• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.3
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• pp.184-193
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• 2016

Purpose: To evaluate marginal leakage of bulk fill flowable composite resin filling with different curing time by using microcomputed tomography technology. Materials and Methods: 30 previously extracted human molars were randomly divided into 6 groups based upon restorative system and different curing time. Class II cavities (vertical slot cavities) were prepared. An individual metallic matrix was used to build up the proximal wall. The SonicFill or SureFil SDR flow was inserted into the preparation by using 1 bulk increment, followed by light polymerization for different curing times. The different exposure times were 20, 40, and 60 seconds. All specimens were submitted to 5,000 thermal cycles for artificial aging. Micro-CT scanning was performed by using SkyScan 1272. One evaluator assessed microleakage of silver nitrated solution at the resin-dentin interface. The 3D image of each leakage around the restoration was reconstructed with CT-Analyser V.1.14.4. The leakage was analyzed with the Mann-Whitney test. Results: Significant differences were observed between the light curing times, but no significant differences were found between the bulk fill composite resins. Increasing in the photoactivation time resulted in greater microleakage in all the experimental groups. Those subjected to 60 seconds of light curing showed higher microleakage means than those exposed for 20 seconds and 40 seconds. Conclusion: Increasing the photoactivation time is factor that may increase marginal microlekage of the bulk fill composite resins. Further, micro-CT can nondestructively detect leakage around the resin composite restoration in three dimensions.

• Journal of Yeungnam Medical Science
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• v.8 no.1
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• pp.53-62
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• 1991

Experiments were performed in mice(Balb/C) to support the basic efficacy of the human immunoglobulin (IgG) preparation. The antibacterial activity of IgG purified from human sera was examined with or without the quinolone agent, ciprofloxacin(CPFX), against Pseudomonas aeruginosa isolated from clinical specimens. Results were as follows: Antibacterial activities in terms of the percentage of survivors, after administration of Ps. aeruginosa into mouse intraperitoneal cavity were in the following order, single IgG group, CPFX administration after IgG pretreatment group, IgG and CPFX combined administration group and CPFX alone group. The number of living bacteria was monitored in blood and liver tissue of mice infected with Ps. aeriginosa and treated by IgG administration. The increase of living bacteria in liver was more drastic than that in blood. Leukocytosis was observed in mice injected with IgG, excluding those only with ciprofloxacin, after 8 hours of administration to see a decrease to normal number of bacteria after 18 hours. No significant difference was noticed between pretreatment group and post treatment group. In vitro susceptibility test of IgG against Ps. aeruginosa, minimal inhibitory concentration(MIC) was $250{\mu}g/ml$, resistant to IgG, regardless of a combined administration with CPFX. In vitro test revealed that the IgG itself did not have anti-Ps. aeruginosa activity.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.780-788
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• 1995

The purpose of this study was to compare the apical seal following root canal shaping by different methods. From fourty extracted mandibular 1st and 2nd molars, fourty mesial roots whose canals have some degree of curvature were selected. The mesiobuccal root portion including mesiobuccal portion of a crown was sectioned in each molar. After access cavity preparation for the mesiobuccal canal, working length was determined with # 10 K-file. The sectioned roots were implanted in acrylic resin block and randomly divided into four groups. The canals of group I were shaped by step-down/balanced force, group II by stepdown/step-back, group III by step-back and group IV by conventional method. All of the shaped canals were obturated by Thermafil method and access cavities were filled with IRM. The roots were removed from acrylic resin block and placed in 100 % humidity for 7days. Except the root surfaces of apical 2mm, the root surfaces were nail-varnished 3 times. After the roots were placed in 700 torr vacuum pressure for 15 minutes, they were immersed in 2% methylene blue solution for 4 days. Nail varnishes were removed with acetone. After that, the roots were decalcified in 5 % nitric acid and dehydrated with alcohol series. Transparent specimens were made by methyl salicylate and the quality of apical seal was assessed by measuring the leakage linearly. The results were as follows. 1. The leakage in canals shaped by step-down/balanced force method was significantly less than that in canals shaped by step-back method(P<0.05) and was less but not statistically than that in canals shaped by step-down/step-back method (P>0.05). 2. The leakage in canals shaped by step-down/step-back method was less than that in canals shaped by step-back method, but there was no statistical significance(P>0.05). 3. The leakage in canals shaped by conventional method was significantly more than that in canals shaped by step-down/balanced force, step-down/step-back and step-back method (P<0.05).

