Impact of toothbrush head configuration and dentifrice abrasivity on non-carious cervical lesions in-vitro

OBJECTIVE

To investigate the effect of toothbrush head configuration and dentifrice slurry abrasivity on the development of simulated non-carious cervical lesions (NCCLs) in vitro.

METHODS

Extracted premolars were randomly allocated into 15 groups (n = 16) generated by the association between toothbrush head configuration (flat-trimmed, rippled, cross-angled/multilevel/rubbers added, cross-angled/multilevel/flex head, feathered) and dentifrice slurry abrasivity (low/medium/high). Teeth were mounted on acrylic blocks and had their roots partially covered with acrylic resin, leaving 2-mm root surfaces exposed. Toothbrushing was performed for 35,000 and 65,000 double-strokes. Specimens were analyzed using non-contact profilometry for dental volume loss (mm3) and lesion morphology. Data was analyzed using ANOVA with pairwise comparisons and Kruskal-Wallis tests.

RESULTS

The two-way interaction between toothbrush head configuration and slurry abrasivity was significant (p = 0.02). At 35,000 strokes, the flat-trimmed and cross-angled/multilevel/rubbers added toothbrushes caused the highest loss, when associated to the high-abrasive slurry (p<0.05); whereas cross-angled/multilevel/flex head showed the least loss, when associated to the low-abrasive (p<0.05). At 65,000, more dental loss was observed for all toothbrushes when associated to the high-abrasive slurry, with flat-trimmed causing the highest loss (p < 0.05). Lower dental loss rates were observed for cross-angled/multilevel/flex head associated to the low-abrasive slurry when compared to the other toothbrushes (p < 0.05), except to feathered (p = 0.14) and rippled (p = 0.08). Flat lesions (mean internal angle ± standard-deviation: 146.2°± 16.8) were mainly associated with low-abrasive slurry, while wedge-shaped lesions (85.8°± 18.8) were more frequent with medium- and high-abrasive slurries.

CONCLUSION

The development, progression and morphology of simulated NCCLs were modulated by both toothbrush head configuration and dentifrice abrasivity.

CLINICAL SIGNIFICANCE

Dental professionals should consider both the type of toothbrush and dentifrice abrasivity in the management plan of patients at risk of developing NCCLs.

Qualitative Analysis of Opinions and Beliefs Associated with the Use of Tobacco Dentifrice among Individuals Attending a Tobacco Counselling Session

BACKGROUND

Smokeless tobacco (SLT) use is positively associated with oral, oesophageal, and pancreatic cancers. The tobacco dentifrice is a type of SLT which is applied to the teeth and gums. It is available in different forms which include mishri, gul/gulmanjan, gudhaku, snuff, red tooth powder, and creamy snuff. This qualitative study aims to explore the opinions and beliefs associated with the harmful effects of tobacco dentifrice use.

METHODOLOGY

Thirty in-depth interviews were conducted among tobacco dentifrice users visiting a dental hospital. The data were coded and analysed using thematic analysis in ATLAS.ti software 8.

RESULTS

A total of 11 codes and six categories were generated which comprised of the reason for the initiation, awareness of health effects, perception of oral tobacco application, perception of quitting, the reason for continued use, and use in society. Family, peers, access to the product, curiosity were important factors to initiate the tobacco dentifrice use. Participants believed in the myth that tobacco dentifrice was beneficial for the teeth, gums, and bowel movements. The participants considered tobacco dentifrice to be less harmful than other forms of tobacco. However, some participants were aware of its adverse effects on health and have tried to quit in the past. None of the participants had taken any professional help for quitting.

CONCLUSION

There were strong beliefs and myths among the participants that tobacco dentifrice was beneficial for oral and general health. There is a need to create awareness and improve the standard of the health warning of such products.

Evaluation of Antimicrobial Effect of Air-Polishing Treatments and Their Influence on Human Dental Pulp Stem Cells Seeded on Titanium Disks

Dental implants are one of the most frequently used treatment options for tooth replacement, and titanium is the metal of choice due to its demonstrated superiority in resisting corrosion, lack of allergic reactions and mechanical strength. Surface roughness of titanium implants favors the osseointegration process; nevertheless, its topography may provide a suitable substrate for bacterial biofilm deposition, causing peri-implantitis and leading to implant failure. Subgingival prophylaxis treatments with cleansing powders aimed to remove the bacterial accumulation are under investigation. Two different air-polishing powders—glycine and tagatose—were assayed for their cleaning and antimicrobial potential against a Pseudomonas biofilm and for their effects on human dental pulp stem cells (hDPSCs), seeded on sandblasted titanium disks. Immunofluorescence analyses were carried out to evaluate cell adhesion, proliferation, stemness and osteogenic differentiation. The results demonstrate that both the powders have a great in vitro cleaning potential in the early period and do not show any negative effects during hDPSCs osteogenic differentiation process, suggesting their suitability for enhancing the biocompatibility of titanium implants. Our data suggest that the evaluated cleansing systems reduce microbial contamination and allow us to propose tagatose as an adequate alternative to the gold standard glycine for the air-polishing prophylaxis treatment.

Baking soda as an abrasive in toothpastes: Mechanism of action and safety and effectiveness considerations

BACKGROUND

Toothpastes can be formulated with different abrasive systems, depending on their intended clinical application. This formulation potentially affects their effectiveness and safety and, therefore, requires proper understanding. In this article, the authors focused on abrasive aspects of toothpastes containing sodium bicarbonate (baking soda), which have gained considerable attention because of their low abrasivity and good compatibility, while providing clinical effectiveness (further detailed in the other articles of this special issue). The authors first appraised the role of toothpaste abrasivity on tooth wear, exploring some underlying processes and the existing methods to determine toothpaste abrasivity.

TYPES OF STUDIES REVIEWED

The authors reviewed the available data on the abrasivity of toothpastes containing baking soda and reported a summary of findings highlighting the clinical implications.

CONCLUSIONS

On the basis of the collected evidence, baking soda has an intrinsic low-abrasive nature because of its comparatively lower hardness in relation to enamel and dentin. Baking soda toothpastes also may contain other ingredients, which can increase their stain removal effectiveness and, consequently, abrasivity.

PRACTICAL IMPLICATIONS

Even those formulations have abrasivity well within the safety limit regulatory agencies have established and, therefore, can be considered safe.

An exploratory study to investigate stain build-up with long term use of a stannous fluoride dentifrice

PURPOSE

To monitor extrinsic stain formation over 24 weeks with twice-daily use of an anhydrous 0.454% SnF2 dentifrice containing 5% sodium tripolyphosphate (STP) ('Test'), compared to a standard fluoride dentifrice (0.76% fluoride as sodium monofluorophosphate [SMFP\) ('Comparator') following a professional prophylaxis.

METHODS

Primary efficacy variables were between-treatment differences in extrinsic dental stain of anterior teeth after 4, 8, 12, and 24 weeks' use using mean area and intensity scores of the MacPherson modification of the Lobene stain index (MLSI), and to monitor oral tolerability.

RESULTS

Overall, 214 subjects were randomized to treatment. The Test dentifrice group demonstrated statistically significantly less stain compared with the Comparator at each timepoint for all outcome variables (MLSI - Area × Intensity, Area only, and Intensity only) with the exception of MLSI (Area × Intensity) at Week 12. Products were generally well tolerated with 26 treatment-related adverse events (TRAEs) reported (10 with Test, 16 with Comparator). Five subjects withdrew from the 24-week study due to TRAEs, three in the Test group, two in the Comparator group. Statistically significantly less anterior tooth staining was observed with up to 24 weeks twice-daily brushing with a 0.454% SnF2/5% STP anhydrous dentifrice compared to a marketed fluoride dentifrice with 0.76% SMFP.

CLINICAL SIGNIFICANCE

Long term use of a SnF2/STP dentifrice demonstrated minimal stain build-up after 24 weeks, twice-daily use; products were generally well-tolerated.

