Pulp Temperature Research Articles

Detecting temperature breaks in the initial stages of the citrus export cold chain: A case study

Background: Fruit is an important export commodity for South Africa and accounts for 35% of its agricultural exports. South Africa is the second largest citrus exporter in the world, behind Spain. Maintaining the postharvest cold chain is key to ensuring that fruit quality meets export standards.Objectives: The main objectives of this research were to investigate the frequency, location, magnitude and duration of temperature deviations in the South African leg of the clementine and navel orange cold chain.Method: Temperature trials were conducted on two consignments of clementines and two consignments of navels. Each consignment contained 36 iButtons®, of which 18 measured pulp temperature and 18 measured ambient temperature. Data were successfully retrieved from 130 of the 144 iButtons®.Results: This research identified areas where the temperature went outside the prescribed range along the South African portion of the export cold chain of navel oranges and clementines from Citrusdal, South Africa to the Port of Newark, United States of America.Conclusion: The temperature incidents identified could result in a breach of the cold sterilisation (steri) protocols and quality defects. Recommendations were made to address these deficiencies to improve the South African citrus industry’s global competitiveness.Contribution: This research allowed the citrus industry to investigate and adjust current cold chain practices to improve the integrity of the entire export cold chain, potentially resulting in a higher quality product and increased revenue.

Er:YAG Laser Debonding of Lithium Disilicate Laminate Veneers: Effect of Laser Power Settings and Veneer Thickness on The Debonding Time and Pulpal Temperature.

Introduction: Er:YAG laser is a non-destructive tool for debonding of laminate veneers. This study investigated the effect of different laser powers on the pulp temperature and the time required to perform the debonding of lithium disilicate laminate veneers with different thicknesses. Methods: The labial enamel of 48 maxillary central incisors was flattened and polished. The teeth were restored with flat lithium disilicate ceramic veneers (4.0 mm×6.0 mm) with one of two different thicknesses (0.5 and 1.0 mm). Veneer debonding was performed with an Er:YAG laser with a wavelength of 2940 nm, pulse duration of 100 μm (VSP mode), 10 Hz, and one of the three laser power settings: 1.5 W (150 mJ), 3.0 W (300 mJ). and 5.4 W (540 mJ) (n=8). Veneer detachment time and intra-pulp temperature change (ΔT) were measured. Statistical analysis was performed using the two-way ANOVA and Bonferroni's post hoc test (α=0.05). The correlation between debonding time and temperature change was calculated using Pearson's correlation. Results: The longest time was recorded to remove the 1.0-mm veneer at 1.5 W (P<0.05) and the shortest time was recorded when deboning the 0.5 mm veneer with 5.4 W (P<0.05). ΔT decreased significantly with increasing laser power. A low correlation was found between time and ΔT (R2=0.113). Conclusion: Laser power and veneer thickness are important factors for veneer debonding; thinner veneers are removed faster. When debonding thick veneers, 5.4W laser power is more efficient and causes fewer changes to the pulp temperature.

Effectiveness of carbonate removal and demineralization inhibition in primary teeth using a 9.3-μm carbon dioxide laser

BackgroundStudies on permanent dental enamel have shown that irradiation with a 9.3-μm carbon dioxide (CO2) laser can safely inhibit caries progression in vivo and carieslike lesion formation in vitro. The authors conducted a study to investigate whether 9.3-μm CO2 laser irradiation could safely inhibit carieslike lesion formation in primary teeth in vitro. MethodsTeeth were irradiated with a 9.3-μm CO2 laser at a pulse fluence of 0.8 J/cm2 and scanned automatically over a target area of 5.8 mm2. Two test groups of 15 extracted human molars each were used: (1) laser-irradiated and (2) laser-irradiated plus additional fluoride. Both groups used nonirradiated areas as nonlaser-treated controls. After irradiation, artificial carieslike lesions were generated through a validated pH-cycling protocol. Relative mineral loss (ΔZ) was determined by cross-sectional microhardness testing in depth. Fourier transform infrared spectroscopy was performed on additional 10 irradiated samples to investigate the removal of acid-soluble carbonate groups from the mineral. ResultsInhibition of carieslike lesion formation relative to untreated enamel was (1) laser-irradiated alone: 56.2%, (2) fluoride alone: 55.0%, (3) laser plus fluoride: 76.5% (significantly different from 1 and 2; P < 0.01). Carbonate removal by laser irradiation (SD) was 50.4% (7.7%) at the surface and detectable to a depth of at least 14 μm. ConclusionIrradiation with 9.3-μm CO2 laser on primary teeth reduced the formation of carieslike lesions and was associated with significant removal of acid-soluble carbonate groups from the enamel mineral. This inhibition was accomplished without an unsafe rise in pulpal temperature and without significant microscopic or visible damage to the enamel surface.

