Characterization of the Abuse Potential in Adult Smokers of a Novel Oral Tobacco Product Relative to Combustible Cigarettes and Nicotine Polacrilex Gum.

Novel noncombustible tobacco products offer adult smokers (ASs) alternatives to combustible cigarettes lower on the continuum of risk; however, the abuse potential of such products has not been well studied. The objective of this study was to evaluate the abuse potential of 2 chewable tobacco-derived nicotine containing products, VERVE Chews Blue Mint (test 1) and Green Mint (test 2), in ASs compared with own-brand cigarettes (CIGS) and nicotine polacrilex gum (GUM) using subjective measures and nicotine pharmacokinetics. ASs used the test products during a 5-day at-home trial prior to completing an in-clinic 4-period randomized crossover study. During the study ASs used test products, CIGS, and GUM once on separate days. Responses to Tobacco/Nicotine Withdrawal and Direct Effects of Product questionnaires were documented, and blood samples were collected to assess nicotine pharmacokinetics during each product use. Nicotine pharmacokinetic parameters (Cmax and AUC) were statistically significantly lower with use of test products compared with CIGS and statistically significantly higher compared with GUM. No appreciable differences were noted between the 2 flavors for any of the end points measured. Reductions in maximum urge to smoke and maximum responses to the question "Is the Product 'Pleasant' Right Now?" for the test products were statistically significantly lower than CIGS but comparable to GUM. Similar results were observed for responses to other items in the 2 questionnaires. The test products, under the conditions of this study, carry lower abuse potential than own-brand cigarettes and similar to nicotine polacrilex gum.

Using Nicotine Gum to Assist Nondaily Smokers in Quitting: A Randomized Clinical Trial.

INTRODUCTION: Non-daily intermittent smokers (ITS) comprise 30% of US adult smokers. ITS smoke for nicotine and have trouble quitting, but tend to smoke in particular situations. This study tested the effect of nicotine gum, used to prevent or react to situational temptations, for helping ITS quit. METHODS: ITS (smoking 4-27 days/month) seeking help quitting were randomized to 2 mg nicotine gum (n = 181) or placebo (n = 188), to be used to anticipate or react to temptations to smoke, for 8 weeks. Participants received up to six sessions of behavioral counseling. The primary outcome was 6-month biochemically verified continuous abstinence; analyses also examined 14-day point-prevalence abstinence at multiple time points, and used event-history analyses to assess progression to abstinence, lapsing, and relapsing. Analyses adjusted for group differences in age and baseline smoking, and considered several potential moderators of treatment effects. RESULTS: Nicotine gum did not significantly improve outcomes on any measure. Biochemically verified 6-month continuous abstinence rates were 7.2% for active gum and 5.3% for placebo (AOR = 1.39, 0.58-3.29, p > .25). ITS with any degree of dependence (Fagerstrom Test of Nicotine Dependence scores >0) showed poorer outcomes on multiple endpoints, and did more poorly on active gum on some outcomes. Gum use was low, starting at 1 gum per day on average and declining over time. CONCLUSIONS: Nicotine gum (2 mg), used intermittently, did not improve cessation rates among ITS, including those demonstrating some degree of dependence. IMPLICATIONS: Nicotine replacement has been extensively tested with daily smokers, especially those who smoke relatively heavily. Nondaily smoking is now common, creating a need for treatment for ITS. Despite evidence that ITS' smoking is motivated by nicotine-seeking, a theoretically and empirically derived situational approach to using acute nicotine replacement was not successful at helping ITS quit. Gum use was low; whether higher or more frequent dosing is needed, or whether an entirely different approach is needed, is not clear. Effective treatment options are needed for ITS, especially those with some degree of dependence.

Prevalence of Temporomandibular Joint Disorders and its Association with Para Functional Habits in the Patients Attending Tertiary Care Hospital.

