Fluoride and sodium trimetaphosphate (TMP) release from fluoride varnishes supplemented with TMP.

This study assessed fluoride (F) and sodium trimetaphosphate (TMP) release into artificial saliva from varnishes containing 0%, 2.5%, and 5% NaF, supplemented or not with 5% TMP. The varnishes were applied on polyester sheets (n = 8/group), and F and TMP released into artificial saliva were measured for up to 24 hours. The amount of F and TMP released were directly related to NaF and TMP concentrations in the varnishes. The highest F release was seen for 5% NaF and 5% NaF + 5% TMP, whereas 5% TMP released the highest amount of TMP. However, the simultaneous addition of NaF and TMP to varnishes significantly reduced the amount of F and TMP released from the products.

Effects of pH and fluoride concentration of dentifrices on fluoride levels in saliva, biofilm, and biofilm fluid in vivo.

INTRODUCTION: Acidic dentifrices have been shown to be more effective than neutral ones against dental caries using in vitro, in situ, and clinical protocols. OBJECTIVES: Given the scarcity of studies assessing intraoral fluoride (F) retention after using such formulations, the present study evaluated the influence of pH and F concentration of dentifrices on F uptake by saliva, biofilm, and biofilm fluid. METHODS: Volunteers (n = 22) were randomly assigned to dentifrices containing 0 (placebo), 550 (LFD, low-fluoride dentifrice), and 1100 ppm F (CD, conventional dentifrice) at pH 4.5 and 7.0 and brushed their teeth 3 times/day following a double-blind, crossover protocol. Saliva and biofilm samples were collected after 7 days of using the dentifrices, 1 and approximately 12 h after last brushing. F and calcium (Ca) analyses were performed with the inverted electrode after buffering with TISAB III and the Arsenazo III method, respectively. Data were analyzed by 3-way ANOVA, Tukey's HSD test, and Pearson's correlation coefficient (p < 0.05). RESULTS: F concentrations in biofilm fluid and whole biofilm 1 h after brushing with acidic F-toothpastes were higher than those related to neutral counterparts, although the differences were small and not significant; no increases were observed in salivary F concentrations influenced by dentifrice pH. Moreover, no definite trend was observed for Ca concentrations in these compartments. CONCLUSION: Dentifrice pH had some influence on F uptake by the biofilm fluid, having lesser or no impact on F uptake by the biofilm and saliva, respectively. CLINICAL SIGNIFICANCE: Toothbrushing with acidic toothpastes leads to slight increases in F concentrations in the biofilm fluid when compared to neutral formulations, which may contribute to the higher anticaries effect of acidic formulations.

Effects of polyphosphates and fluoride on hydroxyapatite dissolution: A pH-stat investigation.

OBJECTIVES: This study investigated the immediate and sustained effect of sodium trimetaphosphate (TMP) and sodium hexametaphosphate (HMP) associated or not with fluoride (F) on hydroxyapatite (HA) dissolution using an erosion-like model, considering as well as the influence of salivary coating. DESIGN: Baseline dissolution rates were determined for HA discs using a pH-stat system. In the first set of experiments, HA discs were treated with 1100µgF/mL, 1% or 8% of HMP, 1% or 8% of TMP and 1100µgF/mL associated with 1% or 8% of HMP or TMP, totaling 9 groups (n=8). In a second phase, HA discs were kept in pooled human saliva at 37°C for 2h before treatment with deionised water and 1100µgF/mL associated with 1% or 8% of HMP or TMP, totaling 5 groups (n=8). The post-treatment dissolution rate was determined from three consecutive 30-min assays. Data were analysed using 2 and 3-way ANOVA followed by Fisher and Holm-Sidak methods, respectively (α=0.05). RESULTS: All test solutions promoted reduction in HA dissolution rate when compared to baseline control in the first post-treatment run (p<0.001). However, a synergistic effect was only observed between fluoride and 1% HMP. Moreover, the duration of inhibitory effect was greater when 8% HMP and 1 or 8% HMP associated with F were assessed (p<0.001). The presence of salivary coating led to higher protection for all groups when compared to discs without coating (p<0.001). CONCLUSION: The reduction of HA dissolution rate, as well as the duration of this effect were influenced by fluoride, type and concentration of phosphate salt and the presence of a salivary coating.

