A Randomised trial to investigate the erosive effect of hot drinks.

Research on dental erosion has largely been undertaken at room temperature despite fruit juice drinks often being consumed at elevated temperatures in the United Kingdom, notably during periods of convalesce. The aim of the study was to evaluate the erosive potential of two fruit juices containing acidic non-alcoholic drinks at elevated temperatures in situ on human enamel after 5, 10 and 15 days. A commercially available conventional apple and blackcurrant fruit juice drink was compared to a blackcurrant juice drink modified to have low erosive potential, and mineral water consumed at approximately 59 °C. Twenty-one healthy volunteers aged 18 or over participated in a single-centre, single-blind (blinded to the investigator), three-treatment crossover study. Subjects were randomised to a treatment sequence using a Latin square design. Subjects wore upper removable appliances containing one human enamel specimen from 9 am to 5 pm for 15 days for each beverage. Measurements of enamel loss were recorded after 5, 10 and 15 days by contact surface profilometry. The low erosive blackcurrant drink caused significantly less enamel loss (P < 0·05) than the commercially available conventional apple and blackcurrant fruit juice drink and was not statistically significantly different to mineral water at any of the time points in the study. Consuming the modified low erosive blackcurrant drink at an elevated temperature resulted in negligible enamel loss in situ, consistent with room temperature findings.

The effect of chlorhexidine dentifrice or gel versus chlorhexidine mouthwash on plaque, gingivitis, bleeding and tooth discoloration: a systematic review.

OBJECTIVE: To systematically review and evaluate the available scientific evidence on the effectiveness of chlorhexidine dentifrice or gel (CHX DF/gel) compared to chlorhexidine mouthwash (CHX MW) on plaque, bleeding, gingival inflammation and tooth discoloration scores. MATERIAL AND METHODS: PubMed-MEDLINE, Cochrane-CENTRAL and EMBASE databases were searched to identify appropriate studies. RESULTS: Independent screening of the 2256 unique titles and abstracts resulted in five publications that met the eligibility criteria. Considerable heterogeneity was found between the studies. Three of the five studies showed a positive effect on plaque scores in favour of the CHX MW. With respect to gingival index and bleeding scores, no significant differences were found. Chlorhexidine mouthwash, however, showed a significantly more tooth discoloration than the CHX DF/gel. A meta-analysis of the effect on 'de novo' plaque formation of CHX DF/gel versus CHX MW resulted in a difference in means of 0.27 [95% CI: 0.14; 0.39] (P < 0.0001). CONCLUSION: Chlorhexidine gel can be successfully formulated and will inhibit plaque growth to some degree, but not to the same extent, as a CHX MW. When CHX DF/gel is used in a non-brushing model, it is significantly less effective in plaque inhibition compared to CHX MW. Based on one study when CHX gel was applied with a finger after brushing, it is significantly more effective on plaque scores and the gingival index. The only brushing study also with a long follow-up showed that there is no significant difference between CHX DF and CHX MW. However, as a corollary, significantly more tooth discoloration was observed with the CHX MW. Altogether, the data show that when daily oral hygiene cannot be performed, CHX MW is the first product of choice.

The efficacy of chlorhexidine dentifrice or gel on plaque, clinical parameters of gingival inflammation and tooth discoloration: a systematic review.

AIM: Based on the existing scientific literature, the effect of chlorhexidine (CHX) dentifrice/gel as compared to a regular or placebo dentifrice/gel is established in healthy adults on the primary outcome parameters of plaque and gingivitis scores. As secondary parameter, tooth surface discoloration was evaluated as a side effect. MATERIALS AND METHODS: MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials were searched up to July 2013 to identify eligible studies. Included were (randomized) controlled clinical trials, regarding self-performed brushing by adults without periodontitis with a minimum duration of 4 weeks. RESULTS: Independent screening of 389 unique titles and abstracts resulted in 16 comparisons. Of these, nine evaluated CHX dentifrice (0.4-1.0%) and 7 CHX gel (0.2-2.0%). It was not possible to perform a meta-analysis; therefore, a descriptive analysis was carried out. Regarding plaque score reduction, the majority of the experiments using a CHX dentifrice provided a significant positive effect. All studies assessing gingival bleeding as parameter for gingivitis observed a significant reduction in favour of CHX dentifrice over placebo dentifrice. Tooth surface discoloration was more pronounced with CHX dentifrice. The combined data concerning parameters of interest for CHX gel compared with a placebo did not show a trend towards a beneficial effect on plaque and bleeding scores. CONCLUSIONS: Within the limitations of this analysis, it may be concluded that toothbrushing with a CHX gel does not provide conclusive evidence. Brushing with a CHX dentifrice can be effective with regard to the control of plaque and gingivitis. Tooth surface discoloration was observed as side effect, which potentially can have a negative impact on patients' compliance.

