Senior Dental Students’ Experience with Cariogram in a Pediatric Dentistry Clinic

The study objective was to assess predoctoral dental students’ experience with a caries risk assessment computer program in the pediatric dentistry clinic at Marquette University School of Dentistry. In 2005, spring semester sophomore dental students (class of 2008) were introduced to the caries risk assessment computer program “Cariogram.” The students received a fifty-minute lecture on caries risk assessment and a demonstration on how to use Cariogram in the clinic. After two years of clinical exposure to Cariogram, sixty-six out of eighty senior dental students completed an anonymous eleven-item questionnaire on their experience with the tool. Each item on the questionnaire was scored on a five-point Likert scale with the exception of two questions. Full- and part-time faculty members in the pediatric dentistry clinic were involved in teaching and supervising students in the use of Cariogram for caries risk assessment after their training and calibration. Forty-five percent of the students who participated in the study agreed that Cariogram was easy to understand, and 18 percent disagreed. Thirty-six percent felt that it was easy to apply, and 25 percent reported that it was useful in determining caries preventive procedures. The students reported that 60 percent of full-time and 33 percent of part-time faculty were knowledgeable about Cariogram use. A majority of the students felt that Cariogram was not easy to understand, and eighty-two percent of them reported that they would not be using Cariogram in their private offices. Future studies should explore reasons why students do not feel inclined to use Cariogram as a caries risk assessment tool in their private practices even after being exposed to the tool in dental school

Developing Consistency in Enamel Etching by CO\u3csub\u3e2\u3c/sub\u3e Laser

It has been reported that CO2 laser energy can be utilized to etch enamel. However, consistency of etching has been a significant problem. This research was designed to ascertain which exposure parameters result in consistent etching of enamel. Fourteen non.carious teeth were selected and a 2x4 gridwork was cut into the buccal surfaces creating eight discrete windows for laser exposures. Four teeth served for the initial pilot project. Two windows were lased at each combination of exposure parameters. Laser exposures were at .01, .02, .05, or .10 sec. at 2, 5, 10, or 15 Watts (W) with a model 20C Pfizer CO2 laser. A 1.0mm focal spot was used throughout. Following SEM examinations, it became clear that etching occurred only at .05 and .10 sec. at 10 and 15W. Ten teeth were used for the main project at .05 and .10 sec. exposures at 10 and 15W. Ten windows were lased for each combination of exposure parameters. SEM analysis was accomplished at 100X and 1,200X. 10/10 laser exposures at .05 sec./15W, .10 sec./10W and .10 sec./15W resulted in etched enamel. Statistical analysis showed a significant difference in etching between the .05 sec.10W group and the higher exposure parameters (p= .003). The results indicate that CO2 laser energy can consistently etch enamel at .10 sec. at 10 or 15W and at .05 sec. at 15W with a 1.0mm focal spot

Response of Three Cultivars of Bell Pepper (Capsicum Annuum L.) to Mulching & Irrigation

The effect of black polyethylene mulching and drip irrigation on the yield and quality of three cultivars of bell pepper was studied during the 1987 growing season. This study was conducted on a Pembroke silt loam soil on the Western Kentucky University Farm in Bowling Green, Kentucky. The experimental design was a split-plot arranged in randomized complete blocks in four replications with treatment as the main plot and cultivars as the sub-plot. \u27California Wonder,\u27 \u27Lady Bell F1 Hybrid: and\u27 Keystone Resistant Giant\u27 cultivars of bell pepper were established in the field during the last week of May. The cultivars were grown using black polyethylene, with application of irrigation (no mulch) and without irrigation or mulch (check) Irrigation was initiated in early August and continued throughout the remainder of the growing season; the amount per application was 158.8 m3/ha. At harvest, mature green fruit were removed from the plant, weighed, and classified as grade I or II. There were significant differences at the 5% level in the yield of the cultivars. There were significant differences at the 5% levels among the yields of the treatments. the higher yield was obtained with irrigation, followed by the use of mulch. The better yield under each of the three treatments was obtained with the cultivar Lady Bell. The production of grade II peppers Was higher than the production of grade I peppers, the average yield was 48.82 MT/ha, and 21.99 MT/ha, respectively. The yield of bell pepper grade II was higher in all three treatments

Effect of Three Different Contamination Removal Methods on Bond Strength of Ceramic To Enamel Contaminated With Aluminum Chloride and Ferric Sulfate

