• The Journal of Korean Academy of Prosthodontics
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• v.28 no.1
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• pp.43-61
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• 1990

The laser reflexion method is a new technique which permits precise contactless measurement and observation of tooth mobility as well as tooth movement. The purposes of this study were to clarify the reliability of the laser reflexion method in clinical application and to measure the abutment tooth movement according to clasp design. This study was designed to determine 1) How much a bending movement of the impression plate stand affects the position of the reflexion pattern and how precise the patient bites into plate 2) Which clasp design causes greater movement of the abutment tooth. Under medium and maximum bite forces, tests were performed on central loading position which was 13mm distal to terminal abutment tooth of distal extension removable partial denture. The movement in the mesiodistal and buccolingual directions was measured. The Duncan's New Multiple-Range test was used to compare the means for the four castings under each direction-load combination; and the paired sample t-test was for medium and maximum bite forces. From this experiment, the following results were obtained. 1. The Roach clasp, the combination clasp, the RPI clasp, and the Akers clasp did not significantly differ in their effects on buccolingual movement of the abutment tooth. 2. The direction of abutment tooth movement was not significantly altered by clasp design and all abutment tooth movements were oriented distobuccally. 3. Under medium bite force, the Akers clasp caused greater distal movement of the abutment tooth than did the combination clasp and the RPI clasp. Under maximum bite force, the Akers clasp caused greater distal movement of the abutment tooth than did the RPI clasp. 4. The testing apparatus and procedures used in this study(laser reflexion method) proved to be reliable in clinical application.

• Journal of Korean Dental Science
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• v.10 no.2
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• pp.87-95
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• 2017

This case study was to report the possible increase in the denture retention and psychological relief using the implant-supported fixed prostheses in a completely edentulous patient. The implants were placed in the anterior portion of the mandible in a patient who had completely edentulous state following the extraction of residual abutment teeth, and consequently a distal extension removable partial denture was fabricated. The patient's adaptation and satisfaction to the new prosthesis was monitored and confirmed in terms of masticatory function and esthetics, by restoring the oral condition similar to initial status before the residual teeth extraction. After 6 months, radiographic examination confirmed that both the abutment teeth and the implants were stable and well maintained. Considering the relatively short clinical follow-up period, however, continuous long-term monitoring was required.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.6
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• pp.753-759
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• 2007

Statement of problem. In distal extension removable partial denture, the preservation of health of abutment teeth is very important, but abutment teeth are subjected to unfavorable stress under unilateral loading specially. Purpose. The purpose of this study was to investigate the biomechanical effects of mandibular removable partial dentures with various prosthetic designs under unilateral loading, using strain gauge analysis. Material and methods. Artificial teeth of both canines were anchored bilaterally in a mandibular edentulous model made of resin. Bilateral distal extension removable partial dentures with splinted and unsplinted abutments were fabricated. Group 1: Clasp-retained mandibular removable partial denture with unsplinted abutments Group 2: Clasp-retained mandibular removable partial denture with splinted abutments by 6-unit bridge. Group 3: Bar-retained mandibular removable partial denture Strain gauges were bonded on the labial plate of the mandibular resin model, approximately 2 mm dose to the abutments. Two unilateral vertical experimental loadings (30N and 100N) were applied subsequently via miniature load cell that were placed at mandibular left first molar region. Strain measurements were performed and simultaneously monitored from a computer connected to data acquisition system. For within-group evaluations, t-test was used to compare the strain values and for between-group comparisons, a one-way analysis of variance (ANOVA) was used and Tukey test was used as post hoc comparisons. Results. The strain values of group 1 and 2 were tensile under loadings. In contrast, strain values of group 3 were compressive in nature. Strain values increased as the applied load in increased from 30N to 100N (p<.05) except for right side in group 1. Under 30N loading, in left side, group 1 showed higher strain values than groups 2 and 3 in absolute quantity (p<.05). And group 2 showed higher strain values than group 1 (p<.05). In right side, group 1 and 2 showed higher strain values than group 3 in absolute quantity (p<.05). Under 100N loading in left side, group 1 showed higher strain values than groups 2 and 3 in absolute quantity (p<.05). And group 2 showed higher strain values than group 1 (p<.05). In right side, group 1 and 2 showed higher strain values than group 3 in absolute quantity (p<.05). Under 30N loading, group 2 and 3 showed higher strain values in right side than in left side. Under 100N loading, right side strain values were higher than left side ones for all groups. Conclusion. Splinting of two isolated abutments by bridge reduced the peri-abutment strain in comparison with unsplinted abutments under unilateral loading. Bar-retained removable partial denture showed the lowest strain of three groups, and compressive nature.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.5
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• pp.547-555
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• 2001

This study was performed tn investigate the effects of impression method and design of the retainer on the stress of abutment tooth in distal extension RPD. Three different types of direct retainer such as Akers clasp, RPI clasp, and wrought wire clasp were designed. Stress on the abutment tooth was measured and analyzed with strain gauge method. Impressions were anatomic impression technique and functional impression technique. The following conclusions were drawn from this study. 1. The stress at the abutment tooth on all RPD was decreased in functional impression except RPI clasp retained RPD. 2 The stress at the abutment tooth on RPI clasp retained RPD was the most smallest in anatomic Impression. 3. While load is increase the stress at the abutment tooth was increased, but the change of stress at the buccal side of abutment tooth was not too much in functional impression.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.4
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• pp.442-452
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• 2022

Implant-assisted removable partial denture (IAPRD) can be considered as a simple and cost-effective treatment approach for an edentulous patient with anatomical or financial limitations. Recently, it was reported that the application of IARPD with implant supported fixed prostheses covered by the National Health Insurance Service (NHIS) were increasing. This case report describes the treatment of maxillary fully edentulous patient with anterior four-implant-supported fixed prosthesis and distal extension IARPD. This treatment approach may be advantageous over maxillary implant overdentures in some circumstances. The patient was satisfied with improved function and esthetics in the anterior area and financial benefit from the NHIS. Further long-term clinical studies are needed to establish clinical validity of the treatment approach described in this case report.

