Abstracts from the 85th General Session of the IADR: March 21-24, 2007, New Orleans, Louisiana.

These abstracts were among those presented at the 85th General Session of the International Association for Dental Research in New Orleans from March 21-24, 2007. The IADR has given us permission to publish a selection of abstracts in the journal.

CARIES 

0208 EFFECTS OF NOVEL FLUORIDE DENTTABS[R] ON REMINERALISATION OF WHITE-SPOT LESIONS

T. KREMNICZKY, W.H. ARNOLD, and P. GAENGLER, University of Witten/Herdecke, Germany

Objectives: It was the aim of this in-vitro-study to assess the remineralisation potential of a novel tooth cleaning tablet with different fluoride content. Methods: Twenty three caries free impacted wisdom teeth were examined, enamel surfaces were cleaned, wax coated leaving two 3x4mm windows for exposure to Demin./Remin. cycles. The teeth were randomly assigned to 4 Groups of 5 (control) teeth and 6 (experimental) teeth. Demin. by standardised HEC-gel, pH 4.7 at 37[degrees]C for 72h, was alternated by rinsing in standardised Remin. solution, pH 7.0 at 37[degrees]C for 72h, total challenge time 360h. The negative control Group N was treated during Remin. cycles with saline only; positive control Group P was treated with Remin. standardised solution; Denttabs[R]-experimental Group D1 was exposed to Remin. solution containing 1 Denttabs[R]-tablet with 1450ppmF per 5ml Remin. solution; Denttabs[R]-experimental Group D2 was rinsed with Remin. solution and Denttabs[R]-tablet with 4350ppmF. After the cycling each tooth was cut into serial sections to be analysed by polarising light microscopy and to assess quantitatively and semiqualitatively the different zones of white-spot lesions in the 3 most representative sections. The statistical analysis was based on the Mann-Withney-Test and Kruskal-Wallis-Test. Results: Both control Groups N(-) and P(+) exhibited microscopically and macroscopically characteristic white-spot lesions. The Remin. potential of the body of the lesion and of the total lesion increased considerably from N<P<D1<D2. Denttabs[R]-2 administration showed partial/total Remin including lamination and/or disappearance of the body of the lesion (mediane of 10 standard measurements per section of lesion extension in [micro]m: N 203.6; P 135.7; D1 71.4; D2 35.7). The different results of all 4 Groups were statistically with both tests highly significant (p<0.01). Conclusion: Based on these results the novel Denttabs[R] formulation represents a highly effective oral hygiene product and the Remin. potential is correlated to the fluoride content.

0500 CPP-ACP PASTE WITH FLUORIDE: IN VITRO ROOT SURFACE CARIES FORMATION

C.P. TRAITENBERG, University of Texas--Houston/Health Science Center, USA, C. FLAITZ, University of Texas Houston / Health Science Ctr, USA, and J. HICKS, Baylor College of Medicine, Houston, TX, USA

OBJECTIVE: This in vitro study evaluated the effects of a casein phosphopeptide-amorphous calcium phosphate paste (CPP-ACP) that contains fluoride on artificial caries formation in human root surfaces. METHODS: 15 human teeth with sound root surfaces were sectioned into 3 portions. Each portion from a single tooth was assigned to one of the three treatment groups: 1) CPP-ACP with No Fluoride (MI Paste, GC America, n=15); 2) FL-CPP-ACP with Fluoride Added (MI Paste with Fluoride, GC America, n=15); and 3) No Treatment Control (n=15). CPP-ACP and FL-CPP-ACP root segments were treated with the appropriate assigned agent for 120 seconds, followed by air-water rinsing for 60 seconds, and then exposed to synthetic saliva for 24 hours. CPP-ACP and FL-CPP-ACP treatment, rinsing and synthetic saliva exposure were repeated on a daily basis over a 14-day period. No treatment control root segments were exposed to synthetic saliva only for a 14-day period. Artificial root surface caries were created over a 10-day period (alternating 16 hours demineralization followed by 8 hours remineralization). Longitudinal sections (3 sections/root segment) were obtained and lesion depths were determined using polarized light microscopy (n=45 lesions/group, ANOVA, DMR). RESULTS: Mean root surface lesion depths were: 1) No Treatment Control Group: 326[+ or -]31um; 2) CPP-ACP Group: 268[+ or -]23um; 3) FL-CPP-ACP Group: 197[+ or -]26um. Mean lesion depth reductions compared with the No Treatment Control Group were: 18% for CPP-ACP Group (P<.05, ANOVA, DMR) and 39% for FL-CPP-ACP (P<.05, ANOVA, DMR). Mean lesion depth reduction for FL-CPP-ACP was 26% compared with CPP-ACP (P<.05, ANOVA, DMR). CONCLUSIONS: Treatment of root surfaces with CPP-ACP and Fl-CPP-ACP significantly improved caries resistance of root surfaces compared with the no treatment control group (P<.05). Incorporation of fluoride into CPP-ACP paste significantly lessened the effects of an in vitro root surface caries challenge compared with CPP-ACP alone (P<.05). (Funded by GC America, Inc.)

