• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.3
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• pp.147-156
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• 2021

There are various treatment options such as conventional complete denture, hybrid prosthesis and implant-supported fixed prosthesis for fully edentulous patients. In case of implant-supported fixed prosthesis, compared to removable prosthesis, it is difficult to place the implant in the correct position considering the anatomical contours of the final prosthesis. In this case, a full mouth rehabilitation with implant-supported fixed prosthesis was performed for a patient who required extraction of all remaining teeth due to dental caries and chronic periodontitis. In the implant placement stage, the implant was placed in the desired position using a surgical guide fabricated considering the anatomical contours of the final prosthesis, and the function and esthetics were evaluated through correction and re-fabrication of the fixed provisional restoration. A final restoration of porcelain fused to gold prosthesis was delivered to the patient based on the provisional restoration. To cope with complications such as loosening of screws and fracture of porcelain, a screw-retained type prosthesis was fabricated for the posterior part and a screw-cement-retained type prosthesis for the anterior part. As a result, the patient showed an improved prognosis in terms of functional and esthetics after the final prosthesis was delivered.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.1
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• pp.71-80
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• 2014

Full-mouth reconstruction of a patient using dental implants is a challenge if there is vertical and horizontal bone resorption. Therefore, it is should be cautious in making the fixed prostheses that restore the function and the esthetics of the gingiva and teeth. In full mouth rehabilitation, CAD/CAM system makes it possible to fabricate restorations with high precision, regardless of span of the restoration. Recently, Palladium-silver (Pd-Ag) alloy which is highly biocompatible and millingable has been developed to compensate for the shortcomings of the titanium or zirconia. This clinical report presents the reconstruction of a maxillary arch with a cement retained implant supported fixed prosthesis using a Pd-Ag alloy generated by CAD/CAM system on eleven osseointegrated implants. The occluding surfaces were made of Pd-Ag alloy, to decrease the risk of chipping or fracture. The prostheses were esthetically pleasing, and no clinical complications have been reported after two years.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.119-126
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• 2022

Mini-implant has been reported as an alternative method to conventional diameter implants in the treatment of mandibular anterior region with narrow ridge. However, one-piece type mini-implant showed biological and technical complications, such as peri-implantitis by residual cement and prosthetic detachment. Recently, one-piece type mini-implant with additional retentive structure has been introduced to increase the retention and stability of the mini-implant. The mini-implant is based on spreading the upper retentive structure with a spreader and connected it with the inner surface of the zirconia prosthesis. In two cases, we tried to reduce these complications through the mini-implant on the narrow mandibular anterior region, and it was possible to reduce the overall treatment period through a digital system. In this case report, restoration using the digital mini-implant system showed improvement of patient satisfaction on the aspect of function and esthetic in the narrow mandibular anterior region.

• Journal of Technologic Dentistry
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• v.45 no.4
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• pp.124-130
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• 2023

This study aims to describe the clinical experience of single and bridge crowns fabricated using a cementless screw-retained implant prosthesis system. In the case of single crown (#37), regular link (HDL) was used, and bridge crowns (#15~#24), (#26~#27), (#17~#14) (#24~#26) were fabricated by selecting regular link and short link considering the vertical height. One abutment was hex shaped to ensure that it could be mounted while preventing insertion and prosthesis rotation. The advantages of cementless implant prosthesis include shorter chair time and periodic care, strong retention with LINK abutment, safety from inflammation, bacterial infection, and complications due to peri-implant cement, and high patient satisfaction. Dentists should double-check the position of the implant fixture and dental technicians should continuously manage the fit of the link and prosthesis with digital equipment to reduce screw loosening and fractures.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.2
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• pp.125-145
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• 2001

To compare the stress distribution patterns between cement-retained and screw-retained implant supported fixed prostheses according to four different abutment types, a three dimensional finite element analysis was performed. The hypothetical three unit fixed partial denture case was modelled on the three implants(10mm length and 3.75 diameter) in mandibular bone. Four angles of implantation(vertical, 10, 15 and 20 degree inclined mesially) were created and three different directions of force (vertical, oblique, horizontal) were applied at the center of the second premolar and distal end of the first molar for each cases. Within the limits of this study, the results were as follows, 1. In vertically installed cases, the more stress was concentrated at upper components, but mesially inclined cases, the more stress was concentrated at cortical bone. 2, The more inclined mesially the more stress was observed, especially at cortical bone. 3. The cement-retained models showed lower principal stress and more even stress distribution than the screw-retained models. 4. The similar stress distribution pattern was showed in model 1 and model 2, model 3 and model 4. 5. The more stress was observed when the loads were applied at the distal end of 1st molar than the center of 2nd premolar. 6 The fixture and the model as a whole, lesser stress values were observed when vertical loads were applied as compared to horizontal and oblique loads.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.4
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• pp.403-415
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• 2009

