As the proportion of adults aged 65 years and older continues to grow across the globe and edentulism rates decline, there is widespread concern about a rise in the prevalence of periodontal disease, characterized by chronic inflammation of tooth-supporting tissues induced by persistent infection. Compared to their younger counterparts, older adults experience a higher burden of periodontal disease, which can result in tooth loss, poor nutritional intake, higher prevalence of other chronic diseases, and a decrease in overall quality of life. While cross-sectional studies have underscored the role of chronic stress on periodontal disease progression in older adults, longitudinal evidence is currently lacking. This dissertation draws on prospective data from a birth cohort of older Danish adults (1914 Glostrup Aging Study) with 25 years of follow-up. Using physiological markers than span the metabolic, inflammatory, and cardiovascular systems, I developed a composite measure of allostatic load (AL) at age 80, defined as the cumulative biological damage that results from a whole-body adaptation to chronic stress. First, I identified social and behavioral predictors of high scores on AL. In men, those with no vocational training, unskilled occupation, low income, and a sedentary lifestyle were more likely to have high AL, consistent with a "weathering" pattern of biological systems resulting from chronic adversity over the life course. To test the hypothesis that high AL is longitudinally associated with periodontal disease, I evaluated bidirectional longitudinal associations using multiple measures of AL and periodontal disease. Results showed a positive nonlinear association of AL at age 70 with periodontal disease at age 85, but no association between periodontal disease at age 70 with AL at age 80. This finding confirms previous cross-sectional data, and supports the role of chronic stress on infection-induced inflammation. To test the hypothesis that high AL is associated with mortality risk, I examined this association longitudinally from ages 70 - 95. Compared to low AL, high AL was positively associated with all-cause mortality, and even stronger when cardiovascular disease mortality was considered. AL-mortality associations were higher among those who were dentate as compared to edentate, suggesting that dentate status modifies the relationship. Findings from this dissertation contribute to our understanding of the consequences of stress on periodontal disease in relation to aging and offer potential avenues for intervention.

Intra-oral  halitosis  (bad  breath)  is reported  to affect  15-83 % of the adult population. Having intra-oral halitosis is a social and psycho-logical handicap, and may cause people in the  person’s social circle to increase the physical distance or to turn their faces in another direction to avoid the unpleasant smell from the exhaled air. Such behaviours may affect the individual’s self-confidence resulting in insecurity in social and intimate relations. The oral health-related quality of life status has also been reported to be lower in individuals with halitosis. Approximately 90% of what is considered as bad breath is the result of the degradation of organic substrates (proteins) by an- aerobic bacteria of the oral cavity. Intra-oral halitosis can be  assessed using both subjective and objective methods to evaluate the subject’s exhaled air. The most common one and the one often referred to as the ”gold standard”, is the organoleptic scoring system (OLS). OLS is a subjective method  evaluating  the  strength  of halitosis in exhaled air using a scale from 0-5. One objective  method to assess the presence of volatile sulphur compounds in exhaled air is to use a sulphide monitor measuring the total sum of the volatile sulphur  compounds  (T-VSC) in exhaled  air.  The three  gases  (hydrogensulphide (H2S), methyl mercaptan (MM) and dimethyl sulphide (DMS)) in exhaled air related to intra-oral halitosis can be assessed separately using a simplified gas chromatograph. Different treatment models such as periodontal treatment, tongue scraping and rinsing with Zn ion containing products have been used to reduce intra-oralhalitosis. The  present  thesis  has  evaluated  the  efficacy of  different treatment models in the treatment of intra-oral  halitosis.

No description available.

