Acknowledgements - UCSF School of Dentistry - University of ...

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 of the culture was analyzed for collagenase-like proteinases using a quenched fluorescent
substrate. The secreted proteins of LB in the supernatant were further extracted by precipitation and analyzed for their zymographic
profile. 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 of LB culture, not in the bacterial pellet. The existence
of 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 of LB may play an
important role in dentin caries progression.
#62 Title: Alternative practice patterns of dental hygienists
C WIDES (1), E MERTZ, E (1), J SPETZ (2)
(1) UCSF School of Dentistry (2) UCSF IHPS
Objectives: The recruitment and retention of 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, professional, and structural predictors of dental hygiene practice in NTS.
Methods: A stratified random sample survey of 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
professional preferences and opinions. Characteristics of hygienists reporting paid employment in NTS were examined to find
predictors of 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 of health care professionals (OR=3.00), and holding an alternative practice license (OR=4.20).
Gaining job satisfaction from advancement and professional 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 of 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 of Dental & Craniofacial Research Award # P30DE020752.
#63 Title: Epidemiological Analysis of 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 of Biopharmaceutical Sciences, † Department of Orofacial Sciences Departments of Medicine, Ɣ Departments of
Epidemiology & Biostatistics, University of California San Francisco, San Francisco, CA; ‡ California Pacific Medical Center
Research Institute, San Francisco, CA; ‖ Department of Dental Public Health, University of Pittsburgh, Pittsburgh, PA
Introduction: The development of periodontal diseases is influenced by many risk factors; however, the relative importance of tese
risk factors is unclear due to large differences in study design of previous studies.
Objectives: To better understand the relative importance of risk factors for periodontal diseases, we have estimated and compared
the risk of 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 of ~2,250 individuals with periodontal exams, and characterization of dental habits,
education, smoking habits, fasting glucose, sex, age, vitamin D, BMI, and alcohol consumption habits. We estimated the percent
variance of 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% of the variance of periodontal
outcomes). The largest modifiable risk factors were dental habits, such as plaque index, frequency of flossing, and frequency of
dental visits (up to 20% of the variance). Other well established risk factors, smoking and education, were found to explain up to
2.5% of the variance. Potential risk factors, alcohol consumption and low vitamin D, were found to explain up to 1% of the variance,
while fasting glucose and BMI were found to explain less than 0.5% of the variance of periodontal outcomes. Overall, our study
indicates the need for more precise measures of periodontal diseases, as the large portion of variance of 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.
School of Dentistry Research and Clinical Excellence Day 2011 Program 27