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Browsing by Author "Platt, Jeffrey A., 1958-"
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Item A clinical study of sealants polymerized with two different light sources(2004) White, Marcia Stoddart; Avery, David R.; Platt, Jeffrey A., 1958-; Moore, B. Keith; Weddell, James A. (James Arthur), 1949-; Sanders, Brian J.; Matis, Bruce A.This clinical study investigated the efficacy of the new LED LCU technology when compared to that of the QTH LCU by evaluating retention and wear of Clinpro (3M ESPE) sealant material over six months of function. This study was designed as a split mouth, randomized clinical study. Sealants were placed and polymerized on contralateral teeth of 35 patients, 33 of which successfully completed the study. The sealants were evaluated for clinical retention at baseline, three months, and six months by two evaluators. For the wear analysis, the area of the sealant wear at six months is reported. Nine pairs of molars and 22 pairs of premolar teeth were used. This sample size is smaller than the original sample used for clinical evaluation, because a number of the baseline impressions had to be discarded due to poor impression quality. Subsequent impressions were taken at three months, and six months. Epoxy replicas were made from the impressions and the occlusal surface of each replica was digitized using SigmaScan software. A cummulative legit model was applied to the clinical data, and a linear model was applied to the wear analysis. The results for clinical retention over the six months of function were as follows. At Baseline, for the QTH, 97.3 percent of the teeth received an Alpha score; 2.7 percent received a score of B. For the LED, 87.7 percent received a score of A; 12.3 percent received a score of B. At three months follow-up, for the QTH, 93.1 percent received a score of A; 6.9 percent received a score of B. For the LED, 86.1 percent received a score of A; 12.5 percent received a score of B, and 1.14 percent received a score of C. At six months follow-up, for QTH; 91.7 percent received a score of A; 8.3 percent received a score of B. For the LED, 83.3 percent received a score of A; 15.3 percent received a score of B, and 1.14 percent received a score of C. The hypothesis was that there would be no significant difference in clinical retention and wear of Clinpro's sealant polymerized with the QTH or the LED light sources over six months of function. Based on the results of this clinical study, the following conclusions can be made: 1) At baseline, Clinpro's sealant polymerized with QTH light source showed marginally significant better retention than LED light source (p-value 0.05001). 2) There was no significant difference between light sources for sealant clinical retention at three-month and six-month follow up visits. 3) Wear analysis resulted in marginally significant more wear for molar sealants polymerized with LED LCU (p-value 0.0755). 4) Wear analysis showed no significant difference for premolar sealants polymerized with either light source.Item Color stability of light-activated bleach shade composites(2010) Al-Yakoubi, Yaser; Levon, John A.; Platt, Jeffrey A., 1958-; Kim, Seok-jin, 1967-; Brown, David T.; Andres, Carl J., 1942-This study evaluated the color stability of bleach shade composites when activated by a high-intensity quartz tungsten-halogen (QTH) light source after 1 day, 7 days, and 30 days of exposure to different conditions. The color stability of bleach shade composites depends on various factors, namely, the resin material, the shade of the resin material, the storage method, and the storage time.Item A comparison of hardness and abrasion resistance of two sealant materials after polymerization from different distances by different light sources(2008) Ritchie, Craig D.; Dean, Jeffrey A.; Avery, David R.; Sanders, Brian J.; Weddell, James A. (James Arthur), 1949-; Platt, Jeffrey A., 1958-; Tomlin, Angela; Moore, B. KeithBACKGROUND The efficacy of sealants to aid in the prevention of pit and fissure caries is well documented. In order for the sealants to be effective, they must be placed properly and retained for as long as possible. Clinicians must be aware that the proper placement of sealants is technique-sensitive and must be well controlled in order to achieve the best results. This study aims to determine if certain variables have an effect on curing of the sealant material to a degree that would compromise its integrity, strength, and longevity. METHODS AND MATERIALS Two commonly used sealant materials Ultraseal XT (Ultradent Products Inc., South Jordan, UT) and Delton (Dentsply International, Woodbridge, Ontario, Canada) were chosen and tested for microhardness and abrasion resistance after they were polymerized. This study did not focus on the materials themselves, but rather the technique by which they were polymerized and what effect this had on the materials. Three separate light sources, a traditional halogen light (QHL 75, Dentsply International, Woodbridge, Ontario, Canada), and two newer LED lights (Ultralume LED, Ultradent Products Inc., South Jordan, UT; and 3M Freelight LED, 3M Corp, St Paul, MN) were used in this study. The materials were then