A Profilometry-Based Dentifrice Abrasion Method for V8 Brushing Machines Part III: Multi-Laboratory Validation Testing of RDA-PE

OBJECTIVES

We have previously reported on progress toward the refinement of profilometry-based abrasivity testing of dentifrices using a V8 brushing machine and tactile or optical measurement of dentin wear. The general application of this technique may be advanced by demonstration of successful inter-laboratory confirmation of the method. The objective of this study was to explore the capability of different laboratories in the assessment of dentifrice abrasivity using a profilometry-based evaluation technique developed in our Mason laboratories. In addition, we wanted to assess the interchangeability of human and bovine specimens.

METHODS

Participating laboratories were instructed in methods associated with Radioactive Dentin Abrasivity-Profilometry Equivalent (RDA-PE) evaluation, including site visits to discuss critical elements of specimen preparation, masking, profilometry scanning, and procedures. Laboratories were likewise instructed on the requirement for demonstration of proportional linearity as a key condition for validation of the technique. Laboratories were provided with four test dentifrices, blinded for testing, with a broad range of abrasivity. In each laboratory, a calibration curve was developed for varying V8 brushing strokes (0, 4,000, and 10,000 strokes) with the ISO abrasive standard. Proportional linearity was determined as the ratio of standard abrasion mean depths created with 4,000 and 10,000 strokes (2.5 fold differences). Criteria for successful calibration within the method (established in our Mason laboratory) was set at proportional linearity = 2.5 ± 0.3. RDA-PE was compared to Radiotracer RDA for the four test dentifrices, with the latter obtained by averages from three independent Radiotracer RDA sites. Individual laboratories and their results were compared by 1) proportional linearity and 2) acquired RDA-PE values for test pastes.

RESULTS

Five sites participated in the study. One site did not pass proportional linearity objectives. Data for this site are not reported at the request of the researchers. Three of the remaining four sites reported herein tested human dentin and all three met proportional linearity objectives for human dentin. Three of four sites participated in testing bovine dentin and all three met the proportional linearity objectives for bovine dentin. RDA-PE values for test dentifrices were similar between sites. All four sites that met proportional linearity requirement successfully identified the dentifrice formulated above the industry standard 250 RDA (as RDA-PE). The profilometry method showed at least as good reproducibility and differentiation as Radiotracer assessments. It was demonstrated that human and bovine specimens could be used interchangeably.

CONCLUSIONS

The standardized RDA-PE method was reproduced in multiple laboratories in this inter-laboratory study. Evidence supports that this method is a suitable technique for ISO method 11609 Annex B.

Abrasion of eroded and sound enamel by a dentifrice containing diamond abrasive particles

Eroded enamel is more susceptible to abrasive wear than sound enamel. New toothpastes utilizing diamond particles as abrasives have been developed. The present study investigated the abrasive wear of eroded enamel by three commercially available toothpastes (one containing diamond particles) and compared it to the respective wear of sound enamel caused by these toothpastes. Seventy-two bovine enamel samples were randomly allocated to six groups (S1–S3 and E1–E3; n=12). Samples were submitted to an abrasive (S1–S3) or erosion plus abrasion (E1–E3) cycling. Per cycle, all samples were brushed (abrasion; 20 brushing stokes) with the following toothpastes: S1/E1: Signal WHITE SYSTEM, S2/E2: elmex KARIESSCHUTZ and S3-E3: Candida WHITE DIAMOND (diamond particles). Groups E1–E3 were additionally eroded with HCl (pH 3.0) for 2 min before each brushing procedure. After 30, 60 and 90 cycles enamel wear was measured by surface profilometry. Within the same toothpaste and same number of cycles, enamel wear due to erosion plus abrasion was significantly higher than due to mere abrasion. After 30, 60 and 90 cycles, no significant difference in the wear in groups S1 and S2 was observed while the wear in group E1 was significantly (p<0.05, ANOVA, Scheffecyc) lower than that in group E2. After 90 cycles, wear in group S3 was about 5 times higher than that in group S2, while wear in group E3 was about 1.3 times higher than that in group E2. As compared to the other two investigated toothpastes, the dentifrice containing diamond particles caused slightly higher abrasive wear of eroded enamel and distinctly higher wear of sound enamel compared to the conventional toothpastes under investigation.

Charcoal and charcoal-based dentifrices: A literature review

BACKGROUND

Sales of charcoal dentifrices and powders have rapidly emerged into the Internet marketplace. The authors conducted a literature review to examine the efficacy and safety of charcoal and charcoal-based dentifrices.

METHODS

The authors searched the MEDLINE and Scopus databases for clinical studies on the use of charcoal and charcoal-based dentifrices and laboratory investigations on the bioactivity or toxicity of charcoal and charcoal-based dentifrices, published through February 2017. The authors used a defined search strategy to identify randomized, controlled clinical trials with a follow-up duration of 3 months or longer. In addition, the authors selected the first 50 consecutive charcoal dentifrices from Google.com and Amazon.com for ascertainment of product assortment and advertising promotions.

RESULTS

The authors' literature search identified 118 potentially eligible articles. Thirteen studies reported brushing the teeth with raw charcoal or soot; however, none of these studies met the inclusion criteria. Two studies offered nonspecific caries reductions, 3 studies reported deleterious outcomes (increased caries, enamel abrasion, nonquantified negative impact), and 1 study indicated only that brushing with raw charcoal had no adverse effects on oral hygiene. Seven other studies reported only on the use of charcoal for oral hygiene. Internet advertisements included unsubstantiated therapeutic claims-such as antibacterial, antifungal, antiviral, and oral detoxification, as well as potentially misleading product assertions. One-third of the charcoal dentifrices contained bentonite clay, and 1 contained betel leaves.

CONCLUSIONS

The results of this literature review showed insufficient clinical and laboratory data to substantiate the safety and efficacy claims of charcoal and charcoal-based dentifrices. Larger-scale and well-designed studies are needed to establish conclusive evidence.

PRACTICAL IMPLICATIONS

Dental clinicians should advise their patients to be cautious when using charcoal and charcoal-based dentifrices with unproven claims of efficacy and safety.

A Profilometry-Based Dentifrice Abrasion Method for V8 Brushing Machines Part II: Comparison of RDA-PE and Radiotracer RDA Measures

OBJECTIVE

The purpose of this study was to compare the abrasivity of commercial dentifrices by two techniques: the conventional gold standard radiotracer-based Radioactive Dentin Abrasivity (RDA) method; and a newly validated technique based on V8 brushing that included a profilometry-based evaluation of dentin wear. This profilometry-based method is referred to as RDA-Profilometry Equivalent, or RDA-PE.

METHODS

A total of 36 dentifrices were sourced from four global dentifrice markets (Asia Pacific [including China], Europe, Latin America, and North America) and tested blindly using both the standard radiotracer (RDA) method and the new profilometry method (RDA-PE), taking care to follow specific details related to specimen preparation and treatment.

RESULTS

Commercial dentifrices tested exhibited a wide range of abrasivity, with virtually all falling well under the industry accepted upper limit of 250; that is, 2.5 times the level of abrasion measured using an ISO 11609 abrasivity reference calcium pyrophosphate as the reference control. RDA and RDA-PE comparisons were linear across the entire range of abrasivity (r2 = 0.7102) and both measures exhibited similar reproducibility with replicate assessments. RDA-PE assessments were not just linearly correlated, but were also proportional to conventional RDA measures.

CONCLUSION

The linearity and proportionality of the results of the current study support that both methods (RDA or RDA-PE) provide similar results and justify a rationale for making the upper abrasivity limit of 250 apply to both RDA and RDA-PE.

A profilometry-based dentifrice abrasion Method for V8 brushing machines. Part I: Introduction to RDA-PE

OBJECTIVE

This paper describes the development and standardization of a profilometry-based method for assessment of dentifrice abrasivity called Radioactive Dentin Abrasivity - Profilometry Equivalent (RDA-PE).

