Biomedical subjects

Kee-Yeon Kum

Publications and source records attributed to Kee-Yeon Kum.

11 recordsLinked to original sources

PubMed2026

Outcomes and Associated Prognostic Factors for Orthograde Canal Obturation Using Ortho MTA III: A Randomised Prospective Clinical Trial.

AIM: To prospectively compare treatment outcomes for orthograde canal obturation using Ortho MTA III (OMTA) with the continuous wave of compaction (CWC) using gutta-percha (GP) and AH Plus sealer, and to identify associated predictive factors. METHODOLOGY: Informed consent was obtained (110 patients), and single- or two-rooted permanent teeth (n = 120) diagnosed with pulp necrosis (or previously treated) and asymptomatic apical periodontitis or chronic apical abscess (periapical index, PAI ≥ 3) were randomly assigned to two groups (n = 60/group). The canals were prepared to a minimal apical size #40 (ISO) based on their initial file size, disinfected and obturated by either CWC or OMTA using an enhanced disinfection protocol (GP disinfected, new gloves after each intraoperative radiograph and before starting obturation). Clinical and periapical radiographic examinations were conducted by two calibrated, independent endodontists during follow-up periods of at least 12 months. Success rates and associated predictive factors (tooth-, operator- and patient-related) were analysed statistically using binary and multiple logistic regression (p < 0.05). RESULTS: The median recall period was 30 months (14-48 months), and 104 teeth were finally analysed (recall rate: 86.67%). No significant differences in success rate were observed between the groups (p > 0.05) under both loose (OMTA: 88.24%, CWC: 83.02%) and strict criteria (OMTA: 64.71%, CWC: 58.49%). Multivariate analysis revealed that age (OR = 5.735, 95% CI: 1.286-25.577, p = 0.022), periapical lesion size (OR = 6.596, 95% CI: 1.397-31.138, p = 0.017) and PAI score (OR = 2.081, 95% CI: 1.047-4.136, p = 0.036) were significant predictors of treatment failure. CONCLUSIONS: Orthograde obturation of infected canals with Ortho MTA III demonstrated comparable success and treatment outcomes to those filled with GP and sealer by CWC, supporting its potential as a clinically viable alternative for the obturation of infected root canals. TRIAL REGISTRATION: cris.nih.go.kr registration number: KCT00099939.

Humans↗

PubMed2006

Effect of smear layer and chlorhexidine treatment on the adhesion of Enterococcus faecalis to bovine dentin.

The aim of this in vitro study was to determine the effects of a smear layer and chlorhexidine (CHX) treatment on the adhesion of Enterococcus faecalis to bovine dentin. Forty dentin blocks from bovine incisors were prepared and randomly divided into four groups of 10 each. The blocks in group 1 were placed in sterile saline for 5 minutes, while those in group 2 were treated with 17% EDTA for 5 minutes. The blocks in group 3 were placed in 2% CHX for 7 days. The blocks in group 4 were treated with 17% EDTA for 5 minutes, and then placed in 2% CHX for 7 days. All the blocks were immersed in a suspension of E. faecalis for 3 hours. The bacteria adhering to the dentin surface were counted by examination using a scanning electron microscope. The most significant amount of bacteria was retained on the samples from group 1 (p < 0.05) and the smallest amount of bacteria adhered to the samples from group 4. These results suggest that a smear layer enhances the adherence of E. faecalis to the dentin, and CHX is effective in reducing the adherence of microorganisms.

Analysis of Variance↗

PubMed2005

Three-dimensional visualization of a mandibular first molar with three distal roots using computer-aided rapid prototyping.

Nonsurgical endodontic therapy of a right mandibular first molar with 3 distal roots was successfully performed with the aid of magnification. 3D data (DICOM format) of the tooth were obtained from a CT HighSpeed Advantage and a Denta Scan program produced by GE Medical Systems. The CT protocol used for this procedure involved a slit thickness of 1 mm. The 3D digital data obtained were fed into a visualization program (V-works; Cybermed Co) and then exported to the rapid prototyping machine for fabrication of the actual-sized tooth model. The material for the model-making process was starch. The 3D digital visualization and the computer-aided rapid prototyping (CARP) model clearly showed 3 separate distal roots (distobuccal, distolingual, and middle distal). The CARP technique seems to be a useful imaging technology to document unusual root anatomy in clinical dentistry.

