Stem Cell and Exosome Therapy in Pulmonary Hypertension

Pulmonary hypertension is a rare and progressive illness with a devastating prognosis. Promising research efforts have advanced the understanding and recognition of the pathobiology of pulmonary hypertension. Despite remarkable achievements in terms of improving the survival rate, reducing disease progression, and enhancing quality of life, pulmonary arterial hypertension (PAH) is not completely curable. Therefore, an effective treatment strategy is still needed. Recently, many studies of the underlying molecular mechanisms and technological developments have led to new approaches and paradigms for PAH treatment. Management based on stem cells and related paracrine effects, epigenetic drugs and gene therapies has yielded prospective results for PAH treatment in preclinical research. Further trials are ongoing to optimize these important insights into clinical circumstances.

External validation of risk prediction platforms for pancreatic fistula after pancreatoduodenectomy using nomograms and artificial intelligence

Purpose@#Postoperative pancreatic fistula (POPF) is a life-threatening complication following pancreatoduodenectomy (PD).We previously developed nomogram- and artificial intelligence (AI)-based risk prediction platforms for POPF after PD. This study aims to externally validate these platforms. @*Methods@#Between January 2007 and December 2016, a total of 1,576 patients who underwent PD in Seoul National University Hospital, Ilsan Paik Hospital, and Boramae Medical Center were retrospectively reviewed. The individual risk scores for POPF were calculated using each platform by Samsung Medical Center. The predictive ability was evaluated using a receiver operating characteristic curve and the area under the curve (AUC). The optimal predictive value was obtained via backward elimination in accordance with the results from the AI development process. @*Results@#The AUC of the nomogram after external validation was 0.679 (P < 0.001). The values of AUC after backward elimination in the AI model varied from 0.585 to 0.672. A total of 13 risk factors represented the maximal AUC of 0.672 (P < 0.001). @*Conclusion@#We performed external validation of previously developed platforms for predicting POPF. Further research is needed to investigate other potential risk factors and thereby improve the predictability of the platform.

Effects of thickness and background on the masking ability of high -trasnlucent zirconias

Purpose@#The purpose of this study was to compare and evaluate the masking ability of three types of high translucent zirconia according to the various thicknesses and backgrounds. @*Materials and Methods@#Using three types of high-translucency zirconia (Ceramill zolid fx white, Ceramill zolid ht+ white, Ceramill zolid ht+ preshade A2), 10 cylindrical specimens were fabricated in 10mm diameter and each with four thicknesses (0.6 mm, 1.0 mm, 1.5 mm, 2.0 mm), respectively by CAD/CAM method. The background was 10 mm in diameter and 10 mm in thickness. A1, A2, A3 flowable resin backgrounds, blue-colored core resin background, and Ni-Cr alloy background were prepared, and black, white backgrounds provided by the spectrophotometer manufacturer (x-rite, Koblach, Austria) were used. zirconia specimens and the background specimen were stacked to measure L, a*, b* with Spectrophotometer (Color i5, x-rite, Koblach, Austria) and the ∆E value with the other background is calculated. The Calculated mean ∆E values were compared based on perceptibility threshold 1.0 and acceptability threshold 3.7. Nonparametric tests such as Kruskal-Wallis test were performed to verify statistical significance (α = 0.05). @*Results@#There was a significant difference in the mean ∆E value according to the zirconia type, background and thickness change (P = 0.000). @*Conclusion@#According to the results of this study, the pre-colored high-translucent zirconia can obtain the desired zirconia shade when it is restored on teeth, composite resins, and abutments except for the blue resin core.

Effect of tack cure time on polymerization shrinkage of dual-cure resin cement

When luting indirect restorations with dual-cure resin cement (DCRC), excess cement can be easily removed by performing tack cure of DCRC for a few seconds. The purpose of this study was to evaluate whether different tack cure times affect polymerization shrinkage (PS) of the selected DCRC. One dual-cure resin cement (G-CEM LinkAce, GC) was used for measuring PS in light-cure (LC group), self-cure (SC group), and two tack-cure modes. In the first tack-cure subgroup, tack cure was performed for 1, 2, 3, and 5 seconds, followed by light cure after 2 minutes of remnant removal time in each case (TC-LC groups). In the other tack-cure subgroup, tack cure was performed for the same lengths of time, but followed by self-cure in each case (TC-SC groups). PS was measured by a modified bonded disc method for 1,800 seconds. One-way analysis of variance followed by Duncan’s post hoc test was used to determine any statistically significant differences among the test groups (α = 0.05). When the DCRC was selfcured after tack cure, PS was significantly lower than when it was only self-cured (p 0.05). When the DCRC was light-cured, PS was not affected by tack cure or tack cure time (p > 0.05). Therefore, tack cure within 5 seconds did not negatively affect the final PS when the DCRC was light-cured after cement remnant removal.

