• The Journal of Korean Academy of Prosthodontics
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• v.39 no.3
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• pp.313-318
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• 2001

Masticatory function is more important than esthetics in posterior fixed restoration. The usual technique-mounting the casts on a semi-adjustable articulator, etc. -cannot make all patients satisfied with their restorations. For example, functionally generated path technique can be an easier and more satisfactory method in the restoration of group function. These clinical reports describe various approaches for occlusal restoration of relatively simple posterior fixed protheses according to patients occlusal patterns. The 3-unit bridge restoration is one of the most popular treatment options in prosthodontics. Because dentists have much experiences of it, they restore a missing span of one tooth mechanically, that is, without special consideration. While esthetics is important in making an anterior 3-unit fixed prostheses, mastication is more focused on in posterior 3-unit bridge restoration. Many dentists are concerned about various aspects in esthetics, such as morphology of the tooth, value, chroma, hue, translucency, surface texture, etc. But they do not usually consider various methods to restore occlusion. They treat one-tooth-missing area in a similar way in spite of patients having variety of occlusal patterns. Three cases are presented here in 3 or 4-unit bridge restoration. They show some methods to restore patients' occlusal patterns.

• 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 Korean Academy of Prosthodontics
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• v.42 no.4
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• pp.412-424
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• 2004

Statement of problem: Several prosthetic options are available for the restoration of multiple adjacent implants. A passively fitting prosthesis has been considered a prerequisite for the success and maintenance of osseointegration. Passivity is a particular concern with multiple implants because of documented inaccuracies in the casting and soldering process. One way to avoid this problem is to restore the implants individually, however, the restorations of individual adjacent impants requires careful adjustment of interproximal contacts. Purpose: The purpose of this study was to compare the stress distribution pattern and amount surrounding Bicon implants with individual crowns and splinted restorations. Material and method: A photoelastic model of a human partially edentulous left mandible with 3 Bicon implants($4{\times}11mm$) was fabricated. For non-splinted restorations, individual crowns were fabricated on 3 abutments ($4{\times}0.65mm,\;0^{\circ}$, 2.0 mm post, Bicon Inc., Boston, USA) After the units were cemented, 4 levels of interproximal contact tightness were evaluated: open, ideal ($8{\mu}m$ shim stock drags without tearing), medium($40{\mu}m)$), and heavy($80{\mu}m$). Splinted 3-unit fixed partial dentures were fabricated and cemented to the model. Changes in stress distribution under simulated non-loaded and loaded conditions(7.5, 15, 30 lb) were analyzed with a circular polaricope. Results: 1. Stresses were distributed around the entire body of fin in Bicon implants. 2. Splinted restorations were useful for distribution of stress around implants especially with higher loads. 3. By increasing the contact tightness between the individually restored three implants, the stress increased in the coronal portion of implants. Conclusions: Ideal adjustment of the contact tightness was important to reduce the stresses around individually restored Bicon implants.

• Journal of Korean society of Dental Hygiene
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• v.14 no.4
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• pp.447-452
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• 2014

With the increase of esthetic demands, most patients want to have restorations which are not only functional but also esthetic. For the esthetic restoration, many ceramic systems have been introduced and applied in dentistry. Among those ceramic restorations, IPS e.max system composed of lithium disilicate glass ceramic is one of the most commonly used systems because it has strength and esthetic characteristics. IPS e.max system is divided into IPS e.max Press and IPS e.max CAD according to the manufacturing methods. IPS e.max Press is fabricated through heat-pressed technique with ceramic ingot, which is very simple. The restorations which are made using IPS e.max system can apply to 3 units restoration for the anterior teeth and premolar, and single posterior tooth restoration. Cementation is one of the most important clinic procedure for the longevity of the restorations. All ceramics are bonded by resin cements, it is classified into three groups including adhesive, self-adhesive, and conventional. Variolink N, which is an adhesive resin cement and manufactured by same company with IPS e.max, is recommended for the bonding of IPS e.max restoration. Conventional and self-adhesive resin cement is also available. The aim of this review article is to provide the understanding of material properties, production procedure and clinical application of IPS e.max system.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.1
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• pp.51-62
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• 2006