Background: The need to control moisture and contamination is crucial in adhesive dentistry, especially when rubber dam isolation is not feasible. Hemostatic contamination can negatively affect adhesion to tooth substrate. To achieve better outcomes, hemostatic agents should be rinsed off properly using a method that will remove the contamination and will not affect the μ-SBS. Objective: To evaluate and compare the effect of three different aluminum chloride and ferric sulfate contamination removal methods on the μ-SBS of lithium disilicate glass-ceramic bonded to enamel and to compare the type of fracture between samples. Material and Methods: Lithium disilicate blocks (IPS e.max CAD) were cut into samples of 2 mm in diameter and 3mm in height. Thirty-five human molar teeth were collected and separated into seven groups (n=17) Groups: G1(control): No contamination. G2: Contamination with aluminum chloride and removal by 30 seconds water-rinse. G3: Contamination with aluminum chloride, removal by re-etching (37.5% phosphoric acid), water-rinse. G4: Contamination with aluminum chloride, removal with 18% EDTA G5: Contamination with ferric sulfate, removal with water-rinse. G6: Contamination with ferric sulfate, removal by re-etching (37.5% phosphoric acid), water-rinse and dried. G7: Contamination with ferric sulfate, removal with 18% EDTA. The enamel surface was etched, then contaminated with aluminum chloride and ferric sulfate, cleaned using 3 different methods, previously described. Ceramic samples were etched with HF acid, silanated then bonded to enamel surface using Optibond FL, Variolink veneer cement and the Elipar S10 curing light, to avoid oxygen inhibition restoration margins were cover with a glycerin to complete polymerization of 10 -30 seconds each side. Specimens were stored in deionized water for 7 days, then subjected to μ-SBS testing, fractured specimens were examined with a stereomicroscope to determine the type of fracture, and five sample of each group were selected for SEM. To compare differences for the outcome a general linear mode ANOVA was created, and data recorded. Results: There were statistically significant differences among the studied groups for the μ-SBS (p\u3c 0.05). The G6 (Ferric sulfate- Re-etching) was the closest mean μ-SBS (10.75 MPa) to the G1(control group).μ-SBS (16.24 MPa), the lowest μ-SBS (6.13 MPa) for the G4 (Aluminum chloride-EDTA). The groups using ferric sulfate as a cleaning method presented higher μ-SBS MPa than the groups using aluminum chloride as a cleaning method. The type of fracture on groups with higher μ-SBS (MPa), G6 - 10.75 MPa (ferric sulfate-reetching), G5 - 9.21 μ-SBS(MPa) (Ferric sulfate-water) presented more cohesive fractures, while groups with lower μ-SBS(MPa), G4 – 6.13 MPa (Aluminum chloride- EDTA), G3 – 6.27 (aluminum chloride- re- etching) presented more mixed fractures. Conclusions: The present study sought to investigate the effect of three different contamination removal methods on bond strength of ceramic to enamel contaminated with aluminum chloride and ferric sulfate. Ferric sulfate hemostatic agent showed higher μ-SBS in all contamination removal methods when compare to aluminum chloride hemostatic agent. But all the contamination removal methods in both groups failed to increase the bond strength on enamel to the level of the control group. Further research is required before we can make definitive conclusion

Nanomedicine in Cancer

Non

Synthesis of Gemcitabine Analogues with Silicon-Fluoride Acceptors for 18F Labeling

Gemcitabine (dFdC) is an effective chemotherapeutic nucleoside analogue for treatment of cancers and solid tumors. Gemcitabine’s chemotherapeutic effect is limited by its rapid intracellular deamination by cytidine deaminase into the inactive uracil derivative. Herein, I designed and synthesized two sets of gemcitabine analogues: i) a 4-N-alkyl gemcitabine analogue containing a β-keto sulfonate moiety, and ii) clickable analogues possessing silicon-fluoride acceptor building blocks. Both of these sets of analogues undergo efficient fluorination, including fluorination protocols compatible with 18F labeling. The synthesis of the 4-N-alkyl gemcitabine analogue bearing β-keto sulfonate moiety began with reaction of 4-N-tosylgemcitabine with 1-amino-10-undecene, followed by a series of oxidation and sulfonation steps which yielded the β-keto sulfonate analogues. The coupling of gemcitabine with carboxylic acids using peptide coupling conditions afforded 4-N-alkanoyl analogues with a terminal alkyne or azido moiety. Click reaction of these 4-N-alkanoyl analogues with dialkylsilyl building blocks gave 4-N-alkanoylsilanegemcitabine analogue. Reaction of 4-N-tosylgemcitabine with vii functionalized azidoalkyl amines provided 4-N-alkylgemcitabine with a terminal azido group. Coupling of the latter with dialkylsilyl building block provided 4-N-alkylsilanegemcitabine. Fluorination of 4-N-alkyl gemcitabine analogues with β-keto sulfonate moieties and of the trisubstituted silane derivatives with KF and 18-Crown-6 (CH3CN/75°C/0.5-1h), gave the corresponding fluorinated 4-N-alkyl and alkanoyl gemcitabine analogues under conditions that are compatible with protocols for positron emission tomography (PET) 18F labeling. The [18F] 4-N-alkyl and alkanoyl silane gemcitabine analogues were successfully synthesized on microscale and macroscale radiochemical protocols. The biodistribution of [18F] 4-N-alkyl gemcitabine analogue was analyzed via PET imaging. The cytotoxicity activity of the silane gemcitabine analogues were studied in cancer L1210 and HEK293 cell lines and their cellular uptake were investigated using HPLC analysis and fluorescence microscopy. Reduction of ribono-1,4-lactones and gulono-1,4-lactone as well as ribono-1,5-lactone and glucono-1,5-lactones with LTBH (1.2 equiv.) in CH2Cl2 at 0 °C for 30 min provided the corresponding pentose or hexose hemiacetals in chemoselective fashion and in high yields. Commonly used in carbohydrate chemistry protecting groups such as trityl, benzyl, silyl, acetals and to some extent acyls are compatible with this reduction