Tensile bond strength of chairside reline resin to denture bases fabricated by subtractive and additive manufacturing / 대한치과보철학회지

Purpose@#The purpose of this study was to compare and evaluate the tensile bond strength of chairside reline resin to denture base resin fabricated by different methods (subtractive manufacturing, additive manufacturing, and conventional heat-curing). @*Materials and methods@#Denture base specimens were fabricated as cuboid specimens with a width of 25 mm × length 25 mm × height 3 mm by subtractive manufacturing (VITA VIONIC BASE), additive manufacturing (NextDent Base) and conventional heat-curing (Lucitone 199). After storing the specimens in distilled water at 37°C for 30 days and drying them, they were relined with polyethyl methacrylate (PEMA) chairside reline resin (REBASE II Normal). The subtractive and additive manufacturing groups were set as the experimental group, and the heat-curing group was set as the control group. Ten specimens were prepared for each group. After storing all bound specimens in distilled water at 37°C for 24 hours, the tensile bond strength between denture bases and chairside reline resin was measured by a universal testing machine at a crosshead speed of 10 mm/min. The fracture pattern of each specimen was analyzed and classified into adhesive failure, cohesive failure, and mixed failure. Tensile bond strength, according to the fabrication method, was analyzed by 1-way ANOVA and Bonferroni’s method (α =.05). @*Results@#Mean tensile bond strength of the heat-curing group (2.45 ± 0.39 MPa) and subtractive manufacturing group (2.33 ± 0.39 MPa) had no significant difference (P>.999). The additive manufacturing group showed significantly lower tensile bond strength (1.23 ± 0.36 MPa) compared to the other groups (P<.001). Most specimens of heat-curing and subtractive manufacturing groups had mixed failure, but mixed failure and adhesive failure showed the same frequency in additive manufacturing group. @*Conclusion@#The mean tensile bond strength of the subtractive manufacturing group was not significantly different from the heat-curing group. The additive manufacturing group showed significantly lower mean tensile bond strength than the other two groups.

Marginal and internal fit of 3D printed provisional crowns according to build directions

PURPOSE@#. This study aimed to fabricate provisional crowns at varying build directions using the digital light processing (DLP)-based 3D printing and evaluate the marginal and internal fit of the provisional crowns using the silicone replica technique (SRT). MATERIALS AND METHODS. The prepared resin tooth was scanned and a single crown was designed using computer-aided design (CAD) software. Provisional crowns were printed usinga DLP-based 3D printer at 6 directions (120°, 135°, 150°, 180°, 210°, 225°) with 10 crowns in each direction. In total, sixty crowns were printed. To measure the marginal and internal fit, a silicone replica was fabricated and the thickness of the silicone impression material was measured using a digital microscope. Sixteen reference points were set and divided into the following 4 groups: marginal gap (MG), cervical gap (CG), axial gap (AG),and occlusal gap (OG). The measurements were statistically analyzed using one-way ANOVA and Dunnett T3. @*RESULTS@#MG, CG, and OG were significantly different by build angle groups (P<.05). The MG and CG were significantly larger in the 120° group than in other groups. OG was the smallest in the 150° and 180° and the largest in the 120° and 135° groups. @*CONCLUSION@#The marginal and internal fit of the 3D-printed provisional crowns can vary depending on the build angle and the best fit was achieved with build angles of 150°and 180°

Clinical study on screw loosening in dental implant prostheses: a 6-year retrospective study

