The effect of aspartame and pH changes on the erosive potential of cola drinks in bovine enamel : an in vitro study

The aim of this study was to clarify the mechanism behind the different erosive potential of regular and light cola drinks: pH difference and/or aspartame presence. Sixty bovine enamel blocks were randomly divided into 5 groups: RC - regular cola, RCpH - addition of base to increase regular cola pH, RCAS - addition of aspartame to regular cola, LC - light cola, and LCpH - addition of acid to decrease light cola pH. Two-thirds of the blocks surface was coated with nail varnish for reference. The samples were daily subjected to four erosive challenges for 2 minutes. Between the erosive challenges (2h) and overnight the samples were maintained in artificial saliva. The response variable was the percentage surface hardness change (%SHC) after 1st experimental day and enamel surface loss (µm) measured at the 5th day by profilometry. Data were analyzed by ANOVA and Tukey?s test (p<0.05). Independently of the cola modifications, all groups promoted similar hardness change of enamel surface. RC promoted higher enamel loss (6.69±0.71µm) than LC (4.80±0.77µm). The acid addition to light cola (LCpH: 6.60±1.78µm) significantly enhanced its erosive potential, which did not differ from RC. The base addition to regular cola (RCpH-4.00±0.64µm) resulted in similar wear to LC. The addition of aspartame to the regular cola (RCAS 5.44±0.65µm) resulted in similar wear to LC and RC. The data suggest that the pH alteration has a major impact on the erosive potential of cola drinks, however, the sweetener also has some influence

Effect of vegetable oils applied over acquired enamel pellicle on initial erosion

Objective The prevalence of dental erosion has been recently increasing, requiring new preventive and therapeutic approaches. Vegetable oils have been studied in preventive dentistry because they come from a natural, edible, low-cost, and worldwide accessible source. This study aimed to evaluate the protective effect of different vegetable oils, applied in two concentrations, on initial enamel erosion. Material and Methods Initially, the acquired pellicle was formed in situ for 2 hours. Subsequently, the enamel blocks were treated in vitro according to the study group (n=12/per group): GP5 and GP100 – 5% and pure palm oil, respectively; GC5 and GC100 – 5% and pure coconut oil; GSa5 and GSa100 – 5% and pure safflower oil; GSu5 and GSu100 – 5% and pure sunflower oil; GO5 and GO100 – 5% and pure olive oil; CON− – Deionized Water (negative control) and CON+ – Commercial Mouthwash (Elmex® Erosion Protection Dental Rinse, GABA/positive control). Then, the enamel blocks were immersed in artificial saliva for 2 minutes and subjected to short-term acid exposure in 0.5% citric acid, pH 2.4, for 30 seconds, to promote enamel surface softening. The response variable was the percentage of surface hardness loss [((SHi - SHf) / SHf )×100]. Data were analyzed by one-way ANOVA and Tukey’s test (p;0.05) and less than the other groups (

Influence of mandibular and palatal intraoral appliances on erosion in situ study outcome

The standardization of in situ protocols for dental erosion is important to enable comparison between studies. Objective: Thus, the objectives of this study were to evaluate the influence of the location of in situ intraoral appliance (mandibular X palatal) on the extent of enamel loss induced by erosive challenges and to evaluate the comfort of the appliances. Material and Methods: One hundred and sixty bovine enamel blocks were selected according to their initial surface hardness and randomly divided into two groups: GI - palatal appliance and GII - mandibular appliance. Twenty volunteers wore simultaneously one palatal appliance (containing 4 enamel blocks) and two mandibular appliances (each one containing 2 enamel blocks). Four times per day during 5 days, the volunteers immersed their appliances in 0.01 M hydrochloric acid for 2 minutes, washed and reinserted them into the oral cavity for 2 hours until the next erosive challenge. After the end of the in situ phase, the volunteers answered a questionnaire regarding the comfort of the appliances. The loss of tissue in the enamel blocks was determined profilometrically. Data were statistically analyzed by paired t-test, Chi-square and Fisher's Exact Test (p&lt;0.05). Results: The enamel blocks allocated in palatal appliances (GI) presented significantly higher erosive wear when compared to the blocks fixed in mandibular appliances (GII). The volunteers reported more comfort when using the palatal appliance. Conclusions: Therefore, the palatal appliance is more comfortable and resulted in higher enamel loss compared to the mandibular one

Eroded enamel rehardening using two intraoral appliances designs in different times of salivary exposure

