Coronal Material Research Articles

Web-Based Survey on Regenerative Endodontic Practices among Members of the American Association of Endodontists

IntroductionThe American Association of Endodontics (AAE) Regenerative Endodontics Committee reports here the web-based survey data of regenerative endodontic procedures performed by the AAE members from 2008 to 2019. MethodsThe web-based survey consisted of 2 questionnaires, a revascularization and a follow-up, including clinical and radiographic data at 3, 6, 12 or >12 months after treatment. Data from demographics, etiology, clinical protocols, radiographic, and clinical outcome as perceived by the clinicians were recorded. From 927 entries, 184 full cases were submitted and 126 were suitable for radiographic analysis. The data were divided into cases with 6–12 months and cases with >12 months recall time. Descriptive statistics and univariate analyses were performed. ResultsPredominantly patients were male (63%), average 10 years-old with anterior teeth (77.2%) due to trauma (69.6%). A wide variation in regenerative endodontic procedures protocols was reported by the AAE members. The most common clinical protocols used minimal instrumentation (75.5%), 2.5% or higher concentrations of sodium hypochlorite (83.7%), and antibiotic paste as intracanal medication (58.7%). The majority reported blood clot formation (56%) and most common coronal capping material was white mineral trioxide aggregates (50.5%). Increases in radiographic root length, and radiographic root area were proportional to the time lapsed after treatment. Overall, case outcomes were categorized by clinicians as successful (54.3%), uncertain (23.9%), and unsuccessful (3.8%). ConclusionsThis web-based survey provides a valuable perspective on case selection, clinical protocols, and perceived outcomes for regenerative endodontic procedures and supports the need for future higher level evidence studies.

In vitro and in vivo evaluation of iRoot BP Plus as a coronal sealing material for regenerative endodontic procedures

ObjectivesTo investigate in vitro effects of a nanoparticle bioceramic material, iRoot BP Plus, on stem cells from apical papilla (SCAP) and in vivo capacity to induce pulp-dentin complex formation. Materials and methodsThe sealing ability of iRoot BP Plus was measured via scanning electron microscopy (SEM). SCAP were isolated and treated in vitro by iRoot BP Plus conditioned medium, with mineral trioxide aggregate (MTA) conditioned medium and regular medium used as controls, respectively. Cell proliferation was assessed by BrdU labeling and MTT assay and cell migration was evaluated with wound healing and transwell assays. Osteo/odontogenic potential was evaluated by Alizarin red S staining and qPCR. Pulp-dentin complex formation in vivo was assessed by a tooth slice subcutaneous implantation model.ResultsiRoot BP Plus was more tightly bonded with the dentin. There was no difference in SCAP proliferation between iRoot BP Plus and control groups (P > 0.05). iRoot BP Plus had a greater capacity to elevated cell migration (P < 0.05) and osteo/odontogenic marker expression and mineralization nodule formation of SCAP compared with MTA groups (P < 0.05). Furthermore, the new continuous dentine layer and pulp-like tissue was observed in the iRoot BP Plus group in vivo.ConclusionsiRoot BP Plus showed excellent sealing ability, promoted the migration and osteo/odontogenesis of SCAP and induced pulp-dentin complex formation without affecting the cell proliferation, which indicated iRoot BP Plus was a promising coronal sealing material in REPs.Clinical relevanceThe coronal sealing materials play crucial roles for the outcomes of REPs. This study showed that iRoot BP Plus has good coronal sealing and promote pulp-dentin complex formation compared with MTA, providing experimental evidences for the clinical application of iRoot BP Plus as a promising coronal seal material in REPs.