Objectives@#In this study, we determined the incidence and pattern of screw loosening in patients who received dental implants. @*Materials and Methods@#Patients who received implants between January 2008 and October 2013 and completed their prosthetic rehabilitation were evaluated for the incidence, frequency, and onset of screw loosening using dental charts and radiographs. The association between each factor and screw loosening was analyzed using the chi-square test and a multivariate analysis with binary logistic regression models (P<0.05). @*Results@#Total 1,928 implants were placed in 837 patients (448 males, 389 females), whose follow-up period after loading varied from 0.25 to 70 months (mean period, 31.5 months). Screw loosening occurred in 7.2% of implants. Most cases occurred less than six months after loading. Among those, 22.3% experienced recurrent screw loosening. Screw loosening was most common in the molar region (8.5%) and frequently associated with an implant diameter of ≥5 mm (14.2%). External implant–abutment connections (8.9%) and screw-retained implant prostheses (10.1%) showed higher incidence of problems than internal implant–abutment connections and cement-retained implants, respectively. Screw loosening was most common in implant prostheses with single crowns (14.0%). @*Conclusion@#Within the limits of the current study, we conclude that the incidence of screw loosening differs significantly according to the position of implant placement, the type of implant and manufacturer, implant diameter, the type of implant–abutment connection, the type of retention in the implant prosthesis, and the type of implant prosthesis.

Treatment of intramuscular lipoma of tongue with enveloped mucosal flap design: a case report and review of the literature / 대한악안면성형재건외과학회지

Background@#Lipomas are benign soft tissue neoplasms of mature adipose tissue commonly occurring in the trunk or extremities. But, intraoral lipomas are rare entities which may be only noticed during routine dental examinations. Especially intramuscular lipomas on the tongue have been reported very rarely. In this study, we report a case of intramuscular lipoma on tongue, with a review of the literature from 1978 to 2019, providing data on age, gender, location, presenting symptoms, size, surgical methods, and recurrence.Case presentationA case of intramuscular lipoma occurring in tongue region in a 65-year-old male is reported. Surgical excision is the mainstay of treatment for the lesion. In order to decrease the deformity and discomfort after the excision, we tried to modify surgical technique using enveloped mucosal flap. This technique provided more comfortable healing procedure on the operative site without recurrence. @*Conclusion@#This is a rare case of large intramuscular lipoma on tongue. Surgical excision with enveloped mucosal flap design was performed to diminish postoperative raw surface and discomfort and a 24-month follow-up showed excellent healing without any recurrence. A case of intramuscular lipoma on tongue and relevant literature reviews are presented in this study.

Treatment of intramuscular lipoma of tongue with enveloped mucosal flap design: a case report and review of the literature / 대한악안면성형재건외과학회지

Background@#Lipomas are benign soft tissue neoplasms of mature adipose tissue commonly occurring in the trunk or extremities. But, intraoral lipomas are rare entities which may be only noticed during routine dental examinations. Especially intramuscular lipomas on the tongue have been reported very rarely. In this study, we report a case of intramuscular lipoma on tongue, with a review of the literature from 1978 to 2019, providing data on age, gender, location, presenting symptoms, size, surgical methods, and recurrence.Case presentationA case of intramuscular lipoma occurring in tongue region in a 65-year-old male is reported. Surgical excision is the mainstay of treatment for the lesion. In order to decrease the deformity and discomfort after the excision, we tried to modify surgical technique using enveloped mucosal flap. This technique provided more comfortable healing procedure on the operative site without recurrence. @*Conclusion@#This is a rare case of large intramuscular lipoma on tongue. Surgical excision with enveloped mucosal flap design was performed to diminish postoperative raw surface and discomfort and a 24-month follow-up showed excellent healing without any recurrence. A case of intramuscular lipoma on tongue and relevant literature reviews are presented in this study.

Antioxidant effects of kimchi supplemented with black raspberry during fermentation protect against liver cirrhosis-induced oxidative stress in rats