How does indirect air-cooling influence pulp chamber temperature in different volume teeth and absence/presence of resin-based composite during light curing?

BackgroundLight-curing of materials during restorative dental procedures poses a risk for pulp tissue overheating. Therefore, the aim of this study was to investigate the effect of indirect air-cooling on pulp chamber temperatures during light-curing of varying volume teeth and absence/presence of resin-based composite (RBC) at different exposure time.MethodsThe volume of 11 human teeth was measured by micro computed tomograph. An experimental rig controlled the thermal environment of the teeth and a thermocouple inserted retrograde into the root canal measured temperature changes. Pulp chamber temperature was measured with and without air-cooling on teeth without and with RBC at 15 s, 30 s and 60 s intervals. Generalized estimating equations were used for statistical analysis.ResultsThe temperature increase with air-cooling (versus no air-cooling) was lower in teeth despite absence/presence of RBC (β = − 4.26, 95%CI − 5.33 and β = − 4.47, 95%CI − 5.60, respectively). With air-cooling, the temperature increase in teeth with RBC was lower compared to teeth without RBC (β = − 0.42, 95%CI -0.79; − 0.05). Higher teeth volume resulted in lower temperature increase with air-cooling than without air-cooling (β = − 0.04, 95%CI -0.07; − 0.01 and β = − 0.17, 95%CI -0.30; − 0.05, respectively).ConclusionsAir-cooling resulted in lower pulp chamber temperature increase. Using air-cooling, the temperature increase was lower in teeth with RBC compared to teeth without RBC. Lower volume teeth resulted in higher temperature increase, thus they seemed to benefit more from air-cooling compared to higher volume teeth. Air-cooling could be an effective tool in controlling pulp temperature increase during light-curing, especially when the tooth volume is small.

Erbium laser-assisted ceramic debonding: a scoping review.

Removal of ceramic restorations and appliances can be time consuming, invasive, and inconvenient. Erbium lasers offer an alternative noninvasive method for debonding of ceramic appliances. This paper aims to provide a comprehensive review of current literature on the effectiveness of erbium lasers for removal of ceramic restorations and appliances from natural teeth and dental implants. A comprehensive search of 7 databases, including Medline (Ovid), Embase, Dentistry and Oral Sciences Source (DOSS), Web of Science, Cochrane Library, and ProQuest Dissertations and Theses was performed. The inclusion and exclusion criteria were agreed prior to the literature search. Two reviewers independently screened the title and abstract. A third reviewer then broke the tie, if any. The selected articles then underwent full text review and the data was extracted. The search identified 4117 unique articles published through June 10, 2021. Studies were assessed and categorized based on the type of restoration/appliance, type of abutment, type of laser, laser settings, efficacy of debonding, and pulpal temperature rise. Thirty-eight full-text articles were reviewed for inclusion. Time for ceramic debonding varies depending on the type of restorations and materials. Removal of zirconia crowns from teeth and implant abutments requires a longer period of time compared to lithium disilicate crowns. Temperature increases were reported as 5.5 degrees or less. Laser setting and laser type affect the debonding time and the increase in temperature. Examinations of debonded ceramics demonstrated no known structural damages resulting from laser applications. Erbium lasers are effective noninvasive tools to remove all ceramic restorations/appliances from natural teeth and implant abutments without causing harm to abutments. Laser-assisted debonding should be considered as a viable alternative to rotary instrumentation for ceramic crowns; however, clinical studies of erbium-assisted ceramic retrieval are needed.

