• Restorative Dentistry and Endodontics
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• v.1 no.1
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• pp.11-17
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• 1975

This study is to determine the penetration of various medicaments such as Howe's ammoniacal silver nitrate and methyleneblue, to root canal dentin within given time (5,10,30 sec.) Followings are the results obtained from this study. 1) The dye stuff is more deeply penetrated according to the time elapsed. 2) According to the increase of age, the penetration ratio is decreased accordingly. 3) The penetration ratio of Howe's ammoniacal silver nitrate is higher than that of methyleneblue. 4) The permeability of the root canal dentin is gradually reduced as access to the apex.

• Restorative Dentistry and Endodontics
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• v.45 no.2
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• pp.21.1-21.12
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• 2020

The aim of this article was to review age-dependent clinical recommendations for appropriate root canal instrumentation techniques. A comprehensive narrative review of canal morphology, the structural characteristics of dentin, and endodontic outcomes at different ages was undertaken instead of a systematic review. An electronic literature search was carried out, including the Medline (Ovid), PubMed, and Web of Science databases. The searches used controlled vocabulary and free-text terms, as follows: 'age-related root canal treatment,' 'age-related instrumentation,' 'age-related chemo-mechanical preparation,' 'age-related endodontic clinical recommendations,' 'root canal instrumentation at different ages,' 'geriatric root canal treatment,' and 'pediatric root canal treatment.' Due to the lack of literature with practical age-based clinical recommendations for an appropriate root canal instrumentation technique, a narrative review was conducted to suggest a clinical algorithm for choosing the most appropriate instrumentation technique during root canal treatment. Based on the evidence found through the narrative review, an age-related clinical algorithm for choosing appropriate instrumentation during root canal treatment was proposed. Age affects the morphology of the root canal system and the structural characteristics of dentin. The clinician's awareness of root canal morphology and dentin characteristics can influence the choice of instruments for root canal treatment.

• Restorative Dentistry and Endodontics
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• v.41 no.1
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• pp.29-36
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• 2016

Objectives: The purpose of this study was to assess the ability of two new calcium silicate-based pulp-capping materials (Biodentine and BioAggregate) to induce healing in a rat pulp injury model and to compare them with mineral trioxide aggregate (MTA). Materials and Methods: Eighteen rats were anesthetized, cavities were prepared and the pulp was capped with either of ProRoot MTA, Biodentine, or BioAggregate. The specimens were scanned using a high-resolution micro-computed tomography (micro-CT) system and were prepared and evaluated histologically and immunohistochemically using dentin sialoprotein (DSP). Results: On micro-CT analysis, the ProRoot MTA and Biodentine groups showed significantly thicker hard tissue formation (p < 0.05). On H&E staining, ProRoot MTA showed complete dentin bridge formation with normal pulpal histology. In the Biodentine and BioAggregate groups, a thick, homogeneous hard tissue barrier was observed. The ProRoot MTA specimens showed strong immunopositive reaction for DSP. Conclusions: Our results suggest that calcium silicate-based pulp-capping materials induce favorable effects on reparative processes during vital pulp therapy and that both Biodentine and BioAggregate could be considered as alternatives to ProRoot MTA.

• Restorative Dentistry and Endodontics
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• v.6 no.1
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• pp.7-16
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• 1980

The author observed the periodontal tissue reactions to the root canal sealers after root perforations were made intentionally in dogs. The perforations were made on 74 teeth from 7 dogs. The experiments were performed in two different modes of procedure: In Group I, the perforations were made through the root canal to the alveolar bone. In Group II, the perforations were made from site of alveolar bone to the root canals. The perforated canals in Group I were filled with gutta-percha and root canal cements; Calxyl (Calcium Hydroxide in Ringer's solution), Zinc Oxide -Eugenol cement (Z.O.E.), Kerr sealer (Rickert's paste) and AH 26 (Epoxy Resin preparations). The perforated canals in Group II were sealed with Calxyl, Z.O.E, Kerr sealer and AH26. Histologic examinations of periodontal tissue reactions were observed at various time intervals. The results were as follows; l. Cementum deposition on the perforated root surface in Group II cases showed slightly earlier than that of Group I. Healing tendency of injured alveolar bone in Group II was greater than that of Group I. 2. According to the time increase after experiment, the cementum deposition on the site of perforated dentin in Group II with intact pulp was notably thickened. Secondary dentin deposition on the root canal surface where the dentinal tubles were cut was also found in similar pattern. 3. In the cases of perforated canals sealed with Calxyl both in Group I and Group II, It revealed the earliest cementum-deposition among 4 different root canal cements. In the cases of perforated canals sealed with Kerr sealer and AH26, the cementum-deposition on the root surface was not found. 4. Proliferation of epithelium around the perforated area was first seen at 5-week cases in Group I, and at 3-week cases in Group II. 5. In all cases, dentin resorption on the site of perforated root surface was always occured.

