Browsing by Author "Platt, Jeffrey"
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Item THE EFFECT OF NANO-FILLED RESIN COATING ON FLUORIDE RELEASE IN A NEW CONVENTIONAL GLASS IONOMER CEMENT(Office of the Vice Chancellor for Research, 2012-04-13) Al Dehailan, Laila; Eckert, George; Platt, JeffreyThe objective of this study was to evaluate fluoride release amounts and patterns from high strength tooth filling material (EQUIA™) which is a con-ventional Glass Ionomer Cement, and investigate whether the application of nano-filled resin-based coating with different thicknesses has any effect on fluoride release from this new material. A total of 120 disc shaped specimens (10 x 2 mm) of EQUIA™ were fabricated according to manufacturer’s in-structions. Samples were subsequently divided into three groups: no resin coating; coated with nano-filled resin-based coat; coated with nano-filled resin-based coat then subjected to abrasion using a mechanical tooth brush-ing machine. Each specimen was soaked individually into a polyethylene container with 20 ml of distilled water and stored at 37ºC. Samples from each group were soaked for four time points; 1 day, 7 days, 14 days and 21 days. Fluoride content was then measured using a fluoride-specific ion elec-trode (Model 9609BNWP, Orion Research, Boston MA, USA). The effects of time and coating on fluoride release were analyzed using two-way analysis of variance (ANOVA), with multiple comparisons performed using the Sidak method at an overall 5% significance level. The distribution of the fluoride release measurements was examined and a natural logarithm transformation of the data was necessary to satisfy the ANOVA assumptions. The time-by-coating interaction was significant (p<0.0001). We can conclude that fluo-ride level significantly increased with time for non-coated and coated then abraded samples only. Application of resin coat significantly reduced fluoride release. Also, subjecting coated samples to tooth brush abrasion increased the fluoride release when compared to coated specimens but was still signifi-cantly less than uncoated samples.Item Effect of post-irradiation polymerization on selected mechanical properties of six direct resins(J-STAGE, 2022) Sochacki, Sabrina; Karczewski, Ashley; Platt, Jeffrey; Roberts, Howard W.; Biomedical Sciences and Comprehensive Care, School of DentistryThis study evaluated the post-irradiation mechanical property development of six resin composite-based restorative materials from the same manufacturer starting at 1 h post irradiation, followed by 24 h, 1 week, and 1 month after fabrication. Samples were stored in 0.2M phosphate buffered saline until testing. Flexural strength, flexural modulus, flexural toughness, modulus of resiliency, fracture toughness, and surface microhardness were performed at each time interval. Mean data was analyzed by Kruskal Wallis and Dunn's post hoc testing at a 95% level of confidence (α=0.05). Results were material specific but overall, all resin composite material mechanical properties were found to be immature at 1 h after polymerization as compared to that observed at 24 h. It may be prudent that clinicians advise patients, especially those receiving complex posterior composite restorations, to guard against overly stressing these restorations during the first 24 h.Item Evaluation of contact angle between root canal sealers and dentin treated with calcium hydroxide and irrigation solutions(2018) Nakaparksin, Pranai; Platt, Jeffrey; Levon , John A.; Bringas, Josef S.; Brown, David T.Background: Numerous studies have reported the effect of long-term use of calcium hydroxide Ca(OH)2 to dentin. Nevertheless, there is little information available about the effect of Ca(OH)2 on wettability to the dentin. Objective: To investigate the effect of Ca(OH)2 application on dentin for two and four weeks on the wettability of two root canal sealers. Methods: Polished caries-free human dentin discs (n = 156) were allocated into 12 groups; G1 and G3 had two weeks’ treatment, G4 and G6, four weeks treatment. G1 and 101 G4 were treated with sterile water. G2, G3, G5 and G6 were treated with Ca(OH)2. G1, G3, G4, and G6 were irrigated with 6.0-percent NaOCl and 17-percent EDTA while G2, and G5 were irrigated with sterile water. Then, contact angles between Tubli-Seal and the treated dentin surfaces were measured. G7 and G12 were treated in the same fashion but were treated with BC sealer. Surface morphology evaluation of G1 and G6 was carried out by scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX). Statistics were performed using three-way ANOVA and pair-wise comparisons between groups (α = 0.05). Results: Tubli-Seal (G1 through G6) had significantly smaller values for contact angles than BC sealer (G7 through G12) (p < 