Optimization of the ohmic heating parameters for pasteurization and quality characteristics of mango pulp using response surface methodology

The present investigation optimized the ohmic heating variables influencing the quality parameters of mango pulp during pasteurization. Three independent variables such as voltage gradients (10–20 V/cm) of ohmic heating, pulp temperature (60–80℃) and pulp concentration (6–14 °Brix) were experimented using Box-Behnken experimental design of response surface methodology. The models generated for the quality parameters as responses such as ascorbic acid, total phenol content, overall acceptability, mold load and bacterial load were tested for their validity using ANOVA. The optimum conditions for pasteurization of mango pulp through ohmic heating were found to be 19.5 V/cm, 75°C and 9.96 °Brix respectively for voltage gradient, pulp temperature and pulp concentration. The values of corresponding quality parameters of ascorbic acid content, total phenolics content, overall acceptability, yeast/mold load and bacterial load were estimated to be 129.39 mg/100g dm, 288.006 mg GAE/100 g dm, 7.40, 11.01 cfu/ml and 162.299 cfu/ml respectively. The results were experimentally verified within a deviation of ±0.5%. Structural variations and functional compounds of fresh, conventionally heated and ohmic heated samples at optimum conditions were analyzed through SEM and FTIR respectively. The ohmic heated sample was found superior over conventionally heated sample with maximum retention of quality parameters. Further, the rheological analysis depicted the closeness of ohmic heated (optimum) sample with the fresh sample.

Impact of Resin Composite Restorative Material Pre-heating on Dental Pulp Temperature: A Laboratory study

Impact of Resin Composite Restorative Material Pre-heating on Dental Pulp Temperature: A Laboratory study

On using excess Gibbs energy as an indicator of hydrophobicity in the flotation process

It has been shown that the partial molar excess Gibbs energy (G̅ex) can be used as an indicator of hydrophobicity and hence contributes to explaining the behaviour of collectors in the recovery of minerals by flotation. This is because hydrophobicity of a mineral particle on which a collector is adsorbed is related to the fact that the alkyl chain associated with the collector behaves in the same way as any hydrocarbon would in a non-ideal mixture with water. Such mixtures are quantified thermodynamically by determining the activity coefficient of the hydrocarbon moiety of the collector and hence its G̅ex in the mixture. The present paper is aimed at extending the above concepts in two different ways. Firstly, an investigation is made of the relationship between G̅ex and contact angle and/or recovery for systems such as ionic liquids and aminothiophenols. Secondly, on the basis of the observation that increases in G̅ex are indicative of increases in the hydrophobicity of the mineral particle-collector aggregate, a study was undertaken to examine, respectively, the effects of the presence of electrolytes or alcohols in the system, of pH and changing concentrations of the collector, on G̅ex of the collector alkyl group and hence its hydrophobicity. In the first instance, the relationship between G̅ex and contact angle and recovery is sustained. With respect to the latter, the absence of any correlation between G̅ex and recoveries supported the proposition that the major effect of electrolytes and added alcohols is rather on particle – bubble attachment. Similarly, it is also indicated that since the change in G̅ex is minimal when collector concentration or pulp temperature is increased these changes do not significantly affect the hydrophobicity of the collector-mineral particle and hence also the recovery in a microflotation.

Intrapulpal temperature changes during the cementation of ceramic veneers

Adhesive cementation of ceramic veneers may increase pulpal temperature (PT) due to the combined effect of heat generated by the curing unit and the exothermic reaction of the luting agent (LA). PT increase may induce pulpal damage. The aim was to determine the PT rise during the luting of ceramic veneers (CV) of different thicknesses with light- or dual-curing (LC, DC) adhesive cements as well as pre-heated restorative resin-based composites (PH-RBC). For this a thermocouple sensor was positioned in the pulp chamber of a prepared maxillary central incisor. LC, DC adhesive cements and PH-RBCs heated to 55 °C were used for the luting of CVs of 0.3, 0.5, 0.7, and 1.0 mm thicknesses. The exothermic reaction of LAs added significantly to the thermal effect of the curing unit. PT change ranged between 8.12 and 14.4 °C with the investigated combinations of LAs and ceramic thicknesses (p ≤ 0.01). The increase was inversely proportional to the increasing CV thicknesses. The highest rise (p ≤ 0.01) was seen with the polymerization of PH-RBCs. Temperature changes were predominantly influenced by the composition of the LA, which was followed by CV thickness.