0502 EFFICACY OF MARKETED DENTIFRICES USING AN IN SITU CARIES MODEL

D. ZERO (1), H.M. PROSKIN (2), R.M. BUCH (3), C. KOLLAR (3), M.L. BOSMA (4), and S.R. SMITH (4), (1) Indiana University School of Dentistry, Indianapolis, USA, (2) Howard M. Proskin & Assoc, Rochester, NY, USA, (3) GlaxoSmithKline, Parsippany, NJ, USA, (4) GlaxoSmithKline, Weybridge, United Kingdom

Objectives: To compare the enamel fluoride uptake and remineralization potential of two commercially available dentifrices--containing either sodium fluoride/silica or sodium monofluorophosphate/sodium fluoride/dicalcium phosphate. Methods: 48 subjects participated in this 4 test period cross over and laboratory evaluator-blind study. There was a 1-week washout period between each test leg which included a 2-3 day lead-in with a dental prophylaxis followed by the use of non-fluoride dentifrice. Subjects' mandibular partial dentures were modified to hold partially demineralized enamel specimens in the buccal flange. Each test dentifrice was used for a two-week period. The products used were: test dentifrice containing 675ppm F from sodium fluoride/silica base; marketed dentifrice containing 1350ppm F from sodium fluoride/silica base (NaF); test dentifrice containing 2700ppm F from sodium fluoride/silica base; and a marketed dentifrice containing 1450ppm F (1000ppm F from sodium monofluorophosphate, 450ppm F from sodium fluoride) (MFP/NaF). The surface microhardness (SMH) test was used to assess changes in the mineral status of partially demineralized enamel specimens. Enamel fluoride uptake (EFU) of sound and partially demineralized enamel specimens was determined using the microdrill enamel biopsy technique (Sakkab et al., 1984). Results: After 14 days, the NaF dentifrice provided significantly greater %SMH Recovery (p= 0.0018) and significantly greater EFU (p<0.0001) than the MFP/NaF dentifrice. An increasing trend was observed for means of the three sodium fluoride dentifrices (675ppm F, 1350ppm F, and 2700ppm F) for the %SMH Recovery scores and for the EFU scores. Conclusion: This in situ study demonstrated that a dentifrice containing 1350ppm fluoride from sodium fluoride/silica base had significantly greater remineralization potential and fluoride uptake than a dentifrice containing a combination of 1000ppm fluoride from sodium monofluorophosphate and 450ppm F from sodium fluoride in a dicalcium phosphate base. A dose response was demonstrated for the sodium fluoride dentifrices.

1031 A NEW THEORY ABOUT THE DEVELOPMENT OF SECONDARY CARIES

N.J.M. OPDAM, B.A.C. LOOMANS, E.M. BRONKHORST, and J.J.M. ROETERS, Radboud University Nijmegen Medical Centre, Netherlands