Objective : To determine if the linear measurements made in Galileos CBCT in the presence of soft tissue using cadaver heads are accurate. Materials and methods : CBCT images were obtained in Galileos CBCT device after placement of gutta percha markers, three to the facial and one to the lingual of the area of interest in the mandible. The CBCT orthoradial image showing perfect alignment of the lingual with a facial marker was selected as the plane of measurement. The distance between the most superior and most inferior point on the bone on the selected plane was measured electronically. The specimens were sectioned along this plane and physical measurements were obtained with digital calipers. Linear distance was measured between the most superior and most inferior point on the bone on the selected plane. This distance was measured in 6 specimens with calipers and compared to the distance measured on the corresponding CBCT images. Results: A paired-sample t-test was used to determine whether the mean difference measurement value of two measurements at right side was significantly equal to zero. The data revealed that overall there was no statistically significant difference between CBCT and Physical measurement on right side (p=0.2298), left side (p=0.3554) and overall between CBCT and Physical measuremnets (p=0.2684). Conclusions: Based on the statistical evaluation of the CBCT and Physical measurements it can be concluded that Galileos CBCT unit is reliable for evaluation of linear measurements between anatomic structures within the bone in the presence of soft tissues in the mandible specially for measuring height of available bone.

Title: The Esthetic Outcome and the Infiltration Capacity of Three Resin Composite Sealers Compared to ICON (DMG, America). Objective: The aim of these studies, including a randomized control in-vitro study and a survey study was to answer the following question: In treating initial caries lesions, is the esthetic outcome and the infiltration capacity of the three resin composite sealers; BisCover LV (Bisco Dental), Optiguard (Kerr), PermaSeal (Ultradent) similar to that of the gold standard ICON (DMG, America) resin infiltrant. Methods: A sample of 75 extracted human permanent molars were painted with an acid resistant nail varnish (Revlon, USA) to protect the tooth surface from demineralization leaving only two panels of 1x7 mm of exposed enamel on the buccal and the lingual surfaces of each tooth to be demineralized. Samples were immersed in an acidic gel (500g of Fisher G-8 Gelatin, 275 Bloom, 0.1% thymol, lactic acid, pH 4.30) for a period of 3 months to create artificial initial caries lesions. Seventy-five specimens were randomly assigned to 5 groups: I: ICON (DMG, America), B: BisCover LV (Bisco Dental), O: Optiguard (Kerr), P: PermaSeal (Ultradent) and C: control group. Specimens were hemi sectioned yielding two halves, each with a panel of 1x7 mm of initial caries lesion. One side was used to assess the esthetic following the caries lesion resin infiltration with ICON, BisCover LV, Optiguard and PermaSeal applied according to ICON manufacturer instructions. The control group (C) did not receive any treatment and was only included in the esthetic part of this study. Preoperative and postoperative photographs were taken. Two sets of photographs were taken for the control group. The preoperative, postoperative and control group photographs were installed in a PowerPoint presentation and placed side by side on a black background. A total of 17 operative faculties and residents at the department of operative dentistry at the University of Iowa (UI) participated in the survey. The esthetic improvement was assessed based on a 100-mm visual analogue scale (VAS). A value between 0 and 20 indicated slight esthetic improvement. A value between 20 and 40 indicated mild esthetic improvement. A value between 40 and 60 indicated moderate esthetic improvement. A value between 60 and 80 indicated high esthetic improvement. A value between 80 and 100 indicated outstanding esthetic improvement. A value of 100 indicated full esthetic recovery. Each subject was asked to look at the preoperative and postoperative photographs of a specimen in each slide and place a line on the respective VAS according to her/his opinion of esthetic improvement. The survey was conducted twice in two different sessions to evaluate the inter-rater and intra-rater reliability. For lesions on the opposite side, the resins: ICON, BisCover™LV, Optiguard and PermaSeal were applied according to the indirect dual fluorescence technique protocol using the red fluorophore rhodamine B isothiocyanate (RITC 0.1%; Sigma Aldrich, Steinheim, Germany) and the green sodium fluorescein (NaFl; Sigma Aldrich). Specimens were sectioned in a mesio-distal direction yielding thin sections of 200 μm and were visualized under the Confocal Laser Scanning Microscope (CLSM, Leica Microsystems, Buffalo Grove, IL.) to assess the infiltration depth percentage (ID%) and the infiltration area percentage (IA%) following the application of the different resins. Statistical analysis: The effect of treatment type on ID% and IA% was evaluated using the one-way ANOVA. The effect of treatment type on esthetic improvement measures represented by VAS scores was evaluated using the non-parametric analogue of the one-way ANOVA; Kruskal-Wallis test. All pairwise comparisons were performed using the Tukey method with an overall 0.05 level of significance. Spearman rank correlations were used to assess the relationship between esthetic improvement measures and infiltration measures. Validity of assumptions related to normality and variance homogeneity were assessed using the Shapiro-Wilk and Brown-Forsythe tests, respectively. The intra-class correlation and associated 95% confidence interval reflecting the reproducibility of the mean VAS scores and the reliability among the evaluators were obtained using the method of Shrout and Fleiss. The Wilcoxon Signed Rank procedure was used to evaluate differences between sessions for individual evaluators. The paired student’s t-test was used to detect any systematic differences between the mean VAS scores at session 1 and 2. Bonferroni adjustment for multiple testing was made for the 17 tests associated with individual raters, using an overall 0.05 level of significance. Results: the mean IA% values were significantly higher in the ICON group compared to the other three treatment groups. Optibond and Permaseal groups resulted in intermediate values that did not differ significantly from each other. Biscover group yielded the lowest mean values and were significantly lower than that of the other three treatment groups. The results of the ID% values were consistent with the results of the IA% values. the mean ID% values were significantly higher in the ICON group compared to the other three treatment groups. Optibond and Permaseal groups resulted in intermediate values that did not differ significantly from each other. Biscover group yielded the lowest mean values and were significantly lower than that of the other three treatment groups. The distribution of esthetic improvement outcomes represented by the average VAS scores for session 1 (AVGVAS1), average VAS scores for session 2 (AVGVAS2), and the combined average VAS scores (AVERAGED_VAS) for each sample obtained from the two sessions were all significantly lower in the control group than in the other four treatment groups. Biscover yielded intermediate average VAS values. ICON, Optiguard and Permaseal yielded significantly greater average VAS values than both the control and Biscover groups and were not significantly different from each other. According to the Spearman rank correlations which was used to assess the relationships between the esthetic improvement measures; AVGVAS1, AVGVAS2 and AVERAGED_VAS for each sample and the two measures of infiltration; the IA% and the ID%, all results were highly significant (p<0.0001) and indicative of a moderately large positive correlation between each of the infiltration measures and the three esthetic improvement measures. The Spearman coefficients for the six relationships evaluated were quite similar, ranging from about 0.523 to 0.548. Conclusion: The resin composite sealers BisCover LV, Optiguard and Permaseal can infiltrate artificial initial caries lesions. The esthetic outcome of artificial initial caries lesion following resin infiltration with Optiguard and Permaseal was similar to ICON and thus might be adequately used in caries resin infiltration. BisCover LV showed the least esthetic improvement and thus might not be indicated for the esthetic management of initial caries lesions but might be used for caries prevention purposes. The esthetic improvement is correlated to the resin infiltration depth to a certain extent after which the esthetic outcome will not be visually impacted.