METHODS

Human dentine substrates are mounted in acrylic blocks of precise standardized dimensions, permitting mounting and brushing in V8 brushing machines. Dentin blocks are masked to create an area of "contact brushing." Brushing is carried out in V8 brushing machines and dentifrices are tested as slurries. An abrasive standard is prepared by diluting the ISO 11609 abrasivity reference calcium pyrophosphate abrasive into carboxymethyl cellulose/glycerin, just as in the RDA method. Following brushing, masked areas are removed and profilometric analysis is carried out on treated specimens. Assessments of average abrasion depth (contact or optical profilometry) are made.

RESULTS

Inclusion of standard calcium pyrophosphate abrasive permits a direct RDA equivalent assessment of abrasion, which is characterized with profilometry as Depth test/Depth control x 100. Within the test, the maximum abrasivity standard of 250 can be created in situ simply by including a treatment group of standard abrasive with 2.5x number of brushing strokes. RDA-PE is enabled in large part by the availability of easy-to-use and well-standardized modern profilometers, but its use in V8 brushing machines is enabled by the unique specific conditions described herein.

CONCLUSION

RDA-PE permits the evaluation of dentifrice abrasivity to dentin without the requirement of irradiated teeth and infrastructure for handling them. In direct comparisons, the RDA-PE method provides dentifrice abrasivity assessments comparable to the gold industry standard RDA technique.

A randomized clinical study investigating the staining profile of an experimental stannous fluoride dentifrice

PURPOSE

The primary objective of this study was to investigate the staining profile of an experimental test dentifrice containing 0.454% w/w stannous fluoride compared to that of a marketed control dentifrice containing 0.76% w/w sodium monofluorophosphate (Colgate Cavity Protection) following regular and repeat use, with twice daily brushing over 8 weeks. As an exploratory objective, the staining profile of the test dentifrice was compared to that of a marketed comparator dentifrice containing 0.454% w/w stannous fluoride (Crest Pro-Health - Clean Mint).

METHODS

This was a single-center, examiner-blind, randomized, three arm, parallel group study, stratified by pre-baseline stain score [total Lobene Stain Index (LSI) (area x intensity) score < 31, > or = 31] and smoking status. Following initial screening, 137 healthy subjects, aged 18 years and above, with 12 gradable anterior teeth returned for baseline assessments. At the baseline visit, subjects received an oral soft tissue (OST) examination and an assessment of extrinsic dental stain using the LSI on the facial and lingual surfaces of the 12 anterior teeth, LSI area, LSI intensity and LSI area x intensity (the LSI area x intensity score was termed the pre-baseline LSI score). Subjects who met study requirements received a dental prophylaxis of the anterior teeth to remove all visible stain from their tooth surfaces such that an LSI (area x intensity) score of 0 was achieved. Randomized subjects brushed with their assigned dentifrice at home twice daily for 1 timed minute and returned after 4 and 8 weeks for an OST examination and dental stain assessment of the anterior teeth using LSI.

RESULTS

There were no statistically significant differences in dental stain build-up between the test dentifrice containing 0.454% w/w stannous fluoride and a marketed control dentifrice (Colgate Cavity Protection), after 4 and 8 weeks of twice daily brushing, in terms of LSI area x intensity, LSI area or LSI intensity scores. Exploratory analysis indicated that the marketed stannous fluoride dentifrice (Crest Pro-Health) exhibited more dental stain build-up at 4 and/or 8 weeks compared to the other two study dentifrices. However, post-hoc analysis revealed an imbalance in LSI baseline stain levels between the treatment groups, with higher stain levels in the marketed comparator group, which made it difficult to draw robust conclusions from the exploratory data. This imbalance was not considered to impact the other study analyses. Study treatments were well tolerated.

A preliminary study to find a possible association between occlusal wear and maximum bite force in humans

OBJECTIVE

The objective of the study was to investigate whether moderate-to-severe attrition is associated with maximum bite force in the first molar region.

METHODOLOGY

Maximum bite force in the first molar region was measured for a total of 60 subjects having moderate-to-severe attrition of occlusal surface (experimental group) using a specially-designed piezoelectric sensor based bite force measuring device. An equal number of age, gender, height and weight matched controls (control group) were also subjected to bite force measurement for comparison.

RESULTS

The maximum bite force was found to be significantly lower (p < 0.05) in the experimental group [480.32 (153.40)] as compared to the controls [640.63 (148.90)]. While analyzing the possible etiology for occlusal wear mainly two reasons were elicited, i.e. history of parafunctional habits like use of known abrasive tooth powder (sub-group A) and Bruxism (sub-group B). However, there were many subjects in which no known definite etiological factors be attributed to occlusal wear (sub-group C). On analysing further with respect to the possibly correlated etiological factors with maximum bite force, no significant difference was found within the experimental sub-group. However, all three experimental sub-groups had significantly lower maximum bite force as compared to age, gender and BMI matched controls.

CONCLUSION

A significantly lower maximum bite force was found to be associated with moderate-to-severe attrition as compared to subjects without attrition. However, no specific relation could be found between bite force and possible etiological factors like history of parafunctional habits, history of use of known abrasive tooth powder, etc.

Enamel hardness after exposure to acidic drinks and brushing

This study tested the hypothesis that short-term exposure to acidic drinks can reduce enamel surface hardness, and that subsequent brushing with toothpaste can cause detectable loss of enamel. Enamel specimens (three groups per storage medium) were immersed in one of four acidic drinks for five seconds, one minute, or 10 minutes. The pH values of all four drinks were measured. Six microhardness indentations were made on each specimen before immersion (baseline), after immersion, and after brushing with toothpaste. Changes in surface microhardness were expressed as the ratio of hardness values after each treatment to the baseline value of each specimen. Two-way ANOVA showed that both storage medium and duration of immersion influenced the ratio significantly. One-way ANOVA showed that the ratio was reduced significantly with increased time of immersion in drinks with a pH =2.8, but the ratio reduction was not significant in drinks with a pH =3.3. Subsequent brushing removed the softened layer and exposed intact surface underneath. Although short-term exposure (~5 seconds) did not significantly affect the surface hardness values, it left a lightly etched enamel surface among specimens immersed in acidic drinks with a low pH. Subsequent brushing could still cause detectable loss of enamel surface after multiple exposures.

Assessment of alpha radioactivity in lipstick, nailpolish, toothpaste and vermilion using CR-39 detector

Human beings are always exposed to radiation from chemical cosmetics. In order to collect information regarding the radioactivity of chemical cosmetics used in our daily life, we studied the alpha radioactivity in different cosmetics samples, such as lipsticks, nail-polish, toothpaste and vermilion. The significant accumulation ofradionuclide in and on the tissues, directly or indirectly exposed due to the lipsticks, toothpaste, vermilion, may cause health hazards. Different samples of these cosmetic materials (Indian and foreign brands) were collected from the local markets of Kolkata, India. CR-39--a useful solid state nuclear track detector (SSNTD) was used to detect alpha radioactivity of these samples. Such exhaustive measurement of radioactivity in lipsticks, nail-polish, toothpaste and vermilion has not been reported so far.

The effect of anti-sensitivity dentifrices on brushing abrasion of eroded dentin in vitro

OBJECTIVE

To investigate the abrasive effects of three marketed anti-sensitivity, and one marketed regular dentifrice on dentin, using an erosion-abrasion in vitro model.

METHODS

Standardized human dentin specimens were prepared and exposed to cycles of erosion, remineralization, and tooth brushing, utilizing the four commercially available dentifrices. Dentin surface loss was then measured by optical profilometry after a total of nine complete cycles. The RDA and pH values of the dentifrices were also measured to assist in the interpretation of results.

