• The Journal of the Korean dental association
• /
• v.22 no.11 s.186
• /
• pp.953-960
• /
• 1984

The author applied the attachment fixation overdenture on the patient whose residual alveolar ridge height was poor to increase mechanical denture retention, and observed the periodontal condition of the abutment roots after insertion of attachment fixation overdenture. The author obtained the conclusions as follows; 1. Attachment fixation overdenture showed better mechanical retention than conventional overdenture did, but it resulted unfavorable crown-root ratio. 2. Within one year after insertion, there were not significant changes in periodontal health, which was indicated by plaque index, gingival index, pocket depth, tooth mobility gingival hyperplasia and alveolar bone change. 3. Mild periodontal thickening was observed. 4. This study emphasized the importance of adequate follow-up care and home care instructions.

• The Journal of Advanced Prosthodontics
• /
• v.9 no.1
• /
• pp.14-21
• /
• 2017

PURPOSE. The aim of this study was to compare the retention of mini implant overdenture by the number, the type of magnetic attachment, and the directions of applied dislodging force. MATERIALS AND METHODS. The experimental groups were designed by the number and type of magnetic attachment. Twenty samples were tested with Magden implants. Each attachment was composed of the magnet assembly in overdenture sample and the abutment keeper in a mandibular model. Dislodging forces were applied to the overdenture samples (50.0 mm/min) in 3 directions. The loading was repeated 10 times in each direction. The values of dislodging force were analyzed statistically using SPSS at 95% level of confidence. RESULTS. The retentive force of group 2 was greater than that of group 1 in both types of attachment in every direction (P < .05). Oblique retentive force of flat type magnetic attachment was higher than that of cushion type attachment in both groups (P < .05). In group 1, oblique retentive force showed the highest and anterior-posterior retentive force showed the lowest value in both attachment types (P < .05). In group 2, both types of attachment showed the lowest retentive force with anterior-posterior direction of dislodging force (P <.05). CONCLUSION. Proper retentive properties for implant overdenture were obtained, regardless of the number and type of magnetic attachment. In both types of magnetic attachment, the greater retentive force was attained with more implants. Oblique retentive force of flat type magnetic attachment was greater than that of cushion type. Among all subgroups, anterior-posterior retentive force was the lowest among three different directions of dislodging force.

• 대한치과보철학회:학술대회논문집
• /
• 2000.04a
• /
• pp.42-42
• /
• 2000

• The Journal of Korean Academy of Prosthodontics
• /
• v.38 no.1
• /
• pp.98-107
• /
• 2000

Three linear strain gauges (KFR-02N-120-C1-23, Kyowa, Japan) were placed around the abutment of implant future and the maximum axial loads on the mandibular implants supporting over dentures were registered in experimental model when the overdenture was removed. The overdenture attachments used in this study were Round bar Hader bar, Dolder bar with and with out spacer. The retention of bar attachment was measured using universal testing machine while being con-trolled by Activating set and Deactivator except in case of the Hader bar. Simultaneously strains were recorded with the strain smart program in strain P-6000 series (Measurement group, Raleigh, USA). The maximum axial load was calculated and compared with each other. The results were as follows: 1. The amount and the timing of the maximum axial loads were different between the right and left implant in all attachment systems. 2. The retention of bar attachment except Hader bar could be adjusted but the controllability was different among the attachment systems. 3. The more the axial load, the higher the retention with Hader bar and Dolder bar without spacer. but the tendency of increase was not shown with round bar and Dolder bar with spacer.

• The Journal of Korean Academy of Prosthodontics
• /
• v.35 no.3
• /
• pp.577-608
• /
• 1997

The purpose of this study is to evaluate the stress distribution in the bone around dental implants supporting mandibular overdenture according to the number of implant and the type of attachment. Two or four implants were placed in an edentulous mandibular model and three dimensional photoelastic stress analysis was carried out to measure the fringe order around the implant supporting structure and also to calculate principal stress components at cervical area of each implant. The attachments tested were rigid and resilient type of Dolder bar, Round bar, Hader bar and Dal-Ro attchment. The results were as follows ; 1. In 2-implant supported overdenture using Round bar, Hader bar, and Dal-Ro attachment, compressive stress pattern was observed on the supporting structure of implant on loaded side, while tensile stress pattern in unloaded side. 2. In 2-implant supported overdenture using Dolder bar, the rigid Dolder bar shared the occlusal loads between 2 implants in a more favorable manner than was exhibited by the resilient type, while the resilient type placed a more stress on the distocervical area of the implant on the loaded side. But compressive stress pattern was observed in both the loaded and unloaded sides in either case. 3. In 2-implant supported overdenture, rigid and resilient type of Dolder bar exhibited more cross arch involvement than the Round bar, Hader bar, or Dal-Ro attachment. 4. In 4-implant supported overdenture using resilient Dolder bar and Hader bar, stress turned out to be distributed evenly among the implants between loaded and unloaded side, but thor was no reduction in the magnitude of the stress in the surrounding structure of implant contratry to 2-implant supported overdenture. 5. The stress pattern at cervical area of implant was different with the number of implant or the type of attachment but the overload, harmful to surrounding structure of implant, was not observed.

