Residual Calcium Hydroxide Research Articles

Evaluation of the Effect of Calcium Hydroxide Residues Including Different Vehicles on the Accuracy of Electronic Apex Locators

Aim: This study aimed to evaluate the effect of the residues of the calcium hydroxide (CH) dressings with different vehicles on the accuracy of two different electronic apex locators (EALs). Materials and Method: Endodontic access cavities were prepared at 120 single-rooted maxillary premolars. The actual length (AL) was determined under a stereomicroscope at ×15 magnification. After the preparation of the canals, electronic length (EL1) was measured using Propex Pixi and EndoRadar Pro. Samples were divided into one control (without CH) and five experimental groups according to the different CH vehicles (saline, mono propylene glycol, methylcellulose, silicone oil, and chlorhexidine), and calcium CH dressing was placed. After the removal of CH using 4 mL of 17% EDTA irrigation with EDDY, EL was measured again and recorded as EL2. The difference was calculated by subtracting AL from EL1 and EL2. The amount of CH residues was assessed using software. Results: There was no significant difference among the groups after removal of the CH dressing for both EALs ( p > .05). The type of vehicle did not affect the residual amount of CH. Due to the residual CH, the accuracy of both EALs was compromised. However, the success rate of Propex Pixi was significantly reduced in the presence of CH remnants. Conclusion: Propex Pixi and EndoRadar were more accurate in the measurements before the application of CH dressing than after. There was no discernible impact of vehicle type on the residual amount of CH. This study emphasizes the necessity of completely removing CH dressings prior to the use of EAL to enhance the accuracy of the working length determination in endodontic practice.

Comparative Evaluation Of Retrievability Of Calcium Hydroxide From Apical Third Of Root Canal With Commercially Available Root Canal Irrigants: An InVitro Study

Context: Calcium hydroxide is the most widely used intracanal medicament to aid chemomechanical preparation to thoroughly clean the root canal system. However, it is important to completely remove the medicament for predictable success of the root canal treatment. Aim: This study was aimed to compare the effectiveness of irriganting solutions and irrigation methods to remove calcium hydroxide from the root canal system. Material and Methodology: Eighty extracted single rooted teeth were selected and instrumented using ProTaper Gold rotary files, followed by application of calcium hydroxide. After incubating for a week, teeth were randomly allocated into 8 groups (n=10) based on irrigating solution (17% EDTA, 1% Phytic Acid, 3% NaOCl, 70% Ethanol) and method of irrigation used (PUI and NAI). The sample teeth were then sectioned horizontally to assess the residual calcium hydroxide on the canal walls under Confocal Laser Scanning Microscope. Statistical analysis: The difference in the mean value of the two parameters was assessed by using analysis of variance (ANOVA). Tukey’s test was used for post hoc multiple comparisons between different groups. The level of significance was fixed at p<0.05. Results: None of the irrigants were able to completely remove the calcium hydroxide from the root canal. However, irrigation with 70% Ethanol presented significantly cleaner root canal walls in NAI. Conclusion: 70% Ethanol presented with least amount of residual calcium hydroxide in comparison with phytic acid and commercially available irrigants i.e., EDTA and NaOCl in both NAI and PUI.

Retrievability of Intracanal Medicament from Root Canals: An In-vitro CBCT Volumetric Analysis

