Pulp Temperature Research Articles

Optimization of ethanol-alkali delignification of false banana (Ensete ventricosum) fibers for pulp production using response surface methodology

The present study investigated the delignification of false banana (Ensete ventricosum) fibers obtained as a crop residual material using sulfur-free ethanol-alkali pulping. Response surface methodology with central composite experimental design was used to evaluate the effects of four independent process variables (pulping temperature, time, ethanol concentration and alkali concentration) on pulp yield, kappa number, brightness, whiteness and yellowness of pulp. The major parameters influencing pulp yield and kappa number were found to be the alkali concentration followed by temperature. For the predicted optimal pulping conditions, the pulp yield was 69.9% with 4.9 kappa number and 64.5% brightness. The ethanol-alkali pulp obtained at center conditions was characterized by viscosity and strength properties and compared with Kraft pulp, showing comparable burst, tensile strength and tear strength. Results suggest that the valorization of the Enset fibers for production of well delignified, high yield and resistant pulp is a promising approach.

An ex-vivo model to determine dental pulp responses to heat and light-curing of dental restorative materials

AimBased on histological studies from the 1960s, it is recommended that dental pulp temperature increases should not exceed 5.5 °C. However, no contemporary reliable models exist to explore the effects of heat on living dental pulp. The aim of this project was to develop a clinically valid model for studying temperature increases caused by three commonly-used light curing units (LCUs). MethodsTemperature increases caused by LCUs at varying exposure times and via various thicknesses of dentine were recorded using traditional approaches (i.e. thermocouple device on a laboratory bench) and an ex-vivo tooth slice model. Histomorphometric and immunohistochemical (IL-1β, HSP70, caspase-3) analysis was performed of the tooth slice model following varying exposure and culture times. ResultsReduced dentine thickness and increased exposure time led to increases in temperature. Whilst the majority of temperature increases recorded using the traditional approach (53 of 60) were greater than the recommended 5.5 °C, 52 of the 60 reference points recorded using the ex-vivo tooth slice model resulted in temperature increases of less than 5.5 °C. Temperature increases of 5.5 °C or more that are prolonged for 40 s caused an immediate decrease in cell number. IL-1β was not detected in any samples, while HSP70 was detectable immediately after exposure to a temperature increase of 6 °C or more. Higher levels of HSP70 were detected after 24 h culture in tooth slices that experienced a temperature increase of 7.5 °C or more. Low levels of caspase-3 were detected in tooth slices exposed to temperature increase of 7.5 °C or more. ConclusionExperimental arrangements for assessing LCU performance that measure temperature increases using a thermocouple device on a laboratory bench should no longer be used. Future studies in this area should include replication of the clinical environment using greater sophistication, such as the use of an ex-vivo tooth slice model as described here. Temperature increases of 5.5 °C or more for 40 s caused an immediate decrease in cell number, which supports previous findings. However, complex interactions at an immunohistochemical level suggest that while temperature increases of 5 °C or less are ideal, there may be some cell damage between 5–7 °C which might not result in pulpal death. Further investigations are indicated.

Effect of temperature on floatability and adsorption behavior of fine wolframite with sodium oleate

The influence of pulp temperature on the floatability and adsorption behavior of fine wolframite with sodium oleate was investigated by microflotation experiments, electric conductivity tests, adsorption measurements, and FT-IR analysis. Microflotation results show that fine wolframite with sodium oleate exhibits a good floatability at pH 8–9. Electric conductivity tests indicate that the high temperature enhances the ionization degree and electric mobility of oleate species, then the flotation recovery of fine wolframite and the adsorption amount of sodium oleate are observed to increase with the rise in pulp temperature. The results of adsorption experiments are found to meet Freundlich isotherms successfully, and the isosteric enthalpy (ΔHΘ) is in conformity with the chemical bonding. The changes in FT-IR analysis provide sufficient evidence that sodium oleate interacts with the metal cations of wolframite surface, and the increase in pulp temperature clearly promotes the chemisorption intensity. These findings will be beneficial to strengthen the flotation behavior of fine wolframite.