Effects of pH and acid concentration on erosive dissolution of enamel, dentine, and compressed hydroxyapatite.

The aims of this study were to determine the effects of pH and acid concentration on the dissolution of enamel, dentine, and compressed hydroxyapatite (HA) in citric acid solutions (15.6 and 52.1 mmol l(-1) ; pH 2.45, 3.2, and 3.9), using a pH-stat system. After an initial adjustment period, the dissolution rates of enamel and HA were constant, while that of dentine decreased with time. The dissolution rate increased as the pH decreased, and this was most marked for enamel. To compare substrates, the rate of mineral dissolution was normalized to the area occupied by mineral at the specimen surface. For a given acid concentration, the normalized dissolution rate of HA was always less than that for either dentine or enamel. The dissolution rate for dentine mineral was similar to that for enamel at pH 2.45 and greater at pH 3.2 and pH 3.9. The concentration of acid significantly affected the enamel dissolution rate at pH 2.45 and pH 3.2, but not at pH 3.9, and did not significantly affect the dissolution rates of dentine or HA at any pH. The variation in response of the dissolution rate to acid concentration/buffer capacity with respect to pH and tissue type might complicate attempts to predict erosive potential from solution composition.

Enamel erosion in dietary acids: inhibition by food proteins in vitro.

The aim of this study was to investigate the effects of two common food proteins on human enamel erosion in vitro. Erosion was measured by non-contact profilometry in citric, malic and lactic acids at pH 2.8, 3.2 and 3.8 and five commercially available soft drinks, in the presence of a salivary pellicle. Whole milk casein or hen egg ovalbumin was added to the acid solutions and drinks at 0.2% w/v, and the effect on erosion was determined by comparison with the corresponding solution without protein. Casein significantly reduced erosion in all but two solutions. The effects of the individual subfractions of casein in citric acid at pH 3.2 were similar to that of whole casein. Ovalbumin reduced erosion in some solutions, but the magnitude of the reduction was less than that with casein. A greater proportional reduction in erosion was seen in citric acid than in malic or lactic acids. We postulate that the mechanism involves adsorption of proteins to the pellicle or the enamel surface, forming a protein film with enhanced erosion-inhibiting properties. The citrate ion may play an active stabilising role, since erosion reduction was less in the other acids. In conclusion, casein and, to a lesser extent, ovalbumin show promise as potential anti-erosive additives to drinks.

Clinical in situ study investigating abrasive effects of two commercially available toothpastes.

The aim of this study was to determine if the abrasive effect on dentine of two commercially available toothpastes, known to vary in their in vitro abrasive levels, can be differentiated in an in situ model after 10 days, assessed by contact profilometry. This was a single centre, single blind, randomized, split mouth, two treatment, in situ study, in 34 healthy subjects, evaluating the abrasive effects of two marketed desensitizing toothpastes, (Colgate Sensitive Multi Protection toothpaste - C; Sensodyne Total Protection - S). Subjects wore bi-lateral, lower buccal appliances, each fitted with four dentine sections which were power brushed three times a day with the treatment regimen. Each subject received two toothpaste treatments for 10 days during the treatment period. Samples were measured at baseline and day 10 by contact and non-contact profilometry and day 5 by contact profilometry. Thirty-four subjects were included in the efficacy analysis. Results from contact profilometry showed statistically significant (P < 0.0001) dentine loss compared to baseline at day 5 and 10 for both pastes. At each time point, C showed statistically significantly greater dentine loss than S, P < 0.0001. After 10 days treatment, the difference in dentine loss between the pastes was 1.4 microm. The non-contact profilometry data showed similar trends. After 10 days of treatment, C showed statistically significantly greater dentine loss than S, with treatment difference of 0.9 microm, P = 0.0057. The methodology used has successfully differentiated between the abrasivity of the two pastes in respect of dentine surface loss over time in an in situ environment.