Effect of Blunging/Dispersion Parameters on Separation of Halloysite Nanotubes from Gangue Minerals

Clay minerals need to be dispersed with blungers before their utilization in the related industries due to their plastic properties, and size reduction is carried out in a wet medium. Clay minerals also contain impurities such as nonplastic materials in their structure. Mechanical dispersion parameters are important in the separation of clay group minerals (halloysite and kaolinite) from their typical non-clayey gangue minerals (quartz and goethite). In this study, the removal of impurities from halloysite ore obtained from Kızıldam, Turkey, was examined in terms of mechanical dispersion parameters, namely, feed size, blunging time and speed, pulp concentration, pulp temperature, and the aging process. The effect of these parameters on halloysite dispersion was determined by particle size, chemical, and mineralogical analysis, and optical and scanning electron microscope images. The results obtained from the studies of the mechanical dispersing and particle size distribution of the products indicated that the optimum dispersion parameters were determined as −10 mm feed size, 8 h, and 1000 rpm blunging time, and speed, 35% pulp concentration at 25 °C pulp temperature. Under these optimum conditions, a 72.3% amount of −38 μm clay product containing 35.6% of halloysite, 46.5% of kaolinite, 12.0% quartz, 1.9% goethite, 0.9% gibbsite, and 3.2% other minerals were obtained from the halloysite ore, having 30.5% of halloysite, 43.4% of kaolinite, 19.1% quartz, 2.9% goethite, 1.4% gibbsite, and 2.7% other minerals. In this study, it was understood that feed size, pulp concentration, blunging time, and speed were important parameters, while pulp temperature and the aging process had no significant effect on the mechanical dispersion of Kızıldam halloysite. In addition, impurities such as quartz and iron-bearing minerals were separated from the ore by blunging and sieving.

In Vitro Study of Laser-Assisted Prefabricated Ceramic Crown Debonding as Compared to Traditional Rotary Instrument Removal.

This study compared the laser and rotary removals of prefabricated zirconia crowns in primary anterior and permanent posterior teeth. Sixty-two extracted teeth were prepared for prefabricated zirconia crowns cemented with resin-modified glass-ionomer cement. Specimens underwent crown removals by a rotary handpiece, or erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser. Pulpal temperatures, removal times, and scanning electron microscopy (SEM) examinations were compared. The average crown removal time for rotary and laser methods was 80.9 ± 19.36 s and 353.3 ± 110.6 s, respectively, for anterior primary teeth; and 114.2 ± 32.1 s and 288.5 ± 76.1 s, respectively, for posterior teeth (p < 0.001). The maximum temperature for the rotary and laser groups was 22.2 ± 8.5 °C and 27.7 ± 1.6 °C for anterior teeth, respectively (p < 0.001); and 21.8 ± 0.77 °C and 25.8 ± 0.85 °C for the posterior teeth, respectively (p < 0.001). More open dentinal tubules appeared in the rotary than the laser group. The rotary handpiece removal method may be more efficient than the laser with lower pulpal temperature changes. However, the laser method does not create noticeable tooth or crown structural damage compared to the rotary method.

Influence of pulse duration and water/air cooling ratio on the efficiency of Er:YAG 2940 nm laser in debonding of porcelain laminate veneers: An in vitro study.

