A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. Introduction: Panoramic radiographs are used extensively in the practice of orthodontics. They are used at the beginning of treatment to evaluate tooth presence, development and location, as well as, pathology, and the general location of anatomic structures. Panoramic radiographs are used during and after treatment to monitor those conditions as well as to assess the progress of the treatment such as the parallelism of the roots of teeth. Although the accuracy of panoramic radiographs in evaluating root parallelism has been questioned, the use of the panoramic radiographs to evaluate root parallelism is still common practice in orthodontics. Objective: To evaluate the effects the buccolingual inclination of teeth has on the projected mesiodistal angulation or root parallelism presented in panoramic radiographs. Materials and Methods: Using a dental typodonts the dentitions were bracketed using 0.022" x 0.028" ceramic brackets. The typodonts were fabricated so that between both of them the maxillary and mandibular experimental teeth from lateral incisor to second premolar were free to move about an axis surrounding the bracket and the archwire. A 0.021" x 0.025" stainless steel archwire was used to establish a "standard" buccolingual position for the moveable teeth. A 0.020" stainless steel archwire was then used to allow for buccolingual rotation to occur. The moveable teeth had their mesiodistal angulation and buccolingual inclination measured with a coordinate measuring machine (CMM). The teeth were positioned and measured at five degree increments in the buccolingual direction to +/- 20 degrees. At each buccolingual inclination the mesiodistal angulation was measured with the CMM. Panoramic radiographs were taken in each position. The mesiodistal angulation was then measured on the radiographs. The actual mesiodistal angulations recorded with CMM were then compared with the angulations on the panoramic radiographs. Results: A Wilcoxon sign rank test was run on the data to evaluate statistical differences. Statistically significant differences were seen at the buccolingual inclinations of +15, +20, and -20 degrees. In comparing the difference between the CMM measurements and the comparable panoramic measurements 63 percent fell outside of the clinically acceptable range of +/- 2.5 degrees. Conclusions: Caution should be taken in evaluating root parallelism with panoramic radiographs. The buccolingual inclination can affect the mesiodistal projection on panoramic radiographs. The areas of the canines and first premolars are especially susceptible to distortion.

Craniofacial tissue loss due to traumatic injuries and congenital defects is a major clinical problem around the world. Cleft palate is the second most common congenital malformation in the United States occurring with an incidence of 1 in 700. Some of the problems associated with this defect are feeding difficulties, speech abnormalities and dentofacial anomalies. Current treatment protocol offers repeated surgeries with extended healing time. Our long-term goal is to regenerate bone in the palatal region using tissue-engineering approaches. Bone tissue engineering utilizes osteogenic cells, osteoconductive scaffolds and osteoinductive signals. Mesenchymal stem cells derived from human umbilical cord (HUMSCs) are highly proliferative with the ability to differentiate into osteogenic precursor cells. The primary objective of the study was to characterize HUMSCs and culture them in a 3D hydrogel scaffold and investigate their osteogenic potential. PuraMatrixTM is an injectable 3D nanofiber scaffold capable of self-assembly when exposed to physiologic conditions. Our second objective was to investigate the effect of Bone Morphogenic Protein 2 (BMP2) in enhancing the osteogenic differentiation of HUMSCs encapsulated in PuraMatrixTM. We isolated cells isolated from Wharton's Jelly region of the umbilical cord obtained from NDRI (New York, NY). Isolated cells satisfied the minimal criteria for mesenchymal stem cells (MSCs) as defined by International Society of Cell Therapy in terms of plastic adherence, fibroblastic phenotype, surface marker expression and osteogenic differentiation. Flow Cytometry analysis showed that cells were positive for CD73, CD90 and CD105 while negative for hematopoietic marker CD34. Alkaline phosphatase activity (ALP) of HUMSCs showed peak activity at 2 weeks (p