BACKGROUND/OBJECTIVES: Oxidative stress is a major effector of various diseases; accordingly, antioxidants are frequently ingested in order to prevent or alleviate disease symptoms. Kimchi contains various natural antioxidants, and it is known that the functional activity varies depending on the ingredients and fermentation state. Black raspberries (BR) contain various bioactive compounds with antioxidant effects. This study investigated the antioxidant and liver-protection effects of kimchi supplemented with black raspberry juice powder (BJP). MATERIALS/METHODS: BJP-added kimchi (BAK; at 0.5%, 1%, and 2% concentrations of BJP) and control (without BJP) were prepared and fermented at 4℃ for 4 weeks. Changes in the antioxidant effects of BAK during fermentation were investigated. In addition, the protective activity of BAK against oxidative stress was investigated in a liver cirrhosis-induced animal model in vivo. RESULTS: BAK groups showed the acidity and pH of optimally ripened (OR) kimchi at 2 weeks of fermentation along with the highest lactic acid bacterial counts. Additionally, BAK groups displayed a higher content of phenolic compounds and elevated antioxidant activities relative to the control, with the highest antioxidant effect observed at 2 weeks of fermentation of OR 1% BAK. After feeding the OR 1% BAK to thioacetamide-induced liver cirrhosis rats, we observed decreased glutamate oxaloacetate transaminase and glutamate pyruvate transaminase activities and elevated superoxide dismutase activity. CONCLUSIONS: These findings showed that the antioxidant effects of OR BAK and feeding of OR 1% BAK resulted in liver-protective effects against oxidative stress.

Comparison of marginal and internal discrepancies of zirconia crowns fabricated by various digital scan methods / 대한치과재료학회지

In this study, marginal and internal discrepancies of zirconia crowns fabricated with the CAD/CAM (computer aided design

Comparative evaluation of marginal and internal fit of metal copings fabricated by various CAD/CAM methods / 대한치과보철학회지

PURPOSE: The purpose of the present study was to compare the accuracy of four different metal copings fabricated by CAD/CAM technology and to evaluate clinical effectiveness. MATERIALS AND METHODS: Composite resin tooth of the maxillary central incisor was prepared for a metal ceramic crown and duplicated metal die was fabricated. Then scan the metal die for 12 times to obtain STL files using a confocal microscopy type oral scanner. Metal copings with a thickness of 0.5 mm and a cement space of 50 µm were designed on a CAD program. The Co-Cr metal copings were fabricated by the following four methods: Wax pattern milling & Casting (WM), Resin pattern 3D Printing & casting (RP), Milling & Sintering (MS), Selective laser melting (SLM). Silicone replica technique was used to measure marginal and internal discrepancies. The data was statistically analyzed with One-way analysis of variance and appropriate post hoc test (Scheffe test) (α=.05). RESULTS: Mean marginal discrepancy was significantly smaller in the Group WM (27.66 ± 9.85 µm) and Group MS (28.88 ± 10.13 µm) than in the Group RP (38.09 ± 11.14 µm). Mean cervical discrepancy was significantly smaller in the Group MS than in the Group RP. Mean axial discrepancy was significantly smaller in the Group WM and Group MS then in the Group RP and Group SLM. Mean incisal discrepancies was significantly smaller in the Group RP than in all other groups. CONCLUSION: The marginal and axial discrepancies of the Co-Cr coping fabricated by the Wax pattern milling and Milling/Sintering method were better than those of the other groups. The marginal, cervical and axial fit of Co-Cr copings in all groups are within a clinically acceptable range.

High dairy products intake reduces osteoporosis risk in Korean postmenopausal women: A 4 year follow-up study

BACKGROUND/OBJECTIVES: The aim of this study was to identify the effect of dairy products, milk and yogurt on osteoporosis incidence among Korean postmenopausal women using prospective cohort data. MATERIALS/METHODS: Between 2001 and 2003, 10,038 participants were recruited in rural and urban areas for a baseline examination of a community-based cohort study. Of those, 1,573 postmenopausal women (aged 40–69 years at baseline) were eligible for the present study. Intakes of dairy products, milk, and yogurt were assessed using a validated semi-quantitative food frequency questionnaire. The speed of sound at the radius and tibia were measured using a quantitative ultrasound device and osteoporosis was defined based on the WHO criteria (T-score ≤−2.5). RESULTS: During the 4-years follow-up study, the cumulative incidence of osteoporosis was 18.4% (273 cases) in the radius and 33.6% (407 cases) in the tibia. The subjects with higher frequency of dairy product consumption showed a decreased risk of radius osteoporosis after adjusting for potential confounders [hazard ratio (HR) = 0.51, 95% confidence interval (CI): 0.33–0.80 for >1 time/day vs. non consumer; P for trend = 0.0027]. Similarly, high frequency of milk and yogurt consumption had a protective effect on radius osteoporosis risk [milk: HR = 0.60, 95% CI: 0.42–0.87 for >5–6 times/week vs. non consumer (P for trend = 0.0130), yogurt: HR = 0.51, 95% CI: 0.30–0.85 for > 5–6 times/week vs. non consumer (P for trend = 0.0167)]. However, high dairy products consumption was not related with tibia osteoporosis. CONCLUSIONS: This study suggests that daily intake of dairy products could potentially reduce radius osteoporosis incidence among Korean postmenopausal women.

