PURPOSE: The purpose of this study was to investigate the diametral tensile strength of polymer-based temporary crown and fixed partial denture (FPD) materials, and the change of the diametral tensile strength with time. MATERIAL AND METHODS: One monomethacrylate-based temporary crown and FPD material (Trim) and three dimethacrylate-based ones (Protemp 3 Garant, Temphase, Luxtemp) were investigated. 20 specimens (the empty set 4 mm x 6 mm) were fabricated and randomly divided into two groups (Group I: Immediately, Group II: 1 hour) according to the measurement time after completion of mixing. Universal Testing Machine was used to load the specimens at a cross-head speed of 0.5 mm/min. The data were analyzed using one-way ANOVA, the multiple comparison Scheffe test and independent sample t test (alpha = 0.05). RESULTS: Trim showed severe permanent deformation without an obvious fracture during loading at both times. There were statistically significant differences among the dimethacrylate-based materials. The dimethacrylate-based materials presented an increase in strength from 5 minutes to 1 hour and were as follows: Protemp 3 Garant (23.16 - 37.6 MPa), Temphase (22.27 - 28.08 MPa), Luxatemp (14.46 - 20.59 MPa). Protemp 3 Garant showed the highest value. CONCLUSION: The dimethacrylate-based temporary materials tested were stronger in diametral tensile strength than the monomethacrylate-based one. The diametral tensile strength of the materials investigated increased with time.
Acrylic Resins ; Bisphenol A-Glycidyl Methacrylate ; Collodion ; Composite Resins ; Crowns ; Denture, Partial, Fixed ; Methacrylates ; Polymethacrylic Acids ; Tensile Strength

PURPOSE: The objective of this study was to evaluate the influence of various cement types on the stress distribution in monolithic zirconia crowns under maximum bite force using the finite element analysis. MATERIALS AND METHODS: The models of the prepared #46 crown (deep chamfer margin) were scanned and solid models composed of the monolithic zirconia crown, cement layer, and prepared tooth were produced using the computer-aided design technology and were subsequently translated into 3-dimensional finite element models. Four models were prepared according to different cement types (zinc phosphate, polycarboxylate, glass ionomer, and resin). A load of 700 N was applied vertically on the crowns (8 loading points). Maximum principal stress was determined. RESULTS: Zinc phosphate cement had a greater stress concentration in the cement layer, while polycarboxylate cement had a greater stress concentration on the distal surface of the monolithic zirconia crown and abutment tooth. Resin cement and glass ionomer cement showed similar patterns, but resin cement showed a lower stress distribution on the lingual and mesial surface of the cement layer. CONCLUSION: The test results indicate that the use of different luting agents that have various elastic moduli has an impact on the stress distribution of the monolithic zirconia crowns, cement layers, and abutment tooth. Resin cement is recommended for the luting agent of the monolithic zirconia crowns.
Bite Force ; Computer-Aided Design ; Crowns* ; Dental Cements ; Dental Stress Analysis ; Finite Element Analysis* ; Glass ; Glass Ionomer Cements ; Polycarboxylate Cement ; Resin Cements ; Tooth ; Zinc Phosphate Cement ; Zirconium

Implant treatment, which was first attempted in fully edentulous patients, is now widely used in partially edentulous, and a single tooth missing patients. Moreover, implant treatment has become an essential treatment modality in modern dentistry. The material of fabricating implant prostheses has also become more diverse than before, one of which is the use of high-performance polymers. The frequency of using high-performance polymers, which have been used in the medical field, is also increased in the dental field compared to the past. In the first case, a PEKK abutment and a PFG crown (cement-screw-retaining type) were fabricated in the lower left second premolar, and in the second case, a PEKK abutment and a monolithic zirconia crown (cement-screw-retaining type) were fabricated in the missing upper left first molar, and in the third case two PEKK abutments and a splinted PFM crowns (cement-screw-retaining type) were fabricated and connected to the upper right first and second molar implants. Through these procedures the patients obtained esthetically and functionally satisfactory results after 4 years of follow-up.