RESULTS

Profilometry showed significantly greater dentin surface loss for both Colgate Sensitive Fresh Stripe and Colgate Sensitive Multi Protection when compared with Sensodyne Total Protection or Crest Cavity Protection dentifrices. The abrasive level of dentifrices correlated positively (r-squared = 0.66; p < 0.05) with dentin surface loss.

CONCLUSION

This study demonstrated that the abrasivity of dentifrices can have a significant effect on the wear of eroded dentin in vitro.

Photographic assessment of fluorosis in children from naturally fluoridated Kungsbacka and non-fluoridated Halmstad, Sweden

OBJECTIVES

To assess levels of fluorosis and fluorosis of esthetic concern in children from a naturally fluoridated and a non-fluoridated area of Sweden, and to determine the relative contributions of fluoridated water, parental educational level, and infant oral health-related behaviors.

METHODS

A parental questionnaire collected information concerning child F-supplement and F-dentifrice usage histories, and socio-economic status. Photographic examination of 1336 subjects (F=791; N-F=545) was undertaken. Fluorosis was assessed (blind to F-exposure) in a random sample (n=250) of 35 mm slides by four dental and two lay "jurors" (with 10% random repeat-viewing for inter-observer and intra-observer agreement). Four outcomes were assessed on each slide: fluorosis at any level, fluorosis of esthetic concern, acceptability of appearance, and treatment needs. Ordinal logistic regression models were used to determine significant determinants.

RESULTS

For presence of fluorosis of esthetic concern, majority jury agreements (>3 of 6) were seen in only 2.3% (N-F) and 13.4% (F) pupils (p<0.001), albeit jurors unanimously scored only 13 F and 2 N-F exposed children as having esthetically unacceptable fluorosed teeth (p<0.001). The over-riding significant factor in terms of fluorosis of esthetic concern was exposure to water fluoridation in infancy in both unadjusted and adjusted models.

CONCLUSIONS

The important factor in relation to fluorosis of esthetic concern was explained by exposure to fluoridated water in infancy, and was not explained by age, sex, level of parental education or early childhood oral health behaviors. However, prevalence of this condition was relatively low. These findings should inform policies on appropriate total fluoride exposure levels during infancy.

Comparison of salivary fluoride levels following use of dentifrices containing different concentrations of fluoride

Many industrialized countries have reported a decline in caries prevalence over the past few decades. These reductions have been related to the regular use of fluoride dentifrices. Fluoride dentifrices are the most cost-effective and efficient means of caries prevention. However, there have been concerns regarding the risk of fluorosis in children due to the ingestion of dentifrices. This has led to the use of dentifrices with low concentration of fluoride. Salivary fluoride levels after tooth-brushing have been shown to be related to the anticaries efficacy of fluoride dentifrices. The present study was designed to evaluate the effect of the concentration of fluoride in the dentifrice, on the salivary fluoride level in children. Twenty children in the age group of five to six years were randomly selected and divided into two groups using, either 500ppm or 1000ppm fluoride dentifrice (sodium monofluorophosphate). Salivary fluoride levels at 0, 15, 30, 45, 60, minutes after brushing were estimated. The data collected was statistically evaluated using the unpaired t-test. The results showed that salivary fluoride levels following use of 500ppm fluoride dentifrice were significantly lower than 1000ppm fluoride dentifrice. The low salivary fluoride levels may thereby reduce the anticaries efficacy. Hence, the pros and cons of recommending a low fluoride concentration dentifrice must be judiciously considered.

Influence of Fluoride Dentifrice on Brushing Abrasion of Eroded Human Enamel: An in situ/ex vivo Study

This in situ/ex vivo study assessed the effect of fluoride dentifrice on eroded enamel subjected to brushing abrasion. In a crossover study performed in 2 phases, 10 volunteers wore acrylic palatal appliances, each containing 3 human enamel blocks. Dentifrice was used to brush the volunteers' teeth and the specimens subjected to abrasion. In phases A and B the dentifrices used had the same formulation, except for the absence or presence of fluoride, respectively. The blocks were subjected to erosion by immersion of the appliances in a cola drink for 5 min, 4 times a day. Then the blocks were brushed, and the appliance was replaced into the mouth. Enamel alterations were determined using profilometry and percentage change in surface microhardness (%SMHC) tests. The data were tested using the paired t test. The mean wear values (+/-SD, microm) were: group A 6.84 +/- 1.72 and group B 5.38 +/- 1.21 (p = 0.04). The mean %SMHC values (+/-SD) were: group A 54.6 +/- 16.2 and group B 45.7 +/- 6.8 (p = 0.04). Fluoride dentifrice had a protective effect on eroded enamel subjected to brushing abrasion.

A comparison of two chlorhexidine gel brushing regimens and a conventional toothpaste brushing regimen for the development of tooth staining over a 6-week period

AIMS

A single-centre, randomized single-blind parallel study was undertaken to compare staining seen with three brushing regimens and to determine subject perception of side effects such as staining and effects on taste.

METHODS

This 6-week parallel study used 157 volunteers who were randomized into one of three treatment groups: (i) brushing in the morning and evening with a normal dose of a 1% chlorhexidine gel, (ii) brushing with a low dose of chlorhexidine gel in the evening and a whitening dentifrice in the morning, and (iii) brushing with a standard fluoride paste in the morning and evening. Following home usage of their allocated products, the study volunteers returned after 3 and 6 weeks to record the amount of stain present. After the 6-week period, subject perception of taste and stain acceptability was determined using a questionnaire.

RESULTS

After 6 weeks of use of the low-dose chlorhexidine gel and whitening dentifrice, significantly more stain was seen compared with the use of a standard dentifrice (P<0.0001). Similarly, significantly more stain was seen with use of the normal-dose chlorhexidine gel compared with the low-dose gel and whitening dentifrice (P=0.0007). Approximately 30% of individuals on the low-dose chlorhexidine gel regimen found the amount of stain unacceptable and 10% noted an effect on their taste perception.

CONCLUSIONS

The use of low dose of chlorhexidine gel at night and a whitening paste in the morning produced a significant amount of stain that 30% of subjects considered unacceptable.

[Contact allergy in the mouth]

Contact allergy is not frequently seen in the oral mucosa. Oral lichenoid reactions in conjunction with dental restorations, particularly amalgam fillings, are among the most common affections. Subjective symptoms such as burning mouth syndrome, could have an allergic component, but the etiology is unclear and complex. Food additives and oral hygiene products can cause oral lesions of allergic nature. Patch testing is the routine diagnostic tool used by dermatologists, though the interpretation of the clinical relevance is crucial.

Fluoride dentifrice ingestion and fluorosis of the permanent incisors

BACKGROUND

Fluoride dentifrice is a primary means of preventing childhood caries, but it is also an important risk factor for fluorosis. The authors examine the influence of fluoride dentifrice ingestion on fluorosis of the permanent incisors.

METHODS

Participants in the Iowa Fluoride Study received questionnaires at regular intervals concerning fluoride sources. The authors assessed fluorosis using the fluorosis risk index. They estimated daily fluoride ingestion from dentifrice, diet and fluoride supplements and divided the amount by kilograms of body weight. The statistical analysis related fluoride ingestion to fluorosis in the permanent incisors.

RESULTS

In bivariate analyses, mild fluorosis was significantly related to ingestion of fluoride dentifrice at ages 24 and 36 months (P = .02 for both). After the authors adjusted for fluoride ingested from dietary sources, logistic regression showed a significant association between fluorosis and dentifrice ingestion at age 24 months (P = .04).

CONCLUSIONS

The study results suggest that fluorosis of the permanent incisors is influenced by ingestion of fluoride dentifrice during the first three years of life. Further research is needed to assess total intake of fluoride as a risk factor for fluorosis.

CLINICAL IMPLICATIONS

These results support recommendations that young children use only a pea-sized amount of dentifrice. Parents should supervise young children as they brush their teeth with fluoride dentifrice.

