• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.495-500
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• 2004

Dens invaginatus is a malformation of tooth resulting from an infolding of the enamel epithelium during tooth development. This malformation shows a broad spectrum of morphologic variations. This invagination frequently allows the entry of irritants and microorganism, which usually lead to necrosis of the adjacent pulp tissue and then to periapical or periodontal abscess. Root canal treatment of such tooth is often difficult because of the un usual form and complicated pulpal space. This article reports 2 cases of dens invaginatus in maxillary lateral incisors. The first case was successfully treated with $Ca(OH)_2$. In the second case, involved tooth was extracted and this extracted tooth was observed using the micro-computed tomography.

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.246-256
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• 2010

The purpose of this study was to evaluate a rotational stability of endodontic electronic motors by comparing the changes of rotational speed, depending on the number of usages and with/without static load. Twelve new endodontic electronic motors were used in this study. Non contact type digital tachometer was used for measuring the rotational speed of handpiece. True RMS Multimeter was used for measuring the voltages and the electric currents. All measurements were recorded every 10 seconds during 10 minutes and repeated 9 times. Five repetition was done per each electronic motor. To statistical analysis, student t-test, repeated measures and Scheffe's post-hoc tests were performed. In the same motor group, there was no significant difference in all measurements. In all groups, there was no significant difference in the amount of rotational speed changes depending on the number of usages and with/without static load. In the limitation of this study, the results showed that all kinds of endodontic electronic motors in this study had an established rotational stability. Therefore they could be safely used in root canal treatment with a reliable maintenance of rotational speed, regardless of the number of usages and with/without load.

• Restorative Dentistry and Endodontics
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• v.30 no.3
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• pp.215-220
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• 2005

It is common for clinicians to encounter endodontically tl·treated teeth that contain posts within their roots. If endodontic treatment is failed, these posts must be removed to facilitate successful nonsurgical retreatment. There have been many techniques such as ultrasonic instrument, Ruddle post removal system, Eggler post remover and Masserann kit developed to facilitate removal of posts from the root canal space. But these methods may be disadvantageous because long length of time required for post removal and fracture of post or teeth. In now days new post removal technique using ATD automatic bridge remover was introduced. Advantages of this method are simple and short time consuming compare to others. This article served as a successful case report of post removal using ATD automatic bridge remover.

• Restorative Dentistry and Endodontics
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• v.28 no.2
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• pp.178-183
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• 2003

The purpose of this study was to investigate the frequency of 7 putative pathogens in endodontic infections. The specimens were collected from infected pulpal tissue of patients who were referred for root canal treatment to the department of conservative dentistry, Chosun University Samples were collected aseptically using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing 500 ml of 1 X PBS. DNAs were extracted from the samples by direct DNA extraction method using lysis buffer (0.5% EDTA, 1% Triton X-100). Identification of 7 putative pathogens was performed by PCR based on 16S rDNA. The target species were as follows : Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Bacteroides forsythus, Actinobacillus actinomycetemcomitans, and Treponema denticola. Our data revealed that the prevalence of P. endodontalis was found in 88.6% (39/54), P. ginivalis 52.3% (23/44), P. nigrescens 18.2% (8/44), P intermedia 15.9% (7/44) B. forsythus 18.2% (8/44), A. actinomycetemcomitans 3.3% (1/44), T. denticola 25% (l1/44) of the samples. The high prevalence of P. endodontalis and P. ginivalis suggests that they may play an important role in the etiology of endodontic infections.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.1
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• pp.131-138
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• 2006

A mixture of metronidazole, ciprofloxacin and minocycline(3Mix) in distilled water or in a root canal sealer were used to disinfect the infected endodontic and periapical lesions. It has been well acknowledged in recent literature that minocycline, a semisynthetic tetracycline derivative, causes discolorations in adult teeth and various other collagenous tissues. In these cases, pulp treatments were finished successfully using a combination of antibiotics but severe discolorations of the teeth were observed. Discolored non-vital posterior tooth was treated using the prosthodontic procedure. And anterior tooth was successfully treated using the walking bleach technique. Bleaching was performed by temporarily placing a mixture of sodium perborate and distilled water into the pulp chamber. There were significant esthetic improvement.

