Comparison of the rheological properties of four root canal sealers / 国际口腔科学杂志·英文版

The flowability of a root canal sealer is clinically important because it improves the penetration of the sealer into the complex root canal system. The purpose of this study was to compare the flowabilities of four root canal sealers, measured using the simple press method (ISO 6876), and their viscosities, measured using a strain-controlled rheometer. A newly developed, calcium phosphate-based root canal sealer (Capseal) and three commercial root canal sealers (AH Plus, Sealapex and Pulp Canal Sealer EWT) were used in this study. The flowabilities of the four root canal sealers were measured using the simple press method (n=5) and their viscosities were measured using a strain-controlled rheometer (n=5). The correlation between these two values was statistically analysed using Spearman's correlation test. The flow diameters and the viscosities of the root canal sealers were strongly negatively correlated (ρ=-0.8618). The viscosity of Pulp Canal Sealer EWT was the lowest and increased in the following order: AH Plus<Sealapex<Capseal (P<0.05). All of the tested root canal sealers showed characteristic time- and temperature-dependent changes in their rheological properties. The viscosities measured using the strain-controlled rheometer were more precise than the flowabilities measured using the simple press method, suggesting that the rheometer can accurately measure the rheological properties of root canal sealers.

A retrospective study of the intentionally replanted mandibular second molars with C-shaped root canal configurations / 대한치과보존학회지

OBJECTIVES: The purpose of this retrospective study was to evaluate the success rate of intentionally replanted mandibular second molar with C-shaped canal configurations and to access the impact of preoperative periapical lesion on the success of intentional replantation procedure. MATERIALS AND METHODS: This retrospective chart review study evaluated 52 intentionally replanted mandibular second molar teeth treated at Seoul National University Dental Hospital Department of Conservative Dentistry from January 2005 to December 2007. Seventeen teeth were lost for the follow-up, and another 6 teeth did not meet inclusion criteria of C-shaped root canal configurations. Healing outcome such as success, uncertain healing, and failure after follow-up was evaluated by clinical criteria and radiographs. RESULTS: The overall success rate was 72.4% for the 29 intentionally replanted C-shaped mandibular second molars. The success rate of replanted teeth with preoperative periapical lesions was similar to that of replanted teeth which have no periapical lesions. CONCLUSIONS: Therefore, root canal treatment failure on C-shaped mandibular second molar can be predictably treated by intentional replantation regardless of the presence of periapical lesion.

The relationship of radiographic lesion size and characteristics to diagnosis of periapical cysts and granulomas / 대한치과보존학회지

The purpose of this study was to find out the relationship of radiographic lesion size, gender, age of patients and radiographic character to the diagnosis of periapical cyst and granuloma. The data was collected from 187 periapical lesions of 167 patients who undergone apical surgery at Department of Conservative Dentistry, Seoul National University Dental Hospital from 2003 to 2005. The lesion were surgically removed and send for biopsy to the Oral Pathology Laboratory. From the initial radiograph, lesion size was calculated using PiViewSTAR(R) (INFINITT, Korea) program. The obtained data were statistically evaluated using SPSS (p 0.05). 4. There was a significant correlation between the non-demarcation of the lesion and the incidence of periapical granuloma (p < 0.01).

Clinical study of shade improvement and safety of polymer-based pen type BlancTic Forte whitening agent containing 8.3% Carbamide peroxide / 대한치과보존학회지

This clinical study evaluated the whitening effect and safety of polymer based-pen type BlancTis Forte (NIBEC) containing 8.3% carbamide peroxide. Twenty volunteers used the BlancTis Forte whitening agent for 2 hours twice a day for 4 weeks. As a control, Whitening Effect Pen (LG) containing 3% hydrogen peroxide was used by 20 volunteers using the same protocol. The change in shade (DeltaE*, color difference) was measured using Shadepilot(TM) (DeguDent) before, during, and after bleaching (2 weeks, 4 weeks, and post-bleaching 4 weeks). A clinical examination for any side effects (tooth hypersensitivity or soft tissue complications) was also performed at each check-up. The following results were obtained. 1. Both the experimental and control groups displayed a noticeable change in shade (DeltaE) of over 2. No significant differences were found between the two groups (p > 0.05), implying that the two agents have a similar whitening effect. 2. The whitening effect was mainly due to changes in a and b values rather than in L value (brightness). The experimental group showed a significantly higher change in b value, thus yellow shade, than the control (p < 0.05). 3. None of the participants complained of tooth hypersensitivity or soft tissue complications, confirming the safety of both whitening agents.