Development of an in situ methodology for the clinical evaluation of dentine hypersensitivity occlusion ingredients.

OBJECTIVE: The aim of these clinical studies was to evaluate an in situ dentine tubule occlusion model, and to determine the occluding effect from novel occluding agents on patent dentine tubules compared to a positive control (8% strontium acetate--Sensodyne Mint) and negative control (a non-occluding agent) after four days of brushing treatment. METHODS: These two in situ clinical studies were of single-center, randomized, crossover, single-blind design. Healthy participants wore two lower intra-oral appliances retaining four dentine samples for four treatment days for each period of the study. Samples were power-brushed each day with the test product. Assessment utilized surface topological analysis with a replica-based methodology under scanning electron microscopy (SEM). RESULTS: Both clinical trials demonstrated that the positive control (8% strontium acetate) occluded dentine tubules significantly better (p = 0.0007; p < 0.0009) than the negative controls in the two studies, respectively. The experimental occluding agents demonstrated varying degrees of success for occluding effect compared to the controls. CONCLUSION: The methodology clearly demonstrates that this in situ clinical model can robustly and reproducibly detect the dentine tubular occlusive effects of positive and negative controls in the treatment of dentine hypersensitivity brushed on the dentine surface. Using this methodology, new occlusion agents for the relief of dentine hypersensitivity can be assessed for occlusive effects on dentine.

Inhibition of hydroxyapatite dissolution by ovalbumin as a function of pH, calcium concentration, protein concentration and acid type.

Hydroxyapatite is the main constituent of the dental hard tissues, and in vivo its dissolution in acids leads to the pathological condition of dental erosion. Food proteins which inhibit hydroxyapatite dissolution may find application as erosion-reducing agents in food and drink products. The aim of this study was to investigate the egg protein ovalbumin as a potential inhibitor of hydroxyapatite dissolution in acidic solutions, with conditions representative of dental erosion. The dissolution rate of hydroxyapatite discs was measured in an acidic solution as a function of pH, calcium concentration, ovalbumin concentration and acid type. All experiments were performed in triplicate. 0.2% w/v ovalbumin significantly reduced the dissolution rate in citric acid by 50-75% over the pH range 2.80-4.00, and by 45-60% in solutions with calcium concentrations of up to 20 mM (p < 0.05). The effect was persistent for several rinses after the initial exposure to the protein. 0.02% w/v ovalbumin significantly reduced the dissolution of hydroxyapatite in citric acid by 30-55%. Ovalbumin did not, however, statistically significantly reduce the hydroxyapatite dissolution rate in malic or lactic acids. The effect is ascribed to adsorption and partial, reversible denaturation of ovalbumin on the hydroxyapatite surface. There may be some interaction between ovalbumin and the citrate ion which promotes the adsorption of protein in the presence of citric acid. Ovalbumin shows promise as a potential erosion-reducing additive to citrus-based drinks.

Toothpaste detergents: a potential source of oral soft tissue damage?

OBJECTIVES: Toothpastes are thought to be of benefit to cleaning teeth but may also have the potential for soft tissue damage at least on the cellular level by inclusion of detergents in their formulation. The aim of this study was to observe the in vitro response of oral mucosa like cells to toothpaste detergents. METHODS: TERT-1 keratinocytes were exposed to varying concentrations of the detergents Adinol, Sodium Lauryl Sulphate, Tego Betain and Pluronic as well as PBS and culture medium. After 2-min exposure, cells were washed and incubated in fresh medium for 24 h. Cell death was then spectrophotometrically measured using an MTT assay. RESULTS: Except for Pluronic, cell viability was markedly reduced for all detergents at all increasing concentrations when compared to the positive medium control. Cells treated with Pluronic were stimulated compared to medium alone. CONCLUSIONS: These in vitro data suggest that some detergents may have the potential to cause soft tissue damage in the mouth. Although in vivo, saliva may neutralize such effects. The results for Pluronic suggest a possible oxidative stress response that bears further study.

The Cardiff Dental Survey: oral hygiene, gingival and periodontal health in relation to smoking in young adults.

