• Journal of the korean academy of Pediatric Dentistry
• /
• v.43 no.4
• /
• pp.419-426
• /
• 2016

For this research 20 supernumerary teeth impacted in the maxillary anterior have been extracted and pulp cells have been collected from them. From the collected pulp cells, total of 17 (10 males, 7 females) have been selected as subjects. From this research, the run-time of successive culture of the cell from tooth number pulp tissue was $2.91{\pm}0.29$ days. From the gathering of cells from the initial pulp tissue until gaining 80% confluency took $4.53{\pm}0.94$ which was the longest. The following successive cultures took $2.73{\pm}0.32$ days. Average runtime for female was $2.81{\pm}0.27$ days whereas male had average runtime of $2.98{\pm}0.29$ days. Average run-time for inversion was $2.94{\pm}0.30$ days and for normal location, $2.80{\pm}0.20$ days. Average runtime was $2.92{\pm}0.31$ days and other forms took $2.88{\pm}0.22$ days. In the future, follow up research would be needed to evaluate the efficiency of the cells collected from the initial passage and the latter passage as stem-cells and taking into consideration the less than 3 days'time for the subculture, it could be concluded that the research efficiency and fast cultivation would be sufficiently effective.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.36 no.2
• /
• pp.305-309
• /
• 2009

Dens evaginatus is a dental anomaly most commonly seen in premolar teeth in which a tubercle or protuberance projects from either the center of the occlusal surface or the buccal triangular ridge. These tubercles are easily fractured from mastication as the tooth erupts and frequently leads to pulp necrosis as a common complication. To prevent these sequelae, prophylactic treatment soon after the tooth starts erupting is essential. These preventive treatments include, selective grinding and protection of the tubercle by pit and fissure sealant. When the tooth does shows signs of pulp necrosis and apical periodontitis, endodontic procedures are needed. Apexification and apexogenesis are usually the treatment of choice for the affected teeth which have immature apices. Apexogenesis is a vital pulp therapy procedure performed to encourage continued physiological development and formation of the root end. It involves removal of the inflamed pulp and the placement of calcium hydroxide on the remaining healthy pulp tissue. This case report describes an atypical apexogenesis of a mandibular premolar which showed to be a dens evaginatus. The tooth which was treated with calcium hydroxide shows good results and is planned for permanent root canal filling.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.47 no.2
• /
• pp.148-156
• /
• 2020

The purpose of this study was to compare the success rates of two pulp capping materials, Biodentine™ and RetroMTA^®, used for partial pulpotomy in permanent molars after carious exposures and to compare the final restorative outcome of using composite resin to that of using a stainless steel crown. We studied children who were diagnosed with dental caries of permanent molars and underwent partial pulpotomy. The patients were followed up for more than 1 year. Clinical and radiographic evaluation were used to evaluate the success of each treatment. Fisher's exact test was used to compare the outcomes of two groups. For pulp capping agents, the success rate of using RetroMTA^® was lower than that of using Biodentine™(p < 0.05). Final restoration with composite resin was less successful than restoration with an stainless steel crown(p < 0.05). In combination of pulp capping agents and final restoration material, RetroMTA^®-composite resin shows the lowest success rate(p < 0.05).

• Restorative Dentistry and Endodontics
• /
• v.34 no.2
• /
• pp.120-129
• /
• 2009

The purpose of this study was to investigate the pulpal response to direct pulp capping with dentin sialoprotein (DSP) -derived synthetic peptide in teeth of dogs, and to compare its efficacy to capping substances $Ca(OH)_2$ and white mineral trioxide aggregate (WMTA). A total of 72 teeth of 6 healthy male beagle dogs were used. The mechanically exposed pulps were capped with one of the following: (1) DSP-derived synthetic peptide (PEP group): (2) $Ca(OH)_2$ (CH group): (3) a mixture paste of peptide and $Ca(OH)_2$ (PEP+CH group): or (4) white MTA (WMTA group). The access cavity was restored with a reinforced glass ionomer cement. Two dogs were sacrificed at each pre-determined intervals (2 weeks, 1 month, and 3 months). After the specimens were prepared for standard histological processing, sections were stained with hematoxylin and eosin. Under a light microscope, inflammatory response and hard tissue formation were evaluated in a blind manner by 2 observers. In the PEP group, only 3 of 17 specimens showed hard tissue formation, indication that the DSP-derived synthetic peptide did not induce proper healing of the pulp. Compared with the CH group, the PEP group demonstrated an increased inflammatory response and poor hard tissue formation. The CH and WMTA groups showed similar results for direct pulp capping in mechanically exposed teeth of dogs.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.51 no.2
• /
• pp.149-164
• /
• 2024

