• The Journal of Korean Academy of Prosthodontics
• /
• v.37 no.2
• /
• pp.185-199
• /
• 1999

This study was peformed to investigate the distribution and magnitude of stress at supporting tissue of abutment teeth and residual ridge tissue with remaining unilateral posterior teeth. Four types of removable partial dentures that included clasp retained removable partial denture, attachment retained removable partial denture, telescopic removable partial denture, and swing-lock partial denture were designed, and strain gauge was used for stress analysis. Each prosthesis was subjected to simulated vertical and oblique load. The following conclusions were drawn from this study. 1. The clasp retained removable partial denture generally distributed simulated vertical force more evenly to the supporting structure. 2. The stress at buccal side of 1st premolar was the lowest in swing-lock partial denture and that was highest in attchment retained removable partial denture. The stress at lingual side of 1st premolar was the lowest in telescopic partial denture. 3. In clasp retained removable partial denture, stress was lower at load site and ridge crest at mid-line, but it was higher at 1st premolar area on vertical load. 4. In attachment removable partial denture, stresses at buccal side of 1st premolar. lingual side of 1st premolar on vertical load, and ridge crest at midline on oblique load were higher. 5. In telescopic removable partial denture, stress at lingual side of 1st premolar was the least in all removable partial dentures, but the stress at load site was higher. 6. In swing-lock removable partial denture, stress at buccal side of 1st premolar was the lowest, and stresses at load site and distal end of residual ridge crest were higher.

• The Journal of Korean Academy of Prosthodontics
• /
• v.57 no.1
• /
• pp.42-48
• /
• 2019

In the case of a patient with a small number of unilateral remaining teeth in the mandible, a restoration with conventional removable partial denture cannot provide sufficient retention and resistance. A harmful stress from the poor stability of denture on remaining teeth occurs due to alveolar bone resorption in edentulous area. Although implant fixed prosthesis can provide multiple benefits over conventional removable partial denture, there are limitations come from anatomic structures and costs. In this case, an implant-assisted removable partial denture (IARPD) with a couple of implants placed in strategic positions can be a treatment modality. The objective of this article is to present a case report of two patients showed satisfactory clinical outcomes during three-year follow-up period describing the fabrication and advantages of removable partial denture assisted by teeth and implants (IARPD) for a patient with a small number of unilateral remaining teeth in mandible using Locator as an implant attachment.

• The Journal of Korean Academy of Prosthodontics
• /
• v.57 no.2
• /
• pp.176-181
• /
• 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 Korean Academy of Prosthodontics
• /
• v.30 no.2
• /
• pp.203-224
• /
• 1992

The purpose of this study was to evaluate the stress distribution developed in supporting structures by distal extension removable partial denture with 4-types of direct retainer. The direct retainers examined were Akers clasp, RPI clasp, RPA clasp and RPL clasp in bilateral & unilateral free end case. 3-dimensional photoelastic stress analysis was used to record the isochromatic fringe patterns and to calculate the compressive stress at measuring points. The results were as follows. 1. In bilateral free end case, RPI clasp exhibited the similar stress distribution on distal and mesial alveolar crest but Akers clasp exhibited higher stress concentration on distal alveolar crest than mesial alveolar crest. 2. In bilateral free end case, RPA clasp and RPL clasp exhibited the similar stress distribution on distal and mesial alveolar crest and RPL clasp exhibited higher stress concentration on buccal alveolar crest than lingual alveolar crest. 3. Akers clasp produced high stress concentration on residual alveolar ridge distally, but RPI clasp, RPA clasp and RPL clasp produced even stress distribution on residual alveolar ridge. 4. Removable partial denture in unilateral free end case exerted higher stress on abutment tooth root apex than bilateral distal extension removable partial denture.

• The Journal of Korean Academy of Prosthodontics
• /
• v.52 no.2
• /
• pp.128-135
• /
• 2014

Treatment options for partially edentulous patients are fixed partial denture, removable partial denture and implant supported fixed partial denture. In case of a patient with a few remaining teeth, removable partial denture and implant supported fixed prosthesis are available. For implant fixed prothesis, enough implant fixtures are required and the patient's general condition, local factors and economic status must be considered. When the condition of the abutments and the residual ridge is favorable and the prosthesis is well designed, removable partial denture can be an option. In removable partial denture, the bilateral support is important. If the teeth remain unilateral, harmful stress is put on the abutments by the fulcrum line. In this situation, strategic implantation and implant-retained or assisted removable partial denture is beneficial to the retention and support of the denture. And this can be cost-effective, functional and esthetic choice of treatment. This article describes the prosthodontic rehabilitation of Maxillary Kennedy class I partially edentulous patients. In these two cases, the patients had a small number of teeth and they were restored by the combination of a removable partial denture and dental implants.