The purpose of the study is to establish the effect of different abutment shapes and types of cements on the retention of the full veneer casted gold crowns. Metal dies that has the similar shape with the implant abutment were manufactured using a short(5mm) and long(10mm) dies with different convergence angles. Metal dies and gold crowns, which were made from the metal dies, were cemented with Temp-bond, Temp-bond mixed with petroleum jelly, ZPC and Premier implant cement. After that, these were tested for tensile force at the point of separation. The effect of convergence angle changes of different cement types on the retention was studied as well as the effects of the cement type changes with different convergence angles on the retention. In addition, study about the marginal gap of Premier implant cement used for this experiment was conducted. The results are as followed under the in-vitro experimental limits; 1. The retention of the Temp-bond mixed with petroleum jelly decreased as the convergence angle increased, and the retention was weakest among the cements. 2. The retention of ZPC decreased as convergence angle increased. When convergence angle was 5 degrees, ZPC showed stronger retention than Premier implant cement. 3. Premier implant cement had the weakest retention when the convergence angle was 5 degrees but when the convergence angle was 10 degrees, it had the strongest retention. As the angle increased more than 10 degrees, the retention decreased. 4. Premier implant cement showed bigger marginal gap when the convergence angle was 5 degrees than 10 degrees under the experimental condition.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.4
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• pp.466-475
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• 2003

Statement of problem : In cemented implant-supported porstheses, it is still controversy what kind of cement to use. However, the effect of thermocycling on retentive strength of cemented implant-supported prostheses has not been well investigated. Purpose : This study was tested to evaluate the effects of various cements and thermocycling on retentive strengths of cemented implant-supported prostheses. Material and methods : Prefabricated implant abutments, height 5mm, diameter 6mm, 3-degree taper per side, with light chamfer margins were used. Ten specimens of two-unit fred partial denture were fabricated. The luting agents used for this study were three provisional luting agents which were Temp bond, Temp bond NE, IRM and four permanent luting agents which were Panavia F, Fuji-cem, Hy-bond Zinc cement, Hy-bond Polycarboxylate cement. 24 hours after cementation. the retentive strengths were measured by the universal testing machine with a cross-head speed of 0.5mm/min. Then cementation procedures were repeated and specimens were thermocycled 1000 times at temperature of $5^{\circ}C$ and $55^{\circ}C$. After thermocycling, the retentive strengths were measured. Results : Before thermocycling, the retentive strengths were decreased with the sequence of Panavia F. Fuji-cem. Hy-bond Zinc cement. Hy-bond Polycarboxylate cement, IRM, Temp bond NE and Temp bond, and there were significant differences among each groups(p<0.05). After thermocycling, the retentive strengths were decreased with the sequence of Panavia F. Fuji-cem, Hybond Zinc cement, Hy-bond Polycarboxylate cement, IRM, Temp bond NE and Temp bond, and there were no significant differences among Panavia F, Fuji-cem and Temp bond NE, Temp bond(p>0.05). The retentive strengths before and after thermocycling showed significant differences in Hy-bond Zinc cement. IRM, Temp bond NE and Temp bond(p<0.05). Conclusion : Within the limitation of this study, thermocycling do not affect the retentive strengths of permanent luting agents but the retentive strengths of temporary cements were reduced significantly after thermocyling.

• Journal of Technologic Dentistry
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• v.30 no.1
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• pp.57-63
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• 2008