Objective: The purpose of this ex vivo study was to assess the changes in tooth color and existing orthodontic bracket bonding when exposed to a bleaching agent. Methods: 120 freshly extracted human premolars were equally divided into 4 groups: a negative-control group, a positive-control bleaching group, a bracket-bonded group, and a bracket bonded-bleached group. The bleaching protocol was carried out as recommended by the manufacturer of Opalescence Go® – 30 minutes each day for 10 consecutive days. The color value of each tooth was measured daily by spectrophotometry for the negative-control group and the positive-control bleaching group in 6 different locations: central, occlusal, left, right, gingival, and lingual. The color values of the bracket-bonded group and bracket-bonded bleached group were measured initially at day 1 and after the debond test and removal of remaining composite at day 11. At the end of bleaching, the changes in existing bracket bonding were assessed by measuring shear bond strength (SBS), adhesive remnant index (ARI), and the number of tooth fractures during debond testing. Results: This orthodontic-specific bleaching system bleached teeth with no brackets bonded, comparing color values of the negative-control group and the positive-control bleaching group. However, it did not show an added whitening effect on teeth with existing brackets at the central, occlusal, and gingival sites, comparing the color values of the bracket-bonded group and the bracket-bonded bleached group. There were no statistically significant differences noted on SBS and ARI between the bracket-bonded group and the bracket bonded-bleached group. To our surprise, the bracket-bonded bleached group showed a statistically significant increase in the rate of tooth fracture during debond (33%), compared to the bracket-bonded group (10%). Conclusions: Using this bleaching protocol on teeth with existing bonded brackets did not have an added whitening effect at central, occlusal, and gingival sites. The added whitening effect was only noted at left, right, and lingual sites. Especially with no significant difference in the color values at the central sites, which were underneath the bonded brackets, there was no added bleaching effect with the use of this bleaching system on the teeth with existing bonded brackets. The bleaching did not show a significant effect on bracket bonding SBS or ARI. However, it may compromise the tooth structure and lead to an increase in enamel fractures during debond.

Objective: This study aims to evaluate the dimensional precision of orthodontic buccal tubes slots from different orthodontic companies using the Scanning Electron Microscope (SEM). Methods: Four of the most popular orthodontic companies within the US who manufacture and distribute molar tubes to orthodontists were selected for this study including Opal (Ultradent), Ormco(Damon), American Orthodontics and 3M Unitek. Each company was asked to send 20 molar tubes, 022 slot (.0225 x .0285 inches), which have been manufactured within the past 2 months to be used in this study. We measured the accuracy of individual tube dimensions in relation to their respective company catalogs, as well as document any defects observed within these tubes. Descriptive statistics, means and standard deviations were calculated for all buccal tubes from the four companies and for each wall of the respective tubes. In the first analysis, a 1-way ANOVA with Bonferroni pairwise comparisons was conducted, using a level of significance of 0.05. A box-plot was included to illustrate these variables. In the second analysis, the measurements relating to dimensions of tubes were compared with the acceptable parameters of the .0225 x .0285 inches slot. This comparison was conducted using Fisher's exact test and Cramer's V test (Correlation), using a level of significance of 0.05. Pie charts were used to illustrate the percentiles of tubes with dimensions that fall within the acceptable parameters of .0225 x .0285 slot. Results: All four companies produced slots that were on average over-sized. There was no consistency in meeting the standards of dimensions when comparing each of the four walls for each company. However, a higher percentage of American orthodontics and 3M tubes met the standards of measurement of the occlusal and gingival walls. All tubes were convergent from mesial to distal and lingual to buccal direction. Conclusions: All companies manufactured over-sized tubes.There was no consistency in dimensional accuracy of tubes produced by any of the four companies. All tubes were convergent from mesial to distal and lingual to buccal dimension.

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. Introduction: The association between occlusal characteristics and Temporomandibular Disorders (TMD) has been previously investigated, however, debate still exists. Objective: To compare the occlusal characteristics of subjects with anterior disc displacement with reduction (ADDR) to that of asymptomatic controls. To investigate whether an association exists between specific occlusal characteristics and ADDR. Materials & Methods: 99 de-identified dental casts (68 ADDR subjects and 31 asymptomatic subjects) from Tufts University School of Dental Medicine were analyzed. Eleven occlusal characteristics were evaluated for each set of casts: 1. Angle's dental classification of malocclusion 2. overjet 3. overbite 4. intercanine distance 5. intermolar distance 6. curve of spee 7. arch form 8. tooth size arch length discrepancy 9. crossbite 10. Bolton discrepancy 11. premolar extractions. Results: Significant associations were found between bilateral AADR and a tapered arch form (p<0.05). In addition, there was a significant association between an ovoid arch form and the absence of ADDR (p<0.05). The mandibular intercanine distance of subjects with bilateral ADDR was smaller than those with unilateral ADDR (left TMJ) (p<0.05). Anterior mandibular crowding was significantly greater for the bilateral ADDR group when compared to the group with no ADDR (p<0.05). Furthermore, there was a greater amount of anterior mandibular crowding for the bilateral ADDR group compared to the unilateral ADDR group (left TMJ) (p<0.05). Conclusions: Although multiple occlusal characteristics have been investigated in relationship to TMD, arch form has not been previously reported on. In the present study, a tapered arch form, anterior mandibular crowding and mandibular intercanine distance were significantly associated with ADDR. Although occlusal variables are unlikely to be the only contributing factor to TMD, their role should not be overlooked. The findings of this study suggest possible directions for future research.

