• Restorative Dentistry and Endodontics
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• 제48권1호
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• pp.1.1-1.11
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• 2023

Objectives: This study evaluated the dentinal penetration depth of 2.5% sodium hypochlorite (NaOCl) in root canals with and without preparation and different irrigant activation protocols. Materials and Methods: Sixty-three bovine mandibular incisors were randomly allocated to 6 groups (n = 10): G1, preparation + conventional needle irrigation (CNI); G2, preparation + passive ultrasonic irrigation (PUI); G3, preparation + Odous Clean (OC); G4, no preparation + CNI; G5, no preparation + PUI; G6, no preparation + OC; and CG (negative control; n = 3). Samples were filled with crystal violet for 72 hours. Irrigant activation was performed. Samples were sectioned perpendicularly along the long axis, 3 mm and 7 mm from the apex. Images of the root thirds of each block were captured with a stereomicroscope and analyzed with an image analysis software. One-way analysis of variance, followed by the Tukey post hoc test, and the Student's t-test were used for data analysis, with a significance level of 5%. Results: The NaOCl penetration depth was similar when preparation was performed, regardless of the method of irrigation activation (p > 0.05). In the groups without preparation, G6 showed greater NaOCl penetration depth (p < 0.05). The groups without preparation had a greater NaOCl penetration depth than those with preparation (p = 0.0019). Conclusions: The NaOCl penetration depth was similar in groups with root canal preparation. Without root canal preparation, OC allowed deeper NaOCl penetration. The groups without preparation had greater NaOCl penetration than those undergoing root canal preparation.

• 대한소아치과학회지
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• 제42권2호
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• pp.188-196
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• 2015

치내치를 동반한 미성숙 영구치의 근관치료를 성공적으로 수행하는 것은 치과의사에게 어려운 과제이다. 복잡한 형태의 근관계는 근관 내부를 효과적으로 성형, 멸균, 충전하는 것이 어렵기 때문에 포괄적이고 철저한 치료계획을 수립하는 것이 중요하다. 본 증례는 치내치를 동반한 감염된 미성숙 영구치를 가진 두명의 환자에게 재생형 근관치료를 시행하여 양호한 결과를 얻었기에 이를 보고하고자 한다. 감염된 괴사치수와 각각 Oehlers type I, type III 치내치를 포함하는 두개의 미성숙 상악 측절치에 재생형 근관치료가 시행되었다. 특히 Type III 치내치의 근관치료는 보다 효과적인 감염조절과 근관 충전을 위해 복잡한 근관 내부 구조를 재형성하는 드문 접근법을 이용하였다. 이 때, Cone-beam computed tomography (CBCT)와 미세 수술 현미경의 사용은 근관 내부의 시각화 및 치료에 도움이 되었다. 결과적으로, 복잡한 형태의 치내치를 포함하는 미성숙 영구치의 재생형 근관치료는 임상적, 방사선학적 치유 뿐만 아니라 치근 상아질 벽의 두께 증가를 가능하게하는 효과적인 치료 방법이 될 수 있을 것으로 생각된다.

• 대한치과의사협회지
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• 제54권8호
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• pp.658-665
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• 2016

Treatment of immature permanent teeth with irreversibly damaged pulp has been challenging in dental practice because of the lack of apical constriction, thin dentinal walls, and short roots. This may lead to the extrusion of filling materials, and fracture of the root due to its more fragile feature during shaping of the root canal. Apexification with calcium hydroxide or MTA is one of the treatment options for these cases. Although favorable results of apexification have been reported, these treatment procedures do not guarantee the increase of root length and/or width even after a long term period. Thus, treated teeth are still prone to fractures. Recently, pulp revascularization has been proposed as an alternative treatment for immature teeth with necrotic pulp and periapical pathosis. Pulp revascularization allows the stimulation of the apical development and the root maturation. There have been many treatment protocols using various materials such as antibiotics and calcium hydroxide medicament. In this case report, literature review about pulp revascularization and two related cases are presented.

• Restorative Dentistry and Endodontics
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• 제40권4호
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• pp.314-321
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• 2015

Tooth related factors such as palatoradicular groove can be one of the causes for localized periodontal destruction. Such pathological process may result in apicomarginal defect along with inflammation of pulp. This creates challenging situation which clinician must be capable of performing advanced periodontal regenerative procedures for the successful management. This case report discusses clinical management of apicomarginal defect associated with extensive periradicular destruction in a maxillary lateral incisor, along with histopathologic aspect of the lesion.