Brushing effect of abrasive dentifrices during at-home bleaching with 10% carbamide peroxide on enamel surface roughness

During tooth bleaching abrasive dentifrices might change the outer superficial enamel. The aim of this in vitro study was to evaluate the roughness of human enamel exposed to a 10% carbamide peroxide bleaching agent at different times and submitted to different superficial cleaning treatments. The study consisted of 60 sound human enamel slabs, randomly assigned to different treatment groups: G1--not brushed; G2--brushed with a fluoride abrasive dentifrice; G3--brushed with a non-fluoride abrasive dentifrice; and G4--brushed without a dentifrice. There were 15 enamel slabs per group. Slabs of molar teeth were obtained and sequentially polished with sandpaper and abrasive pastes. A perfilometer was used to obtain the mean of Ra value on the surface of each specimen to initial and experimental times. Bleaching was performed on the enamel surface for six hours daily. After that, each slab received a cleaning surface treatment and was stored in artificial saliva. Analysis of variance (ANOVA) and Tukey's HSD hoc analysis (alpha =0.05) revealed significant differences in roughness values over time for enamel bleached and treated with different superficial cleaning methods. G1 and G4 showed no significant differences in roughness over time, G2 and G3 showed a significant increase in the surface roughness values. This in vitro investigation showed the sole use of 10% carbamide peroxide did not alter the enamel surface roughness, but the cleaning treatments that employed the use of brushing with abrasive dentifrices resulted in a significant increase of enamel surface roughness.

Oral Hygiene Products and Acidic Medicines

Acidic or EDTA-containing oral hygiene products and acidic medicines have the potential to soften dental hard tissues. The low pH of oral care products increases the chemical stability of some fluoride compounds, favors the incorporation of fluoride ions in the lattice of hydroxyapatite and the precipitation of calcium fluoride on the tooth surface. This layer has some protective effect against an erosive attack. However, when the pH is too low or when no fluoride is present these protecting effects are replaced by direct softening of the tooth surface. Xerostomia or oral dryness can occur as a consequence of medication such as tranquilizers, anti-histamines, anti-emetics and anti-parkinsonian medicaments or of salivary gland dysfunction e.g. due to radiotherapy of the oral cavity and the head and neck region. Above all, these patients should be aware of the potential demineralization effects of oral hygiene products with low pH and high titratable acids. Acetyl salicylic acid taken regularly in the form of multiple chewable tablets or in the form of headache powder as well chewing hydrochloric acids tablets for treatment of stomach disorders can cause erosion. There is most probably no direct association between asthmatic drugs and erosion on the population level. Consumers, patients and health professionals should be aware of the potential of tooth damage not only by oral hygiene products and salivary substitutes but also by chewable and effervescent tablets. Additionally, it can be assumed that patients suffering from xerostomia should be aware of the potential effects of oral hygiene products with low pH and high titratable acids.

In vitro toothbrush-dentifrice abrasion of two restorative composites

BACKGROUND

Surface wear can be a problem with directly placed composites.

PURPOSE

This study evaluated the in vitro wear and surface roughness of two composites at different cycle intervals after being subjected to toothbrush-dentifrice abrasion.

MATERIALS AND METHODS

Twenty specimens of a microhybrid, Filtek Z250 (3M ESPE, St. Paul, MN, USA), and a nanofill composite, Filtek Supreme (3M ESPE), were prepared according to the manufacturer's directions. Each specimen was subjected to toothbrush-dentifrice abrasion (250 g vertical load) using a deionized water-dentifrice slurry (Close-Up, Lever Ponds Ltd., La Lucia, ZA) and toothbrush heads (Oral-B 40, Oral-B Laboratories, Delmont, CA, USA). A brushing sequence of 10,000, 20,000, 50,000, and 100,000 strokes was performed for all samples at a rate of 1.5 Hz. At baseline and each cycle interval, a surface profilometer was used to determine average surface roughness, Ra. At the same intervals, vertical loss of material was measured with a precision micrometer. Data were analyzed using repeated-measures analysis of variance at p value .05. Analyses with atomic force microscopy (AFM) and scanning electron microscopy (SEM) were also performed.

RESULTS

After 20,000, 50,000, and 100,000 cycles, Filtek Supreme showed less significant wear than Z250. Filtek Supreme demonstrated higher surface roughness than Z250 after 50,000 and 100,000 cycles. However, AFM and SEM images indicated a more uniform surface topography for Filtek Supreme than for Z250. Abrasion wear and surface roughness increased with each cycle interval for both materials.

CONCLUSIONS

Although the initial performance of both materials was similar, a greater number of brushing cycles revealed differences between the wear resistance and generated surface roughness of the materials.

CLINICAL SIGNIFICANCE

The wear resistance and roughness results of Filtek Supreme suggest that it is suitable for clinical use, mainly in areas that are more subject to abrasive wear, such as Class V restorations.

Evaluation of dentin abrasion during professional tooth cleaning in an in vitro model

OBJECTIVES

Professional tooth cleaning (PTC) may lead to loss of exposed dentin. The aim of the present study was to determine the absolute loss of dentin during PTC using various product combinations with an in vitro model.

MATERIAL AND METHODS

Dentin specimens (72) were randomly assigned to nine groups. In four groups each, prophy brushes and prophy cups were used in combination with four different abrasives (calcium pyrophosphate, pumice, Hawe cleanic, Nupro coarse). In the ninth group, a rubber cup with embedded fluoride and abrasives was used (pasteless prophy cup). The treatment time was 37 s. Surface loss was determined by profilometry.

RESULTS

The surface loss in the nine groups was as following: (1) brush/calcium pyrophosphate: 6.18 microm (a); (2) brush/pumice: 5.51 microm; (3) brush/Nupro coarse: 10.10 microm (b); (4) brush/Hawe cleanic: 1.88 (a, b); (5) prophy cup/calcium pyrophosphate 2.07 (c); (6) prophy cup/pumice: 6.07 microm; (7) prophy cup/Nupro coarse: 5.93 microm (c); (8) prophy cup/Hawe cleanic: 4.93 microm (c); (9) pasteless prophy cup: 11.86 microm (c). Groups with the same letter in parentheses are statistically significant different at p<0.05. In a pooled analysis, no statistically significant difference between brushes and prophy cups was found.

CONCLUSION

In the present study, the surface loss of about eight PTC procedures was simulated. Hence, the dentin loss ranged between 0.24 and 1.48 microm per PTC. Therefore, PTC does not seem to be a main factor in dentin loss.

Profilometric and Microradiographic Studies on the Effects of Toothpaste and Acidic Gel Abrasivity on Sound and Demineralized Bovine Dental Enamel

The objective of this study was to assess the abrasive effects of toothpastes and acidic F gels on sound and demineralized enamel. Pairs of enamel specimens were cut from bovine incisors, embedded in epoxy resin and polished. An artificial subsurface lesion of 80-90 microm depth was created in one specimen from each pair. The samples were covered with adhesive tape, thereby exposing the enamel for abrasivity testing. All samples were divided into six groups of 15 and brushed with a slurry (1:3) of F gel or toothpaste and human saliva. Brushing with water (control) or with slurry was carried out (16,000 strokes) using a medium toothbrush (load 275 g) mounted in a brushing machine. Abrasion was evaluated using laser profilometry, and was about 50% less on sound than on demineralized enamel (p < 0.001). In the latter, brushing with water (0.09 +/- 0.03 microm) or with fluoride-free gel (0.08 +/- 0.03 microm) resulted in negligible wear. With a medium-abrasive paste (1.76 +/- 0.85 microm) and an acidic F gel (2.48 +/- 0.72 microm), brushing abrasion was significantly greater (p < 0.001) than with a low-abrasive paste (0.84 +/- 0.38 microm). The greatest wear (16.6 +/- 10.8 microm) was observed with high-abrasive paste (p < 0.001), and here transversal microradiography revealed a complete loss of the pseudointact surface after brushing. In vitro formed caries-like lesions can be abraded (by toothbrushing) more easily than sound enamel; hence, initial white spot lesions should preferably be brushed with oral hygiene products of low abrasivity.