Several recent longitudinal studies of large community populations have revealed that people with more extensive network resources live longer. However, it is not known whether this occurs because social ties prevent disease or retard its progression once it occurs. The purpose of this research was to: (1) determine the relationship between social network indicators and mortality in an urban sample; (2) extend that knowledge by addressing the relationship between networks and disease incidence and disease progression; (3) delineate which specific network sectors were the strongest predictors of the health related outcomes. This was uniquely possible because measures of the three dependent variables were available within the same data set at the Kaiser Permanente Center for Health Research. The research design was longitudinal, based on survey data. The conceptual framework posited that social support delivered via social networks modifies disease states. The setting was the Northwest Region, Kaiser Permanente Health Care Plan, an HMO serving the Portland/Vancouver SMSA. The sample included 2603 adults who participated in a 1970 household interview survey. Their health service utilization data from 1967-73 has been computerized and linked with the survey information. As of 1982, 376 have died. To measure the independent variables, four summary social network indexes (scope, size, frequency of contact, and interaction) were prepared according to a network model based upon the survey questions available, network theory, and prior research. Indexes representing nine relationship domains were constructed. Control variables included age, sex, SES, health status indicators, and health behaviors. Multiple logistic regression was used to assess hypothesis 1 and ordinary regression was used to assess hypotheses 2 and 3. Each of the four summary network measures was a statistically significant predictor of 12 year mortality. Network scope was the strongest predictor. Marital, family, and kin relationships were not predictive of death. Extended ties of close friends, other friends, work associates, and social leisure activities were significant predictors. No relationship was found between network scope, disease incidence, or disease progression, so it is still unclear how social connections act to decrease mortality.

The fate and transport of insoluble, hydrophobic organic pollutants in the aquatic environment constitutes a prominent area of concern. It is thought that pollutants of this nature may exist in association with organic carbon, which is predominantly aquatic humus. This type of association could significantly affect the kinetics of such transformation processes as volatilization or chemical and biological degradation of the pollutant. While dissolved organic matter (DOM) comprises the bulk of organic carbon (or aquatic humus) in natural waters, the interaction between naturally occurring DOM and insoluble organic pollutants has not been quantified. The work presented in this dissertation is an effort to quantify the effect of dissolved organic matter on the solubility in water and, hence, the transport of hydrophobic organic compounds (specifically, DDT) in the environment. Saturated aqueous solutions of DDT were generated by a method that is different from those used by other workers. Within a closed system, an excess of solid DDT was allowed to vaporize and enter an aqueous solution through the gas phase. The concentration of DDT in solution increased with time, leveling off when equilibrium and a saturated solution was established. The solubility of p,p'-DDT in distilled water was determined to be 1.87 (+OR-) .01 ppb. The solubility of the o,p'-DDT isomer in distilled water was determined to be 4.88 (+OR-) .03 ppb. The concentrations of p,p'-DDT and o,p'-DDT in distilled water solutions containing dissolved organic matter were definitely higher than the aqueous solubilities of these compounds. A minimum value for the DDT/DOM partition coefficient (K(,p)) in water was determined. This partition coefficient, when normalized to organic carbon, is referred to as K(,oc) (K(,oc) = K(,p)/fraction organic carbon). A minimum log K(,oc) for both p,p'-DDT and o,p'-DDT was determined to be 4.7 (+OR-) .2 log units. Under environmental conditions, this partition coefficient indicates that the majority of DDT present in aqueous systems will be associated with dissolved organic matter.