Adult↗

PubMed2005

Smear layer production of K3 and ProFile Ni-Ti rotary instruments in curved root canals: a comparative SEM study.

OBJECTIVE: The aim of this scanning electron microscopic study was to compare the quality and amounts of smear layer generated by 2 brands of nickel-titanium rotary instruments during canal preparation in the apical thirds of curved root canals. STUDY DESIGN: Forty mandibular mesial root canals with intact apex and mean curvature between 30 and 35 degrees were selected for this study. The root canals were randomly divided into 2 instrumentation groups of 15 each. Automated preparation was performed with ProFile (Dentsply Maillefer, Ballaigues, Switzerland; n = 15) and K3 (SybronEndo, Orange, Calif; n = 15) instrumentss using a crown-down technique. As a control group, barbed broaches (Mani; Matsutani Seisakusho, Takanezawa-Machi Tochibi-Ken, Japan; n = 10) were used to extirpate the necrotic pulp tissue from the root canals. All root canals were prepared to size #35. Glyde (File Prep, Dentsply Maillefer) was used as lubricant and 1% sodium hypochlorite solution as irrigant. At the conclusion of the experiments, all roots were split longitudinally and the root canal walls were examined at the apical third from 2 different perspectives using a scanning electron microscope. A 4-category scoring system for assessing the smear layer accumulation was used, and the resulting scores were statistically analyzed. RESULTS: Less smear layer was obtained in the K3 group at the selected apical third of curved root canals (P < .05). However, all instruments left a smear layer. The surface texture of the smear layer, in addition to the depth and the frequency of packed materials into the dentinal tubules, varied with instrument type. CONCLUSIONS: This finding may imply that, compared to ProFile, compression of the remaining smear layer is minimized when using the K3 rotary nickel-titanium system.

Dental Alloys↗

PubMed2005

The sustaining effect of three polymers on the release of chlorhexidine from a controlled release drug device for root canal disinfection.

OBJECTIVES: The aim of this in vitro study was to evaluate the suitability of using chitosan, poly (lactide-co-glycolide) (PLGA), and polymethyl methacrylate (PMMA) to control the release of chlorhexidine digluconate (CHX) from a prototype of controlled release drug device for root canal disinfection. STUDY DESIGN: Four different prototypes with different formulations were prepared. Group A (n = 12): the device (absorbent paper point) was loaded with CHX as control. Group B (n = 12): same as group A, but the device was coated with chitosan (Texan MedTech). In Groups C and D, the device was treated in the same way as group A and then coated 3 times with 5% PMMA (Group C, n = 12, Aldrich), or coated 3 times with 3% PLGA (Group D, n = 12, Sigma). The devices were randomly allocated to experimental groups of 12 each. All the prototypes of controlled release drug device were soaked in 3 mL distilled water. The concentrations of CHX were determined using a UV spectrophotometer. The surface characteristics of each prototype were observed using a scanning electron microscope. RESULTS: The result showed that release rate of CHX was the greatest in the noncoated group, followed by the chitosan-coated group, the PLGA-coated group, and the PMMA-coated group (P < 0.05). Pores were observed on the surface of the prototypes that were coated with PLGA and PMMA. When the pore size was smaller, the release rate was lower. CONCLUSION: These data indicate that polymer coating can control the release rate of CHX from the prototypes of controlled release drug device.

Analysis of Variance↗

PubMed2005

Evaluation of the prognosis and causes of failure in 182 cases of autogenous tooth transplantation.

OBJECTIVES: Autotransplantation is a viable option for treating missing teeth when a donor tooth is available. The aim of this study was to evaluate the prognosis in addition to the causes of failure in 182 autotransplanted teeth. STUDY DESIGN: A total of 182 cases of autotransplantation were analyzed. All the transplants were performed according to a computer-aided rapid prototyping technique with an average extraoral time of 7.58 minutes. These cases were followed for 2 to 60 months after surgery. The prognosis was divided into 4 groups, complete healing, incomplete healing, uncertain healing, and failure. The initial stability, root resorption, and ankylosis were also analyzed. RESULTS: Most transplanted teeth showed complete healing between postoperative 2 months and 8 months. The transplanted teeth with a good initial stability showed better initial healing than those with a poor initial stability. The average extraoral time was 7.58 min (range: immediately after extraction up to 25 min). There was no relationship (P > .05) between the extraoral time and either root resorption (4 cases, 2.4%) or ankylosis (18 cases, 10.7%) within this experimental time period. Nine cases (4.5%) failed. CONCLUSION: This study showed a 4.5% failure rate during the short to intermediate observation period. Autotransplantation is a very useful method for replacing missing teeth, provided that the extraoral time and other factors are well controlled.

