Comparison of Dentin Caries Remineralization with Four Bioactive Cements.

The treatment of deep carious lesions involves the use of ion-releasing agents to seal the lesions. These agents release minerals, leading to the remineralization of the remaining demineralized dentin. This study aimed to compare the dentin caries remineralization with bioactive cements. 60 Dentin blocks were prepared from the dentin of human third molars. Artificial carious lesions were induced on the blocks with pH cycling. The samples were divided into five groups (n=12). Dycal, Oxford ActiveCal PC, Biodentine, and ACTIVA BioACTIVE were applied using a mold. One group did not receive any cement. The samples were stored in remineralization solution for 30 days. The cement was removed using a #15 blade, and the dentin surface was evaluated using Energydispersive X-ray Spectroscopy and X-ray Diffraction. One-way ANOVA did not show a significant difference in the weight percentages of calcium and phosphorus and the calcium-to-phosphorus ratios between the groups. The highest and the lowest weight percentages of calcium and phosphorus were observed in Biodentine and control groups, respectively. There were no significant differences in the remineralization properties of bioactive cements. Hydroxyapatite crystals were not formed in any of the adjacent dentin using these cements.

PRIASE 2021 guidelines for reporting animal studies in Endodontology: explanation and elaboration.

Laws and ethics require that before conducting human clinical trials, a new material, device or drug may have to undergo testing in animals in order to minimize health risks to humans, unless suitable supporting grandfather data already exist. The Preferred Reporting Items for Animal Studies in Endodontology (PRIASE) 2021 guidelines were developed exclusively for the specialty of Endodontology by integrating and adapting the ARRIVE (Animals in Research: Reporting In Vivo Experiments) guidelines and the Clinical and Laboratory Images in Publications (CLIP) principles using a validated consensus-based methodology. Implementation of the PRIASE 2021 guidelines will reduce potential sources of bias and thus improve the quality, accuracy, reproducibility, completeness and transparency of reports describing animal studies in Endodontology. The PRIASE 2021 guidelines consist of a checklist with 11 domains and 43 individual items and a flowchart. The aim of the current document is to provide an explanation for each item in the PRIASE 2021 checklist and flowchart and is supplemented with examples from the literature in order for readers to understand their significance and to provide usage guidance. A link to the PRIASE 2021 explanation and elaboration document and PRIASE 2021 checklist and flowchart is available on the Preferred Reporting Items for study Designs in Endodontology (PRIDE) website (http://pride-endodonticguidelines.org/priase/).

PRIASE 2021 guidelines for reporting animal studies in Endodontology: a consensus-based development.

Animal testing is crucial in situations when research on humans is not allowed because of unknown health risks and ethical concerns. The current project aims to develop reporting guidelines exclusively for animal studies in Endodontology, using an established consensus-based methodology. The guidelines have been named: Preferred Reporting Items for Animal Studies in Endodontology (PRIASE) 2021. Nine individuals (PD, VN, AK, PM, MN, JF, EP, JJ and SJ), including the project leaders (PD, VN) formed a steering committee. The steering committee developed a novel checklist by adapting and integrating their animal testing and peer review experience with the Animals in Research: Reporting In Vivo Experiments (ARRIVE) guidelines and also the Clinical and Laboratory Images in Publications (CLIP) principles. A PRIASE Delphi Group (PDG) and PRIASE Online Meeting Group (POMG) were also formed. Thirty-one PDG members participated in the online Delphi process and achieved consensus on the checklist items and flowchart that were used to formulate the PRIASE guidelines. The novel PRIASE 2021 guidelines were discussed with the POMG on 9 September 2020 via a Zoom online video call attended by 21 individuals from across the globe and seven steering committee members. Following the discussions, the guidelines were modified and then piloted by several authors whilst writing a manuscript involving research on animals. The PRIASE 2021 guidelines are a checklist consisting of 11 domains and 43 individual items together with a flowchart. The PRIASE 2021 guidelines are focused on improving the methodological principles, reproducibility and quality of animal studies in order to enhance their reliability as well as repeatability to estimate the effects of endodontic treatments and usefulness for guiding future clinical studies on humans.