This study compared the solubility, water absorption, dimensional stability, release of various ions (hydroxyl, calcium, sulfur, strontium, and silicon), and cytotoxicity of light-cured resin-modified pulp-capping materials. Resin-modified calcium hydroxide (Ultra-blend^TM plus, UBP), light-cured resin-modified calcium silicate (TheraCal LC^TM, TLC), and dual-cure resin-modified calcium silicate (TheraCal PT^TM, TPT) were used. Each material was polymerized; solubility, 24-hour water absorption, and 30- day dimensional stability experiments were conducted to test its physical properties. Solubility was assessed according to the ISO 6876 standard, and 24 hours of water absorption, 30 days of dimensional stability were assessed by referring to the previous protocol respectively. Eluates at 3 and 24 hours and on 7, 14, and 28 days were analyzed according to the ISO 10993-12 standard. And the pH, Ion-releasing ability, cell proliferation rate, and cell viability were assessed using the eluates to evaluate biochemical characteristics. pH was measured with a pH meter and Ion-releasing ability was assessed using inductively coupled plasma atomic emission spectrometry (ICP-AES). Cell proliferation rate and cell viability were assessed using human dental pulp cells (hDPCs). The former was assessed by an absorbance assay using the CCK-8 solution, and the latter was assessed by Live and Dead staining. TPT exhibited lower solubility and water absorption than TLC. UBP and TPT demonstrated higher stability than TLC. The release of sulfur, strontium, calcium, and hydroxyl ions was higher for TLC and TPT than for UBP. The 28-day release of hydroxyl and silicon ions was similar for TLC and TPT. TLC alone exhibited a lower cell proliferation rate compared to the control group at a dilution ratio of 1 : 2 in cell proliferation and dead cells from Live and Dead assay evaluation. Thus, when using light-cure resin-modified pulp-capping materials, calcium silicate-based materials can be considered alternatives to calcium hydroxide-based materials. Moreover, when comparing physical and biochemical properties, TPT could be prioritized over TLC as the first choice.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.33 no.2
• /
• pp.154-162
• /
• 2017

Tooth wear, one of the physiological changes in the elderly patient's mouth, generally does not require treatment, but requires prosthodontic restoration when occlusal disharmony, poor masticatory function, pulp exposure occurs. One of the primary considerations in prosthodontic restoration for tooth wear is vertical dimension. It is necessary to make an accurate diagnosis and analysis, correct judgement of the interdental relationship for predictive treatment plan. A step-by-step approach considering dental care for aged is also required. In this case, a 93-year-old male patient presented with worn dentition and mobility of existing fixed dental prosthesis. After diagnosis and evaluation, maxillary rehabilitation without any change in the occlusal vertical dimension was performed and this shows satisfactory results both functionally and morphologically.

• Journal of the Korean Ceramic Society
• /
• v.56 no.4
• /
• pp.403-411
• /
• 2019

In this work, the hydration process and cytotoxicity of lab-synthesized experimental Portland cements (EPCs) were investigated for dental applications. For this purpose, EPCs were prepared using laboratory-synthesized clinker constituents, tricalcium silicate (C₃S), dicalcium silicate (C₂S), and tricalcium aluminate (C₃A). C-A was prepared by the Pechini method, whereas C₃S and C₂S were synthesized by solid-state reactions. The phase compositions were characterized by X-ray diffraction (XRD) analysis, and the hydration process of the individual constituents and their combinations, with and without the addition of gypsum, was investigated by electrochemical impedance spectroscopy (EIS). Furthermore, four EPC compositions were prepared using the lab-synthesized C-A, C₃S, and C₂S, and their hydration processes were examined by EIS, and their cytotoxicity to HPC and HIPC cells were tested by performing an XTT assay. None of the EPCs exhibited any significant cytotoxicity for 7 days, and no significant difference was observed in the cell viabilities of ProRoot MTA and EPCs. The results indicated that all the EPCs are sufficiently biocompatible with human dental pulp cells and can be potential substitutes for commercial dental cements.