OBJECTIVE: To examine the relationship between tobacco smoking, oral hygiene, gingival and periodontal health in young adults. STUDY DESIGN: Cross-sectional (conducted in the course of a cohort study). SETTING: Cardiff, UK, 1989 and 2000. METHODS: Plaque was recorded, as was presence or absence of bleeding on probing and loss of attachment (LA). Information concerning tobacco smoking was obtained from questionnaire data. RESULTS: At age 19-20 years, smokers had statistically significantly (P < 0.01) higher whole mouth mean plaque scores than non-smokers. Whole mouth mean bleeding scores, however, were similar in smokers and non-smokers. The relationship of plaque to smoking was very similar at age 30-31, yet bleeding scores were approximately 25% lower in smokers than in non-smokers (P < 0.01). Whole mouth LA scores showed small, statistically non-significant differences between smokers and non-smokers. At the age of 30-31 years, gender and social class had a negligible confounding effect on oral hygiene, gingival and periodontal health in smokers and non-smokers. CONCLUSIONS: Smokers consistently demonstrated poorer oral hygiene than non-smokers. The effect of smoking in reducing gingival bleeding was already apparent at age 19-20 years despite the fact that, at this time, subjects might be assumed to have been exposed to a relatively small dose of tobacco over a short period of time. In the follow-up study conducted at the age of 30-31 years, the impact of smoking on the periodontal tissues was, as expected, more pronounced.

The effect of saliva derived from different individuals on the erosion of enamel and dentine. A study in vitro.

UNLABELLED: The aim of this study was to determine if saliva from 14 subjects afforded different levels of protection to human enamel and dentine against erosion in vitro. Test specimens were exposed for 2 h to saliva and control specimens to water for 2 h followed by citric acid for 10 min. This cycle was carried out 12 times. Tissue loss measured by contact profilometry was highly significantly different between subjects. Erosion was significantly reduced by pre-treatment with saliva from 7 subjects (enamel) or 6 subjects (dentine). Saliva from 1 subject resulted in significantly more enamel erosion than control. CONCLUSION: Saliva from different donors affords different levels of protection against erosion.

The protective effects of toothpaste against erosion by orange juice: studies in situ and in vitro.

OBJECTIVES: There has been a monumental increase in the consumption of soft drinks, fruit juices and sport drinks in the UK, the US, and many other countries. Previous investigations have demonstrated the erosive nature of these acidic soft drinks. The aim of this investigation was to determine the protective effects of an experimental fluoride-based toothpaste, containing sodium hexametaphosphate, against an erosive challenge on tooth enamel. METHODS: The erosion of enamel by orange juice compared the experimental toothpaste with a benchmark sodium fluoride paste and negative control, water, in a 15-day in situ model; and the same in an in vitro enamel erosion model. Flat, polished human enamel samples with a surface profile of +/-0.1mum, were exposed to the three regimens in the single blind, crossover clinical study mimicked in vitro. Depths of the resulting eroded areas were measured using a profilometer. RESULTS: There was significantly more erosive damage on the specimens exposed to the benchmark paste and water compared to the test paste in both the in situ and in vitro studies. CONCLUSIONS: The data provide further support for tooth brushing before meals. Results of this study further suggest the sodium hexametaphosphate containing paste could be used to provide significant erosion protection in susceptible individuals over that provided by conventional fluoride products.

A clinical study in situ to assess the effect of a food approved polymer on the erosion potential of drinks.

OBJECTIVES: The consumption of acidic soft drinks continues to rise as do concerns regarding effects of frequent intake. The aim of the study was to determine the effect of acidic soft drinks containing food approved polymers, on dental enamel. METHODS: The study design was a single blind, randomised, five-treatment crossover clinical trial involving 15 healthy dentate subjects. Subjects wore an upper removable acrylic appliance retaining two enamel specimens and consumed 250ml of beverage four times/day for 10 days. The following beverages were tested: (1) unmodified acidic soft drink, (2) experimental acidic soft drink with 0.02% polyphosphate, (3) experimental acidic soft drink with 0.02% polyphosphate and 0.01% calcium, (4) experimental acidic soft drink with 0.02% polyphosphate and 0.03% xanthan gum, and (5) mineral water. Tissue loss was measured at days 5 and 10 of each study leg using a profilometer. RESULTS: The order of erosion from most to least at day 10 was unmodified acidic soft drink>experimental acidic soft drink with polyphosphate>experimental acidic soft drink with polyphosphate+gum>experimental acidic soft drink with polyphosphate+calcium>mineral water. At day 10 the unmodified acidic soft drink was significantly (p=0.001) more erosive than all other drinks. CONCLUSIONS: Unmodified acidic soft drink with the addition of polyphosphate alone or combined with calcium or xanthan gum are all effective at reducing erosion of enamel compared with the unmodified soft acidic drink.