Er:YAG Laser for Metal and Ceramic Bracket Debonding: An In Vitro Study on Intrapulpal Temperature, SEM, and EDS Analysis.

To evaluate the effects of bracket removal using an erbium laser on the pulp temperature and enamel surface. Removal of orthodontic brackets with conventional debonding pliers may result in enamel cracks. To avoid damage to the enamel surface and effectively remove metal or ceramic brackets, different types of lasers, such as Nd:YAG, CO2, TM:YAP, diode laser, or Er:YAG, have been introduced for debonding. A total of 55 brackets (n = 55; 20 metal and 35 ceramic ones) were bonded to 55 caries-free premolars extracted for orthodontic indications. Brackets were irradiated with Er:YAG laser (Morita, Irvine, CA) with a wavelength of 2940 nm at a power of 3.4 W, energy 170 mJ, frequency 20 Hz, pulse duration 300 μs, tip diameter 0.8 mm, air/fluid cooling 3 mL/s, and time of irradiation: 6 sec. Debonding was made by scanning (n = 15; 6 sec irradiation at distance of 2 mm from the bracket with an "S" shape movement) and circular (n = 15; 6 sec irradiation at distance of 1 mm from the bracket) motion technique in ceramic brackets or the circular motion technique in metal brackets (n = 15). The number of 10 nonirradiated teeth with ceramic (n = 5) or metal brackets (n = 5) was used as a control in SEM test and EDS analysis. The damage in tooth enamel surface and the calcium percentage were analyzed by means of scanning electron microscope (JEOL 6610LV, JEOL, Japan) and energy dispersive X-ray spectroscopy (EDS, Oxford, United Kingdom). Temperature changes in the pulp were measured by K-type thermocouple. Evaluation of the Adhesive Remnant Index (ARI) on the enamel surface of each tooth was examined after bracket debonding. The scanning method has caused significantly lower temperature increase (mean: 0.83°C) compared with circular motion technique around the ceramic brackets (mean: 1.78°C; p = 0.0001) or the metal brackets (mean: 1.29°C; p = 0.015). ARI score showed no differences between the study groups (p = 0.57). SEM analysis revealed no cracks on enamel surface after laser-assisted debonding in comparison with the control samples where cracks were found. EDS showed a higher mean percentage of the calcium (30.7-85.8%) for all test groups compared with control samples (mean: 7%; p = 0.0002). The amount of the calcium elements was higher for metal brackets in comparison with ceramic ones (p = 0.0002). Er:YAG laser-assisted debonding causes a minor increase in the pulp temperature and reduced the risk of enamel damage compared with conventional bracket removal.

Effect of process variables on the drying of guava pulp by cast-tape drying

Cast-tape drying (CTD) is a relatively new technique for dehydration and production of food powders. A solution or suspension is spread over a flexible support heated by water or steam. This study investigated the effect of flexible support type (polyester film – Mylar® or fiberglass coated with Teflon®) and pulp layer thickness (2 mm and 3 mm) on drying rate and temperature of guava pulp processed by CTD. All drying curves presented constant-rate period, which was 2.1 greater using 2 mm thick-pulp than 3 mm thick-pulp, for both Mylar® and Teflon®. Using same pulp thickness, similar drying rates and evaporative capacities were observed for both flexible supports. Guava pulp was less sticky on Teflon® than on Mylar® support and that is an advantage. Therefore, cast-tape drying can be used for production of guava powder with high drying rates and evaporative capacities.