Common Temporization of Access Cavity and Pulp Spacers Practiced by Endodontists in Saudi Arabia: A Cross-sectional Study

Background: Temporary restorations are necessary for preventing coronal leakage during and after treatment completion and must provide an effective barrier against salivary contamination of the root canal system. Endodontic spacers also help remove temporary restoration by avoiding the chances of unwanted intact tooth structure loss and perforation on the floor of the pulp chamber and prevent temporary restorative materials entrapment into the root canals resulting in canal blockage. However, the cotton pellet placed between the temporary and the root canal orifice can compromise the coronal seal by the reduction in thickness of temporary restoration. Objective: The primary aim of this investigation was to determine the most common temporary restoration used during and after endodontic treatment. The secondary aim is to know the percent preference for restorations with double seal and the frequency of spacer used. Methods: Four hundred fifty online questionnaires comprising 15 (four demographic questions and eleven questions related to the study objective) were sent to endodontists in Saudi Arabia via WhatsApp and Twitter. Statistical significance was set at P&lt;0.05 when assessed using a chi-square test. Results: About 370 (82.22%) participants completed the survey. Glass ionomer cement (GIC) was most used as a temporary restoration among endodontists for both the anterior (53%) and posterior teeth (49.7%; P=0.001). In double seal, Cavit was most used as the temporary restoration, which was placed below the seal exposed orally 56.2% (P=0.001). GIC was most used as coronal seal material placed over Cavit in 71.9% of the participants (P=0.001). About 56.2% of the endodontists placed cotton pellets between visits but not after obturation (P=0.001). Polytetrafluoroethylene tape instead of cotton pellet was preferred by 30.3% of the participants (P=0.001). Conclusion: Glass ionomer cement (GIC) was most used as a temporary restoration. In double seal, GIC was most used as coronal seal material placed over Cavit. A pulp spacer was found to be the most commonly used between visits but not after obturation.

Observations of Mini Coronal Dimmings Caused by Small-scale Eruptions in the Quiet Sun

Small-scale eruptions could play an important role in coronal heating, generation of solar energetic particles (SEPs), and mass source of the solar wind. However, they are poorly observed, and their characteristics, distributions, and origins remain unclear. Here a mini coronal dimming was captured by the recently launched Solar Orbiter spacecraft. The observations indicate that a minifilament eruption results in the dimming and takes away approximately (1.65 ± 0.54) × 1013 g of mass, which also exhibits similar features as the sources of SEP events. The released magnetic free energy is of the order of ∼1027 erg. Our results suggest that weak constraining force makes the flux rope associated with the minifilament easily enter a torus-unstable domain. We discuss that weak magnetic constraints from low-altitude background fields may be a general condition for the quiet-Sun eruptions, which provide a possible mechanism for the transport of coronal material and energy from the lower to the middle or even higher corona.

Attitude and practice of regenerative endodontic procedures among endodontists and paediatric dentists: A multinational survey from 13 countries.

Regenerative endodontics (RET) refers to biologically based procedures that aim to restore damaged tooth structures and reinstate the pulp-dentine complex to its normal physiological state. The purpose of this study was to examine the attitudes and practices of endodontists and paediatric dentists regarding RET. A survey was conducted among endodontists and paediatric dentists from 13 countries. A number of factors were evaluated, including frequency of RET application, followed guidelines, disinfection techniques, intracanal medication type, scaffold type, preferred coronal seal material, and follow-up period. Among the 1394 respondents, 853 (61.2%) and 541 (38.8%) were endodontists and paediatric dentists, respectively. Almost half (43%) of participants have not performed RET yet. The American Association of Endodontics guideline (47.3%) was selected as the primary source for the clinical protocol. The most frequently selected irrigant solution was 1.5%-3% NaOCl at the first (26.1%) and second (13.6%) sessions. A blood clot (68.7%) and MTA (61.9%) were the most frequently selected scaffold type and coronal barrier. Most participants preferred a 6-month follow-up period. According to this survey, deviations exist from current RET guidelines regarding all aspects evaluated. Standardizing clinical protocols and adhering to available guidelines would help to ensure more predictable outcomes.