BACKGROUND: Temporo-mandibular disorders is a collective term used to describe problems involving muscles of mastication and temporomandibular joint. The study aimed to evaluate the prevalence of temporo-mandibular disorders and its association with parafunctional habits in patients visiting department of dentistry, Patan Academy of Health Sciences. METHODS: A cross-sectional study was carried out among 213 patients coming to Patan Academy of Health Sciences. A screening questionnaire recommended by American Association of Orofacial Pain was used to determine the signs and symptoms of temporo-mandibular disorders. RESULTS: The prevalence of temporomandibular disorders was 31.9 %. The three most common parafunctional habits were chewing gums (32.4 %), mouth breathing (19.7 %) and biting of objects (14.6 %) respectively. Statistically significant association was found between nail biting, grinding of teeth, biting of lips and objects and mouth breathing with signs and symptoms of temporomandibular disorders (p<0.05). Among the signs and symptoms of temporomandibular disorders, getting headaches, neck pain or toothaches often was the most frequent signs of temporomandibular disorders (n=105, 49.3 %). Feeling of recent change in bite was the second most frequent sign reported by 82 participants (38.5 %). CONCLUSIONS: The parafunctional habits between nail biting, grinding of teeth, biting of lips and objects and mouth breathing have statistically significant association with signs and symptoms of temporomandibular disorders.

Natural versus enriched food: Evidence from a laboratory experiment with chewing gum.

The current study explored consumers' preferences for natural versus enriched foods and identified the underlying driving forces behind consumer interest towards both attributes. A laboratory experiment with 200 respondents was carried out, applying the incentive compatible Becker-DeGroot-Marschak mechanism to measure consumers' willingness to pay for natural and enriched attributes of chewing gum. Empirical findings reveal that the two attributes are evaluated similarly by consumers. Furthermore, structural equation modelling identified a strong interdependence between the natural and the enriched attributes, suggesting they are complementary rather than substitutes/alternatives in consumers' food choices. Indeed, preferences for natural and for enriched attributes are influenced by different motivations nonetheless share a common driver: the general interest for healthy food.

Elevating the use of sugar-free chewing gum in Germany: cost saving and caries prevention.

OBJECTIVE: To analyse the lifetime monetary and health related effects of the consumption of sugar-free chewing gum. MATERIAL AND METHODS: Using a Markov model we assumed that the German consumption of sugar-free chewing gum (111 gums/year) could be elevated to the level of Finland (202 gums/year). The calculation was based on a model patient representing the development of oral health from the age of 12 to 74 years and clinical data on the effectiveness of chewing sugar-free gum. Lifetime and yearly costs for the 'Finland-scenario' were determined and compared with the actual German expenses of the statutory health insurance companies for dental health. RESULTS: The actual total lifetime expenditures of the statutory health insurance companies are 17,199.96€ per capita and would be 12,188.94€ in the scenario with elevated consumption of sugar-free chewing gum in Germany. Thus, 5011.02€ per capita could be saved in a lifetime and 80.82€ per year. CONCLUSIONS: On a national scale, the elevation of the consumption of sugar-free chewing gum in Germany to the level of Finland would lead to a considerable benefit for cost saving and oral health for the statutory health insurance companies.

The Effect of Gum Chewing, Early Oral Hydration, and Early Mobilization on Intestinal Motility After Cesarean Birth.

