• The Journal of Korean Academy of Prosthodontics
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• v.28 no.2
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• pp.199-215
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• 1990

This study was to analyze the stress distribution of implant and supporting tissue in $Br{\aa}nemark$ osseointegration implant. The analysis has been conducted by using the axisymmetric finite element method and type of model according to crown material. Tests have been performed at 1 kg load on central fossa of crown portion. Each type of model was designed differently according to crown material. 1) Porcelain fused to metal crown(Model A) 2) Composite resin veneered crown(Model B) 3) Acrylic resin veneered crown(Model C) 4) Type III gold crown(Model D) The displacements and stresses of implant and supporting structures were analyzed to investigate the influence of the type of crown material. The results were obtained as follows : 1. Displacement of implant was shown uniformly downward displacement in all models and abutments were observed distally downward displacement. 2. In supporting tissues, stress was concentrated on the crest of compact bone and the spongy bone below implant. 3. The PFM and the type III gold crown showed the largest concentration of stress at the crest of compact bone and the spongy bone below implant, respectively. Acrylic resin artificial teeth and composite resin veneered crown indicated almost the same distribution of stress. 4. The gold screw, the abutment screw and the top of abutment showed the concentration of stress in implants of every model.

• Journal of Technologic Dentistry
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• v.37 no.1
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• pp.1-7
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• 2015

Purpose: The aim of this study was to evaluate the marginal and internal gap of wax copings fabricated from extraoral scanning with intraoral scanning. Methods: Fifteen study models(abutment of teeth 16) were made by PMMA. STL files of thirty abutment were prepared by intraoral scanning with extraoral scanning. Wax copings of thirty fabricated using CAD/CAM system. Marginal and internal gap of wax copings of thirty were measured by silicone replica technique and digital microscope(${\times}140$). Date were analyzed by using independent samples t-test. Results: Mean (SD) of two group were measured $55.61(27.42){\mu}m$ for totally gap of ES group and $60.67(33.14){\mu}m$ for totally gap of IS group. But marginal and internal gap of two group were not differences statistically significant(p>0.05). Conclusion: Evaluation of marginal and internal gap of two group showed that no differences statistically significant and clinically acceptable results.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.2
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• pp.197-206
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• 2006

Statement of problem: One of common problems associated with single teeth dental implant prosthetic is the loosening of screws that retain the implants. Purpose: The maintenance of screw joint stability is considered a function of the preload achieved in the screw when the suggested initial tightening torque is applied. The purpose of this study was to investigate acquired preload after initial clamping torque for estimating screw joint stability. Material and methods: A comparative study on the effect of initial clamping of two types of implant systems with different connections was conducted Three dimensional non-linear finite element analysis is adopted to compare the characteristics of screw preloads and stress distributions between two different types of implant systems composed with abutment, screw, and fixture under the same loading and boundary conditions. Results: 1. When the initial clamping torque of 32Ncm was applied to the implant systems, all types of implants generated the maximum effective stress at the first helix region of screw. 2. Morse taper connection types of implants generate lower stress distributions compared to those by butt joint connection types or implants due to large contact surface between abutment and fixture. 3. The internal types of implant systems with friction grip type implant systems have higher resistance to screw loosening than that of the external types of implant systems since the internal types of implant systems generated larger preload than that generated by the external types for the same tightening moments.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.176-181
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• 2019

Traditional removable partial denture is a successful treatment for partial edentulous patients. When the abutment is formed with unilateral minority teeth, satisfaction with the use of removable partial denture may be lowered due to patient's discomfort and damage of the abutment. Recently, it has been reported that the unilateral posterior extension partial denture is used as a bilateral posterior extension partial denture using implant fixed prostheses as abutments. In this case, by using implant surveyed crown prostheses, bilateral posterior extension partial denture is fabricated in site that is predicted to have a poor prognosis. This resulted in improved support, maintenance, and stabilization of the removable partial denture, which were economically beneficial to patient and satisfied with use.

