• 대한치과보철학회:학술대회논문집
• /
• 1999.11a
• /
• pp.123-123
• /
• 1999

• Journal of Periodontal and Implant Science
• /
• v.28 no.3
• /
• pp.491-505
• /
• 1998

• Journal of the korean academy of Pediatric Dentistry
• /
• v.26 no.3
• /
• pp.554-563
• /
• 1999

For the purpose of elucidating the polymerization modes of dual-cure restorative materials and comparing them with single-cure restorative materials, a study was performed on the light-cured composite resin, dual-cure composite resin, dual-cure glass ionomer cement and chemical-cure glass ionomer cement. By measuring the microhardness of each material at 0mm, 1mm and 3mm depth during initial 24 hours with predetermined interval, the state of polymerization and degree of conversion was indirectly evaluated for each material, and obtained results are as follows : 1. All of four materials tested showed significant increase in microhardness after 24hrs compared with just after curing starts. 2. In all materials except Ketac-fil, there showed a significant difference in microhardness between each depth at each time interval. 3. In the test of lap time till final curing for each material, the polymerization process was revealed to last longer in the dual-cure type materials than in single-cure type materials at 3mm depth. Based on the results above, it was demonstrated with materials of dual-cure mode that the degree of conversion increases by successive curing reactions even in the deeper layers where sufficient curing light is impermeable.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.30 no.3
• /
• pp.520-529
• /
• 2003

Proper finishing and polishing of tooth restorations enhance the esthetics and the longevity of the restored tooth. The aims of this study were to identify an appropriate polishing system for each esthetic restorative material(Z250, Heliomolar, Dyract AP, Fuji II LC), and to compare the efficiency of polishing systems(Enhance, Sof-Lex, Composite). The control group remains untouched. The results were as follows: 1. There was no significant difference of surface roughness among the materials, while a roughness value of Z250 was the lowest of all. 2. The smoothest surface was produced by Mylar sheet on all materials. The polishing procedures, however, increased a roughness value. 3. The smoothest surfaces were produced by Sof-Lex, and there was significant difference of surface roughness between Sof-Lex and Enhance systems. 4. The smoother surfaces on the control group showed many scratches after the polishing procedures in the SEM findings.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.36 no.1
• /
• pp.126-132
• /
• 2009

Injuries of permanent teeth by trauma occur frequently in childhood and adolescence. Crown fractures are as frequent as 25-76% and especially maxillary incisors are prone to fractures. There have been numerous efforts to achieve both aesthetically and functionally satisfying restoration. When a mature tooth is fractured, porcelain crown or laminate veneer could be a choice of prosthodontic treatment. However, in a case of immature permanent incisor fracture, prosthodontic treatment is more complicated due to the immaturity of the tooth. Moreover, if endodontic treatment is accompanied with the prosthodontic treatment, the treatment period is prolonged. In the past, restoration using an orthodontic band, a ready-made crown, or glass ionomer cement did not exhibit esthetically satisfying result. As restorational materials have been improved, now more esthetic restoration is possible by reattaching fractured fragments or light-curing composite resin restoration. We reports cases of patients with fractured maxillary incisors and their successful treatment results through reattachment of fractured fragments and composite resin restoration.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.32 no.1
• /
• pp.136-143
• /
• 2005

The replacement of dental restorations due to secondary caries is a continuing problem in restorative dentistry. The secondary caries can be partly prevented by using fluoride containing dental materials such as glass ionomer cement, which releases and be recharged with fluoride ion acting as a fluoride reservoir. For the purpose of investigating the behaviors of fluoride release and recharge of conventional and high viscosity glass ionomer cements, the experiment was performed on the seven specimens each from 4 kinds of materials ; 1 kind of conventional glass ionomer cement, 2 kinds of high viscosity glass ionomer cements and 1 kind of composite resin. The amount of fluoride release was measured over 7 days with pH/ion meter and fluoride specific electrode. After measuring daily fluoride release, the specimens were recharged with 2% NaF solutions for 4 minutes and measured for 3 days with recharging repeated two consecutive times. The results were as follows : 1. Significantly more fluoride was released at first day after recharge in all materials except Z-100. 2. High viscosity glass ionomer cements released more or nearly equal amount of fluoride after recharge compared with the initial release(P<0.05). 3. The fluoride release after recharge with 2% NaF solution was in order of Fuji IX, Ketac Fil, Ketac Molar, Z-100.

