Browsing by Author "Platt, Jeffrey A."
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Item Age effect on presence, susceptibility and treatment of erosive tooth wear(2018) Algarni, Amnah Abdullah; Hara, Anderson T.; Lippert, Frank; Platt, Jeffrey A.; González-Cabezas, Carlos; Ungar, PeterErosive tooth wear (ETW) is a growing dental condition often associated with aging. This in-vitro project comprised three studies aiming to investigate the impact of tooth age on ETW susceptibility and prevention. In the first study, un-identified extracted premolars were collected and had their ages estimated using validated dental forensic methods. The premolars were examined to investigate the relationship between age and presence and severity of ETW, as well as other main dental-hard tissues conditions. ETW, dental caries, fluorosis, extrinsic staining and tooth color were evaluated using established clinical indices. In the second study, the tooth age impact on ETW susceptibility and response to preventive treatments (Sn+F, NaF, and de-ionized water control) were evaluated using representative samples from the initial study. Enamel and dentin specimens were prepared and subjected to daily erosion-treatmentremineralization cycling procedure. Surface loss (SL) was determined during and after the cycling, by optical profilometry. Similar protocol was adopted in the third study with the addition of toothbrushing abrasion to the model, in order to explore the interplay between age and toothpaste abrasivity on erosion-abrasion development. SL was measured during and after the erosion-toothbrushing-remineralization cycling. The relationships between age and the investigated variables were assessed using linear regression models. In conclusion: 1. The presence and severity of ETW, dental caries, and extrinsic staining increased with age, while of enamel fluorosis decreased. Tooth also showed to be darker with age. 2. Susceptibility of enamel and dentin to demineralization increased with age. Sn+F showed the highest anti-erosive efficacy, and was not affected by age. NaF showed lower efficacy on dentin, which increased with age. 3. Enamel and dentin SL increased with toothpaste abrasivity level. Dentin SL also increased with age. Age effect on enamel SL was observed only with low abrasive toothpaste. Age-related changes on enamel and dentin affected ETW development.Item Alternative Direct Restorative Materials for Dental Amalgam: A Concise Review Based on an FDI Policy Statement(Elsevier, 2024) Schmalz, Gottfried; Schwendicke, Falk; Hickel, Reinhard; Platt, Jeffrey A.; Biomedical and Applied Sciences, School of DentistryDental restorative procedures remain a cornerstone of dental practice, and for many decades, dental amalgam was the most frequently employed material. However, its use is declining, mainly driven by its poor aesthetics and by the development of tooth-coloured adhesive materials. Furthermore, the Minamata Convention agreed on a phase-down on the use of dental amalgam. This concise review is based on a FDI Policy Statement which provides guidance on the selection of direct restorative materials as alternatives to amalgam. The Policy Statement was informed by current literature, identified mainly from PubMed and the internet. Ultimately, dental, oral, and patient factors should be considered when choosing the best material for each individual case. Dental factors include the dentition, tooth type, and cavity class and extension; oral aspects comprise caries risk profiles and related risk factors; and patient-related aspects include systemic risks/medical conditions such as allergies towards certain materials as well as compliance. Special protective measures (eg, a no-touch technique, blue light protection) are required when handling resin-based materials, and copious water spray is recommended when adjusting or removing restorative materials. Cost and reimbursement policies may need to be considered when amalgam alternatives are used, and the material recommendation requires the informed consent of the patient. There is no single material which can replace amalgam in all applications; different materials are needed for different situations. The policy statement recommends using a patient-centred rather than purely a material-centred approach. Further research is needed to improve overall material properties, the clinical performance, the impact on the environment, and cost-effectiveness of all alternative materials.Item Antibacterial Activities of Cannabidiol Against Two Major Oral Pathogens(2024-05) Azabi, Asma A.; Windsor, L. Jack; Gregory, Richard L.; Platt, Jeffrey A.; Duarte, Simone; Goodpaster, JohnDespite advances in oral health research, biofilm-mediated