• Restorative Dentistry and Endodontics
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• v.44 no.3
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• pp.33.1-33.12
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• 2019

Objectives: To evaluate the influence of the restorative technique on the mechanical response of endodontically-treated upper premolars with mesio-occluso-distal (MOD) cavity. Materials and Methods: Forty-eight premolars received MOD preparation (4 groups, n = 12) with different restorative techniques: glass ionomer cement + composite resin (the GIC group), a metallic post + composite resin (the MP group), a fiberglass post + composite resin (the FGP group), or no endodontic treatment + restoration with composite resin (the CR group). Cusp strain and load-bearing capacity were evaluated. One-way analysis of variance and the Tukey test were used with ${\alpha}=5%$. Finite element analysis (FEA) was used to calculate displacement and tensile stress for the teeth and restorations. Results: MP showed the highest cusp (p = 0.027) deflection ($24.28{\pm}5.09{\mu}m/{\mu}m$), followed by FGP ($20.61{\pm}5.05{\mu}m/{\mu}m$), CR ($17.62{\pm}7.00{\mu}m/{\mu}m$), and GIC ($17.62{\pm}7.00{\mu}m/{\mu}m$). For load-bearing, CR ($38.89{\pm}3.24N$) showed the highest, followed by GIC ($37.51{\pm}6.69N$), FGP ($29.80{\pm}10.03N$), and MP ($18.41{\pm}4.15N$) (p = 0.001) value. FEA showed similar behavior in the restorations in all groups, while MP showed the highest stress concentration in the tooth and post. Conclusions: There is no mechanical advantage in using intraradicular posts for endodontically-treated premolars requiring MOD restoration. Filling the pulp chamber with GIC and restoring the tooth with only CR showed the most promising results for cusp deflection, failure load, and stress distribution.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.5
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• pp.339-348
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• 2022

Background: To compare the anesthetic efficacy of supplemental buccal infiltration (BI) (1.7 ml) versus intraligamentary (IL) injection containing 0.4 ml of 4% articaine with 1:100.000 epinephrine after an inferior alveolar nerve block (IANB) with 1.7 ml 2% lidocaine in the first and second mandibular molars diagnosed with irreversible pulpitis (IP). Methods: One hundred subjects diagnosed with IP of either the mandibular first (n = 50) or second molars (n = 50) and failed profound anesthesia following an IANB were selected. They randomly received either the IL or BI techniques of anesthesia. Pain scores on a 170 mm Heft-Parker visual analog scale were recorded initially, before, and during supplemental injections. Furthermore, pulse rate was measured before and after each supplemental injection. During the access cavity preparation and initial filing, no or mild pain was assumed to indicate anesthetic success. The chi-square test, Mann-Whitney U test, and independent samples t-test were used for the analyses. Results: The overall success rates were 80% in the IL group and 74% in the BI group, with no significant difference (P = 0.63). In the first molars, there was no significant difference between the two techniques (P = 0.088). In the second molars, IL injection resulted in a significantly higher success rate (P = 0.017) than BI. IL injection was statistically more successful (P = 0.034) in the second molars (92%) than in the first molars (68%). However, BI was significantly more successful (P = 0.047) in the first molars (88%) than in the second molars (64%). The mean pulse rate increase was significantly higher in the IL group than in the BI group (P < 0.001). Conclusions: Both the IL and BI techniques were advantageous when used as supplemental injections. However, more favorable outcomes were observed when the second molars received IL injection and the first molars received BI.

• Journal of Veterinary Science
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• v.25 no.2
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• pp.29.1-29.11
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• 2024

Background: Preservation of biological tissues has been used since ancient times. Regardless of the method employed, tissue preservation is thought to be a vital step in veterinary surgery teaching and learning. Objectives: This study was designed to determine the usability of chemically preserved cadaveric equine heads for surgical teaching in veterinary medicine. Methods: Six cadaveric equine heads were collected immediately after death or euthanasia and frozen until fixation. Fixation was achieved by using a hypertonic solution consisting of sodium chloride, sodium nitrite and sodium nitrate, and an alcoholic solution containing ethanol and glycerin. Chemically preserved specimens were stored at low temperatures (2℃ to 6℃) in a conventional refrigerator. The specimens were submitted to gross and organoleptic assessment right after fixative solution injection (D0) and within 10, 20, and 30 days of fixation (D10, D20, and D30, respectively). Samples of tissue from skin, tongue, oral vestibule, and masseter muscle were collected for histological evaluation at the same time points. Results: Physical and organoleptic assessments revealed excellent specimen quality (mean scores higher than 4 on a 5-point scale) in most cases. In some specimens, lower scores (3) were assigned to the range of mouth opening, particularly on D0 and D10. A reduced the range of mouth opening may be a limiting factor in teaching activities involving structures located in the oral cavity. Conclusions: The excellent physical, histologic, and organoleptic characteristics of the specimens in this sample support their usability in teaching within the time frame considered. Appropriate physical and organoleptic characteristics (color, texture, odor, and flexibility) of the specimens in this study support the use of the method described for preparation of reusable anatomical specimens.