Introduction: The complete removal of Calcium Hydroxide {Ca(OH)2 } using various techniques remains a challenge in root canal therapy. One of the most commonly used methods for removing calcium hydroxide is by using a Master Apical File (MAF) along with sodium hypochlorite and Ethylenediaminetetracetic Acid (EDTA). Various new modalities, like Canal Brush, NaviTip and file systems, have emerged to tackle the residual calcium hydroxide in the canal; but none of these methods have been able to completely remove it from the canal. Aim: To evaluate and compare the efficacy of H-files, NaviTip FX and Canal Brushes in removing calcium hydroxide intracanal medicament from root canals. Materials and Methods: This in-vitro study was carried out in the Department of Conservative Dentistry and Endodontics at KM Shah Dental College and Hospital, Vadodara, Gujarat, India, from December 2023 to March 2024. To standardise the length at 14 mm, 30 mandibular premolar teeth (n=30) with a single root were decoronated at the Cementoenamel Junction (CEJ). The working length was determined, followed by the cleaning and shaping of all specimens using ProTaper Rotary Files. Intracanal medicament (Metapex) was placed and the canals were sealed with Glass Ionomer Cement (GIC). The specimens were then placed at 37±1ºC and 100% relative humidity for 30 days. The medicament was subsequently removed by three different protocols: H-file, NaviTip FX and Canal Brush (n=10 each). The residual volumes in the mesial, distal and apical thirds were assessed, referring to the volume of medicament left in the canal, which was measured using Cone-beam Computed Tomography (CBCT). The recorded variables were analysed using one-way Analysis of Variance (ANOVA) post-hoc tests (p<0.05). Results: The Canal Brush removed the maximum amount of Metapex in the apical third (0.108) of the roots of the premolars, followed by NaviTip FX and then H-file. In the middle third of the root, NaviTip FX removed more Metapex than the Canal Brush, followed by H-files. A comparison of retrieval between and within the groups it showed that none of the techniques were capable of removing all the Metapex from the specimens, with p>0.05. Conclusion: The present study demonstrated that the Canal Brush showed superior results in retrieving Metapex from the apical third of the root and the distal side (middle third), whereas NaviTip FX removed more Metapex from the mesial side (middle third) of the root, but H-file exhibited the least efficacy in the retrieval of Metapex. Total removal of calcium hydroxide from the entire canal is not possible regardless of the technique used.

Efficacy of laser-activated irrigation with the SWEEPS modality in removing calcium hydroxide from simulated internal resorption cavities

Aim: To compare the efficacy of shockwave-enhanced emission photoacoustic streaming (SWEEPS), sonic activation with EDDY, and passive ultrasonic irrigation (PUI) in the removal of calcium hydroxide medicaments from artificial internal resorption cavities. Methodology: Ninety mandibular premolars with single oval canals were prepared to size 50/0.04 and split longitudinally. Standardized cavities were prepared in the apical third of the root canal and filled with calcium hydroxide. The root halves were reassembled and divided into three groups (n = 30) according to the removal methods used. The amount of residual calcium hydroxide was evaluated using a four-grade scoring system. The differences between the groups were analyzed using the Kruskal–Wallis H test (p < 0.05). Results: SWEEPS removed significantly more calcium hydroxide than PUI (p < 0.003) and EDDY (p < 0.035). There was no significant difference between the EDDY and PUI groups (p = 1.000). Conclusion: None of the systems tested were able to completely remove the calcium hydroxide paste from the simulated internal resorption cavities; however, SWEEPS removed more calcium hydroxide than the EDDY and PUI techniques. How to cite this article: Erkan E, Aydın RN, Falakaloğlu S, Yeniçeri Özata M, Gündoğar M. Efficacy of laser-activated irrigation with the SWEEPS modality in removing calcium hydroxide from simulated internal resorption cavities. Int Dent Res 2023;13(2):48-53. https://doi.org/10.5577/idr.2023.vol13.no2.1 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Efficacy of Three Irrigation Methods in Removing Calcium Hydroxide from Curved Root Canals: An In Vitro Micro-CT Study.