• Restorative Dentistry and Endodontics
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• v.42 no.2
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• pp.111-117
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• 2017

Objectives: Periapical lesions, including periapical cyst (PC), periapical granuloma (PG), and periapical abscess (PA), are frequently affected by chemical/physical damage during root canal treatment or severe bacterial infection, and thus, the differential diagnosis of periapical lesions may be difficult due to the presence of severe inflammatory reaction. The aim of this study was to make differential diagnosis among PC, PG, and PA under polarizing microscope. Materials and Methods: The collagen birefringence patterns of 319 cases of PC (n = 122), PG (n = 158), and PA (n = 39) obtained using a polarizing microscope were compared. In addition, 6 cases of periodontal fibroma (PF) were used as positive controls. Results: Collagen birefringence was condensed with a thick, linear band-like pattern in PC, but was short and irregularly scattered in PG, and scarce or absent in PA. PF showed intense collagen birefringence with a short, palisading pattern but no continuous band-like pattern. The linear band-like birefringence in PC was ascribed to pre-existing expansile tensile stress of the cyst wall. Conclusions: In this study all PCs (n = 122) were distinguishable from PGs and PAs by their characteristic birefringence, despite the absence of lining epithelium (n = 20). Therefore, the authors suggest that the presence of linear band-like collagen birefringence of the cyst wall aids the diagnostic differentiation of PC from PG and PA.

• Restorative Dentistry and Endodontics
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• v.24 no.2
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• pp.286-298
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• 1999

The endodontic-periodontic combined lesions have been difficult to get correct diagnosis and predictable treatment. This study was to make the experimental endodontic-periodontic combined defects in dogs for the study of the periodontal regeneration and to evaluate the efficacy of the enamel matrix protein and e-PTFE membrane in the experimental endodontic-periodontic combined defects. 5 mongrel dogs were used. The pulp chambers were opened and the plaque was inserted into the chambers to induce the periapical lesions on the mandibular second, third and fourth premolars of the dogs. 1 month later, the root canal treatments were done with gutta perch a and ZOE sealer. On the day of surgery, the periapical defects were standardized by trephine bur. The buccal dehiscence defects were made by the dental bur and bone chisels. The apicoectomy with retrofilling was done. The prepared roots were randomly selected for test and control groups. In the experimental groups, the enamel matrix derivative and e-PTFE membrane were used. Nothing was placed on the control group. Fluroscent labelling was used to evaluate the bone formation. After 4 and 12 weeks, the dogs were sacrificed and undecalcified sections were prepared and stained with toluidine blue. Those histologic sections were examined by fluorescent microscopy and light microscopy. The results were as follows. 1. In the control group, new bone was formed in the periapical defects and scarcely in the buccal dehiscence defects. New cementum was not detected at 4 and 12 weeks. 2. In the experimental groups, new bone, new cementum and periodontal ligament were found in the periapical and buccal dehiscence defects. The relative amount and the quality of the new bone, new cementum and periodontal ligament tissue that had formed on the experimental groups were superior to those of the control group. 3. The current observation implicated that e-PTFE membrane and enamel matrix protein could be the effective tools for the guided tissue regeneration of the endo-perio combined defects.