• Journal of Korean Dental Science
• /
• v.15 no.1
• /
• pp.75-83
• /
• 2022

Crown-type implant-assisted removable partial dentures (CIRPDs) can be a feasible treatment option for partially edentulous patients. Here we report a case with remaining unilateral mandibular teeth. Two implants were placed in the posterior portion of the mandible using a surgical guide, and a distal-extension removable partial denture with implant-supported surveyed crowns was fabricated. After 12 months, both the abutment teeth and implants were in good condition. The treatment outcomes were satisfactory in terms of masticatory function and esthetics. The advantages of CIRPDs and considerations for obtaining successful clinical outcomes with these dentures are also discussed.

• The Journal of Korean Academy of Prosthodontics
• /
• v.30 no.1
• /
• pp.25-42
• /
• 1992

The purpose of this study was to analyze the magnitude and distribution of stress using a photoelastic model from a unilateral distal extention removable partial dentures with five kinds of the direct retainers, that is, the bilaterally designed bar clasp of the cross-arch lingual bar and the unilaterally designed bar clasp, circumferential clasp, mini-Dalbo attachment, and telescope retainer. A photoelastic model for mandible was made of the epoxy resin(PL-1) and hardner (PLH-1) with the acrylic resin teeth used and was coated with plastic cement-1 at the lingual surface of the model, and then five kinds of removable partial dentures were set, A unilateral vertical load of about 16Kg was applied on the first molar and the stress pattern of the photoelastic model under each condition was analyzed by the reflective circular polariscope. The following results were obtained: 1. The conventional removable partial denture with the bilaterally cross arch lingual bar produced the most favorable stress distribution on the residual ridge and supporting structure of abutment teeth than the unilaterally designed removable partial dentures. 2. The unilaterally designed removable partial denture with the bar clasp produced the stress distribution on the residual ridge, except sligtly higher stress concentration on the supporting structure of the abutment teeth, similar to the conventional removable partial denture with the bilaterally designed cross arch lingual bar. 3. On the unilaterally designed removable partial dentures, the bar clasp produced greater stress distribution on the residual ridge and supporting structure of the abutment teeth than the circumferential clasp. 4. On the unilaterally designed removable partial dentures, the mimi-Dalbo attachment produced relatively higher stress concentration on the residual ridge, but produced lesser stress concentration on the supporting structure of the abutment teeth than the other direct retainers. 5. On the unilaterally designed removable partial dentures, the telescope retainer produced uniform stress distribution on the residual ridge, but produced higher stress concentration at the root apex of the terminal abutment tooth than the other direct retainers. 6. On the unilaterally designed removable partial dentures the circumferential clasp and telescope retainer produced slightly higher stress concentration on the residual ridge and supporting structure of the abutment teeth than the bar clasp and mini- Dalbo attachment.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.38 no.2
• /
• pp.110-119
• /
• 2022

When restoration for partially edentulous patients, abutments are not always in favorable positions for making removable partial dentures. Because of these situations, patients are sometimes unsatisfied with the stability and support of their removable partial prostheses. In this regard, removable partial denture using a few implant surveyed crown prostheses can be a good alternative. It can be expected to increase stability and support of removable partial dentures by strategically placing a small number of implants and restoring with implant-supported surveyed crowns. In these cases, the patients who had unilateral residual teeth on mandible were treated with two implant surveyed crowns in the tactical place to have bilateral distribution. After definitive removable partial prosthesis, the patients showed satisfaction with the masticatory function and comfort of using removable dentures.

• The Journal of Korean Academy of Prosthodontics
• /
• v.45 no.6
• /
• pp.753-759
• /
• 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
• /
• v.47 no.2
• /
• pp.206-214
• /
• 2009

Statement of problem: There are common clinical cases in which the mandibular first and second molars are missing unilaterally. Purpose: This study was designed to compare and evaluate the magnitude and distribution of stress produced by four kinds of mandibular unilateral free-end removable partial dentures that could be applied clinically in Kennedy class II cases. Material and methods: Four unilateral free-end removable partial dentures using clasp, Konus crown, resilient attachment, and flexible resin were fabricated on the photoelastic models of the Kennedy class II cases. The vertical load of 6㎏ was applied on the central fossa of the first molar of every removable partial denture in the stress freezing furnace and the photoelastic models were frozen according to the stress freezing cycle. After these models were sliced mesio-distally to a thickness of 6mm, the photoelastic isochromatic white and black lines of the sliced specimens were examined with the transparent photoelastic experiment device and photographs were taken with a digital camera. The fringe order numbers at eight measuring points in the photograph were measured with the naked eye. Results: The maximum fringe order number of each sliced specimen and the fringe order number at the residual ridge just below the loading point were in the decreasing order of the unilateral removable partial dentures using flexible resin followed by clasp, resilient attachment, and Konus crown. The fringe order number at the root apex of the second premolar was in the decreasing order of the unilateral removable partial dentures using clasp followed by flexible resin, Konus crown, and resilient attachment. Conclusion: The removable partial denture using Konus crown showed the most equalized stress distribution to the supporting alveolar bone of abutment teeth and residual ridge under the vertical loads. The removable partial denture using flexible resin can be applied to the case that has a better state of residual ridge than abutment teeth.