Adolescent↗

PubMed2005

Apical anatomy in mesial and mesiobuccal roots of permanent first molars.

The purpose of this in vitro study was to investigate the canal configuration types, and the prevalence and location of anatomical variations in the mesiobuccal (MB) and mesial roots of permanent maxillary and mandibular first molars after instrumentation. The number and the type of canals were determined before instrumentation using conventional methods. All root canals from the 47 MB roots and 42 mesial roots were then instrumented to size #30 with ProFile .04 taper rotary instruments in a crown-down method and then filled with a single gutta-percha cone and sealer. Transverse 1 mm-thick cross-sections at 2, 3, 4, and 5 mm from the apex were obtained, stained and examined using a stereomicroscope. The canal configuration types and the prevalence and location of isthmi and accessory canals in roots with two canals were evaluated. The prevalence of two canals was 80.8% in the maxillary MB roots and 95.2% in the mandibular mesial roots. There were six types of canal configurations in the instrumented root apices. The prevalence of anatomical variations was highest at the apical 4 mm level, and was more frequent in mandibular first molars, and in roots with Weine type III canal. chi test showed that the prevalence of the anatomical variations was statistically higher in the maxillary MB roots with Weine type III canals than in those with Weine type II canals (p < 0.05). Different canal configurations were often found at different levels in the same root. The results indicate that anatomical variations persist following instrumentation of roots with two canals in first molars. These anatomical variations should be considered during surgical or nonsurgical endodontic procedures of the permanent first molars.

Chi-Square Distribution↗

PubMed2004

Effects of removing residual peroxide and other oxygen radicals on the shear bond strength and failure modes at resin-tooth interface after tooth bleaching.

PURPOSE: To investigate the effects of removing residual peroxide on the bond strength and the failure mode at the interface of resin-based composite and enamel after tooth bleaching. METHODS: Standard-sized light-cured resin cylinders were formed on, and bonded to the flattened bleached enamel surfaces of 60 human canine and premolars which had previously been subjected to three different surface treatments for 3 minutes: (1) catalase; (2) 70% ethanol; (3) sprayed water. For each experimental group (n=12), non-bleached teeth and 2-week post-bleached teeth without any surface treatment were used for negative and positive control respectively. Specimens were thermocycled, tested in shear until failure, and the results statistically analyzed. All fractured specimens were examined by scanning electron microscopy. RESULTS: Pretreatment of bleached surface with the catalase and the ethanol prior to bonding significantly improved the composite-enamel bond strength compared to the water-sprayed group (P< 0.05). However, the bond strength level of the ethanol group did not return to the level recorded for the non-bleached negative control group. Scanning electron microscopic examination of randomly selected, fractured specimens indicated that the peroxide-induced reduction in bond strength was related to alterations in both attachment-surface area at the resin-enamel interface and resin quality.

Analysis of Variance↗

PubMed2003

Smear layer production by 3 rotary reamers with different cutting blade designs in straight root canals: a scanning electron microscopic study.