cured with each light at each of three different distances: contact (0.5 mm), 2 mm, and 10 mm. The effects of light source variation and distance from the material at the time of polymerization was then evaluated for any significance to sealant placement technique. Specimens were tested for each variable combination of sealant material, light source, and distance between the two while curing. Six samples were tested for each variable grouping for abrasion resistance, and four separate san1ples were tested fron1 the san1e grouping for Knoop hardness. The results were analyzed for significance to determine if certain techniques are or could be beneficial or damaging to the quality of care provided by today's practitioners. RESULTS It was found that materials and light sources varied in combination and with different techniques (e.g., distance). In general, the top surface polymerized best when cured at a distance of 2 mm to 10 mm, while the bottom surface polymerized best at a distance of 0.5 mm. The halogen light consistently outperformed the two LED lights, with the 3M LED consistently producing the worst results. CONCLUSIONS The halogen curing light used in this study outperformed the LED lights in almost every category, despite the LED light manufacturer's claims of equality. For more reliable polymerization, the halogen light should be used. SIGNIFICANCE The practitioner must be aware of the material that he/she is using and how the chosen light source polymerizes that material. Manufacturers' claims and recommendations cannot be trusted to accurately produce the best results with every product on the market today, sometimes not even with the manufacturers' own products. It is crucial for practitioners to be well versed and knowledgeable about the products that they use, based on current research and not manufacturers' claims.Item Diluted antibiotics for treating traumatized immature teeth(2014) Sabrah, Ala'a Hussein Aref, 1984-; Platt, Jeffrey A., 1958-; Gregory, Richard L.; Hara, Anderson T.; Spolnik, Kenneth Jacob 1950-; Murray, Peter E.; Goebel, W. ScottEndodontic regeneration (ERP) has been successfully used in the treatment of traumatized immature teeth. The procedure has three essential steps: disinfecting the root canal (i.e. triple antibiotic paste (TAP) or double antibiotic paste (DAP)), provoking bleeding inside the canal to form a scaffold upon which pulp stem cells will be deposited and continue root growth, and creating a good coronal seal. Previous research has reported that antibiotic pastes (TAP and DAP) are cytotoxic to stem cells in the concentrations commonly used in endodontic regeneration (1000 mg/mL). To decrease the adverse effects on stem cells and increase the rate of success of the regeneration, defining appropriate antibiotic concentrations for ERP is critical. In this project, five in-vitro experiments were conducted to determine the breakpoint dilutions of both TAP and DAP medicaments, and to prepare a suitable novel pastes containing diluted TAP or DAP medicaments for ERP. In the first experiment, we compared the antibacterial effect of TAP, and DAP against early biofilm formation of Enterococcus faecalis (E. faecalis) and Porphyromonas gingivalis bacteria. In the second study, we investigated the antibacterial effect of various dilutions of TAP and DAP antibiotic medicaments against established E. faecalis biofilm. In the third experiment, we investigated longitudinally the residual antibacterial activity of human radicular dentin treated with 1000, 1 or 0.5 mg/ml of TAP and DAP. In the fourth study, we investigated the cytotoxic effect of various dilutions of TAP and DAP antibiotic medicaments on the survival of human dental pulp stem cells (DPSC). And in the fifth experiment, we investigated the antibacterial and cytotoxic effect of novel intracanal medicaments consisting of methylcellulose (MC) and/or propylene glycol (PG) mixed with 1mg/ml of TAP or DAP. 1 mg/ml of DAP or TAP medicaments had a significant antibacterial effect against early bacterial biofilm formation, and established bacterial biofilm. Furthermore, 1 mg/ml had a residual antibacterial activity comparable to 1000 mg/ml. The novel intracanal medicaments had comparable antibacterial effect to currently used medicaments (1000 mg/ml). Additionally, the novel intracanal medicaments significantly enhanced DPSC metabolic activity, compared to currently used medicaments in endodontic regeneration procedures.Item The effect of a novel photoinitiator system (RAP) on dental resin composites' flexural strength, polymerization stress, and degree of conversion(2009) Schaub, Kellie; Platt, Jeffrey A., 1958-; Andres, Carl J., 1942-; Levon, John A.; Brown, David; Hovijitra, Suteena, 1944-Objectives: A new technology has been introduced into the field of dental resin composites that professes to enhance light-curing efficiency. Rapid amplified photopolymerization (RAP) initiator technology has not yet been fully compared with resin composites with conventional initiators such as camphorquinone (CQ). The purpose of this study was to compare and contrast the effects of this novel technology (RAP) on properties of two light-cured resin composites. Flowable (EFQ) and microfilled (ESQ) experimental