0.05). For the Tubli-Seal groups (G1 through G6), G4 had the highest mean of contact angles at 104.9 ± 1.9°, whereas G5 presented the lowest mean of contact angles at 85.4 ± 15.1. For the BC sealer groups (G7 through G12), G10 had the highest mean of contact angles at 145.4 ± 1.3°, while G11 demonstrated the lowest mean of contact angles at 130.2 ± 2.6°. Groups with Ca(OH)2 treatment with water irrigation (G2, 5, 11) had significantly lower contact angle than groups with Ca(OH)2 with chemical irrigation (G3, 6, 12) (p < 0.05), except G8, 9. According to SEM and EDX, water irrigation solution showed higher remaining Ca(OH)2 than irrigation with the chemical solution while Ca(OH)2 with chemical irrigation 102 demonstrated no Ca(OH)2 remaining after irrigation, similar to the surface of the control group. Conclusion: Within the limitations of this study, Tubli-seal has better wettability on dentin than BC sealer. Remaining calcium hydroxide demonstrated a trend toward decreased contact angle between dentin and root canal sealers. Moreover, two-minute irrigation with 6-percent NaOCl and 17-percent EDTA can remove calcium hydroxide from polished dentin surfaces.Item EVALUATION OF MICROTENSILE BOND STRENGTH AND MICROLEAKAGE OF A ONE-STEP SELF-ETCH ADHESIVE(Office of the Vice Chancellor for Research, 2012-04-13) AlZain, Afnan; Eckert, George; Platt, JeffreyNew dental glue (G-aenial Bond-GB) was developed to increase the strength of bonding the white tooth filling to the tooth. An extra roughening step of the tooth surface using a specific acid should help the flow of the glue to the tooth and increases the strength of the bond between the tooth and the filling. Therefore, this study was done to evaluate how strong the bond is between the filling and the tooth using GB, and how much GB leaks and compare both tests with two other glue products and, with and without adding an extra roughening step. For the bond strength test, human molars teeth were divided into 5 groups, each containing 15 teeth. In 3 groups, each glue type was applied on tooth dentin according to company's instructions. In the last 2 groups an extra roughening step using a specific acid was added before applying the glue. The samples were stored in fake saliva where four samples were soaked for 48h and four samples were placed in a machine (thermocycling) that resembles drinking hot and cold beverages where samples are exposed to hot and cold water for 40 days and then the strength of the bond was tested (α=0.05). The broken edges were examined using a light microscope. For the leak test, human molars were divided randomly into the same 5 groups as bond strength test but each containing 11 teeth. A cavity was pre-pared and filled on the check and tongue sides of the tooth. Teeth were then also subjected to thermocylcling and stored for four weeks, soaked in dye for 24 hours and sectioned. The dye penetration was evaluated using light mi-croscopy (α=0.05). Bond strength of GB was significantly higher when an acid roughening step was added. No significant difference in leak of GB was observed.Item Optimizing light-cured composite through variations in camphorquinone and butylhydroxytoluene concentrations(2016-05) Nassar, Hani; Chu, Tien-Min; Platt, Jeffrey; Biomedical and Applied Sciences, School of DentistryThe use of a free-radical polymerization inhibitor, butylhydroxytoluene (BHT), and a common photo-initiator, camphorquinone (CQ), to reduce polymerization stress in dental composite was investigated in this study. Samples were prepared by mixing Bis-GMA, UDMA, and TEGDMA at a 1:1:1 ratio (wt%), and silanized borosilicate glass fillers at 70 wt% were added to form the composite. Sixteen groups of resin composite were prepared using combinations of four CQ (0.1%, 0.5%, 1.0%, and 1.5%) and four BHT (0.0%, 0.5%, 1.0%, and 1.5%) concentrations. For each group, six properties were tested, including flexural strength (FS), flexural modulus (FM), degree of conversion (DC), contraction stress (CS), stress rate, and gel point (GP). The effects of CQ and BHT combinations on each of these properties were evaluated using two-way analysis of variance (ANOVA) and Fisher’s Protected Least Significant Differences test at the 5% significance level. Groups with low CQ and BHT showed moderate values for FS, FM, and CS with a 70% DC. Increasing the BHT concentration caused a decrease in CS and DC with an increase in GP values. Increasing the CQ content led to a steady increase in values for FS and FM. High CQ and BHT combinations showed the most promising values for mechanical properties with low stress values.Item Physicomechanical properties of a zinc-reinforced glass ionomer restorative material(2014) Al-Angari, Sarah S.; Hara, Anderson T.; Chu, Tien-Min; Platt, Jeffrey; Eckert, George; Cook, N. Blaine; Department