Effects of Nitrate and Nitrite on Plaque pH Decrease and Nitrite-Producing and -Degrading Activities of Plaque in vitro.

INTRODUCTION: The purpose of this study was to investigate the effects of nitrate and nitrite on the pH-lowering activity of human plaque, the nitrite-producing and -degrading activities of human plaque, and their correlation. METHODS: Nitrate and nitrite were added to human plaque suspensions collected from the buccal aspect of maxillary molars of patients visiting a general dental clinic, and changes in pH were measured with and without glucose addition. Nitrite-producing and -degrading activities were evaluated by adding nitrate and nitrite to the plaque suspension and measuring the increase and decrease in nitrite with Griess reagent, respectively. RESULTS: The addition of nitrate inhibited both endogenous and glucose-induced plaque pH-lowering. The addition of glucose enhanced the production of nitrite from nitrate by about 3.3-fold. The addition of nitrite also inhibited endogenous plaque pH-lowering, but the addition of glucose promoted nitrite degradation by only about 1.1-fold. Nitrite-producing activity was positively correlated with age, but not with nitrite-degrading activity. CONCLUSION: This study revealed that nitrite was produced from nitrate and inhibited the pH-lowering activity of human plaque, which may contribute to caries control. Both nitrite-producing and -degrading activities occurred in human plaque, but no correlation was found between them. Furthermore, nitrite production was enhanced by glucose metabolism, which may function as a self-regulatory mechanism (resilience) to prevent excessive acidification by glucose metabolism.

Assessment of Cariogenicity by pH-value Decrement of Plaque Solution with Four Infant Milk Formulas: An In Vitro Study.

Introduction: People all over the world use a wide variety of infant formulas to nourish the infants. Recent studies demonstrated the high caries-inducing potential of infant formulas. This indicates a need for awareness toward the possible role of the infant formulas in the etiology of early childhood caries (ECC). Aim: The present study was undertaken to evaluate and comparatively assess the change in plaque pH solutions after fermenting four commonly used infant milk formulas. Materials and methods: This simple randomized study was carried out on 40 healthy children aged 4-6 years old. The children received full-mouth prophylaxis before examination. They were asked not to implicate oral hygiene for 24 hours and not to have anything at least 2 hours prior the study. Supragingival plaque from the buccal surface of posterior teeth was collected using a Hu-Friedy's curette. Four commonly used infant milk formulas were prepared and given to children for rinsing. The pH of plaque samples were measured at 30 and 60 minutes at 37°C. Results: The present study showed that all of the four infant milk formulas decreased the mean pH values in plaque solutions significantly after 30 and 60 minutes of preparation. Conclusion: Our results showed that the plaque pH varied in response to the oral rinsing with the various infant formulas and most of infant formulas were able to reduce the pH significantly below the pH before the rinse. Based upon this study further evaluation of the cariogenicity of infant formulas is recommended. How to cite this article: Pandey A, Pathivada L, Kajapuram P, et al. Assessment of Cariogenicity by pH-value Decrement of Plaque Solution with Four Infant Milk Formulas: An In Vitro Study. Int J Clin Pediatr Dent 2022;15(3):263-266.

Effect of drops containing Lactobacillus reuteri (DSM 17938 and ATCC PTA 5289) on plaque acidogenicity and other caries-related variables in orthodontic patients.

BACKGROUND: The purpose of the study was to investigate the effect of probiotics on biofilm acidogenicity and on the number of salivary Streptococcus mutans and lactobacilli in orthodontic patients. METHODS: This RCT was conducted on 28 young adults who were undergoing orthodontic treatment. The short-term prospective clinical trial lasted for three weeks. The test group rinsed daily with drops containing two Lactobacillus reuteri strains diluted in water, while the placebo group used drops without probiotics. The subjects were enrolled eight months since the beginning of orthodontic treatment. Plaque-pH, saliva and dental biofilm samples were obtained at baseline, one week and three weeks post intervention. RESULTS: Twenty-seven subjects successfully completed the trial period, only one drop out in the test group. No side effects were reported. A statistically significant increase in plaque pH at three weeks post-intervention was found for the test group (p < 0.05), while insignificant changes in the pH value were found for the placebo group in comparison to baseline (p > 0.05). In addition, the AUC7.0 showed a significant difference at three weeks between the test and placebo (p = 0.00002). The three-week samples of stimulated whole saliva showed a statistically insignificant difference in the number of S. mutans and lactobacilli between the two groups (p > 0.05). The qPCR analysis showed the ability of the two strains to get colonized in the dental biofilm without a significant effect on the microbial counts. CONCLUSION/CLINICAL IMPLICATIONS: A mixture of Lactobacillus reuteri has the ability to reduce the pH fall at the three-week follow-up. However, the short-term use of probiotics does not appear to have an effect on the number of salivary Streptococcus mutans and lactobacilli in saliva and on the dental biofilm. TRIAL REGISTRATION: Clinicaltrial.gov (Identifier: NCT04593017 / (19/10/2020)).