composites were fabricated and supplied from Tokuyama Dental with (w/RAP) and without RAP (w/o RAP). The flexural strength (MPa) and flexural modulus (MPa) were obtained using a three-point bending apparatus (Sintech Renew 1123, Instron Engineering Corp., Canton, MA). Polymerization stress curves were created using a tensometer (American Dental Association Health Foundation, NIST, Gaithersburg, MD) which were then used to calculate the maximum stress rate. Finally, the degree of conversion was measured using infrared spectroscopy (Jassco FT-IR spectrometer, Model: 4100, Jasco Corporation, Tokyo, Japan). When evaluating the flexural strength, the peak stress for EFQ w/RAP was significantly higher than EFQ w/o RAP (p = 0.0001). This was statistically not significant for the ESQ group, even though ESQ w/RAP did have a higher peak stress then ESQ w/o RAP (p = 0.28). The interaction between resin type and RAP was not significant when evaluating the flexural modulus (p = 0.21). Formulations with RAP had a significantly higher flexural modulus then w/o RAP (p = 0.0001). Experimental resins with RAP had significantly higher maximum stress rates than those w/o RAP when evaluating polymerization stress (p = 0.0001). Finally, groups w/ RAP appeared to have a higher degree of conversion than groups without (p = 0.0057). This study showed that the experimental composites with RAP had greater mechanical properties than those without. Unfortunately, the increase in polymerization stress causes concern clinically due to the chance of leakage at the restoration/tooth interface. One of the main potential disadvantages of this new RAP technology is an increase in the polymerization stress. Deciding if this amount of polymerization stress is clinically acceptable is yet to be accomplished.Item The effect of endodontic regeneration medicaments on mechanical properties of radicular dentin(2013) Yassen, Ghaeth H.; Platt, Jeffrey A., 1958-; Chu, Tien-Min Gabriel; Murray, Peter E.; Allen, Matthew R.; Vail, Mychel Macapagal, 1969-Endodontic regeneration treatment of necrotic immature teeth has gained popularity in recent years. The approach suggests a biological alternative to induce a continuous root development. In this project, three in vitro experiments were conducted to investigate the effect of three medicaments used in endodontic regeneration on mechanical properties and chemical structure of radicular dentin. In the first experiment, we investigated longitudinally the effect of medicaments on the indentation properties of the root canal surface of immature teeth using a novel BioDent reference point indenter. A significant difference in the majority of indentation parameters between all groups was found after one-week and one-month application of medicaments (p<0.0001): triple antibiotic paste (TAP) > double antibiotic paste (DAP) > control > calcium hydroxide [Ca(OH)2]. The four-week exposure of dentin to TAP and DAP caused 43% and 31% increase in total indentation distance outcome, respectively. In the second experiment, we investigated longitudinally the effect of medicaments on the chemical structure of immature radicular dentin by measuring the phosphate/amide I ratios of dentin using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy. Phosphate/amide I ratios were significantly different between the four groups after one week, two weeks and four week application of medicaments (p<0.0001): Ca(OH)2-treated dentin > untreated dentin > DAP-treated dentin > TAP-treated dentin. In the third experiment, we investigated longitudinally the effect of medicaments on root fracture resistance and microhardness of radicular dentin. For the microhardness, the two-way interaction between group and time was significant (p<0.001). TAP and DAP caused a significant and continuous decrease in dentin microhardness after one and three month application, respectively. The three-month intracanal application of Ca(OH)2 significantly increased the microhardness of root dentin. The time factor had a significant effect on fracture resistance (p<0.001). All medicaments caused significant decrease in fracture resistance ranging between 19%-30% after three month application compared to one week application. The three medicaments used in endodontic regeneration caused significant change in the chemical integrity of the superficial radicular dentin and significantly affected the indentation properties of the root canal surface. Furthermore, the three month intracanal application of medicaments significantly reduced the fracture resistance of roots.Item Effect of halloysite aluminosilicate clay nanotube incorporation into bonding agents on shear bond strength to human dentin(2013) Alkatheeri, Mohammed Saeed; Bottino, Marco C.; Chu, Tien-Min Gabriel; Platt, Jeffrey A., 1958-; Cook, Norman Blaine, 1954-; Cochran, Michael A. (Michael Alan), 1944-In adhesive dentistry, obtaining a good bond is a fundamental goal. It has been suggested that filler addition to the adhesives would increase the bonding strength of the adhesive layer. Halloysite aluminosilicate nanotubes (HNTs) are biocompatible, hydrophilic, durable, and have high mechanical strength. These advantages make them good candidates to be used as reinforcing agents