of Restorative Dentistry, School of DentistryWe compared a zinc-reinforced glass ionomer restorative material (ChemFil Rock) with three commercially available glass ionomer cements (GICs), namely, Fuji IX GP Extra, Ketac Molar Quick Aplicap, and EQUIA Fil, with respect to fracture toughness, microhardness, roughness, and abrasive wear. Fracture toughness (KIC) was tested according to ISO 13586 (n = 10). Hardness, roughness, and abrasive wear were also tested (n = 9). Data were analyzed using the Wilcoxon rank-sum test with adjustment for multiple comparisons (α = 0.05). As compared with the other GICs ChemFil Rock exhibited a greater increase in surface roughness (P < 0.05) and lower microhardness (P < 0.01). The wear resistance of ChemFil Rock was comparable to that of the other GICs (P > 0.05). ChemFil Rock had significantly lower fracture toughness as compared with EQUIA Fil (P = 0.01) and significantly higher fracture toughness as compared with the other GICs (P < 0.02). In conclusion, as compared with the three other commercially available GICs, ChemFil Rock had intermediate fracture toughness, the lowest microhardness, and the greatest change in surface roughness.Item Stainless Steel Crown Success Using the Hall Technique: A Retrospective Study(Elsevier, 2014-12) Ludwig, Kevin; Fontana, Margherita; Vinson, LaQuia; Platt, Jeffrey; Dean, Jeffrey; Department of Pediatric Dentistry, IU School of DentistryBackground In this retrospective study, the authors evaluated the clinical and radiographic success of stainless steel crowns (SSCs) used to restore primary molars with caries lesions, placed by means of both the traditional technique (involving complete caries removal and tooth reduction before placement of the SSC) and the Hall technique (involving no caries removal, no crown preparation and no use of local anesthetic before placement of the SSC). Methods The authors conducted a retrospective chart review by using the patient records at a private pediatric dental practice at which the Hall technique had been introduced in June 2010 as an alternative treatment to traditional SSC placement. The inclusion criteria were caries lesions on a primary molar with no clinical or radiographic evidence of pulpitis, necrosis or abscess, as well as follow-up of at least six months or until failure, whichever came first. They graded restoration success by using a four-point scale based on presence or loss of the SSC, and whether or not the patient needed further treatment associated with pulpal pathology or secondary caries. They collected and summarized patient demographic information. They used a Kaplan-Meier survival curve along with 95 percent confidence intervals to evaluate clinical success. Results The authors found that 65 (97 percent) of 67 SSCs placed with the Hall technique (mean observation time, 15 months; range, four-37 months) and 110 (94 percent) of 117 SSCs placed with the traditional technique (mean observation time, 53 months; range, four-119 months) were successful. Conclusion Findings of this study show a similar success rate for SSCs placed with the traditional technique or the Hall technique.Item Step-Stress Fatigue, Fracture Toughness and Load to Failure of an Additively Manufactured Ceramic Filled Hybrid Crown Material(2024-05) Roberts, Evan; Chu, Tien-Min G.; Platt, Jeffrey; Morton, DeanBackground: The prevailing trend in dental practice is toward fully digital workflows with additive and subtractive manufacturing. Computer Aided Design Computer Aided Manufacturing (CADCAM) and subtractive manufacturing have led to a proliferation of established restorative materials. In September 2021, the FDA approved Varseosmile Crown Plus, by Bego, for utilization as a permanent crown. This novel composite is the first additive manufactured material to receive approval as a ceramic hybrid for permanent single crowns, inlays, onlays and veneers.[1] The manufacturer categorizes Varseosmile Crown Plus as a ceramic filled hybrid composed of esterification products of 4.4'-isopropylidiphenol, ethoxylated and 2-methylprop-2enoic acid, silanized dental glass.[2] The total content of inorganic fillers (particle size 0.7 μm) is 30 – 50 % by mass.