Introduction: The Rho family of small GTPases, including Rac1 and Rac2, are key regulators of osteoclast differentiation and function; however, little is known about their roles in bone quality and aging. Methods: Male four and nine month old mice (n=10) with Rac1, Rac2 or both (DKO) isoforms deleted in osteoclast precursors were assessed using dual energy x-ray absorptiometry (DXA), scanning electron microscopy (SEM), micro computed tomography (microCT), compression, torsion and three-point bending testing, back scattered electron microscopy (BSE), Goldner’s trichrome and TRAP staining. Results: All Rac null mice demonstrated decreased cortical structural properties and improved trabecular architecture. With age, Rac null mice demonstrated the ability to attenuate age-related bone loss. Conclusions: Using an in vivo model with Rac1, Rac2 or both Rac isoforms deleted in osteoclasts, our findings demonstrate the deletion of Rac1 and Rac2 compromised cortical bone while improving trabecular bone properties and attenuated age-related bone loss.

Introduction: The Rho family of small GTPases, including Rac1 and Rac2, are key regulators of osteoclast differentiation and function; however, little is known about their roles in bone quality and aging. Methods: Male four and nine month old mice (n=10) with Rac1, Rac2 or both (DKO) isoforms deleted in osteoclast precursors were assessed using dual energy x-ray absorptiometry (DXA), scanning electron microscopy (SEM), micro computed tomography (microCT), compression, torsion and three-point bending testing, back scattered electron microscopy (BSE), Goldner’s trichrome and TRAP staining. Results: All Rac null mice demonstrated decreased cortical structural properties and improved trabecular architecture. With age, Rac null mice demonstrated the ability to attenuate age-related bone loss. Conclusions: Using an in vivo model with Rac1, Rac2 or both Rac isoforms deleted in osteoclasts, our findings demonstrate the deletion of Rac1 and Rac2 compromised cortical bone while improving trabecular bone properties and attenuated age-related bone loss.

Background: In this study, we enhanced a diagnostic questionnaire which had been previously developed to measure stress and social support. Methods: 101 patients with chronic periodontitis and 50 healthy control subjects completed our questionnaire package after which we analyzed the data for trends and associations. Results: Our enhanced questionnaire provided a valid and reliable measure of stress and social support in patients with chronic periodontitis. Conclusion: Our enhanced questionnaire provided both a valid and a reliable measure of stress and social support in patients with chronic periodontitis however requires further refinement to predict periodontal disease experience and severity.

Background: In this study, we enhanced a diagnostic questionnaire which had been previously developed to measure stress and social support. Methods: 101 patients with chronic periodontitis and 50 healthy control subjects completed our questionnaire package after which we analyzed the data for trends and associations. Results: Our enhanced questionnaire provided a valid and reliable measure of stress and social support in patients with chronic periodontitis. Conclusion: Our enhanced questionnaire provided both a valid and a reliable measure of stress and social support in patients with chronic periodontitis however requires further refinement to predict periodontal disease experience and severity.

The purpose of the study is to describe the impact of oral health-related quality of life (OHRQoL) on the lives of pre-seniors and seniors living in Nova Scotia, Canada. This cross-sectional study involved 1461 participants, grouped by age (pre-seniors [45-64] and seniors [65+]) and residential status (long-term care facility [LTC] or community). OHRQoL was measured using the 14-item Oral Health Impact Profile questionnaire. Approximately one in four pre-seniors and seniors reported at least one OHRQoL impact ‘fairly/very often’. Of those residing in the community, pre-seniors (28.8%) reported significantly more impacts than seniors (22.0%). Logistic regression revealed that for the community dwelling sample, those who were dissatisfied with their teeth or dentures were 5.16 times more likely to report an impact ‘fairly/very often’, which was the strongest indicator. Among the LTC sample, those who have poor perceived mouth health were 9.87 times more likely to report an impact.

The purpose of the study is to describe the impact of oral health-related quality of life (OHRQoL) on the lives of pre-seniors and seniors living in Nova Scotia, Canada. This cross-sectional study involved 1461 participants, grouped by age (pre-seniors [45-64] and seniors [65+]) and residential status (long-term care facility [LTC] or community). OHRQoL was measured using the 14-item Oral Health Impact Profile questionnaire. Approximately one in four pre-seniors and seniors reported at least one OHRQoL impact ‘fairly/very often’. Of those residing in the community, pre-seniors (28.8%) reported significantly more impacts than seniors (22.0%). Logistic regression revealed that for the community dwelling sample, those who were dissatisfied with their teeth or dentures were 5.16 times more likely to report an impact ‘fairly/very often’, which was the strongest indicator. Among the LTC sample, those who have poor perceived mouth health were 9.87 times more likely to report an impact.