• Restorative Dentistry and Endodontics
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• 제13권1호
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• pp.7-19
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• 1988

The object of this paper was to investigate the histopatological changes on dog's pulp under cavitation by irradiation of the $CO_2$ laser. The subjects were derived from four dogs, and irradiated 113.23 J/$mm^2$, 283.09 J/$mm^2$, 566.08 J/$mm^2$ in Group I, II, and III respectively. The dogs were sacrificed immediately, 24 hour, 72 hour and 1 week after $CO_2$ laser treatment. For light microscopic examination, routine H-E and PAS stains were employed. For electron microscopic observation, the teeth were fixed in 1% paraformaldehyde and 1% glutaraldehyde, decalcified teeth in 10% EDTA were stained by uranyl acetate and lead citrate. The observation was made with a Hitachi H-500 model electron microscope. The following results were obtained in this study: 1. At the early stage of the experimental sub-groups-immediately, 24 hour, 72 hour samples of Group I, II and III-coagulation necrosis and hyperemia were observed in odontoblastic and subodontoblastic pulpal layer. 2. At the 1 week sub-group of Group I, II, regenerative hyperplasia of the odontoblasts without coagulation necrosis were revealed, in addition to thickened predentin. On he other hand coagulation necrosis and atrophic change accompanying with hyperplasia were found at the 1 week sub-group of Group III. 3. Ultrastructurally, the odontoblasts appeared nuclear degeneration, vacuolar change of cytoplasmic organelles and rupture of plasma membrane at the early stage of the experimental period of all groups. 4. Under spectrohelioscopic examination, regenerative odontobalsts were seen at the 1 week specimens of Group I, II and III. 5. The pulpal response occured at 113-566 J/$mm^2$. The pathologic change of pulp tissue occured at the early experimental period but regeneration of odontoblasts could be seen after 1 week.

• Restorative Dentistry and Endodontics
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• 제41권1호
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• pp.44-54
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• 2016

Objectives: The purpose of this study was to evaluate the histopathological effects of an antioxidant therapy on the pulp tissue of rat teeth exposed to a bleaching gel with 35% hydrogen peroxide. Materials and Methods: Forty rats were subjected to oral ingestion by gavage of distilled water (DW) or ascorbic acid (AA) 90 min before the bleaching therapy. For the bleaching treatment, the agent was applied twice for 5 min each to buccal surfaces of the first right mandibular molars. Then, the animals were sacrificed at 6 hr, 24 hr, 3 day, or 7 day post-bleaching, and the teeth were processed for microscopic evaluation of the pulp tissue. Results: At 6 hr, the pulp tissue showed moderate inflammatory reactions in all teeth of both groups. In the DW and AA groups, 100% and 80% of teeth exhibited pulp tissue with significant necrosis and intense tissue disorganization, respectively. At 24 hr, the AA-treated group demonstrated a greater regenerative capability than the DW group, with less intense inflammatory reaction and new odontoblast layer formation in 60% of the teeth. For up to the 7 day period, the areas of pulpal necrosis were replaced by viable connective tissue, and the dentin was underlined by differentiated odontoblast-like cells in most teeth of both groups. Conclusions: A slight reduction in initial pulpal damage during post-bleaching was promoted by AA therapy. However, the pulp tissue of AA-treated animals featured faster regenerative potential over time.

• Restorative Dentistry and Endodontics
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• 제41권4호
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• pp.283-295
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• 2016

Objectives: In this study, we characterized human dental pulp cells (HDPCs) obtained by different culture methods to establish the most suitable methodology for dental tissue engineering and regenerative endodontic applications. Materials and Methods: HDPCs were isolated by the outgrowth method (HDPCs-OG), the enzymatic digestion method (collagenase/dispase/trypsin, HDPCs-ED), or the combination of both methods (HDPCs-Combined). The expression of mesenchymal stem cell markers (CD105, CD90, and CD73) was investigated. In vitro differentiation capacities of HDPCs into adipogenic, osteogenic, and chondrogenic lineages were compared. Differentiation markers were analyzed by quantitative reverse-transcription polymerase chain reaction (RT-PCR) and western blotting. Results: Our data indicated that whole HDPCs-ED, HPDCs-OG, and HDPCs-Combined could be differentiated into adipogenic, chrondrogenic, and osteogenic cell types. However, we found that the methods for isolating and culturing HDPCs influence the differentiation capacities of cells. HDPCs-OG and HDPCs-ED were preferably differentiated into adipogenic and osteogenic cells, respectively. Differentiation markers shown by RT-PCR and western blotting analysis were mostly upregulated in the treated groups compared with the control groups. Conclusions: Our findings confirmed that cell populations formed by two different culture methods and the combined culture method exhibited different properties. The results of this study could provide an insight into regenerative endodontic treatment using HDPCs.