Introduction: Secondary caries is considered to start at the outer surface of the tooth adjacent to a restoration in presence of an active biofilm. A carious lesion along the dentin-enamel junction (DEJ) detected after removal of a restoration is considered to be 'residual' caries (Mjor et al., 2000; Kidd, 2001). In this study it is hypothesized that cusp-movement during loading induces percolation and microleakage in absence of a biofilm with secondary caries at the DEJ as a result. The presence of a crack visible after removal of a restoration facilitates percolation. Objectives. To evaluate the relation between the presence of cracks and carious lesions along the dentin-enamel junction in teeth with an amalgam restorations. Methods: Premolar and molar teeth needing replacement of Class I and II amalgam restorations were included in this study. Exclusion criteria were teeth with restorations with marginal fractures, visible marginal cavitation (indicating presence of a carious lesion) or caries detected on a radiograph. In 99 teeth amalgam restorations were carefully removed including the corrosion products before cavity walls were visually inspected for the presence of caries at the DEJ and cracks in cusps. Data were statistically analyzed using a Chi-square test at p<0.05. Results: Statistical analysis revealed a significant effect of the presence of cracks and the presence of caries along the DEJ (p<0.001).

                     Cracks visible  No cracks visible

Caries along DEJ     36               7
No caries along DEJ  24              32

Conclusion: The outcome of the study suggests that in the development of secondary caries percolation due to the presence of cracks plays an important role.

SALIVA RESEARCH

1039 VARIATIONS IN SALIVARY CARIES PROTECTIVE FUNCTIONS IN HEALTHY INDIVIDUALS

M. KIM, A. CHAN, J. ALEKSEJUNIENE, and C. CLARK, University of British Columbia, Vancouver, Canada

The importance of saliva qualities to caries defense has been previously emphasized. Objectives: Study hypothesis: even in healthy individuals caries defense functions vary widely and are interrelated. Methods: Under standardization (no smoking, toothbrushing, eating, drinking for 60 min), following functions were studied: saliva flow rates (ml/min), stimulated saliva buffer capacity (scores 0-12), resting saliva pH (5.0 to 7.8). Saliva-Check kits were used for the pH and buffer capacity assessments. Glucose clearance (in M) was measured by glucose monitor at 3, 5, and 7 minutes after the glucose rinse. A fluoride retaining rate (in M/L) assessed at 0min, 5min, 10min, 15min and 20min after the 0.2% fluoride rinse. Counts of Mutans Streptoccocus and Lactobacilli in saliva grouped subjects into low, moderate or high caries risk groups. A convenience sample included healthy subjects (no diseases, neither medication use). The biological functions were related by Pearson correlation and significance set at P<0.05. Results: The resting saliva flow rate varied from 0.20 ml/min to 1.17 ml/min, the stimulated saliva from 0.33 ml/min to 3.11 ml/min, pH values were from 5.0 to 7.8 and buffer capacity scores from 6 to 12. The fluoride retaining rate varied most at 5minutes and least at 15 minutes after the fluoride rinse. There was a wide range of variation in glucose clearance patterns at all follow-up periods. These functions were interrelated (coefficient, P-value): the flow rate of resting with the pH of resting saliva (0.485, P=0.049) and the buffer capacity with glucose clearance time (0.626, P=0.012). Subjects with low and moderate risk caries groups presented better values of protective functions than subjects with high caries risk. Conclusion: A wide variation in each of studied protective functions was observed in healthy individuals. The protective functions such as pH, flow rate, buffer capacity and glucose clearance presented related effects.