Clinical and radiographic evaluation of NeoMTA versus conventional white mineral trioxide aggregate in revascularization of non-vital immature permanent anterior teeth (A randomized controlled trial)

ObjectiveTo evaluate and compare clinically and radiographically the effect of using two different coronal plug materials (NeoMTA versus Conventional White mineral trioxide aggregate) in revascularization of non-vital immature permanent anterior teeth, with special reference to the assessment and evaluation of discoloration potential over a period of one year.MethodsRevascularization procedure was performed in (30) immature permanent non-vital anterior teeth which were randomly allocated to two equal groups (n = 15). NeoMTA was used as coronal plug material in the Experimental Group (N), while conventional White mineral trioxide aggregate (WMTA) was used as a coronal plug material in the Control Group (W). All treated teeth were evaluated clinically at 1 week, 1, 3, and 12 months and radiographically at 12 months.ResultsThe overall clinical and radiographic success rate of Groups (N) and (W) at the end of the 12-month follow-up period was 100%. The discoloration was detected in a single tooth (9.1%) in Group (N) and three teeth (27.3%) in Group (W) but the difference between groups was not statistically significant.ConclusionsBoth NeoMTA and conventional WMTA were successful coronal plug materials in the revascularization of non-vital immature permanent teeth achieving a high level of clinical and radiographic success. NeoMTA is a promising coronal plug material that can be used for revascularization procedures in the esthetic zone as it showed less discoloration potential compared with conventional WMTA, however, there was no statistically significant difference between both materials.

Origin of Quasi-periodic Pulsation at the Base of a Kink-unstable Jet

We studied a blowout jet that occurred at the west limb of the Sun on 2014 August 29 using high-resolution imaging/spectroscopic observations provided by the Solar Dynamics Observatory/Atmospheric Imaging Assembly and the Interface Region Imaging Spectrograph. An inverse γ-shaped flux rope appeared before the jet–morphological indication of the onset of kink instability. The twisted field lines of the kink-unstable flux rope reconnected at its bright knot and launched the blowout jet at ≈06:30:43 UT with an average speed of 234 km s−1. Just after the launch, the northern leg of the flux rope erupted completely. The time–distance diagrams show multiple spikes or bright dots, which is the result of periodic fluctuations, i.e., quasi-periodic fluctuations (QPPs). The wavelet analysis confirms that QPPs have a dominant period of ≈3 minutes. IRIS spectra (Si iv, C ii, and Mg ii) may also indicate the occurrence of magnetic reconnection through the existence of broad and complex profiles and bidirectional flows in the jet. Further, we found that line broadening is periodic with a period of ≈3 minutes, and plasma upflow always occurs when the line width is high, i.e., multiple reconnection may produce periodic line broadening. The emission measure (EM) curves also show the same period of ≈3 minutes in different temperature bins. The images and EM show that this jet spire is mainly cool (chromospheric/transition region) rather than hot (coronal) material. Further, line broadening, intensity, and EM curves have a period of ≈3 minutes, which strongly supports the fact that multiple magnetic reconnection triggers QPPs in the blowout jet.

Detailed composition of iron ions in interplanetary coronal mass ejections based on a multipopulation approach

Context. Coronal mass ejections (CMEs) are extremely dynamical, large-scale events in which plasma – but not only the coronal plasma – is ejected into interplanetary space. If a CME is detected in situ by a spacecraft located in the interplanetary medium, it is then called an interplanetary coronal mass ejection (ICME). This solar activity has been studied widely since coronagraphs were first flown into space in the early 1970s. Aims. Charge states of heavy ions reflect important information about the coronal temperature profile due to the freeze-in effect and it is estimated that iron ions freeze in at heights of ∼5 solar radii. However, the measured charge-state distribution of iron ions cannot be composed of only one single group of plasma. To identify the different populations of iron charge-state composition of ICMEs and determine their sources, we developed a model that independently uses two, three, and four populations of iron ions to fit the measured charge-state distribution in ICMEs detected by the Advanced Composition Explorer (ACE) at 1 AU. Methods. Three parameters are used to identify a certain population, namely freeze-in temperature, relative abundance, and kappa value (κ), which together describe the potential non-Maxwellian kappa distributions of coronal electrons. Our method chooses the reduced chi-squared to describe the goodness of fit of the model to the observations. The parameters of our model are optimized with the covariance-matrix-adaptation evolution strategy (CMA-ES). Results. Two major types of ICMEs are identified according to the existence of hot material, and both, that is, the cool type and the hot type, have two main subtypes. Different populations in those types have their own features related to freeze-in temperature and κ. The electron velocity distribution function usually contains a significant hot tail in typical coronal material and hot material, while the Maxwellian distribution appears more frequently in mid-temperature material. Our model is also suitable for all types of solar wind and the existence of hot populations as well as the change of temperatures of individual populations may indicate boundaries between ICMEs and individual solar wind streams.

