. Material and methods: Two types of implant systems: external butt joint(US II, Osstem Implant, Korea) and internal conical joint(GS II, Osstem Implant, Korea) were used. In each type, specimens were divided into two different kinds of abutments: zirconia and metal(n=5). The implant was rigidly held in a special holding to device ensure fixation. Abutment was connected to 30 Ncm with digital torque gauge, and was retightened in 30 Ncm after 10 minutes. The initial removal torque values were measured. The same specimens were tightened in 30 Ncm again and held in the cycling loading simulator(Instron, USA) according to ISO/FPIS 1480. Cycling loading tests were performed at loads 10 to 250 N, for 1 million cycles, at 14 Hz,(by subjecting sinusoidal wave from 10 to 250 N at a frequency of 14 Hz for 1 million cycles,) and then postload removal torque values were evaluated. Results: 1. In all samples, the removal values of abutment screw were lower than tightening torque values(30 Ncm), but the phenomenon of the screw loosening was not observed. 2. In both of the implant systems, initial and postload removal torque of zirconia abutment were significantly higher than those of metal abutment(P<.05). 3. In both of the implant systems, the difference in removal torque ratio between zirconia abutment and metal abutment was not significant(P>.05). 4. In metal abutments, the removal torque ratio of GS II system(internal conical joint system) was lower than that of US II system(external butt joint system)(P<.05). 5. In zirconia abutments, the difference in removal torque ratio between the two implant systems was not significant(P>.05). Conclusion: Zirconia abutment had a good screw joint stability in the condition of one million cycling loading.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.119-126
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• 2022

Mini-implant has been reported as an alternative method to conventional diameter implants in the treatment of mandibular anterior region with narrow ridge. However, one-piece type mini-implant showed biological and technical complications, such as peri-implantitis by residual cement and prosthetic detachment. Recently, one-piece type mini-implant with additional retentive structure has been introduced to increase the retention and stability of the mini-implant. The mini-implant is based on spreading the upper retentive structure with a spreader and connected it with the inner surface of the zirconia prosthesis. In two cases, we tried to reduce these complications through the mini-implant on the narrow mandibular anterior region, and it was possible to reduce the overall treatment period through a digital system. In this case report, restoration using the digital mini-implant system showed improvement of patient satisfaction on the aspect of function and esthetic in the narrow mandibular anterior region.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.3
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• pp.243-253
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• 2009

This report described a technique utilizing a computer-aided design (CAD) /computer-aided machining (CAM) - guided surgical implant placement and prefabricated fixed complete denture for an immediately loaded restoration. A patient with an edentulous maxilla and mandible received 6 implants in maxilla and 6 implants in the mandible using CAD/CAM surgical templates. Prefabricated provisional maxillary and mandibular implant supported fixed prostheses were connected immediately after implant installation. Provisional prostheses were evaluated for aesthetics, function during 6 months. Definitive prostheses were fabricated.