Can toothpaste or a toothbrush with antibacterial tufts prevent toothbrush contamination?

BACKGROUND: Periopathogens and cariogenic species survive more than 48 hours on toothbrushes even under dry storage. This study examined a decontamination of toothbrushes by means of the bactericidal effect of different toothpastes or a special coating of the tufts. METHODS: Eight untreated periodontitis patients were professionally brushed, using a new toothbrush per quadrant and 3 different toothpastes containing either amine/stannous fluoride (AmF/SnF2), amine fluoride (AmF), or a mild surfactant as major antibacterial component (excipient), or no paste (C). The brushes were rinsed and stored dry at room temperature. At different time intervals, 4 tufts per toothbrush were processed for selective and non-selective culturing procedures. The protocol was repeated comparing AmF/SnF2 and C with 2 toothbrushes with coated tufts (coat1 and coat2). RESULTS: At baseline, C brushes (n = 16) harbored 10(7), 10(8), and 10(6) colony forming units (CFU) of aerobic, anaerobic, and black pigmented species, respectively. After 24 hours 10(6) CFU of aerobic and anaerobic species could still be cultured from 14 of the 16 brushes. Black-pigmented species remained detectable up to 4 hours; detection frequencies for Fusobacterium nucleatum and Streptococcus mutans at 24 hours were 5/16. With AmF/SnF2 and AmF toothpaste the number of adhering bacteria was already 2 log lower at baseline (P<0.05), but not for the excipient (0.5 log, P = 0.7). With AmF/SnF2 no vital species could be detected after 8 hours. AmF reduced the bacterial survival rate significantly more than the excipient, but less than AmF/SnF2 (P<0.05). The bactericidal effect of coat1 and coat2 was negligible when compared to C (P>0.20), and clearly inferior to the AmF/SnF2 paste (P<0.0001). After 24 hours these brushes still harbored >10(5) CFU. CONCLUSIONS: Toothpastes can significantly reduce contamination of toothbrushes, but their bactericidal activity is dependent on their composition. Coated tufts failed to limit the bacterial contamination.     

Contamination of a toothbrush with antibacterial properties by oral microorganisms

OBJECTIVES: The aim of this study was to examine the contamination and the survival rate of periodontopathic and cariogenic species on new toothbrushes with antibacterial properties (coated bristles with triclosan), after a single use in periodontitis patients. The decontamination effect of the use of toothpaste was also evaluated. METHODS: Ten patients, who consulted the Department of Periodontology, for treatment of chronic periodontitis, were selected. In each patient four different toothbrushes were used. Two quadrants, randomly selected, were each brushed using a different antibacterial toothbrush. In one of these two quadrants toothpaste was used. The same happened with the remaining quadrants, only with regular toothbrushes. After brushing, the toothbrushes were rinsed and stored in room temperature and a dry environment. After 0, 4 and 24h, four tufts, from each toothbrush, were cut and processed for selective and non-selective culturing techniques, followed by identification and quantification of all species found. RESULTS: Immediately after brushing the toothbrushes harbored a significant number of microorganisms, with no statistically significant difference between the two types of brushes (regular and antibacterial). The reduction of microorganisms from 0 to 4h after brushing was statistically significant (p<0.05). The difference was less obvious from 4 to 24h. When toothpaste was used, brushes harbored significantly (p<0.05) lower numbers of colony-forming units (CFU) compared to those without the use of toothpaste. CONCLUSIONS: The antibacterial toothbrush with triclosan coated tufts failed to limit the bacterial contamination. The toothpaste, on the other hand, significantly reduced the contamination of toothbrushes.     

