Materials and Methods: LB (ATCC7469) was cultured on selective media plates and sub-cultured in BHI anaerobically for 48 hours. The supernatant or cell pellet <strong>of</strong> the culture was analyzed for collagenase-like proteinases using a quenched fluorescent substrate. The secreted proteins <strong>of</strong> LB in the supernatant were further extracted by precipitation and analyzed for their zymographic pr<strong>of</strong>ile. The proteinases identified were further characterized for pH tolerance, substrate specificity and susceptibility to metal ions, EDTA and PMSF. Results: The active collagenase-like proteinase was detected in supernatant <strong>of</strong> LB culture, not in the bacterial pellet. The existence <strong>of</strong> proteinases was confirmed by zymography containing collagen substrate. A major proteinase-active band at 50 kDa was noted, co-existing with multiple minor active bands at smaller sizes. The active proteinase is specific to collagen and gelatin substrates but not casein. The enzymes tolerate pH from 4 to 8. The proteinase activities were completely inhibited by EDTA but not by serine proteinase inhibitor PMSF. Conclusions: LB secretes proteinases with collagenase activity that belongs to metalloproteinase family. LB proteinases tolerate a wide pH range including low-pH (4) and are specific to collagen but not casein. The collagenase-like activity <strong>of</strong> LB may play an important role in dentin caries progression. #62 Title: Alternative practice patterns <strong>of</strong> dental hygienists C WIDES (1), E MERTZ, E (1), J SPETZ (2) (1) <strong>UCSF</strong> <strong>School</strong> <strong>of</strong> <strong>Dentistry</strong> (2) <strong>UCSF</strong> IHPS Objectives: The recruitment and retention <strong>of</strong> dental health care practitioners to in underserved areas improves access to care and reduces health disparities. In California, Registered Dental Hygienists (RDH) may be employed in non-traditional settings (NTS) or they may gain additional licensure to practice independently as Registered Dental Hygienists in Alternative Practice (RDHAP). This study explores the personal, pr<strong>of</strong>essional, and structural predictors <strong>of</strong> dental hygiene practice in NTS. Methods: A stratified random sample survey <strong>of</strong> licensed dental hygienists in California was conducted from October 2005 to January 2006, with a 73% response rate. The survey obtained data on demographics, education, practice characteristics and pr<strong>of</strong>essional preferences and opinions. Characteristics <strong>of</strong> hygienists reporting paid employment in NTS were examined to find predictors <strong>of</strong> non-traditional practice. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed using logistic regression. Conclusions: Paid employment in NTS for active, clinical dental hygienists (n=1,725) was positively significantly associated with being unmarried (OR=2.90), gaining job satisfaction from autonomy (OR=2.12), a preference for either working in underserved areas (OR=2.00) or with other types <strong>of</strong> health care pr<strong>of</strong>essionals (OR=3.00), and holding an alternative practice license (OR=4.20). Gaining job satisfaction from advancement and pr<strong>of</strong>essional growth within dental hygiene (OR=0.48) was negatively associated with paid employment in NTS. Dental hygienists working in NTS have distinctive personal characteristics and motivations. The dental safety net is relatively small sector <strong>of</strong> the delivery system that struggles with recruiting dental providers. Yet our study showed that hygienists are interested in this work, and even willing to gain additional education and licensure to practice in this sector. Primary Funding Source: Funding provided by National Institute <strong>of</strong> Dental & Crani<strong>of</strong>acial Research Award # P30DE020752. #63 Title: Epidemiological Analysis <strong>of</strong> the Risk Factors for Periodontal Diseases LM REYNOLDS*, MI RYDER † , DS EVANS ‡ , GJ TRANAH ‡ , RJ WEYANT ‖ , AB NEWMAN ‖ , KR PHIPPS, W-C HSUEH Ɣ *Department <strong>of</strong> Biopharmaceutical Sciences, † Department <strong>of</strong> Or<strong>of</strong>acial Sciences Departments <strong>of</strong> Medicine, Ɣ Departments <strong>of</strong> Epidemiology & Biostatistics, <strong>University</strong> <strong>of</strong> California San Francisco, San Francisco, CA; ‡ California Pacific Medical Center Research Institute, San Francisco, CA; ‖ Department <strong>of</strong> Dental Public Health, <strong>University</strong> <strong>of</strong> Pittsburgh, Pittsburgh, PA Introduction: The development <strong>of</strong> periodontal diseases is influenced by many risk factors; however, the relative importance <strong>of</strong> tese risk factors is unclear due to large differences in study design <strong>of</strong> previous studies. Objectives: To better understand the relative importance <strong>of</strong> risk factors for periodontal diseases, we have estimated and compared the risk <strong>of</strong> many known and potential risk factors in three large populations. This information may be useful to guide future epidemiological investigations, as well as to guide public health education strategies to prevent periodontal diseases. Methods: Our study populations consist <strong>of</strong> ~2,250 individuals with periodontal exams, and characterization <strong>of</strong> dental habits, education, smoking habits, fasting glucose, sex, age, vitamin D, BMI, and alcohol consumption habits. We estimated the percent variance <strong>of</strong> four periodontal disease outcomes explained by each risk factor. Periodontal disease outcomes included: mean plaque index, % bleeding on probing, extent pocket depth ≥ 5mm, and extent attachment loss ≥ 3mm. Results: Periodontal examiner accounted for more variance than any risk factor (up to 25% <strong>of</strong> the variance <strong>of</strong> periodontal outcomes). The largest modifiable risk factors were dental habits, such as plaque index, frequency <strong>of</strong> flossing, and frequency <strong>of</strong> dental visits (up to 20% <strong>of</strong> the variance). Other well established risk factors, smoking and education, were found to explain up to 2.5% <strong>of</strong> the variance. Potential risk factors, alcohol consumption and low vitamin D, were found to explain up to 1% <strong>of</strong> the variance, while fasting glucose and BMI were found to explain less than 0.5% <strong>of</strong> the variance <strong>of</strong> periodontal outcomes. Overall, our study indicates the need for more precise measures <strong>of</strong> periodontal diseases, as the large portion <strong>of</strong> variance <strong>of</strong> periodontal outcomes explained by examiner may overshadow the actual risk associated with other risk factors. Support: The following institutes provided support: NIA, NIH, NIAMS, and NIDCR. <strong>School</strong> <strong>of</strong> <strong>Dentistry</strong> Research and Clinical Excellence Day 2011 Program 27
Research and Clinical Excellence Day Special Thanks to the following faculty Jeff Bush, PhD Lisa Chung, DDS, MPH Richard Jordan, DDS, PhD, FRCPath Peter Loomer, BSc, DDS, PhD, Chair Dorothy Perry, RDH, PhD Arun Sharma, DDS Judges Gurrinder Atwal, DDS, MS Troy Daniels, DDS Alice Goodwin, DDS Jeremy Horst, DDS, PhD Ann Lazar, PhD, MS Michael McMaster, PhD Vagan Mushegyan Peter Rechmann, PhD Ram Vaderhobli, DDS, MS Piri Veluppillai, BDS, MS <strong>Acknowledgements</strong> Research and Clinical Excellence Day Support Staff Roger Mraz, Coordinator David Hand, Coordinator Additional Thanks To Arvin Ahmadieh Osvaldo Amezcua Tyler Block Jonathan Collins Rory Devine Joseph Eliason Tami Lam Padric McCaig Erik Eduardo Meza Thomas Nguyen Carol Pierotti Sarah Steer Joshua Talley Ralph Thomas John C. Greene Society Jeremy Lin, President Robert C. Lee, Vice President The Pre-Dental Society <strong>of</strong> Berkeley <strong>School</strong> <strong>of</strong> <strong>Dentistry</strong> Research and Clinical Excellence Day 2011 Program 28
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