The role of cooling induced by mixing in the mass and energy cycles of the solar atmosphere

ABSTRACT In many astrophysical systems, mixing between cool and hot temperature gas/plasma through Kelvin–Helmholtz-instability-driven turbulence leads to the formation of an intermediate temperature phase with increased radiative losses that drive efficient cooling. The solar atmosphere is a potential site for this process to occur with interaction between either prominence or spicule material and the solar corona allowing the development of transition region material with enhanced radiative losses. In this paper, we derive a set of equations to model the evolution of such a mixing layer and make predictions for the mixing-driven cooling rate and the rate at which mixing can lead to the condensation of the coronal material. These theoretical predictions are benchmarked against 2.5D MHD simulations. Applying the theoretical scalings to prominence threads or fading spicules, we found that as a mixing layer grows on their boundaries this would lead to the creation of transition region material with a cooling time of ∼100 s, explaining the warm emission observed as prominence threads or spicules fade in cool spectral lines without the requirement for any heating. For quiescent prominences, dynamic condensation driven by the mixing process could restore ∼18 per cent of the mass lost from a prominence through downflows. Overall, this mechanism of thermal energy loss through radiative losses induced by mixing highlights the importance for considering dynamical interaction between material at different temperatures when trying to understand the thermodynamic evolution of the cool material in the solar corona.

Short fiber reinforced composite on fracture strength of immature permanent anterior teeth with simulated regenerative endodontic procedures: an in vitro study.

The aim of the present study was to evaluate the effect of short fiber reinforced composite on the fracture strength of anterior immature teeth treated with regenerative endodontic procedures. A total of 120 permanent maxillary central incisors were selected, and root lengths were standardized. Except for the positive control group (n = 20), the root canals were instrumented to simulate immature teeth with incomplete root development, and the regenerative endodontic procedure was performed. Twenty instrumented teeth acted as negative controls (n = 20), and the remaining 80 teeth were randomly divided into 4 groups according to the chosen coronal restoration material: bulk fill, short fiber reinforced composite (SFRC), polyethylene fiber (Ribbond Ultra), and flowable composite resin. Each specimen was then subjected to fracture testing using a universal testing machine (AGS-X, Shimadzu, Japan). The load to fracture was recorded. Data were subjected to statistical analysis using analysis of variance and the Tukey Honestly Significant Difference test. A significant difference was detected between the groups (p < 0.05), with the positive control group showing the highest mean fracture strength. The SFRC group had significantly higher values than the bulk fill, polyethylene fiber, flowable composite resin and negative control groups. In conclusion, SFRC has a relatively high fracture strength compared to other materials used in regenerative endodontic procedures. The use of SFRC enhanced the fracture strength of immature permanent teeth.

Dynamic Evolution of Magnetic Flux Ropes in Active Region 11429. I. EUV Observations

Studying the formation and dynamic evolution of the magnetic flux rope (MFR) is key to understanding the physics of most solar eruptions. In the present study, we investigate the dynamic evolution of four MFRs, which involve in a major eruption. The MFR1, which represents as filament (F1), first appears about 31 hr before the major eruption. The MFR2 appears as a hot-channel with a small filament (F2) in its east part. The hot-channel becomes intermittently visible about 2 hr before the major eruption. The MFR3 is formed by the reconnection between MFR1 and MFR2. The annular components of MFR3 along the MFR2 part appear as a hollow helical structure from the background with the temperature of several MK after the reconnection. Coronal material then flows along the hollow structure from MFR1 part to MFR2 part to form a new filament (F3), which is hosted by MFR3 and acts as the axial component of MFR3 in the following evolution. The MFR4 appears during MFR3's eruption phase as conjugated extreme ultraviolet (EUV) brightenings. Both brightenings extend outward into irregular ribbons with conjugate EUV dimmings inside. Meanwhile, an erupted hot-channel, which roots in the conjugated brightening, is identified. The morphology of the MFRs are also profiled by four associated flare ribbon pairs. The on-disk observations shed light on our understanding of the topology of the MFRs and their formation and eruption. Further work should lay emphasis on the magnetic environment for the MFR formation and evolution.