AIM: The aim of the study was to investigate the effect of gum chewing, early oral hydration, and early mobilization after cesarean birth on intestinal sounds, passing gas, and intestinal evacuation. DESIGN: Randomized controlled study. SETTING: This study was conducted at the Obstetrics Service of the one Obstetrics and Child Diseases Hospital. PARTICIPANTS: A total of 240 females divided into 8 groups of 30 subjects each were included within the scope of the sample. METHODS: The women who underwent cesarean birth were divided into eight groups by using 2(3) factorial test levels, depending on the use of three different methods of gum chewing, early oral hydration, and early mobilization. No intervention was applied to the women in the control group. For the other seven groups, the intestinal sounds were checked every 30 minutes with a stethoscope over the abdomen and the first time of passing gas and the first evacuation time were recorded by asking the mother. The data were evaluated with numbers, mean, and percentage calculations, Student's t test, one-way variance analysis, correlation, and Tukey HSD test. RESULTS: The intestinal sounds were heard earlier, gas was passed earlier, and bowel movements were earlier in the first group that received all interventions compared to the other groups (p < .05). The patient could not be discharged before 48 hours had passed after the cesarean birth according to the hospital protocol and the time of discharge was therefore not affected by interventions. LINKING EVIDENCE TO ACTION: All of the three different interventions, such as gum chewing, early oral hydration, and early mobilization after cesarean birth, increase intestinal motility. The interventions are recommended during postoperative routine care to shorten hospital stay and prevent postoperative ileus.

Effects of chewing on cognitive processing speed.

In recent years, chewing has been discussed as producing effects of maintaining and sustaining cognitive performance. We have reported that chewing may improve or recover the process of working memory; however, the mechanisms underlying these phenomena are still to be elucidated. We investigated the effect of chewing on aspects of attention and cognitive processing speed, testing the hypothesis that this effect induces higher cognitive performance. Seventeen healthy adults (20-34 years old) were studied during attention task with blood oxygenation level-dependent functional (fMRI) at 3.0 T MRI. The attentional network test (ANT) within a single task fMRI containing two cue conditions (no cue and center cue) and two target conditions (congruent and incongruent) was conducted to examine the efficiency of alerting and executive control. Participants were instructed to press a button with the right or left thumb according to the direction of a centrally presented arrow. Each participant underwent two back-to-back ANT sessions with or without chewing gum, odorless and tasteless to remove any effect other than chewing. Behavioral results showed that mean reaction time was significantly decreased during chewing condition, regardless of speed-accuracy trade-off, although there were no significant changes in behavioral effects (both alerting and conflict effects). On the other hand, fMRI analysis revealed higher activations in the anterior cingulate cortex and left frontal gyrus for the executive network and motor-related regions for both attentional networks during chewing condition. These results suggested that chewing induced an increase in the arousal level and alertness in addition to an effect on motor control and, as a consequence, these effects could lead to improvements in cognitive performance.

Effects of chewing gum on stress and health: a replication and investigation of dose-response.

Research suggests that chewing gum may be associated with reduced stress, depression and a reduced likelihood of having high cholesterol and blood pressure. The present study aimed to replicate these findings and extend them by examining dose-response. A web-based survey was completed by a sample of 388 workers from public sector organisations (68.5% female; mean age: 42 years, range 17-64 years). The results showed that chewing gum was associated in a linear dose-response manner with lower levels of perceived stress (both at work and life in general), anxiety and depression. Occasional gum chewers also reported a reduced risk of high cholesterol and blood pressure. Intervention studies are now required to extend these findings, and the mechanisms underlying the effects reported here need further investigation.

History of frequent gum chewing is associated with higher unstimulated salivary flow rate and lower caries severity in healthy Chinese adults.

This was a single-center, prospective, cross-sectional study stratified by age and gender with the objective of determining the relationship between gum chewing history, salivary flow, and dental caries severity in adults. We enrolled 191 subjects aged 18-65 years who underwent assessments for gum chewing history, unstimulated salivary flow rate, salivary pH, and caries severity. Unstimulated salivary flow rate tended to decline with increasing age (p = 0.04), and significant differences in unstimulated salivary flow rate were also found for males (0.58 ± 0.32 ml/min) versus females (0.48 ± 0.30 ml/min) (p = 0.02). Weekly gum chewing frequency was greater in younger subjects (p = 0.001) while no age group differences were noted in pieces per day or chewing duration. Gum chewing habits were similar in males and females. A multivariate model demonstrated that only days per week chewing gum (p < 0.001) and gender (p = 0.007) were predictive of unstimulated salivary flow rate (R(2) = 0.40). Mean caries severity scores, assessed via ICDAS II and DMFT, increased with age. In multivariate analysis, age was positively associated with ICDAS (p = 0.001) and days per week chewing gum was negatively associated with ICDAS (p = 0.004), indicating that caries severity increased with age, and that days of chewing provided an inverse effect, with increased days of chewing being associated with decreased severity of caries. Overall, a history of frequent gum chewing is associated with higher unstimulated salivary flow rate and lower caries severity.