[2] Information published on the mechanical properties of Varseosmile Crown Plus is limited due to its novelty. Hypotheses: There will be no difference in step-stress fatigue on disc specimens, no difference in fracture toughness on bar shaped specimens and no difference in load to failure on tooth shaped specimens between Varseosmile Crown Plus and Vita Enamic. Methods: Two materials were assessed in three tests. Six bars of both materials were utilized to assess fracture toughness following the ISO6872:2015[3] standard. The fracture toughness was assessed utilizing the single edge v-notch beam (SEVNB) in a three-point bending test. Ten samples of each material were used to evaluate the fatigue resistance utilizing the stepwise stress method on disc samples according to ISO6872:2015[3] with a piston-on-three-ball configuration at room temperature under dry conditions. The final material property assessment was load-to-fracture in crown shaped samples adhesively bonded to dentin analogs. A mandibular right first molar (#30) was prepared on a typodont. The preparation was scanned and digitized to make twenty two dentin analogs (NEMA grade G10). A restoration was designed, and eleven crowns were printed or milled from each material. Restorations were bonded to the G10 analog with self-adhesive resin cement. Each crown was axially loaded utilizing a universal testing machine until failure. Results were recorded and compared between groups using two-sample t-tests and Weibull survival analysis. Results: Step-stress fatigue testing revealed Vita Enamic had an average maximum tensile stress of 143.3 12.7 MPa and Varseosmile Crown Plus demonstrated an average maximum tensile stress of 107.5 21.8 MPa. The differences in fatigue failure load (p<0.001), number of loading cycles survived (p<0.001), number of steps survived (p=0.006) and average maximum tensile stress (p<0.001) were all statistically significant between the two materials tested. The fracture toughness testing resulted in an average fracture toughness of 1.343 ± 0.067 MPam for Enamic and 0.878 ± 0.095 MPam for Varseosmile Crown Plus. The difference in fracture toughness between the tested materials was statistically significant (p<.001). The 95% confidence interval for the average KIC value was 1.2735 to 1.4132 MPam for the control and 0.7787 to 0.9771 MPam for the experimental material. The average flexural strength for Varseosmile Crown Plus was 73.619 ± 21.76 MPa. The load to failure testing on crown shaped specimens produced an average failure load of 2342.46 ± 225.46 for Varseosmile Crown Plus and 1871.09 ± 455.07 N for Vita Enamic. Conclusion: A clinical use of Varseosmile Crown Plus should expect a reduction in service life relative to an equivalent restoration of Vita Enamic based on the significantly reduced mechanical properties of fatigue strength and fracture toughness. The load to failure on a crown shaped specimen suggests high initial resistance to compressive force vectors. An established protocol for best practice methods of mixing the composite resin before printing needs to be identified. Once established, the mechanical properties should be re-evaluated, and clinical studies conducted to evaluate for real-world clinical outcomes.Item The use of traditional and novel techniques to determine the hardness and indentation properties of immature radicular dentin treated with antibiotic medicaments followed by ethylenediaminetetraacetic acid(Wolters Kluwer, 2014-10) Yassen, Ghaeth H.; Al‑Angari, Sarah S.; Platt, Jeffrey; Department of Restorative Dentistry, School of DentistryOBJECTIVE: The objective was to investigate the effect of intracanal antibiotic medicaments followed by ethylenediaminetetraacetic acid (EDTA) on the indentation properties and hardness of radicular dentin using a BioDent reference point indenter and a traditional microhardness technique, respectively. MATERIALS AND METHODS: Specimens with intact root canal dentin surfaces and polished radicular dentin specimens were obtained from immature human premolars. Each type of specimen was randomly assigned (n = 10 per group) and treated with either double antibiotic paste (DAP) for 4-week followed by EDTA for 5 min, triple antibiotic paste (TAP) for 4-week followed by EDTA for 5 min, EDTA for 5 min or Hank's balanced salt solution (control). The BioDent reference point indentor and Vickers microhardness tester were used to measure the indentation properties of root canal surfaces and the hardness of polished dentin specimens, respectively. One-way ANOVA followed by Fisher's protected least significant differences were used for statistical analyses. RESULTS: Both types of radicular dentin treated with antibiotic pastes and/or EDTA had a significant increase in the majority of indentation properties and a significant reduction in hardness compared to the untreated dentin. Furthermore, treatment of dentin with antibiotic pastes and EDTA caused significant increases in indentation properties and a significant reduction in hardness compared to EDTA-treated dentin. However, the RPI technique was not able to significantly differentiate between DAP + EDTA and TAP + EDTA-treated dentin. CONCLUSION: Dentin treated with antibiotic medicaments followed by EDTA had a significant increase the indentation properties and significantly reduction in hardness of radicular dentin.