ObjectiveTo determine the effectiveness of different pulse durations (PD) and the water/air (W/A) cooling ratio of the Er:YAG 2940 nm laser that are required for debonding porcelain laminate veneers (PLV), by investigation of the needed time for PLV debonding (DT) and the changes in dental pulp temperature.Materials and MethodsThirty‐six extracted noncarious human maxillary premolars were prepared for receiving PLV. Samples were randomly assigned to six different groups, based on PD and the W/A ratio: Groups A (50 µs, 1:1), B (50 µs, 3:3), C (100 µs, 1:1), D (100 µs, 3:3), E (300 µs, 1:1), and F (300 µs, 3:3). Veneers were debonded using laser irradiation by the same parameters (270 mJ, 15 Hz) with noncontact application mode.ResultsAll 36 veneers were debonded. Samples of the 50 and 100 µs PDs showed significantly shorter DT (7.4−17 s) than that of the 300 µs which showed significantly the longest DT (104 s) among all other groups (p < .001). However, the highest elevation of pulp temperature was observed in Group E (300 µs, 1:1) which reached (3.4°C).ConclusionUsing the 50 or 100 µs PD of the Er:YAG laser was more efficient than 300 µs in reducing DT of PLVs with minimal change in pulp temperature. W/A cooling ratio had minimal influence on the DT of PLV.

Temperature change of the pulpal floor and restoration with preheated bis-GMA free and containing resin composite (a randomized clinical trial)

BackgroundPreheating is one of several innovative approaches and improvements developed to increase the durability and clinical behavior of resin composites. Development of preheated composites is to reduce its viscosity in order to improve resin composite adaptation and placement ease. The purpose of this clinical trial was to study the effect of preheating Bis-GMA free and Bis-GMA-containing resin composites at different temperatures on the pulpal floor and restoration temperature. A total of twenty individuals (N = 40) have two carious posterior teeth that need to be restored were randomly assigned to one of two groups based on the type of restorative materials used: (group 1) Bis-GMA-containing resin composite VisCalor bulk (VCB), and (group 2) Bis-GMA-free resin composite Admira Fusion x-tra (AFX). Preheating temperatures of 50 °C and 70 °C were utilized to separate each group into two subgroups. Class I or II cavities were prepared. Thermometer device with two separate K-type temperature probes was used to measure the base line temperature values at the pulpal floor before beginning the restorative procedure (C0), pulpal floor during packing of preheated composite (C1), the top composite surface after packing and before curing (C2), pulpal floor after curing of the preheated composite (C3), and top composite surface after curing (C4). One-way ANOVA and the Kruskal–Wallis test were used to analyze the data.ResultsThe measured temperature of pulpal floor for both preheated VCB or AFX at 50 °C or 70 °C revealed significant increasing from base line measured temperature to during packing as well as after curing with (P-value < 0.001). There was no significant difference for mean composite surface temperature for both preheated materials at 50 °C or 70 °C whether before or after curing.ConclusionsPreheating of bulk fill Bis-GMA free and containing resin composite rises both the pulpal floor and the restoration temperature; meanwhile, the rise in temperature was limited. The application of the curing unit caused the greatest temperature rise.

The Desorption Behavior of Methylcellulose from Talc at Different Temperature of Pulp

The Desorption Behavior of Methylcellulose from Talc at Different Temperature of Pulp

Pulping Yield and Mechanical Properties of Unbeaten Bamboo Paper

One way to minimize emissions of greenhouse gases that contribute to climate change is to reduce the use of wood as the main material for pulp and paper production. Therefore, non-woody plants such as bamboo can be alternatives as raw materials for pulp and paper. This study aims to determine the effect of the different bamboo species and age on the bamboo pulping yield and bamboo mechanical paper properties. Bambusa vulgaris, Gigantochloa levis, and Gigantochloa scortechinii bamboo species or locally known as Aur, Beting, and Semantan bamboo at the age of 1, 3, and 5-year old, were pulped using Soda-Anthraquinone (AQ) pulping. No beating process was conducted to all the papermaking processes to evaluate the basic mechanical properties of the bamboo paper. Pulping yield ranged from 35.7 to 51.7% at different bamboo species and age, with the pulping conditions at 20% of NaOH, 170ºC pulping temperature, 90 min time to reach pulping temperature and 90 min time at pulping temperature, 1:6 of bamboo to liquor ratio and 0.1% of AQ based on bamboo oven-dried weight. The paper was made according to TAPPI Standard T205 sp- 95. The paper mechanical properties for burst index, tear index, tensile index, and folding endurance ranged from 1.32 to 2.36 kPa.m2/g, 7.48 to 14.9 Nm2/g, 16.02 to 29.68 Nm/g, and 2 to 28 double folds, respectively, at different bamboo species and age. It was found that Beting bamboo has the potential to be a viable raw material for pulp and paper products as it shows the highest mechanical properties compared to Aur and Semantan.