This in vitro study aimed to compare the efficacy of three different irrigation methods in removing calcium hydroxide from curved root canals and to estimate the amount of residual medicament using microcomputed tomography. Thirty extracted molars with curved mesial root canals, ranging from 25° to 30°, were prepared with ProTaper Next using X2 to full working length and were filled with calcium hydroxide. Teeth also were randomly divided into four groups: group 1 (n = 8)- Erbium: Yttrium-Aluminum-Garnet (Er:YAG) laser; group 2 (n = 8)-EndoActivator; group 3 (n = 8)-EndoVac; and a control group (n = 6)-negative control with no calcium hydroxide. Microcomputed tomography was used to evaluate the residual amount of filling material. Statistical analysis was performed using IBM SPSS Statistics 26, with a significance level of 0.05. Descriptive statistics, student t test, and Chi-square test were applied for data analysis. The greatest amount of residual calcium hydroxide was observed in the samples with EndoVac irrigation (0.515 mm3), followed by EndoActivator (0.381 mm3) and Er:YAG laser (0.121 mm3). However, no statistically significant difference was observed between the groups. The greatest residual amount was observed in the apical third (0.419 mm3), followed by the middle (0.050 mm3) and the coronal (0.015 mm3). No statistically significant differences were observed in the efficacy of the tested techniques for removing calcium hydroxide from curved root canals, whereas a significant difference was observed in the distribution of residual material depending on the technique used. The removal of the calcium hydroxide was more effective in the coronal and middle third of the canal. The greatest residual material was found in the apical portion of the root canal.

Effectiveness of calcium hydroxide removal with irrigation techniques using ProTaper and ultrasonic activation: an in vitro study

Background: Residual calcium hydroxide might adversely affect the outcome of endodontic treatment results. Calcium hydroxide affect the adhesion of endodontic sealers to the canal walls and interfere with sealing ability of endodontic sealers. To remove this intracanal medicament, there are various irrigation techniques have developed. The aim of this study was to evaluate the effectiveness of different techniques in removing calcium hydroxide from the root canal. Materials and methods: Thirty extracted single-rooted mandibular premolar were instrumented and filled with calcium hydroxide and divided into three groups (n = 10/group). After 7 days, calcium hydroxide was removed. All root canals were received 2.5% NaOCl, followed by 17% EDTA and a final flush with 2.5% NaOCl. In group I, no additional agitation of the irrigant was performed. In group II, agitation was done for 20 s between irrigants with a size of F2 ProTaper rotary file. In group III, an ultrasonic activation was delivered for 20 s between irrigants. Finally, the roots were grooved longitudinally and split in two halves. Selected half of each tooth was observed under a stereomicroscope at 30x magnification. Results: In groups needle irrigation and ProTaper technique, score of residual calcium hydroxide in apical third is higher than cervical and middle thirds (p < 0.05). Needle groups demonstrated the significantly higher score of residual calcium hydroxide than ProTaper and ultrasonic groups (p < 0.05). Conclusion: None of irrigation techniques could remove all calcium hydroxide completely. Ultrasonic irrigation and ProTaper irrigation was more effective in removing calcium hydroxide than needle irrigation. Key words: calcium hydroxide, irrigation solution, ultrasonic irrigation.

CREATION OF A POZZOLANIC MATERIAL FROM WASTE CALCIUM HYDROXIDE AND RECYCLED GLASS POWDER

The use of consumer and industrial waste as supplementary cementitious materials is one solution to the development of sustainable Portland cement. This research studied the partial replacement of cement with a pozzolanic mixture of recycled soda-lime glass powder (GP) and waste calcium hydroxide (CH). The optimal weight ratio of CH and GP was selected from five ratios between 30/70 to 70/30 (CH/GP), using thermal gravimetric analysis and X-ray diffraction. It was found that CH deficient ratios contained residual glass powder, while CH rich ratios contained residual calcium hydroxide and had undesirable carbonation of the CH. The 60/40 pozzolan was selected due to the large amount of calcium silicate hydrate (C-S-H) gel that was formed, the absence of residual GP and a minimum of excess CH. Portland cement (PC) specimens with 20 to 40 wt.% replacement by the 60/40 pozzolan were characterized for porosity and compressive strength at aging times from 3 to 28 days. The PC with 20 to 40 wt.% pozzolan had slightly increased porosity due to an increased amount of unreacted water from the batch. The porosity decreased with increased aging time. The PC with 30 wt.% pozzolan had a compressive strength equal to the reference PC, but only after 7 days or longer of aging. This was likely due to the slower reaction rate of the pozzolan. The 60/40 CH/GP pozzolan appears to be a viable partial replacement for PC when used at 30 wt.%.