Evaluation of temperature changes in the pulp chamber during polymerization of pulp capping materials

Polymerization of resin-based materials leads to temperature rise, caused by the exothermic nature of the reaction and energy absorbed during polymerization. This temperature rise is influenced by intensity of light, composition of resins, and type of light source. This study evaluated thermal insulating properties of four photo-polymerizing pulp-capping agents in primary and permanent teeth. Roots of 80 primary and permanent teeth were removed. Class-I cavities were prepared on the occlusal surfaces of teeth. Materials used were TheraCal LC, Biner LC, ACTIVA BioACTIVE, and Calciplus LC and light sources were 3 M-Elipar and VALO LED. Temperature rise was measured using a J-type thermocouple. Data were statistically evaluated using ANOVA and Tukey`s tests (p = 0.05). VALO LED exhibited significantly lower temperature rise in all groups and temperature rise in primary teeth was significantly higher with all experimental materials (p < 0.05). The highest temperature change was observed in the Biner LC group (3.82 ± 0.58) and the lowest change in the Activa-BioACTIVE group (1.78 ± 0.34). The VALO LED light source caused a significantly lower increase in pulpal temperature compared with the 3 M-Elipar source. All tested materials and light sources maintained pulpal temperature under safe limits, with temperature increases not exceeding 5.5 °C.

Influence of Class V preparation on in vivo temperature rise in anesthetized human pulp during exposure to a Polywave® LED light curing unit

ObjectiveThis in vivo study evaluated pulp temperature (PT) rise in human premolars having deep Class V preparations during exposure to a light curing unit (LCU) using selected exposure modes (EMs). MethodsAfter local Ethics Committee approval, intact first premolars (n=8) requiring extraction for orthodontic reasons, from 8 volunteers, received infiltrative and intraligamental anesthesia and were isolated using rubber dam. A minute pulp exposure was attained and sterile probe from a wireless, NIST-traceable, temperature acquisition system was inserted into the coronal pulp chamber to continuously monitor PT (°C). A deep buccal Class V preparation was prepared using a high speed diamond bur under air-water spray cooling. The surface was exposed to a Polywave® LED LCU (Bluephase 20i, Ivoclar Vivadent) using selected EMs, allowing 7-min span between each exposure: 10-s in low (10-s/L), 10-s (10-s/H), 30-s (30-s/H), or 60-s (60-s/H) in high mode; and 5-s-Turbo (5-s/T). Peak PT values and PT increases over physiologic baseline levels (ΔT) were subjected to 1-way, repeated measures ANOVAs, and Bonferroni’s post-hoc tests (α=0.05). Linear regression analysis was performed to establish the relationship between applied radiant exposure and ΔT. ResultsAll EMs produced higher peak PT than the baseline temperature (p<0.001). Only 60-s/H mode generated an average ΔT of 5.5°C (p<0.001). A significant, positive relationship was noted between applied radiant exposure and ΔT (r2=0.8962; p<0.001). SignificanceIn vivo exposure of deep Class V preparation to Polywave® LED LCU increases PT to values considered safe for the pulp, for most EMs. Only the longest evaluated EM caused higher PT increase than the critical ΔT, thought to be associated with pulpal necrosis.

The effect of Light Emitting Diode and Sandwich technique on Pulp Temperature during Polymerization of Composite resin

This in vitro study evaluated the effect of glass ionomer liner in limiting temperature rise during composite curing with Light Emitting Diode (LED cure unit) compare it with Conventional visible light-cure lamp.Twenty sound upper premolar teeth were used &amp; on the buccal and palatal surfaces of them, a standardized class V cavity was prepared, 1mm occlusal to the cemento-enamel junction. Cavity dimensions of occluso-gingival height 1.5mm, mesio-distal width of 3mm. The depth of the cavity was 2mm and was calibrated by measuring with a pre marked periodontal probe. The teeth were randomly divided into four groups according to the cure mode and filling teqnique. Each group consist of 5 teeth (10 cavities); Group I; each cavity filled with 2mm (micro-hybrid resin composite) and cured with Quartz Tungsten Halogen light unit (QTH), Group II; the same as Group I but cured with Light Emitting Diod (LED cure unit), Group III; each cavity filled with glass ionomer lining of 0.5mm and 1.5mm (micro-hybrid resin composite), and cured with Quartz Tungsten Halogen light unit (QTH), &amp; Group IV; each cavity filled with glass ionomer lining of 0.5mm and 1.5mm (micro-hybrid resin composite) but cured with Light Emitting Diod (LED cure unit). Temperature was measured before light curing of the composite resin &amp; immediately after it. Then the Temperature was measured by a type K thermocouple.The results revealed that there were significant differences between the groups at p&lt;0.01 with in favor of the group filled with composite resin &amp; cured with LED with glass ionomer lining.The use of sandwich restorations with LED curing unit produced lesser temperature degrees toward the pulp space.