The relationship between enamel softening and erosion caused by soft drinks at a range of temperatures.

OBJECTIVES: Investigations of the erosive potential of soft drinks are usually performed at room or body temperature, but drinks are more frequently served chilled, with ice, or hot. Since the rate of chemical reactions usually increases with temperature, it is predicted that erosion is more severe at high temperatures and reduced at low temperatures. The aim of this study was to investigate the correlation between enamel softening, enamel erosion, and temperature. METHODS: Atomic force microscopy nanoindentation and non-contact optical profilometry were used to assess changes in enamel nanomechanical properties after 5 min and erosive material loss after 30 min exposure to two different non-carbonated soft drinks at 4, 25, 50 and 75 degrees C. RESULTS: For one drink (Robinson's Original Juice Drink), there was a statistically significant difference between nanomechanical properties and erosion depth at all temperatures, with softening and erosion increasing with temperature. For another drink (Ribena ToothKind Juice Drink), there was a slight softening and virtually no material loss, and temperature had no statistically significant impact on erosion. There was a good linear correlation (R2 = 0.94) between nanomechanical properties and material loss. CONCLUSIONS: The difference between the drinks can be explained by their composition. For the erosive drink, material loss increased, and nanohardness decreased, approximately linearly with temperature. The correlation between softening and erosion demonstrated that nanomechanical properties after very short erosion times can be considered a good predictor of bulk material loss after considerably longer erosion times.

Surface and pulp chamber temperature rises during tooth bleaching using a diode laser: a study in vitro.

OBJECTIVE: To measure the surface and pulp chamber temperature increases in vitro on upper and lower anterior teeth during a tooth whitening procedure using a diode laser. METHOD: A thermocouple was used to measure the temperature increase on the surface of an extracted upper central incisor tooth. Pulp chamber temperature readings were made on upper and lower central incisors, lateral incisors and canines. A diode laser recommended for tooth bleaching was tested at three different power settings (1W, 2W, 3W). Temperature measurements were made with and without the bleaching agent present on the labial tooth surface. RESULTS: The increase in surface temperature readings ranged from 37 degrees C (1W) to 86.3 degrees C (3W) with no bleaching gel present. Pulp chamber temperature increases ranged from 4.3 degrees C (1W) to 16 degrees C (3W). The presence of the bleaching gel reduced temperature increases seen at the tooth surface and within the pulp. CONCLUSIONS: The increase in the pulp chamber temperature with the laser used at 1-2W was below the critical temperature increase of 5.5 degrees C thought to produce irreversible pulpal damage. However, a power setting of 3W produced a pulp chamber temperature increase above this threshold (16 degrees C) and caution is advised when using this setting.

Erosion of enamel by non-carbonated soft drinks with and without toothbrushing abrasion.

OBJECTIVE: To investigate how enamel loss due to erosion, and due to cycling of erosion and abrasion, depends on compositional parameters of soft drinks, and particularly whether the thickness of the erosive softened layer is a function of drink composition. SETTING: University dental hospital research laboratory in the UK, 2004. MATERIALS AND METHODS: Six drinks were chosen based on their popularity and composition: apple juice, orange juice, apple drink, orange drink, cranberry drink and 'ToothKind' blackcurrant drink. Group A samples (n = 36) were exposed to soft drinks at 36 degrees C for six consecutive 10 minute periods. Group B samples (n = 36) were subjected to alternating erosion and toothbrushing, repeated six times. Enamel loss was measured using optical profilometry. RESULTS: Group A: significant enamel loss was seen for all drinks (p < 0.001). Erosion was correlated with pH and calcium concentration but not phosphate concentration or titratable acidity. Group B: significant additional material loss due to toothbrush abrasion occurred with all drinks. Abrasive enamel loss differed between the drinks and was positively correlated with drink erosive potential. CONCLUSION: Enamel loss by erosion is exacerbated by subsequent abrasion. The amount of softened enamel removed by toothbrushing is a function of the chemical composition of the erosive medium.