Fracture properties of steel fibre reinforced high-volume fly ash self-compacting concrete

This paper presents an experimental investigation on the fracture mechanical properties of steel fibre-reinforced high-volume fly ash self-compacting concrete (HFSCC). Specifically, self-compacting concrete (SCC) of various toughness was designed at desired steel fibre volume fractions of 0, 0.25 v%, 0.50 v%, 0.75 v% and 1.00 v% by volume and fly ash contents of 40 wt%, 50 wt%, 60 wt% and 70 wt% by mass. The fracture mechanical properties of HFSCC (cured for one year) were studied by a three-point bending beam test. The influence of fly ash and steel fibre content on fracture parameters was systematically discussed. The research indicated that the fracture mechanical properties of HFSCC with different fly ash percentage were improved by adding steel fibres. The fullness of the force (F)-crack mouth opening displacement (CMOD) curves gradually increased with the steel fibre volume fraction (Vf). The peak load (Fp), peak CMOD (CMODP), fracture toughness (KIC) and fracture energy (GF) of the fracture parameters linearly increased with Vf. Furthermore, the correlation between them was analysed numerically. The slope of the fitting line increased with increasing fly ash content, indicating that high-volume fly ash was more conducive to improving the fracture mechanics of SCC after long-term ageing. After the hydration reaction, residual calcium hydroxide was observed only in the cross-sectional image of HFSCC-70, it helped to improve the fracture mechanical properties of HFSCC.

Influence of access cavity design on calcium hydroxide removal using different cleaning protocols: a confocal laser scanning microscopy study.

The purpose of this study was to evaluate the influence of endodontic access cavities design on the removal of calcium hydroxide medication of the apical third of mandibular incisor root canal walls and dentinal tubules with different cleaning protocols: EDDY sonic activation, Er,Cr:YSGG laser-activated irrigation, or conventional irrigation with IrriFlex. Seventy-eight extracted human mandibular incisors were assigned to 6 experimental groups (n = 13) according to the endodontic access cavity and cleaning protocol for calcium hydroxide removal: traditional access cavity (TradAC)/EDDY; ultraconservative access cavity performed in the incisal edge (UltraAC.Inc)/EDDY; TradAC/Er,Cr:YSGG; UltraAC.Inc/Er,Cr:YSGG; TradAC/IrriFlex; or UltraAC.Inc/IrriFlex. Confocal laser scanning microscopy images were used to measure the non-penetration percentage, maximum residual calcium hydroxide penetration depth, and penetration area at 2 and 4 mm from the apex. Data were statistically analyzed using Shapiro-Wilk and WRS2 package for 2-way comparison of non-normally distributed parameters (depth of penetration, area of penetration, and percentage of non-penetration) according to cavity and cleaning protocol with the significance level set at 5%. The effect of cavity and cleaning protocol interactions on penetration depth, penetration area and non-penetration percentage was not found statistically significant at 2 and 4 mm levels (p > 0.05). The present study demonstrated that TradAC or UltraAC.Inc preparations with different cleaning protocols in extracted mandibular incisors did not influence the remaining calcium hydroxide at 2 and 4 mm from the apex.