A cool response-The influence of ambient temperature on capillary refill time.

To describe the effect of low ambient temperature on skin temperature and capillary refill (CR) time in forehead, sternum and finger pulp. An observational, nonrandomized experimental study on 15 healthy subjects (6 females) in a cold room (8°C). Outcome measures were skin temperature and quantified CR test after application of a standardized blanching pressure (9 N/cm2 ) using digital photographic polarization spectroscopy to generate CR times. The finger pulp showed marked temperature fall and prolonged CR times (>10 seconds). The CR registrations of the forehead and sternum were more comparable to curves observed in a control material at room temperature, and skin temperature falls were less marked. CR times were not prolonged in forehead measurements. At the sternum, some individuals showed CR times beyond guideline recommendations despite only a marginal reduction in skin temperature. Low ambient temperature is a strong independent factor for CR time at peripheral sites. Reservation about sternum as a site of measurement is warranted since cold provocation produced prolonged CR times in some individuals. We found that the forehead is the most thermostable of the 3 sites and thus the preferred site to avoid ambient temperature artifact in measuring CR time.

In vitro study: conventional vs. laser (Er,Cr:YSGG) subgingival scaling and root planing; morphologic analysis and efficiency of calculus removal using macroscopic, SEM and laser scanning

Many ways and techniques were used for subgingival calculus removal to be achieved, from scaling and root planning closed and opened technique, manual curettes, air abrasives, and finally dental lasers machines. In this study, we will compare conventional ultra-sonic scaling and curettes to two laser groups using Er,Cr:YSGG 2780 nm. One group (LASER) using 25 mJ, 50 Hz, 50 μs pulse duration, 20 ms pulse period, 1.25 W average power, 500 W peak power W/A:80%/10%, and other group (LASER+) using manufacturer instructions: 47 mJ, 75 Hz, 50 μs pulse duration, 3.5 W average power, 940 W peak power, W/A 40%, 20%. Fifteen extracted teeth that have subgingival calculus was used in each group. Showed no statistical difference between time in three groups, there was a statistical difference concerning the amount of calculus, group laser + showed least amount of calculus remaining. Root roughness showed statistical significant, the laser + treatment shows significant higher root values than the laser treatment as well as compared to conventional treatment. Laser scanning showed no statistical difference concerning root roughness. SEM showed conventional group with roughness and smear layer, laser group showed the most smooth surface, laser + showed the most rough surface. Er,Cr:YSGG is effective and efficient to remove subgingival calculus and safe to the pulp specially the parameters of laser group, as well as it is benefits concerning smear layer removal, bactericidal effect, promoting fibroblasts attachment and mostly few raise in pulpal temperature as shown in other studies. Amount of water spray is considered to be the most important factor due to it is effect on roughness and root morphology.

Efficiency of Er:YAG laser in debonding of porcelain laminate veneers by contact and non-contact laser application modes (in vitro study).