In the case of excessively worn dentition, there is often insufficient space for the prosthesis, and if physiologically acceptable, the prosthesis can be fabricated by increasing the vertical dimension of occlusion. Various methods have been introduced to determine the vertical dimension of occlusion. Clinicians have to choose a method that can comfort the patient among several methods. A removable appliance can be used as a reversible method to ensure that the determined vertical dimension of occlusion does not cause physiological problems. When making impressions of many teeth, it is often difficult to make accurate impressions at once. In this case, after making an accurate impression of the individual teeth, a transfer coping was made and a pickup impression was taken in the oral cavity to create a master cast. In this case, a fixed partial denture was fabricated and full mouth rehabilitation was performed by increasing the vertical dimension of occlusion in a patient with excessively worn dentition and lack of space for restoration. As a result of follow-up of the patient for 7 years, satisfactory results were obtained both esthetically and functionally.

Edentulous patients with severe alveolar bone resorption have trouble with using traditional complete denture. In order to overcome these problems, implant-retained overdenture was developed. SFI-bar(R) system can save time and cost compared to other existing bar systems which need complicated laboratory procedures because it can be adjusted directly in a patient's mouth. A 55-year-old male, who had experienced a fractured lower old implant-retained overdenture, wanted a durable and painless denture. The fractured Locator(R) attachments were removed and edentulous mandible was restored with SFI-bar(R). A 77-year-old female with a medical history of the Parkinson's disease and severely absorbed alveolar bone of mandible, wanted to wear a retentive mandibular denture without pain. After placing two implants in front of mental foramen, two adaptors were connected to two implants and a tube bar was connected to the adaptors. A female part fitted to the bar was attached to the new denture. These clinical reports describe two-implant-retained overdenture using the SFI-bar(R) system in mandibular edentulous patients. Since the patients were satisfied esthetically and functionally during 2 years' observation, we would like to report cases.
Aged ; Bone Resorption ; Dental Implants ; Denture, Complete ; Denture, Overlay* ; Dentures ; Female ; Humans ; Male ; Mandible ; Middle Aged ; Mouth ; Parkinson Disease

Purpose: The purpose of present study was to evaluate the effect of changing structural stability of wax disc on the fit of prosthesis when the milling proceeded in order. Materials and methods: Prepared maxillary left first molar was used to fabricate a Ni-Cr alloy reference model. This was scanned to design crown and then wax pattern was milled, invested and cast to fabricate prosthesis. The wax patterns located in a row centrally within a single wax disc were set into a total of five groups ranging from WM1 group that was first milled to WM5 group that was last milled and the number of each group was set as 10. Silicone replica technique was used to measure the marginal gap, axial internal gap, line angle internal gap, occlusal internal gap. Data was evaluated with one-way ANOVA with significance level set at α = .05 and then Tukey HSD test was conducted for post analysis. Results: Marginal gap measured in each group, it was 40.41 ± 2.15 µm in WM1group, 40.44 ± 2.23 µm in WM2 group, 39.96 ± 2.25 µm in WM3 group, 39.96 ± 2.48 µm in WM4 group, and 40.57 ± 2.53 µm in WM5 group. No significant difference was found between groups. The significant difference between the groups was also not found in the axial internal gap, line angle internal gap, and occlusal internal gap. Conclusion Internal and marginal fit of single crown to the sequential order of milling processing in the single machinable wax disc did not seem to be affected by the sequence.

Implant-supported overdenture is a reliable treatment option for the patients with edentulous mandible when they have difficulty in using complete dentures. Several options have been used for implant-supported overdenture attachments. Among these, bar attachment system has greater retention and better maintainability than others. SFI-Bar(R) is prefabricated and can be adjustable at chairside. Therefore, laboratory procedures such as soldering and welding are unnecessary, which leads to fewer errors and lower costs. A 67-year-old female patient presented, complaining of mobility of lower anterior teeth with old denture. She had been wearing complete denture in the maxilla and removable partial denture in the mandible with severe bone loss. After extracting the teeth, two implants were placed in front of mental foramen, and SFI-Bar(R) was connected. A tube bar was seated to two adapters through large ball joints and fixation screws, connecting each implant. The length of the tube bar was adjusted according to inter-implant distance. Then, a female part was attached to the bar beneath the new denture. This clinical report describes two-implant-supported overdenture using the SFI-Bar(R) system in a mandibular edentulous patient.
Aged ; Dental Prosthesis, Implant-Supported ; Denture, Complete ; Denture, Overlay ; Denture, Partial, Removable ; Dentures ; Female ; Humans ; Jaw, Edentulous ; Joints ; Mandible ; Maxilla ; Retention (Psychology) ; Tooth ; Welding