Evaluation of the microbial, cytotoxic and physico-chemical properties of the stainless steel crowns used in pediatric dentistry

Preformed stainless steel crowns are used in pediatric dentistry to obtain full crown restoration of primary molar teeth. They are consider the best restoration in terms of durability and effectiveness. The purpose of this study is to evaluate microbial, cytological and physio-chemical properties to determine whereas stainless steel crown are biocompatible, safe for surrounding tissue and helpful in avoiding micro-organisms influence on the tooth tissue. Based on the results, it was determined that stainless steel crowns used in pediatric dentistry represent no cytotoxic risk to the surrounding tissues, have a low probability of developing hypersensitivity to the coronal material and also that their biological properties make them suitable to use in pediatric dentistry for the reconstruction of damaged primary molar tissue.

Hemisection with crown splinter in perforation mesial canal wall first molar mandible: a case report

Background: Untreated progressive inflammatory periodontal disease can affect attachment loss until bifurcation or trifurcation of multirooted teeth. Hemisection in multirooted is removal of compromised root preserve the good one then restorative coronal part with a fixed prosthesis. It is the treatment option for preserving the remaining part of healthy root who having sound periodontium. The study aimed to describe a case of a hemisection is presented for a tooth where only the mesial root of a mandibular molar was affected.Case presentation: a 22 years old female comes to RSGM Prof. Soedomo with moderate pain and gum swelling. Perforation in mesial root canal wall in the objective examination. In radiograph, there were radiolucent in mesial root, bifurcation and fracture instrument left in mesial apical root canal. The conditions that can't approach in non-surgical treatment such as fracture instrument, severe vertical bone loss, caries, internal or external resorption in furcation or one root, and furcation lesion, can be treated with surgical approach hemisection as alternative before axtraction teeth. Hemisection treatment includes root canal treatment of the remaining roots, intracanal retention with fiber post then restorative the coronal part use restorative material and splinting with the adjacent tooth to decrease the risk of displacement. Fixed prosthodontic prosthesis to maintain the occlusal balance.Conclusion: hemisection is a feasible treatment option because more practical and conservative for periodontal-endodontic lesions rather than extraction teeth.

Thomson Scattering in the Lower Corona in the Presence of Sunspots

Abstract Polarized scattered light from low (few tens of megameter altitudes) coronal transients has been recently reported in Solar Dynamics Observatory/Helioseismic and Magnetic Image (HMI) observations. In a classic paper, Minnaert (1930) provided an analytic theory of polarization via electron scattering in the corona. His work assumed axisymmetric input from the photosphere with a single-parameter limb-darkening function. This diagnostic has recently been used to estimate the free-electron number and mass of HMI transients near the solar limb, but it applies equally well to any coronal material, at any height. Here we extend his work numerically to incorporate sunspots, which can strongly effect the polarization properties of the scattered light in the low corona. Sunspot effects are explored first for axisymmetric model cases, and then applied to the full description of two sunspot groups as observed by HMI. We find that (1) as previously reported by Minnaert, limb darkening has a strong influence, usually increasing the level of linear polarization tangential to the limb; (2) unsurprisingly, the effects of the sunspot generally increase at the lower scatterer altitudes, and increase the larger the sunspot is and the closer to their center the scatterer subpoint is; (3) assuming the Stokes Q &gt; 0 basis to be tangential to the limb, sunspots typically decrease the Stokes Q/I polarization and the perceived electron densities below the spotless case, sometimes dramatically; and (4) typically, a sizeable non-zero Stokes U/I polarization component will appear when a sunspot’s influence becomes non-negligible. However, that is not true in rare cases of extreme symmetry (e.g., scattering mass at the center of an axisymmetric sunspot). The tools developed here are generally applicable to an arbitrary image input.