To determine the efficiency of debonding porcelain laminate veneers (PLV) by using several laser parameters and two different application modes of Er:YAG laser [contact (CM) and non-contact (NCM)], by verification of the consumed PLV debonding time and the changes in dental pulp temperature. Forty extracted non-carious human maxillary premolars were prepared for receiving PLV. Sixteen of them were divided into two groups, each of them comprised eight samples based on the application mode; group A with NCM, and group B with CM. Veneers of both groups were debonded by the same laser parameters (360 mJ, 15 Hz) during loading of a 15 N force on specially fabricated veneer cervical margins. The primary results showed that the NCM was more efficient, thus, additional groups (C, D, and E) of the same mode and number of samples were tested with different laser parameters of energy and frequency; group C (400 mJ, 10 Hz), group D (270 mJ, 15 Hz), group E (300 mJ, 10 Hz). The failure mode was determined and classified for the debonded samples of all groups. All veneers were debonded and samples of the NCM group had considerably lower debonding time (12.6 seconds) than the CM samples (96.3 seconds), however, higher changes of temperature in NCM (4.2°C) than in CM were observed (2.9°C). The failure mode of samples was either type 1 or 3. Er:YAG laser is an effective tool in debonding PLVs. The NCM application mode was more efficient in reducing debonding time than CM application mode but with a higher change in pulp temperature. Investigating the efficacy of Er:YAG laser as a non-invasive particle technique for debonding of failed or malpositioned of porcelain laminated veneers.

Thermal Scanning of Dental Pulp Chamber by Thermocouple System and Infrared Camera during Photo Curing of Resin Composites.

Introduction:Due to thermal hazard during composite restorations, this study was designed to scan the pulp temperature by thermocouple and infrared camera during photo polymerizing different composites. Methods and Materials:A mesio-occlso-distal (MOD) cavity was prepared in an extracted tooth and the K-type thermocouple was fixed in its pulp chamber. Subsequently, 1 mm increment of each composites were inserted (four composite types were incorporated) and photo polymerized employing either LED or QTH systems for 60 sec while the temperature was recorded with 10 sec intervals. Ultimately, the same tooth was hemisected bucco-lingually and the amalgam was removed. The same composite curing procedure was repeated while the thermogram was recorded using an infrared camera. Thereafter, the data was analyzed by repeated measured ANOVA followed by Tukey’s HSD Post Hoc test for multiple comparisons (α=0.05). Results:The pulp temperature was significantly increased (repeated measures) during photo polymerization (P=0.000) while there was no significant difference among the results recorded by thermocouple comparing to infrared camera (P>0.05). Moreover, different composite materials and LCUs lead to similar outcomes (P>0.05). Conclusion:Although various composites have significant different chemical compositions, they lead to similar pulp thermal changes. Moreover, both the infrared camera and the thermocouple would record parallel results of dental pulp temperature.

Evaluation of the effect of diode laser for debonding ceramic brackets on nanomechanical properties of enamel

The heat from laser can lead to the destruction of organic components of enamel and consequently changes in the mechanical properties of enamel. The purpose of this study was to evaluate the effect of diode laser on the nanomechanical properties of enamel in the process of debonding the ceramic brackets. In This in vitro study Eighteen ceramic brackets were bonded on the intact premolars in 3 groups of 6 (one control and two study groups). To debond the brackets in the study groups, laser diode was used for 3 s with 1W and 3W power. Shear bond strength and adhesive remnant index were recorded for all groups. Hardness and elastic modulus were measured in 1-31 μ depth from enamel surface in each debonded area. Analysis of variance was used for determining the difference in shear bond strength (SBS), hardness, and elastic modulus and was followed by post hoc Tukey's honest significant difference test. One-sample t-test was used to compare the changes in the pulp temperature with the standard threshold (5.5°C). The significance level was set at %5 in this study. SBS was significantly greater in the control group compared to the study groups. There was no significant difference in the average of hardness and elastic modulus of enamel between the groups. Pulp temperature elevation in the study groups was significantly < 5.5°C (P = 0.000). The diode laser with either 1W or 3W power for 3 s is effective in debonding the ceramic brackets without any detrimental effect on the pulp or mechanical properties of enamel. In regard to the pulp health, the 1W power laser is rather recommended for debonding the ceramic brackets than the 3W laser power.

Pulpal Temperature Rise: Evaluation after Light Activation of Newer Pulp-Capping Materials and Resin Composite.

