Kiet A. Ly

Mutans Streptococci Dose Response to Xylitol Chewing Gum

Xylitol is promoted in caries-preventive strategies, yet its effective dose range is unclear. This study determined the dose-response of mutans streptococci in plaque and unstimulated saliva to xylitol gum. Participants (n = 132) were randomized: controls (G1) (sorbitol/maltitol), or combinations giving xylitol 3.44 g/day (G2), 6.88 g/day (G3), or 10.32 g/day (G4). Groups chewed 3 pellets/4 times/d. Samples were taken at baseline, 5 wks, and 6 mos, and were cultured on modified Mitis Salivarius agar for mutans streptococci and on blood agar for total culturable flora. At 5 wks, mutans streptococci levels in plaque were 10x lower than baseline in G3 and G4 (P = 0.007/0.003). There were no differences in saliva. At 6 mos, mutans streptococci in plaque for G3 and G4 remained 10x lower than baseline (P = 0.007/0.04). Saliva for G3 and G4 was lower than baseline by 8 to 9x (P = 0.011/0.038). Xylitol at 6.44 g/day and 10.32 g/day reduces mutans streptococci in plaque at 5 wks, and in plaque and unstimulated saliva at 6 mos. A plateau effect is suggested between 6.44 g and 10.32 g xylitol/day.

Xylitol pediatric topical oral syrup to prevent dental caries: a double blind, randomized clinical trial of efficacy

OBJECTIVES To evaluate the effectiveness of a xylitol pediatric topical oral syrup to reduce the incidence of dental caries among very young children and to evaluate the effect of xylitol in reducing acute otitis media in a subsequent study. DESIGN Double-blind randomized controlled trial. SETTING Communities in the Republic of the Marshall Islands. PARTICIPANTS One hundred eight children aged 9 to 15 months were screened, and 100 were enrolled. Intervention Children were randomized to receive xylitol topical oral syrup (administered by their parents) twice a day (2 xylitol [4.00-g] doses and 1 sorbitol dose) (Xyl-2 x group) or thrice per day (3 xylitol [2.67-g] doses) (Xyl-3x group) vs a control syrup (1 xylitol [2.67-g] dose and 2 sorbitol doses) (control group). MAIN OUTCOME MEASURES The primary outcome end point of the study was the number of decayed primary teeth. A secondary outcome end point was the incidence of acute otitis media for reporting in a subsequent report. RESULTS Ninety-four children (mean [SD] age, 15.0 [2.7] months at randomization) with at least 1 follow-up examination were included in the intent-to-treat analysis. The mean (SD) follow-up period was 10.5 (2.2) months. Fifteen of 29 of the children in the control group (51.7%) had tooth decay compared with 13 of 32 children in the Xyl-3x group (40.6%) and eight of 33 children in the Xyl-2x group (24.2%). The mean (SD) numbers of decayed teeth were 1.9 (2.4) in the control group, 1.0 (1.4) in the Xyl-3x group, and 0.6 (1.1) in the Xyl-2x group. Compared with the control group, there were significantly fewer decayed teeth in the Xyl-2x group (relative risk, 0.30; 95% confidence interval, 0.13-0.66; P = .003) and in the Xyl-3x group (0.50; 0.26-0.96; P = .04). No statistical difference was noted between the 2 xylitol treatment groups (P = .22). CONCLUSION Xylitol oral syrup administered topically 2 or 3 times daily at a total daily dose of 8 g was effective in preventing early childhood caries.

Xylitol and Its Vehicles for Public Health Needs

Xylitol has been demonstrated to be a safe and effective tooth decay preventive agent when used habitually. Nevertheless, its application has been limited by absence of formulations that demand minimal adherence and are acceptable and safe in settings where chewing gum may not be allowed. A substantial literature suggests that a minimum of five to six grams and three exposures per day from chewing gum or candies are needed for a clinical effect. At the same time there is conflicting evidence in the literature from toothpaste studies suggesting that lower-doses and less frequent exposures might be effective. The growing use of xylitol as a sweetener in low amounts in foods and other consumables is, simultaneously, increasing the overall exposure of the public to xylitol and may have additive benefits.