Farklı irrigasyon tekniklerinin kalsiyum hidroksit uzaklaştırma etkinliğinin Bilgisayarlı Sıvı Filtrasyon methodu kullanılarak mikrosızıntılarının değerlendirilmesi

Aim: To compare the efficiency of sonic irrigation, passive ultrasonic irrigation, and conventional syringe irrigation (CI) in removing pure and injectable calcium hydroxide (CH) from the root canals of mandibular second premolars by measuring the probable microleakage of residual CH particles in root canal obturation using computerized liquid filtration (CLF). Materials and Methods: Eighty instrumented mandibular second premolars were categorized into three experimental groups (n = 20 each) based on the irrigation method used for removing CH and a control group (n = 20) in which CH was not used. Each experimental group was divided into two equal groups (pure and injectable CH). After 1 week, CH was removed from the root canals, and the teeth were obturated. CLF measurements were performed 1 week after obturation. Nonparametric variables between two groups were compared using the Mann-Whitney U test, and the Kruskal-Wallis test was used to compare more than two groups. The significance level was set at p < 0.05. Results: All experimental groups showed higher leakage values than the control group. The highest leakage values were evident in the CI group, and the lowest leakage values were found in the sonic (EDDY) irrigation group. No significant differences were detected among the different forms of CH. Conclusions: None of the analyzed techniques could completely remove CH from root canals, resulting in higher leakage values. Sonic irrigation with EDDY was the best in removing CH from root canals.

An In Vitro Comparison of Different Irrigants Used for the Removal of Calcium Hydroxide from Root Canal Walls

Aim: This study was aimed to appraise the effectiveness of different activated irrigants in removing the inter appointment calcium hydroxide dressing from the walls of root canal system. Methodology: Forty single rooted premolars were collected and instrumented using ProTaper rotary files, followed by the application of calcium hydroxide dressing. After incubating for a week, the teeth were randomly allocated into four experimental groups (n= 10), based upon the irrigant used: saline, sodium hypochlorite, 70% ethanol, 10% citric acid. The sample teeth were then cleaved buccolingually and the amount of residual calcium hydroxide on the walls of root canal was assessed under a stereomicroscope with 40x magnification. Kruskal-Wallis test and Dunn’s post hoc test compared the groups and the level of significance was set at p<0.05. Results: None of the irrigants could completely get rid of calcium hydroxide from the root canals. Irrigation with 10% citric acid produced significantly cleaner canal walls, followed by 70% ethanol. There was no significant statistical difference between the saline and sodium hypochlorite groups. Conclusion: The present study denotes that citric acid and ethanol enhanced the cleansing of the root canal walls, leaving least amount of residual calcium hydroxide when compared to the commonly used irrigants such as saline and sodium hypochlorite

The effectiveness of ethylenediaminetetraacetic, etidronic, and peracetic acids activated with ultrasonics or diode laser on calcium hydroxide removal from root canal walls.

To assess the efficiency of ethylenediaminetetraacetic acid (EDTA), etidronic (HEBP), and peracetic (PAA) acids agitated with ultrasonic energy or diode laser on removing calcium hydroxide (CH) dressings from root canal walls. Single root canals of eighty extracted human teeth were chemomechanically instrumented and filled with CH. Sixty teeth were divided into six experimental groups (n = 10) according to the applied irrigation regimens for the removal of CH: Group 1: 5.25% NaOCl-17% EDTA, Passive ultrasonic irrigation (PUI); Group 2: 5.25% NaOCl + 9% HEBP, PUI; Group 3: 5.25% NaOCl-2% PAA, PUI; Group 4: 5.25% NaOCl-17% EDTA, Diode laser-activated irrigation (LAI); Group 5: 5.25% NaOCl + 9% HEBP, LAI; Group 6: 5.25% NaOCl-2% PAA, LAI. The other 20 teeth were served as negative (n = 10) and positive controls (n = 10). The residuary amount of CH was scored in coronal, middle, and apical thirds of the root canals by using scanning electron microscope. The data were statistically analyzed using Kruskal-Wallis H with Bonferroni adjusted Mann-Whitney U test with a significance level of 0.05. Etidronic acid activated with ultrasonics or diode laser removed the highest amount of CH from the middle third of root canals, compared to the other irrigation regimens (P < 0.001). Although the residual CH scores of PAA-PUI, PAA-LAI, and EDTA-PUI, EDTA-LAI groups were not statistically different from each other (P > 0.05), lower amount of CH was observed in the PAA-PUI and PAA-LAI groups. Use of etidronic acid activated with ultrasonics or diode laser can be an appropriate irrigation regimen for CH removal from root canal system.