oral diseases continue to pose a health challenge. Preventive measures against biofilm-mediated disease aim to inhibit pathogenic biofilm formation on tooth surfaces. Cannabidiol (CBD), a Cannabis sativa L. L. extract, has shown antibacterial properties against various bacterial species, especially gram-positive cocci. This dissertation aimed to evaluate the antibacterial efficacy of CBD against Streptococcus mutans and Porphyromonas gingivalis bacterial growth and virulence factors. The effects of CBD on the planktonic, biofilm, and total growth of S. mutans with or without nicotine and P. gingivalis, were evaluated. The minimal inhibitory concentration (MIC), minimal biofilm inhibitory concentrations (MBIC), and minimal bactericidal concentrations (MBC) of CBD were assessed. CBD concentrations ≥ 2.5 μg/ml exhibited significant inhibition (p<0.001) against S. mutans biofilm growth, as well as, biofilm metabolic activity, lactate dehydrogenase (LDH) activity, and extracellular polysaccharides (EPS) production. In the presence of nicotine, which upregulates biofilm formation, CBD demonstrated the same inhibitory effects on S. mutans growth and activities. CBD concentrations ≥ 0.47 μg/ml exhibited significant inhibition (p<0.003) against P. gingivalis biofilm growth. CBD reduced the hemagglutination activities of P. gingivalis and reduced the overall proteolytic activity. Concentrations of CBD ≥ 0.63 μg/ml provided an inhibitory effect on lysine-specific gingipain. The results of these studies demonstrate that CBD has antibacterial activities against S. mutans and P. gingivalis growth and virulence factors related to caries and periodontal diseases, respectively.Item Beam profile characterization of light-emitting-diode curing units and its effect on polymerization of a resin-matrix composite(2017) AlZain, Afnan Omar; Platt, Jeffrey A.; Chu, Tien-Min G.; Bottino, Marco C.; Hara, Anderson T.; Goodpaster, John V.; Roulet, Jean-FrancoisThe general aim of this study was to investigate the influence of the localized irradiance beam profiles from multiple light-emitting-diode (LED) light-curing units (LCUs) on the polymerization pattern within a resin-matrix composite (RMC). Irradiance beam profiles were generated from one quartz-tungsten-halogen and various single and multiple emission peak LED LCUs using a camera-based beam profiler system combined with LCU power measurements obtained using an integrating sphere/spectrometer assembly. The influence of distance on irradiance, radiant exposure (RE) and degree of conversion (DC) on the top and bottom surfaces of a RMC increment, using various LCUs, at two clinically relevant distances was investigated. Molar absorptivity of the photoinitiators present in the nano-hybrid RMC (Tetric EvoCeram bleaching shade-XL) assessed was using UV-spectrophotometry. The correlation among irradiance, RE and DC was explored. A mapping approach was used to investigate DC, microhardness and cross-link density (CLD) within 5×5×2 mm specimens at various depths; top, 0.5, 0.7, 0.9, 1.1, 1.3,1.5 mm and bottom. The localized irradiance correlation with its corresponding DC, microhardness and CLD was explored, and localized DC correlation with microhardness was assessed. The DC was measured using micro-Raman spectroscopy, and CLD was assessed by an ethanol-softening method (%KHN reduction) using an automated microhardness tester. Molar absorptivity of diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide was 20-fold higher than camphorquinone. Non-uniform LCU beam profiles caused localized polymerization discrepancies that were significant at specific depths and points within the specimens with respect to DC, microhardness and CLD, which did not follow a specific pattern regardless of the LCU or curing distance assessed. A moderate correlation was displayed among irradiance, RE and DC. The localized irradiance from the LCUs was weakly correlated with the corresponding DC, microhardness and CLD on the top surface of a RMC at both curing distances. The localized microhardness was moderately correlated with DC. In conclusion, polymerization within the RMC investigated was non-uniform and did not reflect the LCU irradiance pattern at the area assessed. Also, a mapping approach within the specimens provided a detailed polymerization pattern assessment occurring within a RMC increment. Therefore, the LCUs explored may potentially increase the risk of RMC fracture.Item A Bi-Mix Antibacterial Drug-Delivery System for Regenerative Endodontics(Office of the Vice Chancellor for Research, 2013-04-05) Palasuk, Jadesada; Hippenmeyer, Lauren; Gregory, Richard L.; Platt, Jeffrey A.; Spolnik, Kenneth J.; Bottino, Marco C.Traumatic injuries to immature teeth have traditionally been managed via apexification therapy with intracanal calcium hydroxide/Ca(OH)2. Recently, the use of a bi-mix (metronidazole-MET and ciprofloxacin-CIP) paste appears to provide more predictable results. The objective of this study was to fabricate/characterize polydioxanone (PDSII®)-based electrospun bi-mix drug-delivery systems incorporated with the combination of MET and CIP. The antibacterial property of the released media was tested against Enterococcus faecalis (Ef), Porphyromonas gingivalis (Pg) , Aggregatibacter actinomycetemcomitans (Aa). PDSII® was dissolved in HFP to obtain a 10wt.