Efficiency of split-mouth designs

The purpose of this paper is (1) to investigate the similarity of the amount, distribution, and, severity of periodontal disease of the within-patient experimental units, (2) to estimate the relative efficiencies of split-mouth designs when compared to whole-mouth designs, and (3) to discuss how stratification on initial pocket depth can result in large differences in the power of the test-statistics in the different disease categories. Periodontal disease characteristics are not always homogeneously distributed over the within-patient experimental units and this heterogeneity can reduce the efficiency of split-mouth designs. In particular, if analyses are stratified on initial pocket depth, sites with an initial probing depth deeper than 6 mm may be small in number and asymmetrically distributed when compared to sites with an initial probing depth less than 6 mm. This may result in large differences of the power of the test statistics among the different disease categories and should lead to a careful interpretation of the statistical significance tests. When disease characteristics are symmetrically distributed over the within-patient experimental units and a sufficient number of sites is present per experimental unit, the split-mouth design can provide moderate to large gains in relative efficiency. In the absence of a symmetric disease distribution, whole-mouth clinical trials may be preferable.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71402/1/j.1365-2710.1992.tb01204.x.pd

Initial Program Evaluation of an Ignatian Leadership Development Program: The Haddix Dean\u27s Fellows Program

This chapter shares assessment results from a 4-year undergraduate Ignatian Leadership program. The Dean’s Fellows program consists of several curricular and co-curricular elements, including cohort-based seminars, a common summer read, an annual retreat, social and cultural activities, and a concluding leadership immersion experience. Learning formats throughout the four years included lectures, small and large group discussions, and workshops. For the immersion experience, the Dean’s Fellows participated in preparatory lectures that included information on cultural intelligence, anticipatory reflection, Ignatian Leadership, and discernment, as well as topical information. In order to ensure and improve program outcomes, assessment processes were developed, and data included both quantitative and qualitative measures. Rothausen (2017) provided a theoretical framework that aligns secular leadership development models with Ignatian Leadership. Unfortunately, validated measures of Ignatian Leadership do not exist to date. To address this limitation, we utilized instruments drawn from the field of leadership studies that logically approximate values and practices found within the Ignatian Leadership paradigm. We also conducted a focus group with students completing the 4-year experience and collected pre- and post- program reflection papers. Results from both quantitative and qualitative approaches along with both practical and pedagogical suggestions are offered for those seeking to build a similar program

Reduction of Dental Decay in Rampant Caries Individuals Following Short-Term Kanamycin Treatment

A week of kanamycin gel treatment before and after the placement of dental restorations, compared to a placebo gel treatment, significantly reduced the levels of cultivable bacteria, S mutans and S sanguis, in the plaque samples collected immediately after the completion of the gel treatments, and was associated with a 46% reduction in new carious surfaces in the 14- to 37-month period following the gel treatment.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68298/2/10.1177_00220345770560031101.pd

(Not so) dangerous liaisons: A framework for evaluating collaborative research projects

Cite as: Oztop, P., Loesche, F., Maranan, D. S., Francis, K. B., Tyagi, V., & Torre, I. (2017). (Not so) dangerous liaisons: A framework for evaluating collaborative research projects [Special Issue]. AVANT, 8, 167–179© 2017, Centre for Philosophical Research. With advances in research environments and the accompanying increase in the complexity of research projects, the range of skills required to carry out research calls for an increase in interdisciplinary and collaborative work. CogNovo, a doctoral training program for 25 PhD students, provided a unique opportunity to observe and analyze collaborative processes. We propose a process-oriented framework for understanding research collaborations along two dimensions: interpersonal and project-related. To illustrate the utility of this process-oriented framework, we apply the framework matrix to several collaborations that emerged within the CogNovo program. The framework that we introduce has several advantages over existing metrics. Firstly, we offer a process-oriented-as opposed to product-oriented-evaluation of interdisciplinary and collaborative endeavors. Secondly, we propose a means of assessment that preserves the distinctive profile (or "fingerprint") of a given collaborative project, thus capturing the uniqueness of each project and its environment

The benzoylarginine peptidase from Treponema denticola (strain ASLM), a human oral spirochaete: evidence for active-site carboxyl groups

The benzoylarginine peptidase of Treponema denticola (strain ASLM; a human oral spirochaete) was progressively and irreversibly inactivated by 1-(ethoxycarbonyl)-2-ethoxy-1, 2-dihydroquinoline, a carboxyl-group reagent. At acidic pH values, reaction of one mole of the modifier per active site of the enzyme resulted in total inactivation of the enzyme. Assuming that this modifier is a specific carboxyl reagent, the data suggest that the inactivation of the T. denticola benzoylarginine peptidase was caused by the modification of one carboxyl group located close to the active site of the enzyme. Results obtained with Woodward's reagent K ( N -ethyl-5-phenylisoxazolium 3’-sulphonate) supported these findings. Carbethoxylation with diethylpyrocarbonate effectively inactivated the enzyme, and addition of hydroxylamine at pH 7.0 restored the activity almost totally, suggesting that the pyrocarbonate had reacted with tyrosyl or histidyl residues.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73886/1/j.1365-2958.1990.tb00721.x.pd

Recovery of Streptococcus mutans and Streptococcus sanguis from a dental explorer after clinical examination of single human teeth

Certain aspects of the bacterial flora adhering to a dental explorer following a tactile diagnostic examination of a single tooth were investigated. Plaque present on the explorer was dislodged, and suspended into a reduced transport fluid by sonification. After serial dilution, suitable aliquots were placed on a high sucrose-containing medium, and on a mannitol medium. Colonies resembling Streptococcus mutans and Streptococcus sanguis were enumerated on these media. The explorer removed approximately 3-7 x 106 bacteria from a single tooth. Streptococcus mutans accounted for 17 per cent of the isolates from carious teeth and for 1.6 per cent of the isolates found on noncarious teeth. This difference was significant at the p Strep. sanguis were significantly higher in material removed from noncarious teeth than in plaque removed from the carious teeth.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33912/1/0000177.pd