Oral health attitudes and behaviours of final-year dental students.

OBJECTIVES: The objectives of this study of final-year dental students in 10 classes (1997, 2001-2009) were to examine their self-reported oral health attitudes and behaviours and describe any trends in these attributes. PARTICIPANTS AND METHODS: Students were surveyed in final semester via an anonymous questionnaire (34 behaviour questions; eight attitude statements). Distributions, trends over time and attitude-behaviour associations were examined. RESULTS: Of 583 students, 459 responded (79%). All tooth-brushed with fluoride toothpaste; 80% brushed ≥2/day. Overall, 85% flossed; over time flossing behaviour increased significantly (P < 0.05), and those flossing 1-2/day increased (P < 0.005). Over time, significant decreases occurred in those taught toothbrushing (P < 0.001) and flossing (P < 0.05), and in use of mouth rinses (P < 0.05) and tooth cleansing sticks/picks (P < 0.001). Almost all (96%) had received a dental examination; 77% attended a dentist 1-3/year. Between-meal snacking was common (84%); 71% chewed gum. Although 18% had ever smoked, 5% currently smoked. Most strongly agreed they expected to keep most of their teeth for all their life (76%); their future needs for fillings would be minimal (61%); smoking could adversely affect their teeth or gums (85%); and regular dental attendance was important for their dental health (51%). Congruent attitudes and behaviours favouring oral health were widely held concerning dental attendance, flossing and smoking. CONCLUSIONS: Final-year dental students showed well established, favourable oral hygiene attitudes and behaviours, with evidence to suggest this knowledge was developed whilst in dental school. Despite many ceasing smoking, 5% still smoked. All dental students should receive training in motivational counselling and tobacco cessation to ensure this is included in patient care.

[Chewing gum as an additional agent in maintaining oral hygiene versus smoking status--preliminary study]. / Guma do zucia jako srodek dodatkowy w utrzymaniu higieny jamy ustnej a status palenia--badanie wstepne.

Nowadays chewing gum is widely used in different age groups, so complying with proper duration and frequency of chewing is an important factor influencing the state of masticatory system. The study involved 112 dental students of the Medical University of Lublin. Everyday use of chewing gum declared 47,32% of cases. Chewing time up to 10 minutes was stated in 23,08% of respondents, 11-20 minutes in 40,38% of interviewees. Among the examined students 17,3% smoked cigarettes. In smokers group 83,33% of questioned chewed the gum every day, while among non-smokers - 43,37%. Chewing time shorter than 10 minutes declared 22,22% of smokers and 23,26% of non-smokers, while chewing time between 11-20 minutes - 27,78% i 44,35% of smokers and non-smokers respectively. Obtained results indicate the need of carrying out further studies aimed at the nicotine influence on saliva parameters with respect to development of diseases of hard tooth tissues.

Dental erosion and its association with diet in Libyan schoolchildren.

