• Imaging Science in Dentistry
• /
• v.35 no.2
• /
• pp.91-96
• /
• 2005

Purpose : To investigate the change of bone healing process after endodontic treatment of the tooth with an apical lesion by fractal analysis. Materials and Methods Radiographic images of 35 teeth from 33 patients taken on first diagnosis, 6 months, and 1 year after endodontic treatment were selected. Radiographic images were taken by JUPITER Computerized Dental X-ray $System^{(R)}$. Fractal dimensions were calculated three times at each area by Scion Image $PC^{(R)}$ program. Rectangular region of interest $(30\times30)$ were selected at apical lesion and normal apex of each image. Results : The fractal dimension at apical lesion of first diagnosis $(L_0)$ is $0.940{\pm}0.361$ and that of normal area $(N_0)$ is $1.186{\pm}0.727(p<0.05)$. Fractal dimension at apical lesion of 6 months after endodontic treatment $(L_1)$ is $1.076{\pm}0.069$ and that of normal area $ (N_1)$ is $1.192{\pm}0.055(p<0.05)$. Fractal dimension at apical lesion of 1 year after endodontic treatment $(L_2)$ is $1.163{\pm}0.074$ and that of normal area $(N_2)$ is $1.225{\pm}0.079(p<0.05)$. After endodontic treatment, the fractal dimensions at each apical lesions depending on time showed statistically significant difference. And there are statistically significant different between normal area and apical lesion on first diagnosis, 6 months after, 1 year after. But the differences were grow smaller as time flows. Conclusion : The evaluation of the prognosis after the endodontic treatment of the apical lesion was estimated by bone regeneration in apical region. Fractal analysis was attempted to overcome the limit of subjective reading, and as a result the change of the bone during the healing process was able to be detected objectively and quantitatively.

• Restorative Dentistry and Endodontics
• /
• v.35 no.6
• /
• pp.436-444
• /
• 2010

Objectives: This study aimed to assess prospectively the clinical outcome of nonsurgical endodontic treatment and identify patient- and tooth-related factors, rather than treatment-related factors, that were the best predictors of this outcome. Materials and Methods: The inception cohort comprised 441 teeth (320 patients) and 175 teeth (123 patients) were followed up for 1-2 years. Age, gender, presence of medical disease, number of canals, previous endodontic treatment, presence of sensitivity and pain, pulp vitality, swelling or sinus tract of pulpal origin on the gingiva, periapical radiolucency and tendency of unilateral bite on the affected tooth were recorded at treatment start. Results: The outcome was classified on the basis of periapical radiolucency as healed or non healed. The overall healed rate in these cases, including nonsurgical retreatment, was 81.1%. Four tooth-related factors had a negative impact in the bivariate analysis: previous endodontic treatment, necrotic pulp, preoperative gingival swelling or sinus tract of pulpal origin, and preoperative periapical radiolucency. Stepwise logistic regression analysis including patient-, tooth-related factors and level of the root canal filling as a treatment-related factor showed that preoperative gingival lesion (odds ratio [OR]: 4.4; p = 0.005), preoperative periapical radiolucency (OR: 3.6; p = 0.011), and $\leq$ 1-2 mm under root filling length (OR: 9.6; p = 0.012) were significant predictors of failure. Conclusions: A preoperative gingival lesion of pulpal origin can influence the outcome of nonsurgical endodontic treatment in addition to preoperative periapical radiolucency.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.35 no.3
• /
• pp.143-152
• /
• 2019

Purpose: The aim of this study is to investigate the characteristics of patients and teeth referred to a university dental hospital for endodontic problem. Materials and Methods: From January, 2017 to December, 2018, patients who were referred to a university dental hospital for endodontic problem were collected from clinical records. A total of 1171 patient records were analyzed. The status of the referred teeth was divided into three groups according to whether they were treated endodontically based on radiographs and clinical records at the time of referred visit. Results: 69.9% of the referred teeth were maxillary and mandibular first and second molars. The average time from referral to actual visit is 9.03 days and 65.6% of the case referred with referring letter. The most primary reasons of referral were persistent clinical symptom (pain, swelling, and sinus tract) (37.9%), diagnosis difficulty (16.7%), blockage of canal space (13.8%) and difficult tooth anatomy (11.4%). In the case of referral before endodontic treatment, the most primary reason of referral was failure to make a proper diagnosis. If the teeth were referred in the middle of endodontic treatment, the most primary reason of referral was persistent clinical symptom and blockage of canal space. In the case of referral after root canal filling, the most primary reason of referral was persistent clinical symptom. Conclusion: In the case of molars, the rate of persistent clinical symptom and blockage of canal space were the most primary reason of referral, and the rate of apical surgery and management of trauma was high in the case of anterior teeth.