Altmetric analysis of the contemporary scientific literature in Endodontology.

AIM: To analyse and visualize the knowledge structure of scientific articles in the field of Endodontology with high altmetric attention scores to discover hot topics, active researchers and the journals involved. METHODOLOGY: On 5 June 2019, the altmetric database (Altmetric LLP, London, UK) was searched using the titles of 11 endodontic journals. Bibliometric data from endodontic articles and journals with an altmetric score >5 (top 5%) were retrieved from PubMed and analysed using the VOSviewer. Science mapping of articles with an altmetric score >5 at two levels was created: author keywords co-occurrence and co-authorship network analysis. RESULTS: Of the 2197 articles in the field of Endodontology identified with altmetrics, 192 had altmetric scores >5 (top 5%). Considering the total mentions amongst all altmetric resources, the Journal of Endodontics had the highest rank followed by the International Endodontic Journal and Australian Endodontic Journal. Twitter was the most popular altmetric data resource followed by patents and Facebook. Meta-analysis, systematic review and pulpitis were the hot topics. At the author level, Dummer P.M.H had the greatest influence on the network. There was no significant correlation between altmetric score and citations count (P > 0.05). Mendeley mentions correlated with citations (P < 0.05). CONCLUSIONS: Overall, the altmetric scores of topics within Endodontology were low, possibly due to the specific and specialized nature of the specialty, as well as the difficulty members of the public probably have in understanding endodontic research. Journals and researchers with a focus on Endodontology would have more influence if they were to set-up their own social media profiles and thus enhance their visibility and social impact by immediately sharing research findings and communicating with their network and audience.

Is articaine more effective than lidocaine in patients with irreversible pulpitis? An umbrella review.

BACKGROUND: Pain management can be challenging during root canal treatment of teeth with irreversible pulpitis. AIM: To identify whether articaine or lidocaine is the most appropriate local anaesthetic solution for teeth with irreversible pulpitis undergoing root canal treatment. DATA SOURCE: The protocol of this umbrella review is registered in the PROSPERO database (CRD42019137624). PubMed, EBSCHO host and Scopus databases were searched until June 2019. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS: Systematic reviews published in English comparing the effectiveness of local anaesthesia following administration of articaine or lidocaine in patients undergoing root canal treatment of teeth diagnosed with irreversible pulpitis were included. Two independent reviewers selected the studies and carried out the data extraction and the appraisal of the included reviews. Disagreements were resolved in consultation with a third reviewer. STUDY APPRAISAL AND SYNTHESIS METHODS: The quality of the included reviews was appraised by two independent reviewers using the AMSTAR tool (a measurement tool to assess systematic reviews). Each of the 11 AMSTAR items was given a score of 1 if the specific criterion was met, or 0 if the criterion was not met or the information was unclear. RESULTS: Five systematic reviews with meta-analyses were included. The AMSTAR score for the reviews ranged from 8 to 11, out of a maximum score of 11, and all reviews were categorized as 'high' quality. Two reviews scored 0 for item 8 in AMSTAR because the scientific quality of the clinical trials included in these reviews was not used in the formulation of the conclusions. LIMITATIONS: Systematic reviews published only in the English language were included. Only a small number of studies were available to assess pain intensity during the injection phase, the time until the onset of anaesthesia and the occurrence of adverse events. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS: Articaine is more effective than lidocaine for local anaesthesia of teeth with irreversible pulpitis undergoing root canal treatment. There is limited evidence that injection of articaine is less painful, has more rapid onset and has fewer adverse events compared with lidocaine.

The effect of operator-induced variability on the physical properties of ProRoot MTA.