Fluoride and sodium trimetaphosphate (TMP) release from fluoride varnishes supplemented with TMP

Abstract This study assessed fluoride (F) and sodium trimetaphosphate (TMP) release into artificial saliva from varnishes containing 0%, 2.5%, and 5% NaF, supplemented or not with 5% TMP. The varnishes were applied on polyester sheets (n = 8/group), and F and TMP released into artificial saliva were measured for up to 24 hours. The amount of F and TMP released were directly related to NaF and TMP concentrations in the varnishes. The highest F release was seen for 5% NaF and 5% NaF + 5% TMP, whereas 5% TMP released the highest amount of TMP. However, the simultaneous addition of NaF and TMP to varnishes significantly reduced the amount of F and TMP released from the products.

Efeito de vernizes fluoretados suplementados com trimetafosfato de sódio na desmineralização e remineralização do esmalte bovino: estudos in vitro e in situ / Effect of fluoride varnishes supplemented with sodium trimetaphosphate on the demineralization and reminieralization of bovine tooth enamel: in vitro and in situ studies

O objetivo do presente estudo foi avaliar o efeito de vernizes fluoretados suplementados com Trimetafosfato de Sódio (TMP) sobre a desmineralização e remineralização do esmalte dentário. Para tanto, o estudo foi dividido em 4 capítulos. Inicialmente foi avaliada a liberação de fluoreto (F) e fosfato (P) em soluções de saliva artificial (24 h) após aplicação de vernizes contendo 2,5% NaF, 5% NaF, 5% TMP, 2,5% NaF/5% TMP, 5% NaF/5% TMP, além de uma formulação placebo (sem NaF e TMP) e um verniz comercial (Duraphat), descrito no Capítulo 1. Os efeitos destes vernizes sobre a remineralização de lesões de cárie artificial, bem como sobre a desmineralização do esmalte hígido foram avaliados, respectivamente, nos Capítulos 2 e 3, em modelos de ciclagem de pH. Por fim, o potencial remineralizador dos vernizes placebo, 5% NaF e 5% NaF/5% TMP foi avaliado em um protocolo in situ (Capítulo 4). Os espécimes foram avaliados quanto a dureza de superfície (SH), porcentagem de recuperação de SH (%SHR), dureza em secção longitudinal (ΔKHN), microscopia de luz polarizada, bem como a quantidade de CaF2 e fluoreto fortemente ligado ao esmalte. Uma relação dose-resposta entre a quantidade de NaF e TMP nos vernizes e a liberação de F e P nas soluções de saliva artificial foi observada. Embora um efeito inibitório parcial na liberação de F e P tenha sido observado na presença dos dois sais, um efeito sinérgico foi observado na %SHR e ΔKHN na remineralização de lesões de cárie, bem como na redução da desmineralização (SH e ΔKHN) do esmalte hígido para vernizes contendo NaF e TMP. Em ambas as situações, o efeito protetor do verniz contendo 5% NaF/5% TMP foi significativamente maior que os demais grupos in vitro. Este padrão foi confirmado em um protocolo in situ sobre a remineralização do esmalte cariado. A formação de CaF2 e incorporação de fluoreto no esmalte foi, contraditoriamente, menor para vernizes contendo TMP em comparação aos vernizes contendo mesma concentração de F...