• Restorative Dentistry and Endodontics
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• v.46 no.1
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• pp.6.1-6.10
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• 2021

Objectives: The aim of this study was to evaluate the corrosion resistance of heat-treated (Reciproc and WaveOne) and non-heat-treated (ProTaper and Mtwo) superelastic nickel-titanium endodontic files when immersed in a 5.25% sodium hypochlorite solution. Materials and Methods: Anodic polarization curves were obtained with potential sweeps that began at the open circuit potential or corrosion potential (E_corr). The pitting potential (E_pit) was identified on the anodic polarization curve as the potential at which a sudden increase in current was observed. The micromorphology of the 28 tested files was analyzed before and after the electrochemical assay using scanning electron microscope (SEM). The data were analyzed using 1-way analysis of variance with the post hoc Bonferroni test (for E_corr) and the Student t-test for independent samples (for E_pit). Results: The mean E_corr values were 0.506 V for ProTaper, 0.348 V for Mtwo, 0.542 V for Reciproc, and 0.321 V for WaveOne files. Only WaveOne and Protaper files exhibited pitting corrosion, with E_pit values of 0.879 V and 0.904 V, respectively. On the SEM images of the ProTaper and WaveOne files, cavities suggestive of pitting corrosion were detected. Conclusions: Signs of corrosion were observed in both heat-treated and non-heat-treated files. Of the evaluated files, WaveOne (a heat-treated file) and ProTaper (a non-heat-treated file) exhibited the lowest corrosion resistance.

• Restorative Dentistry and Endodontics
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• v.47 no.3
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• pp.27.1-27.14
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• 2022

Objectives: This systematic review and meta-analysis aimed to assess the association of cigarette smoking with the prevalence of post-endodontic apical periodontitis in humans. Materials and Methods: We searched through PubMed/Medline, Web of Science, and Scopus from inception to December 2020. Risk of bias was performed by using the Newcastle-Ottawa Scale for cross-sectional, cohort, and case-control studies. We performed the statistical analysis in Review Manager 5.3 (RevMan 5.3). Results: 6 studies met the inclusion criteria for qualitative and quantitative synthesis. Statistical analysis of these studies suggests that there were no differences in the prevalence of post endodontic apical periodontitis (AP) when comparing non-smokers vs smoker subjects regarding patients (odds ratio [OR], 0.68; 95% confidence interval [CI], 0.31-1.49; I2 = 58%) and teeth (OR, 1.71; 95% CI, 0.99-2.93; I2 = 72%). Conclusions: Our findings suggest that there was no association between cigarette smoking and post-endodontic apical periodontitis, as we did not find statistical differences in the prevalence of post-endodontic AP when comparing non-smokers vs smoker subjects. Therefore, smoking should not be considered a risk factor associated with endodontic failure.

• Restorative Dentistry and Endodontics
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• v.35 no.5
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• pp.335-343
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• 2010

Objectives: To compared the effect of different levels of moisture of root canal on the sealing ability after filling with four different types of sealer. Materials and Methods: Single-rooted teeth (n = 90) instrumented to and apical size of 0.06 / 45 were randomly assigned to 12 experimental groups (n = 7 per group), positive/negative control groups (n = 3 per group). The teeth of the experimental groups (a. DRY; b. PAPER POINT DRY; c. WET) were obturated with sealer (Group 1-3: Sealapex; Group 4-6: AH plus; Group 7-9: Tubuli-seal; Group 10-12: EndoRez) and warm vertical compaction method. After 7 days in $37^{\circ}C$, 100% humidity, the coronal-to-apical microleakage was evaluated quantitatively using a glucose leakage model. The leaked glucose concentration was measured with spectrophotometer at 1, 3, 7, 14, 21, and 30 days. Data were recorded ad mmol/L and statistically analysed with the two-way ANOVA and Duncan test (p = 0.05). Results: Throughout the experimental period Tubuli-seal/WET (Group 9) showed the highest mean cumulative glucose penetration (178.75 mmol/L), whereas AH plus/DRY (Group 4) had the least (20.78 mmol/L). Conclusions: The results of this study demonstrated that the moisture condition of root canals at the time of obturation and the type of sealer that was used had a significant effect on leakage and sealing ability. Thus drying procedure according to sealer types is a critical step and should not be missed in endodontic treatment.