AIMS: The aim of this study was to compare the influence of operators on the microhardness and compressive strength of mineral trioxide aggregate (MTA). MATERIALS AND METHODS: Forty dental specialists were asked to prepare a series of MTA samples. The tested material was ProRoot MTA (DentsplyMaillefer, Switzerland). Each participant prepared one sample to a consistency they considered acceptable for use in practice (improvised group) and another one according to the manufacturer's recommended water-to-powder (WP) ratio (pre-weighed group). The samples were incubated at 37°C and 95% humidity for 4 days. Parameters evaluated in this study were microhardness and compressive strength. RESULTS: Operators mixed MTA samples with varying WP ratios. However, there was no significant difference between the microhardness and compressive strength values of MTA samples between the improvised, the pre-weighed and the control groups. MTA was mixed in a thicker consistency than the manufacturers recommended ratio (0.33) by 62.5% of the operators. CONCLUSION: According to the results of this study, even though the WP ratios that were utilized in the clinical setting vary, microhardness and compressive strength values of MTA was not significantly affected.

Preferred Reporting Items for Animal Studies in Endodontology: a development protocol.

The regulated use of animals in endodontic research is often necessary to investigate the biological mechanisms of endodontic diseases and to measure the preclinical efficacy, biocompatibility, toxicology and safety of new treatments, biomaterials, sealers, drugs, disinfectants, irrigants, devices and instruments. Animal testing is most crucial in situations when research on humans is not ethical, practical or has unknown health risks. Currently, there is a wide variability in the quality of manuscripts that report the results of animal studies. Towards the goal of improving the quality of publications, guidelines for preventing disability, pain, and suffering to animals, and enhanced reporting requirements for animal research have been developed. These guidelines are referred to as Animals in Research: Reporting In Vivo Experiments (ARRIVE). Henceforth, causing any form of animal suffering for research purposes is not acceptable and cannot be justified under any circumstances. The present report describes a protocol for the development of welfare and reporting guidelines for animal studies conducted in the specialty of Endodontology: the Preferred Reporting Items for Animal Studies in Endodontology (PRIASE) guidelines. The PRIASE guidelines will be developed by adapting and modifying the ARRIVE guidelines and the Clinical and Laboratory Images in Publication (CLIP) principles. The development of the new PRIASE guidelines will include a five-step consensus process. An initial draft of the PRIASE guidelines will be developed by a steering committee. Each item in the draft guidelines will then be evaluated by members of a PRIASE Delphi Group (PDG) for its clarity using a dichotomous scale (yes or no) and suitability for its inclusion using a 9-point Likert scale. The online surveys will continue until each item achieves this standard, and a set of items are agreed for further analysis by a PRIASE Face-to-face Consensus Meeting Group (PFCMG). Following the consensus meeting, the steering committee will finalize and confirm the PRIASE guidelines taking into account the responses and comments of the PFCMG. The PRIASE guidelines will be published and disseminated internationally and updated periodically based on feedback from stakeholders.

Microstructure and chemical analysis of four calcium silicate-based cements in different environmental conditions.

OBJECTIVE: The objective of this study was to analyze the microstructure and crystalline structures of ProRoot MTA, Biodentine, CEM Cement, and Retro MTA when exposed to phosphate-buffered saline, butyric acid, and blood. METHODS AND MATERIALS: Mixed samples of ProRoot MTA, Biodentine, CEM Cement, and Retro MTA were exposed to either phosphate-buffered saline, butyric acid, or blood. Scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopic (EDX) evaluations were conducted of specimens. X-ray diffraction (XRD) analysis was also performed for both hydrated and powder forms of evaluated calcium silicate cements. RESULTS: The peak of tricalcium silicate and dicalcium silicate detected in all hydrated cements was smaller than that seen in their unhydrated powders. The peak of calcium hydroxide (Ca(OH)2) in blood- and acid-exposed ProRoot MTA, CEM Cement, and Retro MTA specimens were smaller than that of specimens exposed to PBS. The peak of Ca(OH)2 seen in Biodentine™ specimens exposed to blood was similar to that of PBS-exposed specimens. On the other hand, those exposed to acid exhibited smaller peaks of Ca(OH)2. CONCLUSION: Exposure to blood or acidic pH decreased Ca(OH)2 crystalline formation in ProRoot MTA, CEM Cement and Retro MTA. However, a decrease in Ca(OH)2 was only seen when Biodentine™ exposed to acid. CLINICAL RELEVANCE: The formation of Ca(OH)2 which influences the biological properties of calcium silicate cements was impaired by blood and acid exposures in ProRoot MTA, CEM Cement, and Retro MTA; however, in the case of Biodentine, only exposure to acid had this detrimental effect.