The Impact of Carbohydrate Quality on Dental Plaque pH: Does the Glycemic Index of Starchy Foods Matter for Dental Health?

Sugary carbohydrate foods have long been associated with increased risk of dental caries formation, but the dental health impact of starchy carbohydrates, particularly those with a high glycemic index (GI), has not been well examined. AIM: To investigate the effect of different starchy foods varying in their GI, on acute changes in dental plaque pH. METHODS: In a series of sub-studies in healthy adults, common starchy carbohydrate foods, including white bread, instant mashed potatoes, canned chickpeas, pasta, breakfast cereals, white rice, and an oral glucose solution were consumed in fixed 25 g available carbohydrate portions. The change in dental plaque pH was assessed postprandially over 1 h and capillary plasma glucose was measured at regular intervals over 2 h. RESULTS: Higher GI starchy foods produced greater acute plaque pH decreases and larger overall postprandial glucose responses compared to lower GI starchy foods (white bread compared with canned chickpeas: -1.5 vs. -0.7 pH units, p = 0.001, and 99 ± 8 mmol/L min vs. 47 ± 7 mmol/L min, p = 0.026). Controlling for other food factors (food form and nutritional composition), lower GI versions of matched food pairs produced smaller plaque pH excursions compared to higher GI versions of the same food. Using linear regression analysis, the GI value of starchy carbohydrate foods explained 60% of the variation in maximum plaque pH nadir and 64% of the variation in overall acute dental plaque pH excursion (p < 0.01). CONCLUSION: The findings imply that starchy foods, in particular those with a higher GI, may play a role in increasing the risk of dental caries.

Effect of Lactobacillus brevis CD2 containing lozenges and plaque pH and cariogenic bacteria in diabetic children: a randomised clinical trial.

OBJECTIVE: The short-term effect (60 days) of Lactobacillus brevis CD2 lozenges vs placebo on variables related to caries and gingivitis in type 1 diabetic children was evaluated. MATERIAL AND METHODS: Eight diabetics (4-14 years old) were assigned to two groups (n = 34 subjects each), probiotic lozenges and placebo. Stimulated saliva for microbiological analysis and plaque pH were assessed at baseline (t0), 30 days (t1), 60 days (t2) and in the follow-up period (90 days from baseline, t3). Gingival status was assessed at t0, t2 and t3. Two-way ANOVA assessed differences between groups. RESULTS: In the probiotic group, Streptococcus mutans bacterial density mean scores dropped from 3.11 ± 1.13 at baseline to 1.82 ± 0.72 (t2) and to 2.06 ± 0.56 (t3), while in the placebo group, the scores were 3.09 ± 0.8 (t0), 2.82 ± 0.47 (t2) and 3.11 ± 0.43 (t3) (p < 0.01). Lowest and maximum pH fall increased in the probiotic group, from 5.37 ± 0.41 at baseline to 5.49 ± 0.24 at t3 (p < 0.01) and from 1.20 ± 0.46 to 0.98 ± 0.29 (p = 0.02). Bleeding score decreased significantly in both groups, showing a statistically significant lower bleeding score at t2 in the probiotic group (25.6%, 95% CI 21.5-32.7 vs 29.5%, 95% CI 25.2-34.9, p = 0.02). CONCLUSIONS: Lactobacillus brevis CD2 has shown to improve caries-related risk factors and gingival health in diabetic children. CLINICAL RELEVANCE: Lactobacillus brevis CD2 might contribute to improved oral health in type 1 diabetic children.

Acidogenic Potential of Packaged Fruit Juices and its Effect on Plaque and Salivary pH.