EFFECTIVENESS OF ULTRASONIC IRRIGATION ON CALCIUM HYDROXIDE REMOVAL WITH DIFFERENT SOLUTIONS: AN IN VITRO STUDY

Background: Calcium hydroxide has been widely used in endodontics as an intracanal medicament. Before obturation, calcium hydroxide, an intracanal medicament should be completely removed from the root canal system sinceresidual calcium hydroxide might adversely affect the outcome of endodontic treatment results. Various irrigation techniques to remove this intracanal medicament have developed. The aim of this in vitro study was to evaluate the effectiveness in removing calcium hydroxide from the root canal, with or without using ultrasonic activation. Materials and methods: Sixty extracted single-rooted mandibular premolar were instrumented using ProTaper rotary instruments, filled with calcium hydroxide and divided into six groups (n=10/group). Subsequently, calcium hydroxide was removed by six different protocols. Group I, II, II were flushed using 2.5% NaOCl, 17% EDTA, 10% citric acid, respectively. Group IV, V, VI were flushed using the same irrigants respectively with ultrasonic activation. Finally, the roots were grooved longitudinally and split in two halves. Selected half of each tooth was observed under a stereomicroscope at 30x magnification to assess the residual calcium hydroxide score. Results: NaOCl 2,5% demonstrated the significantly higher score of residual calcium hydroxide than EDTA 17% and citric acid 10% (p&lt;0.05). Groups combined with ultrasonic irrigation was significant lower than the others (p&lt;0.05). Conclusion: None of the six techniques could remove all calcium hydroxide completely. Ultrasonic irrigation was more effective in removing calcium hydroxide than syringe delivery. Key words: calcium hydroxide, irrigation solution, ultrasonic irrigation

Efficacy of Laser-Activated Irrigation and Conventional Techniques in Calcium Hydroxide Removal from Simulated Internal Resorption Cavities: Micro-CT Study.

Objective: This study aimed to evaluate the effectiveness of different irrigant-activation techniques for eliminating calcium hydroxide from an internal root canal resorption cavity by using microcomputed tomography (micro-CT). Background: Several techniques and irrigants are inadequate for the complete removal of calcium hydroxide from an internal root resorption cavity. Recently, a few studies have investigated the effectiveness of various methods, but there has been no micro-CT study that compares the effectiveness of photon-induced photoacoustic streaming (PIPS) and shock wave enhanced emission photoacoustic streaming (SWEEPS) techniques. Methods: Seventy single-canal mandibular premolar teeth were selected and divided into seven groups (n = 10) according to the techniques to be used: syringe irrigation (SI), passive ultrasonic irrigation (PUI), EndoActivator (EA), XP-Endo finisher file (XP), Er,Cr:YSGG laser-activated irrigation, PIPS, and SWEEPS. The root canals were instrumented using a rotary system and divided vertically. Internal resorption cavities were created and standardized through diamond burs. Calcium hydroxide was placed into the root canal space. All specimens were evaluated using micro-CT in two different periods. The initial and residual calcium hydroxide volumes in the simulated cavities were calculated. Data were analyzed using a Kruskal-Wallis H test. Results: SWEEPS and PIPS were significantly more effective than EA, Er,Cr:YSGG, PUI, XP, and SI (p < 0.05). There was no significant difference between the SWEEPS and PIPS groups (p > 0.05). SI and XP showed the least effective activity (p < 0.05). Conclusions: The SWEEPS and PIPS techniques were superior to the EA, Er,Cr:YSGG, PUI, XP, and SI techniques. None of the techniques used entirely removed the calcium hydroxide from the resorption cavities.