Histologic tissue response to furcation perforation repair using mineral trioxide aggregate or dental pulp stem cells loaded onto treated dentin matrix or tricalcium phosphate.

OBJECTIVES: The aim of this study is to compare the effect of treated dentine matrix (TDM) and tricalcium phosphate (TCP) scaffolds on odontogenic differentiation and mineralization of dental pulp stem cells (DPSCs) in furcation perforations created in the pulp chamber floor of premolar teeth in dogs. MATERIAL AND METHODS: DPSCs were isolated and cultured from the dental pulp of the maxillary left second and third premolars of dogs. The DPSCs were loaded on TCP (SC+TCP) and TDM (SC+TDM) scaffolds and inserted into intentionally perforated pulp chamber floors of premolars in dogs; six teeth were used for each group. Three more groups of six specimens were created, and mineral trioxide aggregate (MTA), TDM, and TCP were inserted into the perforations to act as controls. An intact premolar and no treatment in the perforation site were used as positive and negative controls respectively. After 3 months, the animals were sacrificed and the type of inflammation, presence of dentine, continuation and type of cementum, type of connective tissue, and presence of foreign body reaction were evaluated, and significant differences were between groups determined using the Fisher's exact test. The evaluation of the amount of inflammation and the percentage of new bone formation was evaluated using the Mann-Whitney U test. RESULTS: The negative control group was associated with severe inflammation and granulation tissue formation. In the positive control group, intact periodontal tissues and no inflammation were observed. Dentine bridge formation was not seen in specimens of any group. The specimens in the SC+TDM group were associated with significantly more bone formation than other groups (P < 0.001). The amount of inflammation was less than 10 % in specimens of all groups with the exception of three specimens in the TCP group that were categorized as 10-30 %. Chronic inflammation without foreign body reactions was the major pattern of inflammation in groups. Formation of cementum with a cellular and continuous appearance was seen in all specimens. CONCLUSIONS: SC+TDM was associated with significantly more bone formation when used to repair uninfected furcation perforations in the premolar teeth of dogs. CLINICAL RELEVANCE: Application of TDM as a biological scaffold in combination with DPSCs may offer an advantage during the repair of root perforation defects.

Effect of bismuth oxide on white mineral trioxide aggregate: chemical characterization and physical properties.

AIM: To assess the effect of bismuth oxide (Bi2 O3 ) on the chemical characterization and physical properties of White mineral trioxide aggregate (MTA) Angelus. METHODOLOGY: Commercially available White MTA Angelus and White MTA Angelus without Bi2 O3 provided by the manufacturer especially for this study were subjected to the following tests: Rietveld X-ray diffraction analysis (XRD), energy-dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), compressive strength, Vickers microhardness test and setting time. Chemical analysis data were reported descriptively, and physical properties were expressed as means and standard deviations. Data were analysed using Student's t-test and Mann-Whitney U test (P = 0.05). RESULTS: Calcium silicate peaks were reduced in the diffractograms of both hydrated materials. Bismuth particles were found on the surface of White MTA Angelus, and a greater amount of particles characterized as calcium hydroxide was observed by visual examination on White MTA without Bi2 O3 . The material without Bi2 O3 had the shortest final setting time (38.33 min, P = 0.002), the highest Vickers microhardness mean value (72.35 MPa, P = 0.000) and similar compressive strength results (P = 0.329) when compared with the commercially available White MTA Angelus containing Bi2 O3 . CONCLUSION: The lack of Bi2 O3 was associated with an increase in Vickers microhardness, a reduction in final setting time, absence of Bi2 O3 peaks in diffractograms, as well as a large amount of calcium and a morphology characteristic of calcium hydroxide in EDX/SEM analysis.