• Restorative Dentistry and Endodontics
• /
• v.45 no.1
• /
• pp.7.1-7.9
• /
• 2020

Objectives: This study was performed to assess the anatomy of mandibular first molars. Materials and Methods: In this in vivo study, cone-beam computed tomography (CBCT) volumes of 312 bilateral intact first mandibular molars from 156 patients (79 men and 77 women; average age, 35.6 ± 11.2 years) were investigated in terms of the direction of each canal's curvature in the buccolingual and mesiodistal dimensions (direction of the position of the apex in relation to the longitudinal axis of the root), the presence of an isthmus (a narrow, ribbon-shaped communication between 2 root canals) in 3 segments (0-2, 2-4, and 4-6 mm) from the apex), and the presence and number of accessory canals (smaller canals besides the main root canals, connecting the pulp to the periodontium). Data were analyzed statistically (α = 0.05). Results: Mesiolingual canals were mostly buccally and distally inclined, while mesiobuccal and distolingual canals were mostly distally curved. Isthmuses were more common in younger patients (χ² test, p < 0.05). The average numbers of accessory canals in the apical, middle, and coronal segments were 9.9 ± 4.2, 6.9 ± 2.9, and 9.3 ± 3.0 canals per segment, respectively (analysis of variance, p < 0.001). Age and sex were not associated with the number of accessory canals (p > 0.05). Conclusions: The complex anatomy of these teeth deserves attention during non-surgical or surgical endodontic treatment. Around the apex, isthmuses might be more prevalent in younger and female individuals.

• Journal of The Korean Dental Society of Anesthesiology
• /
• v.11 no.1
• /
• pp.16-21
• /
• 2011

Background: Since introduced by Gow-Gates GA in 1973, Gow-Gates mandibular nerve block (GMNB) has played an important role in the area of dental local anesthesia. However, compared to the conventional inferior alveolar nerve block (IANB), this technique seems to fail to attract the attentions of general practitioners in South Korea. The aim of this study was to prove the clinical real value, mainly the anesthetic efficacy, of GMNB in minor oral surgery. Methods: The study group comprised 40 patients (15 males and 25 females) who were randomly allocated to receive GMNB or IANB for extraction of third molars. Both techniques utilized two 1.8 ml dental cartridges of 2% lidocaine including 1:100,000 epinephrine for each patient. Pulpal and gingival tissue anesthesia of mandibular premolars and molars were recorded at 0, 15 and 40 minutes after administration of local anesthetics using both an electric pulp tester and a sharp dental explorer. Results: The success rates of pulpal and gingival tissue anesthesia in the IANB group were not significantly different from the GMNB group in overall efficacy. Patient's and operator's satisfaction ratings were also not significantly different between two groups. Interestingly, the injection pain of GMNB group was significantly lower than that of IANB group. Conclusion: This study demonstrated that the anesthetic efficacy of pulpal and gingival tissue of GMNB was not inferior to that of IANB. The GMNB could be a good alternative of the IANB in most of minor oral surgical procedures.

• Journal of Korean Dental Science
• /
• v.13 no.2
• /
• pp.52-58
• /
• 2020

Purpose: Using two types of electronic apex locators, this study aimed to investigate the differences in accuracy according to the evaluator and equipment. Materials and Methods: Artificial teeth of the lower first premolars and two mandibular acrylic models (A and B) were used in this study. In the artificial teeth, the pulp chamber was opened and the access cavity was prepared. Using calibrated digital Vernier calipers, the distance from the top of the cavity and the root apex was measured to assess the actual distance between two artificial teeth. The evaluation was conducted by 20 dentists, and each evaluator repeated measurements for each electronic apex locator five times. The difference between the actual distance from the top of the cavity to the root apex and the distance measured using electronic measuring equipment was compared. For statistical analysis, the Friedman test the Mann-Whitney U-test were conducted and the differences between groups were analyzed (α=0.05). Result: As for the accuracy of measurement according to the two types of electronic apex locators, the value of the measurement error was 0.4753 mm in Dentaport ZX and 0.3321 mm in E-Cube Plus. Moreover, electronic apex locators Dentaport ZX and E-Cube Plus showed statistically significant differences (P<0.05). As for the difference in the accuracy of the two types of electronic apex locators according to the evaluator, the resulting values differed depending on the evaluator and showed a statistically significant difference (P<0.001). Conclusion: Electronic apex locator E-Cube Plus showed higher accuracy than did Dentaport ZX. Nevertheless, both types of electronic apex locators showed 100% accuracy in finding the region within root apex ±0.5 mm zone. Furthermore, according to the evaluator, the two electronic apex locators showed different resulting values.