The effect of a dentifrice and mouth rinse combination containing amine fluoride/stannous fluoride on plaque and gingivitis: a 6-month field study

AIM

To examine the effect of amine fluoride/stannous fluoride (AmF/SnF(2))-containing dentifrice and mouth rinse on plaque formation and gingivitis as compared with habitual oral hygiene procedures with a regular sodium fluoride (NaF) dentifrice.

MATERIAL AND METHODS

In total, 22 general practices participated in this research project. The participants (N=281) were randomly assigned into two groups: the test group received an AmF/SnF(2) dentifrice-mouth rinse combination and the control group received a NaF-containing dentifrice. The patients were requested to brush twice daily for approximately 2 min. The subjects of the test group had to rinse additionally in the evening for 30 s with 10 ml of the mouth rinse.

RESULTS

Both groups started with comparable scores of plaque, bleeding and staining. At 6 months, the plaque scores were 0.95 for the AmF/SnF(2) group and 0.99 for the NaF group (decrease of 16% and 10%, respectively). Bleeding scores, although significantly different from baseline, did not show differences between the two regimes. At the end of the experimental period, the overall staining was more pronounced in the AmF/SnF(2) group (41%) than the NaF group (26%). Both plaque reduction and increase in staining seemed to be correlated to the amount of mouth rinse used in the test group.

CONCLUSION

In instruction-resistant patients recruited from dental practices, the combined use of AmF/SnF(2) did not decrease gingivitis at a significant level in comparison with the regular regime of two times daily brushing with an NaF-containing dentifrice. However, the above-mentioned combination resulted in greater plaque reduction than that observed with the use of the conventional dentifrice. When used according to the manufacturer's instructions, this effect on plaque scores was more pronounced.

Removal of root substance with the Vectortm-system compared with conventional debridement in vitro

OBJECTIVE

The aim of the present study was to assess the removal of root substance with the Vector-system depending on different irrigation fluids and to compare the results with conventional methods for root debridement.

MATERIAL AND METHODS

Forty extracted human teeth were treated using four different methods: Vector-system with polishing fluid and metal curette (VP), Vector-system with abrasive fluid and metal curette (VA), conventional ultrasonic system (U) with insert tip "P" and hand instrument. Treatment of the calculus-free root surfaces was carried out for a total of 12 min. using an artificial periodontal pocket. At intervals of 120 s, the removal of dental hard tissues was assessed using a three-dimensional (3D) laser scanning device and the Match 3D software with an accuracy of 0.00001 mm(3).

RESULTS

No difference in the removal of root substance with the hand instrument (0.0055 mm(3)/s) and the Vector-system using the abrasive fluid (0.0044 mm(3)/s) could be observed (p=0.51). Using these two systems, a larger amount of root substance (p<0.05) was removed compared with the other methods (U: 0.0023 mm(3)/s, VP: 0.0022 mm(3)/s), which did not differ from each other (p=0.76).

CONCLUSIONS

The present study indicates that the Vector-system in combination with polishing fluid or conventional ultrasonics might be used for root debridement without extensive root substance removal.

Brushing with and without dentifrice on gingival abrasion

OBJECTIVES

This study was designed to evaluate two factors possibly influencing incidence of gingival abrasion during toothbrushing: (1) the abrasiveness of a dentifrice and (2) the possible influence of feedback of oral sensory perception.

MATERIAL AND METHODS

For this purpose, two separate, single blind, randomized clinical experiments were performed. The two groups of subjects were requested not to brush their teeth 48 h, prior to the experiments. After staining with disclosing solution gingival abrasion sites were recorded as small (< or =5 mm) and large (>5 mm), both before and after brushing. The dentifrice experiment was a split-mouth design, including 36 subjects, brushing their teeth in two randomly selected contra-lateral quadrants, either with or without dentifrice, whereas the remaining two quadrants were brushed, using the alternative choice. The sensory perception feedback experiment was a full-mouth design, including 43 subjects and two separate brushing exercises with use of dentifrice. The first brushing-exercise was performed by a dental hygienist, excluding the feedback of oral sensory perception of the brusher. After a 4 weeks period of familiarization to the manual toothbrush, subjects brushed themselves in the same random order as the hygienist, using a fresh brush, thus including oral sensory perception.

RESULTS

In the dentifrice experiment, the increment of small abrasion sites was 5.86 for brushing with and 5.75 without dentifrice. There was no statistically significant difference between brushing with and without dentifrice. Both with and without dentifrice, more small abrasions were found vestibular, (3.78 and 4.22, respectively) as compared with lingual (2.22 and 1.42, respectively) (p=0.027, p<0.001). In the sensory perception feedback experiment, the increment in small gingival abrasion sites was larger for the subjects brushing themselves (8.86) as compared with the professional brushing (2.94, p <0.0001). Subjects caused more abrasion on the vestibular surfaces (6.28) as compared with the lingual (0.60, p=0.0001), where the professional did not show this difference (vestibular: 1.88, lingual: 1.30, p=0. 1388).

CONCLUSIONS

No statistically significant difference in the incidence of gingival abrasion was found between brushing with dentifrice or without dentifrice. Neither did oral sensory perception seem to affect the incidence of gingival abrasion.

The Effects of a Commercial Aluminum Airpolishing Powder on Dental Restorative Materials

INTRODUCTION

JET-Fresh (Dentsply International, York, PA), a new airpolishing powder that contains aluminum trihydroxide as the abrasive agent, has been introduced for use with Prophy-Jet trade mark (Dentsply International).

PURPOSE

The aim of this study was to investigate the surface effects of aluminum trihydroxide airpolishing powder on a series of restorative materials.

MATERIALS AND METHODS

A total of 6 Class V preparations with enamel margins were created on the buccal surface of extracted human molars. The preparations were restored with Type III gold, a high copper spherical alloy amalgam, porcelain, a light-activated hybrid composite material, a light-activated microfilled composite material, and a light-activated, resin-modified glass ionomer material. The distal half of each restoration was covered with fiberglass tape and the mesial half subjected to treatment with the aluminum trihydroxide powder via the Prophy-Jet for 5 seconds. After removal of the protective tape, the buccal surface of each treated tooth was replicated with impression material. Replicas were generated using epoxy resin and prepared for evaluation with scanning electron microscopy.

RESULTS

The aluminum trihydroxide produced surface alterations that were apparent visually and when viewed by a scanning microscope of the hybrid and microfilled composites and the glass ionomer restorations. The surfaces of the amalgam and gold restorations were altered, but not to the extent that the resin-based materials were. No disruption of the surface characterization of the porcelain was detected; however, with gold and porcelain materials, the aluminum trihydroxide removed notable amounts of the luting cements (the results are consistent with the data gathered with sodium bicarbonate powder).

CONCLUSION

Aluminum trihydroxide as the abrasive agent in an airpolishing system should be avoided on resin composites, resin-modified composites, and around the margins of cemented restorations.

An in situ Investigation into the Abrasion of Eroded Dental Hard Tissues by a Whitening Dentifrice

This crossover study aimed to investigate abrasion of previously eroded hard dental tissues by a whitening dentifrice compared to a regular dentifrice. After a 3-day lead-in period, 14 volunteers were randomly assigned to use one of the toothpastes while wearing a removable appliance, containing 3 enamel and 3 root dentine slabs on each side. On the first day salivary pellicle was allowed to form. Twice daily for the following 3 days, one side of each appliance was immersed in an acidic carbonated drink ex vivo while the other side remained unexposed. Specimens were then brushed with the allocated dentifrice. After a 3-day washout period, new sets of enamel and dentine slabs were mounted in the appliances and the participants commenced period 2 using the alternative toothpaste. Acid-treated specimens always showed more wear than untreated specimens. The whitening dentifrice did not significantly increase the wear of softened enamel compared with the regular dentifrice. Brushing with the whitening toothpaste led to significantly greater wear of sound enamel and of both eroded and sound dentine than the regular dentifrice. The results suggest that whitening dentifrices may not increase the wear of acid-softened enamel but may have a more deleterious effect on dentine than regular toothpastes.