Retrospective study on marginal bone resorption around immediately loaded implants / 대한치과보철학회지

PURPOSE: Patients who treated implant immediate loading within a week after implant placement at Wonkwang University Dental Hospital Implant Center were evaluated marginal bone resorption. These retrospective analyses are intended to reinforce the clinical evidence for the implant immediate loading. MATERIALS AND METHODS: Medical history and radiographic data were investigated, which were the patients' who treated implant immediate loading and restoration with provisional prostheses between January 2005 and June 2016, at Wonkwang University Dental Hospital Implant Center. Total number of implants was 70, marginal bone resorption was measured according to implant length, diameter and connection type. To measure marginal bone resorption, periapical radiographs were taken when the implants were placed and after 6 month. Statistical analysis was done in Mann-whitney U test and Kruskal-wallis test with SPSS 22.0 software (P < .05). RESULTS: Mean marginal bone resorption around immediately loaded implants according to implant connection type was shown 1.24 ± 0.72 mm in internal hexagon connection type and 1.73 ± 1.27 mm in external hexagon connection type. There was no statically significant difference in marginal bone resorption with implant length and diameter. CONCLUSION: Implants with immediated loading in internal hexagon connection type showed less marginal bone resorption significantly than in external hexagon connection type.

The Effect of Maté Extract on Body Weight and Fat Reduction in Obese Women: A Randomized Placebo-controlled Clinical Trial

BACKGROUND: This study was performed to investigate the effects of Maté extract on body weight and fat content in obese women [25.0 kg/m² ≤body mass index (BMI) <30 kg/m²] aged 20-65 years after 6 weeks of its administration. METHODS: The randomized, double-blind, placebo-controlled study was conducted in 33 women. Participants took the supplement, either 2 Maté tablets or 2 placebo tablets, twice daily before meals for 6 weeks. Body weight, body mass index (BMI), waist circumference (WC), and various safety parameters were monitored. Body composition was measured by dual-energy X-ray absorptiometry at baseline and after 6 weeks.

Development of a Smartphone Application for 4th-6th Grade Elementary Students Aimed to Prevent Childhood Obesity

BACKGROUND: There is high interest in a new approach to improve children's lifestyle habits in order to prevent childhood obesity. A smartphone application (app) is a new technology platform that can be used to prevent childhood obesity. METHODS: The key messages for healthy eating habits and physical activities were selected by experts in nutrition, physical activity, and psychology and were adjusted for use in elementary school students. Gamification techniques were used to increase app user engagement. A total of 249 students in grades 4-6 were asked to rate their satisfaction for the app after 4 weeks of use. RESULTS: The main menu of "HAPPY ME" was composed of user profile, "EVERYDAY QUEST," exercise diary, diet diary, settings, and notifications. The app users were asked to complete 6-9 daily missions regarding healthy eating habits and physical activities through "EVERYDAY QUEST." The mean satisfaction scores for each variable were distributed from 3.6 to 4.0 points, and most of the students responded that they would continue to use the app (4.0 points). CONCLUSION: We developed a smartphone app (HAPPY ME) for 4th-6th grade elementary students aimed to provide educational information about healthy eating habits and physical activities in order to prevent childhood.

Retrospective study on marginal bone loss around maxillary anterior implants with or without bone graft / 대한치과보철학회지

PURPOSE: This study is to evaluate the clinical significance of implantation with simultaneous bone graft by comparing the marginal bone loss around maxillary anterior implants with or without bone graft MATERIALS AND METHODS: Patients treated with implant-retained restorations on maxillary anterior region at Implant Center, Dental Hospital, Wonkwang University between June 2011 and May 2014 were included in this study. Date of implant placement, implant diameter, implant length, implant-abutment connection type and whether the bone graft was done were investigated. The patient's periapical radiographs taken immediately after implantation and at the most recent visit were compared. Marginal bone loss was measured using Emago advanced v5.6 program (Oral diagnostic systems, Amsterdam, Netherlands). Statistical analysis was done in independent t-test by using SPSS 22.0 program. RESULTS: As a result of observing on 83 implants (without bone graft: 44, with bone graft: 39) of 52 patients for 6 - 45 months (average: 18.4 months), implants without bone graft showed 1.42 ± 0.42 mm, implants with bone graft showed 1.28 ± 0.45 mm of marginal bone loss. CONCLUSION: In limitations of this study, implants with simultaneous bone graft had significantly less marginal bone loss than implants without bone graft.