AIM: The aim of this study was to analyze the acidogenic potential of the various commercially available fruit juices and to evaluate the salivary and plaque pH changes before and after consumption of the fruit juices that were kept at various temperatures. MATERIALS AND METHODS: Baseline plaque and salivary pH were measured for 30 volunteers, and the test was conducted for 4 consecutive days on which juices with a known pH was consumed, which were kept at varying temperatures. The resulting changes in the plaque and salivary pH were measured after 1, 5, 15, and 30 minutes of the consumption of the fruit juices using a portable standard digital pH meter. RESULTS: Among the three juices compared, grape juice was found to be more acidic compared to the orange juice and pineapple juice. The pH fall was maximum after consumption of grape juice followed by orange and pineapple juice, respectively. The consumption of ice candy caused a greater fall in pH followed by the refrigerated juice and the juices that were kept at room temperature, respectively. CONCLUSION: Parents are unaware of the harmful effects of endogenous acids in the fruit juices and their effect on the teeth. We, as primary dental care providers, should take initiatives to provide adequate knowledge and information regarding this new trend of consuming frozen fruit juices and must strongly discourage this form of consumption as a frequent habit. CLINICAL SIGNIFICANCE: Though many presume that the readily available fruit juices are healthy, frequent consumption of these fruit juices causes acid dissolution of enamel as most of these juices have a pH below the critical level. Hence the present study was conducted to evaluate the erosive potential of the various commercial fruit juices. As with increased awareness by both the dentists and the parents, the problem of fruit-juice-induced tooth loss may be reduced. HOW TO CITE THIS ARTICLE: Mehta LK, Hegde A, et al. Acidogenic Potential of Packaged Fruit Juices and its Effect on Plaque and Salivary pH. Int J Clin Pediatr Dent 2019;12(4):312-317.

Dental plaque pH in predicting caries relapse after general anaesthesia - an exploratory study.

OBJECTIVES: Numerous caries risk assessment tools have been proposed in the literature, with few validated in preschool children especially those receiving oral rehabilitation under general anaesthesia (GA). Past caries experience, the best predictor thus far, may not be a reliable indicator after effective clinical intervention. Hence, this longitudinal study was aimed to explore the potential role of plaque pH in predicting future caries incidence after GA among preschool children. METHODS: Oral examination, plaque pH measurements and questionnaire survey were performed, among pre-schoolers indicated for GA, at baseline (n = 92), 6-month (6M; n = 83), 12-month (12M; n = 79) and 24-month (24M; n = 66) recall visits after GA. Multivariable logistic regression and receiver-operating characteristic analysis were performed to evaluate the predictive value of models with plaque pH and past caries experience. RESULTS: Individuals with low resting plaque pH at 6M and 12M were shown to be at high risk of 1-year caries incidence at 12M [relative risk (RR) 1.41, 95% confidence interval (CI) 1.09-1.48] and 24M (RR 1.61, 95% CI 1.22-1.73) recall visit, respectively. Moreover, plaque pH demonstrated a statistically significant predictive value in the 12M and 24M models (12M/24M: 85%/77%) compared with past caries experience, which was not a significant predictor in both models (both P > 0.05). CONCLUSIONS: Plaque pH may be a promising prognostic and predictive marker for early identification of high-risk children undergoing oral rehabilitation under GA.

Anticariogenic potential of white cheese, xylitol chewing gum, and black tea.

OBJECTIVE: This study aimed to examine the effects of these foods on plaque pH and the potential development of tooth decay. MATERIALS AND METHODS: Plaque pH was measured using the sampling method before and after 1, 5, 10, 20, 30, 45, and 60 min following consumption of these foods individually and after rinsing with a 10% sucrose solution. Statistical analysis was performed using one-way ANOVA and Tukey honestly significant difference post hoc tests (α = 0.05). RESULTS: Although there were statistically significant differences in all test groups except the BT (P = 0.620) and sucrose + XCG (P = 0.550) groups in time, none of the participants chosen for this study were having a plaque pH value anywhere close to the critical value (pH = 5.5). CONCLUSION: WC, BT, and XCG are advisable as anticariogenic foods because pH values are not below critical value.

Influence of dental plaque pH on caries status and salivary microflora in children following comprehensive dental care under general anesthesia.