• The Journal of Advanced Prosthodontics
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• v.11 no.5
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• pp.262-270
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• 2019

PURPOSE. The purpose of this in vitro study was to evaluate the marginal misfits of three-unit frameworks fabricated with conventional and digital impressions techniques. MATERIALS AND METHODS. Thirty brass canine and second premolar abutment preparations were fabricated by using a computer numerical control machine and were randomly divided into 3 groups (n=10) as follows: conventional impression group (Group Ci), Cerec Omnicam (Group Cdi), and 3shape TRIOS-3 (Group Tdi) digital impression groups. The laser-sintered metal frameworks were designed and fabricated with conventional and digital impressions. The marginal adaptation was assessed with a stereomicroscope at ${\times}30$ magnification. The data were analyzed with 1-way analysis of variances (ANOVAs) and the independent simple t tests. RESULTS. A statistically significant difference was found between the frameworks fabricated by conventional methods and those fabricated by digital impression methods. Multiple comparison results revealed that the frameworks in Group Ci (average, $98.8{\pm}16.43{\mu}m$; canine, $93.59{\pm}16.82{\mu}m$; premolar, $104.10{\pm}15.02{\mu}m$) had larger marginal misfit values than those in Group Cdi (average, $63.78{\pm}14.05{\mu}m$; canine, $62.73{\pm}13.71{\mu}m$; premolar, $64.84{\pm}15.06{\mu}m$) and Group Tdi (average, $65.14{\pm}18.05{\mu}m$; canine, $70.64{\pm}19.02{\mu}m$; premolar, $59.64{\pm}16.10{\mu}m$) (P=.000 for average; P=.001 for canine; P<.001 for premolar). No statistical difference was found between the marginal misfits of canine and premolar abutment teeth within the same groups (P>.05). CONCLUSION. The three-unit frameworks fabricated with digital impression techniques showed better marginal fit compared to conventional impression techniques. All marginal misfit values were clinically acceptable.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.4
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• pp.515-522
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• 2021

Successful cases of the implant-assisted removable partial denture and implant overdentures are reported in which a few implants are additionally placed to secure the maintenance, support, and stability of the denture when there are a few residual teeth. When the lateral force applied to the tooth abutment and implant surveyed crown is minimized, the horizontal and rotational movement of the denture is significantly reduced which is an effective method that can improve the address in patients who complain of reduced retention and stability of their dentures. In this case, a small number of implants were placed to fabricate an implant-assisted removable partial denture with implant surveyed crown in the maxilla and implant overdenture with Locator^® attachment in the mandible to improve the retention, stability, and support of the dentures. The patient was satisfied with both functional and aesthetic aspects after the final dentures were delivered.

• The Journal of the Korean dental association
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• v.49 no.2
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• pp.77-84
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• 2011

The benefits of implant supported overdenture are readily apparent for the fully edentulous patients and have been well documented, however, there is deficiency of the studies regarding the combination of implants with removable partial dentures for partially edentulous patients. The purpose of this article is to review the literature concerning implants with removable partial dentures and evaluate the evidence for this clinical approach. Through many clinical case reports and studies we have searched from a broad variety of journals, we present the six considerations needed to contemplate respecting implants with removable partial denture in partially edentulous patients. First, the connection between abutment tooth and removable partial denture has to be rigid and the link between implant and removable partial denture should be hinged. Second, a mesial rest acts better in the point of force distribution for distal extension removable partial denture and splinting between implants is also a favorable choice. Third, T bar has an advantage for implants which are used as abutments in distal extension removable partial denture. Forth, as we all known functional impression is better way to reproduce movement for distal extension removable partial denture. Fifth, indirect retainer and guiding plane on the proximal surfaces of terminal abutment teeth are important in preventing denture base lifting. Sixth, implants in conjunction with removable partial denture is superior in the esthetic and phonetic as well as cost-effective point of view. We also suggest that which place we should install implants for force distribution and which diameter and length of implants should be used. in this review article, we recommend to locate the implant near of the abutment tooth for esthetics or near of first molar position for good stress distribution. The diameter and length of implant also influence to stress distribution. When we compare to conservative partial denture, patients go for removable partial denture using implants due to convenience, better support and retention according to several studies. But it is true that we need to study more on this subject and collect long term follow up cases before we discuss on it. So it is enough to bring this subject into the surface of prosthetic treatment by this article.