Unintentional extrusion of mineral trioxide aggregate: a report of three cases.

AIM: Mineral trioxide aggregate (MTA) is the material of choice for apical barrier techniques during root canal treatment of teeth with open apices. However, the precise control of MTA during the placement of an apical plug is challenging. This article describes the outcomes of unintentional extrusion of MTA into the periradicular tissue during apical barrier treatment in three cases. SUMMARY: Three cases of maxillary central incisors in adult patients with open apices were referred for treatment. After conventional access and canal preparation, MTA was placed into the apical portion of the root canals to act as an apical barrier/plug. A large increment of MTA was extruded in all cases. In Case 1, after a 4-year follow-up, the extruded MTA had resorbed and the periradicular lesion had healed. In Cases 2 and 3, after follow-up, the patients remained symptomatic and were scheduled for periradicular surgery. In Case 2, soft unset particles of MTA were present in the lesion and were curetted. In Case 3, the extruded MTA had set hard but was sandwiched between the oral mucosa and bone; its removal relieved the pain experienced on buccal palpation. KEY LEARNING POINTS: Extruded MTA may not harden and may be associated with ongoing periapical irritation; Extruded set MTA when encapsulated in the mucosa and not surrounded by bony matrix may act as a mechanical irritant on palpation; Mineral trioxide aggregate should be confined to the root canal system; Teeth where MTA has been extruded beyond the foramen should be followed-up to monitor the outcome.

Evaluation of three imaging techniques for the detection of vertical root fractures in the absence and presence of gutta-percha root fillings.

AIM: To compare the accuracy of digital radiography (DR), multidetector computed tomography (MDCT) and cone beam computed tomography (CBCT) in detecting vertical root fractures (VRF) in the absence and presence of gutta-percha root filling. METHODOLOGY: The root canals of 100 extracted human single-rooted teeth were prepared and randomly divided into four groups: two experimental groups with artificially fractured root and two intact groups as controls. In one experimental and one control group, a size 40, 0.04 taper gutta-percha cone was inserted in the root canals. Then DR, MDCT and CBCT were performed and the images evaluated. Statistical analyses of sensitivity, specificity and accuracy of each imaging technique in the presence and absence of gutta-percha were calculated and compared. RESULTS: In the absence of gutta-percha, the specificity of DR, MDCT and CBCT was similar. CBCT was the most accurate and sensitive imaging technique (P < 0 .05). In the presence of gutta-percha, the accuracy of MDCT was higher than the other imaging techniques (P < 0.05). The sensitivity of CBCT and MDCT was significantly higher than that of DR (P < 0.05), whereas CBCT was the least specific technique. CONCLUSIONS: Under the conditions of this ex vivo study, CBCT was the most sensitive imaging technique in detecting vertical root fracture. The presence of gutta-percha reduced the accuracy, sensitivity and specificity of CBCT but not MDCT. The sensitivity of DR was reduced in the presence of gutta-percha. The use of MDCT as an alternative technique may be recommended when VRF are suspected in root filled teeth. However, as the radiation dose of MDCT is higher than CBCT, the technique could be considered at variance with the principles of ALARA.

Bioactivity of EndoSequence root repair material and bioaggregate.