The effects of toothpastes on the residual microbial contamination of toothbrushes

BACKGROUND: Contaminated toothbrushes have been shown to harbor and transmit viruses and bacteria. The authors conducted a study to evaluate the effect of a triclosan-containing toothpaste on the residual anaerobic microbial contamination of toothbrushes. METHODS: Twenty patients who had Type III or Type IV periodontitis participated in this study. One side of each of their mouths served as a control (no toothpaste). The teeth on the other side were brushed with a regular toothpaste or a triclosan-containing toothpaste. After the toothbrushes were allowed to dry in air for four hours, the authors placed the toothbrush heads in solution, dislodged the microbes from the brushes by vortexing and plated them in culture dishes. The authors anerobically incubated the culture dishes and determined the presence or absence of Prevotella species or Ps; Porphyromonas gingivalis, or Pg; and Actinobacillus actinomycetemcomitans, or Aa. RESULTS: The authors detected Aa and Pg on the control toothbrushes more frequently than they did Ps. This variation in isolation frequency was statistically significant by chi 2 analysis (P < .001). The authors compared the isolation frequency of the three test organisms between the control and regular-toothpaste groups, between the control and triclosan-containing--toothpaste groups, and between the triclosan-containing--toothpaste and regular-toothpaste groups. They found no significant intergroup differences in the isolation frequencies after using chi 2 analysis. CONCLUSIONS: Toothpaste use reduced the residual microbial contamination for two of three test organisms, but the lower isolation frequencies were not statistically significant. Further study in this area is indicated. CLINICAL IMPLICATIONS: Dental professionals should advise patients who have systemic, localized or oral inflammatory diseases to disinfect or frequently replace their toothbrushes.     

The microbial contamination of toothbrushes. A pilot study

Ten individuals were each supplied with a new toothbrush of the same type and brand, together with identical tubes of fluoridated toothpaste. After a three-week period, during which subjects were asked to follow their usual oral hygiene practices, the toothbrushes were collected and assayed for microbial contamination using a range of selective growth media. The total microbial load per toothbrush was found to be 10⁴ to 10⁶ colony forming units. Staphylococci were found on all toothbrushes and streptococci on all but one. These two genera were also quantitatively dominant. Candida, corynebacteria, pseudomonads and coliforms were identified in 70, 60, 50 and 30 per cent of toothbrushes, respectively. However, mutans streptococci, lactobacilli and black-pigmented Gram-negative anaerobic rods were not detected on any of the toothbrushes. For each individual, information on variables such as toothbrush rinsing practices and post-brushing storage methods and environment was collected. No obvious relationship between such variables and microbial load was apparent but it is suggested that more extensive studies are needed, taking into account additional parameters such as age and degree of toothbrush wear and the use of pre-brushing mouthwashes.     

A clinical trial testing the efficacy of an ionic toothbrush for reducing plaque and gingivitis

OBJECTIVE: This study was designed to assess the efficacy of an ionic toothbrush on reducing plaque and gingivitis. METHODOLOGY: Twenty first-year dental students were included in the study. Ten individuals were randomly assigned to use either an ionic or a conventional toothbrush. Two periods of 28 days each were used with each brush, with a wash-out period of 14 days. A calibrated examiner used the Quigley-Hein Plaque Index (QHI) and Gingival Bleeding Index (GBI) on six sites per tooth, on all teeth, both pre- and post-brushing. The examiner was unaware of the toothbrush used by the subjects. Means were calculated, and for intra and inter-group comparisons a paired sample t-test was used (alpha = 0.05). RESULTS: On buccal-lingual surfaces, both toothbrushes significantly reduced plaque; there was no statistically significant difference between the two toothbrushes (1.56 and 1.52 for ionic and conventional toothbrushes, respectively). In interdental spaces, an increase of QHI was detected for both brushes, but without significant differences between them. For the GBI on buccal/lingual surfaces, no significant differences were detected between toothbrushes. The GBI did not significantly change for either toothbrush on interdental surfaces during the study period. CONCLUSION: The ionic and the conventional toothbrushes did not present statistically significant differences on plaque and gingival bleeding reductions.     