Comparative Evaluation of Temperature Rise inside Pulp Chamber Using Two Different Provisional Restorative Materials

Aim: To compare the rise in temperature inside pulp chambers with two different provisional crown prosthesis materials.&#x0D; Study Design: Comparative -in vitro.&#x0D; Place and Duration of Study: Department of Prosthodontics, Liaquat Medical University Hospital from AUGUST 2019 TO DECEMBER 2019.&#x0D; Methodology: The purpose of this study was to evaluate the mean rise in temperature during provisional restoration utilising Polymethyl methacrylate resin (PMMA) versus bis- glycidyl methacrylate resin (Bis-GMA) at in-vitro laboratory of Prosthodontic department, Liaquat University of Medical and Health, Jamshoro. A total number of 60 extracted maxillary central incisor teeth were selected using non probability consecutive sampling technique. Teeth were divided into two groups on the basis of fabrication material used. In group I; Poly-methyl methacrylate resin (PMMA) was used for provisional restoration and in group II; bis-glycidyl methacrylate (Bis-GMA) was used for provisional restoration. Tooth preparations were performed following all the principles. Mean temperature rise was recorded and compared for both material over each tooth using radicular approach after placing the provisional restorations in impression mould.&#x0D; Results: A total number of 60 teeth were selected, out of which 31 (51.67%) were right maxillary central incisor and 29 (48.33%) were left maxillary central incisor. On comparison of mean rise in pulp temperature between the PMMA group and Bis-GMA group, mean rise in temperature was significantly high in PMMA group; 40.59±0.56°C versus 39.40±0.53°C in Bis-GMA group (p-value &lt;0.0001).&#x0D; Conclusion: The mean rise in pulp temperature using Bis-GMA resin was significantly less as compared to the PMMA material. So Bis-GMA should be preferred over PMMA material for provisional restorations.

In-office dental bleaching with violet light emitting diode: bleaching efficacy and pulpal temperature rise.

ObjectivesThis study evaluated the bleaching efficacy of different in-office protocols associated with violet light emitting diode (V-LED), and measured the pulpal temperature rise caused by V-LED with or without gel application.Materials and MethodsBovine incisors were distributed in 4 groups (n = 10): VL – V-LED; HP – 35% hydrogen peroxide (control); HYB – hybrid protocol, V-LED applied without gel for 10 irradiation cycles followed by V-LED applied with gel for another 10 irradiation cycles; and HPVL – gel and V-LED applied for 20 irradiation cycles. Three bleaching sessions were performed with 7-day intervals. Bleaching efficacy was evaluated with , ΔE00 and ΔWID. Data were recorded at baseline, 7, 14, 21 and 70 days. For pulpal temperature rise, thermocouples were placed inside the pulp chamber of human incisors. To determine intrapulpal temperature, the teeth were irradiated with V-LED with or without application of bleaching gel. Color difference data were analyzed by 2-way repeated measures ANOVA and Tukey’s test. Pulpal temperature was analyzed by t-test (α = 5%).ResultsVL exhibited lower color ( and ΔE00) and whiteness changes (ΔWID) than the other groups. HPVL presented higher color change values than HYB. HYB and HPVL showed not different ΔWID values; and HP showed the highest whiteness changes at all times. There were significant differences comparing ΔT with gel (8.9°C) and without gel application (7.2°C).ConclusionsHPLV was more efficient than HYB. The 2 protocols with VL showed similar results to control. Gel application combined with VL promoted higher pulpal temperature than to the no gel group.