The aim of the study was to assess the effects of fluoridated varnishes supplemented with sodium trimetaphosphate (TMP) on enamel demineralization and remineralization. For this purpose, the study was divided into 4 chapters. First, the amount of fluoride (F) and phosphate (P) released in artificial saliva solutions (24 h) were measured after the application of varnishes containing 2.5% NaF, 5% NaF, 5% TMP, 2.5% NaF/5% TMP, 5% NaF/5% TMP, besides a PLACEBO formulation (no NaF or TMP) and a commercial formulation (Duraphat), as described in Chapter 1. The effects of these varnishes on the remineralization of caries-like lesions, as well as on the demineralization of sound enamel were assessed on Chapters 2 and 3, respectively, using pH-cycling models. Finally, the remineralizing effect of PLACEBO, 5% NaF and 5% NaF/5% TMP was evaluated using and in situ protocol (Chapter 4). Specimens were analyzed by surface hardness (SH), percentage of SH recovery (%SHR), cross-sectional hardness (ΔKHN), polarized light microscopy, as well as firmly and loosely (CaF2) bound fluoride. A dose-response relationship was observed between NaF and TMP concentrations in the formulations and the amount of F and P released into artificial saliva. Although a partial inhibitory effect on F and P release was observed in the presence of the two salts, a synergistic effect was observed in %SHR and ΔKHN on the remineralization of caries-like lesions, as well as on the reduction of sound enamel demineralization (SH e ΔKHN) for varnishes containing NaF e TMP. Under both conditions, the protective effect of the 5% NaF/5% TMP varnish was significantly higher than the other groups in vitro. The same pattern was confirmed in situ on the remineralization carious enamel. Firmly and loosely bound fluoride were contradictorily lower for varnishes containing TMP when compared with their counterparts without TMP. Based on the above, it was concluded that TMP-supplemented fluoride varnishes were able...

Efeito de vernizes fluoretados suplementados com trimetafosfato de sódio na desmineralização e remineralização do esmalte bovino: estudos in vitro e in situ / Effect of fluoride varnishes supplemented with sodium trimetaphosphate on the demineralization and reminieralization of bovine tooth enamel: in vitro and in situ studies

O objetivo do presente estudo foi avaliar o efeito de vernizes fluoretados suplementados com Trimetafosfato de Sódio (TMP) sobre a desmineralização e remineralização do esmalte dentário. Para tanto, o estudo foi dividido em 4 capítulos. Inicialmente foi avaliada a liberação de fluoreto (F) e fosfato (P) em soluções de saliva artificial (24 h) após aplicação de vernizes contendo 2,5% NaF, 5% NaF, 5% TMP, 2,5% NaF/5% TMP, 5% NaF/5% TMP, além de uma formulação placebo (sem NaF e TMP) e um verniz comercial (Duraphat), descrito no Capítulo 1. Os efeitos destes vernizes sobre a remineralização de lesões de cárie artificial, bem como sobre a desmineralização do esmalte hígido foram avaliados, respectivamente, nos Capítulos 2 e 3, em modelos de ciclagem de pH. Por fim, o potencial remineralizador dos vernizes placebo, 5% NaF e 5% NaF/5% TMP foi avaliado em um protocolo in situ (Capítulo 4). Os espécimes foram avaliados quanto a dureza de superfície (SH), porcentagem de recuperação de SH (%SHR), dureza em secção longitudinal (ΔKHN), microscopia de luz polarizada, bem como a quantidade de CaF2 e fluoreto fortemente ligado ao esmalte. Uma relação dose-resposta entre a quantidade de NaF e TMP nos vernizes e a liberação de F e P nas soluções de saliva artificial foi observada. Embora um efeito inibitório parcial na liberação de F e P tenha sido observado na presença dos dois sais, um efeito sinérgico foi observado na %SHR e ΔKHN na remineralização de lesões de cárie, bem como na redução da desmineralização (SH e ΔKHN) do esmalte hígido para vernizes contendo NaF e TMP. Em ambas as situações, o efeito protetor do verniz contendo 5% NaF/5% TMP foi significativamente maior que os demais grupos in vitro. Este padrão foi confirmado em um protocolo in situ sobre a remineralização do esmalte cariado. A formação de CaF2 e incorporação de fluoreto no esmalte foi, contraditoriamente, menor para vernizes contendo TMP em comparação aos vernizes contendo mesma concentração de F, sem...

