PURPOSE: The purpose of this study was to measure the tightening torque for dental implant in dental laboratory and to analyze of the effects of different tightening torque. MATERIALS AND METHODS: The tightening torque for dental implant in dental laboratory were measured by digital torque gauge. The length of abutment and analog were measured as tightening torque of manufacturer's instructions and the measured value. And the data were statically analyzed. RESULTS: The mean tightening torque of implant screw in dental laboratory was 1.563 +/- 0.332 Ncm. The external type implant system of total length were showing no significant differences but the internal type implant system had difference significant (P < 0.05) when compared with tightening torque. CONCLUSION: The implant prosthesis should be made under manufacturer's instructions especially as tightening torque of screw. For the fidelity of implant prosthesis, dental technician should learn how to use the torque gauge.
Dental Implants ; Dental Prosthesis ; Dental Technicians ; Humans ; Laboratories, Dental* ; Prostheses and Implants ; Torque*

PURPOSE: The purpose of this study was to evaluate the transmission of candida in denture by dental polishing lathe. MATERIALS AND METHODS: Maxillary complete dentures made from the same model were infected with Candida albicans. Polishing wheels were keep in various chlorhexidine solution and distilled water for an hour. The infected dentures were polished by prepared dental polishing lathe with sterile pumice and distilled water. And then sterile maxillary complete dentures were polished with same method. Polishing surface was wiped with a cotton swab and the sample was regrown for checking Candida albicans. RESULTS: All polishing wheel with chlorhexidine resist fungal infection. But the polishing wheel with distilled water is infected with Candida albicans. CONCLUSION: A chlorhexidine is highly efficient in fungal infection prevention on dental polishing lathe.
Candida albicans* ; Candida* ; Chlorhexidine* ; Dental Polishing* ; Denture, Complete ; Dentures ; Methods ; Water

PURPOSE: The purpose of this study was to evaluate the properties of a porous zirconia scaffold coated with bioactive materials and compare the in vitro cellular behavior of MC3T3-E1 preosteoblastic cells to titanium and zirconia disks and porous zirconia scaffolds. MATERIALS AND METHODS: Titanium and zirconia disks were prepared. A porous zirconia scaffold was fabricated with an open cell polyurethane disk foam template. The porous zirconia scaffolds were coated with beta-TCP, HA and a compound of beta-TCP and HA (BCP). The characteristics of the specimens were evaluated using scanning electron microscopy (SEM), energy dispersive x-ray spectrometer (EDX), and x-ray diffractometry (XRD). The dissolution tests were analyzed by an inductively coupled plasma spectrometer (ICP). The osteogenic effect of MC3T3-E1 cells was assessed via cell counting and reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: The EDX profiles showed the substrate of zirconia, which was surrounded by the Ca-P layer. In the dissolution test, dissolved Ca2+ ions were observed in the following decreasing order; beta-TCP > BCP > HA (P<.05). In the cellular experiments, the cell proliferation on titanium disks appeared significantly lower in comparison to the other groups after 5 days (P<.05). The zirconia scaffolds had greater values than the zirconia disks (P<.05). The mRNA level of osteocalcin was highest on the non-coated zirconia scaffolds after 7 days. CONCLUSION: Zirconia had greater osteoblast cell activity than titanium. The interconnecting pores of the zirconia scaffolds showed enhanced proliferation and cell differentiation. The activity of osteoblast was more affected by microstructure than by coating materials.
Cell Count ; Cell Differentiation ; Cell Proliferation ; Ions ; Microscopy, Electron, Scanning ; Osteoblasts ; Osteocalcin ; Plasma ; Polyurethanes ; RNA, Messenger ; Titanium

In patients with severely resorbed alveolar bone, it is difficult to gain retention in denture. Lack of retention makes denture unstable and lead to trouble in using denture. Suction denture seals the entire denture border with movable mucosa and this sealing mechanism forms negative pressure beneath the denture and produce higher retention and stability to denture. In this case, 4 edentulous patients visited for lack of retention with dentures. Considering their high expectation with retention, suction denture concept was used to fabricate retentive and stable denture. The purpose of this case report is to compare and analyze the considerations of suction denture restorations in edentulous patients.
Denture, Complete ; Dentures ; Humans ; Mucous Membrane ; Rehabilitation ; Suction

Purpose: The purpose of this study was to examine effects of culture conditions on the growth and antibacterial activity of Streptococcus salivarius K12. Materials and Methods: S. salivarius K12 was cultivated in medium containing animal and plant protein or in medium of neutral and acidic conditions. The growth of S. salivarius K12 was measured every 2 hours by a spectrophotometer. The antimicrobial activity of S. salivarius K12 against Streptococcus mutans and Porphyromonas gingivalis was investigated by the susceptibility assay using the spent culture medium. Results: the growth of S. salivarius K12 showed faster in medium containing plant protein and neutral pH condition. The antimicrobial and antifungal activity of S. salivarius K12 appeared stronger in medium containing plant protein than animal proteins. Conclusion For application of S. salivarius K12 to bacterial oral disease, co-substances may be needed for S. salivarius K12 to colonize in the oral cavity and enhance the antimicrobial activity.