Objectives: This study evaluated the effects of extended acid etching on microtensile bond strength (µTBS) of a etch and rinse adhesive system to sound vital dentin. Etching times of 5, 20 and 80 seconds was used to evaluate the µTBS on vital dentin with resin bonded composite [RBC] restoration (Esthet-XTM) which used a two step etch and rinse adhesive system(Prime Bond NTTM) for bonding. Methods: 26 premolars which were going to be extracted for orthodontic treatment were used for this experiment. The teeth were randomly divided into 3 groups based on the etch times and restored with RBC using two step adhesive and extracted in `Guarulhos University' Brazil. After extraction, these teeth were sectioned ( Microtome) in such a way to obtain 2 testing beams of 2mm diameter from each tooth were obtained which were trimmed (CNC specimen former, University of Iowa, IA, USA) to a dumb bell shape and tested for the microtensile bond strength in University of Iowa. Out of 26 teeth, 46 beams were obtained. For statistical analysis, One-way ANOVA with post-hoc Tukey-Kramer's test was used to determine whether there were significant differences in micro-tensile bond strength among three etching times under each condition. All tests had a 0.05 level of statistical significance. SAS for Windows (v9.1, SAS Institute Inc, Cary, NC, USA) was used for the data analysis. Fracture mode was analyzed using scanning electron microscopy. Results: Bond strengths in 20 seconds and 5 seconds groups were significantly greater than that observed in 80 seconds group, while there was no significant difference between 20 and 5 etching times.SEM showed majority of the failure was adhesive/ joint failure. Significance: The results in this In-vivo study are consistent with other in-vitro studies and thus bring an insight on the importance of duration of phosphoric acid application on dentin and extended etch times could compromise the bond strength of the restorations.