Bacterial and Salivary Biomarkers Predict the Gingival Inflammatory Profile

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141936/1/jper0632-sup-0001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141936/2/jper0632-sup-0002.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141936/3/jper0079.pd

Xylitol gummy bear snacks: a school-based randomized clinical trial

Background: Habitual consumption of xylitol reduces mutans streptococci (MS) levels but the effect on Lactobacillus spp. is less clear. Reduction is dependent on daily dose and frequency of consumption. For xylitol to be successfully used in prevention programs to reduce MS and prevent caries, effective xylitol delivery methods must be identified. This study examines the response of MS, specifically S. mutans/sobrinus and Lactobacillus spp., levels to xylitol delivered via gummy bears at optimal exposures. Methods: Children, first to fifth grade (n = 154), from two elementary schools in rural Washington State, USA, were randomized to xylitol 15.6 g/day (X16, n = 53) or 11.7 g/day (X12, n = 49), or maltitol 44.7 g/ day (M45, n = 52). Gummy bear snacks were pre-packaged in unit-doses, labeled with ID numbers, and distributed three times/day during school hours. No snacks were sent home. Plaque was sampled at baseline and six weeks and cultured on modified Mitis Salivarius agar for S. mutans/sobrinus and Rogosa SL agar for Lactobacillus spp. enumeration. Results: There were no differences in S. mutans/sobrinus and Lactobacillus spp. levels in plaque between the groups at baseline. At six weeks, log10 S. mutans/sobrinus levels showed significant reductions for all groups (p = 0.0001): X16 = 1.13 (SD = 1.65); X12 = 0.89 (SD = 1.11); M45 = 0.91 (SD = 1.46). Reductions were not statistically different between groups. Results for Lactobacillus spp. were mixed. Group X16 and M45 showed 0.31 (SD = 2.35), and 0.52 (SD = 2.41) log10 reductions, respectively, while X12 showed a 0.11 (SD = 2.26) log10 increase. These changes were not significant. Post-study discussions with school staff indicated that it is feasible to implement an in-classroom gummy bear snack program. Parents are accepting and children willing to consume gummy bear snacks daily. Conclusion: Reductions in S. mutans/sobrinus levels were observed after six weeks of gummy bear snack consumption containing xylitol at 11.7 or 15.6 g/day or maltitol at 44.7 g/day divided in three exposures. Lactobacillus spp. levels were essentially unchanged in all groups. These results suggest that a xylitol gummy bear snack may be an alternative to xylitol chewing gum for dental caries prevention. Positive results with high dose maltitol limit the validity of xylitol findings. A larger clinical trial is needed to confirm the xylitol results. Trial registration: [ISRCTN63160504].Supported by Grant No. U54DE14254 from the National Institute of Dental and Craniofacial Research, and Grant No. 90YD0188 from the Office of Head Start

Dental plaque as a biofilm and a microbial community – implications for health and disease

Dental plaque is a structurally- and functionally-organized biofilm. Plaque forms in an ordered way and has a diverse microbial composition that, in health, remains relatively stable over time (microbial homeostasis). The predominant species from diseased sites are different from those found in healthy sites, although the putative pathogens can often be detected in low numbers at normal sites. In dental caries, there is a shift toward community dominance by acidogenic and acid-tolerating species such as mutans streptococci and lactobacilli, although other species with relevant traits may be involved. Strategies to control caries could include inhibition of biofilm development (e.g. prevention of attachment of cariogenic bacteria, manipulation of cell signaling mechanisms, delivery of effective antimicrobials, etc.), or enhancement of the host defenses. Additionally, these more conventional approaches could be augmented by interference with the factors that enable the cariogenic bacteria to escape from the normal homeostatic mechanisms that restrict their growth in plaque and out compete the organisms associated with health. Evidence suggests that regular conditions of low pH in plaque select for mutans streptococci and lactobacilli. Therefore, the suppression of sugar catabolism and acid production by the use of metabolic inhibitors and non-fermentable artificial sweeteners in snacks, or the stimulation of saliva flow, could assist in the maintenance of homeostasis in plaque. Arguments will be presented that an appreciation of ecological principles will enable a more holistic approach to be taken in caries control

Efficiency of split-mouth designs

. The purpose of this paper is (1) to investigate the similarity of the amount, distribution, and, severity of periodontal disease of the within-patient experimental units, (2) to estimate the relative efficiencies of split-mouth designs when compared to whole-mouth designs, and (3) to discuss how stratification on initial pocket depth can result in large differences in the power of the test-statistics in the different disease categories. Periodontal disease characteristics are not always homogeneously distributed over the within-patient experimental units and this heterogeneity can reduce the efficiency of split-mouth designs. In particular, if analyses are stratified on initial pocket depth, sites with an initial probing depth deeper than 6 mm may be small in number and asymmetrically distributed when compared to sites with an initial probing depth less than 6 mm. This may result in large differences of the power of the test statistics among the different disease categories and should lead to a careful interpretation of the statistical significance tests. When disease characteristics are symmetrically distributed over the within-patient experimental units and a sufficient number of sites is present per experimental unit, the split-mouth design can provide moderate to large gains in relative efficiency. In the absence of a symmetric disease distribution, wholemouth clinical trials may be preferable.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75701/1/j.1600-051X.1990.tb01060.x.pd