The aim of the study was to assess the effects of fluoridated varnishes supplemented with sodium trimetaphosphate (TMP) on enamel demineralization and remineralization. For this purpose, the study was divided into 4 chapters. First, the amount of fluoride (F) and phosphate (P) released in artificial saliva solutions (24 h) were measured after the application of varnishes containing 2.5% NaF, 5% NaF, 5% TMP, 2.5% NaF/5% TMP, 5% NaF/5% TMP, besides a PLACEBO formulation (no NaF or TMP) and a commercial formulation (Duraphat), as described in Chapter 1. The effects of these varnishes on the remineralization of caries-like lesions, as well as on the demineralization of sound enamel were assessed on Chapters 2 and 3, respectively, using pH-cycling models. Finally, the remineralizing effect of PLACEBO, 5% NaF and 5% NaF/5% TMP was evaluated using and in situ protocol (Chapter 4). Specimens were analyzed by surface hardness (SH), percentage of SH recovery (%SHR), cross-sectional hardness (ΔKHN), polarized light microscopy, as well as firmly and loosely (CaF2) bound fluoride. A dose-response relationship was observed between NaF and TMP concentrations in the formulations and the amount of F and P released into artificial saliva. Although a partial inhibitory effect on F and P release was observed in the presence of the two salts, a synergistic effect was observed in %SHR and ΔKHN on the remineralization of caries-like lesions, as well as on the reduction of sound enamel demineralization (SH e ΔKHN) for varnishes containing NaF e TMP. Under both conditions, the protective effect of the 5% NaF/5% TMP varnish was significantly higher than the other groups in vitro. The same pattern was confirmed in situ on the remineralization carious enamel. Firmly and loosely bound fluoride were contradictorily lower for varnishes containing TMP when compared with their counterparts without TMP. Based on the above, it was concluded that TMP-supplemented fluoride varnishes were able...

Effect of fluoride varnish supplemented with sodium trimetaphosphate on enamel erosion and abrasion.

PURPOSE: To assess in vitro the effect on enamel erosion (ERO) and erosion followed by abrasion (ERO+ABR) of varnishes with different fluoride concentrations, supplemented or not with sodium trimetaphosphate (TMP). METHODS: Bovine enamel blocks were randomly divided into six groups according to the type of varnish used: placebo (no F), NaF 5%, NaF 2.5%, NaF 2.5% plus TMP 3.5%, NaF 2.5% plus TMP 5%, NaF 2.5% plus TMP 10%. Varnishes were tested for ERO and ERO+ABR, separately for 3 and 5 days. ERO was done by immersion in Sprite Zero (5 minutes, 4x/day), while ERO+ABR was performed by brushing for 15 seconds after each erosive challenge. Enamel wear (microm) and cross-sectional hardness (AKHN) were assessed after the experimental periods. Data were analyzed by ANOVA, Tukey's test and Pearson's correlation coefficient (P< 0.05). RESULTS: Varnishes supplemented with TMP promoted significantly lower wear and hardness loss when compared to the other treatments in all conditions studied (P< 0.05). Similar wear rates were observed for the placebo, NaF 2.5% and NaF 5% varnishes (P> 0.05). Greater wear was observed after 5 days of ERO and ERO+ABR when compared with 3 days (P< 0.05). Positive and significant correlations were found between enamel wear and AKHN. No dose-response relationship was found between TMP concentration and wear and hardness. It was concluded that fluoride varnishes supplemented with TMP had a higher protective effect against ERO and ERO+ABR, which was associated with a reduction in enamel softening.

Plaque fluoride concentrations associated to the use of conventional and low-fluoride dentifrices.