Purpose: The purpose of this study was to evaluate the pattern and the magnitude of stress distribution in the supporting tissues surrounding three different types of implants(ITI, 3i. and Bicon implant system) Material and method: Photoelastic models were made with PL-2 resin(Measurements Group, Raleigh, USA) and three implants of each kind were placed in the mandibular posterior edentulous area distal to the canine. For non-splinted restorations, individual crowns were fabricated on three titanium abutments. For splinted restorations, 3-unit axed partial dentures were fabricated. Photoelastic stress analyses were carried out to measure the fringe order around the implant supporting structure under simulated loaded conditions(15 lb. 30 lb). Conclusion: The results were as follows; 1 Regardless of the implant design, stresses were increased in the apex region of loaded implant when non-splinted restorations were loaded. While relatively even stress distribution occurred with splinted restorations. Splinting was effective in the second implant. 2. Strain around Bicon implant were lower than those of other implants, which confirmed the splinting effect. The higher the load, the more the stress occurred in supporting tissue, which was most obvious in the Bicon system. 3. Stress distribution in the supporting tissue was favorable in the ITI system. while the other side of 3i system tended to concentrate the stress in some parts.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.1
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• pp.120-131
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• 2005

Statement of problem. More than 70% of patients who need the implant supported restoration are parially edentulous. The principles of design for implant supported fixed partial denture in mandibular posterior region are many and varied. Jurisdiction for their use is usually based on clinical evaluation. There are several areas or interest regarding the design of implant supported fixed partial denture in mandibular posterior region. 1) Straight and tripod configuration in implant placement, 2) Two restoration types such as individualized and splinted restorations. Purpose. The purpose of this study was to compare the amount and distribution of stress around the implant fixtures placed in the mandibular posterior region with two different arrangements and to evaluate the effects of splinting using the photoelastic stress analysis. Material & methods. 1) Production of study model: Mandibular partially edentulous model was waxed-up and duplicated with silicone and two models were poured in stone. 2) Fixture installation and photoelastic model construction: Using surveyor(Ney, USh), 3 fixtures(two 4.0 $\times$13 mm, one 5.0$\times$10 mm, Lifecore, USA) were insta)led in straight & tripod configurations. Silicone molds were made and poured in photoelastic resin (PL-2. Measurements group, USA). 3) Prostheses construction: Four 3-unit bridges (Type III gold alloy, Dongmyung co., Korea) were produced with nonhexed and hexed UCLA abutments and fitted with conventional methods. The abutments were tightened with 30 Ncm torque and the static loads were applied at 12 points of the occlusal surface. 4) Photoelastic stress analysis : The polarizer analyzer system with digital camera(S-2 Pro, Fujifilm, Japan) was used to take the photoelastic fringes and analysed using computer analysis program. Results. Solitary hexed UCLA restoration developed different stress patterns between two implant arrangement configurations, but there were no stress transfer to adjacent implants from the loaded implant in both configurations. However splinted restorations showed lesser amount of stresses in the loaded implants and showed stress transfer to adjacent implants in both configurations. Solitary hexed UCLA restoration with tripod configuration developed higher stresses in anterior and middle implants under loading than implants with straight configurations. Splintied 3 unit fixed partial dentures with tripod configuration showed higher stress development in posterior implant under loading but there were no obvious differences between two configurations. Conclusions. The tripod configuration of implant arrangement didn't show any advantages over the straight configuration. Splinting of 3 unit bridges with nonhexed UCLA abutments showed less stress development around the fixtures. Solitary hexed UCLA restoration developed tilting of implant fixture under offset loads.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.585.1-585
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• 2001

The use of flowable composite resins as liners in class II packable composite resins has been suggested by some manufacturers. However, the contributions of this technique are unproven. Objectives: The aim of this study was to compare the gingival microleakage in class II packable composite restorations with or without the use of flowable composite resins as liners.. Method: Slot cavities were prepared on both proximals of 80 extracted human molars and randomly assigned to 8 groups of 20 each.(중략)