BACKGROUND/PURPOSE: There is no report in examining dental plaque pH after dental care under general anesthesia. This study investigated the effects of comprehensive dental rehabilitation under general anesthesia on the oral environment of children with severe early childhood caries (S-ECC) and the influence of dental plaque pH on caries recurrence and salivary microflora. MATERIALS AND METHODS: Thirty-seven children (mean age, 51.08 ± 9.68 months) with S-ECC who underwent comprehensive dental treatment under general anesthesia were selected. Caries index, plaque pH, and Streptococcus mutans (SM) and Lactobacillus (LB) counts were evaluated during the initial examination and 6-month and 12-month follow-ups. RESULTS: The plaque pH was significantly greater at the 6-month follow-up examination than at the initial examination (P = 0.006) and at the 12-month follow-up (P = 0.002), but there was no significant difference in plaque pH between the initial examination and the 12-month follow-up (P = 0.942). SM and LB counts at the sixth and twelfth months were significantly lower than the initial counts (P < 0.001). Plaque pH did not show strong correlations with caries index and SM and LB counts at the three time-points (P > 0.05). CONCLUSION: The comprehensive dental rehabilitation under general anesthesia for children with S-ECC caused a temporary significant increase in the plaque pH at the sixth month and a significant reduction in the salivary microflora during the 12-month follow-up. Plaque pH did not demonstrate any strong correlations with caries status and salivary microflora in children with S-ECC.

Impact of Alcohol Dependency on Oral Health - A Cross-sectional Comparative Study.

INTRODUCTION: Alcoholism is a chronic and progressive psychiatric illness characterised by a loss of control over alcohol consumption. Consumption of alcohol inevitably affects the oral cavity, oral mucosa and teeth. Literature indicates that alcohol dependents may have increased risk of dental caries, probing pocket depth and mucosal lesions. AIM: To assess the impact of alcohol dependency on oral health status among alcoholics in comparison with non alcoholics. MATERIALS AND METHODS: A total 76 alcoholic patients visiting Psychiatric Department were compared with matched non alcoholics. Subjects were categorised as alcohol dependents based on American Psychiatric Association Diagnostic and Statistical Manual of Mental Disorders (DSM-5) diagnostic criteria. Non alcoholic subjects were selected by controlling for potentially confounding variables such as for cigarette, smoking and age. Data was collected by interview and clinical examination. Oral health status of subjects was assessed using a modified WHO proforma and salivary pH and plaque pH were assessed. Chi-square test was used for assessing socio demographic details and Mann-whitney U test was used for prevalence of dental caries and periodontal diseases, Unpaired t-test was used for plaque and salivary pH. RESULTS: There was no statistically significant difference noted among alcoholic and nonalcoholic control group with respect to socio demographic details. Prevalence of dental caries was higher in alcohol dependent subjects with a mean DMFT of 5.92 compared to nonalcoholic subjects (4.51). Prevalence of periodontitis was higher (89.61%) in alcohol dependent subjects compared to controls (78.67%). Prevalence of mucosal lesions among alcohol dependent subjects was 31.5% which was higher than the controls (25%). Subjects who were categorised as alcoholics showed a lower plaque and salivary pH compared to non alcoholics. CONCLUSION: Subjects categorised as alcohol dependent subjects had slightly lower mean plaque and salivary pH and a higher prevalence of dental caries, periodontitis and mucosal lesions compared with non alcoholic subjects.

The Influence of Pregnancy on Sweet Taste Perception and Plaque Acidogenicity.

Objectives Women undergo different physiological and oral changes during pregnancy and this may increase the risk of dental caries and other oral diseases. The aim of the present study was to investigate changes in biofilm acidogenicity and correlate them to sweet taste perception in pregnant and non-pregnant women. Methods Three groups of Saudi women participated in this cross-sectional study: (1) women in early pregnancy (n = 40/mean age 29.6 years/DMFT 10.7), (2) women in late pregnancy (n = 40/29.5 years/DMFT 10.8) and (3) non-pregnant women (n = 41/27.7 years/DMFT 12.3). Changes in plaque pH were determined by using colour-coded indicator strips before and after a 1-min rinse with a 10% sucrose solution. A taste perception test determining sweet preference and threshold levels was also performed. Results A significant difference regarding plaque pH was seen between the early, late and non-pregnant women when calculated as the area under the curve (p < 0.05). Regarding the taste perception tests, taste preference and threshold were correlated (p < 0.001, r = 0.6). Between the three groups, a statistically significant difference was seen in taste threshold and taste preference respectively (p = 0.001 and p < 0.001). Conclusions The findings in this study suggest that pregnant women may undergo taste changes and experience lower plaque pH, which may result in an increased risk of dental caries.