for improving the properties of dental adhesives. The objective of this study was to evaluate the effect of incorporating HNTs into a commercial two-step etch-and-rinse adhesive system or one-step self-etch adhesive system on dentin shear bond strength. HNTs were incorporated into the two commercial adhesive systems in 0 wt%, 5 wt%, 10 wt%, and 20 wt%. The commercial control adhesives and the experimental adhesives were used to bond occlusal dentin of 120 extracted human molar teeth and then tested for shear bond strength by a universal testing machine with a semi-circular edge at a crosshead speed of 1.0 mm/min. Debonded specimens were examined under light microscopy to evaluate the fracture pattern. Resin-dentin interface were evaluated under scanning electron microscopy (SEM) after bonding dentin slabs using commercial control adhesives and experimental adhesive that showed numerically highest shear bond strength from each adhesive system. Two-way ANOVA was used to evaluate the effects of adhesive system and nanofiller content on shear bond strength. Pair-wise comparisons between groups were made using Fisher's (LSD) (p < 0.05). For the self-etch adhesive system, only incorporation of 5 wt% showed a significant increase in shear bond strength to dentin compared with the commercial control group. For the etch-and-rinse adhesive system, there was no significant difference in shear bond strength between HNTs filled adhesives groups and the commercial control group. Resin-dentin interface SEM evaluation showed nanotubes infiltrated into dentinal tubules. In conclusion, incorporating the self-etch adhesive system with 5 wt% HNTs increased the bond strength to dentin. Incorporation of up to 10 wt% filler concentration into both the self-etch and the etch-and-rinse adhesive systems did not adversely affect the bond strength to dentin or the handling properties. HNTs can penetrate along with resin tags into dentinal tubules, which could expand the use of their unique properties.Item Effect of surface conditioning methods on repair bond strength of microhybrid resin matrix composite(2010) Rajitrangson, Phitakphong, 1982-; Cochran, Michael A. (Michael Alan), 1944-; Cho, Sopanis D.; Gonzalez-Cabezas, Carlos, 1966-; Matis, Bruce A.; Platt, Jeffrey A., 1958-Repair is an alternative treatment option in many cases to replacement of resin matrix composite restoration. However, aged resin matrix composites have a limited number of carbon-carbon double bonds to adhere to a new layer of rein. Therefore, surface treatments of the aged resin matrix composite surface prior to repairing could improve the repair bond strength. The objectives of this study were to: 1) To evaluate various surface treatments on shear bond strength of repair between aged and new microhybrid resin matrix composite, and 2) To assess the influence of applying a silane coupling agent after surface treatments. Eighty disk-shaped resin matrix composite specimens were fabricated and thermocycled 5000 times prior to surface treatment. Specimens were randomly assigned to one of the three surface treatments (n = 20): 1) Airborne abrasion with 50 μm aluminum oxide, 2) Tribochemical silica coating (CoJet), or 3) Er,Cr:YSGG laser and control group (n = 20). Specimens were cleaned with 35-percent phosphoric acid, rinsed, and dried. Each group was assigned into two subgroups (n =10): a) no silanization, and b) with silanization. Adhesive agent was applied and new resin matrix composite was bonded to each conditioned surface. Bond strength was evaluated by shear test. Data were analyzed with a two-way ANOVA model. The interaction between conditioning and silanization was significant(p = 0.0163), indicating that comparisons of silanization must be evaluated for each conditioning method, and that comparisons of conditioning methods must be evaluated separately with and without silanization. Airborne particle abrasion showed significantly higher repair bond strength than Er,Cr:YSGG laser without silanization (p < 0.0001) and with silanization(p = 0.0002), and higher repair bond strength than the control without silanization (p < 0.00001) and with silanization (p < 0.00001). Airborne particle abrasion did not have significantly different in repair bond strength than Tribosilica coating without silanization (p = 0.70) or with silanization (p = 0.33). Tribosilica coating had significantly higher repair bond strength than Er,CR:YSGG laser without silanization (p < 0.0001) and with silanization (p < 0.0001), and significantly higher repair bond strength than control without silanization (p < 0.0001), but not with silanization (p =0.16). Er,CR:YSGG laser and control did not have significantly different repair bond strength without silanization (p = 1.00) or with silanization (p = 0.11). There was no effect of silanization on repair bond strength overall (p = 0.34) for any of the surface conditioning methods (p = 0.76 for airborne particle abrasion; p = 0.39 for tribosilica coating; p = 1.00 for Er,Cr:YSGG laser, or p = 0.39 for control). Airborne particle abrasion with 50-μm aluminum oxide particle and tribochemical silica coating followed by the application of bonding agent provided the highest shear bond strength values, suggesting that they