Browsing by Author "Soto Rojas, Armando E."
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Item Effect of nylon-6 and chitosan nanofibers on the physicomechanical and antibacterial properties of an experimental resin-based sealant(2014) Hamilton, Maria Fernanda; Bottino, Marco C.; Cook, Norman Blaine, 1954-; Hara, Anderson T.; Zandoná, Andréa G. Ferreira (Andréa Gonçalves Ferreira), 1969-; Gregory, Richard L.; Soto Rojas, Armando E.Purpose: Dental sealant forms a physical barrier to prevent pit and fissure caries; therefore, the retention rate becomes a main factor of the sealant’s effectiveness. Electrospun nylon-6/N6 nanofibers have shown good mechanical properties, such as high tensile strength and fracture toughness. Chitosan/CH has received significant attention due to properties such as antibacterial activity. The purpose of this study was to synthesize and evaluate the effect of incorporating N6 and CH electrospun nanofibers on the physical-mechanical and antibacterial properties of an experimental resin-based sealant. Methods and Materials: Nanofiber synthesis: N6 pellets were dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol at a concentration of 10wt%. Practical-grade chitosan was dissolved in trifluoroacetic acid and dichloromethane (60:40 TFA/DCM) at 7 wt%. Electrospinning parameters were optimized in order to fabricate defect-free N6 and chitosan nanofiber mats. Morphological and chemical characterizations were performed by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively after vacuum drying the mats for 48 h. The average fiber diameter was determined from SEM images by measuring the diameter of 120 fibers using ImageJ software. Experimental Sealant: N6 and CH electrospun mats (3×3cm2) were immersed into a resin mixture of BIS-GMA/TEGDMA. Once no bubbles were seen, the resin-modified N6 and CH mats were put on a glass plate, light-cured (“TRIAD 2000”) for 2 min and then submitted to a cryomilling process to obtain a fine micron-sized powder. Three different filler levels (1 wt%, 2.5 wt%, 5 wt%) were used to prepare the N6 and CH incorporated resin-based sealants. Additionally, a commercially available resin-based sealant and the experimental resin mixture (unfilled) were used as controls. Three-point flexural testing, Vickers microhardness testing, and agar diffusion testing were performed on the experimental sealants and the commercial sealant. Data were analyzed by one-way ANOVA and Fisher's Protected Least Significant Differences Pair-wise comparisons between groups (5%). Results: The average fiber diameter for N6 was found to be 503±304 nm and 595±411 nm for CH. No significant difference was found between fiber diameter (p = 0.0601). FTIR confirmed the characteristic peaks for N6 ((CO-NH and [-(CH2)5-].) and CH (N-H and C2F3O2-). CH-5% group had significantly higher (p = 0.0000) FS (115.3±4.5 MPa) than all other groups. CH-1% and CH-2.5% groups had significantly higher FS than the control (unfilled) (p = 0.0016 and p = 0.0033 respectively); Helioseal Clear (p = 0.0000), and nylon groups. N6-5% had significantly higher flexural strength than Helioseal Clear (p = 0.0013) and N6-2.5% (p = 0.0250). CH-1% had significantly higher hardness values than all other groups, and CH-5% (p = 0.0414) had significantly higher values than N6-2.5%. No antibacterial inhibition was seen in any of the tested groups. Conclusions: CH and N6 nanofibers were successfully prepared via electrospinning and used to modify the experimental resin-based dental sealants. The overall results indicated that CH-containing sealants presented the highest flexural strength and hardness; however, none of the CH groups displayed antimicrobial properties. Further investigation is needed to enhance the physico-mechanical properties of the experimental resin-based sealants using nylon-6 and CH.Item Evaluation of two methods of fissure treatment before sealant placement on different caries levels(2009) Chitre, Swati; Cochran, Michael A.; Soto Rojas, Armando E.; Chu, Tien-Min Gabriel; Fontana, Margherita Ruth, 1966-; Carlson, TimothyOcclusal pits and fissures are ideal places for caries development. Placement of dental sealants has been reported to be effective in preventing this process. However, the effectiveness of dental sealants has been reported to be influenced by clinical factors, such as preparation and placement techniques. A report recently published by the American Dental Association on the clinical recommendations for use of pit-and-fissure sealants included critical evaluation and a summary of relevant scientific evidence on the use of sealants aimed at assisting clinicians. The report addressed concerns such as: Does placing sealants over early (noncavitated) lesions prevent progression of the lesions? Are there any techniques that could improve sealants’ retention and ffectiveness in caries prevention? The investigators concluded that there is limited and conflicting evidence to support that mechanical preparation with a bur results