PURPOSE: The aim of this study was to compare the film thicknesses of several resin cements as a function of time after mixing and to examine the effect of working time on the film thicknesses. MATERIALS AND METHODS: The film thickness (microm) of 4 resin cements (n=10), 1 composite resin (Panavia F 2.0), 3 self-adhesive resin (Clearfil SA luting, Zirconite, RelyX U200) cements was measured at 20-second intervals after mixing of the cements up to 200 seconds under a load of 50 N. Linear regression was fitted to verify the effect of working time on the film thickness of each cement. Data were compared to the working time recommended by manufacturers using Wilcoxon test (alpha=.05). RESULTS: All of the materials showed a positive linear correlation between the film thickness and working time. There was no statistically significant difference between the working time based on our results and the values recommended by the manufacturers even though there was a discrepancy between those two values. CONCLUSION: The film thickness of resin cements could increase with the increase of working time. Working time to meet the ISO standard of 50-microm maximum film thickness could be different from the manufacturer's recommended value.
Linear Models ; Resin Cements ; Resins, Synthetic*

OBJECTIVES: We investigated the genotoxic effects of 40-59 nm silver nanoparticles (Ag-NPs) by bacterial reverse mutation assay (Ames test), in vitro comet assay and micronucleus (MN) assay. In particular, we directly compared the effect of cytochalasin B (cytoB) and rat liver homogenate (S9 mix) in the formation of MN by Ag-NPs. METHODS: Before testing, we confirmed that Ag-NPs were completely dispersed in the experimental medium by sonication (three times in 1 minute) and filtration (0.2 microm pore size filter), and then we measured their size in a zeta potential analyzer. After that the genotoxicity were measured and especially, S9 mix and with and without cytoB were compared one another in MN assay. RESULTS: Ames test using Salmonella typhimurium TA98, TA100, TA1535 and TA1537 strains revealed that Ag-NPs with or without S9 mix did not display a mutagenic effect. The genotoxicity of Ag-NPs was also evaluated in a mammalian cell system using Chinese hamster ovary cells. The results revealed that Ag-NPs stimulated DNA breakage and MN formation with or without S9 mix in a dose-dependent manner (from 0.01 microg/mL to 10 microg/mL). In particular, MN induction was affected by cytoB. CONCLUSIONS: All of our findings, with the exception of the Ames test results, indicate that Ag-NPs show genotoxic effects in mammalian cell system. In addition, present study suggests the potential error due to use of cytoB in genotoxic test of nanoparticles.
Animals ; Comet Assay ; Cricetinae ; Cricetulus ; Cytochalasin B ; DNA ; Female ; Filtration ; Liver ; Micronucleus Tests ; Mutagenicity Tests* ; Nanoparticles* ; Ovary ; Rats ; Salmonella typhimurium ; Silver* ; Sonication

OBJECTIVES: In order to identify the possibility of slender bitterling (SB) (Acheilognathus yamatsutae) being used as a test species for estrogenic endocrine disrupting chemicals (EEDCs), we carried out the cloning and sequence characterization of the estrogen receptor (ER). METHODS: The ER from a slender bitterling was obtained by reverse transcriptase-polymerase chain reaction (RT-PCR), 5'- and 3'-rapid amplification of cDNA ends (5'-RACE and 3'-RACE) and T-vector cloning. The expression of ER mRNA was also analyzed in six tissues (brain, liver, kidney, gill, gonad, and intestines) by real-time PCR. RESULTS: We obtained an ER from the slender bitterling. The SB ER cDNA was 2189 base pairs (bp) in length and contained a 1707 bp open reading frame that encoded 568 amino acid residues. The SB ER amino acid sequence clustered in a monophyletic group with the ERalpha of other fish, and was more closely related to zebrafish ERalpha (88% identity) than to the ERalpha of other fish. The SB ER cDNA was divided into A/B, C, D, E and F domains. The SB ER has conserved important sequences for ER functions, such as the DNA binding domain (D domain), which are consistent with those of other teleosts. CONCLUSIONS: The ER of the slender bitterling could provide basic information in toxicological studies of EEDCs in the slender bitterling.
Amino Acid Sequence ; Animals ; Base Pairing ; Clone Cells ; Cloning, Molecular ; Cloning, Organism ; DNA ; DNA, Complementary ; Endocrine Disruptors ; Estrogen Receptor alpha ; Estrogens ; Gills ; Gonads ; Kidney ; Liver ; Open Reading Frames ; RNA, Messenger ; Zebrafish