The effects of load and toothpaste on powered toothbrush vibrations

OBJECTIVES: The primary cleaning action of powered toothbrushes is the motion of the bristles in contact with the tooth surfaces. The aim of this study was to use scanning laser vibrometry to determine the effects of load and toothpaste on the bristle vibration characteristics of four powered toothbrushes (Oral-B Sonic Complete; Oral-B Professional Care 8000 Series; Sonicare Elite and Ultrasonex). METHODS: Toothbrushes were initially scanned, with the laser vibrometer, under unloaded conditions to provide baseline readings. Toothbrushes were then assessed under loaded conditions (1.00 N and 2.00 N), with and without toothpaste, to observe the effect on bristle motion. RESULTS: Application of 1.00 N load significantly reduced the displacement amplitudes of all powered toothbrushes (p<0.003) except for the Sonicare (p>0.497). With toothpaste, 1.00 N load caused a significant decrease in vibration displacement amplitude for all brushes (p<0.0001). The application of 2.00 N, with and without toothpaste, significantly reduced all toothbrushes vibration displacement amplitude (p<0.0001). Under all investigation conditions, the Oral-B 8000 had the largest vibration displacement amplitude of the toothbrushes tested. CONCLUSIONS: Load and toothpaste significantly affected the performance of powered toothbrushes. Understanding why these factors affect certain toothbrush designs more than others may lead to toothbrushes being designed with greater clinical efficacy.     

Plaque removal with the uninstructed use of electric toothbrushes: comparison with a manual brush and toothpaste slurry

BACKGROUND: Individuals purchasing electric toothbrushes for the 1st time will mostly only have the manufacturer's instructional leaflet for information of usage. AIMS: This study was designed to simulate the 1st-time purchase and early use of an electric toothbrush with the aim of comparing plaque removal with a manual toothbrush. Secondary aims were to assess chemical plaque removal effects of a toothpaste slurry and to compare between 2 electric brushes which differed only in head speed. METHODS: A group of 16 dentate subjects participated in this single-examiner blind, randomised, crossover design balanced for residual effects. Subjects had "average" oral hygiene and had never used an electric toothbrush previously. 7 days prior to the study, all subjects received the slower oscillating rotating toothbrush under test to use at home as they wished. The test treatments were brushing with 2 oscillating rotating electric toothbrushes, a manual toothbrush and a rinse with a toothpaste slurry (3 g/10 ml water). On day 1 of each study period, subjects were rendered plaque-free, suspended oral hygiene and returned on day 5. Plaque was scored at baseline by index and area and after 30 s, 30 s (total 60 s) and 60 s (total 120 s) of the cleaning treatments. Washout periods were at least 2 1/2 days. RESULTS: Highly significant treatment differences were found between the 4 treatments because the toothpaste slurry was totally without effect. Analyses between the 3 brush treatments overall revealed no consistent significant differences. The data suggest that in the early days of electric toothbrush use, subjects perform no better than using a manual brush. CONCLUSIONS: The present study, taken with results from others showing greater benefits from the use of electric brushes, supports the idea that dental professionals should, where possible, provide advice and instruction in the use of such devices.     

Microbial contamination of toothbrushes with different principles of filament anchoring

BACKGROUND: The retention and growth of cariogenic microorganisms on toothbrushes pose a threat of recontamination. The authors to studied three species of oral microorganisms found at different places on toothbrush filaments. METHODS: The authors tested on patients 30 toothbrushes each of three different toothbrush types made by a single manufacturer. The toothbrushes were divided into three groups by type of construction: staple-set tufting (toothbrush A); in-mold tufting (toothbrush B); individual in-mold placement of filaments (toothbrush C). Subjects used the toothbrushes once under standardized conditions; the authors subsequently examined the brushes for the presence of Streptococcus mutans, lactobacilli and Candida species. The inspection was carried out at three time intervals after use. RESULTS: S. mutans was retained to the highest degree, followed by lactobacilli and finally by C. albicans. The authors found that the number of microorganisms on toothbrush types A and B did not reveal a significant difference either on examination immediately after use or after the toothbrushes had been dried for two hours or eight hours. The technique of individual in-mold placement of filaments made retention of microorganisms more difficult. The difference between the number of germs retained on toothbrush types A and C, as well as that between the number of germs retained on types B and C, was significant or even highly significant. CONCLUSIONS: The results show that toothbrushes made with the technique of individual in-mold placement of filaments appear to retain the least amount of microbial material. CLINICAL IMPLICATIONS: Owing to the fact that toothbrushes always are a possible source of microbial reinfection, the arrangement of the filaments within the head of the toothbrush is of great importance with regard to hygiene.     