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.579-579
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• 2001

One of the most important factors for the clinical success of adhesive posterior restorations is marginal adaptation. This property is very closely related to mechanical properties and to the shrinkage behavior of composite materials. Most of modem composite materials are light-cured. This is why the first part of this lecture will be confined to our recent research on light curing, such as plasma polymerization, LED polymerization and the power of modem halogen lamps. In the second part of the lecture the shrinkage properties such as dimensional shrinkage and shrinkage forces of different light curing materials and during different curing procedures will be discussed. Finally, in the third part of the lecture, marginal adaptation before and after loading in different cavity classes and by using different restorative techniques and curing procedures will be presented. Data will also be given on wear resistance, abrasiveness against opposing cusps and postcuring of composite materials.(omitted)

• Journal of Periodontal and Implant Science
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• v.33 no.3
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• pp.383-393
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• 2003

The aim of this retrospective study was to compare the amount of marginal bone loss between upper anterior area and upper posterior area with 71 upper single-tooth restorations on 2 stage machined $Br{{\aa}}nemark$ implants since Jan 1995. The second aim was to compare the bone defect group which had dehiscence and fenetration and the others in the upper anterior region. The results were as follows. 1. The most frequent reason of missing tooth in the upper anterior region was trauma by 61%. While upper posterior region showed various reasons such as congenital missing, advanced periodontitis, trauma. 2. Peri-implantitis with fistula occurred 1 of 41 implants in the upper anterior group in 1 year after loading and 2 of 32 implants in the upper posterior group failed before loading. The 1 year success rate of upper anterior group was 97.56 %, and 93.75 % for upper posterior group. 3. The mean marginal bone loss in the upper anterior group was 0.44${\pm}$0.25 mm, while 0.57${\pm}$0.32 mm in the upper posterior group. There was statistically significant difference in the amount of mean marginal bone loss (P${\pm}$0.10 mm at one year, and 0.48${\pm}$0.26 mm for the control group. No statistically significant difference of mean marginal bone loss was showen between bone defect group and the others at implantation. According to the results, the upper anterior region showed less marginal bone loss than the upper posterior region. In case of missing single upper tooth, careful consideration on recipient residual ridge to determine proper implant diameter and length, sufficient healing time, proper loading would lead to implant success. Single tooth implants in the maxilla seemed to be an alternative to fixed partial dentures without damage to adjacent teeth.

• Journal of Periodontal and Implant Science
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• v.50 no.2
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• pp.97-105
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• 2020

Purpose: The present retrospective clinical study aimed to evaluate and compare the clinical and radiographic parameters, complications, and satisfaction in patients who received fixed prostheses supported by narrow-diameter implants (NDIs) in the anterior and posterior jaw. Methods: Patients aged ≥30 years who had NDI-supported fixed prostheses in the anterior or posterior region of either jaw for at least 2 years were included. Complications such as chipping of the crown; loosening or fracture of the screw, crown abutment, or implant; and loss of retention were recorded. Clinical peri-implant outcomes and crestal bone loss (CBL) were measured. A questionnaire was used to record responses regarding the aesthetics and function of the fixed restorations. Analysis of variance was used to assess the significance of between-group mean comparisons. The log-rank test was performed to analyze the influence of location and prosthesis type on technical complications. Results: Seventy-one patients (mean age: 39.6 years) provided informed consent with a mean follow-up duration of 53 months. Only bleeding on probing showed a statistically significant difference between NDIs in the anterior and posterior regions. The complication rate for NDIs in the posterior region was significantly higher than that for NDIs in the anterior region (P=0.041). For NDIs, CBL was significantly higher around splinted crowns than single crowns (P=0.022). Overall mean patient satisfaction was 10.34±3.65 on a visual analogue scale. Conclusions: NDIs in the anterior and posterior jaws functioned equally well in terms of periimplant soft and hard tissue health and offered acceptable patient satisfaction and reasonable complication rates.