• Restorative Dentistry and Endodontics
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• v.15 no.2
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• pp.93-103
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• 1990

The primary purpose of this study was to assess the effect of the EDTA on human dentin hardness of root. The 30 extracted human anterior teeth were divided into three groups, and EDTA was applied on the each tooth root dentin surface for 5, 15 and 30 minutes to evaluate the dentin hardness. The following results were obtained : 1. The KHN of dentin was decreased by 21.3% from 50.8 to 40.0 in 5 min. group, 44.2% from 48.4 to 27.0 in 15 min. group, and 51.9% from 48.0 to 23.1 in 30 min group. 2. The decrease rate per 1 min. of KHN of dentin was 4.3 in 5 min. group, 2.9 in 15 min. group, and 1.7 in 30 min. group. 3. As time passed, the KHN of dentin of 5 min. group and 15 mim. group were significantly decreased, but the KHN of dentin of 30 min. was not significantly decreased compared with 15 min. group. There was a statistical significance in the decrease rate of KHN of dentin among 3 groups(P<0.05).

• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.39.1-39.11
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• 2020

Despite the vast literature on the effects of root canal irrigants on the dentin characteristics, the precise effects of clinically relevant irrigation sequences remain unclear. In this review, we systematically dissect the role of different sequential irrigation approaches that are used in clinical endodontics. Using a systematic search strategy, we attempt to answer the question: 'Which irrigating sequence has the most deleterious effects on dentin structure and properties?' The effect of irrigants on the dentin composition and mechanical properties have been reviewed. A wide variety of concentrations, duration and techniques have been employed to characterize the effects of chemicals on dentin properties, thus making it impossible to draw guidelines or recommendations of irrigant sequences to be followed clinically. It was apparent that all the studied irrigation sequences potentially result in some deleterious effects on dentin such as decrease in the flexural strength, microhardness, modulus of elasticity and inorganic content and organic-inorganic ratio of the dentin. However, the literature still lacks comprehensive investigations to compare the deleterious effect of different irrigation sequences, using a wide variety of qualitative and quantitative methods. Such investigations are essential to make clinical recommendations and strategize efforts to minimize chemically-induced damage to dentin characteristics.

• Restorative Dentistry and Endodontics
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• v.29 no.5
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• pp.446-453
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• 2004

The aim of this study was to evaluate the shaping abilities of four different rotary nickel-titanium instruments with anticurvature motion to prepare root canal at danger zone by measuring the change of dentin thickness in order to have techniques of safe preparation of canals with nickel-titanium files. Mesiobuccal and mesiolingual canals of forty mesial roots of extracted human lower molars were instrumented using the crown-down technique with ProFile, $GT^{TM}$ Rotary file, Quantec file and $ProTaper^{TM}$. In each root, one canal was prepared with a straight up-and-down motion and the other canal was with an anticurvature motion. Canals were instrumented until apical foramens were up to size of 30 by one operator. The muffle system was used to evaluate the root canal preparation. After superimposing the pre- and post-instrumentation canal. change in root dentin thickness was measured at the inner and outer sides of the canal at 1. 3, and 5 mm levels from the furcation. Data were analyzed using two-way ANOVA. Root dentin thickness at danger zone was significantly thinner than that at safe zone at all levels (p < 0.05). There was no significant difference in the change of root dentin thickness between the straight up-and-down and the anticurvature motions at both danger and safe zones in all groups (p > 0.05). ProTaper removed significantly more dentin than other files especially at furcal 3 mm level of danger and safe zones (p < 0.05) Therefore, it was concluded that anticurvature motion with nickel-titanium rotary instruments does not seem to be effective in danger zone of lower molars.