[The comparative study of the effect of silica and calcium carbonate based dentifrice on dentine abrasives in vitro]

PURPOSE

To evaluate the effect of Silica (SiO(2)) and Calcium Carbonate (CaCO(3)) based dentifrice on their dentine abrasives.

METHODS

Microscope, environmental electron scanning electron microscope (SEM) and radioactive Dentine Abrasion (RDA) assay were used to quantitatively measure the wear of dentine.

RESULTS

The mechanical brushing assay showed severe dentine abrasion with CaCO(3) based dentifrices. There were only minor scratches on the specimens brushed with SiO(2) dentifrices. Analysis of the thin section by SEM after exposure to dentifrices showed that NaF/SiO(2) produced significant remineralization whereas MFP/CaCO(3) system resulted in little remineralization. RDA values were 86.17 and 98.61 for SiO(2) based dentifrices and 222.85 and 253.84 for CaCO(3) based dentifrices, respectively. The morphology of the irregular shaped CaCO(3) with sharp points/edges further explained the brushing and RDA results.

CONCLUSION

These results indicate that abrasive in dentifrice, e.g. CaCO(3), can cause severe abrasion of dentine in vitro.

Toothbrushing with vegetable oil: a clinical and laboratorial analysis

The dentifrices currently available in the marketplace contain many anticariogenic substances, fluoride and abrasives aimed to better clean the dental surface, remove dental plaque, improve salivary flow and its buffer capacity and reduce colonies of bacteria such as S. mutans, the causative agent of dental caries. The objective of this study was to evaluate the possibility of adequately removing dental plaque using an experimental almond oil dentifrice (Titoil) with no abrasives or antiplaque agents. This study was carried out with 80 volunteers, all of them 18-year-old recruits from the military training school of Araçatuba - SP. Saliva sampling and dental plaque disclosing were undertaken both before and after 28 days of toothbrushing with a low abrasive dentifrice (Group 1: 40 volunteers) or with Titoil (Group 2: 40 volunteers). Statistical analysis of the results revealed that the experimental dentifrice (Titoil) did not interfere with salivary flow and reduced dental plaque more than the low abrasive dentifrice, improved the salivary buffer capacity and decreased salivary S. mutans (Caritest-SM) as much as regular dentifrices. It was concluded that if the dental industry replaces abrasive by vegetable oil in dentifrices, these will be more effective in maintaining oral health and will cause less dental abrasion.

An in situ model to study the toothpaste abrasion of enamel

OBJECTIVES

In order to understand the clinical relevance of dentifrice abrasivity on the dentition in vivo, an in situ enamel wear model has been developed.

MATERIALS AND METHODS

Polished human enamel blocks were indented with a Knoop diamond, attached to dentures and worn by adult volunteers for 24 h per day. The blocks were brushed for 30 s, twice per day with dentifrices of known relative dentine abrasivity (RDA) and relative enamel abrasivity (REA). The dentifrices used were either dentifrice A (RDA=85, REA=3.4), dentifrice B (RDA=189, REA=2.0) or dentifrice C (RDA=132, REA=42.7). After 28 days, the blocks were removed and the geometry of each Knoop indent was remeasured. From the baseline and post-treatment values of indent length, the amount of enamel wear was calculated from the change in the indent depth.

RESULTS

The median values for enamel wear of dentifrices A, B and C were -0.02, 0.01 and -0.48 microm, respectively. The differences between dentifrice C and dentifrices A and B were of statistical significance.

CONCLUSION

This study has demonstrated the usefulness of an in situ technique for investigating the relationship between the abrasivity of a dentifrice in vitro and the wear of enamel in situ.

Abrasion of eroded root dentine brushed with different toothpastes

This study evaluated the surface roughness change and wear provided by different dentifrices on root dentine previously exposed to erosive challenges. According to a randomized complete block design, 150 slabs of bovine root dentine (6 x 3 x 2 mm) were ground flat and polished. In an area of 4 x 3 mm on the dentine surface, specimens were submitted to five erosive/abrasive events, each one composed by: exposure to Sprite Diet or distilled water for 5 min, then to a remineralizing solution for 1 min, and simulation of 5,000 brushing strokes. Four dentifrices--regular (RE), baking soda (BS), whitening (WT) and tartar control (TC)--and distilled water (CO), used as control, were compared. Final texture and the wear depth were evaluated using a profilometer. ANOVA did not show significant interaction, indicating that the effect of dentifrices on both surface roughness change and wear did not depend on whether or not the dentine was eroded ( p>0.05). There was no difference between abrasion of eroded and sound dentine. The Tukey's test revealed that WT, BS and TC provided the highest increase in surface roughness differing from RE and CO. TC yielded the deepest wear of root dentine, whereas RE and CO, the shallowest. No significant difference in wear among BS, TC and WT were observed. Within the limitations of this study, the data showed that abrasion of both eroded and sound root dentine was dependent on the dentifrice used.

Effect of 0.02% NaF solution on enamel demineralization and fluoride uptake by deciduous teeth in vitro

The application of 0.02% NaF solution on teeth with a cotton swab instead of brushing with fluoride dentifrice has been suggested for young children to reduce the risk of dental fluorosis, but its anticariogenic effect has not been evaluated. Thus, we studied the in vitro effect of 0.02% NaF solution on enamel demineralization and fluoride uptake in deciduous teeth; non-fluoride dentifrice and fluoride dentifrice (1,100 mg F/g) were used, respectively, as negative and positive controls. The treatment with fluoride dentifrice was more effective in reducing enamel demineralization (p < 0.05) and on fluoride uptake by the enamel (p < 0.05) than the non-fluoride dentifrice and the 0.02% NaF solution. Data suggest that the alternative use of 0.02% NaF solution instead of fluoride dentifrice should be reevaluated especially if dental caries are to be controlled.

In vitro evaluation of human dental enamel surface roughness bleached with 35% carbamide peroxide and submitted to abrasive dentifrice brushing

The aim of this in vitro study was to evaluate the surface roughness of human enamel bleached with 35% carbamide peroxide at different times and submitted to different superficial cleaning treatments: G1 - not brushed; G2 - brushed with fluoride abrasive dentifrice; G3 - brushed with a non-fluoride abrasive dentifrice; G4 - brushed without dentifrice. Sixty fragments of human molar teeth with 4 x 4 mm were obtained using a diamond disc. The specimens were polished with sandpaper and abrasive pastes. A perfilometer was used to measure roughness average (Ra) values of the initial surface roughness and at each 7-day-interval after the beginning of treatment. The bleaching was performed on the surface of the fragments for 1 hour a week, and the surface cleaning treatment for 3 minutes daily. The samples were stored in individual receptacles with artificial saliva. Analysis of variance and the Tukey test revealed significant differences in surface roughness values for G2 and G3, which showed an increase in roughness over time; G1 and G4 showed no significant roughness differences. The bleaching with 35% carbamide peroxide did not alter the enamel surface roughness, but when the bleaching treatment was performed combined with brushing with abrasive dentifrices, there was a significant increase in roughness values.