Reconsideration of treatment protocol on the reduction of Enterococcus faecalis associated with failed root canal treatment / 대한치과보존학회지

Microorganism survived in the root canal after root canal cleaning and shaping procedure is a main cause of root canal treatment failure. There are several mechanisms for the bacteria to survive in the root canal after chemomechanical preparation and root canal irrigation. Bacteria organized as biofilm has been suggested as an etiology of persistent periapical lesion. Recent studies were focus on removal of Enterococcus faecalis biofilm due to the report that the persistence of this bacteria after root canal treatment may be associated with its ability to form biofilm. Several investigations demonstrated that current root canal treatment protocol including use of NaOCl, EDTA and Chlorhexidine as irrigants is quite effective in eliminating E. faecalis biofilm. However, this microorganism still can survive in inaccessible areas of root canal system and evade host immune response, suppress immune activity and produce biofilm. Up to date, there is no possible clinical method to completely get rid of bacteria from the root canal. Once the root canal treatment failure occurred, and conventional treatment incorporating current therapeutic protocol has failed, periapical surgery or extraction should be considered rather than prolong the ineffected retreatment procedure.

Measurement of thermal expansion characteristic of root canal filling materials: Gutta-percha and Resilon / 대한치과보존학회지

The purpose of this study was to evaluate the thermal expansion characteristics of injectable thermoplasticized gutta-perchas and a Resilon. The materials investigated are Obtura gutta-percha, Diadent gutta-percha, E&Q Gutta-percha Bar and Epiphany (Resilon). The temperature at the heating chamber orifice of an Obtura II syringe and the extruded gutta-percha from the tip of both 23- and 20-gauge needle was determined using a Digital thermometer. A cylindrical ceramic mold was fabricated for thermal expansion test, which was 27 mm long, with an internal bore diameter of 3 mm and an outer diameter of 10 mm. The mold was filled with each experimental material and barrel ends were closed with two ceramic plunger. The samples in ceramic molds were heated in a dilatometer over the temperature range from 25degrees C to 75degrees C. From the change of specimen length as a function of temperature, the coefficients of thermal expansion were determined. There was no statistical difference between four materials in the thermal expansion in the range from 35degrees C to 55degrees C (p > 0.05). However, Obtura Gutta-percha showed smaller thermal expansion than Diadent and Metadent ones from 35degrees C to 75degrees C (p < 0.05). The thermal expansion of Epiphany was similar to those of the other gutta-percha groups.

Effects of Enterococcus faecalis sonicated extracts on IL-2, IL-4 and TGF-beta1 production from human lymphocytes / 대한치과보존학회지

In order to examine the immunoresponse of host cells to Enterococcus faecalis, this in vitro study monitored the production of Interleukin-2 (IL-2), Interleukin-4 (IL-4) and Transforming growth factor-beta1 (TGF-beta1) in human lymphocytes. Lymphocytes were activated with PHA in the presence or abscence of sonicated extracts of E. Faecalis (SEF) and further incubated for 72 hours. The level of each cytokine was measured by ELISA. Data were analyzed with Kruskal-Wallis test and Mann-Whitney U test (P < 0.05). PHA-activated group did exhibit higher level of IL-2 and IL-4 than untreated control group. The levels of expression of both cytokines were significantly decreased following the treatment of high (25 microg/ml) and medium concentration (12.5 microg/ml) of SEF (P <0 .05) than those of PHA activated group. But low concentration (5 microg/ml) of SEF showed the similar level of IL-2 and IL-4 production as those of PHA activated group. TGF-beta1 was unaffected by SEF treatment. These results suggested that E. faecalis may suppress IL-2 and IL-4 production by lymphocytes and this could be one of possible factors why E. faecalis are found frequently in the teeth with failed endodontic treatment.

Evaluation of canal preparation with Ni-Ti rotary files by micro computed tomography / 대한치과보존학회지

The purpose of this study was to compare the effects of preparation with GT files and profiles .04 in shaping of root canals and reconstruct the three-dimensional root canal system using micro computed tomography. 40 canals of the extracted human mandibular molars were used, and randomly distributed into two experimental groups. In group 1, canals were prepared by GT files. In group 2, Profiles .04. were used. Apical preparation size was #30. For each tooth pre and post operative cross-sectional images were obtained by the micro CT at 50 micron intervals. Pre and post operative cross-sectional images of 1, 2, 3, 5, and 8mm from the apex were compared. For each section, canal area and centering ratio were determined. For each tooth pre- and post-operative root canal volume from the furcation to the apex of the roots was calculated by three-dimensional image software. Following results were obtained: 1. At 8mm from the apex, area of dentin removed by GT rotary file was significantly larger than that by Profile .04. And at the other levels there was not a significant difference. 2. There was a trend for GT rotary file to remain more centered in the canals than Profile .04 at all levels. But at 3mm level, there was a statistically significant difference. 3. In root canal volume increments after instrumentation, there was no significant difference between two groups.