in higher retention rates in children and recommend that pit-and-fissure sealants should be placed on early (noncavitated) carious lesions. The purpose of this in vitro study was to evaluate two methods of fissure treatment before sealant placement on different caries levels. In this study, 135 extracted human molars (ICDAS codes 0 to 2) were collected and ranked by a calibrated examiner into three groups. These were further divided into three subgroups (nine total). Occlusal surfaces were prepared with: 1) a ¼-mm round bur, 2) air abrasion, and 3) no treatment as a control. All groups were etched with 3.0- percent phosphoric acid for 15 seconds, rinsed thoroughly, and dried with an air water syringe. Opaque dental sealants were placed on the etched occlusal surfaces according to the accepted clinical standards and light-cured for 30 seconds. All groups were thermocycled for 5000 cycles. The roots of the teeth were painted with nail varnish, root apices were sealed with wax, and the occlusal surfaces were immersed in 1.0-percent methylene blue for a full 24 hours. The next day the teeth were cleaned, and the roots were sectioned to expose the crowns. Crowns were cut along the occlusal surfaces in the buccolingual direction. The sectioned surfaces were examined under the Nikon SMZ 1500 microscope for sealant penetration in the fissure and microleakage along the sealant enamel interface. The analyses were performed on a transformation of the sealant penetration percentage commonly used for calculated percentages: sin-1(p1/2). The effects of the type of group, the ICDAS code, and the fissure type on sealant penetration percentage were compared using ANOVA. The effects on microleakage and bubbles were compared using GEE methods applied to logistic regression. The effects on dye penetration were compared using GEE methods applied to cumulative logistic regression to account for the ordered categories of the dye penetration scale. In the findings of sealant penetration, the group type did not have a significant effect on sealant penetration (p = 0.195). ICDAS codes had a significant effect on sealant penetration (p = 0.0113) where ICDAS Code 0 had greater penetration than ICDAS codes 1 and 2. Fissure type had a significant effect on sealant penetration (p = 0.0001) where fissure types V and U had greater sealant penetration than Fissure types Y and W. In the findings of microleakage, the type of group had a significant effect on microleakage (p = 0.0004) where the abrasion group had increased microleakage as compared with the 1/4 round bur and control groups. ICDAS code had a significant effect on microleakage (p = 0.0022) where ICDAS code 0 had less microleakage as compared with ICDAS code 1 and 2. Fissure types V, U, Y, and W did not have a significant effect on microleakage (p = 0.721).Item Learning experience about the use of the ICDAS by dental students in the clinic(2024) Alfawaz, Ibrahim; Soto Rojas, Armando E.; Al Dehailan, Laila A.; Willis, LisaBackground: The International Caries Detection and Assessment System (ICDAS), established in 2002, is a method to detect and assess the severity of dental caries. It provides scores ranging from 0 (sound tooth) to 6 (extensive cavitation). This system enhances the accuracy of caries diagnosis and assists in conducting research related to public health. Objective: This study aims to explore the knowledge and learning experience of ICDAS in the third-year (D3) and fourth-year (D4) students at Indiana University School of Dentistry (IUSD), evaluate how well they can utilize it, and determine whether they use the ICDAS in clinics. Material and Methods: A questionnaire to assess knowledge and use of ICDAS in the clinic was developed by the student investigator and committee members. The initial questionnaire underwent pilot testing, received feedback from faculty and alums, and was evaluated by the Center for Survey Research. Institutional Review Board (IRB) was obtained. The questionnaire included open-ended and Likert scale questions to assess students' attitudes, knowledge, perceptions, and potential behavioral modifications regarding the ICDAS. The questionnaire was anonymously distributed through Qualtrics and designed to ensure all responses were obtained, specifically targeting D3 and D4 dental students. The responses were gathered and subjected to statistical analysis. Results: 75 Out of 229 dental students (32% of D3 and D4) responded to the survey. This group had 40% D3 and 60% D4 respondents. D4 students were more confident in identifying ICDAS 1 lesions (p=0.041). Students with prior experience were less likely to correctly identify an ICDAS 3 (p=0.034). Additionally, they were less likely to accurately identify an ICDAS 4 (p=0.010). 