A novel approach to controlling bacterial contamination on toothbrushes: chlorhexidine coating

Abstract: Purpose: This project was conducted to determine the effectiveness of chlorhexidine‐coated toothbrush filaments in reducing quantities of bacteria. Materials and methods: An Institutional Review Board (IRB)‐approved, two‐group, double‐blind, randomized, post‐test only study was conducted. Sixty‐four individuals utilized control and experimental toothbrushes, for 30 days. At the end of the study toothbrushes were returned and transported to the laboratory for analysis. Microorganisms were detached from the filaments by sonification and vortexing then plated on Mitis Salivarius (MS) (selective) and trypticase soy agar (TSA) 5% Sheep Blood (non‐selective) media. Inoculated plates were incubated aerobically for 24 h at 37°C. After incubation, bacterial colony‐forming units (CFU) were determined. Data were analysed using Wilcoxon and Kruskal–Wallis tests. Results: Fifty‐nine toothbrushes were returned for analysis; experimental (n = 31) and control (n = 28). Data from TSA media revealed a mean CFU for the control group of 5.41 × 10⁵ compared with 6.28 × 10⁵ for the experimental group. Data from MS agar resulted in a mean CFU for the control group of 4.32 × 10⁵ compared with 4.20 × 10⁵ for the experimental group. Conclusion: Results revealed no statistically significant difference in the quantity of bacteria surviving on toothbrush filaments between control and experimental groups, on both selective and non‐selective media, after 30 days.     

Efficacy of ultrasonic, electric and manual toothbrushes in patients with fixed orthodontic appliances

OBJECTIVE: This crossover study compared the efficacy of an ultrasonic toothbrush for the reduction of plaque, gingival inflammation, and levels of Streptococcus mutans, in relation to an electric and a manual toothbrush. MATERIALS AND METHODS: Twenty-one patients with orthodontic appliances were divided into three groups. All patients were evaluated by a periodontist and samples of saliva were collected for quantification of S mutans. The patients received their first brushes with appropriate instructions. For each crossover leg, patients used each toothbrush for a period of 30 days. At the end of each washout period, participants received a periodontal evaluation and new samples of saliva were collected. After 15 days of using their own toothbrushes, patients received the next toothbrushes in the experimental sequence. RESULTS: The ultrasonic brush group presented significant improvement in the reduction of visible plaque on the buccal surfaces (-6.36%, P = .007). The counts of S mutans decreased in the electric (2.04 x 10(5) to 1.36 x 10(5) colony-forming units [CFU]/mL) and ultrasonic (2.98 x 10(5) to 1.84 x 10(5) CFU/mL) groups. There were no statistical differences among the three brushes for the clinical and microbiological parameters evaluated. CONCLUSIONS: This study did not demonstrate that the ultrasonic toothbrush was better in reducing gingival inflammation in adolescent orthodontic patients, but plaque scores were lowered on buccal surfaces of teeth with orthodontic brackets. In addition, S mutans counts were markedly decreased in the electric and ultrasonic groups, which should be related to a reduced risk of oral disease.     