• Restorative Dentistry and Endodontics
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• v.39 no.2
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• pp.95-103
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• 2014

Objectives: This study evaluated the effect of three antioxidizing agents on pullout bond strengths of dentin treated with sodium hypochlorite. Materials and Methods: Root canals of 75 single-rooted human teeth were prepared. Fifteen teeth were irrigated with normal saline for a negative control group, and the remaining 60 teeth (groups 2 - 5) with 2.5% NaOCl. The teeth in group 2 served as a positive control. Prior to post cementation, the root canals in groups 3 - 5 were irrigated with three antioxidizing agents including 10% rosmarinic acid (RA, Baridge essence), 10% hesperidin (HPN, Sigma), and 10% sodium ascorbate hydrogel (SA, AppliChem). Seventy-five spreaders (#55, taper .02, Produits Dentaires S.A) were coated with silica and silanized with the Rocatec system and ceramic bond. All the prepared spreaders were cemented with a self-adhesive resin cement (Bifix SE, Voco Gmbh) in the prepared canals. After storage in distilled water (24 h/$37^{\circ}C$), the spreaders were pulled out in a universal testing machine at a crosshead speed of 1.0 mm/min. Pull-out strength values were analyzed by one-way ANOVA and Tukey's HSD test (${\alpha}$ = 0.05). Results: There were significant differences between study groups (p = 0.016). The highest pullout strength was related to the SA group. The lowest strength was obtained in the positive control group. Conclusions: Irrigation with NaOCl during canal preparation decreased bond strength of resin cement to root dentin. Amongst the antioxidants tested, SA had superior results in reversing the diminishing effect of NaOCl irrigation on the bond strength to root dentin.

• Restorative Dentistry and Endodontics
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• v.20 no.1
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• pp.142-151
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• 1995

The purpose of this study was to compare and estimate the physical properties of five root canal sealers classified Calciobiotic root canals sealer as calcium hydroxide based sealer, Apatite root sealer type II as calcium phosphate based sealer, AH-26 as resin based sealer, Canals and Pulpdent root canals sealer as zinc oxide eugenol based sealer. The author investigated dimensional change and flow rate of canal sealers, diametral tensile strength and shear bond strength of sealers to dentin to evaluate the physical properties on affect of complete obturation of root canal and performed the total 100 specimens of each 25 sealers under the condition of root temperature according to manufacturer's instructions. All specimens were stored at $37{\pm}1^{\circ}C$ in 100 % relative humidity. A microscope for measurement of micro distance is used for the dimensional change test and evacuation methods using vaccum were used for the flow rate test. The result differed by the storage time measured on the tests of diametral tensile strength and shear bond strength to dentin. The following results were obtained ; 1 On the test of dimensional change, Canals and Pulpdent expanded slightly, AH-26 and Apatite showed the severe shrinkage after 48 hours. 2. AH-26 and Apatite were the excellent with each 24.59mm, 31.19mm after 3 minutes in the aspect of flow property. 3. On the diametral tensile strength, Calciobiotic root canals sealer showed the highest strength with 27.13kg/$cm^2$ after 48 hours, Apatite root sealer type II showed highest strength with 84.57kg/$cm^2$ after 120 hours. 4. On the shear bond strength to dentin, AH-26 was most excellent with 55.73kgf/$cm^2$ after 24 hours and with 134.71kgf/$cm^2$ after 120 hours.

• Restorative Dentistry and Endodontics
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• v.48 no.1
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• pp.8.1-8.8
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• 2023

Objectives: This study was designed to evaluate the parameters of bonding performance to root dentin, including push-out bond strength and dentinal tubular biomineralization, of a hydraulic bioceramic root-end filling material premixed with dimethyl sulfoxide (Endocem MTA Premixed) in comparison to a conventional powder-liquid-type cement (ProRoot MTA). Materials and Methods: The root canal of a single-rooted premolar was filled with either ProRoot MTA or Endocem MTA Premixed (n = 15). A slice of dentin was obtained from each root. Using the sliced specimen, the push-out bond strength was measured, and the failure pattern was observed under a stereomicroscope. The apical segment was divided into halves; the split surface was observed under a scanning electron microscope, and intratubular biomineralization was examined by observing the precipitates formed in the dentinal tubule. Then, the chemical characteristics of the precipitates were evaluated with energy-dispersive X-ray spectroscopic (EDS) analysis. The data were analyzed using the Student's t-test followed by the Mann-Whitney U test (p < 0.05). Results: No significant difference was found between the 2 tested groups in push-out bond strength, and cohesive failure was the predominant failure type. In both groups, flake-shaped precipitates were observed along dentinal tubules. The EDS analysis indicated that the mass percentage of calcium and phosphorus in the precipitate was similar to that found in hydroxyapatite. Conclusions: Regarding bonding to root dentin, Endocem MTA Premixed may have potential for use as an acceptable root-end filling material.