• The KIPS Transactions:PartA
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• v.12A no.6 s.96
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• pp.515-522
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• 2005

This paper presents a method for effectively modeling inlay/onlay prostheses restoring a tooth that are partially destroyed. An inlay/onlay is composed of internal surface adhering to an abutment, and external surface revealed to the outside sight. Internal surfaces are modeled using Minkowski sum expanding the grinded surface parts of abutments so that the internal surfaces can adhere to the abutments with closer contact. In modeling external surfaces, we exploit 3D mesh deformation techniques: DMFFD(direct manipulation free-form deformation)[19] and MWD(multiple wires deformation)[17] with three kinds of informations: standard teeth models, mesh data obtained by scanning a plaster cast of a patient's tooth, FGP(functionally guided plane) measuring the occlusion of the patients's teeth. The standard teeth models are used for building up the basic shapes of external surfaces, while the plaster fast and FGP data are used for reflecting the unique properties of adjacent md occlusal surfaces of the patients's teeth, which are slightly different to each other but very important for correct functioning. With these informations as input data, the adjacent and occlusal surfaces are automatically generated as mesh data using the techniques of DMFFD and m, respectively. Our method was implemented so that inlay/onlay prostheses fan be designed more accurately by visualizing the generated mesh models with requirements by dentists.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.3
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• pp.215-223
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• 2024

The patient in this case presented with a desire to have new dentures due to discomfort with existing ones. At the initial visit, all of teeth were missing except for the mandibular left second molar. As the patient was 65 years old, treatment with dentures and implant-supported prostheses was possible under the national health insurance system, and the patient opted for the mandibular denture using implant. Temporary prostheses were initially provided for patient adaptation, and following successful adaptation period, the treatment progressed. A maxillary complete denture and a mandibular implant-supported denture using two implants in the canines were fabricated. The mandibular denture is a Kennedy Class II removable partial denture which consists of a six-unit porcelain fused to metal fixed dental prostheses supported by the implant in the canines on both sides and left second molar serving as the abutments. Despite severe bone resorption and insufficient abutment teeth, the patient expressed satisfaction with the treatment results. In cases with economic and anatomical constraints affecting the feasibility of complete denture, implant-supported overdenture, and implant-supported fixed dental prostheses, an implant-assisted removable partial denture using implant surveyed crowns proves to be a viable and effective alternative treatment option. Nevertheless, the current dearth of scientifically rigorous studies underscores the necessity for meticulous regular check-up and occlusal assessment.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.3
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• pp.224-233
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• 2024

The patient was a 69-year-old male who had decreased VDO and overbite of the anterior teeth due to severe teeth wear. Complete mouth rehabilitation was planned to restore esthetics and function. Due to the presence of a subgingival finish line, poor fit of the margin of the temporary crown, and insufficient oral hygiene management, gingival overgrowth and bleeding occurred in many teeth, and inaccurate impressions were taken. After dividing each arch and taking partial impressions, a transfer coping was made using pattern resin on each working model die, and after being placed on the abutment teeth, a master cast was made through pick-up impression taking to produce prosthesis. In this case, the final prosthesis produced on the second master cast were fitted in terms of proximal contact, marginal fit, vertical occlusal dimension, facial appearance, esthetics, and occlusion. After complete mouth rehabilitation, the patient was satisfied with function and esthetic appearance.