• Journal of the Korean Academy of Esthetic Dentistry
• /
• v.22 no.1
• /
• pp.30-46
• /
• 2013

Porcelain fused to metal crown has been used mostly over the last 50 years for restorations in dentistry. However, the patients' awareness of aesthetic aspect, biocompatibility and the problems such as an allergy to metals led to the growing interest in the 'metal free restoration'. In particular, the price of the precious metals that have been mainly used to date has risen drastically, which made them impossible to play their role as oral restorative materials anymore, and in addition, the PFM restoration has intrinsic problems of chipping and fracture. Therefore, the CAD/CAM has been drawing more attention than ever due to the popular needs for the material that is more aesthetic and stronger for restoration of the molar implant. Considerations in carrying out the full zirconia restoration are as follows: 1) strength, 2) combination work, 3) light penetrability, 4) treatment of cracks, 5) the color reproducibility of the block, 6) the abrasivity of antagonistic tooth, 7) low temperature degradation. In this presentation, the color reproducibility of the block will be discussed. One of the biggest reasons for avoiding the full zirconia restoration is that it is difficult to reproduce the natural color compared to the conventional PFM restoration. Thus, many clinicians show reluctance due to the exposure of the ugly block when the coloring on the surface is removed after occlusal adjustment. From the experience of using blocks by Zirkonzahn for more than 4 years, it is considered that these problems can be addressed to some degrees. Accordingly, how to make restorations that are well in harmony with surrounding prosthesis or natural teeth will be discussed.

• The Journal of the Korean dental association
• /
• v.58 no.7
• /
• pp.435-442
• /
• 2020

Porcelain is the first ceramic material to be introduced into dentistry. Porcelain jacket crown was introduced by Dr. Charles H Land in 1886, which was an excellent aesthetic dental restoration but has not been widely used due to high firing shrinkage and low tensile strength. Then metal-ceramic system, which combines the esthetic properties of ceramics and the mechanical properties of metals, was introduced and nowadays it is still used in dental clinical field. However, the metal-ceramic system has shown some problems, such as increased lightness by reflection of light at opaque layer, shadow beneath the gingival line due to the block-out of light by metal coping, exposure of metal in margin part, bond failure between metal and porcelain, oxidation of metal coping during firing the porcelain, etc. Recently, along with the advance of fabrication methods of dental ceramics, the all-ceramic restorations with high esthetic and mechanical properties has increased and gradually replaced metal-ceramic restorations. Especially, CAD/CAM technology has opened a new era in fabricating the dental ceramic restorations. This overview will take a look at the past, present and future possibility of the dental ceramic materials.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.26 no.4
• /
• pp.477-482
• /
• 2010

In a case of multiple posterior teeth loss, antagonistic teeth extrude to the edentulous space and compensatory occlusion on the remained anterior teeth leads to occlusal trauma. Extrusion of antagonistic teeth breaks down occlusion plane and loss of posterior support bring about severe wear of remained teeth. In this situation, it is needed to restore remained teeth and edentulous space by increasing vertical dimension to obtain prosthodontic rehabilitation space and to correct occlusion plane. In this case report, the patient had a masticatory problem with loss of posterior teeth support and an esthetic problem of shortened anterior teeth. Before the tooth preparation for the prosthodontic restoration, the patient used removable device for 2 months to increase vertical dimension reversibly. After that, he got provisional fixed restoration with irreversible tooth reduction and used it for 3 months. It had spent 5 month to evaluate the adaptation state on final restoration with incresed vertical dimension. The increasing amount was 3 mm, which was relatively in less degree and masticatory system adapted to the increased vertical dimension without any pathologic changes. Final restoration was made to have equal-intensity contacts on all teeth in a verifiable centric relations and immediate disclusion of all posterior contacts the moment the mandible moves in any direction from centric relation. In addition, metal occlusion surface on posterior teeth was applied to prevent excessive muscle activation, occlusal trauma and the porcelain fracture.

• Restorative Dentistry and Endodontics
• /
• v.31 no.6
• /
• pp.460-469
• /
• 2006

This article complies a survey on the replacement of the posterior restorations and accesses possible factors that influence the replacement of posterior restorations. The data was collected from patients that visited department of conservative dentistry from Dec 1st 2003, to Sep 3rd 2004. Teeth was restricted to posterior permanent teeth. 9 dentists recorded age, gender of patients, tooth location, cavity farm and restorative material. They rated marginal adaptation, anatomic form, secondary caries of old restoration by modified Ryge criteria system. The statistical analysis was performed with Chi square test (p < 0.05) for replacement ratio according to patients, tooth factor and One way ANOVA was performed for comparison of old restoration according to restorative material. The results were as follows; 1. The female (62%) was statistically higher ratio than the male (38%). 2. The distribution of replacement case according to age, the rate of replacement was in descending order, 20's (38.3%), 40's (16.8%), 30's (15.9%), 10's (11.1%), 50's (9.2%), 60's (8.7%). 3. The rate of replacement was 88% for molar and 12% for premolar (p $gt; 0.05). 4. The rate of replacement was 39% for maxillar and 61% for mandible (p $gt; 0.05). 5. The material of restorations was amalgam (69%), gold inlay (17%), composite resin (13%). 6. In rating system by modified Ryge criteria system on margin adaptation, there was statistically significant difference between amalgam and gold inlay. But on anatomic form and caries, there was no statistically significant difference among the material of restorations.