AIM: To investigate any association between dental erosion and its potential dietary risk factors in a group of schoolchildren in Benghazi, Libya. STUDY DESIGN: A cross-sectional observational study. METHODS: A random sample of 12-year-old schoolchildren in 36 randomly selected schools completed a questionnaire to provide dietary data and underwent dental examination. Dental erosion was assessed using UK National Diet and Nutrition Survey (2000) criteria. Associations between erosion and dietary variables under study were investigated through processes of bivariate and multivariate analyses. RESULTS: Of 791 schoolchildren dentally examined, 40.8% had dental erosion; erosion into enamel affecting 32.5%, into dentine affecting 8% and into pulp affecting 0.3% of subjects. Bivariate analysis showed frequency of fruit-based sugary drink intake was statistically significantly and positively associated with erosion (p=0.006, Odds Ratio; 1.498, 95% CI; 1.124, 1.996) as was the length of time taken to consume acidic drinks (p≠0.005, Odds Ratio; 1.593, 95%CI; 1.161, 2.186). Additionally, multivariate analysis showed frequency of consumption of fruit other than bananas, sugared tea with milk and flavoured milk to also be positively associated with erosion (p=<0.05). CONCLUSIONS: In this group of Libyan 12-year-olds, frequency of consumption of fruit-based sugary drinks and length of time taken to consume acidic drinks were the primary statistically significant positive risk factors for dental erosion.

Use of nicotine replacement therapy for smoking reduction and during enforced temporary abstinence: a national survey of English smokers.

AIMS: To assess the prevalence of nicotine replacement therapy (NRT) use for smoking reduction (SR) and temporary abstinence (TA), the association between the two and the strength of the association between NRT use for SR or TA and socio-demographic characteristics, cigarette consumption and past quit attempts. DESIGN: Cross-sectional monthly surveys. SETTING: England. PARTICIPANTS: A total of 11, 414 smokers. MEASUREMENTS: Participants were asked (i) whether they were reducing the amount they smoked: if so, whether they used NRT; and (ii) whether they used NRT for TA. Demographic characteristics, daily cigarette consumption and whether a quit attempt had been made in the past 12 months were also assessed. FINDINGS: Of the participants, 56% were attempting SR, 14% were using NRT for SR and 14% were using NRT for TA. Use of NRT for SR and TA were highly correlated. The nicotine patch was the most commonly used form of NRT. The use of NRT for SR, compared with unassisted SR, was more common among older smokers, while the use of NRT for TA was more common among women. Cigarette consumption was higher in those using NRT for SR than those attempting SR without NRT. The use of NRT for SR and TA was associated positively with past quit attempts. CONCLUSIONS: Nicotine replacement therapy use for smoking reduction and temporary abstinence is common in England. The use of NRT for SR and TA does not appear to be associated with lower cigarette consumption relative to SR or TA without NRT, but is associated with a higher rate of past quit attempts.

[Oral hygiene habits among tobacco-smoking and non-smoking students of the Medical University of Lublin--chosen aspects]. / Nawyki dotyczace higieny jamy ustnej wsród palacych tyton i niepalacych studentów Uniwersytetu Medycznego w Lublinie--wybrane aspekty.

Among several etiologic factors for dental caries and periodontal diseases we can find dental plaque that forms on the teeth surfaces and prosthetic appliances. Elimination of dental plaque by proper oral hygiene procedures is crucial in caries and periodontal disease prevention. The aim of the study was evaluation of tobacco smoking prevalence among dental students of the Medical University of Lublin and the comparative analysis of oral hygiene habits among smoking and nonsmoking students. A questionnaire survey was carried out among 112 students of the Medical University of Lublin during the second, third, fourth and fifth year of their studies. The students were 20-28 years of age. The questions concerned cigarettes smoking habit and the ways of maintaining oral hygiene. Respondents were divided into smoking and non-smoking group. Statistical analysis was carried out. Obtained results were sent to statistical analysis. Cigarette smoking was reported by 16.67% of surveyed students. No significant differences between smoking and non-smoking students were stated in frequency of brushing, changing the toothbrush, density of toothbrush filaments, using manual and power toothbrush, using whitening toothpastes and frequency of using dental floss and toothpicks. Statistically significant difference was noted in gum chewing habit--smoking students chewed the gum more frequently (83.33%) than non-smoking students (40%). Significant differences occurred also in frequency of professional removal of dental deposits. Calculus removal performed twice a year was reported by 50% of smoking students, comparing with 17.8% of nonsmoking students. 37.78% of nonsmoking students declared professional teeth cleaning performed more often than twice a year comparing with 11.11% of respondents from the smokers group (p < 0.05).