Efficacy of Passive Ultrasonic Activation in Removing Calcium Hydroxide from Simulated Internal Resorption Cavities at Different Root Regions.

The aim of this study was to evaluate the effect of passive ultrasonic activation on calcium hydroxide removal from simulated internal root resorption (IRR) cavities at different root levels. Sixty mandibular canines were prepared and divided into 3 groups to create IRR cavities at apical, middle, coronal root levels. The cavities filled with calcium hydroxide (CH). Specimens were divided into two subgroups according to the technique used for CH removal: Passive ultrasonic activation (PUA), Classic syringe irrigation (CSI). The cavities were photographed with a stereomicroscope, and percentage of remaining CH was measured using digital image analysis software (Image J). Statistical analysis was performed with two-way ANOVA and post-hoc Duncan tests. PUA removed significantly more CH at apical and middle levels. (p < 0.05) There was no significant difference between PUA and CSI at coronal level. (p > 0.05) In PUA group, the amount of residual CH was the highest at coronal level. (p < 0.05) In CSI group, the amount of residual CH was the highest at apical level. (p < 0.05). None of the tested technique was able to completely remove CH from the simulated IRR cavities. CH was removed better with PUA than CSI at middle and apical root levels. For both techniques, the best results were obtained at middle root level.

Experimental investigations on the durability and degradation mechanism of cast-in-situ recycled aggregate concrete under chemical sulfate attack

With the increase of construction solid waste (CSW) in China's urbanization construction, many ecological and environmental problems have been raised. Recycling and reusing of construction waste is conductive to reducing pollution, carbon emissions and conserving resources. Cast-in-situ concrete structures have been widely used in foundation engineering, application of cast-in-situ recycled aggregate concrete (CRAC) has broad application prospect. This paper investigated the mechanical properties and durability of cast-in-situ recycled aggregate concrete under chemical sulfate attack. Cylinder specimens were casted with four recycled concrete aggregate (RCA) replacements of 0%, 30%, 50% and 100%, and immersed into the exposures of tap water, single sulfate solution and chloride-sulfate mixed solution, respectively. Visual inspection and indicators of sulfate concentration, mass and diameter variation, compressive strength were monitored in the exposure of 52 weeks. The results exhibited that RCA replacement has a significant impact on the mechanical properties and sulfate resistance of CRAC, and the existence of chloride can significantly hinder the sulfate diffusion and delays the deterioration of CRAC. Microscopic evidence also indicated that the dissolving of calcium hydroxide and formation of ettringite resulted in the CRAC degradation. Most importantly, RCA and ITZ can avoid serious chemical attack due to less residual calcium hydroxide existed, while ITZ with a higher porosity can further provide the diffusion path for the sulfate.

Velocity and wall shear stress of 18% EDTA irrigation solution flow in the removal of Ca(OH)2 with computational fluid dynamic analysis

Introduction: Ethylene Diamine Tetra Acetic Acid (EDTA) 18% irrigation solution is one of the chelating agents that able to remove calcium hydroxide (Ca(OH)2) from the root canal wall. Failure of root canal treatment can be caused by the presence of residual calcium hydroxide in the root canal wall, thus blocking the bond between the medication and root canal filling material with the root canal wall. This study was aimed to observe the EDTA 18% flow in removing the Ca(OH)2 using CFD analysis. Methods: This research was descriptive. Cleanliness of the root canal wall from Ca(OH)2 medicament using EDTA 18% irrigation was analysed using the CFD method with test specimens in the form of resin blocks made according to the characteristics of the root canal. The irrigation needle used was side-vented with a position of 3 mm from the apical tooth. Stage analysis of root canal geometry was performed using Computational Fluid Dynamics (CFD) analysis to observe the characteristics of irrigation solutions in root canals in 3D. Results: The streamlined characteristics of EDTA 18% irrigation solution showed a unique behaviour due to the features of the side-vent shaped irrigation needle. Irrigation flow in the crown area of the inlet (side-vented irrigation needle) showed low velocity so that the fluid flow when exiting the inlet was more towards the apical than the outlet (root canal orifice). Conclusion: Velocity and wall shear stress of EDTA 18% showed the results validation conformity between experimental and CFD, that the maximum velocity of EDTA 18% is 19 ms-1 and EDTA 18% wall shear stress is 1.56 KPa for calcium hydroxide removal observed from the CFD study. Keywords: Computational fluid dynamics, EDTA 18%, calcium hydroxide (Ca(OH)2), velocity, wall shear stress