might be adequate methods to improve the quality of the repairs of resin-matrix composites.Item Effect of surface treatments on microtensile bond strength of repaired aged silorane resin composite(2010) Palasuk, Jadesada; Platt, Jeffrey A., 1958-; Levon, John A.; Brown, David T.; Hovijitra, Suteera, 1944-; Cho, Sopanis D.Background: A silorane based resin composite, Filtek LS restorative, has been introduced to overcome the polymerization shrinkage of the methacrylate based resin composite. The repair of resin composite may hold clinical advantages. Currently, there is no available information regarding the repair potential of silorane resin composite with either silorane or methacrylate based resin composite. Objectives: The purpose of this study was to compare the repaired microtensile bond strength of aged silorane resin composite using different surface treatments and either silorane or methacrylate based resin composite. Methods: One hundred and eight silorane resin composite blocks (Filtek LS) were fabricated and aged by thermocycling between 8oC and 48oC (5000 cycles). A control (solid resin composite) and four surface treatment groups (no treatment, acid treatment, aluminum oxide sandblasting and diamond bur abrasion) were tested. Each treatment group was randomly divided in half and repaired with either silorane resin composite (LS adhesive) or methacrylate based resin composite (Filtek Z250/Single Bond Plus). Specimens were 12 blocks and 108 beams per group. After 24 hours in 37oC distilled water, microtensile bond strength testing was performed using a non-trimming technique. Fracture surfaces were examined using an optical microscopy (20X) to determine failure mode. Data was analyzed using Weibull-distribution survival analysis. Results: Aluminum oxide sandblasting followed by silorane or methacrylate based resin composite and acid treatment with methacrylate based resin composite provided insignificant differences from the control (p>0.05). All other groups were significantly lower than the control. Failure was primarily adhesive in all groups. Conclusion: Aluminum oxide sandblasting produced comparable microtensile bond strength compared to the cohesive strength of silorane resin composite. After aluminum oxide sandblasting, aged silorane resin composite can be repaired with either silorane resin composite with LS system adhesive or methacrylate based resin composite with methacrylate based dentin adhesive.Item The effect of triple antibiotic paste and EDTA on the surface loss and surface roughness of radicular dentin(2014) Nerness, Andrew; Spolnik, Kenneth Jacob, 1950-; Zunt, Susan L., 1951-; Platt, Jeffrey A., 1958-; Ehrlich, YgalIntroduction: Regenerative endodontic therapy in immature teeth with necrotic pulps triggers continued root development thereby improving the prognosis of these teeth. Several agents are under consideration for the disinfection and conditioning phases of this therapy. Triple antibiotic paste (TAP, i.e. equal parts of ciprofloxacin, metronidazole, minocycline) is used for canal disinfection and 17% EDTA solution is used for dentin conditioning. However, TAP and EDTA cause demineralization and their effect on surface loss and surface roughness of radicular dentin during regenerative procedures has not been quantified. Surface loss may be correlated with reduced tooth strength and surface roughness may be correlated with stem cell attachment. Objectives: The aim of this in vitro study was to quantitatively investigate the surface loss and surface roughness on human radicular dentin after treatment with two concentrations of TAP followed by EDTA. Materials and Methods: Human radicular dentin specimens were prepared from extracted human anterior teeth and randomized into six experimental groups. Group 1: saline control; Group 2: 17% EDTA; Group 3: TAP 1 mg/mL; Group 4: TAP 1 mg/mL and 17% EDTA; Group 5: TAP 1,000 mg/mL; Group 6: TAP 1,000 mg/mL and 17% EDTA for 5 minutes. After TAP is applied to Groups 3-6, all groups were incubated for 4 weeks. Then, groups 2, 4, and 6 were treated with EDTA for 5 minutes. Dentin surface loss (μm) and surface roughness (Ra, μm) were quantified after various treatments using non-contact and contact profilometry, respectively. Data were analyzed by one-way analysis of variance (α = 0.05) Hypothesis: It was hypothesized that there would be a significant difference in surface loss or surface roughness between at least two treatment groups. Results: All treatment groups showed significantly higher surface loss compared to untreated control. Dentin treated with 1g/mL TAP caused significant increase in surface loss and surface roughness compared to dentin treated with 1 mg/mL TAP. However, only 1g/mL TAP treated dentin showed significantly higher surface roughness compared to untreated control. The use of EDTA after both concentrations of TAP did not have significant additive effect on surface loss and surface roughness of dentin. Conclusion: The use of 1 mg/mL TAP can minimize surface loss and surface roughness of radicular dentin compared to higher concentrations. The use of EDTA after TAP may not cause additional surface loss and surface roughness of dentin.
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