The aim of this study was evaluated the eroded enamel rehardening potential using upper palatal and lower buccal removable appliances in different times of salivary exposure (30 min, 1h, 2h, 12h) after a single erosive challenge event. After initial surface hardness evaluation, bovine enamel blocks were eroded in vitro (0.01 M hydrochloric acid, pH 2.3, 30 seconds), selected (n = 160) and randomly assigned to the two appliance designs and twenty volunteers. Four enamel blocks were inserted in each removable appliance. On the in situ phase, the volunteers were instructed to use the upper palatal and lower buccal appliances simultaneously for 12 nonconsecutive hours. After each predetermined period of time of salivary exposure, the enamel blocks were removed from the appliances for immediate evaluation of surface hardness, enabling percentage of surface hardness recovery calculation (%SHR). The data were analyzed using two-way ANOVA and Tukey?s test (?=5%). The results showed no difference in the degree of enamel rehardening by the upper palatal or lower buccal appliances (p >0.0001). Regarding the time of use of the appliances, it was demonstrated that 30 minutes (upper = 21.12%, lower = 19.84%) and 1 hour (upper = 35.69%, lower = 30.50%) promoted lower hardness recovery than two hours (upper = 44.65%, lower 40.80%) of salivary exposure (p<0.0001). The use of 12 hours (upper = 49.33%, lower = 49.00%), including the sleeping time of the volunteers did not increase the %SHR. The location of the appliance does not influence the re-hardening ability of saliva and the use of intraoral appliances for 2 hours seems to be appropriate for partial rehardening of the softened enamel surface