Methicillin-resistant Staphylococcus aureus from dental school clinic surfaces and students

BACKGROUND Methicillin-resistant Staphylococcus aureus (MRSA) isolated from frequently touched dental school clinic surfaces were compared with MRSA isolated nasal cultures of dental students. METHOD Sixty-one dental students and 95 environmental surfaces from 7 clinics were sampled using SANICULT (Starplex Scientific Inc, Etobicoke, Ontario, Canada) swabs. Antimicrobial susceptibility testing was performed, and pulsed-field gel electrophoresis analysis, the mecA gene, multilocus sequence type, and SCCmec type were determined by polymerase chain reaction and sequencing. RESULTS Thirteen (21%) dental students and 8 (8.4%) surfaces were MRSA positive. Three MRSA strains were SCCmec type IV, whereas 3 were nontypeable isolates and Panton-Valentine leukocidin positive (PVL+), and none were USA300. One surface and 1 student isolate shared the same multilocus sequence type ST 8 and were 75% related. Two groups of students carried the same MRSA strains. CONCLUSION The MRSA-positive samples were from 4 of 7 dental clinics. In addition, 21% of the dental students carried MRSA, which is > 10 times higher than the general public and twice as frequent as in other university students. This is the first study to characterize MRSA from dental clinic surfaces and dental students and suggests that both may be reservoirs for MRSA. Further studies are needed to verify this premise.

Linear response of mutans streptococci to increasing frequency of xylitol chewing gum use: a randomized controlled trial [ISRCTN43479664]

BackgroundXylitol is a naturally occurring sugar substitute that has been shown to reduce the level of mutans streptococci in plaque and saliva and to reduce tooth decay. It has been suggested that the degree of reduction is dependent on both the amount and the frequency of xylitol consumption. For xylitol to be successfully and cost-effectively used in public health prevention strategies dosing and frequency guidelines should be established. This study determined the reduction in mutans streptococci levels in plaque and unstimulated saliva to increasing frequency of xylitol gum use at a fixed total daily dose of 10.32 g over five weeks.MethodsParticipants (n = 132) were randomized to either active groups (10.32 g xylitol/day) or a placebo control (9.828 g sorbitol and 0.7 g maltitol/day). All groups chewed 12 pieces of gum per day. The control group chewed 4 times/day and active groups chewed xylitol gum at a frequency of 2 times/day, 3 times/day, or 4 times/day. The 12 gum pieces were evenly divided into the frequency assigned to each group. Plaque and unstimulated saliva samples were taken at baseline and five-weeks and were cultured on modified Mitis Salivarius agar for mutans streptococci enumeration.ResultsThere were no significant differences in mutans streptococci level among the groups at baseline. At five-weeks, mutans streptococci levels in plaque and unstimulated saliva showed a linear reduction with increasing frequency of xylitol chewing gum use at the constant daily dose. Although the difference observed for the group that chewed xylitol 2 times/day was consistent with the linear model, the difference was not significant.ConclusionThere was a linear reduction in mutans streptococci levels in plaque and saliva with increasing frequency of xylitol gum use at a constant daily dose. Reduction at a consumption frequency of 2 times per day was small and consistent with the linear-response line but was not statistically significant.

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

BackgroundHabitual 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.MethodsChildren, 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.ResultsThere were no differences in S. mutans/sobrinus and Lactobacillus spp. levels in plaque between the groups at baseline. At six weeks, log10S. 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.ConclusionReductions 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]

Using photovoice to understand cardiovascular health awareness in Asian elders.

Photovoice, a qualitative methodology using photography by study participants, is an ideal tool for collecting information on awareness of cardiovascular health from the perspective of persons of different cultural backgrounds and English-speaking abilities who are often subject to health disparities. Participants of Chinese, Vietnamese, and Korean ethnicity were provided disposable cameras to photograph their perceptions of scenes promoting or acting as barriers to cardiovascular health. After the pictures were developed, they returned for a discussion in their native languages to contextualize the stories told in their photographs. Group facilitators spoke the respective native languages and transcribed sessions into English. Twenty-three adults participated (7 to 9 persons per ethnicity), ranging in age from 50 to 88 (mean 71.6) years; 48% were women. The photographs stimulated conversations of knowledge, beliefs, and concerns regarding heart disease and stroke. Issues surrounding food and exercise were most dominant across ethnic groups, focusing on fat and salt intake and the need to remain active. Cultural beliefs and issues of emotional health, including stress and loneliness related to living in a new country, were also depicted. Photovoice provided insight into perceptions of cardiovascular health that is vital for developing health promotion and education interventions in limited–English-speaking communities.