PURPOSE: This double-blind, crossover study evaluated whole plaque fluoride concentration (F), as well as whole plaque calcium concentrations (Ca) after brushing with a placebo (PD - fluoride free), low-fluoride (LFD, 513 microg F/g) and conventional (CD, 1,072 microg F/g) dentifrices. METHODS: Children (n=20) were randomly assigned to brush twice daily with one of the dentifrices, during 7 days. On the 7th day, samples were collected at 1 and 12 hours after brushing. F and Ca were analyzed with an ion-selective electrode and with the Arsenazo III method, respectively. Data were analyzed by ANOVA, Tukey's test and by Pearson correlation coefficient (P< 0.05). RESULTS: The use of the fluoridated dentifrices significantly increased plaque [F]s 1 hour after brushing when compared to PD, returning to baseline levels 12 hours after. Positive and significant correlations were found between plaque [F] and (Ca) under most of the conditions evaluated. The mean increase in plaque [F] observed 1 hour after brushing with the CD were only about 47% higher than those obtained for the LFD. The use of a LFD promotes proportionally higher increases in plaque [F] when compared to a CD. Plaque F concentrations were also shown to be dependent on plaque Ca concentrations.

Fluoride concentration of some brands of fermented milks available in the market.

OBJECTIVES: To evaluate the fluoride ion concentration in some fermented milks present in the market. METHODS: Three brands of 6 fermented milks (Parmalat®-uva, Chamyto®, Paulista®, Batavito®, Yakult®, Vigor Club®) were analyzed. Fluoride concentration was evaluated after facilitated microdiffusion by HDMS. RESULTS: Parmalat® products ranged from 0.022 µgF/g to 0.031 µgF/g, Chamyto® from 0.228 µgF/g to 0.272 µgF/g, Paulista® from 0.182 µgF/g to 0.220 µgF/g, Batavito® from 0.028 µgF/g to 0.030 µgF/g, Yakult® from 0.115 µgF/g to 0.206 µgF/g and Vigor Club® from 0.808 µgF/g to 1.171 µgF/g. CONCLUSIONS: The presence of fluoride could be observed in all of the fermented milks analyzed which can contribute with the total fluoride daily intake.

Efeito do uso de vernizes com alta e baixa concentração de fluoreto suplementado com trimetafosfato sobre a erosão e abrasão do esmalte dentário: estudo in vitro / Effect of the use of varnish with high and low concentration of fluoride supplemented with trimetaphosphate on the erosion and abrasion of the dental enamel

A proposta deste trabalho foi avaliar in vitro a ação de vernizes com diferentes concentrações de fluoretos e suplementado com trimetafosfato de sódio (TMP) sobre a erosão associada ou não à abrasão. Blocos de esmalte bovino foram selecionados e divididos em 12 grupos de acordo com o número de dias de tratamento (3 e 5 dias) e o tipo de verniz utilizado: placebo (sem flúor), NaF 5%, NaF 2,5%, NaF 2,5% TMP 3,5%, NaF 2,5% TMP 5%, NaF 2,5% TMP 10%. O desafio erosivo foi produzido com Sprite Zero® por 5 minutos (4x ao dia) e o erosivo/abrasivo pela escovação mecânica por 15 segundos. Após os desafios, determinou-se a dureza de superfície (SHf), o desgaste do esmalte (μm) e a dureza em secção longitudinal (KHN). Os resultados foram submetidos a Análise de Variância e ao teste de Tukey (p<0,05). Os vernizes com 2,5% de fluoreto e TMP(3,5; 5 e 10%) apresentaram os menores desgaste e perda de dureza (KHN) do que os outros vernizes (p<0,05), independente do desafio. Observou-se correlação positiva entre os resultados de desgaste e KHN. Não houve relação dose-resposta entre a concentração do TMP e o desgaste e a dureza. Maiores desgaste foram observados com 5 dias de experimento e maiores valores de SHf com o desafio erosivo/abrasivo. Os vernizes placebo, NaF 2,5% e NaF 5% apresentaram desgastes similares (p>0,05). Concluiu-se que os vernizes fluoretados suplementados com TMP apresentaram maior efeito contra a erosão e erosão/abrasão do esmalte e menor amolecimentos do esmalte