Master of Science / Department of Industrial & Manufacturing Systems Engineering / Malgorzata J. Rys / The current state of the dental industry shows an increasing number of dentists and dental hygienists who are reducing hours and retiring early due to the injuries sustained while working. These injuries, or cumulative trauma disorders, can be reduced by applying ergonomics in dental tool design. The goal of ergonomics is to reduce current injuries but also prevent future ones. In addition, population demographics have shown an increasing trend in female dentists. With a shift from the male dominated field, design for different anthropometric measurements needs to be investigated. In order to pinpoint sources of pain, a survey was designed and distributed to dentists in Kansas, Missouri, and Texas. Even with a small sample size (n=24), results confirmed past studies in the dental industry of pain originating in the neck, shoulder, lower back, and wrist/hand region. The reasons stemmed from the repetitive motions and forces applied during dental procedures. Responses also found that ergonomic principles need to be applied to the handle and grip portion of dental scaler design. Dental scaling is the procedure to remove deposits on teeth, such as plaque and calculus, most commonly performed by dental hygienists. First, the history of dental tools, angulation, tool weight, and materials currently utilized were researched before looking into specific design factors for modification. Currently, the handle grip area on all dental tools range in size, but a 10 mm grip has been proven to be optimal. The optimal tool weight has yet to be determined as 15 grams is the lowest weight to be tested. Most tools are made of stainless steel and resins, which are not compressible. An experiment was designed to test a new dental scaler (A) made of a titanium rod with added compressibility in the precision grip area. The aim was to help reduce pressure on the fingers and hand muscles and increase comfort during scaling. The experiment utilized a Hu-Friedy sickle scaler (B) and a Practicon Montana Jack scaler (C) as controls to show two design spectrums, weight and material. The subjects (n=23) were taught the basics of scaling and required to scale using a typodont. The change in grip strength (Δ GS), pinch strength (Δ PS), and steadiness of the subjects hand were tested. An absolute and relative rating technique was utilized pinpointing that the new dental scaler was preferred with the eigenvector (A=0.8615, B=0.1279, C=0.0106). Statistical analysis confirmed this tool preference while also finding the interaction of gender and tool and Δ GS Tool A versus Tool B for males to be significant.

Objective: To assess biofilm proliferation within the sealer-dentin interfaces of methacrylate resin-based sealers, self-etch (SE) and total-etch (TE), and an epoxy resin-based sealer (EP). Methods: Standardized human root specimens were filled with the test materials and were aged for 1 week, 1, 3 or 6 months in saline (n=3/group). Monoclonal biofilms of Enterococcus faecalis were grown on the specimens for 7 days in continuous media reactor. The extent of biofilm proliferation of E. faecalis within the sealer-dentin interface for each material at each incubation period was assessed using fluorescence microscopy of dihydroethidium-stained specimens. Results: TE had less biofilm proliferation than EP and SE (p<0.01). Deeper biofilm proliferation was detected in SE and EP specimens aged for 1 and 3 months than those aged for 1 week or 6 months (p<0.05). Conclusion: Self-etch and epoxy resin-based sealers were more susceptible to interfacial biofilm proliferation than total-etch system at shorter incubation periods.

Objective: To assess biofilm proliferation within the sealer-dentin interfaces of methacrylate resin-based sealers, self-etch (SE) and total-etch (TE), and an epoxy resin-based sealer (EP). Methods: Standardized human root specimens were filled with the test materials and were aged for 1 week, 1, 3 or 6 months in saline (n=3/group). Monoclonal biofilms of Enterococcus faecalis were grown on the specimens for 7 days in continuous media reactor. The extent of biofilm proliferation of E. faecalis within the sealer-dentin interface for each material at each incubation period was assessed using fluorescence microscopy of dihydroethidium-stained specimens. Results: TE had less biofilm proliferation than EP and SE (p<0.01). Deeper biofilm proliferation was detected in SE and EP specimens aged for 1 and 3 months than those aged for 1 week or 6 months (p<0.05). Conclusion: Self-etch and epoxy resin-based sealers were more susceptible to interfacial biofilm proliferation than total-etch system at shorter incubation periods.