• The Journal of Advanced Prosthodontics
• /
• v.5 no.3
• /
• pp.333-340
• /
• 2013

PURPOSE. This study was accomplished to assess the biomechanical state of different retaining methods of bar implant-overdenture. MATERIALS AND METHODS. Two 3D finite element models were designed. The first model included implant overdenture retained by Hader-clip attachment, while the second model included two extracoronal resilient attachment (ERA) studs added distally to Hader splint bar. A non-linear frictional contact type was assumed between overdentures and mucosa to represent sliding and rotational movements among different attachment components. A 200 N was applied at the molar region unilaterally and perpendicular to the occlusal plane. Additionally, the mandible was restrained at their ramus ends. The maximum equivalent stress and strain (von Mises) were recorded and analyzed at the bone-implant interface level. RESULTS. The values of von Mises stress and strain of the first model at bone-implant interface were higher than their counterparts of the second model. Stress concentration and high value of strain were recognized surrounding implant of the unloaded side in both models. CONCLUSION. There were different patterns of stress-strain distribution at bone-implant interface between the studied attachment designs. Hader bar-clip attachment showed better biomechanical behavior than adding ERA studs distal to hader bar.

• The Journal of Korean Academy of Prosthodontics
• /
• v.37 no.1
• /
• pp.93-103
• /
• 1999

Stress distribution on mandibular implants supporting overdentures were registered in vitro experimental model by means of 4 rosette gauges which were placed around the implant. The overdenture attachments used in this study were the Resilient Dolder bar, Rigid Bolder bar, Round bar, Hader bar & Dal-Ro attachment. An occlusal jig was placed on the overdenture and the loading sites were 3 points which mimicked working, balancing, and median relations. With 5 and 10kg loading, strains were measured by strain indicator(P-3500, Measurement group, Raleigh, USA), and using these data, maximum and minimum principal stresses and Von Mises stress were calculated and evaluated. The results were as follows : There was a tendency of high stress concentration in the lingual side of the implant, and in the buccal side low stress was developed regardless of the attachment systems. The resilient Bolder bar concentrated highest stress among the attachment systems, and the Round bar and the Dal-Ro attachment provided comparatively low stresses around the implant. The rigid Bolder bar concentrated high stress in the mesial side, and the Dal-Ro attachment developed tensile stress patterns in the lingual and distal sides of the implant at the balancing relation.

• The Journal of Korean Academy of Prosthodontics
• /
• v.58 no.4
• /
• pp.335-341
• /
• 2020

Severe mandibular bone resorption may cause difficulties in using a complete denture. An implant overdenture is a feasible and economical treatment option as it can improve retention, stability, and support. A Locator attachment has used successfully. Recently, the next generation of the Locator attachment launched. The purpose of this article is to describe the fabrication of an implant overdenture with a Locator R-Tx attachment as well as its features.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.28 no.4
• /
• pp.397-406
• /
• 2012

Loss of tooth results in remodeling and resorption of surrounding alveolar bone which causes atrophic edentulous ridge and gradually decreasing gingival attachment. As a result, edentulous patients face difficulty in using dentures due to pain, decrease of support, decline of masticatory efficiency of complete denture. To improve this, overdenture with implant in the mandible and attachment are considered as a treatment of choice as a favorable treatment. In this case, a patient with edentulous ridge for long period is rehabilitated by complete denture in maxilla and implant overdenture using Locator$^{(R)}$ attachment in mandible.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.31 no.4
• /
• pp.378-386
• /
• 2015

Overdenture has the advantage of improving the stability and retention of the denture but the abutment may be easily affected by caries or periodontal disease and the thin denture can be easily broken. The magnetic attachment overdenture has a high vertical retention but a low horizontal retention, thus, exerting a less disruptive force to the abutment or implant and shows less abrasion or damage compared to other mechanical retainers. Denture fractures in overdenture is caused by the thin denture base as the attachment is inserted, but it may also be caused by the difference in detrusion between soft tissue and hard tissue, and between an implant and a natural tooth. To compensate this shortcoming, a magnetic attachment with a silicone ball inserted in the magnet was developed as we report a successful case using this specific type of magnetic attachment overdenture.