The purpose of this study was to evaluate in vitro the action of varnishes with different concentrations of fluoride and supplemented with trimetaphosphate (TMP) on erosion with or without abrasion. Bovine enamel blocks were selected and divided into 12 groups according to the number of treatment days (3 and 5 days) and type of varnish used: placebo (no fluoride), NaF 5%, NaF 2.5%, NaF 2.5% TMP 3.5%, NaF 2.5% TMP 5%, NaF 2.5% TMP 10%. The erosive challenge was made with Sprite Zero ® for 5 minutes (4x daily) and erosive / abrasive by mechanical brushing for 15 seconds. After the challenges, we determined the surface hardness (SHf), the enamel wear (ìm) in longitudinal section and hardness ( KHN). The results were submitted to ANOVA and Tukey test (p<0.05). The varnish fluoride and 2.5% TMP (3.5, 5 and 10%) showed the lowest wear loss and hardness ( KHN) than other coatings (p <0.05), regardless of the challenge. We observed a positive correlation between the results of wear and KHN. There was no dose-response relationship between the concentration of TMP and the wear and hardness. Greater wear was observed with 5 days of experiment and higher values of SHf with the challenge erosive / abrasive. The placebo varnish, NaF 2.5% and NaF 5% showed similar wear (p> 0.05). It was concluded that fluoride varnish supplemented with TMP had higher effect against erosion and erosion / abrasion of enamel and less softening of the enamel

Evaluation of fermented milk containing probiotic on dental enamel and biofilm: in situ study.

OBJECTIVES: The aim of this study was to in situ evaluate the pH before and after the application of the fermented milk product; the fluoride (F), calcium (Ca), phosphate (P), and insoluble extracellular polysaccharides (EPS) concentration on the dental biofilm; the demineralisation of the bovine dental enamel. DESIGN: Ten volunteers wore palatine devices containing four blocks of bovine dental enamel during three phases of 14 days each. In each phase, the treatment was accomplished with either fermented milk A (Yakult), or 20% sucrose solution (control) or fermented milk B (Batavito). Then, dental biofilm was collected, processed and the ionic concentration and insoluble extracellular polysaccharides appraised. For evaluation of the mineral loss, both the initial and final microhardness were determined. RESULTS: The results showed that the ionic concentration (F, Ca and P) was significantly higher in the fermented milk B in comparison with both the fermented milk A and the 20% sucrose solution. There was no significant difference amongst these last two. With regarding EPS was significantly lower in fermented milk B compared to fermented milk A and sucrose (P<0.05), without significant difference amongst these last two. The two experimental groups did not differ significantly but had smaller mineral losses than control group. CONCLUSION: It was concluded that all treatment decreased the pH of dental biofilm and promoted demineralisation of the enamel, although fermented milk B presented the lowest EPS content and percentage change and integrated loss of surface hardness. More studies should be developed to evaluate the action of probiotics on the bacterial activity and its interference on demineralisation, once the literature has been showing probiotics as a promissory caries reducing agent.

Evaluation of the limited participation by university students in a smoking cessation program.

OBJECTIVE: To evaluate the limited participation by university students in a smoking cessation program. METHODS: A cross-sectional, comparative study was conducted at the University of Caxias do Sul, located in Caxias do Sul, Brazil, involving students who enrolled in a smoking cessation program, together with those who did not. RESULTS: Of the 108 student who did not enroll in the program, 102 (94.4%) stated that they had no intention to quit smoking (95% confidence interval: 88.29-97.93%. Comparisons between the enrolled and nonenrolled students revealed the following statistical differences: in mean age (35 vs. 23 years, p < 0.01); mean duration of the smoking habit (19.42 vs. 7.36 years, p < 0.01); considering oneself addicted (100% vs. 58.5%, p = 0.047); believing oneself able to stop smoking at any time (7.1% vs. 22.6%, p = 0.02); having no knowledge of any reasons to quit smoking (37.5% vs. 12%, p = 0.03); having suffered discrimination (42.9% vs. 9.3%, p < 0.01). CONCLUSION: Among the university students evaluated, there was a phase, classified as precontemplative or contemplative, during which they were refractory to smoking cessation. Although all of the students were aware of the diseases caused by smoking, 41.5% did not consider themselves addicted. The concept of substance dependence does not apply to these students. It would seem more appropriate to define nicotine dependence as resulting from the lifetime consumption of at least 100 cigarettes. These students do not perceive that they are passing through the initial phase of the natural history of tobacco use disorder and do not realize that they are increasing their risk of presenting smoking-related diseases in the future.