Influence of time,toothpaste and saliva in the retention of Streptococcus mutans and Streptococcus sanguinis on different toothbrushes

Objectives

The intraoral transmission of cariogenic and periodontopathogenic species seems to be facilitated by contaminated toothbrushes and other oral hygiene devices. The aim of this investigation was to analyze the in vitro retention and survival rate of Streptococcus mutans and Streptococcus sanguinis on different toothbrushes. The impacts of human saliva and antimicrobial toothpaste on these parameters were further evaluated.

Material and Methods

Part I: Four toothbrushes (Colgate 360°, Curaprox CS5460 ultra soft, elmex InterX, Trisa Flexible Head3) were contaminated by S. mutans DSM 20523 or S. sanguinis DSM 20068 suspensions for three minutes. Bacteria were removed from the toothbrushes after either three minutes (T₀) or 24 hours (T₂₄) of dry storage and grown on Columbia blood agar plates for the quantification of colony-forming units (CFUs). Part II: The effects of saliva from a caries-active or a caries-inactive person and of toothpaste containing 0.12% chlorhexidine digluconate were also tested.

Results

Part I: After three minutes of dry storage, approximately one percent of the bacteria were still detectable on the toothbrushes. After 24 hours, S. sanguinis exhibited a more pronounced decrease in viable cell numbers compared with S. mutans but the differences were not significant (Kruskal-Wallis test, p>0.05). Part II: The addition of human saliva from a caries-active or caries-inactive person slightly increased the retention of both streptococcal species at T₀. The use of toothpaste had no influence on the amount of viable streptococci at T₀, but it reduced the microbial load after 24 hours of storage. There were only slight nonsignificant differences (p>0.05) between the four toothbrushes.

Conclusions

In vitro bacterial retention and survival of S. sanguinis and S. mutans on different toothbrushes occurred. Within the limitations of this study, the use of human saliva or an antimicrobial toothpaste did not lead to significant differences in the microbial load on toothbrushes.     

Abrasion and stain removal by different manual toothbrushes and brush actions: studies in vitro

BACKGROUND AND AIMS: A limited amount of data using flat trim multitufted toothbrushes shows that abrasion of substrate surfaces by a standard toothpaste varies dependent on filament stiffness and configuration; soft brushes producing the most abrasion. The aims of these studies in vitro were to assess toothpaste abrasion of acrylic and stain removal by 5 proprietary medium toothbrushes with different head filament arrangements, and a prototype brush with rectangular filaments. The prototype brush had a medium texture in the long axis and soft texture at right angles to the long axis. MATERIAL AND METHOD: Optically clear acrylic was used as the substrate for abrasion by a standard toothpaste. Loss of substrate was determined by profilometry after 5000, 10000, 15000 and 20000 linear or rotary brushing actions. Stain removal was determined spectrophotometrically from optically clear acrylic specimens stained by chlorhexidine tea soaking sequences. Stained specimens were brushed with water using linear or rotary actions and measurements taken every 10 s to 60 s. RESULTS: Abrasion was progressive with increasing strokes and the pattern for each brush and brush action was to a first approximation linear. Overall, abrasion was significantly greater with linear compared to rotary action. Also overall brushes differed in the abrasion produced with both actions and particularly at greater exposure times. Within brush differences for the two motions were all significant by 20000 strokes except for the prototype brush. Stain removal was progressive over time with each brush but the pattern was non-linear. For the proprietary brushes the rotary motion removed less stain. For the prototype brush more stain was removed with the rotary action. Overall brushes differed significantly in stain removal within each motion and for each motion most differences between the proprietary and prototype brushes reached significance. CONCLUSIONS: The differences between brushes for both abrasion and stain removal must in large part relate to the filament contact area with the substrate surface. Whilst the model may not be predictive of clinical differences, it could find use to establish minimum criteria for toothbrush action.     