The purpose of this study was to ascertain the effect of different abutment height and different taper of abutment on retention force of cemented implant-supported prostheses. Test specimens consisted of different abutment height group(3mm, 4mm, 5mm, 6mm, 7mm) and different taper(degrees) abutment group($4^{\circ},\;5^{\circ},\;6^{\circ},\;7^{\circ},\;8^{\circ}$). The surfaces of abutments and crowns were manufactured and finished by automatic lathe(CNC). Luting cement(Tokuso Ionomer) was prepared according to the manufacturer's instruction. And the cylinders were sealed onto the abutments and loaded in compression at 5kg for 10minutes. Excess cement was removed from the abutment-cylinder junction and the specimens were stored at room temparature for 24 hours. Specimens were tested in tension using a universal testing machine. Within the limits of this study, the following conclusions were drawn: 1. The increase in abutment height result in improvement in retention strength(P<0.05). 2. The increase in taper of abutment result in decrease in retention strength(P<0.05). 3. The decrease in abutment height result in decrease in retention strength, besides has a significantly lower retention strength at 3mm abutment height. 4. The increase in taper of abutment result in decrease in retention strength, besides has a significantly lower retention strength at $7^{\circ}$ abutment.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.416-423
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• 2009

Statement of problem: The degree of light attenuation at the time of cementation of the PLV restoration depends on characteristics such as thickness, opacity and shade of the restorations, which interfere with light transmittance and, as a result, may decrease the total energy reaching the luting cement. Purpose: The purpose of this study was to compare the degree of conversion of light-cured resin cements measuring by FT-IR in regard to different thickness, light devices and curing time. Material and methods: In the control group, a clear slide glass (1.0 mm) was positioned between the light cured resin cement and light source. The specimens of ceramics were made with IPS Empress Esthetic. The ceramics were fabricated with varying thicknesses-0.5, 1.0, 1.5 mm with shade ETC1. Rely $X^{TM}$ Veneer with shade A3, light-cured resin cement, was used. Light-activation was conducted through the ceramic using a quartz tungsten halogen curing unit, a light emitting diode curing unit and a plasma arc curing unit. The degree of conversion of the light-cured resin cement was evaluated using FT-IR and OMNIC. One-way ANOVA and Tukey HSD test were used for statistical analysis ($\alpha$< .05). Results: The degree of conversion (DC) of photopolymerization using QTH and LED was higher than results of using PAC in the control group. After polymerization using QTH and LED, the DC results from the different ceramic thickness- 0.5 mm, 1.0 mm, 1.5 mm- did not show a significant difference when compared with those of control group. However, the DC for polymerization using PAC in the 1.5mm ceramic group showed significantly lower DC than those of the control group and 0.5 mm ceramic group (P<.05). At 80s and 160s, the DC of light-cured resin cement beneath 1.0 mm ceramic using LED was significantly higher than at 20s (P<.05). Conclusion: Within the limitation of this study, when adhering PLV to porcelain with a thickness between 0.5-1.5 mm, the use of PAC curing units were not considered however, light cured resin cements were effective when cured for over 40 seconds with QTH or LED curing units. Also, when curing the light cured resin cements with LED, the degree of polymerization was not proportional with the curing time. Curing exceeding a certain curing time, did not significantly affect the degree of polymerization.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.201-208
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• 2008

Statement of problem: A new implant impression technique which use abutments as impression coping, and use resin cement as a splinting material was described. Accuracy of this technique was compared with conventional closed tray and resin splinted open tray technique for a $15^{\circ}$ angled 3-implant model Material and methods: A dental stone master model with 3 linearly positioned implant analogue and a reference framework which was passively fitted to it were fabricated. The center analogue was perpendicular to the plane of model and the outer analogues had a $15^{\circ}$angulation forward or backward. 10 closed tray impressions, 10 resin splinted open tray impressions, 10 abutment-resin framework cementation impressions and 10 abutment-metal framework cementation impressions were made with additional silicone material and poured with dental stone. A light microscope with image processing was used to record the vertical gap dimension between reference framework and analogue of duplicated cast made with each 4 impression techniques. Statistical analysis used one-way ANOVA with post-hoc tests Tukey test of .05 level of significance Results: Significant difference in the vertical gap dimension was found between closed tray technique; 74.3 (${\pm}33.4$)${\mu}m$ and resin splinted open tray technique, and two other new technique. (P<.05) Abutment-metal framework cementation technique;42.5 (${\pm}11.9$)${\mu}m$ was significantly different from resin splinted open tray technique. (P<.05) Abutmentresin framework cementation technique;51.0 (${\pm}14.1$)${\mu}m$ did not differ significantly from resin splinted open tray technique;50.3 (${\pm}16.9$)${\mu}m$. (P>.05) Conclusion: Within limitations of this study, the accuracy of implant level impressions of resin splinted open tray technique was superior to that of closed tray technique. A new technique using abutment and metal framework cementation was more accurate than resin splinted open tray technique.