Efficacy of XP-Endo finisher in removal of calcium hydroxide from root canal system: A systematic review

Calcium hydroxide (CH) is widely used as an intracanal medicament between appointments to increase the number of canals free from bacteria. However, the remnant CH hinders the penetration of disinfectants and sealers into dentinal tubules and compromises the seal of the canal filling. Therefore, residual CH must be removed before permanent root canal obturation is completed. To analyze the efficacy of XP-endo finisher on the removal of CH medicament from root canal system. English language articles were retrieved from electronic biomedical journal databases. PubMed, Google Scholar, and ResearchGate were used to complete the search for all full-text articles available. The search was done till August 31, 2018. The last data search was conducted on September 1, 2018. All articles that were published in English were included. Only those articles that were published between January 1, 2011, and August 31, 2018, using XP-endo finisher were selected. The efficacy of XP-endo finisher on removal of CH medicament from root canal system. Total of 17 articles was identified through electronic database searching. After duplicate removal, and full-text reading, six articles qualified for qualitative synthesis in this systematic review. XP-endo finisher is proven to be more efficient in removing the CH medicament from root canal system.

Efficacy of Laser-Activated Irrigants in Calcium Hydroxide Removal from the Artificial Grooves in Root Canals: An Ex Vivo Study.

The aim of this study was to investigate the efficacy of an erbium chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser with different irrigation solutions [sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA), QMix 2in1, and peracetic acid] in removing calcium hydroxide (CH) from artificial grooves created in root canals. CH has to be removed totally before the root canal filling. Any CH residue on the dentin walls may affect the dentinal bond strength and the penetration of sealers into the dentin tubules, and may increase apical leakage. In addition, such a remnant could react chemically with sealers and, possibly, influence physical properties. Therefore, complete removal of CH placed inside the root canals is recommended, using various products and techniques. The root canals of 160 extracted single-rooted mandibular premolars were prepared with ProTaper Universal rotary instruments up to size F4. The roots were split longitudinally along the length of the instrumented canals, and a standardized groove was prepared in the apical part of one segment. CH powder mixed with distilled water was placed into the grooves, and the root halves were then reassembled. The roots were randomly divided into two main groups according to the selected irrigation techniques (needle and laser activation) and then each main group was divided into four subgroups according to the final irrigation (NaOCl, EDTA, QMix 2in1, and peracetic acid) protocols used. After irrigation, the roots were disassembled and digital images were taken using a stereomicroscope. Measurements of residual CH were performed as percentages of the overall groove surface area with image analysis software. The data obtained were analyzed using one way analysis of variance and Tukey's honest significant difference tests. Statistical significance was set at p < 0.05. Significantly less residual CH was obtained in the laser-activated groups than in the needle-irrigated groups (p < 0.05). According to both main groups' data, NaOCl left significantly more CH than the other groups (p < 0.05). However, there was no significant difference among the EDTA, QMix 2in1, and peracetic acid groups. None of the techniques removed the CH dressing completely. Laser-activated irrigation was significantly more effective than needle irrigation.

The effect of residual calcium hydroxide on the accuracy of a contemporary electronic apex locator

The effect of residual calcium hydroxide on the accuracy of a contemporary electronic apex locator