CHILDREN

1665 TESTING A PROGRAM TO PREVENT EARLY CHILDHOOD CARIES: KNOWLEDGE OUTCOMES

S. LI, J. VERONNEAU, M.-C. LOIGNON, S. SHAPIRO, R.W. PLATT, and P.J. ALLISON, McGill University, Montreal, Canada

Objectives: To test the effectiveness of an educational program in the prevention of early childhood caries in Quebec, Canada. Methods: A community-based, multi-centre, single-blinded, randomised controlled trial design was used. A sample of 821 parent/child dyads was recruited when the infants were approximately 6 months old. The dyads were randomised to receive the test intervention or normal care (no service). The test intervention was an educational program in which dental hygienists delivered caries-prevention material to the dyads on a one-on-one basis on four occasions, at 6 month intervals. Baseline sociodemographic, socioeconomic, and caries-related knowledge and behaviour data were collected from parents at recruitment. The same data were collected 24 months following recruitment. Knowledge variables concerned dietary and bacterial causes of caries and means to prevent caries. These variables were evaluated by parents using a self-complete questionnaire. Knowledge variables were described using the percentage of parents marking the most appropriate response. Knowledge variables at outcomes evaluation were compared between test and control groups using a chi square test. Results: Of the 821 dyads recruited, 749 (91.2%) were seen for outcomes evaluation. There were no differences in sociodemographic and socioeconomic characteristics between those completing the study and those dropping out. Of 11 knowledge variables, the test group obtained a significantly higher percentage of appropriate responses than the control group for 6 variables, 1 variable was of borderline difference in the same direction and 4 variables showed no difference between groups. Following a Bonferonni correction for multiple tests, five variables were different between the groups. Knowledge of cross-infection control, oral hygiene practices and some dietary issues were different while other diet-related knowledge was similar between groups. Conclusion: The test intervention appears to have some effect on caries-related knowledge of parents of 30 month old children. Funding by the Canadian Institutes of Health Research.

2430 EARLY ENAMEL DEFECTS LEADING TO EARLY CHILDHOOD CARIES: COHORT STUDY

A. ROSENBLATT, A. RIBEIRO, A. OLIVIERA, and A.M. CHAVES, Universidade De Pernambuco, Recife, Brazil

Objective: The purpose of this study was to determine if enamel defects might be a good predictor of subsequent early childhood caries. Method: Using a prospective cohort design, low income Brazilian children, from birth to 54 months of age, were examined at home, at 6 month intervals, with natural light using dental mirror, probe (WHO), by the knee-to-knee technique. The teeth were cleaned with gauze and teeth were examined for enamel defects using the Development Defects Enamel (DDE) index and caries was registered according to the WHO criteria. Two groups were identified: those with and those without early enamel defects. To control for confounding variables, we also examined breastfeeding, diet, oral hygiene and exposure to fluoride. Descriptive statistics, non parametric tests, and logistic regression models were performed. Results: At 54 months 48.3% of the subjects with enamel defects and 26.2% of the subjects without enamel defects developed early childhood caries (ECC) (p=0.02). Among all enamel defects, enamel hypoplasia demonstrated the highest risk of subsequent caries. Further, in the multivariate analyses, at 54 months, only enamel defects significantly correlated with caries (p= 0.001). Conversely, only fluoride use was significantly protective against ECC (p= 0.02). Conclusion: Enamel defects are very strong predictors of ECC development.

2206 TWO EFFICACY STUDIES OF A CHILDREN'S PRE-BRUSH PLAQUE TINTING MOUTHRINSE

C. CHARLES (1), T. LISANTE (1), Q. ZHAO (1), J. QAQISH (2), M.C. LYNCH (1), C.R. GOYAL (2), and N. SHARMA (2), (1) Pfizer Inc.-, Morris Plains, NJ, USA, (2) Biosci Research Canada, Ltd, Mississauga, Canada

Objectives: To determine the efficacy of Listerine[R] Agent Cool Blue[TM] Plaque-Detecting Rinse (ACB) in helping children remove plaque from their teeth when used before brushing, twice daily, over a 30-day period in two randomized, examiner-blind, single-center, parallel-group design, clinical trials. The secondary objectives were to monitor oral tissue tolerance and to assess gingivitis levels. Methods: Following IRB approval about 100 (50 per treatment group) generally healthy 6-12 year old children who met the necessary inclusion/exclusion criteria were enrolled in each study. They rinsed twice daily (10 ml for 30 seconds) with their assigned mouthrinse, before brushing. An ADA-Accepted children's toothbrush and fluoride toothpaste were dispensed for home use for 30 days. Oral tissues, gingivitis (Modified Gingival Index [MGI]), and plaque (Turesky Modification of the Quigley-Hein Plaque Index [PI] scored on 6 surfaces) examinations took place at baseline and after 15 and 30 days of use. Compliance was assessed by reviewing subject diaries and supplies. Results: ACB demonstrated 13.5% and 22.1% reduction in PI at day 30, in studies 1 and 2, respectively, compared to control (p<0.001). In addition, ACB reduced MGI by 7.0% in study 1 (p<0.001), and 19.6% in study 2 (p<0.001), compared to control. Conclusions: Listerine[R] Agent Cool Blue[TM] Plaque-Detecting Rinse was well tolerated and when used twice daily, before brushing, provided statistically significant reductions in both plaque and gingival indices.