% solution. Either MET, CIP or distinct drug combinations were added into the solution followed by homogenization overnight. Six groups of study were employed: Control-100%PDS, G1-100%MET, G2-75%MET+25%CIP, G3- 50%MET+50%CIP, G4-25%MET+75%CIP and G5-100%CIP. Electrospinning was done based on optimized parameters to fabricate the distinct samples. Uniaxial microtensile testing (n=10), Fourier transform infrared spectroscopy/FTIR, scanning electron microscopy (SEM), and agar diffusion assay were used to characterize mechanical, chemical and antibacterial properties. One-way ANOVA (only for fiber diameter), Kruskal-Wallis and Mann-Whitney tests were performed (α=0.05). The results showed that uniaxial tensile strength was not significantly decreased compared to the control except G3. Average fiber diameters were in the nano-scaled range and significantly lower then the control. SEM imaging indicated a submicron fibrous morphology. FTIR confirmed the characteristic peaks for PDS as well as for the employed drugs. Agar diffusion assay suggested that the higher the CIP concentration the greater the antibacterial property against Ef, Pg and Aa. The results indicated that higher amount of CIP (G4 & G5) did not compromise mechanical properties of nanofibers and showed the highest bacterial inhibition against Ef, Pg and Aa. Optimization of the physical-mechanical properties, kinetics of drug release, and the effect of released drugs on dental pulp stem cells are currently being pursued. Partially funded by American Association of Endodontists/AAE (M.C.B.).Item Bimix antimicrobial scaffolds for regenerative endodontics(Elsevier, 2014-11) Palasuk, Jadesada; Kamocki, Krzysztof; Hippenmeyer, Lauren; Platt, Jeffrey A.; Spolnik, Kenneth J.; Gregory, Richard L.; Bottino, Marco C.; Department of Restorative Dentistry, IU School of DentistryINTRODUCTION: Eliminating and/or inhibiting bacterial growth within the root canal system has been shown to play a key role in the regenerative outcome. The aim of this study was to synthesize and determine in vitro both the antimicrobial effectiveness and cytocompatibility of bimix antibiotic-containing polydioxanone-based polymer scaffolds. METHODS: Antibiotic-containing (metronidazole [MET] and ciprofloxacin [CIP]) polymer solutions (distinct antibiotic weight ratios) were spun into fibers as a potential mimic to the double antibiotic paste (DAP, a MET/CIP mixture). Fiber morphology, chemical characteristics, and tensile strength were evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy, and tensile testing, respectively. Antimicrobial efficacy was tested over time (aliquot collection) against Enterococcus faecalis (Ef), Porphyromonas gingivalis (Pg), and Fusobacterium nucleatum (Fn). Similarly, cytotoxicity was evaluated in human dental pulp stem cells. Data were statistically analyzed (P < .05). RESULTS: Scanning electron microscopy and Fourier transform infrared spectroscopy confirmed that electrospinning was able to produce antibiotic-containing fibers with a diameter mostly in the nanoscale. The tensile strength of 1:1MET/CIP scaffolds was significantly (P < .05) higher than pure polydioxanone (control). Meanwhile, all other groups presented similar strength as the control. Aliquots obtained from antibiotic-containing scaffolds inhibited the growth of Ef, Pg, and Fn, except pure MET, which did not show an inhibitory action toward Pg or Fn. Antibiotic-containing aliquots promoted slight human dental pulp stem cell viability reduction, but none of them were considered to be cytotoxic. CONCLUSIONS: Our data suggest that the incorporation of multiple antibiotics within a nanofibrous scaffold holds great potential toward the development of a drug delivery system for regenerative endodontics.Item Bioactivity of Dental Restorative Materials: FDI Policy Statement(Elsevier, 2023) Schmalz, Gottfried; Hickel, Reinhard; Price, Richard Bengt; Platt, Jeffrey A.; Biomedical Sciences and Comprehensive Care, School of DentistryThe term bioactivity is being increasingly used in medicine and dentistry. Due to its positive