Leaf and bark extracts of a Mexican medicinal plant, Byrsonima crassifolia (Malpighiaceae), exhibited spasmogenic effects on isolated rat fundus and biphasic effects on jejunum and ileum. Preliminary evaluations using rat fundus in Krebs solution indicated that the activity of a 2% acetic acid extract of eaves (HOAcE) could be split into two types: (i) high-efficacy, low-potency, n-butanol-extracted, pargyline- and 1-(1-naphtylpiperazine) (1-NP)-sensitive, atropine-insensitive activity, and (ii) low-efficacy, high-potency, ethyl acetate-extracted, pargyline-insensitive, atropine- and 1-NP-sensitive activity. HOAcE lacked muscarinic and nicotinic effects on rat jejunum and frog rectus abdominis. Serotonin (5-HT) and HOAcE curves in fundus were parallel and 5-HT potency was 6,037 times that of HOAcE (95% confidence limits: 4,624-7,852). The pD$\sb2$ (affinity constant) for 5-HT was 7.96 (7.92-8.00) with pargyline added to the medium. 5-HT receptor-interaction kinetics using cholinergics and 5-HT agonists and antagonists was carried out. 1-NP competitively antagonized 5-HT. The 5-HT, antagonist s-(-)propranolol did not significantly antagonize 5-HT. The 5-HT$\sb2$ blocker ketanserin noncompetitively antagonized 5-HT and $\alpha$-Me-5-HT (pD$\sp\prime$2 = 5.6 and 6.7, respectively). The 5-HT$\sb3$ antagonist MDL-72222 inactivated only a small proportion of receptors (pD$\sp\prime$2 = 6.46). Atropine did not significantly modify the curve of 5-HT while fluoxetine noncompetitively antagonized 5-HT (pD$\sp\prime$2 = 5.8). 5-HT and $\alpha$-Me-5-HT curves were biphasic indicating two receptor interactions (high and low affinity). High-affinity pD$\sb2$ values for six different 5-HT agonists and 1-NP on rat fundus correlate well with reported rat brain (radioligand binding) pKd values at the 5-HT$\sb{\rm 1C}$ receptor (r = 0.94). Large scale extraction and fractionation of a methanol extract of leaves yielded two peaks of activity (Peak 1, lipophilic; Peak 2, polar). Peak 1 contained Compounds 1 to 7 (C1-C7); Peak 2 included C8-C15. Compound 1, C2, C3, C4, C10 and C11 were inactive while C8, C12 and C13 showed equivocal effects. Compound 5, C6, C7, C9, C14, C15, quercetin and gallic acid were active. Potencies were: C5 $>$ C6 $>$ C7 = quercetin $>$ C9 $>$ gallic acid. Efficacy (IA) was: C15 $\geq$ C14 $>$ gallic acid $>$ C9 $>$C5 $>$ C7 $>$ quercetin $>$ C6. Compound 9 and its aglycone quercetin were partial agonists (C9 IA = 70%, pD$\sb2$ = 6.35; quercetin IA = 60%, pD$\sb2$ = 6.58). Compound 9 noncompetitively antagonized 5-HT (pD$\sp\prime$2 = 6.10), while quercetin did not. Compound 14 and C15, the most active compounds, had similar response curves but these curves were not parallel to 5-HT. Spasmogenic ED$\sb{50}$ values for C14 = 0.76 (0.38-1.54) $\mu$g/mL and C15 = 0.76 (0.41-1.42) $\mu$g/mL. Gram for gram 5-GT was 181 $\times$ C14 and 182 $\times$ C15.