Acceptability and Feasibility of a Smartphone Application for 5th, 6th Grade Elementary Students to Prevent Childhood Obesity; a Qualitative Study

BACKGROUND: This study aimed to describe the acceptability and feasibility of the “HAPPY ME”, a smartphone application (app) for guiding healthy eating habits and physical activities to prevent childhood obesity, through in-depth interviews of 5th and 6th grade students of an elementary school. METHODS: A total of 25 students were recruited from grades 5 and 6 of an elementary school in Gimpo. They were asked to participate in in-depth interviews about expectations regarding the “HAPPY ME”, smartphone usage behaviors, perceptions and attitudes towards health, and satisfaction with the “HAPPY ME”, before and after the 4-week trial of the “HAPPY ME”. RESULTS: Study participants reported a high level of satisfaction regarding gamification elements such as awarding points as rewards for completing missions and using closed social networking services with friends. They also reported that their eating habits had improved after the 4-week trial. However, some students felt that the app was complicated to use and recommended that it should have prompts as notifications. CONCLUSIONS: This study showed that the “HAPPY ME” is acceptable and feasible for use with children. However, the app needs to be modified based on the results of this study.

Diagnosis of Severe Obesity in Korean Children and Adolescents

BACKGROUND: Although the obesity prevalence in Korean children and adolescents has stabilized since early 2000s, it is noted that severe obesity is increasing. However, no diagnostic criteria to define severe obesity in Korean children and adolescents has not been recommended yet. METHODS: We established two kinds of diagnostic criteria of severe obesity with the 2007 Korean National Growth Charts; 1) body mass index (BMI) criteria 1: BMI≥120% of 95th percentile or 30 kg/m², whichever is lower, 2) BMI criteria 2: ≥99th percentile. We examined the prevalence of severe obesity among children and adolescents who participated in the Fifth Korea National Health and Nutrition Examination Survey, 2010-2012 based on BMI criteria 1 and 2 as well as percentage-weight-for-height (PWH). RESULTS: We presented the age- and sex-specific BMI cut-offs of BMI criteria 1 and 2. The prevalence of severe obesity was 1.6% and 1.7% based on BMI criteria 1 and 2, respectively. The prevalence of severe obesity based on PWH was 0.8%, which was lower than the prevalences based on BMI criteria 1 and 2. CONCLUSIONS: Our diagnostic criteria of severe obesity can be utilized in the epidemiological surveys and researches before the recommendation of the formal diagnostic criteria.

Color evaluation of low viscosity bulk-fill resin with composite resin capping layer

PURPOSE: The purpose of this study was to measure the color of low viscosity bulk-fill resin with a capping layer and to compare it with the color of microhybrid composite resin. MATERIALS AND METHODS: A low viscosity bulk-fill resin (SDR) and microhybrid composite resin of shade A2 (A2) or A3 (A3) were fabricated to 4 mm thickness and light cured for 20 seconds. CIE L*a*b* values of the resin specimens were measured with a colorimeter. Then shade A2 and A3 microhybrid composite resin was capped over low viscosity bulk-fill resins in 2 mm thickness (SA2, SA3). The resin specimens were light cured for 20 seconds and the color was measured and analyzed (n = 10). Color differences (DeltaE) between SA2 and A2, SA3 and A3 were also calculated. RESULTS: L* value was highest in SDR followed by SA2 and SA3. L* value of A2 and A3 was the lowest. a* value was lowest in SDR followed by SA2 and SA3, and A2 and A3 was the highest. b* value was lowest in SDR followed by A2 and SA2, and A3 and SA3 was the highest. DeltaE between A2 and SA2 (DeltaE = 3.4), and that between A3 and SA3 (DeltaE = 3.1) was lower than the perceptible color difference threshold of DeltaE = 3.7. CONCLUSION: DeltaE between low viscosity bulk-fill resin with a capping layer and microhybrid resin was lower than the perceptible color difference threshold.