Two-fluid simulations of Rayleigh-Taylor instability in a magnetized solar prominence thread

Solar prominences are formed by partially ionized plasma with inter-particle collision frequencies generally warranting magnetohydrodynamic treatment. In this work we explore the dynamical impacts and observable signatures of two-fluid effects in the parameter regimes when ion-neutral collisions do not fully couple the neutral and charged fluids. We perform 2.5D two-fluid (charges-neutrals) simulations of the Rayleigh-Taylor instability (RTI) at a smoothly changing interface between a solar prominence thread and the corona. The purpose of this study is to deepen our understanding of the RTI and the effects of the partial ionization on the development of RTI using nonlinear two-fluid numerical simulations. Our two-fluid model takes into account neutral viscosity, thermal conductivity, and collisional interaction between neutrals and charges: ionization–recombination, energy and momentum transfer, and frictional heating. In this paper, the sensitivity of the RTI dynamics to collisional effects for different magnetic field configurations supporting the prominence thread is explored. This is done by artificially varying, or eliminating, effects of both elastic and inelastic collisions by modifying the model equations. We find that ionization and recombination reactions between ionized and neutral fluids do not substantially impact the development of the primary RTI. However, such reactions can impact the development of secondary structures during the mixing of the cold prominence and hotter surrounding coronal material. We find that collisionality within and between ionized and neutral particle populations plays an important role in both linear and nonlinear development of RTI; ion-neutral collision frequency is the primary determining factor in development or damping of small-scale structures. We also observe that the degree and signatures of flow decoupling between ion and neutral fluids can depend on the inter-particle collisionality and on the magnetic field configuration of the prominence thread.

What determines the unique spectra of super-Eddington accretors? Origin of optically thick and low-temperature coronae in super-Eddington accretion flows

Abstract The existence of relatively cool (kBT ≲ 10 keV) and optically thick (τ ≳ 3) coronae are inferred above super-Eddington accretion flow such as ultraluminous X-ray sources, GRS 1915+105, and narrow-line Seyfert 1 galaxies, which contrasts with cases in sub-Eddington accretion flows, which are associated with coronae with kBT ∼ 100 keV and τ ∼ 1. To understand their physical origin, we investigate the emission properties of the corona which is formed by the gas blown off the super-Eddington inner disk by radiation pressure. We assume that the corona is heated by the reconnection of magnetic loops emerging from the underlying disk. We show that this radiation-pressure-driven wind can act as an optically thick corona which upscatters thermal soft photons from the underlying disk, and that with a reasonable parameter set we can theoretically reproduce the coronal optical depth and temperature which are inferred by spectral fittings of observational data. By contrast, the coronal optical depth cannot be so high in sub-Eddington cases, since the coronal material is supplied from the disk via evaporation and there is a maximum limit on the evaporation rate. We suggest that low-temperature, optically thick Comptonization should be a key signature of super-Eddington accretion flow.

Insight-HXMT observations of jet-like corona in a black hole X-ray binary MAXI J1820+070

A black hole X-ray binary produces hard X-ray radiation from its corona and disk when the accreting matter heats up. During an outburst, the disk and corona co-evolves with each other. However, such an evolution is still unclear in both its geometry and dynamics. Here we report the unusual decrease of the reflection fraction in MAXI J1820+070, which is the ratio of the coronal intensity illuminating the disk to the coronal intensity reaching the observer, as the corona is observed to contrast during the decay phase. We postulate a jet-like corona model, in which the corona can be understood as a standing shock where the material flowing through. In this dynamical scenario, the decrease of the reflection fraction is a signature of the corona’s bulk velocity. Our findings suggest that as the corona is observed to get closer to the black hole, the coronal material might be outflowing faster.