The role of the toothbrush in the abrasion process

To cite this article:
Int J Dent Hygiene 9 , 2011; 284–290
DOI: 10.1111/j.1601‐5037.2011.00505.x
Tellefsen G, Liljeborg A, Johannsen A, Johannsen G. The role of the toothbrush in the abrasion process. Abstract: Aim: To evaluate the relative abrasivity of different toothbrushes both qualitatively and quantitatively. Materials and Methods: Acrylic plates were exposed to brushing in a brushing machine with ten different toothbrushes with water alone and with a toothpaste. The results were evaluated using a profilometer after one and 6 h of brushing (corresponding to 2000 and 12 000 double strokes, respectively). A surface roughness value (Ra‐value) and also a volume loss value were calculated from the profilometer measurements. These values were then compared to each other. Results: The results showed that brushing with water alone caused less abrasion than when a toothpaste was added. Six‐hour brushing with water caused less abrasion than 1 h with a toothpaste. The number of filaments or filament diameter influenced the results in various ways. When brushing with water, the harder toothbrush (Jordan Medium) caused more abrasion (higher Ra‐value), but when adding the toothpaste, the softer toothbrush (Jordan soft) caused more abrasion after 12 000 double strokes. Conclusion: Besides supporting the fact that a toothpaste is needed to create a significant abrasion, this study also showed that a softer toothbrush can cause as much and in some cases more abrasion than harder ones. When conducting abrasivity studies, it is important to look at both the quantitative and qualitative aspect of abrasivity.     

Role of brushing technique and toothbrush design in plaque removal

Abstract – Twenty-four adults participated in an intraindividual crossover experimental study to compare the plaque removing ability of straight multitufted and V-shaped brushes. Twelve of the participants had loss of periodontal tissue resulting in open but healthy interdental areas while the other 12 displayed no periodontal breakdown. In part 1 the participants were asked to brush their teeth using their own brushing technique and length over two 12-day periods during which time they, at random, used one brush for the first and the other brush for the second period. In part 2 the participants were professionally brushed by two dental assistants using four brushing techniques (The Bass, The Roll, The Circular Scrub and The Horizontal Scrub) randomly assigned to the four quadrants of the mouth. Cleaning was performed once a day for two 5-day periods, during which time the participants refrained from brushing and interdental cleaning. Initial toothbrush assignment was randomized. At the beginning of the study and each test period no plaque or gingival inflammation was visible. At the end of each period the accumulated plaque was registered. The results showed that there was no difference between the two brushes tested in the unsupervised part. The plaque removing ability when using either of the brushes varied between participants. When professionally used the straight multitufted and V-shaped toothbrushes did not show any difference in plaque removal on buccal and lingual surfaces. Interproximally the V-shaped toothbrush was better at plaque removal than the straight one. However, plaque still remained after brushing with the V-shaped toothbrush, which indicates that toothbrushing always must be supplemented with interdental aids and that the shape of brushes as well as the techniques used are of little importance. Interproximal areas with tissue breakdown and loss of interdental papillae accumulated more plaque than those with no periodontal tissue breakdown.     

The plaque-removing efficacy of an oscillating/rotating toothbrush

Abstract The purpose of the present study was to test the effectiveness of a new type of BRAUN electric toothbrush (D5) in comparison with the traditional BRAUN electric toothbrush (D3) and to a manual toothbrush (M). For this study, 60 dental students were selected who had no previous experience with the use of an electric toothbrush. The study consisted of 3 experiments. Prior to each experiment, all students were asked to abstain from all oral hygiene procedures for at least 24 h. In Exp I, the efficacy of toothbrushing was studied when one of the investigators brushed the teeth of the students. No toothpaste was used in this first part of the study. In Exp II, the efficacy of brushing was evaluated when the brushing was carried out by the students themselves. In Exp III, the efficacy of the brushing was studied after the students had received a professional instruction and oral prophylaxis. The available time for the brushing amounted to a total of 2 min per mouth. The amount of dental plaque was evaluated by means of the Silness and Löe plaque index at 6 sites around the tooth. Results showed in Exp I that both electric toothbrushes proved to remove significantly more plaque than the manual toothbrush (M 78%; D3 85%; D5 86%). In Exp II, no significant differences in plaque-removing efficacy were found between the 3 brushes (M 73%; D3 72%; D5 73%). In Exp III, the D5 proved to remove significantly more plaque than the other two brushes (M 77%; D3 77%; D5 83%). In conclusion, within the limitations of this study, both electric toothbrushes showed that they have the ability to remove more plaque than a manual toothbrush. The D5 proved to remove more plaque than the D3 after professional oral hygiene instruction.     