OBJECTIVES: The design of the cutting blade of rotary instruments may affect the outcome of root canal instrumentation in terms of cleanliness. The aim of this scanning electron microscopic study was to compare the quality and amount of smear layer generated in the apical third of straight root canals by 2 rotary nickel-titanium reamers and 1 rotary steel reamer with different cutting blade designs. STUDY DESIGN: Seventy intact, single-rooted human mandibular premolars with straight, fully developed roots were selected for this study. Before instrumentation, the cervical portion of all teeth was removed by using a microtome (Isomet), leaving 13-mm-long roots. Automated preparation was performed with ProFile (n = 20) and Hero 642 (n = 20) reamers by using the crown-down technique and with a stainless steel engine reamer (Mani; n = 20) by using a reaming motion. All root canals were instrumented to No. 40. A control group (pulp extirpation with barbed broaches; n = 10) was also included. Irrigation with 3 mL of a 1% sodium hypochlorite (NaOCl) solution was performed after each instrumentation. After the instrumentation, each root was split longitudinally, and a scanning electron microscope was used to examine the selected areas of the canal walls at the apical third from 2 different perspectives. A 4-category scoring system for smear layer was used, and the resulting scores were statistically analyzed. RESULTS: The least smear layer remained in the Hero 642 group at the selected apical third of straight root canals (P < .05). However, all instruments left a smear layer. The surface texture of the smear layer, in addition to the depth and the frequency of packed materials into the dentinal tubules, varied with instrument type. CONCLUSION: These data revealed that the design of the cutting blade of rotary instruments can affect root canal cleanliness in straight root canals. This information may be useful in the selection of nickel-titanium rotary reamers.

Dental Alloys↗

PubMed2003

The inhibitory effect of alendronate and taurine on osteoclast differentiation mediated by Porphyromonas gingivalis sonicates in vitro.

The objective of this study was to investigate the ability of alendronate and taurine in inhibiting in vitro osteoclast differentiation induced by bacteria. Whole cell sonicates of Porphyromonas gingivalis were used as an osteoclast-stimulating factor in a mouse coculture system and differentiated osteoclasts were confirmed by tartrate-resistant acid phosphatase (TRAP) staining. Alendronate at the concentrations of 10(-7) M, 10(-6) M, and 10(-5) M and taurine at the concentrations of 4 mM, 8 mM, and 12 mM were used. The cytotoxic effects of alendronate and taurine were examined using methylthiazole-tetrazolium bromide (MTT) assay. The amounts of interleukin-6 (IL-6) in culture supernatants were also measured using ELISA. The sonicates of P. gingivalis at the concentration of 0.01-0.1 microg/ml significantly stimulated the formation of osteoclasts (p < 0.05). Alendronate (10(-5) M) and taurine (12 mM) significantly suppressed the sonicate-stimulated osteoclast formation. In MTT assay, no cytotoxic effects were evident in all concentrations of alendronate and taurine. Alendronate and taurine did not affect the amount of IL-6 induced by P. gingivalis sonicates. These data indicate that alendronate and taurine have inhibitory effects on bacteria-stimulated osteoclast formation in vitro and that this inhibitory mechanism is not related to the blocking of IL-6 production.

Alendronate↗

PubMed2003

Effect of dexamethasone on root resorption after delayed replantation of rat tooth.

The purpose of this study was to evaluate the effect of dexamethasone after delayed tooth replantation with specific regard to root resorption and ankylosis. In addition, the study was planned to elucidate further the usefulness of the model. Fifty-two maxillary first molar teeth were extracted from 26 Sprague-Dawley white female rats fed 0.4% beta-aminoproprionitrile for 3 days to facilitate the extraction. After extraction, the mesiobuccal root canals were endodontically treated under a microscope to prevent subsequent inflammatory resorption of pulpal origin and were assigned to three groups. Teeth in group 1, the dexamethasone group (n = 22), were demineralized in citric acid (1 min), washed, soaked in 1000 nM dexamethasone solution (3 min), air-dried, and replanted in the original sockets. Total extraoral treatment time for each tooth was controlled to 30 min. Teeth in group 2, the dried-only group (n = 22), were air-dried for 30 min after obturation without any surface treatment and replanted. Teeth in group 3, the immediate group (n = 8), were extracted, not root-filled and replanted immediately into their sockets. All experimental animals were killed at 3 weeks after replantation and evaluated histologically. Forty-three of the 52 teeth were available for histological interpretation. They consisted of six immediate, 18 dried-only, and 19 dexamethasone-treated teeth. The degree of progressive root resorption was significantly less in the dexamethasone-treated group than in the dried-only group (p < 0.05). The dexamethasone-treated group exhibited significantly more bone ankylosis than the dried-only group (p < 0.05). These results indicate that the topical use of dexamethasone may be of value in reducing the degree or rate of progressive root resorption secondary to traumatic avulsion and that the rat is a reasonable model for tooth replantation.

Administration, Topical↗