• Restorative Dentistry and Endodontics
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• 제44권4호
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• pp.35.1-35.10
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• 2019

Pulp revascularization is an alternative treatment in immature traumatized teeth with necrotic pulp. However, this procedure has not been reported in horizontal root fractures. This is a case report of a 9-year-old patient with multiple horizontal root fractures in 2 upper central incisors that were successfully treated with pulp revascularization. The patient presented for treatment 2 years after the initial trauma, and revascularization was attempted after the initial treatment with calcium hydroxide had failed. Prior to pulp revascularization, cone-beam computed tomography and autoradiograms demonstrated multiple horizontal fractures in the middle and apical thirds of the roots of the 2 affected teeth. Revascularization was performed in both teeth; platelet-rich plasma (PRP) was used in one tooth (#11) and the conventional method (blood clot) was used in the other tooth (#21). Clinical and radiographic follow-up over 4 years demonstrated pulp calcification in the PRP-treated tooth. Neither of the 2 teeth were lost, and the root canal calcification of tooth #11 was greater than that of tooth #21. This case suggests that PRP-based pulp revascularization may be an alternative for horizontal root fractures.

• Restorative Dentistry and Endodontics
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• 제40권4호
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• pp.290-298
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• 2015

Objectives: Sodium hypochlorite (NaOCl) is an excellent bactericidal agent, but it is detrimental to stem cell survival, whereas intracanal medicaments such as calcium hydroxide ($Ca[OH]_2$) promote the survival and proliferation of stem cells. This study evaluated the effect of sequential NaOCl and $Ca(OH)_2$ application on the attachment and differentiation of dental pulp stem cells (DPSCs). Materials and Methods: DPSCs were obtained from human third molars. All dentin specimens were treated with 5.25% NaOCl for 30 min. DPSCs were seeded on the dentin specimens and processed with additional 1 mg/mL $Ca(OH)_2$, 17% ethylenediaminetetraacetic acid (EDTA) treatment, file instrumentation, or a combination of these methods. After 7 day of culture, we examined DPSC morphology using scanning electron microscopy and determined the cell survival rate with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. We measured cell adhesion gene expression levels after 4 day of culture and odontogenic differentiation gene expression levels after 4 wk using quantitative real-time polymerase chain reaction. Results: DPSCs did not attach to the dentin in the NaOCl-treated group. The gene expression levels of fibronectin-1 and secreted phosphoprotein-1 gene in both the $Ca(OH)_2$- and the EDTA-treated groups were significantly higher than those in the other groups. All $Ca(OH)_2$-treated groups showed higher expression levels of dentin matrix protein-1 than that of the control. The dentin sialophosphoprotein level was significantly higher in the groups treated with both $Ca(OH)_2$ and EDTA. Conclusions: The application of $Ca(OH)_2$ and additional treatment such as EDTA or instrumentation promoted the attachment and differentiation of DPSCs after NaOCl treatment.

• Restorative Dentistry and Endodontics
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• 제46권4호
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• pp.52.1-52.11
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• 2021

Objectives: This study evaluated the effects of low and moderate concentrations of triple antibiotic paste (TAP) and double antibiotic paste (DAP) loaded into a hydrogel system on crown discoloration and explored whether application of an adhesive bonding agent prevented crown discoloration. Materials and Methods: Intact human molars (n = 160) were horizontally sectioned 1 mm apical to the cementoenamel junction. The crowns were randomized into 8 experimental groups (calcium hydroxide, Ca[OH]₂; 1, 10, and 1,000 mg/mL TAP and DAP; and no medicament. The pulp chambers in half of the samples were coated with an adhesive bonding agent before receiving the intracanal medicament. Color changes (ΔE) were detected by spectrophotometry after 1 day, 1 week, and 4 weeks, and after 5,000 thermal cycles, with ΔE = 3.7 as a perceptible threshold. The 1-sample t-test was used to determine the significance of color changes relative to 3.7. Analysis of variance was used to evaluate the effects of treatment, adhesive, and time on color change, and the level of significance was p < 0.05. Results: Ca(OH)₂ and 1 and 10 mg/mL DAP did not cause clinically perceivable tooth discoloration. Adhesive agent use significantly decreased tooth discoloration in the 1,000 mg/mL TAP group up to 4 weeks. However, adhesive use did not significantly improve coronal discoloration after thermocycling when 1,000 mg/mL TAP was used. Conclusions: Ca(OH)₂ and 1 and 10 mg/mL DAP showed no clinical discoloration. Using an adhesive significantly improved coronal discoloration up to 4 weeks with 1,000 mg/mL TAP.