Establishment of in vitro and in situ protocols for dental erosion studies

O objetivo foi comparar uma formulação de saliva artificial com e sem mucina (in vitro) com a saliva humana (in situ) na inibição da desmineralização (subprojeto I) e no reendurecimeto de lesões de erosão (subprojeto II), e a influência do tipo de dispositivo intrabucal (mandibular X palatino) no desgaste erosivo do esmalte (subprojeto III). No subprojeto I, blocos de esmalte bovino foram selecionados pela dureza de superfície e randomizados entre os grupos: GI - saliva humana (n=30), GII - saliva artificial sem mucina (n=15), GIII - saliva artificial com mucina (n=15) e GIV - água deionizada (n=15). Quinze voluntários utilizaram o dispositivo palatino por um período 2 horas (GI). Nos grupos GII, GIII e GIV, os blocos foram imersos em suas respectivas soluções por um período de 2 horas. Imediatamente após, tanto os blocos do grupo in situ quanto dos grupos in vitro foram submetidos ao desafio erosivo inicial com ácido cítrico 1% (pH 3,6) por 4 minutos. A microdureza final foi mensurada para determinar a porcentagem de perda de dureza. No subprojeto II, os blocos, após seleção, foram erodidos in vitro e randomizados entre grupos como no subprojeto I. Para a erosão, os blocos foram imersos em ácido cítrico 1% (pH 3,6) por 4 minutos. A seguir, no grupo GI, 15 voluntários utilizaram dispositivos palatinos durante 2 horas. Nos outros grupos os blocos foram imersos nas salivas artificiais com (GIII) e sem mucina (GII) e água deionizada (GIV) por 2 horas. A precipitação de minerais sobre o esmalte foi avaliada por meio da porcentagem de recuperação de dureza. No subprojeto III, após seleção dos blocos pela dureza, os mesmos foram aleatorizados em 2 grupos (n=20): GI - dispositivo palatino e GII - dispositivo mandibular. A ciclagem consistiu na imersão dos dois dispositivos em ácido clorídrico 0,01 M (pH 2,3) por 2 minutos, 4X/dia durante 5 dias. A perda do esmalte foi avaliada por perfilometria e os voluntários responderam a um questionário quanto ao conforto dos dispositivos. Nos subprojetos I e II, os dados foram submetidos aos testes ANOVA e Tukey e no subprojeto III foi aplicado o Teste T pareado (p<0,05). Nos subprojetos I e II observou-se que todas as salivas estudadas foram capazes de promover uma recuperação de dureza do esmalte e nenhuma diferença foi encontrada entre elas (p<0,05). No ensaio de desmineralização, a saliva artificial com mucina e a saliva humana (in situ) promoveram menor perda de dureza, não mostrando diferença entre elas (p<0,05). No subprojeto III os resultados mostraram que os blocos localizados no dispositivo palatino (GI) apresentaram maior desgaste erosivo quando comparados aos do dispositivo mandibular (GII). Além disso, todos voluntários relataram maior conforto no uso do dispositivo palatino. Considerando que o dispositivo palatino é mais confortável e resultou em maior perda de esmalte quando comparado ao mandibular, sugere-se o uso de dispositivos palatinos em protocolos in situ que queiram mimetizar pacientes com alto risco de erosão dentária. Para estudos in vitro, a saliva com mucina mostrou-se como uma boa substituta à saliva humana.The aim was to compare artificial saliva formulation with and without mucin (in vitro) with human saliva (in situ) on the inhibition of erosive demineralization (subproject I) and on the rehardening of erosion lesions (subproject II), and analyze the influence of the type of intraoral appliance (mandibular X maxillary) in enamel wear caused by erosive challenges (subproject III). In the subproject I, bovine enamel blocks were selected by initial surface hardness and randomized among the groups: GI - human saliva (n=30), GII - artificial saliva without mucin (n=15), GIII - artificial saliva with mucin (n=15) and GIV - deionized water (n=15). Fifteen volunteers wore palatal appliances for 2 hours (GI). In the GII, GIII and GIV groups, the blocks were immersed to the respective solutions for 2 hours. Subsequently, both in vitro and in situ blocks were subjected to initial erosive challenge in 1% citric acid (pH 3.6) for 4 minutes. Final enamel hardness was measured to determine the protective capacity of saliva tested by percentage of hardness loss. For the subproject II, after blocks selection, they were in vitro eroded and randomly among the groups as in subproject I. For erosion, the enamel blocks were immersed on 1% citric acid (pH 3.6) for 4 minutes. Then, in the GI, 15 volunteers wore palatal appliances for 2 hours. In the other groups the blocks were immersed in artificial saliva with (GIII) and without mucin (GII) and deionized water (GIV) for 2 hours. The minerals precipitation on the enamel was evaluated by the percentage of hardness recovery. On subproject III, after enamel blocks selection by surface hardness, they were randomly divided into 2 groups (n=20): GI - palatine appliance and GII - mandibular appliance. Erosive cycling consists in immersing of both devices in 0.01 M hydrochloric acid (pH 2.3) for 2 minutes, 4X/day during 5 days. The analysis of the wear was measured by profilometry and volunteers answered a questionnaire about the comfort of the devices. In the subprojects I and II, data were analyzed by one-way ANOVA and Tukeys test, and in the subproject III It was applied paired t-test (p <0.05). In subprojects I and II it was observed that all studied saliva promoted enamel rehardening and no difference was found between them (p <0.05). In the demineralization test, the artificial saliva with mucin and human saliva (in situ) provided lower enamel hardness loss, showing no difference between them (p<0.05). In the subproject III, the results showed that the specimens allocated in palatine appliance (GI) presented significantly higher erosive wear when compared to the specimens fixed in mandibular appliance (GII). In addition, all volunteers reported greater comfort in using the palatal device. Considering the palatal device is more comfortable and resulted in higher enamel loss when compared to the mandibular device, it is suggested the use of palatine appliances in in situ protocols who want to mimic a patient at high risk of dental erosion. For in vitro studies, the saliva with mucin might be a good substitute for human saliva

Influence of mandibular and palatal intraoral appliances on erosion in situ study outcome

Abstract The standardization of in situ protocols for dental erosion is important to enable comparison between studies. Objective: Thus, the objectives of this study were to evaluate the influence of the location of in situ intraoral appliance (mandibular X palatal) on the extent of enamel loss induced by erosive challenges and to evaluate the comfort of the appliances. Material and Methods: One hundred and sixty bovine enamel blocks were selected according to their initial surface hardness and randomly divided into two groups: GI - palatal appliance and GII - mandibular appliance. Twenty volunteers wore simultaneously one palatal appliance (containing 4 enamel blocks) and two mandibular appliances (each one containing 2 enamel blocks). Four times per day during 5 days, the volunteers immersed their appliances in 0.01 M hydrochloric acid for 2 minutes, washed and reinserted them into the oral cavity for 2 hours until the next erosive challenge. After the end of the in situ phase, the volunteers answered a questionnaire regarding the comfort of the appliances. The loss of tissue in the enamel blocks was determined profilometrically. Data were statistically analyzed by paired t-test, Chi-square and Fisher's Exact Test (p<0.05). Results: The enamel blocks allocated in palatal appliances (GI) presented significantly higher erosive wear when compared to the blocks fixed in mandibular appliances (GII). The volunteers reported more comfort when using the palatal appliance. Conclusions: Therefore, the palatal appliance is more comfortable and resulted in higher enamel loss compared to the mandibular one