An FQHC Research Network in Oral Health: Enhancing the Workforce and Reducing Disparities

Federally Qualified Health Centers (FQHCs) contribute greatly to reducing health disparities by providing care to underserved communities. Yet these safety-net clinics face chronic manpower shortages and turnover. Practice-Based Research Networks aid in translating medical science from bench to clinical practice. These networks have been used to understand and improve health-care delivery and reduce disparities. Initiatives to strengthen lagging translational research in dentistry have begun, but there is no FQHC research network that addresses oral health. This article reviews the potential for, and outlines a model of, an Oral Health FQHC Research Network. It characterizes the needs for an FQHC research network, describes a successful FQHC research-oriented program, and outlines an Oral Health FQHC Research Network conceptual model. It argues that strengthening FQHCs through involvement of their dental staff in clinical research may enhance their jobs, draw staff closer to the community, and strengthen their ability to reduce health disparities.

Double burden: a cross-sectional survey assessing factors associated with underweight and overweight status in Danang, Vietnam

BackgroundMany low- to middle-income countries are faced with an increasing prevalence of overweight/obesity while that for underweight remains high, a duality termed “double burden”; both are key risk factors for chronic diseases. This cross-sectional study assesses the prevalence and factors for underweight and overweight/obesity among adults in Danang, Vietnam, using WHO standard and suggested Asian-specific BMI cut-offs.MethodsIn 2010, 1713 residents age ≥35 years from 900 households in 6 of 56 urban, rural and mixed urban–rural communes in Danang were selected using multistage-cluster sampling methodology to participate; 1621 qualified adults enrolled. Participants completed a health survey based on WHO STEPwise Approach to Chronic Disease Risk Factor Surveillance and additional questions on chest pain and stroke symptoms. Anthropometric and other measurements were conducted. Relative risk regression was used to identify independent risk factors for underweight or overweight/obesity according to WHO standard cut-offs and suggested Asian-specific cut-offs (<18.5 kg/m2 or 23–27.49 kg/m2; and ≥27.5 kg/m2).ResultsWe observed 12.4% prevalence of underweight and 16.0% for overweight/obesity using WHO standard. The prevalence of overweight/obesity doubled (33.7%) when Asian-specific cut-offs were applied. For both definitions, rural communes had the highest prevalence of underweight while urban communes had the highest prevalence of overweight/obesity. Being underweight was associated with less urbanization. Factors independently associated with being underweight included older age, rural living, current smoking, and lower systolic pressure. Factors independently associated with Asian-specific BMI definition for being overweight/obese included older age, urbanization, higher systolic pressure, and diabetes. Age was not an independent factor with WHO standard cut-offs; however, myocarial infarction and diabetes showed strong associations.ConclusionsThe double burden of underweight and overweight/obesity observed in Danang is consistent with patterns found for large cities in Vietnam that are undergoing rapid economic growth and urbanization of lifestyle. Factors independently associated with underweight and overweight/obesity status by WHO standard and Asian-specific definitions include urbanization and modifiable lifestyle factors. Further studies are needed to define ethnic specific BMI cut-offs for Vietnam and to explore strategies to reduce the rising prevalence of overweight/obesity.

A prospective cohort study of stroke characteristics, care, and mortality in a hospital stroke registry in Vietnam.

BackgroundAs low and middle-income countries such as Vietnam experience the health transition from infectious to chronic diseases, the morbidity and mortality from stroke will rise. In line with the recommendation of the Institute of Medicine’s report on “Promoting Cardiovascular Health in the Developing World” to “improve local data”, we sought to investigate patient characteristics and clinical predictors of mortality among stroke inpatients at Da Nang Hospital in Vietnam.MethodsA stroke registry was developed and implemented at Da Nang Hospital utilizing the World Health Organization’s Stroke STEPS instrument for data collection.Results754 patients were hospitalized for stroke from March 2010 through February 2011 and admitted to either the intensive care unit or cardiology ward. Mean age was 65 years, and 39% were female. Nearly 50% of strokes were hemorrhagic. At 28-day follow-up, 51.0% of patients with hemorrhagic stroke died whereas 20.3% of patients with ischemic stroke died. A number of factors were independently associated with 28-day mortality; the two strongest independent predictors were depressed level of consciousness on presentation and hemorrhagic stroke type. While virtually all patients completed a CT during the admission, evidence-based processes of care such as anti-thrombotic therapy and carotid ultrasound for ischemic stroke patients were underutilized.ConclusionsThis cohort study highlights the high mortality due in part to the large proportion of hemorrhagic strokes in Vietnam. Lack of hypertension awareness and standards of care exacerbated clinical outcomes. Numerous opportunities for simple, inexpensive interventions to improve outcomes or reduce recurrent stroke have been identified.