connotation, it is frequently utilised for advertising dental restorative materials. However, there is confusion about what the term means, and concerns have been raised about its potential overuse. Therefore, FDI decided to publish a Policy Statement about the bioactivity of dental restorative materials to clarify the term and provide some caveats for its use in advertising. Background information for this Policy Statement was taken from the current literature, mainly from the PubMed database and the internet. Bioactive restorative materials should have beneficial/desired effects. These effects should be local, intended, and nontoxic and should not interfere with a material's principal purpose, namely dental tissue replacement. Three mechanisms for the bioactivity of such materials have been identified: purely biological, mixed biological/chemical, or strictly chemical. Therefore, when the term bioactivity is used in an advertisement or in a description of a dental restorative material, scientific evidence (in vitro or in situ, and preferably in clinical studies) should be provided describing the mechanism of action, the duration of the effect (especially for materials releasing antibacterial substances), and the lack of significant adverse biological side effects (including the development and spread of antimicrobial resistance). Finally, it should be documented that the prime purpose, for instance, to be used to rebuild the form and function of lost tooth substance or lost teeth, is not impaired, as demonstrated by data from in vitro and clinical studies. The use of the term bioactive dental restorative material in material advertisement/information should be restricted to materials that fulfil all the requirements as described in the FDI Policy Statement.Item Bond strength evaluation of two resin cements with two adhesives and analysis of mode of failure(2009) Mohan, Preethi; Platt, Jeffrey A.; Chu, Tien-Min Gabriel; Moore, B. Keith; Taskonak, Burak; Matis, Bruce A.; Cochran, Michael A.Cementing of indirect restorations with resin cements generally requires the pre-treatment of dentin with an adhesive. When dual-cured or chemical-cured resin cements are used with these single-step adhesives, incompatibility issues exist. This has resulted in manufacturers making chemical changes in their products. Kerr Dental markets a new resin cement, Nexus Third generation (NX3), which utilizes a proprietary redox system different from the second generation of composite luting agent (NX2). The aim of this study was to evaluate microtensile bond strength and mode of failure of NX3 and NX2 with two different adhesive systems (total-etch and self-etch) after 1 week and after 3 months of storage. Methods: Sixty-four non-carious teeth were sectioned to expose the dentin using a low-speed saw. Dentin surfaces were ground with 320-grit SiC paper. The adhesives Optibond Solo Plus (SOL), and Optibond All In One (AIO) were applied, and resin cements (NX2, NX3) were used to lute 4-mm composite discs to the treated dentin surfaces. Microtensile bond strength was determined at 1 week (IM) and after 3 months (3MON) of storage using a universal testing machine (MTS). All specimens were examined under the stereomicroscope to determine the mode of failure. Random specimens from each failure group were examined using scanning electron microscopy. Statistical Analysis: Comparisons between the treatment combinations for differences in microtensile bond strength were performed using Weibull-distribution survival analysis. Comparisons between the treatment combinations for differences in the failure mode were performed using Fisher’s Exact tests. The group NX3 SOL IM (30.5 MPa) had significantly higher bond strength than NX3 SOL 3MON (13.4 MPa); NX3 AIO IM (11.3MPa); NX3 AIO 3MON (8.2 MPa; NX2 AIO 3MON (5.8 MPa); NX2 SOL IM (6.3 MPa), and NX2 SOL 3MON (3.2 MPa). The group NX2 AIO IM (19.3 MPa) was not significantly different from NX3 SOL IM. The group NX2 SOL 3MON and group NX2 SOL IM had a significantly higher percentage of teeth with mixed failure than all of the other groups. None of the other groups had significantly different failure mode. The group NX3 SOL IM had 90-percent beam survival beyond 17 MPa, and NX2 AIO IM had 50 percent of beams surviving beyond 17 MPa, a better performance. For all the other groups, more than 50 percent of beams failed below 17 MPa. Results show high evidence of degradation for all groups considered in this investigation. The use of these types of cement adhesive combinations in clinical situations should be used with this understanding.Item Characterizing Curing Efficiency of EGCG-Encapsulated Halloysite Nanotube Modified Adhesives for Durable Dentin–Resin