Effect of vegetable oils applied over acquired enamel pellicle on initial erosion

Abstract Objective The prevalence of dental erosion has been recently increasing, requiring new preventive and therapeutic approaches. Vegetable oils have been studied in preventive dentistry because they come from a natural, edible, low-cost, and worldwide accessible source. This study aimed to evaluate the protective effect of different vegetable oils, applied in two concentrations, on initial enamel erosion. Material and Methods Initially, the acquired pellicle was formed in situ for 2 hours. Subsequently, the enamel blocks were treated in vitro according to the study group (n=12/per group): GP5 and GP100 – 5% and pure palm oil, respectively; GC5 and GC100 – 5% and pure coconut oil; GSa5 and GSa100 – 5% and pure safflower oil; GSu5 and GSu100 – 5% and pure sunflower oil; GO5 and GO100 – 5% and pure olive oil; CON− – Deionized Water (negative control) and CON+ – Commercial Mouthwash (Elmex® Erosion Protection Dental Rinse, GABA/positive control). Then, the enamel blocks were immersed in artificial saliva for 2 minutes and subjected to short-term acid exposure in 0.5% citric acid, pH 2.4, for 30 seconds, to promote enamel surface softening. The response variable was the percentage of surface hardness loss [((SHi - SHf) / SHf )×100]. Data were analyzed by one-way ANOVA and Tukey’s test (p0.05) and less than the other groups (p<0.05). There was no difference between GP5, GC5, GC100, GSa5, GSu100, GSa100, GSu5, GO5, GO100, CON− and CON+. Conclusion Palm oil seems to be a promising alternative for preventing enamel erosion. However, further studies are necessary to evaluate a long-term erosive cycling

Effect of different salivary exposure times on the rehardening of acid-softened enamel

Abstract This in situ study assessed the effect of different times of salivary exposure on the rehardening of acid-softened enamel. Bovine enamel blocks were subjected in vitro to a short-term acidic exposure by immersion in 0.05 M (pH 2.5) citric acid for 30 s, resulting in surface softening. Then, 40 selected eroded enamel blocks were randomly assigned to 10 volunteers. Intraoral palatal appliances containing 4 enamel blocks were constructed for each volunteer, who wore the appliance for 12 nonconsecutive hours: initial 30 min, followed by an additional 30, and then by an additional 1 hour. For the last additional 10 hours the appliances were used at night, during the volunteers’ sleep. Surface hardness was analyzed in the same blocks at baseline, after erosion and after each period of salivary exposure, enabling percentage of surface hardness recovery calculation (%SHR). The data were tested using repeated measures ANOVA and Tukey’s test (α = 0.05). Increasing periods of salivary action promoted a progressive increase in the surface hardness (p < 0.001). However a similar degree of enamel rehardening (p = 0.641) was observed between 2 hours (49.9%) and 12 hours (53.3%) of salivary exposure. Two hours of salivary exposure seems to be appropriate for partial rehardening of the softened enamel surface. The use of the intraoral appliance during sleep did not improve the enamel rehardening after erosion

Psychological Impact of the COVID-19 Pandemic on Dentists in Latin America&rsquo;s Epicenter: S&atilde;o Paulo, Brazil

The present study aimed to assess the prevalence and associated factors of stress and anxiety symptoms among dentists during the COVID-19 pandemic in the state of S&atilde;o Paulo, Brazil. A structured questionnaire was sent electronically to 93,280 dentists with active registration in the Dental Council of S&atilde;o Paulo, Brazil, enquiring about information regarding the first-wave peak period in Brazil. Descriptive analyses of background characteristics, perceptions of preparedness, and psychological impact were calculated. Multiple logistic regression analysis was performed, and independent variables that showed p &lt; 0.20 were used in the adjusted logistic regression model to compare the psychological impact on dental professionals. Among the 2113 respondents, female participants had 63% lower chance of reporting anxiety than males. Older dentists had a lower likelihood of reporting anxiety compared to 21&ndash;30-year-old dentists (p &le; 0.05). Dentists working in the public health service were 1.78 times more likely to report anxiety than those who worked in private practice. Finally, dentists in the COVID-19 high-risk group and those with a family or team member with a positive COVID-19 diagnosis were more likely to have anxiety. This study can help dental and other healthcare professionals to better understand the consequences of COVID-19 in terms of mental health