2116 CARIES DEVELOPMENT IN TEETH OF CHILDREN REGULARLY ATTENDING A DENTIST

K.M. MILSOM (1), A. THRELFALL (2), A. BLINKHORN (2), and M. TICKLE (2), (1) University of Manchester, Chester, United Kingdom, (2) University of Manchester, United Kingdom

Objectives: To measure the incidence of dental caries in primary molar teeth of children aged 3-6 years who attended NHS dental services in the Northwest of England. To measure the outcomes of dental restorative treatment in this group of children. Methods: Detailed dental records of children born between 03.07.95 and 23.12.97 attending the practices of 50 volunteer NHS dentists in the Northwest of England were assembled over a period of three years. Data from these records were analysed to estimate caries incidence rates at the subject and tooth level. Results: The study population consisted of 739 children aged between 2.8 and 6.2 years at baseline. At the start of the study, 620 children (84%) were caries free. The age specific incidence of a first caries event in caries free children increased with age. At age four the incidence of the first carious lesion was 9.5 per 100 person years and at age seven it was 19.6 per 100 person years. The tooth specific incidence of caries was found to be approximately five times greater in children that already had caries recorded than in children that did not have any caries at baseline. A sub-analysis was undertaken on 566 children that were continuously followed for more than 2 years. Out of 486 children with no caries at baseline 132 (27%) developed caries in molars during follow-up. By contrast, of 79 children with one or more carious primary molars at baseline, 57 (71%) developed further carious lesions. Conclusion: Due to the substantially different risk of developing new cavities, children who present with caries should be considered as a different population to those who are caries free. The principal aim of public health and primary care preventive strategies should be to keep young children caries free.

WHITENING

0121 CLINICAL EFFICACY OF TWO DIRECT-TO-CONSUMER WHITENING STRIPS

I. MAGNUSSON (1), B. HALES (1), B. THACKER (1), K. KARPINIA (1), M.L. BARKER (2), and S. FARRELL (2), (1) University of Florida, Gainesville, USA, (2) The Procter & Gamble Company, Mason, OH, USA

[Check symbols in this] Objective: This clinical study compared efficacy of two direct-to-consumer whitening strips. Methods: 57 subjects were randomized to one of two whitening regimens: Oral-B[R] Rembrandt[R] Whitening Strips Premium worn once a day for 7 days (7-day strips) or Crest[R] Whitestrips[R] Premium Plus containing 10% hydrogen peroxide and worn twice a day for 10 days (10-day strips). Treatment followed the manufacturers written instructions which included 30 minutes wear time per strip application. Tolerability was assessed from subject interviews and oral examination, and efficacy was measured objectively from CIELAB digital measurements. Whitening response was compared at Day 6, Day 8 and at the end-of-treatment (Day 8 for the 7-day strip and Day 11 for the 10-day Strip) using the analysis of covariance method. Results: The study population consisted of healthy adults averaging 30.3 years of age. At each study visit, the 10-day strip group demonstrated significantly greater improvement of b* and L* (p " 0.0051) relative to the 7-day strip group. At the end-of-treatment, use of 7-day strips resulted in adjusted means of -1.19 for [DELTA]b* and 1.30 for [DELTA]L*, while the use of 10-day strips resulted in adjusted means of -2.32 for [DELTA]b* and 2.23 for [DELTA]L*. The 10-day strip group demonstrated significantly greater (p < 0.0001) tooth color improvement (both [DELTA]b* and [DELTA]L*) relative to the 7-day strip group at end-of-treatment. Both treatments were generally well-tolerated. Conclusion: Use of a direct-to-consumer 10% hydrogen peroxide, 10-day whitening strip resulted in a significantly greater tooth whitening response relative to that of a 7-day marketed strip.