Cytotoxicity of resin-based root canal sealer, adseal / 대한치과보존학회지

The properties of ideal root canal sealers include the ability of sealing the total root canal system and no toxic effects to periradicular tissues. Cytotoxicity test using cell culture is a common screening method for evaluation of the biocompatibility of root canal sealers. The purpose of this study was to investigate the cytotoxic effect of newly developed resin-based sealer (Adseal 1, 2, and 3) comparing with those commercial resin-based sealers (AH26 and AH Plus), ZOE-based sealers (Tubliseal EWT, Pulp Canal Sealer EWT) and calcium hydroxide based sealer (Sealapex). An indirect contact test of cytotoxicity by agar diffusion was performed according to the international standard ISO 10993-5. L929 fibroblast cells were incubated at 37degrees C in humidified 5% CO2-containing air atmosphere. The freshly mixed test materials were inserted into glass rings of internal diameter 5 mm and height 5 mm placed on the agar. After the 24 hrs incubation period, the decolorization zones around the test materials were assessed using an inverted microscope with a calibrated screen. A Decolorization Index was determined for each specimen. Adseal 1, 2, and 3 did not exert any cytotoxic effects, whereas AH26, AH Plus, Tubliseal EWT, Pulp Canal Sealer EWT, and Sealapex produced mild cytotoxicity.

Evaluation of Sodium Dichloroisocyanurate as a root canal irrigation solution; Cl- concentration, pH, Cytotoxicity and Antimicrobial effect in vitro / 대한치과보존학회지

The purpose of this study was to evaluate the clinical applications of the Sodium Dichloroisocyanurate effervescent tablet as a routine root canal irrigant by performing several in vitro tests such as Cl- content, cytotoxicity, antimicrobial effect as well as its pH level compared to the equivalent concentration of sodium hypochlorite solution. 1. Sodium Dichloroisocyanurate demonstrated lower level of Cl- concentation than each dilution of sodium hypochlorite solution. Both solution has increased level of Cl- as the concentration of each solution increased. There was no significant change of Cl- concentration in sodium hypochlorite as time goes by. However, Cl- concentration in Sodium Dichloroisocyanurate was increased. 2. The antimicrobial effects of both solutions were increased when their concentrations were increased. One day after dilution, antimicrobial effect of Sodium Dichloroisocyanurate was slightly higher than sodium hypochlorite, however, there was no difference in 1 week dilution solution. One month dilution solution of sodium hypochlorite still retain its activity, but antimicrobial effect of Sodium Dichloroisocyanurate was drastically decreased 1 month after dilution. 3. The cytotoxicity of Sodium Dichloroisocyanurate was rather higher than same concentration of sodium hypochlorite solution until 1 week after dilution. Then in 1 month, cytotoxicity of Sodium Dichloroisocyanurate was decreased than that of 1 week dilution solution, especially 4% Sodium Dichloroisocyanurate solution has almost no toxicity. However, 1% and 2% sodium hypochlorite solution has unchanged moderate degree of cytotoxicity after the dilution. Furthermore, 4% sodium hypochlorite solution showed high level of toxicity. 4. The pH level of Sodium Dichloroisocyanurate showed that the solution was weak acid (pH5). On the other hand, sodium hypochlorite was revealed as a strong alkaline solution (pH12). There was no change in pH following the dilution of each solution. As results, Sodium Dichloroisocyanurate solution fully satisfy the basic requirements as a root canal irrigation solution. However, we strongly recommend to use this solution clinically in low concentration and try to apply into the root canal within 1 week after dilution.

Cytotoxicity and antibacterial property of new resin-based sealer / 대한치과보존학회지

No abstract available.

Leakage of SuperEBA in root-end cavities prepared with 3 new ultrasonic tips;KaVo Isthmus, KaVo T-shape and KiS tip / 대한치과보존학회지

No abstract available.

Sonicated extract of Treponema denticola impairs the lymphocyte proliferation / 대한치과보존학회지

No abstract available.

A Case of Type I membranoproliferative Glomerulonephritis Associated with Cellulitis on Lower Leg / 대한신장학회잡지

Membranoproliferative glomerulonephritis(MPGN) is a morphologic entity and characterized by several pathologic feature. MPGN is classified into a primary (or idiopathic) and secondary forms. We report a case of type I MPGN associated with cellulitis on pathologic feature. MPGN is classified into a primary (or idiopathic) and secondary forms. We report a case of type I MPGN associated with cellulitis on lower leg. He was admitted due to ingrowing nail complicated by surrounding cellulitis and edema. Chraracteristically, hematuria and proteinuria(3.2gm/ day) were noted. We couldn't find any secondary causes', ANA, cryoglobulin, HBs Ag and RA factor were negative. Renal pathologic findings showed double-contoured basement membrane, electron-dense material infiltration and mesangial proliferation. This findings were concordant with type I MPGN and we treated with antibiotics and supportive care. During follow-up, skin lesion, proteinuria and hematuria were resolved and he readmitted in purpose of control renal biopsy, We observed resolution of previous abnormal findings other than mesangial proliferation. This case was considered as type I MPGN associated with cellulitis on lower leg.