• Journal of Oral Medicine and Pain
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• v.30 no.3
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• pp.375-381
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• 2005

Er:YAG laser has been considered a promising alternative to dental drill and many researches indicate that adjustment to variable parameters, including water flow rate, pulse energy and pulse repetition rate, can be made to improve ablation ability and efficiency of the laser. Of these parameters, addition of water spray during irradiation has been thought to ablate dental hard tissue more rapidly and safely. The purpose of this study was to investigate tooth ablation amount by Er:YAG laser irradiation as related to varied water flow rates added and, ultimately to find the most effective water flow rate for ablation. In addition, the temperature change of pulp chamber during irradiation was also monitored on the irradiated and opposite pulpal walls, respectively. An Er:YAG laser with contact mode was employed. Extracted human molars were split into two pieces for ablation experiment. Pulse energies of 200 and 300 mJ with a pulse repetition rate of 20 Hz and 5 water flow rates (1.6, 3.0, 5.0, 7.0, and 10.0 ml/min) were applied. Each irradiation was performed for 3 seconds. According to these parameters, experimental groups were divided into 10 subgroups which consisted of 5 specimens. For temperature experiment, another 5 tooth-specimens were prepared in the manner that pulp chamber was open through access cavity preparation and two temperature-measuring probes were placed respectively on the irradiated and the opposite walls of pulp chamber. From the experiment on ablation amount related to different water flow rates, it was shown that the least water flow rate of 1.6 ml/min ablated more than any other water flow rates (p<0.000). When the irradiation for 3 seconds, combined with the pulse repetition time of 20Hz and the water flow rate of 1.6 ml/min was done to tooth specimen, the temperature rise was not noticeable both on the irradiated and the opposite pulpal walls (less than 3$^{\circ}C$) and there was no significant difference in temperature rise between the two pulse energies, 200 and 300 mJ. From the results of this study, it is suggested that tooth ablation with Er:YAG laser can be done effectively and safely at a energy between 200 and 300 mJ/pulse and a pulse repetition rate of 20 Hz when the lasing is conjugated with the water flow rate of 1.6ml/min.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.653-660
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• 2006

Fuji VII is a glass-ionomer cement specially targeted for early protection in erupting first and second molars. Properties of Fuji VII such as very high level of fluoride release, low viscosity and no need to preliminarily etch the substrate would be useful to erupting molars with primary pit and fissure caries or hypoplastic area for preventive goal or remineralization. The purpose of this study were to evaluate remineralization of Fuji VII glass ionomer cement and to compare with one of other restorative materials such as conventional glass ionomer cement, resin-modified glass ionomer cement, compomer and composite resin. Forty-two extracted human molars were used for this study. All teeth were immersed in demineralizing solution for 48 hours after Class V cavity preparation was made on sound proximal surface. The teeth were randomly divided into six groups and restored with Fuji VII, Fuji II, Fuji II LC improved, F2000, $Filtek^{TM}$ Z250 and control group was unrestored. The middle area with $130{\pm}20{\mu}m$ thickness was separated from specimen using microtome and demineralized area was photographed under polarized microscope. Separated area was relocated to specimen and stored in artificial saliva, After four weeks, changes of demineralized area were observed and compared to them restorated immediately. The results from the this study can be summarized as follows ; 1. Fuji VII, Fuji II, Fuji II LC improved have more prominent remineralization effect than F2000, $Filtek^{TM}$ Z250, control group. 2. No significant differences in remineralization effect are seen between Fuji VII and Fuji II, Fuji II LC improved.

• Parasites, Hosts and Diseases
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• v.27 no.3
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• pp.177-186
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• 1989