Avaliação da participação de pequeno número de estudantes universitários em um programa de tratamento do tabagismo / Evaluation of the limited participation by university students in a smoking cessation program

OBJETIVO: Avaliar a participação de pequeno número de estudantes da Universidade de Caxias do Sul em um programa de tratamento do tabagismo. MÉTODOS: Delineamento transversal e comparativo entre alunos que se inscreveram em um programa de tratamento do tabagismo e alunos que não se inscreveram. RESULTADOS: De 108 alunos não inscritos, 102 não mostraram intenção de parar de fumar (94,4 por cento, intervalo de confiança de 95 por cento de 88,29 por cento a 97,93 por cento). As comparações entre inscritos e não inscritos mostraram diferenças estatísticas, respectivamente: nas idades 35 e 23 anos, p < 0,01; tempo de tabagismo em anos, 19,42 e 7,36, p < 0,01; considerarem-se viciados, 100 por cento e 58,5 por cento, p = 0,047; acreditarem que podem parar de fumar quando querem, 7,1 por cento e 22,6 por cento, p = 0,02; desconhecerem os motivos de fumar, 37,5 por cento e 12 por cento, p = 0,03; sofrerem discriminações, 42,9 por cento e 9,3 por cento, p < 0,01. CONCLUSÃO: Identificou-se, nos estudantes universitários, uma fase refratária ao abandono do vício, classificada como pré-contemplativa e contemplativa. Os alunos conheciam as doenças provocadas pelo cigarro, contudo 41,5 por cento deles não reconheciam ser viciados. O conceito de dependência de drogas não se aplica a esses estudantes. Parece mais adequado considerar dependência à nicotina a partir do consumo de 100 cigarros ao longo da vida. Outros fatos que passam despercebidos a esses alunos são que eles estão vivendo a primeira fase da história natural do tabagismo e que estão apostando em não ter doenças futuras.

OBJECTIVE: To evaluate the limited participation by university students in a smoking cessation program. METHODS: A cross-sectional, comparative study was conducted at the University of Caxias do Sul, located in Caxias do Sul, Brazil, involving students who enrolled in a smoking cessation program, together with those who did not. RESULTS: Of the 108 student who did not enroll in the program, 102 (94.4 percent) stated that they had no intention to quit smoking (95 percent confidence interval: 88.29-97.93 percent. Comparisons between the enrolled and nonenrolled students revealed the following statistical differences: in mean age (35 vs. 23 years, p < 0.01); mean duration of the smoking habit (19.42 vs. 7.36 years, p < 0.01); considering oneself addicted (100 percent vs. 58.5 percent, p = 0.047); believing oneself able to stop smoking at any time (7.1 percent vs. 22.6 percent, p = 0.02); having no knowledge of any reasons to quit smoking (37.5 percent vs. 12 percent, p = 0.03); having suffered discrimination (42.9 percent vs. 9.3 percent, p < 0.01). CONCLUSION: Among the university students evaluated, there was a phase, classified as precontemplative or contemplative, during which they were refractory to smoking cessation. Although all of the students were aware of the diseases caused by smoking, 41.5 percent did not consider themselves addicted. The concept of substance dependence does not apply to these students. It would seem more appropriate to define nicotine dependence as resulting from the lifetime consumption of at least 100 cigarettes. These students do not perceive that they are passing through the initial phase of the natural history of tobacco use disorder and do not realize that they are increasing their risk of presenting smoking-related diseases in the future.