2666 BLEACHING EFFECT COMPARISON OF TWO DIFFERENT CONCENTRATIONS OF HYDROGEN PEROXIDE

S. KIM-PUSATERI, S. CIANCIO, and M. BESSINGER, State University of New York--Buffalo, USA

Objective: To compare the effectiveness of two concentrations of a chairside bleaching agent. Methods: A total of 76 teeth in 19 subjects were evaluated. Included were non-restored maxillary incisors with baseline shade of B54 (Trubyte) or darker. Eligible subjects were randomly assigned to groups receiving either 25% or 32% hydrogen peroxide (Sapphire Bleaching System). Subjects received either two 30 or three 20 minute applications of the bleaching agent following the manufacturers instructions. Variables were evaluated at baseline, immediate post-treatment, and one week post-treatment: tooth shade, gingival index, plaque index, tooth sensitivity. L*a*b* values were measured using a commercial dental colorimeter (ShadeVision, X-Rite) and delta E values were calculated. Data was analyzed using a two-sample independent t-test at 95% confidence level. Results: There was no significant change in gingival index, plaque index, or sensitivity following treatment (p>0.05). There was no significant difference in delta E or visual shade values for groups receiving 25% or 32% hydrogen peroxide following two applications (p=0.14) or three (p=0.85). Three applications of 25% and 32% gave shade changes (x(SEM)) of 11.1(0.78) and 12.0(0.38), and for two applications 11.3(0.74) vs. 12.2(0.87) with the differences being non significant (P>0.05). One week post treatment no significant shade changes were noted (P>0.05). Conclusions: Both concentrations (25% and 32%) of hydrogen peroxide had similar bleaching effect. This finding was seen both with visual scoring and with colorimetric evaluations. Use of the products three times showed no advantage over using twice. No adverse effects on gingival tissues or tooth sensitivity were found. Changes in visual and colorimetric scores one week post bleach were minimal, suggesting that both products effects were due to bleaching and not to osmotic changes at the time of bleaching. Supported, in part, by a grant from DenMat Corp.

PERIODONTOLOGY 

1843 PREVALENCE OF PERIODONTAL DISEASE IN THE UNITED STATES: NHANES 1999-2004

P. EKE, Center for Disease Control, Atlanta, GA, USA, and L. BARKER, U.S. Centers for Disease Control and Prevention, Atlanta, GA, USA

Objective: To estimate the prevalence of moderate and severe periodontal disease among dentate adults in the U.S. population. Methods: National prevalence of moderate and severe periodontal diseases among dentate adults aged 20 years and older was estimated from the 1999-2004 National Health and Nutrition Examination Survey (NHANES). Analysis was limited to the mesial probing site on each of 28 teeth, exclusive of 3rd molars; distal site data were not available for 1999-2000. Moderate disease was defined as two or more interproximal sites with [greater than or equal to] 4 mm clinical attachment loss (CAL), or two or more interproximal sites with [greater than or equal to] 5 mm Probing Pocket Depth (PPD). Severe disease was defined as two or more interproximal sites with [greater than or equal to] 6 mm CAL, and one or more interproximal sites with [greater than or equal to] 5 mm PPD.

Results:

Prevalence* of Moderate and Severe Periodontal Disease: 1999-2004

Age Group  % Moderate PD (se)  % Severe PD (se)

20-34       0.82 (0.21)        0.06 (0.05)
35-49       4.32 (0.67)        0.48 (0.24)
50-64       9.98 (0.96)        1.68 (0.50)
65-74      13.11 (1.49)        1.54 (0.46)
75+        18.32 (2.47)        2.90 (0.84)
Total       6.42 (0.50)        0.90 (0.15)

*Age and sex adjusted to U.S. 2000 standard population. Overall, the
prevalence of moderate and severe periodontal disease ranged from 0.82%
to 18.3% and 0.06% to 2.9% for adults aged 20-34 years, and adults aged
75 years and older, respectively. Moderate disease was most prevalent in
males, non-Hispanic blacks, the lowest family poverty ratio group
(<100%), and persons with less than high school education. Severe
disease was more prevalent among males than females for all age groups
(except those aged 75 years and older), persons with family poverty
income ratio between 100%-200%, and those with less than high school
education.

Conclusion: Severe and moderate periodontitis is still prevalent in the U.S. Moderate disease, which is most amenable to preventive measures, was most prevalent in non-Hispanic black males, the poorest and least educated.