Observations were made on the differences in cell-mediated immune responses in the mice infected with strongly pathogenic Naegleria fewleyi ITMAP 359, weakly pathogenic Naegzeria jadini 0400, or non.pathogenic Naegleria gruberi EGB, respectively. Variations in cell-mediated responses and changes in antibody titers according to the duration after infection wore noted. Infections were done by dropping $5{\;}{\mu}l$ saline suspension containing $10{\times}10^4$ trophozoites cultured Bxenically in the CGVS medium into the right nasal cavity of ICR mice aging about 6~7 weeks, under the anesthesia by intraperitoneal injection of'secobarbital. Following infection, delayed type hypersensitivity(DTH) iesponses in the footpad and blastogenic responses of the mouse spleen cells using [$^3H$]-thymidine were observed on the day 1, 4, 7, 10 and 14 after infection. For the preparation of amoeba Iysates, each of cultured trophosoites were homogenized with an ultrasonicator, and centrifugated at 20,000 g. The supernatants of amoeba Iysates were used as the mitogen'and antigen for ELISA. Confanavalin A(Con. A) and lipopolysaccharide(LPS) were also used as mitogens in the blastogenic response. 1. The mice infected with N, fowleri showed the mortality rate of 75.7%. The rate was 6.2% for the N. jadini infected group, while no dead mouse was observed for N. gruberi infections. 2. In regard to DTH responses in the H. fewleri infected mice, the level increased in com- parison to the control group but declined after 7 days. An increase was also noted for the JV. jadini group after 1 day, but gradual decreases were observed through the infection period. In addition, no difference was noted between the N. gruberi infected and control groups. 3. Concerning the blastogenic response of the splenocytes, it increased after 10 days in the experimental group of N, fcwleri infection, but the differences ware not statistically significant compared with control group. It was evident that N. jadini group was not different from control group either, while there was a tendency of decrease in SV. gruberi infected group. In regard to the blastogenic response of the splenocytes by LPS, it was found that the N. fowlgri, N. jadini and N. gruberi infected groups had no differences from the control group. 4. The serum antibody titer of N. fcwleri and N. jadini infected mice increased from the day 7 and 14 after infection respectively, while the N. gruberi infected mice showed no increase. In summary of the results, it was observed that there were differences in the cell-mediated immune responses and serum antibody titers in the mice infected with strongly pathogenic JV. fowleri, weakly pathogenic N. jadini, or non.pathogenic N. gruberi, respectively.

• Restorative Dentistry and Endodontics
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• v.27 no.2
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• pp.150-157
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• 2002

One of the latest concepts in bonding are "total etch", in which both enamel and dentin are etched with an acid to remove the smear layers, and "wet dentin" in which the dentin is not dry but left moist before application of the bonding primer Ideally the application of a bonding agent to tooth structure should be insensitive to minor contamination from oral fluids. Clinically, contaminations such as saliva, gingival fluid, blood and handpiece lubricant are often encountered by dentists during cavity preparation. The aim of this study was to evaluate the effect of contamination by hemostatic agents on shear bond strength of compomer restorations. One hundred and ten extracted human maxillary and mandibular molar teeth were collected. The teeth were removed soft tissue remnant and debris and stored in physiologic solution until they were used. Small flat area on dentin of the buccal surface were wet ground serially with 400, 800 and 1200 abrasive papers on automatic polishing machine. The teeth were randomly divided into 11 groups. Each group was conditioned as follows : Group 1: Dentin surface was not etched and not contaminated by hemostatic agents. Group 2: Dentin surface was not etched but was contaminated by Astringedent$^{\circledR}$(Ultradent product Inc., Utah, U.S.A.) Group 3: Dentin surface was not etched but was contaminated by Bosmin$^{\circledR}$(Jeil Pharm, Korea.). Group 4: Dentin surface was not etched but was contaminated by Epri-dent$^{\circledR}$(Epr Industries, NJ, U.S.A.). Group 5: Dentin surface was etched and not contaminated by hemostatic agents. Group 6: Dentin sorface was etched and contaminated by Astringedent$^{\circledR}$. Group 7 : Dentin surface was etched and contaminated by Bosmin$^{\circledR}$. Group 8: Dentin surface was etched and contaminated by Epri-dent$^{\circledR}$. Group 9: Dentin surface was contaminated by Astringedent$^{\circledR}$. The contaminated surface was rinsed by water and dried by compressed air. Group 10: Dentin surface was contaminated by Bosmin$^{\circledR}$. The contaminated surface was rinsed by water and dried by compressed air. Group 11 : Dentin surface was contaminated by Epri-dent$^{\circledR}$. The contaminated surface was rinsed by water and dried by compressed air. After surface conditioning, F2000$^{\circledR}$ was applicated on the conditoned dentin surface The teeth were thermocycled in distilled water at 5$^{\circ}C$ and 55$^{\circ}C$ for 1,000 cycles. The samples were placed on the binder with the bonded compomer-dentin interface parallel to the knife-edge shearing rod of the Universal Testing Machine(Zwick Z020, Zwick Co., Germany) running at a cross head speed or 1.0 mm/min. Group 2 showed significant decrease in shear bond strength compared with group 1 and group 6 showed significant decrease in shear bond strength compared with group 5. There were no significant differences in shear bond strength between group 5 and group 9, 10 and 11.