DMFT index assessment, plaque pH, and microbiological analysis in children with special health care needs, India.

AIM: To assess the DMFT index of children with Special Health Care Needs (SHCN) in Navi Mumbai. To correlate the DMFT index with Streptococcus mutans count in the supragingival bacterial biofilm and with plaque pH. MATERIALS AND METHODS: Dental examination of 158 patients aged 5-18 years was conducted to determine the DMFT/dmft index. Supragingival plaque samples were collected from the buccal surfaces of all teeth. The samples were inoculated in mitis salivarius bacitracin agar medium and incubated at 37°C for 48 h. Supragingival plaque was collected from interproximal sites of the molar area (preferably mandibular) for conducting plaque pH test. Chi-square test and Pearson's correlation were used to find the significance of the study parameters on categorical scale between the two groups. RESULTS: The mean DMFT recorded was 4.90 ± 4.63 and the mean dmft recorded was 1.77 ± 3.14. Mean number of S. mutans colony-forming units found was 2.961 × 10(4). Mean plaque pH recorded was 6.2. CONCLUSION: No statistically significant correlation was found between the DMFT index with the number of S. mutans and plaque pH.

Effect of dietary combinations on plaque pH recovery after the intake of pediatric liquid analgesics.

OBJECTIVES: To study the effect of water, halloumi cheese and sugar-free (SF) chewing gum on plaque pH recovery after the intake of sweetened PLAs. SETTINGS AND DESIGN: A randomized clinical trial was conducted on 17 children (10 females, 7 males) aged 11-12 years with DFT/dft of more than 3. MATERIALS AND METHODS: Each volunteer tested paracetamol and ibuprofen suspension alone or followed with water, halloumi cheese or SF gum, as well as 10% sucrose and 10% sorbitol as controls. Plaque pH was measured using the sampling method before and after 5, 10, 15, 20, 30 min of ingestion. STATISTICAL ANALYSIS: Statistical analysis was performed using analysis of variance followed by least significant difference test to assess minimum pH (min pH), maximum pH drop (ΔpH), and the area under baseline pH, and P value was set as 0.05. RESULTS: Both ibuprofen and paracetamol were not significantly different from 10% sucrose in terms of min pH, ΔpH, and area under baseline pH except for min pH of ibuprofen (P = 0.034). Water and halloumi cheese did not have a significant effect on plaque pH recovery after the intake of both analgesics as min pH, ΔpH, and area under baseline pH were similar to 10% sucrose except for min pH of ibuprofen + water (P = 0.048). However, plaque pH variables after chewing SF gum for 20 min were similar to 10% sorbitol. CONCLUSION: Chewing SF gum immediately after the intake of sweetened PLAs for 20 min restores plaque pH and could be recommended as a complementary aid in caries prevention.

Effect on oral pH changes and taste perception in 10-14-year-old children, after calcium fortification of a fruit juice.

AIM: The aim was to determine the effect of calcium fortification of a commercially available mixed-fruit juice on oral pH changes and taste perception in a group of 10 to 14 year-old Indian children. METHOD: A controlled, blinded, non-randomised clinical trial was adopted, consisting of a sample of 100 healthy children (DMFT <3; age 10-14 years), who were exposed to three test juices one by one [Group A: original fruit juice (control group); Group B: calcium-fortified fruit juice and Group C: calcium + vitamin D fortified fruit juice]. Oral pH, collection of saliva and plaque sampling was undertaken, before and after the juice exposure by each subject at 0, 1, 5, 15, 30 and 45 min. The respective pH was measured with a digital pH meter. For taste perception, a scoring system was used after exposure of the juices to the subjects in a blind manner. The statistical evaluation was done using one-way ANOVA for salivary and plaque pH and Kruskal-Wallis test for buffer capacity and taste perception. RESULTS: There was a smaller drop in salivary and plaque pH (p < 0.5) and a significant reduction in perceived taste (p < 0.001) by the subjects after calcium modification of fruit juice. CONCLUSION: The calcium-modified mixed fruit juices was less acidogenic compared with the unfortified juice, and hence will be less cariogenic and erosive towards teeth.