ИССЛЕДОВАНИЕ ПРОЦЕССА ЭФФЕКТИВНОГО ИЗВЛЕЧЕНИЯ ОКСИДА ВАНАДИЯ ИЗ ОТРАБОТАННЫХ КАТАЛИЗАТОРОВ НЕФТЕХИМИИ МЕТОДОМ ВЫЩЕЛАЧИВАНИЯ

The process of acid, alkaline and soda leaching of spent petrochemical catalysts to produce vanadium oxide has been studied. The most effective reagent, its consumption, leaching duration and pulp temperature were chosen according to the results of the experiments. 80% extraction of vanadium oxide in the solution was achieved by using sodium hydroxide solution (200 g / l) as a reagent, solid-liquid phase ratio T:L = 1:3, pulp temperature 100 °С, process duration of about 3 hours.

The effect of different pulp capping methods on the intrapulpal temperature when using light-cured procedures.

BackgroundTo evaluate the intra-pulpal temperature during different direct pulp capping methods and light-cured procedures. Material and MethodsClass I preparations 5 mm long, 4 mm wide and 4 mm deep were performed in extracted third molars, leaving 0.5 mm of dentin at the pulpal floor with a 1 mm diameter of pulp exposure. Teeth were placed in a customized oral cavity chamber simulator in which the initial temperature was standardized at 36oC. The overall temperature variations (oC) in the pulp chamber during the light-activation processes were recorded live using an infrared camera (FLIR ONE PRO, FLIR Systems). The liners and bases evaluated were: Dycal (Dentisply), TheraCal LC (Bisco), Biodentin (Septodent), Vitrebond Plus (3M/ESPE), and Fuji IX GP (GC), followed by restoration with a bulk fill composite (EvoCeram Bulk Fill, Ivoclar Vivadent). All light-activation procedures were performed with the VALO Grand (Ultradent) light-curing unit. A power analysis was conducted to determine the sample size to provide a power of at least 0.8 with α=0.05. Statistical analyses were performed using ANOVA and Tukey’s test for multiple comparisons. ResultsThe intrapulpal temperature increased above a 10oC to 20oC threshold difference for all liners and bases that were light cured. When added as second layers, neither of those could provide thermal insulation following additional light-activated procedures (p=0.25). The higher the number of procedures requiring light-activation, the longer the pulp temperature remained in those increased temperature thresholds. ConclusionsFor direct pulp capping procedures, a reduced number light activation procedures should be indicated to reduce the time intra-pulpal temperature rises above a 10oC threshold. Key words:Liner, base, calcium hydroxide, glass ionomer, dental adhesive, bulkfill composite.

Cast‐tape drying and freeze drying of tucumã pulp into powder

AbstractThis study aimed to investigate the drying of tucumã pulp into powder by cast‐tape drying (CTD) and freeze drying (FD). Bioactive compounds and the physicochemical properties of the pulp and powder were investigated. Tucumã pulp (2 mm thick pulp) was dehydrated by cast‐tape drying in a short time (8 min) due to the high drying rate, and by freeze drying for 21 h at 0.02 kPa. The powders presented moisture content of 0.04 g/g (d.b.) and water activity lower than 0.40. The degradation of bioactive compounds was of 55.8 and 37.5% of antioxidant activity index, as well as 50.1 and 26.9% of total phenolic compounds in the pulp dried by CTD and by FD, respectively. The greater degradation of bioactive compounds in the powder obtained by CTD is due to the higher pulp temperature and oxidation reactions. Both drying processes reduced β‐carotene, accounting for 45.8% for powders obtained by CTD and 31.2% by FD. However, the degradation of carotenoids did not influence the color of the pulp reconstituted when compared to the raw pulp. Despite possible biocomposite losses due to drying, the results showed that tucumã powders present relatively good values of bioactive compounds in relation to the data reported in the literature. Therefore, FD and CTD processes are appropriate to dehydrate tucumã pulp without adding carrier agents and that can be marketed without refrigeration, which is essential in regions with transport logistics issues. The advantage of CTD over FD is the higher drying rates.Practical ApplicationsTucumã is a typical exotic fruit from the Amazon region, which is rich in phenolics and antioxidants. This fruit is of great importance in the Amazon and deserves studies that make its conservation viable. Freeze drying and cast‐tape drying processes are considered appropriate conservation methods for the tucumã pulp, as they enable to retain a part of the bioactive compounds of the raw material. Moreover, tucumã powder has potential applications in food, chemical, and pharmaceutical areas.