Background:To evaluate temperature changes in pulp chamber during light activation of newer pulp- capping materials and composite resin using light-emitting diode.Materials and Methods:A standardized Class I cavity was prepared in 80 extracted, intact, noncarious mandibular first molars, keeping remaining dentin thickness of 0.5 mm. The teeth were divided into four groups of 20 teeth each. Following this, apical third of the mesial root of each tooth was cut and a K type thermocouple attached to digital thermometer was inserted into pulp chamber from the sectioned mesial root. Whole assembly with teeth was suspended in water bath with constant temperature at 37°C. The previously divided teeth in four groups, were lined with Calcimol LC (Group A), Activa (Group B), TheraCal LC (Group C), and Ionoseal (Group D), followed by 3 increments of Filtek Z350 × T universal restorative. The temperature rise following light activation of pulp-capping material, bonding agent, and composite was noted.Results:The temperature rise in the pulp chamber after light activation of Activa was highest among all pulp-capping materials, followed by teeth lined with Calcimol LC, Ionoseal, and least in teeth with TheraCal LC.Conclusions:Temperature rise in the pulp chamber after light activation of newer pulp-capping materials and composite was below critical threshold for irreversible pulpal damage. Among all the pulp-capping materials, TheraCal LC showed lowest temperature rise in pulp chamber.

Studies on quality of southern highbush blueberry cultivars: effects of pulp temperature, impact and hydrocooling

Studies on quality of southern highbush blueberry cultivars: effects of pulp temperature, impact and hydrocooling

Effect of Light Activation of Pulp-Capping Materials and Resin Composite on Dentin Deformation and the Pulp Temperature Change.

To analyze the effect of pulp-capping materials and resin composite light activation on strain and temperature development in the pulp and on the interfacial integrity at the pulpal floor/pulp-capping materials in large molar class II cavities. Forty extracted molars received large mesio-occlusal-distal (MOD) cavity bur preparation with 1.0 mm of dentin remaining at the pulp floor. Four pulp-capping materials (self-etching adhesive system, Clearfil SE Bond [CLE], Kuraray), two light-curing calcium hydroxide cements (BioCal [BIO], Biodinâmica, and Ultra-Blend Plus [ULT], Ultradent), and a resin-modified glass ionomer cement- (Vitrebond [VIT], 3M ESPE) were applied on the pulpal floor. The cavities were incrementally restored with resin composite (Filtek Z350 XT, 3M ESPE). Thermocouple (n=10) and strain gauge (n=10) were placed inside the pulp chamber in contact with the top of the pulpal floor to detect temperature changes and dentin strain during light curing of the pulp-capping materials and during resin composite restoration. Exotherm was calculated by subtracting postcure from polymerization temperature (n=10). Interface integrity at the pulpal floor was investigated using micro-CT (SkyScan 1272, Bruker). The degree of cure of capping materials was calculated using the Fourier transform infrared and attenuated total reflectance cell. Data were analyzed using one-way analysis of variance followed by the Tukey test (α=0.05). Pulpal dentin strains (μs) during light curing of CLE were higher than for other pulp-capping materials ( p<0.001). During resin composite light activation, the pulpal dentin strain increased for ULT, VIT, and CLE and decreased for BIO. The pulpal dentin strain was significantly higher during pulp-capping light activation. The temperature inside the pulp chamber increased approximately 3.5°C after light curing the pulp-capping materials and approximately 2.1°C after final restoration. Pulp-capping material type had no influence temperature increase. The micro-CT showed perfect interfacial integrity after restoration for CLE and ULT; however, gaps were found between BIO and pulpal floor in all specimens. BIO had a significantly lower degree of conversion than ULT, VIT, and CLE. Light curing of pulp-capping materials caused deformation of pulpal dentin and increased pulpal temperature in large MOD cavities. Shrinkage of the resin composite restoration caused debonding of BIO from the pulpal floor.

