• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.1
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• pp.1-17
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• 2008

The purpose of this study were to report the reasons for removal of fixed prostheses and survival rate of abutment teeth. A total 192 fixed prostheses removed at Chosun university Dental Hospital and 308 abutment were investigated. The most frequent reason of removal was periodontal problem(30.7%), followed by caries(29.7%), then periapical problem(18.8%) and defective margins(14%). In metal ceramic crown, periodontal problem was the most frequent reason of removal. In complete cast crown, caries was the most frequent reason of removal. Periapical and periodontal problem was the most frequent reason people under forties and over fifties, respectively. Of the 308 abutment teeth, vital and non-vital teeth were 135(43.8%) and 173(56.2%), respectively. Of 135 vital abutment teeth, 39(28.9%) were extracted and of 173 non-vital abutment teeth, 85(49.1%) were extracted. Each risk factor for removal of fixed prostheses and extraction of abutment should be evaluated more clearly for prediction of prognosis of final prostheses and abutment teeth.

• Journal of dental hygiene science
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• v.15 no.1
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• pp.54-59
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• 2015

The present study investigated the influences of various abutment teeth shapes (maxillary right canine, pre-molar, molar) on the marginal adaptation of computer aided design/computer aided manufacturing-fabricated zirconia core. In vitro adaptation of zirconia cores manufactured by three different abutments were evaluated. Thirty zirconia cores were made per each models and the adaptation was evaluated through a silicone replica technique. The measurement of the adaptation was carried out using digital microscope. The mean and standard deviation of each reference point were analyzed using the one-way (ANOVA) and Tukey's honestly significant difference tests (${\alpha}=0.05$). The overall marginal fits of the zirconia cores were as follows: canine: $47.59{\mu}m$, pre-molar: $43.74{\mu}m$, molar: $40.36{\mu}m$. They were no statistically significant differences between groups for adaptation (p>0.05). This confirmed that the type of abutment teeth used does not determine the precision of fit of zirconia core.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.4
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• pp.490-494
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• 2019

Abutment teeth supporting removable partial denture could be faced a number of problems including development of dental caries. If the existing removable partial denture is in clinically acceptable state and the patient does not want to replace the existing removable partial denture, then a new prosthesis for abutment teeth need to be made. The procedure of fabricating a new prosthesis of abutment teeth for existing removable partial denture is complicate and technically challenging. To fabricate the abutment crown, the original cast of patient obtained before any complication to the abutment teeth is required. The original cast should also contain teeth other than the abutment teeth as a reference point. Once the cast is prepared, CAD/CAM could be used to produce retrofitting prosthesis effortlessly and efficiently. This clinical report presents fabricating a crown to fit existing removable partial denture using CAD/CAM for a patient with post and core failure and dislodged prosthesis. The prosthesis had high stability with minimum adjustment yielding satisfying result.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.3
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• pp.212-217
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• 2018

Purpose: This study was to assess clinically the incidence of abutment screw loosening of posterior implant-supported fixed prosthesis and its affecting factors. Materials and methods: 391 implant-supported crowns restored from January 2013 to January 2016 were included in this study. All restorations were fabricated with either a single crowns or a splinted crown, and cemented with temporary cement. The incidence of abutment screw loosening is investigated and gender, restoration position, opposing teeth, restoration type, abutment connection type were assessed as possible factors affecting abutment screw loosening. Results: During the observation period (2 - 5 years), abutment screw loosening was found in 29 restorations (7.4%). It took 3 to 48 months (means 19.5 months) to loose the screw, and three of these implants were fractured. Among the factors considered, there were statistically significant differences at abutment screw loosening rate between molar group (9.4%) and premolar group (2.6%) (P<.019). According to the type of opposing teeth, there were statistically significant differences between nature teeth (74.7%) and implant (25.0%), removable denture (3%) (P<.019). The other possible factors did not have a significant effect on loosening of the abutment. Conclusion: The incidence of abutment screw loosening in posterior restoration was 7.4%. Abutment screw loosening were more likely to occur in molars group than premolar group, and according to the opposing teeth, there were the greatest frequency in nature teeth than implant and removal denture. There was a statistically significant difference.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.639-645
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• 2018

The objective of this research was to compare the precision of scanning the digital abutment impression and gypsum model according to 3-dimensional superimposing different skills. There were made with the abutment impression and gypsum model of a maxillary 1st premolar, blue light scanner scanned to obtain the stereolithography (STL) file. After the same process was performed 10 more times without moving them on the scanner table about the abutment impression and gypsum model, respectively (n=11, per types). By superimposing the date of scanning the abutment impression and gypsum model used with no control and best-fit-alignment skills, 10 color-difference maps and root mean square (RMS) data were obtained. The independent t-test was performed to compare RMS data between the each other groups (${\alpha}=0.05$). In the scanning abutment impressions, $RMS{\pm}SD$ of no control, best-fit-alignment showed $6.86{\pm}0.94$, $5.04{\pm}0.24$. in the scanning gypsum model, $4.98{\pm}1.16$, $3.39{\pm}0.07$, all groups showed a significant difference (P<0.001). Trough the this study's result, not only best-fit-alignment but no control is used with digital dental computer-aided design/computer-aided manufacturing (CAD/CAM) research and clinical part.

• The Journal of the Korean dental association
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• v.32 no.6 s.301
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• pp.435-442
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• 1994

• The Journal of the Korean dental association
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• v.24 no.7 s.206
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• pp.617-632
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• 1986

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.2
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• pp.201-209
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• 2021

In removable partial dentures, many types of retentive systems have been studied and applied in clinical treatment. One of those systems is the double crown denture system which is widely used in European countries such as Germany and Sweden. Telescopic double crown dentures have several advantages such as convenience in maintaining oral hygiene, enabling to transfer occlusal force along the long axis of the abutment, and secondary splinting effect between the abutments which leads to higher clinical performance compared to conventional removal partial dentures. In this clinical case, the patient was initially restored with a maxillary hybrid telescopic double crown denture with friction pin using remaining natural teeth as abutments. After 7 years, due to lack of recall check-up and poor oral hygiene, the abutment teeth were affected by periodontitis and 4 out of 5 of the abutment teeth had to be extracted. 3 additional implants were placed and the original abutment tooth with the inner crown was maintained. The mandible had fixed prostheses including implants but nevertheless, with strategic implant placement, the patient adapted well and was satisfied with the new maxillary tooth-implant combined double crown denture.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.19-28
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• 2022

In removable partial dentures, abutment teeth are essential for support, maintenance, and stability of partial dentures, and are an important factor in the fabrication of functional dentures. If the number of periodontally sound abutments is sufficient and they are located on both sides, it will be easy to manufacture functional dentures with good support, maintenance, and stability. But on the contrary, if the number of teeth is insufficient or if they are located on one side, it is biomechanically disadvantageous and relatively difficult to make functional denture. On the other hand, recently, implant-supported removable dentures, which reinforce the three elements of maintenance, support, and stability by using implant surveyed crown, have been frequently selected as treatment plans. In particular, by adding an implant surveyed crown when only a small number of residual teeth remain, mastication efficiency, esthetics, patient comfort, and pronunciation can be improved. In this case, bilateral posterior extension partial denture was fabricated using implant surveyed crown as abutments by placing implants in the premolars area opposite to the residual tooth unilaterally in the mandible. As a result, the asymmetry of the abutment was resolved, and the maintenance and stability of the denture was achieved.

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