Smoking cessation aids and strategies among former smokers in Canada.

OBJECTIVES: There is a need to better understand the prevalence of use of pharmaceutical aids among former smokers, and explore concerns that those former smokers may have had about using such products. This paper examines the use of various cessation aids and strategies as well as reasons for not using cessation aids among a nationally representative sample of former smokers from Canada. METHODS: Using data from the 2006 Canadian Tobacco Use Monitoring Survey (CTUMS), univariate analyses were performed to examine the use of different cessation aids, strategies to quit smoking, and reasons for not using cessation aids among former smokers who had quit in the previous two years. RESULTS: In 2006, over one in four Canadians (27.1% or about 7.2 million persons) aged 15 and older was a former smoker. Overall, female former smokers were more likely to report that they reduced their consumption of cigarettes as a quitting strategy, whereas male former smokers were more likely to report using a pharmacological aids when quitting. Among reasons given for not using cessation aids, lack of trust that these products would work was the most common (15.4%), following by issue of cost (8.5%), concern about possible side effects (5.8%) and lack of information about products (1.8%). CONCLUSION: These results suggest that men and women use different approaches to quit smoking. Our findings provide new insight which could be used to target cessation programs to the individuals where they are most likely to be effective.

Oral hygiene practices, dental knowledge, dietary habits and their relation to caries among male primary school children in Al Hassa, Saudi Arabia.

OBJECTIVES: To assess the frequency of consumption of cariogenic foods, oral hygiene practices and dental health knowledge among Saudi male primary school children in relation to socio-demographics and to find the possible predictors for dental caries among them. SUBJECTS AND METHODS: The cross-sectional descriptive study included 1115 Saudi male selected by multistage random sample from 18 public primary schools. Subjects were interviewed by closed ended questionnaire gathering data regarding frequency consumption of some cariogenic foods, oral hygiene practices and dental health knowledge. Students were submitted to dental screening to detect the clinically evident caries lesion. RESULTS: The clinically decayed tooth was diagnosed in 68.9% of the included children, more in urban and younger students. Caries affected the subjects consumed cariogenic foods at greater frequency compared with caries-free children. Only 24.5% of the students brushed their teeth twice or more per day, and 29% of them never received instructions regarding oral hygiene practices. Miswak as an alternative and/or additional method of dental cleaning was used by 44.6%. Stepwise logistic regression analysis revealed that maternal working conditions, large family size and poor oral hygiene practices were the chief predictors for dental caries among the included school children. CONCLUSION: The poor oral hygiene practices, lack of parental guidance and appropriate dental health knowledge with frequent exposure to cariogenic foods in addition to socio-demographics are the main risk factors for dental decay among the surveyed students.

Scalp hair and urine mercury content of children in the Northeast United States: the New England Children's Amalgam Trial.

UNLABELLED: Children may be at particular risk from toxic effects of mercury (Hg). Previous studies of hair (organic) and urine (inorganic) Hg levels in US children were unable to assess Hg levels while accounting for exposure to amalgam dental restorations. This analysis describes, over a 5-year period, levels and correlates/predictors of scalp hair (H-Hg) and urinary (U-Hg) mercury in 534 New England Children's Amalgam Trial (NECAT) participants, aged 6-10 years and without exposure to dental amalgam at baseline. RESULTS: Mean H-Hg levels were between 0.3 and 0.4 microg/g over 5 years. 17-29% of children had H-Hg levels > or = 0.5 microg/g, and 5.0 to 8.5% of children had levels > or = 1 microg/g, in any given study year. In adjusted models, fish consumption frequency was the most robust predictor of high H-Hg. U-Hg mean levels were between 0.7 and 0.9 microg/g creatinine over two years. The percentage of those with U-Hg > or 2.3 microg/g creatinine ranged from 4% to 6%. Number of amalgam restorations had a significant dose-response relationship with U-Hg level. Daily gum chewing in the presence of amalgam was associated with high U-Hg.