Oral rehydration therapy products - a plaque pH study under normal and dry mouth conditions.

AIM: The aim of this study was to investigate oral rehydration therapy (ORT) products and their effect on plaque pH under normal and dry mouth conditions. DESIGN: Three commercial oral rehydration therapy products, prepared according to the manufacturers' instruction, plus a 10% glucose solution, which served as control, were tested in 10 healthy subjects (mean age 25 years): (1) Electral (Arrow Pharmaceuticals), (2) Resorb Junior (Nestlé) and (3) Vätskeersättning (Semper). pH was measured in the maxillary premolar region in situ with the so-called microtouch method. The area under the pH curve was calculated. Their carbohydrate content was also analysed. RESULTS: The oral rehydration therapy products gave the same low pH values in plaque as the glucose solution. Dry mouth condition, obtained by injection of methylscopolamine nitrate in the labial sulcus, resulted in an overall more pronounced fall in pH and in a delay in the pH recovery compared with normal salivary conditions. The chemical analyses showed that all three test-products contained glucose and starch as the main carbohydrates. CONCLUSIONS: Rinsing with oral rehydration therapy products leads to a greater pH decrease in dental plaque during low compared with normal salivary conditions. As diarrhoea may result in dehydration and thereby in dry mouth, we believe that ORT products have a high cariogenic potential.

The effects of beverages on plaque acidogenicity after a sugary challenge.

BACKGROUND: Caries prevention traditionally has emphasized the restriction of cariogenic foods and beverages, but it has placed less emphasis on how the choice, combination and sequence of consumed foods and beverages may help reduce plaque acidogenicity. The authors conducted a study to examine whether whole milk, 100 percent apple juice or tap water affect dental plaque acidity in people after a sugary challenge. METHODS: Twenty adults participated in a randomized controlled crossover study. Participants consumed four combinations of foods: 20 grams of dry sugary Froot Loops (FL) (Kellogg's, Battle Creek, Mich.) cereal, 20 g of FL followed by 50 milliliters of milk (FL/milk), 20 g of FL followed by 50 mL of juice (FL/juice) and 20 g of FL followed by 50 mL of water (FL/water). The authors used a touch microelectrode to take plaque pH readings at the interproximal space just below the contact area between the maxillary premolars on both left and right sides at two and five minutes after FL consumption and at two to 30 minutes after milk, juice or water consumption. RESULTS: Consumption of FL plaque pH (standard deviation [SD]) was 5.83 (0.68) at 30 minutes, whereas plaque pH (SD) in the FL/milk group was 6.48 (0.30), which was significantly higher than that for FL/juice (5.83 [0.49]) or FL/water (6.02 [0.41]) (P < .005) at 35 minutes. CONCLUSION: Drinking milk after a sugary cereal challenge significantly reduced plaque pH drop due to the sugary challenge. PRACTICAL IMPLICATIONS: When discussing the cariogenicity of foods and beverages with patients, dentists and other health care professionals should emphasize that the order of ingesting sugary and nonsugary foods is important and may affect their oral health.

In vivo dental plaque pH after consumption of dairy products.

This in vivo study assessed plaque pH in subjects following the consumption of different dairy products. After receiving parental consent to participate, subjects (12-15 years old) were asked to refrain from brushing their teeth for 48 hours prior to the study. At baseline, plaque pH was determined at 4 different sites. Each of the subjects was then assigned randomly to 1 of 4 subgroups and each subgroup was given either cheese, milk, yogurt, or paraffin (control). After baseline, all subjects were allowed to chew and/or swish their respective product for 3 minutes and pH was assessed subsequently at different time intervals. Statistical analysis was performed using unpaired t-test and 1-way ANOVA. The results showed a statistically significant change in mean plaque pH after consuming different dairy products, as the plaque pH after 30 minutes was higher in the cheese group than that of the milk and yogurt groups, both of which showed a pH toward baseline after 30 minutes. These results suggest that cheese has the highest anticariogenic property among the dairy products studied, and that milk and yogurt can be considered as noncariogenic.