AIM: To evaluate the bioactivity of Bioaggregate (BA), EndoSequence Root Repair Material (ERRM), and white ProRoot Mineral trioxide aggregate (MTA). METHODOLOGY: Sixty horizontal root sections with standardized canal spaces were divided randomly into 3 groups (n = 20) and filled with white ProRoot MTA (groups 1 and 2), BA (groups 3 and 4) or ERRM putty (groups 5 and 6). The specimens of groups 1, 3 and 5 (each of 10) were immersed in phosphate-buffered saline (PBS) for 1 week and those of groups 2, 4 and 6 (each of 10) for 2 months. After the experimental periods, the specimens were processed for scanning electron microscopy (SEM) observations. Precipitation of apatite crystals on the surfaces of the cements and/or at the dentine-cement interface was evaluated and analysed elementally by energy dispersive X-ray (EDX) instrument. RESULTS: Analysis of specimens revealed various surface morphologies that were dependent on the material and immersion time in PBS. The formation of precipitates was observed on the surfaces of all materials at 1 week, which increased substantially over time. After 2 months, the surface of the cements was changed dramatically and consisted of a substantially greater amount of apatite aggregates. Interfacial layers in some areas of the dentine-cement interface were found only following 2 months of immersion. Precipitates on MTA revealed high peaks of Ca, Si and O after 1 week of immersion; after 2 months, high peaks of Ca, P and O were present. Precipitates on BA and ERRM displayed high Ca, P O peaks after both 1 week and 2 months. CONCLUSION: Exposure of MTA, BA and ERRM to PBS resulted in precipitation of apatite crystalline structures that increased over time. This suggests that the tested materials are bioactive.

Microstructure and chemical analysis of blood-contaminated mineral trioxide aggregate.

AIM: To test the hypothesis that blood contamination has a detrimental effect on the chemical properties of Mineral trioxide aggregate (MTA). METHODOLOGY: The effects of whole, fresh human blood on the microstructure and elemental chemistry of MTA were evaluated using scanning electron microscopy and energy-dispersive X-ray analysis, respectively. The phase compositions of contaminated and uncontaminated MTA were also analysed using X-ray diffraction analysis. RESULTS: The hydration state of specimens partially mixed with blood were more complete than those mixed entirely with blood and less than those entirely mixed with water. Acicular crystals, characteristic of ettringite, were abundant in specimens mixed entirely with water and absent from specimens mixed partially or entirely with blood. Calcium hydroxide crystals were absent in specimens contaminated entirely with blood and the unhydrated MTA powder, but present in the other groups. CONCLUSION: Mixing MTA with blood resulted in the lack of formation of the crystalline calcium hydroxide in the early stage of the hydration process.

The effect of blood contamination on the compressive strength and surface microstructure of mineral trioxide aggregate.

AIM: To investigate the effects of whole, fresh human blood contamination on compressive strength and surface microstructure of grey and tooth-coloured mineral trioxide aggregate (MTA). METHODOLOGY: The materials investigated were grey ProRoot MTA Original (Dentsply Tulsa Dental, Johnson City, TN, USA) and tooth-coloured ProRoot MTA (Dentsply Tulsa Dental). Three groups of 10 custom-made cylindrical moulds (internal dimensions 6 +/- 0.1 mm length and 4 +/- 0.1 mm diameter) were filled with tooth-coloured MTA. In the control group, MTA was mixed with water and exposed to water. In the second group, MTA was mixed with water and exposed to whole, fresh human blood. In the third group, MTA was mixed with and exposed to whole, fresh human blood. These three groups were then duplicated using grey MTA, creating a total of 60 samples. A predetermined amount of MTA and appropriate liquid were triturated in a plastic mixing capsule then subjected to ultrasonic energy after placement in the moulds. After 4 days of incubation, specimens were subjected to compressive strength testing. The surface microstructure of one extra specimen in each group was examined using scanning electron microscopy. Data were subjected to a two-way anova. RESULTS: Regardless of MTA type, the mean compressive strength values of both experimental groups, which were in contact with blood, were significantly less than that of the control groups (P < 0.0001). In experimental groups in which MTA was mixed with water and exposed to blood, there was a significant difference (P < 0.0001) in compressive strength between tooth-coloured MTA (30.37 +/- 10.16 MPa) and grey MTA (13.92 +/- 3.80 MPa). CONCLUSION: When blood becomes incorporated into MTA, its compressive strength is reduced. In clinical situations in which blood becomes mixed with MTA, its physical properties are likely to be compromised.

