Wegehaupt, Florian

Purpose: To investigate the approximal abrasive enamel and dentine wear using interdental brushes (IDBs) with and without toothpaste in a novel standardised in-vitro set-up. Materials and Methods: Seventy-two bovine enamel and 72 dentine specimens were prepared and randomly allocated into 12 groups (odd group: dentine; even group: enamel). The specimens were brushed with three IDB types of ISO 2 (Curaprox (CPS09, groups 1–4), Elmex (size 2, groups 5–8) and Circum (Circum 2, groups 9–12)) with artificial saliva or toothpaste slurry (Colgate Total Original). A custom-made brushing device simulated interdental brushing for 1 h on dentine (7,200 strokes) and 6 h on enamel (43,200 strokes). Wear was assessed using a contact profilometer, and electron microscopy images were taken. Kruskal–Wallis and Mann–Whitney tests were used for statistical analysis. Results: The combination of IDBs with artificial saliva resulted in enamel and dentine wear below the detection limit, similar to the enamel wear when toothpaste was used. Dentine specimens showed significant abrasive wear, which was influenced by the IDBs’ design as follows: Curaprox (median ± interquartile range (IQR): 8.6 ± 1.0 µm), Circum (9.7 ± 2.9 µm), and Elmex (18.8 ± 9.1 µm). The difference in wear between Curaprox and Circum was not statistically significant (P = 1). However, the increase in the wear of Elmex compared with that of the other IDBs was significant (P 0 0.001). Conclusion: The use of IDBs with toothpaste may cause statistically significant dentine wear and should not be recommended in combination. Appropriate instructions are essential. Keywords: abrasion, enamel, dentine, interdental brush substance loss

Purpose: This in-vitro study aimed to investigate the cleaning efficacy of 18 different manual children’s toothbrushes applying horizontal, vertical, and rotational movements, as well as to evaluate the rounding of their filament ends. Materials and methods: Models equipped with artificial teeth (coated with titanium dioxide) were brushed using a brushing machine with clamped manual children’s toothbrushes. The machine carried out horizontal, vertical, and rotational movements for 1 min with a constant contact pressure of 100 g. The percentage of the area of titanium dioxide removed from the buccal, mesial, distal and total surfaces of the artificial teeth corresponded to the cleaning efficacy. To assess the filament design, a scanning electron microscope was used to check the morphology of the filaments which was scored with Silverstone and Featherstone scale. SPSS 22 was used for data analysis. Results: The rotational and the vertical movements achieved the best cleaning efficacy with all tested toothbrushes. The vast majority of the tested toothbrushes had their poorest cleaning efficacy in the horizontal movement. Only a small part of the children’s toothbrushes (3 out of 18) had a correct and acceptable proportion of rounded bristle ends. Conclusions: Based on the present results, it could be concluded that the cleaning efficacy of different manual children’s toothbrushes varied considerably. The best cleaning efficacy was almost always observed for rotational and vertical movements. Keywords: children’s toothbrushes, cleaning, efficacy, filament end rounding, pediatric dentistry

Purpose: To investigate the impact of manual toothbrush usage duration and associated wear on cleaning performance in a tooth model with fixed orthodontic appliances. Materials and Methods: Black resin teeth with attached brackets were coated with a white layer of titanium dioxide and subjected to brushing using a brushing machine. Two distinct brushing motions, horizontal and circular, were tested. Following each brushing session, the percentage of cleaned areas (total and adjacent to the bracket) was measured to determine the cleaning performance of the toothbrushes. Usage was simulated using a 3D-printed tooth relief with brackets and wire. Cleaning performance was re-evaluated after simulated 2, 4, 6, 12, 18 and 24 months of usage, and toothbrush wear was quantified respectively. Results: Cleaning performance of all investigated brushing motions and tooth areas improved during the test period, although statistical significance was only reached for horizontal brushing. Furthermore, horizontal brushing proved more effective regarding total tooth area and the area adjacent to the bracket compared to circular brushing. Conclusion: This in-vitro data shows that toothbrushes may feature sufficient or even improved cleaning performance on teeth with orthodontic appliances even after 24 months. However, direct transferability into the clinical setting is limited, as in-vivo toothbrush wear is complex and depends on individual patient habits, and other factors might necessitate an earlier toothbrush change. Nevertheless, this study suggests that cleaning performance and thus oral hygiene in patients with orthodontic appliances may not be critically dependent on usage duration and visual appearance of the toothbrush itself. Keywords: oral hygiene, cleaning performance, toothbrush wear, orthodontic appliances