Clinical efficacy observation of direct pulp capping using iRoot BP Plus therapy in mature permanent teeth with carious pulp exposure

Objective: To evaluate the clinical efficacy and influence factors of direct pulp capping using a bioactive ceramic in mature permanent teeth with carious pulp exposure, in order to explore the feasibility and indications of vital pulp therapy for such teeth. Methods: From January 2016 to September 2017, 57 patients (57 teeth) with carious pulp exposure in mature permanent teeth were selected from the Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology. All the teeth were preoperatively diagnosed as deep caries with normal pulp or reversible pulpitis. After rubber dam isolation, all the carious dentin was removed and the exposed pulp tissue was observed under microscope. Hemostasis should be achieved within 3 min by using 2.5% sodium hypochlorite cotton pellets with a gently press. A resin composite restoration was performed immediately or 2 weeks later after direct pulp capping by using a bioceramic material (iRoot BP Plus). The patients were re-examined 12 to 50 months after operation (average 30 months) and the outcomes were evaluated by symptoms, clinical examination and X-ray. Kaplan-Meier survival analysis was used to calculate the success rate and influence factors were analyzed by Log-Rank test. Results: Totally 50 patients [age (32±13) years old (13-68 years old), 12 males and 38 females] received the follow-up examination more than one year. The overall success rate was 90% (45/50) and the success rates at 1 year, 2 years, 3 years and more were 98%, 89% and 81%, respectively. Age, gender, symptom, tooth and cavity type, pulpal exposure size and coronal restoration material had no significant correlations with the treatment outcome (P>0.05). Conclusions: Direct pulp capping of mature permanent teeth with carious pulp exposure by using iRoot BP Plus might have high success rate. There's no significant correlations between the major clinical factors and the treatment outcome.

Micro-CT analysis of the marginal adaptation and porosity associated with ultrasonic activation of coronally placed tricalcium silicate-based cements.

This study aimed to evaluate the effect of ultrasonic activation on coronal marginal adaptation and microporosity of tricalcium silicate-based materials. Sixty freshly extracted human maxillary lateral incisor teeth were instrumented with ProTaper Next X2 files followed by Peeso-Reamer burs, sizes 1 to 5. The specimens were randomly divided into six groups (n=10): Group 1, Biodentine+hand condensation; Group 2, Biodentine+ultrasonic activation; Group 3, NeoMTA Plus+hand condensation; Group 4, NeoMTA Plus+ultrasonic activation; Group 5, ProRoot WMTA+hand condensation; and Group 6, ProRoot WMTA+ultrasonic activation. All tested materials were mixed mechanically and placed 2mm underneath the cement-enamel junction by hand condensation or indirect ultrasonic activation. Volumetric analysis of the voids between the dentine wall and coronal barrier material and the porosity within the material was evaluated with micro-CT. There was no significant difference in marginal adaptation among the six groups (P>0.05). Ultrasonic activation favoured a reduced microporosity in Biodentine Group (P<0.001).

Marginal integrity of aesthetic restorations following intracoronal bleaching with sweet potato extract as an additive: An SEM study

The aim of this in vitro study was to evaluate the marginal integrity of an alkasite restoration in comparison to that of a conventional composite resin restoration following intra-coronal bleaching with 30% hydrogen peroxide (HP) containing sweet potato extract (SPE) as an additive. Access cavities were prepared in 60 extracted human incisors. The teeth were decoronated 2mm below the CEJ and the pulp chambers were sealed cervically. The samples were divided into two groups (n = 30) based on the type of restorative material - group I: Hybrid composite resin and group II: Alkasite restorative material. Both the groups were divided into three subgroups (n = 10) based on the intra-coronal bleaching agent used namely, subgroup A: no bleaching (NB); subgroup B: 30% hydrogen peroxide (HP) and subgroup C: 30% hydrogen peroxide containing SPE (HSP). The tooth-restorative interface was observed under a scanning electron microscope (SEM) to determine the marginal integrity. The results were tabulated and statistically analyzed using one-way ANOVA. Specimens bleached with HP alone showed higher marginal gaps, irrespective of the restorative material used. Subgroups A and C showed lesser marginal gaps under both the restorative materials. An improved marginal integrity was seen with the alkasite material. It can be concluded that the addition of SPE to HP improves the marginal integrity of the coronal restorative material placed immediately post-bleaching. The new alkasite material holds promise as a permanent coronal seal in cases of intra-coronal bleaching.