No description available.

Objective: To assess the effects of ceramic opacity and thickness on delivered radiant exposure and degree of conversion and microhardness of the light-cured resin cement. Materials and Methods: IPS e-Max ceramic discs (Ivoclar Vivadent) were fabricated in 3 thicknesses (0.5, 1.0, and 1.5mm) and 4 opacities (HT, LT, MO, HO) (n=3/per group). Light-cured resin cement (Variolink Veneer Luting Cement - shade MVO, Ivoclar Vivadent) 50µm thick was cured through these ceramics disks using a quartz tungsten halogen curing light unit (Optilux 501, Kerr) with its radiant exposure measured by MARC from a fixed distance (1.5mm). Knoop microhardness was used to evaluate the bottom degree of cure and was correlated with the radiant exposure deliverd. Descriptive statistics were conducted. One- and two-way ANOVA with post-hoc Tukey's HSD test, Pearson correlation test, the simple linear regression analysis were used for the statistical analyses (alpha=0.05). Results: Significant interaction was found between ceramic thickness and opacity on radiant exposure (p=0.0078). Subsequent analyses demonstrated that there was a significant simple effect for opacity and for thickness on radiant exposure under different conditions of thickness and opacity. A significant relationship was found between resin cement microhardness and radiant exposure (p=0.0001) below 4.5 J/cm2. Moreover, the Pearson correlation coefficient of 0.93 indicated a strong correlation between the two variables below 4.5 J/cm2 of radiant exposure delivered. Conclusion: Ceramic opacity and thickness affect the polymerization of light-cured resin cements and need to be considered and compensated for when bonding indirect restorations. Based upon the findings of this preliminary study, the final study is ongoing.

No description available.

Master of Dental Surgery / The lack of adaptation between restorative materials and tooth structure has for many years been a major problem in Dentistry. Studies during this time have emphasized that the margins of restorations are not fixed, inert and impenetrable borders, but dynamic microcrevices which contain a busy traffic of ions and molecules (Going, 1972). The microleakage which results, has been defined as “the clinically undetectable passage of bacteria, fluids and molecules or ions between a cavity wall and the restorative materials applied to it” (Kidd, 1976, b). Microleakage has been implicated in a variety of clinical conditions, including recurrent caries, tooth discolouration, hyper-sensitivity, pulp pathology and hastened breakdown of restorative materials (Kidd, 1976, a and b; Torney et al, 1977). Buonocore (1955) was probably the first to bond resins to tooth structure, etched by the application of phosphoric acid to enamel surfaces. It was found that etching the enamel converted a previously hydrophobic, low energy surface to a more wettable high energy state possessing an increased surface area with numerous retentive sites for resin tag formation. Over the years, the acid-etch technique has been used in a number of dental procedures including fissure sealing, the repair of fractured incisal edges, the repair of hypoplastic and abraded areas, the placement of orthodontic brackets and the splinting of teeth. In recent years, studies have evaluated the ability of the acid-etch technique to improve both the adaptation and retention of composite resins to tooth structure and the marginal seal around composite restorations. However, much of the research examining adaptation of composite resins to tooth enamel has been limited to the study of the enamel tooth surface rather than the enamel of the cavity wall. In addition, previous studies have paid little attention to the effects, on the microleakage, of different etching times and different sizes of the inorganic filler particles and to the influence of aging the restorations on the microleakage. The review of the literature also indicated some controversy concerning the use and effectiveness of low viscosity resins. Since the early 1970’s acid-etching of the enamel has been used increasingly in the placement of composite resin restorations, to provide retention and to minimize marginal microleakage. It was the purpose of this investigation to examine the etched enamel cavity wall, to compare the ability of composite resins, of different particle size and viscosity, to adapt to this cavity wall, and to study the influence, in vitro, of these and other factors, on the microleakage occurring at the margins of restoration.