Prevalence of OME is reduced in young children using chewing gum.

OBJECTIVE: The present study investigates a possible relationship between use of chewing gum and otitis media with effusion (OME) in children. Chewing obviously activates jaw movements, increases salivary flow, and, by the way, the rate of swallowing and the rate of activations of peritubal muscles and tubal openings. Chewing also requires nasal respiration, thus preventing mouth breathing. DESIGN: Cross-sectional study: 1756 children (2 to 6 yr of age), apparently in good health and visiting different Dutch child health centers in the region of Utrecht were examined between September 1999 and April 2002. OME was diagnosed by combined tympanometry and otoscopy. The criterion for OME was unilateral or bilateral type B tympanogram, according to Jerger. The parents had to fill out a questionnaire with a question pertaining to the chewing habits of their child. RESULTS: Logistic regression points out that age and season as well as chewing gum-consuming habits significantly influence the prevalence of OME. The strongest effects are age (OME becomes less frequent with age) and season (OME occurs less when climate is more favorable), but -- ceteris paribus -- a child consuming daily or at least weekly chewing gum shows significantly less chance for OME than a child who seldom consumes or consumes no chewing gum (p = 0.023). CONCLUSIONS: In the case of regular use of chewing gum, the probability of having OME in children is reduced by 40%. It seems plausible that children with immature oral motorics do not like chewing gum.

Gender differences in associations between occlusal support and signs of temporomandibular disorders: results of the population-based Study of Health in Pomerania (SHIP).

PURPOSE: The aim of this study was to investigate whether gender-dependent associations exist between signs of temporomandibular disorders (TMD) and occlusal support. MATERIALS AND METHODS: Stratified by gender, the data of 2,963 35- to 74-year-old participants from the epidemiologic Study of Health in Pomerania were used in logistic regression analyses with temporomandibular joint (TMJ) tenderness and muscle tenderness as the dependent variables. Occlusal support was classified according to the Eichner index, a classification system based on occluding pairs of teeth. The final model was adjusted for bruxism, age, and various sociodemographic data. RESULTS: Logistic regression analyses revealed increased odds ratios for TMJ tenderness in men with loss of all four molar and premolar supporting zones (odds ratio 3:9) and without antagonist contact (odds ratio 2:7). Significant relationships in men were also found between muscle tenderness and loss of one (odds ratio 2:1), three (odds ratio 2:1), or four supporting zones (odds ratio 2:7), and loss of any tooth contact (odds ratio 2:3). In women, significant associations between occlusal support and TMD signs were absent. Subjects with bruxism were more likely to have TMJ tenderness (odds ratio women 2:0, men 1:9). In women, an additional relationship existed between bruxism and muscle tenderness (odds ratio 1:7). The following habits showed no significance: gum chewing, unilateral chewing, and lip/tongue/cheek biting. CONCLUSION: Only in men was the loss of occlusal support significantly associated with muscle and TMJ tenderness. The association between bruxism and TMD signs supports the theory that repetitive adverse loading of the masticatory system may cause functional disturbances.

Chewing gum differentially affects aspects of attention in healthy subjects.

In a study published previously in this journal (Wilkinson et al., 2002), the effect of chewing gum on cognitive functioning was examined. The results of this study indicated that chewing a piece of gum results in an improvement of working memory and of both immediate and delayed recall of words but not of attention. In the present study, memory and a variety of attentional functions of healthy adult participants were examined under four different conditions: no chewing, mimicking chewing movements, chewing a piece of tasteless chewing gum and chewing a piece of spearmint flavoured chewing gum. The sequence of conditions was randomised across participants. The results showed that the chewing of gum did not improve participants' memory functions. Furthermore, chewing may differentially affect specific aspects of attention. While sustained attention was improved by the chewing of gum, alertness and flexibility were adversely affected by chewing. In conclusion, claims that the chewing a gum improves cognition should be viewed with caution.