Purpose: The purpose of this study was to evaluate the shear bond strength of various 3D printed denture base resins and the conventional denture base resin to various denture relining materials. Materials and Methods: For denture base materials, a heatcured (Vertex RS) and two types of 3D printed DENTCA Denture base II, NextDent TM Base) were used. And 4 types denture relining materials (Tokuyama Rebase II fast, Kooliner, Denture Liner, Denture Liner, Lang Jet Denture Repair Kit) with different components were used. It was classified into 12 groups. Adhesion was performed between the resin base and the relining materials in accordance with ISO/TS 11405 standard. The shear bonding strength was measured, and then the adhesion interface was observed with a stereoscopic microscope and a scanning electron microscope. The fracture pattern was investigated through the analysis of the fragment. Results: In the 3D printed denture resin group, the shear bonding strength with relining materials was significantly lower than that of the heat-cured resin group (P < 0.05). The group of polymethyl methacrylate -based relining materials, high shear bonding strength was shown regardless of the type of denture. As for the fracture pattern, adhesive fracture appeared in most groups, and cohesive, mixed fracture appeared in some groups. Conclusion The polymethyl methacrylate -based denture relining materials showed high shear bonding strength values compared to other denture relining materials. But, for direct methods, it is considered advantageous in terms of shear bonding strength to use a isobutyl methacrylate-based denture relining materials.

The aim of this study was to investigate effect of zirconia on osseointegration and Surface appearance by surface treatments using various acid solution. Materials and Methods: The prepared zirconia disks were treated with hydrofluoric acid solution and photo-assisted etching under various condition. The surface was analyzed by SEM and the surface roughness was analyzed by using surface profiler. The osteogenic effect of MC3T3-E1 cells was assessed via fluorescent staining observation and reverse transcriptase-polymerase chain reaction (RT-PCR). Results: Various roughness were obtained according to the surface treatment method. The surface roughness increased in the group treated with hydrofluoric acid solution, but that had week network structure. In the method using photo-assisted etching, the surface roughness increased in micro units. Cell reaction showed better results in the photo-assisted etching group than in the hydrofluoric acid-treated group (P < 0.05). And it showed even osteoblastic cell distribution in photo-assisted etching group. Conclusion: As a result, the photo-assisted etching method is more effective than the simple acid solution treatment for zirconia treatment for osseointegration.

In severe cases of denture stomatitis, antifungal drugs are sometimes ineffective. This case is a 72-year-old patient who was prescribed fluconazole for five months but had no improvement in symptoms. After re-diagnosis, medication was performed, and temporary dentures were fabricated for oral rehabilitation. This report describes that microbiological analysis and adjuvant therapy can be helpful, in case does not improve symptoms even with continuous medication of antifungal agent.

Purpose: Various methods have been attempted to overcome limitations of physical characteristics of 3D-printed dentures; among them a novel method of increasing fracture strength by adding fine particles into the resin has been found to be effective. However, there are still limited research on the effect of these particles on the bond strength between the printed resin and denture relining materials. The purpose of this study is to compare the shear bond strength between the 3D-printing denture base resin and various relining materials when micro-particles on the surface of the resin are removed. Materials and Methods: 63 µm-sized silica microgels were mixed into 3D-printing denture base resin to make groups of weight ratio of 2 wt% and 3 wt%. After printing all 3 groups, including the control group, an HF etching solution was applied to dissolve the silica micro-particles on the surface. Three kinds of relining materials, Tokuyama Rebase II normal, KOOLINER, and ProBase Cold were attached to the surface. The shear bond strengthvalues and the failure modes for each group were analyzed. Results: The shear bond strength showed the largest average value inthe control group, in which silica was not mixed, among all three relining materials. Also, there were significant differences between specimens with different weight ratios. The largest value was measured in ProBase Cold, and the main failure mode was adhesive failure in all groups. Conclusion The shear bond strength was significantly reduced when the silica micro-particles on the surface were removed from the 3D printing denture base resin.

With the advancement of Computer-Aided Design/Computer-Aided Manufacturing (CAD-CAM) technology, fabrication of dentures using this technology has gained popularity. As one of CAD-CAM technologies, digital complete denture system has been introduced, which fabricates complete dentures using subtractive manufacturing of monolithic block containing both the color of a denture base and an artificial tooth. In this case, two pairs of upper and lower dentures were fabricated for two patients. Two pairs of complete dentures were fabricated for a 74-year-old male and a 73-year-old female respectively by conventional denture fabrication method and digital method of milling. To obtain a digital complete denture, monolithic block (Ivotion, Ivoclar Vivadent, Schaan, Liechtenstein) was chosen for the materials to fabricate the digital complete dentures. An individual tray was designed using CAD software and manufactured by 3D printing technique. The final impression and interocclusal relationship were recorded using the fabricated individual tray. The final impression was scanned, and the complete denture design and try-in denture were 3D printed using CAD-CAM software. Subsequently, the monolithic block was milled, and the final dentures were fabricated and tried on patients. Previously mentioned two patient cases compared and analyzed stability, fit, speaking, mastication, aesthetics, and patient satisfaction of two pairs of dentures: one fabricated using CAD-CAM system and the other using traditional methods. This was performed to evaluate and report the findings from both denture-making approaches.