Effects of solubility, partition coefficient, pH and selected adjuvants (propylene glycol and Azone) on the percutaneous penetration of isoproterenol HC1 in vitro have been investigated using human cadaver skin. Preliminary stability studies demonstrated that isoproterenol HC1 was very stable (less than 1% decomposition) for 24 hours at 22(DEGREES) (+OR-) 0.5(DEGREES) in the pH range 1 to 7 in the following solvents: water, normal saline, propylene glycol and a series of propylene glycol-water mixtures (10,20,40 and 60% v/v). The rate of decomposition of the drug in aqueous solutions increased with pH beyond pH 8. In normal saline, the decomposition was significant when the temperature was raised to 37(DEGREES) (+OR-) 0.5(DEGREES). The solubility of isoproterenol HC1 decreased and its skin/vehicle partition coefficient increased with increasing proportions of propylene glycol in the vehicle. Results of the physicochemical and percutaneous penetration studies revealed that 20% v/v propylene glycol in water should be the optimal vehicle for transdermal delivery of isoproterenol HC1. Optimal penetration enhancing effects of AzoneR were seen when incorporated at a concentration of 1% v/v in the 20% v/v propylene glycol-water vehicle and more dramatically when the skin was pretreated with pure Azone for 60 minutes prior to application of the drug formulation. The flux reached a maximum around pH 9 in agreement with the predicted favorable pH environment for neutral forms of isoproterenol HC1. Both neutral and charged forms of isoproterenol HC1 were found to contribute to the total flux in agreement with the proposed model: J = ( Kp . C )ca + ( Kp . C )an + ( Kp . C )n. The calculated permeability coefficients for isoproterenol HC1 were 0.2098 x 10-3, 0.1570 x 10-4 and -0.8665 x 10-3 cm/h for neutral, cationic and anionic species, respectively. Azone enhanced the penetration of all forms of isoproterenol HC1, although the effect was more pronounced on the anionic species. This may be due to facilitation of penetration by formation of an ion-pair between isoproterenol HC1 and Azone. The permeability coefficients for the neutral, cationic and anionic forms of isoproterenol HC1 for penetration through Azone-pretreated skin were 0.8395 x 10-3, 0.1701 x 10-3 and 0.8091 x 10-2 cm/h, respectively.

To investigate the mechanism of polyamine- and acetylpolyamine-induced vasodilation, aortic rings from anesthetized New Zealand white rabbits (2.0-2.5 kg) were incubated in modified Krebs-Henseleit buffer, precontracted with phenylephrine (PE), and isometric tension measured. Concentration-response curves were constructed for polyamines (putrescine, spermidine, and spermine) and acetylpolyamines ($N\sp1$-acetylputrescine, $N\sp1$-acetylspermidine, $N\sp8$-acetylspermidine, and $N\sp1$-acetylspermine) in both endothelium-intact and -denuded rings. In both types of rings, all polyamines and acetylpolyamines except $N\sp1$-acetylputrescine produced concentration-dependent relaxation (potency, spermine $>$ spermidine $>$ putrescine for polyamines; $N\sp1$-acetylspermine $>\ N\sp1$-acetylspermidine $>$ $N\sp8$-acetylspermidine for acetylpolyamines). The inhibition of endothelium-derived relaxing factor (EDRF)/nitric oxide (NO) by reduced hemoglobin and $N\sp\omega$-nitro- sc L-arginine methyl ester (sc L-NAME), and the inhibition of soluble guanylate cyclase by methylene blue did not affect the ability of polyamines or acetylpolyamines to relax vascular smooth muscle with and without endothelium, respectively. Indomethacin had no effect on polyamine- or acetylpolyamine-induced vasodilation in endothelium-intact aortic rings. In endothelium-denuded rings, Ca$\sp{2+}$ agonist, Bay K 8644, induced concentration-dependent contraction in segments of rabbit aorta, partially depolarized with 15 mM KCl. This was blocked by Ca$\sp{2+}$ antagonists, nifedipine and verapamil, and polyamines and acetylpolyamines in a concentration-dependent manner, shifting the concentration-response curve of Bay K 8644 to the right. Polyamines and acetylpolyamines as nifedipine and verapamil shifted concentration-response curves of K$\sp+$ and PE to the right in a concentration-dependent manner. Polyamines and acetylpolyamines also decreased contractions invoked by the Ca$\sp{2+}$ ionophore A23187. The concentration-dependent contraction curve for exogenous Ca$\sp{2+}$ in K$\sp+$-depolarization medium (K$\sp+$ = 120 mM) was shifted to the right by polyamines and acetylpolyamines. Both polyamines and acetylpolyamines also reduced the potentiation of K$\sp+$-induced contraction and Ca$\sp{2+}$ concentration-dependent contraction induced by Bay K 8644. The results indicate that polyamines and acetylpolyamines, as endogenous vasodilators, dilate vascular smooth muscle independent of EDRF/NO, vasodilatory prostaglandins, and by activation of soluble guanylate cyclase. Furthermore, these results suggest that polyamines and acetylpolyamines may relax vascular smooth muscle at the plasma membrane level by a mechanism that involves Ca$\sp{2+}$ influx, although may other mechanism may be possible. Further studies are needed to determine if polyamines and acetylpolyamines have calcium antagonistic properties that are involved in the mechanism of vasodilation of rabbit aortic vascular smooth muscle.