Evaluation of a new toothbrush concept with regard to bacterial elimination

Abstract. The efficacy of a new toothbrush filament layout concept (Topix, Peridental, France) was compared to that of a standard vertical-tuft toothbrush. Bacterial and exogenous deposit elimination were used as parameters of efficacy. 30 dental surgery students look part in the study. Plaque index scores were calculated according to a pre-defined protocol. Imprints of the 6 anterior teeth were taken before and after brushing with the 2 types of brushes, without toothpaste or rinsing, Imprints were examined by scanning electron microscopy (SEM). 12 h after brushing, imprint examination revealed bacterial flora polymorphism and the amount of dental plaque accumulated at the cervical third zone of teeth. Automated quantification in this zone of exogenous bodies showed that after brushing with vertical-tuft and cross-tuft brushes, there remained 1.26 mm² and 0.83 mm² of dental plaque, squamae, and blood residues, respectively. The plaque index values correlated to scanning electron microscopic observations. There was no significant difference in terms of efficacy between the cross-tuft and vertical-tuft toothbrushes.     

Abrasion of eroded dentin caused by toothpaste slurries of different abrasivity and toothbrushes of different filament diameter

Objective

This study aimed to evaluate the impact of toothpaste slurry abrasivity and toothbrush filament diameter on abrasion of eroded dentin in vitro.

Methods

Eroded dentin samples (hydrochloric acid, pH 2.6, 15 s) were brushed with 40 strokes in an automatic brushing machine using manual toothbrushes with different filament diameter (0.15, 0.20 or 0.25 mm). The toothbrushes were applied with a control slurry free of abrasive particles (RDA-value 10) or toothpastes slurries with different abrasivity (RDA-values 20, 50 or 100). Each erosive–abrasive cycle was followed by storage of the dentin samples in artificial saliva for 3 h. After each 4 cycles, the samples were stored in artificial saliva for 15 h. After 60 cycles, dentin loss was measured by profilometry and statistically analysed by ANOVA and linear regression analysis.

Results

Dentin loss increased along with the RDA-value of the toothpaste slurries. The impact of the filament diameter on dentin loss was less evident compared to the RDA-value. However, toothbrushes with smaller filament stiffness caused higher dentin wear in all toothpaste slurry groups (RDA 20, 50 and 100) except for the paste-free control group (RDA 10).

Conclusion

Abrasion of eroded dentin increased along with the RDA-value of the toothpaste slurry and with decreasing filament diameter of the toothbrush.     

Frequency of gingival lesions after standardized brushing as related to stiffness of toothbrush and abrasiveness of dentifrice.