• Proceedings of the KACD Conference
• /
• 2001.11a
• /
• pp.582.2-582
• /
• 2001

Black-pigmented bacteria anaerobes have been implicated in the endodontic infections. This group of microorganisms includes Porphyromonas endodontalis, Porphyromonas gingivalis, prevotella intermedia, and Prevotella nigrescens. The organisms display a wide variety of virulence factors that may be pertinent to acute endodontic infections.(omitted)

• Proceedings of the KACD Conference
• /
• 2001.11a
• /
• pp.574.1-574
• /
• 2001

Maxillary first molar, the "6-year molar", is the tooth largest in volume and most complex in root and root canal anatomy. Therefore, maxillary first molar is possibly the most treated, least understood. It is the posterior tooth with the highest endodontic failure rate and unquestionably one of the most important teeth. The earliest permanent posterior tooth to erupt, the mandibular first molar seems to be the most frequently in need of endodontic treatment.(omitted)

• The Journal of the Korean dental association
• /
• v.51 no.10
• /
• pp.556-564
• /
• 2013

Modern endodontics has essentially changed following the introduction of the dental microscope since 1990's. One of main advantage of using dental microscope in nonsurgical endodontic treatment is enhancing clinician's ability and quality of treatment through illumination and magnification. Scopes of dental microscope in nonsurgical endodontics are finding a missed or additional root canal and a tooth crack, management of procedural errors, and others. These improvements in technology will result in greater confidence in treatment and better success in clinical practice.

• Proceedings of the KACD Conference
• /
• 2003.11a
• /
• pp.580-580
• /
• 2003

I. Objectives This study investigated the quantity of debris which was extruded apically after canal instrumentation using different types of enlarging instrument in endodontic resin models. II. Materials and Methods Five groups of 9 endodontic resin model were instrumented using each different technique：hand instrumentation without early coronal flaring, hand instrumentation after early coronal flaring, and three nickel-titanium engine-driven instrumentations(Hero 642, Protaper, K3) after early coronal flaring.(omitted)

• Proceedings of the KACD Conference
• /
• 2003.11a
• /
• pp.606-606
• /
• 2003

There have been many studies that have evaluated success and failure of endodontic treatment (Nair, Sjogren), but there is remarkably limited information concerning the specific microorganisms that are involved in the teeth with treatment failure. Microorganisms that survive root canal treatment to cause a persistent infection must possess specific characteristics to avoid the host defense. These can be broadly classified as; 1. Sequestration：A physical barrier between the microbe and the host. 2. Cellular evasion：Microorganisms avoid leukocyte dependent antibacterial mechanisms. 3. Humoral evasion：Extracellular bacteria avoid the hosts antibodies and complement.(omitted)

• International Journal of Oral Biology
• /
• v.38 no.4
• /
• pp.141-147
• /
• 2013

It has been established that berberine has strong antimicrobial effects. Little is known however regarding the antimicrobial activity of berberine against endodontic pathogenic bacteria or its cytotoxicity in human oral tissue cells. The antibacterial properties of berberine were tested against 5 strains of Enterococcus faecalis and type strains of Aggregatibacter actinomycetemcomitans, Prevotella nigrescens, Prevotella intermedia, and Tannerella forsythia, which are involved in endodontic infections. Antimicrobial activity was evaluated through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) measurements. The viability of normal human gingival fibroblast (NHGF) cells after exposure to berberine was measured using a methyl thiazolyl tetrazolium (MTT) assay. The data showed that berberine has antimicrobial effects against A. actinomycetemcomitans with an MIC and MBC of $12.5{\mu}g/ml$ and $25{\mu}g/ml$, respectively. In the cytotoxicity studies, cell viability was maintained at 66.1% following exposure to $31.3{\mu}g/ml$ berberine. Overall, these findings suggest that berberine has antimicrobial activity against the tested bacteria. Nevertheless, lower concentrations in combination with other reagents will need to be tested before these in vitro results can be translated to clinical use.

• Restorative Dentistry and Endodontics
• /
• v.44 no.4
• /
• pp.44.1-44.11
• /
• 2019

Objectives: To compare the flexural cyclic fatigue resistance and the length of the fractured segments (FLs) of recently introduced M-Pro rotary files with that of RaCe rotary files in curved canals and to evaluate the fracture surface by scanning electron microscopy (SEM). Materials and Methods: Thirty-six endodontic files with the same tip size and taper (size 25, 0.06 taper) were used. The samples were classified into 2 groups (n = 18): the M-Pro group (M-Pro IMD) and the RaCe group (FKG). A custom-made simulated canal model was fabricated to evaluate the total number of cycles to failure and the FL. SEM was used to examine the fracture surfaces of the fragmented segments. The data were statistically analyzed and comparisons between the 2 groups for normally distributed numerical variables were carried out using the independent Student's t-test. A p value less than 0.05 was considered to indicate statistical significance. Results: The M-Pro group showed significantly higher resistance to flexural cyclic fatigue than the RaCe group (p < 0.05), but there was no significant difference in the FLs between the 2 groups (p ≥ 0.05). Conclusions: Thermal treatment of nickel-titanium instruments can improve the flexural cyclic fatigue resistance of rotary endodontic files, and the M-Pro rotary system seems to be a promising rotary endodontic file.