• Journal of Korean Academy of Dental Administration
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• v.5 no.1
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• pp.31-37
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• 2017

Recently interest in infection control is increasing in hospitalsnfection control has become more important in the overall health care practiceental hospital also requires thorough infection control. There are various kinds of vectormedical clothing. Contaminated clothing of a hospital staff can be a vector of nosocomial infecton. actual case of nosocomial infecton caused by contaminated medical clothing, nursing students were measuring contamination levels of uniforms and pathogenic microorganism wdetected in front of the uniform and pocket. There is also a high risk of exposure to contamination in the dental hospital. We conducted a study to enhance awareness about infection and proper clothing management by comparing before and after contamination of clothing caused by aerosols produced during scaling. Subjects were scaling operators' uniforms in the department of dental hygiene, K University located in Daejeon. Before scaling, the uniform was sterilized by autoclavecaling was performed times in the same place (an average of 60 minutes per person, a total of 180 minutes). ive parts of the uniform (sleeves, chest, belly, thigh, edge of pants) contracted Rodak-plate for 15 seconds. After incubating the contacted Rodak-plate at 37℃ incubator, contamination levels by measuring the number of colonies. As a result, all parts increased number of colonies. ontamination order chestedge of pants thigh belly sleeves. Increase rate of colonies was also high in the order chest edge of pants thigh belly sleeves. This study showed seriousness of clothing contaminationcaused by aerol produced during scalingcontamination of clothing can be a path to nosocomial infecton. According to th study, infection control for clothing as well as dental instruments should be implemented and thorough infection control training needed for dental staff. In further researches, practical infection prevention supplementing clothing management method.

• Restorative Dentistry and Endodontics
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• v.31 no.5
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• pp.371-377
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• 2006

The purposes of this study were to assess the accuracy of measurements in pre-enlarged canals with small instruments and to compare the accuracies, in enlarged canal, with small size instruments and instruments that match the actual canal diameter using Root ZX, Bingo1020, SmarPex, and e-Magic Finder. Ten extracted teeth were embedded in an alginate model made for testing apex locators. A size 10 file was placed into the root canal until the tip of the file reached the plane of the major diameter of the foramen under a dental operating microscope at the 25 x magnification. The measurement was done with digital caliper and defined as actual length. Electronic length measurement with a size 10 file in pre-enlarged canal was done by reading the index indicating Apex of each device to gain a definite value After completion of canal enlargement to a size 45 file, each difference between actual length and electric measurement value with a size 10 and 40 files in enlarged canal was recorded as L10 and L40. The one-way ANOVA and Scheffe's multiple range tests were computed for analyze the differences among the four apex locators in the same group. The Student's t-test between L10 and L40 of each locator was done. The accuracies of electronic measurements were significantly different among the 4 devices. The file size made no difference on the accuracy of electronic measurement in enlarged canal with same device. The e-Magic Finder was the most accurate device among the 4 apex locators used in this study.

• Restorative Dentistry and Endodontics
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• v.35 no.5
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• pp.374-379
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• 2010

Objectives: Nickel-titanium (Ni-Ti) rotary instruments have some unexpected disadvantages including the tendency to screw-in to the canal. The purpose of this study was to evaluate the influence of root canal curvatures on the screw-in effect of Ni-Ti rotary files. Materials and Methods: A total of 80 simulated root canals in clear resin blocks were used in the study. Canals with curvature of 0, 10, 20 and 30 degrees were instrumented with ProTaper instruments SX, S1, S2 and a ProFile of #25/0.06 to 1.0-2.0 mm beyond the initial point of root curvature. The screw-in force was measured with a specially designed device while canal was instrumented with a ProFile of #30/0.06 at a constant speed of 300 rpm. The data were subjected to one-way ANOVA and Scheffe multiple range test for post-hoc test. Results: Larger degree of canal curvature generated significantly lesser screw-in forces in all groups (p < 0.001). Conclusions: More attention needs to be paid when using rotary instruments in canals with less curvature than canals with more curvatures to prevent or reduce any accidental overinstrumentation.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.2
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• pp.210-225
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• 2004