Purpose: This study investigated the effect of toothbrush bristle stiffness and brushing force on the cleaning efficacy in vitro. Materials and Methods: Eighty bovine dentin samples were allocated to eight groups (n=10). Two custom-made toothbrushes of different bristle stiffness (soft and medium) were tested at four different brushing forces (1, 2, 3 and 4 N). Dentin samples were stained in black tea and brushed (60 strokes/min) for a total of 25 min in a brushing machine with an abrasive solution (RDA 67). Photographs were taken after 2 and 25 min of brushing time. Cleaning efficacy was measured planimetrically. Results: After 2 min of brushing, the soft-bristle toothbrush did not cause statistically significantly different cleaning efficacy at different brushing forces, while the medium-bristle toothbrush cleaned statistically significantly less efficaceously only at 1 N. Comparing the two different toothbrushes, higher cleaning efficacy was observed only at 1 N for the soft-bristle brush. At 25 min brushing time, the soft-bristle cleaned statistically significantly better at 4 N compared to 1 N and 2 N and at 3 N compared to 1 N. Using the medium-bristle, cleaning efficacy increased with increasing brushing force. After 25 min of brushing, no statistically significant difference was observed between the two different toothbrushes. Conclusion: Irrespective the brushing force, the use of a soft or medium toothbrush results in comparable cleaning efficacy. At 2 min brushing time, increasing the brushing force does not increase the cleaning efficacy. Keywords: bristle stiffness, brushing force, cleaning efficacy, toothbrush

Purpose: To assess the root surface roughness and substance loss induced by chemical and chemomechanical challenges on root surfaces pretreated with ultrasonic instrumentation, a hand scaler, or erythritol airflow. Materials and Methods: One hundred twenty (120) bovine dentin specimens were used in this study. Specimens were divided into eight groups and treated as follows: groups 1 and 2: polished with 2000- and 4000-grit carborundum papers but not instrumented (‘untreated’); groups 3 and 4: hand scaler; groups 5 and 6: ultrasonic instrumentation; groups 7 and 8: erythritol airflow. Samples from groups 1, 3, 5, and 7 then underwent a chemical challenge (5 x 2 min HCl [pH 2.7]), whereas samples from groups 2, 4, 6, and 8 were subjected to a chemomechanical challenge (5 x 2 min HCl [pH 2.7] + 2 min brushing). Surface roughness and substance loss were measured profilometrically. Results: The least substance loss through chemomechanical challenge was noted after erythritol airflow treatment (4.65 ± 0.93 µm), followed by ultrasonic instrumentation (7.30 ± 1.42 µm) and the hand scaler (8.30 ± 1.38 µm); the last two (hand scaler and ultrasonic tip) did not differ statistically significantly. The highest roughness after chemomechanical challenge was observed on ultrasonically treated specimens (1.25 ± 0.85 µm), followed by hand-scaled specimens (0.24 ± 0.16 µm) and those subject to erythritol airflow (0.18 ± 0.09 µm); there was no statistically signficant difference between the latter two, but they both differed statistically significantly from the ultrasonically treated specimens. No statistically significant difference in substance loss through the chemical challenge was observed between specimens pretreated by the hand scaler (0.75 ± 0.15 µm), ultrasonic tip (0.65 ± 0.15 µm), and erythritol airflow (0.75 ± 0.15 µm). The chemical challenge smoothed the surfaces treated with the hand scaler, ultrasonic tip, and erythritol airflow. Conclusion: Dentin pretreatment with erythritol powder airflow resulted in a higher resistance to chemomechanical challenge than did dentin treated ultrasonically or with the hand scaler. Keywords: erythritol airflow, hand scaler, ultrasonic, substance loss, surface roughness