• The Journal of Advanced Prosthodontics
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• v.13 no.2
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• pp.79-88
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• 2021

Purpose. To assess peri-implant stress distribution using finite element analysis in implant supported fixed partial denture with occlusal schemes of cuspally loaded occlusion and implant protected occlusion. Materials and methods. A 3-D finite element model of mandible with D2 bone with partially edentulism with unilateral distal extension was made. Two Ti alloy identical implants with 4.2 mm diameter and 10 mm length were placed in the mandibular second premolar and the mandibular second molar region and prosthesis was given with the mandibular first molar pontic. Vertical load of 100 N and and oblique load of 70 N was applied on occlusal surface of prosthesis. Group 1 was cuspally loaded occlusion with total 8 contact points and Group 2 was implant protected occlusion with 3 contact points. Results. In Group 1 for vertical load, maximum stress was generated over implant having 14.3552 Mpa. While for oblique load, overall stress generated was 28.0732 Mpa. In Group 2 for vertical load, maximum stress was generated over crown and overall stress was 16.7682 Mpa. But for oblique load, crown stress and overall stress was maximum 22.7561 Mpa. When Group 1 is compared to Group 2, harmful oblique load caused maximum overall stress 28.0732 Mpa in Group 1. Conclusion. In Group 1, vertical load generated high implant stress, and oblique load generated high overall stresses, cortical stresses and crown stresses compared to vertical load. In Group 2, oblique load generated more overall stresses, cortical stresses, and crown stresses compared to vertical load. Implant protected occlusion generated lesser harmful oblique implant, crown, bone and overall stresses compared to cuspally loaded occlusion.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.177-194
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• 1991

The purpose of this study was to analyze the magnitude and distribution of stress using a photoelastic model from a distal extension removable partial dentures with three kinds of mandibular major connectors, that is, lingual bar, linguoplate, and swing-lock attachment. A photoelastic model was made of the epoxy resin(PC-1) and hardener(PCH-1) and coated with plastic cement-1 (PC-1) at the lingual surface of the epoxy model and set with three kinds of chrome-cobalt removable partial dentures. A bilateral vertical load of 15kg to the middle portion of the metal bar crossing both the first molars of the right and the left, and a unilateral vertical load of 12.5kg to the right first molar were applied with the use of specially designed loading device and the reflective circular polariscope was used to analyze the photoelastic model under each condition. The following results were obtained : 1. When the bilateral vertical load was applied, the magnitude and distribution of the stress concentration of the edentulous area and the terminal abutment or adjacent teeth was in the order of lingual bar, linguoplate, swing-lock attachment. 2. When the unilateral vertical load was applied, the magnitude and distribution of the stress concentration of the edentulous area and the terminal abutment or adjacent teeth was in the order of lingual bar, linguoplate, swing-lock attachment. 3. When the unilateral vertical load was applied, the magnitude and distribution of the stress concentration of the termial abutment or adjacent teeth on the non-loaded side showed the least stress distribution in case of swing-lock attachment. 4. When the bilateral vertical load and the unilateral vertical load were applied the swing-lock attachment showed the mildest uniform stress distribution on the edentulous area and the alveolar bone around the abutment teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.1
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• pp.58-65
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• 2015

For the rehabilitation of fully edentulous patients, implant-supported removable partial dentures can be considered as one of the treatment options with complete dentures or implant-supported overdentures. If removable partial dentures are used in combination with a small number of implants placed in strategically important positions, it can offer additional stability, retention and support through implants and reduce a burden of surgical procedures compared with fixed implant-supported prostheses with extensive implant placement. Moreover, the economical benefit can be expected as well. The purpose of this case report is to present a treatment in which an implant-supported removable partial denture was fabricated considering residual alveolar bone status and demands after teeth loss in a patient who had been using a distal extension removable partial denture for a long period of time. In anterior area, fixed prostheses were fabricated with implant placement and in posterior area, short implants provide only support for the removable partial denture. In addition, denture base and clasp were made of thermoplastic acrylic resin. Finally, functionally and aesthetically satisfying treatment results can be achieved.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.4
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• pp.338-344
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• 2016

Implant supported removable partial denture (ISRPD) using the implants enables favorable rehabilitation by complementing biomechanical limitations of the conventional removable partial denture (RPD). However, continuous recall check is necessary for evaluation of the mechanical and biological complications to ensure good long-term prognosis of ISRPD. This clinical report describes the complication and management in patient of Kennedy class I edentulism with ISRPD using healing abutment. The wear and fracture of healing abutment occurred at 36 months after delivery. So, healing abutment was replaced by connecting $Locator^{(R)}$ abutment for altering into the implant retained partial overdenture.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.2
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• pp.179-190
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• 2012

The installation of an implant in the distal extension area to assist a partial dentrue (IARPD) was used carefully in clinical situations. The purpose of this review on the IARPD is describing the concept, clinical results and guidelines of IARPD. For the review, a literature search was performed using the PubMed. The data from the literature suggest that the placement of the implants could improve function and patient satisfaction. In addition, IARPD reduced the residual ridge resorption. Longer and wider implant should be placed. Less than $15^{\circ}$ angulation may be not harmful. To prevent the loosening of the abutment, modified abutment or resilient attachment should be used. However, the connection method between the clasp retention and IARPD should be considered for long time success. Moreover, longitudinal clinical studies are required for evaluation of IARPD.