Abstract. This clinical trial was primarily designed to determine to what extent the stiffness of toothbrush bristles and the abrasiveness of dentifrices influence the degree of gingival erosion. Further, the plaque removing effectiveness of the toothbrushes and dentifrices tested was evaluated. 24 dental hygienist students with clinically healthy gingivae volunteered for the study. A "soft" toothbrush with a bristle thickness of 0.15 mm, a "hard" toothbrush with a bristle thickness of 0.23 mm and 2 dentifrices of different abrasiveness were used for the experiment. The 2 brushes were also used without a dentifrice. Prior to each examination the teeth of the test subjects were brushed by the same dental hygienist. Evident signs of laceration or ulceration at any 1 of 4 gingival aspects of each tooth were recorded as brushing injuries. The teeth were then stained with basic fuchsin and the amount of remaining plaque was assessed according to the PLQ Index (Bay & Ainamo 1974).
The use of the hard brush resulted in lower plaque scores and, at the same lime, more gingival erosions than the use of the soft brush. With both brushes a significantly greater number of lesions was recorded after use of an abrasive powder than when no dentifrice was employed. The difference in the amount of erosions occurring when utilizing either brush, without a dentifrice or with a moderately abrasive toothpaste, was not, however, found to be statistically significant. When assessed separately for the 2 brushes, the slight tendency towards lower PLQ scores with increasing abrasiveness of the dentifrice was not considered statistically significant. The study showed that the modest decrease observed in mean PLQ scores with increasing stiffness of the toothbrush bristles and with increasing abrasiveness of the dentifrice is accompanied by increased damage caused to the soft gingival tissues.     

The effect of periodontal therapy on the number of cariogenic bacteria in different intra-oral niches

Several publications have reported an increased susceptibility for root caries after periodontal therapy. It has been suggested that newly exposed roots were less resistant to cariogenic species. This study examined the hypothesis that the increased susceptibility could also be related to an intra-oral microbial shift during the initial phase of the periodontal therapy from a perio-pathogenic to a more cariogenic flora. 10 patients with severe periodontitis were followed for 8 months after thorough scaling and root planing in combination with optimal plaque control. At baseline and after 4 and 8 months, samples were taken from the saliva, the tongue dorsum and the supragingival interdental spaces. These samples were cultured both aerobically and anaerobically in order to determine the total number of colony forming units (CFU) per sample as well as the number of CFU of Streptococcus mutans and Lactobacillus species. Oral hygiene parameters were recorded at the same visits. Finally, at baseline and at the 8 months follow-up, changes in caries activity and periodontal health were registered. Although the total number of aerobic and anaerobic CFU in samples from the tongue and the saliva remained nearly constant over the entire observation period (variations within 0.5 log), significant (p< or =0.05) increases in the number of S. mutans could be detected, especially at month 8. The significant decrease in the total number of anaerobic CFU in samples from the teeth was not associated with a reduction in the number of S. mutans, so that also for this niche the relative proportion of the latter increased. The number of lactobacilli species for the different niches showed only negligible changes (within 0.5 log values), except for samples from the teeth for which a small (1 log), but statistically significant (p<0.01), reduction could be detected. The periodontal conditions improved for all patients, but the caries activity could not be arrested. These findings seem to indicate that the increased caries susceptibility after periodontal therapy might partially be explained by a significant increase in the number of S. mutans due to ecological changes within the oral cavity. The clinical consequence of this observation would be to advocate a more strict caries preventive program during initial periodontal therapy.     

Contamination of interdental brushes by periodontopathogens

Experimental studies have shown that intraoral transmission of bacteria can occur. Of course, the question arises as to how this transmission may happen. In this study, the contamination of interdental brushes by periodontopathogens is examined and compared to the microbial load of the periodontal pockets. In ten untreated chronic periodontitis patients, four interdental sites were professionally brushed with one interdental brush per patient. Subsequently, samples from the depths of the pockets (of the specific interdental sites) were obtained with paper-points. The interdental brush samples and the samples of the subgingival plaque, obtained by the pooled paper-points, were processed for dark-field microscopy examination as well as anaerobic culturing. The results showed that, although significant differences could be found between the brushes and paper-points with direct microscopy, the culturing did not uncover many differences. On the contrary, the detection frequencies of specific bacterial species were almost the same between the two. The total anaerobic colony-forming units (CFU), P. gingivalis, F. nucleatum, and E. corrodens found on the brushes showed a significant correlation with the subgingival plaque samples (P<0.005). These results suggest that, in untreated situations, interdental brushes are contaminated relatively easily by putative periodontopathogens in numbers comparable to their presence in periodontal pockets. This contamination could be a factor in the intraoral spread of bacteria.