Low-temperature performance of cationic collector undecyl propyl ether amine for ilmenite flotation

When conventional anionic collectors (e.g., fatty acids) are used in flotation separation of ilmenite and titanaugite, a high flotation temperature (>293K) is generally required. However, it is crucial to develop low-temperature flotation processes for use in cold regions. This study demonstrates that the cationic collector undecyl propyl ether amine (UPEA) has outstanding collecting ability, selectivity, and low-temperature performance for ilmenite ore flotation. Various important factors that influence flotation performance, such as pH, UPEA dosage, and pulp temperature, were investigated by microflotation tests. Compared with a higher temperature (295K), superior flotation recovery was obtained by closed-circuit flotation of actual ore at 279K. Zeta potential measurements illustrated that large amounts of UPEA were selectively adsorbed on the ilmenite surface. Thermodynamic calculations and Fourier transform infrared analyses showed that adsorption of UPEA onto both mineral surfaces involved a physisorption process. Moreover, increasing the thermodynamic energy of UPEA molecules diminished interactions between UPEA and the minerals, resulting in decreased adsorption of UPEA with increasing temperature, as confirmed by adsorption analysis. The excellent low-temperature flotation performance of UPEA is consistent with the energy conservation policy of China, and the use of UPEA should be promoted in cold regions. This work provides new insights into the efficient separation of ilmenite from titanaugite at low temperatures.

Heat transfer and drying kinetics of tomato pulp processed by cast-tape drying

ABSTRACTCast-tape drying (CTD) is a process to dehydrate suspensions. This study evaluated the influence of heat source and forced air convection on the drying rate and temperature of tomato pulp during CTD. To this, a pulp thin layer was spread on a flexible support with its lower surface in direct contact with a heat source. Similar drying rates and evaporative capacities were observed for both flexible supports and heating media. Steam simplifies the temperature control and equipment construction. CTD is a suitable process for producing dried tomato pulp in short drying times, resulting from high evaporative capacity.

Artificial fruit for monitoring the thermal history of horticultural produce in the cold chain

There is a need for more realistic monitoring of fruit pulp temperature history throughout the cold chain at a higher spatial resolution inside the cargo. Particularly solutions that are easy to install in a commercial setting are required. For this purpose, a novel kind of fruit simulator – an artificial fruit – has been designed, manufactured and tested. Using a biomimetic approach, it was engineered specifically to match the thermal response of real fruit as close as possible. The artificial fruit is composed out of a thin plastic shell, which mimics the exterior size, shape, surface texture and color of the fruit of interest. This shell is filled with a mixture that has similar thermal properties as real fruit as it is basically composed out of the same components. Two self-powered data loggers with a built-in sensor are integrated in the artificial fruit. These different components of the artificial fruit were combined successfully into a manufactured prototype. The thermal response of an artificial apple fruit during cooling was evaluated against that of 10 real apples. The cooling time of the artificial fruit was within 5% of that of the real fruits. The artificial fruit also had a more accurate thermal response than that of water-filled fruit simulators, with which differences up to 16% were found. The uniformity in size, shape and sensor location of the artificial fruit also enables it to measure fruit pulp temperature in a much more repeatable manner than with real fruit. A particular advantage of the artificial fruit is that it can be packed directly with the fresh produce in a commercial setting, by which multiple locations inside the cargo can easily be monitored. This novel sensor system thus provides an improved method to identify heterogeneities in cargo cooling, and associated quality issues. The artificial fruit is especially of interest for monitoring fruit pulp in precooling facilities, cold stores, ripening facilities and refrigerated containers.

Modern high powered led curing lights and their effect on pulp chamber temperature of bulk and incrementally cured composite resin.

Pulpal temperature changes induced by modern high powered light emitting diodes (LEDs) are of concern when used to cure composite resins. This study showed an increase in pulp chamber temperature with an increase in power density for all light cure units (LCU) when used to bulk cure composite resin. Amongst the three LEDs tested, the Elipar Freelight-2 recorded the highest temperature changes. Bulk curing recorded a significantly larger rise in pulp chamber temperature change than incrementally cured resin for all light types except for the Smartligh PS. Both the high powered LED and the conventional curing units can generate heat. Though this temperature rise may not be sufficient to cause irreversible pulpal damage, it would be safer to incrementally cure resins.