93% of students stated that ICDAS scores affected treatment. Four ICDAS scoring systems were also discussed with students. About 90% of students indicated that ICDAS caries stages helped them choose preventive or restorative treatments to enhance minimally invasive dentistry. Over 90% of students disagreed with negative statements such as difficulty understanding, learning, having too many scores, and being inadequate for the clinical setting. Conclusion: Third and fourth-year dental students in IUSD exhibit positive learning experiences in their continuing clinical practice with ICDAS and demonstrate adequate knowledge of ICDAS.Item Tap Water Filtration and Purification Usage and Their Impact on Fluoride Concentration - A Community-Based Study(2025-02) Hazzazi, Loai; Lippert, Frank; Soto Rojas, Armando E.; Martinez Mier, E. Angeles; Hara, Anderson; Maupomé, Gerardo; Nassar, Hani M.Water filtration and purification systems (WFPS) are a rapidly growing market aimed at improving water quality by removing harmful chemicals and bacteria. However, there is limited research on how WFPS affect fluoride concentrations, which are critical for preventing dental caries, as well as other essential minerals like calcium, magnesium, potassium, and sodium, which are vital for overall health. Our first aim was to assess the prevalence of WFPS use among residents of Indianapolis, Indiana, through a distributed questionnaire. Water samples were collected from participants to analyze fluoride, calcium, magnesium, potassium, and sodium. For the second aim, we replicated this study in Jeddah, Saudi Arabia, to compare findings across different geographic and cultural contexts. In the third aim, we conducted a laboratory study to test nine popular water pitcher filter brands for their effects on fluoride and other essential minerals. The results of the first aim of the study revealed that 71% of participants used some type of WFPS, with water pitcher filters being the most commonly used (31%). Additionally, reverse osmosis systems significantly reduced all studied minerals, while water softeners increased sodium concentrations. For the second aim, 60% of participants reported using WFPS, with reverse osmosis systems being the most commonly selected (62%). The findings also indicated that unfiltered tap water samples had very low fluoride levels, and reverse osmosis systems effectively reduced all tested minerals. The third aim demonstrated that water pitcher filters did not completely remove fluoride but had varying effects on the other studied minerals. In conclusion, in both locations, WFPS were widely used, but the types of systems preferred, and the mineral content of public water supplies varied. Our study also highlighted the importance of understanding the effects of different WFPS on essential minerals, especially fluoride, which plays a key role in preventing dental caries. These findings emphasize the need for further research to understand how WFPS impact both water quality and health outcomes, particularly in regions with differing water supplies and public health practices.Item The Effect Of Faucet Mount Water Filters On The Fluoride And Calcium Concentrations Of Tap Water(2023) Aljuaid, Ahmed Saeed M.; Lippert, Frank; Soto Rojas, Armando E.; Al Dehailan, LailaBackground: Fluoride and other minerals are present in drinking water in varying amounts either naturally or have been intentionally added. Minerals in water are important for the provision of electrolytes (calcium, magnesium, potassium) and for caries prevention (fluoride, calcium). However, the use of water filtration systems, which have become increasingly popular, can lead to a significant reduction in the concentration of some minerals in tap water. Objectives: to investigate the effect of faucet mount filters on fluoride and calcium concentrations in tap water. Materials and Methods: We investigated a convenience sample of 15 different brands of faucet mount water filters (PUR, Brita, Waterdrop, Culligan, Engdenton, DuPont, Instapure, iSpring, OEMIRY, IVO, SJ WAVE, WINGSOL, ZeroWater, AIBERLE, MIST) available in different home improvement retail stores in Indianapolis as well as on amazon.com. Water samples were collected prior to installation and after removal of the filters to determine fluoride and calcium baseline values. After mounting the filters, samples were collected at intervals when 1 L, 5 L, 10 L, 30 L, 50 L, 75 L, and 100 L of water passed through each filter for fluoride and calcium analysis. Fluoride analysis was conducted by using a fluoride ion-specific electrode (Orion #96-909-00). Calcium analysis was carried out by atomic absorption spectrometer. Results: There were significantly lower (p < 0.05) fluoride and calcium levels in PUR, Brita, and AIBERLE filters compared with unfiltered water, while Waterdrop, WINGSOL, and MIST had higher levels of fluoride and calcium. Overall, differences between filtered vs. unfiltered water were small for fluoride (up to 4-percent reduction) but larger for calcium (up to 25-percent reduction). Conclusion: The results suggest that faucet mount filters may not affect fluoride concentrations in tap water in a clinically significant manner, but some may reduce calcium concentrations significantly.