Comparison of two dentifrices with respect to efficacy for the control of plaque and gingivitis, and with respect to extrinsic tooth staining: a six-month clinical study on adults

The objective of this six-month, double-blind clinical study, conducted in harmony with American Dental Association guidelines, was to provide a comparison between Colgate Total Toothpaste and Crest Gum Care Toothpaste with respect to their levels of efficacy for the control of supragingival dental plaque and gingivitis, and with respect to the levels of tooth staining associated with their use. Adult male and female subjects from the Edinburgh, Scotland area were entered into the study and stratified into two treatment groups which were balanced for age, sex, baseline Quigley-Hein Plaque Index scores and baseline Löe-Silness Gingival Index scores. Subjects received an oral prophylaxis, and were instructed to brush their teeth twice daily (morning and evening) for one minute with their assigned dentifrice, using a soft-bristled toothbrush. Examinations for plaque, gingivitis and extrinsic tooth staining were conducted after three months' and again after six months' use of the study dentifrices. One-hundred and nine (109) subjects complied with the protocol and completed the entire six-month clinical study. At both the three- and six-month study examinations, the Colgate Total Toothpaste group exhibited statistically significantly less plaque, gingivitis and extrinsic tooth staining compared to the Crest Gum Care Toothpaste group. At the six-month examination, the magnitude of these differences exceeded 18% for all six parameters measured (18.7% for Plaque Index, 60.5% for Plaque Severity Index, 22.2% for Gingival Index, 85.1% for Gingivitis Severity Index, 45.3% for stain intensity, and 46.3% for stain area). Thus, the results of this six-month clinical study support the conclusion that Colgate Total Toothpaste provides a statistically significant, substantive advantage in efficacy for the control of plaque and gingivitis over Crest Gum Care Toothpaste, while, at the same time, providing better control against the development of extrinsic tooth staining.

The use of sodium bicarbonate in oral hygiene products and practice

Early dentifrices contained natural ingredients, mostly in coarse particle form, and were quite abrasive. Salts, either sodium chloride, sodium bicarbonate, or a mixture of both, have also been used for tooth cleaning because of their ready availability and low cost. Because of both their relatively low intrinsic hardness and their high solubility, another advantage is low abrasivity. Their biggest disadvantage is a salty, unpalatable taste. Many modern dentifrices that contain sodium bicarbonate, either as the sole abrasive or one of several, disguise the saltiness with flavoring and sweetening agents. An almost inverse relationship exists between the percentage of baking soda in a dentifrice and its abrasivity. Sodium bicarbonate has no anticaries activity per se but is compatible with fluoride. In high concentrations, sodium bicarbonate is bactericidal against most periodontal pathogens. Most clinical studies have not found significant differences in periodontal response to baking soda as compared with other commercial dentifrices, probably because of its rapid clearance from the gingival sulcus. Sodium bicarbonate may not be the "magic bullet" for curing dental diseases, but its safety (if ingested), low abrasivity, low cost, and compatibility with fluoride make it a consummate dentifrice ingredient.

Clinical study to compare extrinsic stain formation in subjects using three dentifrice formulations

The purpose of this study was to compare the degree of extrinsic dental stain formed with the use of three dentifrices: (1) a new dentifrice formulation containing 5.0% potassium nitrate and 0.454% stannous fluoride in a silica base (Colgate Sensitive Maximum Strength Toothpaste, Colgate-Palmolive Co.); (2) a commercially available dentifrice containing 5.0% potassium nitrate and 0.243% sodium fluoride in a silica base (Sensodyne Fresh Mint Toothpaste, Block Drug Company, Inc.); and (3) a dentifrice containing 0.243% sodium fluoride in a silica base (Colgate Winterfresh Gel, Colgate-Palmolive Co.). A total of 121 participants were entered into the study and stratified into 3 balanced groups according to baseline mean Lobene Stain Index scores. A thorough dental prophylaxis was completed on each participant after completion of the baseline examination. The three groups were randomly assigned to use one of the three dentifrices. The groups were well balanced with regard to mean baseline stain index scores, gender, and tobacco habits. Participants were instructed to brush their teeth twice daily (morning and evening) for 1 minute with their assigned dentifrice and a commercially available soft-bristled toothbrush. Extrinsic dental stain examinations, which measured dental stain area and dental stain intensity, were conducted at baseline and 4 and 8 weeks. Examinations were conducted by the same dental examiner at each examination. After 4 and 8 weeks' use of the test dentifrices, there was no statistically significant difference regarding extrinsic stain formation with the use of any of the dentifrices. Thus, it can be concluded from this study that the use of a new formulation dentifrice containing 5.0% potassium nitrate and 0.454% stannous fluoride in a silica base will not result in a greater formation of extrinsic dental staining than that which is formed by two commercially available dentifrices not known to cause extrinsic dental stain.

[Fluorosis: diagnosis, risk assessment and epidemiology]

Fluorosis is the most widespread side-effect of fluoride use and appears as discrete white spots on the enamel up to severe enamel dysplasia. There are different techniques for scoring fluorosis in epidemiological surveys. In the literature there is no uniform way of selection of teeth and data processing. Fluorosis risk is determined by environmental factors such as water and food fluoride content as well as individual factors such as use (or misuse) of fluoride supplements and fluoridated oral hygiene products. In a group of Flemish schoolchildren, fluorosis prevalence is low and mainly related to use of fluoride supplements and toothpaste in childhood.

Comparative intraoral tolerance of sodium hexametaphosphate and pyrophosphate antitartar dentifrices

A randomized, controlled clinical trial was conducted to assess the relative acute oral tolerance of a novel, dual-phase, tartar control dentifrice containing 7.0% sodium hexametaphosphate (5% hexametaphosphate anion). In this 4-day study, 159 healthy adult volunteers were randomly assigned to the experimental sodium hexametaphosphate dentifrice or a marketed, single-phase, antitartar dentifrice control containing 5.0% ionic pyrophosphate. A detailed oral soft tissue examination and interview were conducted each day by blinded evaluators to elicit clinical signs and symptoms associated with ad libitum use of the assigned dentifrice. A total of 24 subjects (15% of the study population) had new symptoms/signs after baseline. By treatment, 9% of subjects in the sodium hexametaphosphate group had new findings, compared to 21% of subjects in the pyrophosphate group, and these groups differed statistically (p < 0.03, two-sided) with respect to occurrence. In addition, onset, severity, duration and clinical presentation were generally milder in the sodium hexametaphosphate group compared to the pyrophosphate control. Only one subject (in the pyrophosphate group) discontinued treatment early due to oral intolerance. In this study, the 7.0% sodium hexametaphosphate dentifrice was well-tolerated, with significantly fewer symptoms and superior overall tolerance compared to the marketed antitartar dentifrice control.

Effects of brushing with a dentifrice for sensitive teeth on tubule occlusion and abrasion of dentin

By using a dentifrice or toothpaste for sensitive teeth, the brushing-induced effects on dentinal tubule occlusion and abrasion of human sound dentin were investigated with a scanning electron microscope and a scanning laser microscope. The dentifrice contained diatomaceous earth and silica as abrasives and strontium chloride hexahydrate as an active ingredient. Thirty dentin pieces of human premolar teeth with an average of 20% occluded dentinal tubules were attached to resin plates and exposed to the oral cavities of five adult subjects for 2, 4, and 8 weeks. Brushing with and without dentifrice was performed 1 min per day, respectively. Brushing with the dentifrice gradually decreased the mean average of occluded tubules from about 91 to 77% during 2 to 8 weeks, although there were no significant differences among the individual values. However, the mean abrasive loss of the dentin surfaces brushed with dentifrice significantly increased from about 52 to 143 microm in depth. The brushed surfaces of the dentin showed a rough topography with numerous toothbrush scratches but no organic pellicle was found. On the other hand, brushing without dentifrice caused about 99% of the dentinal tubules to occlude in 2 and 4 weeks and 100% in 8 weeks. The brushed dentin surfaces at 8 weeks were entirely covered with organic pellicle containing fine mineral granules derived from saliva, and the abrasive loss was about 1.4 microm in mean depth. Such results indicate that brushing with abrasive dentifrices for sensitive teeth remarkably erodes dentin, and suggest that the brushing should cause the dentinal tubules to open again for a certain period of time.