In vitro studies on the effect of sodium tripolyphosphate on the interactions of stain and salivary protein with hydroxyapatite.

OBJECTIVES: To study properties of sodium tripolyphosphate (STP) relevant to inhibition or removal of dental stain in vitro. METHODS: The effects of STP and other phosphates on adsorption of a dietary chromogen (black tea polyphenol) and salivary protein to hydroxyapatite (HA) powder were studied by analysing loss of protein or tea stain from solutions mixed with HA or HA pre-treated with the test agents. The effects on desorption of protein and stain from HA were studied by analysis of water or solutions of test agents mixed with HA or HA pre-treated with saliva or tea solution. RESULTS: At concentrations and pH representative of those likely to occur in the mouth, STP inhibited adsorption of salivary protein and black tea polyphenol to, and desorbed these substances from, HA surfaces. Adsorption and desorption of protein and stain were not influenced by pH of the STP solutions but adsorption varied with concentration. STP showed equivalent effectiveness with respect to salivary protein adsorption and desorption as a longer-chain condensed phosphate. The inhibitory activity of HA-bound STP on adsorption of salivary protein and stain resisted extensive washing. CONCLUSIONS: STP is likely to be an effective agent for inhibiting and removing dental stain, whether bound directly to mineralised surfaces or indirectly via salivary pellicle.

A comparison of a reformulated potassium citrate desensitising toothpaste with the original proprietary product.

OBJECTIVES: The recent tendency for toothpaste manufacturers to combine active ingredients for benefits to a number of oral problems requires that such combinations do not vitiate the action of any one agent. The aim of this study was to compare the desensitising effects of a modified formulation with the established product. MATERIALS AND METHODS: The study was a randomised, double blind, two treatment parallel design comparing an existing potassium citrate toothpaste product (Positive Control) with the same formulation to which triclosan and zinc citrate had been added (Test). A total of 56 subjects with dentine hypersensitivity (DH) completed the 8 week study period. At baseline, days 14 and 56 visual analogue scale scores were recorded by the subjects in response to air evaporative and cold water stimuli. RESULTS: Both groups showed improvements, mostly statistically significant, from baseline to day 14 and through to day 56. Most data favoured the Test paste but differences were, for the most part, not significant. CONCLUSIONS: It is concluded that the addition of known anti-plaque agents to an established potassium salt based desensitising toothpaste did not adversely affect the activity of the product in the treatment of DH.

The bleaching depth of a 35% hydrogen peroxide based in-office product: a study in vitro.

OBJECTIVES: The aim of the present study was to quantify the penetration of 35% hydrogen peroxide into enamel and dentine and to relate this to the resultant shade change of the tooth. METHOD: The crowns of 24 caries and developmental defect free human maxillary incisors were stained internally with a standardised tea solution. Twelve specimens were power bleached with light activated 35% hydrogen peroxide and 12 placed in water; both exposure times were 30min. Three different shade assessment methods (Vita shade guide [SG], shade vision system [SVS] and a chromometer) were employed prior to, after tea staining and after power bleaching/water treatments. Twelve specimens each from the bleach group and the water control water group were sectioned mesio-distally. An additional 12 specimens from the bleach and the control group were sectioned labio-palatally. The stain area for each specimen was measured using image analysis software. RESULTS: With tea staining, the mean changes in Vita shade guide units (SGU) ranged from 3.66 to 8.33. With the SVS system changes of 3.66-9 units were seen. Chromometer readings showed that following bleaching the L* values moved in the direction of black (3.8-6.7) and a* and b* values were in the red (0.3) and yellow (1.5) direction, respectively. Samples bleached and sectioned mesio-distally showed stain coverage of 28.6-39.4%, while palatal sections showed stain coverage of 58-72%. Control samples, whether sectioned mesio-distally or labio-palatally, showed staining throughout the dentine (97-100% coverage). CONCLUSION: A 35% hydrogen peroxide in-office bleaching gel demonstrated bleaching into dentine of uniform depth.