The effect of various mixing techniques on the surface microhardness of mineral trioxide aggregate.

AIM: To evaluate the influence of various mixing procedures including ultrasonic vibration, trituration of customized encapsulated mineral trioxide aggregate (MTA) and condensation on the Vickers surface microhardness of MTA. METHODOLOGY: ProRoot MTA Original, ProRoot MTA (white), MTA-Angelus (grey) and MTA White Angelus (white) were prepared using several mixing techniques including ultrasonic vibration, trituration of customized encapsulated MTA and conventional condensation. Twelve experimental groups (four materials: three techniques) were evaluated, each with 35 samples. All samples were incubated after preparation and subjected to Vickers surface microhardness testing after 4 and 28 days. Data was were subjected to a two-way anova. RESULT: At 28 days, the surface microhardness value was significantly greater for all experimental groups compared to 4 days after mixing (P < 0.00001). The application of ultrasonic energy to MTA produced significantly higher surface microhardness values compared to the other mixing techniques at both 4 and 28 days (P < 0.0001). However, no significant difference existed between condensation and trituration techniques at both time intervals. Regardless of the mixing technique employed, a significant difference (P < 0.0001) was observed in surface microhardness value between all types of MTA apart from between Angelus grey and ProRoot white at both 4 and 28 days, both of which produced the highest values. CONCLUSION: Compared to trituration and condensation techniques, the application of ultrasonic energy to MTA produced a significantly higher surface microhardness value at both 4 and 28 days. Irrespective of mixing technique, ProRoot white and Angelus grey had the highest surface microhardness values. Trituration of encapsulated, premeasured MTA and water provides a standardiszed method of mixing that produces MTA slurries with more controllable handling characteristics.

An evaluation of the effect of blood and human serum on the surface microhardness and surface microstructure of mineral trioxide aggregate.

AIM: Short-term and long-term evaluation of the effect of whole human blood or serum contamination on the surface microhardness value and microstructure of white and grey mineral trioxide aggregate (MTA). METHODOLOGY: Three groups of 10 samples for each type of MTA were prepared. The first group was mixed with and exposed to fresh whole human blood. The second and third groups were mixed with distilled water and exposed to fresh whole human blood or human serum, respectively. The control group samples were mixed with and exposed to distilled water. During preparation, 1 g of MTA was triturated with 0.33 g of the selected liquid using an amalgamator and placed inside borosilicate cylindrical moulds. The samples were treated with ultrasonic energy. Vickers surface microhardness values were compared after 4 and 180 days. Scanning electron microscopy (SEM) analysis was performed after 4 days. RESULTS: White MTA had a greater microhardness value than grey MTA in all groups. There was a significant difference between the control and the experimental groups (P < 0.00001). There was no significant difference between the microhardness values obtained after 4 and 180 days, apart from grey MTA mixed with blood or exposed to serum (P < 0.00001). SEM analysis showed the contaminated samples were devoid of acicular crystals that were prominent in the control groups. CONCLUSION: Blood contamination had a detrimental effect on the surface microhardness of MTA in the short and long term. If blood or serum contamination is unavoidable under clinical conditions, it might be preferable to use white MTA.

pH of pus collected from periapical abscesses.

AIM: To determine the pH of pus collected from periapical abscesses. METHODOLOGY: Forty patients (Male = 17/Female = 23) between the ages 17 and 37 years, each with a periapical abscess and with no relevant medical history, were recruited. All the participants had moderate-to-severe pain on percussion accompanied by localized or generalized swelling. At least 1 mL of pus was aspirated from each participant using a No 20 gauge needle. A pH meter was used to define the pH of the pus immediately following aspiration. RESULT: The mean pH of pus from the periapical abscesses of patients was 6.68 +/- 0.324 with a range between 6.0 and 7.3. There was no statistically significant difference in pH by gender or age. CONCLUSION: The mean pH of pus from periapical abscesses was generally acidic, but some samples (two female and three male) were neutral and some samples (four female and one male) were alkaline.