Statement of problem: Implant screw loosening has been remained problem in restorative practices. Surface treatment of screw plays a role of preventing screw from loosening in implant screw mechanism. Purpose : The purpose of this study was to investigate surface characteristics of TiN and ZrN film ion plated screw with titanium and gold alloy screw and to evaluate wear resistance, surface roughness, and film adhesion on screw surface using various instruments. Material and methods : GoldTite screws and titanium screws provided by 3i (Implant Innovation, USA) and TorqTite screws or titanium screws by Steri-Oss (Nobel Biocare, USA) and gold screws and titanium screws by AVANA (Osstem Implant, korea) were selected. Ion plating which is much superior to other surface modification techniques was carried out for gold screws and titanium screws using Ti and Zr coating materials with nitrogen gas. Ion nitrided surface of each abutment screw was observed with field emission scanning electron microscopy (FE-SEM, micro-diamond scratch tester, vickers hardness tester, and surface roughness tester. Results : 1) The surface of gold screw and GoldTite is more smooth than ones of other kinds of non coated screw. 2) The ZrN and TiN coated surface is the more smooth than ones of other kinds of screw. 3) The hardness of TiN and ZrN coated surface showed higher than that of non coated surface. 4) The TiN coated titanium screw and ZrN coated gold screw have a good wear resistance and adhesion on the surface. 5) The surface of ZrN coated screw showed low surface roughness compared with the surface of TiN coated screw. Conclusion : It is considered that the TiN and ZrN coated screw which would prevent a screw from loosening can be applicable to implant system and confirmed that TiN and ZrN film act as lubricant on surface of screw due to decrease of friction for recycled tightening and loosening.

• Journal of Periodontal and Implant Science
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• v.43 no.6
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• pp.301-307
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• 2013

Purpose: This in vitro study was performed to assess the adherence of Porphyromonas gingivalis to a resorbable blast media (RBM) titanium surface pretreated with an ultrasonic scaler or toothbrush and to evaluate the effects of the treatment of the RBM titanium discs on the bacterial removal efficiency of brushing by crystal violet assay and scanning electron microscopy. Methods: RBM titanium discs were pretreated with one of several ultrasonic scaler tips or cleaned with a toothbrush. Then the titanium discs were incubated with P. gingivalis and the quantity of adherent bacteria was compared. The disc surfaces incubated with bacteria were brushed with a toothbrush with dentifrice. Bacteria remaining on the disc surfaces were quantified. Results: A change in morphology of the surface of the RBM titanium discs after different treatments was noted. There were no significant differences in the adherence of bacteria on the pretreated discs according to the treatment modality. Pretreatment with various instruments did not produce significant differences in the bacterial removal efficiency of brushing with dentifrice. Conclusions: Within the limits of this study, various types of mechanical instrumentation were shown to cause mechanical changes on the RBM titanium surface but did not show a significant influence on the adherence of bacteria and removal efficiency of brushing.

• Journal of Veterinary Clinics
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• v.30 no.5
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• pp.380-383
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• 2013

This clinical report describes the dental treatment of canine teeth fractures in three cats. These animals were diagnosed by oral examination and dental radiography as having fractured teeth with pulpal exposure. After endodontic treatment was completed, root canal filling material was removed from the coronal access and a trial post placement was performed. The post was permanently cemented after shortening. Teeth were etched and a bonded composite resin core formed and then shaped using rotary instruments. Fractured canine teeth were treated without any complications observed during a six-month follow-up period, proving that fractured cat canine teeth can be treated successfully with root canal therapy followed by restorative treatment with posts and composite resin.

• The Journal of the Korean dental association
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• v.52 no.12
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• pp.734-743
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• 2014

Objectives: By introduced reciprocation motion file in dentistry, dentists benefit simple canal shaping procedure and time-saving. But, reciprocation motion generates uncomfortable vibration to doctors and patients. Because there was no study about this consideration, this study compared vibration pattern and power generated from reciprocation motion motor and conventional rotary motor. Materials & Methods: One conventional rotary motor; X-Smart (Dentsply Maillefer, Ballaigues, Switzerland); and two reciprocating motors; WaveOne Motor (Dentsply Maillefer, Ballaigues, Switzerland) and X-SMART PLUS (Dentsply Maillefer, Ballaigues, Switzerland); were used in this study. Triaxial $ICP^{(R)}$ Accelerometer (Model 356A12, PCB piezotronics, New York, USA) was attached on motor's handpiece head, and was measured tri-axial vibratory acceleration with NI Sound and Vibration Assistant 2009 software (National Instruments, Texas, USA). Mean vibratory acceleration and maximum vibratory acceleration was measured on fixed position and handed position. The results of vibratory acceleration were statistically analyzed using ANOVA and multiple comparisons are made using Turkey's test at p<0.05 level. Results: Reciprocating motors showed higher mean vibratory acceleration and maximum vibratory acceleration than conventional rotary motor (p<0.05). Between reciprocating motors, X-SMART PLUS had lower mean vibratory acceleration and maximum vibratory acceleration than WaveOne Motor (p<0.05). Conclusion: Reciprocating motors generate more vibration than conventional rotary motor. Further study about effect of vibration to dentist and patient is needed. And it seems to be necessary to make a standard about vibration level in endodontic motors.