Interfaces(MDPI, 2024-12-24) Alhijji, Saleh; Platt, Jeffrey A.; Al-Maflehi, Nassr; Alhotan, Abdulaziz; Haider, Julfikar; Bottino, Marco C.; Windsor, L. Jack; Biomedical and Applied Sciences, School of DentistryMatrix metalloproteinase (MMP)-induced collagen degradation at the resin-dentin interface remains a significant challenge for maintaining the longevity of dental restorations. This study investigated the effects of epigallocatechin-3-gallate (EGCG), a potent MMP inhibitor, on dental adhesive curing efficiency when encapsulated in halloysite nanotubes (HNTs). EGCG-loaded HNTs were incorporated into a commercial dental adhesive (Adper Scotchbond Multi-Purpose) at 7.5% and 15% w/v concentrations. To isolate the effects of each component, the study included three control groups: unmodified adhesive (negative control), adhesive containing only HNTs, and adhesive containing only EGCG (0.16% and 0.32%, equivalent to the EGCG content in EGCG-HNT groups). Degree of conversion (DC), polymerization conversion (PC), and Vickers micro-hardness (VHN) were assessed to evaluate curing efficiency. The addition of 7.5% EGCG-encapsulated HNTs maintained curing properties similar to the control, showing no significant differences in DC (80.97% vs. 81.15%), PC (86.59% vs. 85.81%), and VHN (23.55 vs. 24.12) (p > 0.05). In contrast, direct incorporation of EGCG at 0.32% significantly decreased DC (73.59%), PC (80.63%), and VHN (20.56) values compared to both control and EGCG-HNT groups (p < 0.05). Notably, HNT encapsulation mitigated these negative effects on polymerization, even at higher EGCG concentrations. These findings demonstrate that EGCG encapsulation in HNTs can maintain the curing efficiency of dental adhesives while potentially preserving the MMP-inhibitory benefits of EGCG.Item Clinical Evaluation of a Universal Adhesive in Non-Carious Cervical Lesions(2016) Rouse, Matthew A.; Platt, Jeffrey A.; Jackson, Richard D.; Carlson, Timothy J.; Matis, Bruce A.; Cook, Norman BlaineThe “total-etch” or “etch-and-rinse” systems have been the gold standard of dental bonding for decades. However, these systems are very technique-sensitive and time-consuming compared to newer “self-etch” or “self-adhesive” systems and have been implicated in cases of postoperative sensitivity. The purpose of this study was to compare the effects of two surface treatment protocols (self-etch vs. selective-etch) on the clinical performance of a universal adhesive and resin composite in Class V non-carious cervical lesions (NCCLs). Thirty-three volunteer subjects (17 male; 16 female; age range = 20 to 75 years) having at least two NCCLs were selected from patients of record at Indiana University School of Dentistry. Each subject received one resin composite restoration (Tetric EvoCeram, Ivoclar Vivadent) utilizing a self-etch (SfE) universal adhesive (Adhese Universal, Ivoclar Vivadent) with no separate enamel etching and another restoration utilizing adhesive and selective enamel etching (SelE) with 37% phosphoric acid (H3PO4). Both the adhesive and composite were placed following the manufacturer’s instructions. The two techniques were compared for differences in sensitivity, retention, marginal discoloration, marginal adaptation, and clinical acceptability at baseline and 6 months using the Cochran-Mantel-Haenszel tests for stratified, ordered categorical outcomes. Seventy-four restorations (37 SfE, 37 SelE) in 30 volunteers were evaluated at 12 months. No significant differences were found between the SfE and SelE groups for any variable at the 12-month recall (p>0.21). Retention was 100% at 12 months for both groups. Marginal adaptation was significantly worse at 12 months than at baseline for SelE (p=0.0163), but there was no difference for SfE (p=0.08). Sensitivity improved significantly from baseline to 12 months for both SelE (p=0.0113) and SfE (p=0.0128). The results obtained from this study are comparable to results observed in similar studies. Like similar studies involving self-etch adhesives in non-carious cervical lesions, our study showed no restorations lost to caries and excellent retention. The deterioration of selective-etch dentin margins was a result that differed from similar studies. A likely explanation for this finding would be the difficulty of controlling precise placement of phosphoric acid gel, causing undesired etching of dentin; this could result in suboptimal bonding to dentin. This report on 12-month data for a two-year study indicates significantly reduced sensitivity for both the SelE and SfE groups, and deterioration of SelE marginal adaptation. No decreases in retention, marginal discoloration, or clinical acceptability were observed in either group.