• Restorative Dentistry and Endodontics
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• v.40 no.2
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• pp.123-127
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• 2015

Objectives: Glide path preparation is recommended to reduce torsional failure of nickel-titanium (NiTi) rotary instruments and to prevent root canal transportation. This study evaluated whether the repetitive insertions of G-files to the working length maintain the apical size as well as provide sufficient lumen as a glide path for subsequent instrumentation. Materials and Methods: The G-file system (Micro-Mega) composed of G1 and G2 files for glide path preparation was used with the J-shaped, simulated resin canals. After inserting a G1 file twice, a G2 file was inserted to the working length 1, 4, 7, or 10 times for four each experimental group, respectively (n = 10). Then the canals were cleaned by copious irrigation, and lubricated with a separating gel medium. Canal replicas were made using silicone impression material, and the diameter of the replicas was measured at working length (D0) and 1 mm level (D1) under a scanning electron microscope. Data was analysed by one-way ANOVA and post-hoc tests (p = 0.05). Results: The diameter at D0 level did not show any significant difference between the 1, 2, 4, and 10 times of repetitive pecking insertions of G2 files at working length. However, 10 times of pecking motion with G2 file resulted in significantly larger canal diameter at D1 (p < 0.05). Conclusions: Under the limitations of this study, the repetitive insertion of a G2 file up to 10 times at working length created an adequate lumen for subsequent apical shaping with other rotary files bigger than International Organization for Standardization (ISO) size 20, without apical transportation at D0 level.

• Restorative Dentistry and Endodontics
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• v.42 no.3
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• pp.224-231
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• 2017

Objectives: To determine the actual revolutions per minute (rpm) values and compare the cyclic fatigue life of Reciproc (RPC, VDW GmbH), WaveOne (WO, Dentsply Maillefer), and TF Adaptive (TFA, Axis/SybronEndo) nickel-titanium (NiTi) file systems using high-speed camera. Materials and Methods: Twenty RPC R25 (25/0.08), 20 WO Primary (25/0.08), and 20 TFA ML 1 (25/0.08) files were employed in the present study. The cyclic fatigue tests were performed using a dynamic cyclic fatigue testing device, which has an artificial stainless steel canal with a $60^{\circ}$ angle of curvature and a 5-mm radius of curvature. The files were divided into 3 groups (group 1, RPC R25 [RPC]; group 2, WO Primary [WO]; group 3, TF Adaptive ML 1 [TFA]). All the instruments were rotated until fracture during the cyclic fatigue test and slow-motion videos were captured using high-speed camera. The number of cycles to failure (NCF) was calculated. The data were analyzed statistically using one-way analysis of variance (ANOVA, p < 0.05). Results: The slow-motion videos were indicated that rpm values of the RPC, WO, and TFA groups were 180, 210, and 425, respectively. RPC ($3,464.45{\pm}487.58$) and WO ($3,257.63{\pm}556.39$) groups had significantly longer cyclic fatigue life compared with TFA ($1,634.46{\pm}300.03$) group (p < 0.05). There was no significant difference in the mean length of the fractured fragments. Conclusions: Within the limitation of the present study, RPC and WO NiTi files showed significantly longer cyclic fatigue life than TFA NiTi file.

• Restorative Dentistry and Endodontics
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• v.44 no.2
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• pp.19.1-19.9
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• 2019

Objectives: The purpose of this study was to evaluate the cyclic fatigue, bending resistance, and surface roughness of EdgeEvolve (EdgeEndo) and ProTaper Gold (Dentsply Tulsa Dental Specialties) nickel-titanium (NiTi) rotary files. Materials and Methods: The instruments (n = 15/each) were tested for cyclic fatigue in single- ($60^{\circ}$ curvature, 5-mm radius) and double-curved (coronal curvature $60^{\circ}$, 5-mm radius, and apical curvature of $30^{\circ}$ and 2-mm radius) artificial canals. The number of cycles to fracture was calculated. The bending resistance of both files were tested using a universal testing machine where the files were bent until reach $45^{\circ}$. Scanning electron microscopy and x-ray energy-dispersive spectrometric analysis were used for imaging the fractured segments, while the atomic force microscope was used to quantify the surface roughness average (Ra). Results: EdgeEvolve files exhibited higher cyclic fatigue resistance than ProTaper Gold files in single- and double-curved canals (p < 0.05) and both files were more resistant to cyclic fatigue in single-curved canals than double-curved canals (p < 0.05). EdgeEvolve files exhibited significantly more flexibility than did ProTaper Gold files (p < 0.05). Both files had approximately similar Ni and Ti contents (p > 0.05). EdgeEvolve files showed significantly lower Ra values than ProTaper Gold files (p < 0.05). Conclusions: Within the limitation of this study, EdgeEvolve files exhibited significantly higher cyclic fatigue resistance than ProTaper Gold files in both single- and double-curved canals.