Purpose: To investigate the effect of the supplementation of energy drinks with green tea extract on abrasive and erosive dentin wear. Materials and Methods: Six groups, each comprising 15 bovine dentin samples, were prepared, yielding a total of 90 samples. Erosion was performed by immersing the samples in Red Bull and Red Bull light with and without green tea extract. Tap water with and without green tea extract was used as the control groups. The samples were subjected to abrasive/erosive cycling for five days. The following cycling was performed daily: toothbrush abrasion (20 brushstrokes; 2.5 N); eight erosive cycles (2 min storage in the respective solutions); in between the erosive cycles, storage in artificial saliva (60 min) and again toothbrush abrasion (20 brushstrokes; 2.5 N). During the night, samples were again stored in artificial saliva. Abrasive/erosive dentin wear was measured using a stylus profilometer (µm, accuracy = 40 nm). The measured dentin loss results from the vertical position shift on the y-axis from base to final profile after the wear process in 2D. Pairwise comparisons between the groups were carried out using Wilcoxon signed-rank test. Results: The following dentin wear (median [IQR]) was measured: Red Bull: 1.9 µm (0.5); Red Bull Light: 1.3 µm (0.3); Red Bull with green tea extract: 0.8 µm (0.3); Red Bull Light with green tea extract: 0.3 µm (0.5); Tap water with green tea extract: -0.2 µm (0.7); Tap water: -1.0 µm (1.2). The comparison of all tested groups to each other proved to be statistically significant (p < 0.05). Conclusion: The supplementation of energy drinks with green tea extract provide a protective effect against erosive/abrasive wear in vitro. Keywords: abrasive dentin wear, energy drinks, erosive dentin wear, green tea, profilometry

Purpose: To investigate the absolute wear caused by toothpastes with highly discrepant REA (Relative Enamel Abrasivity) and RDA (Relative Dentin Abrasivity) values on both enamel and dentin: Candida Peppermint (CP; REA: 1; RDA: 42), Colgate Total Original (CTO; REA: 4; RDA: 100), Signal White System (SWS; REA: 8; RDA: 143), and Candida White Diamond (CWD; REA 244; RDA: 12). Materials and Methods: Eighty (80) bovine enamel samples and 80 dentin samples were divided into four groups each (n = 20) and investigated after a 6-h brushing procedure (21,600 cycles, 60 cycles/min, load of 2.5 N) with the four toothpastes. The abrasive enamel and dentin wear were registered using a contact profilometer. The median and interquartile range (IQR) of the abrasive enamel and dentin wear were calculated for each group. Pairwise comparisons were conducted using the Wilcoxon signed-rank exact test, and the p-value was adjusted according to Holm (statistical significance set at 0.05). Results: CWD led to the highest abrasive enamel wear (9.86 μm [5.77]). CTO caused the highest abrasive dentin wear (166.70 μm [69.90]), being statistically significantly higher than the wear for CP (54.20 μm [24.00]) and CWD (17.00 μm [7.80]) (p = 0.00001). The abrasive dentin wear for CWD was statistically significantly lower in comparison to all other groups (p = 0.00001). Conclusion: Toothpastes with highly discrepant REA and RDA values presented statistically significantly different absolute wear on enamel and dentin. REA and RDA values should both be declared for every toothpaste. Keywords: abrasive dentin wear, abrasive enamel wear, RDA, REA, toothpaste abrasivity

Purpose: This in-vitro study deals with the question of whether the wear and tear of the manual toothbrush over a simulated timeframe up to 24 months has an effect on its cleaning performance. The purpose was to find indications as to whether and when a toothbrush needs to be replaced based on its cleaning performance. Materials and Methods: Models equipped with artificial teeth (coated with titanium dioxide) were brushed in-vitro using a brushing machine with clamped manual toothbrushes. The machine carried out even, horizontal brush strokes (120 brush strokes/min) for 1 min with a constant contact pressure of 2.5 N. The percentage of the area of titanium dioxide removed from the buccal, mesial and distal surfaces of the artificial teeth corresponded to the cleaning performance. The manual toothbrushes were used on bovine roots to simulate the wear and tear after 2, 4, 6, 12, 18, 24 months of use. The cleaning performance was re-evaluated after each simulated timepoint of wear. In addition, the brushes were photographed after each cycle.  Results: An increase in the in-vitro cleaning performance of the toothbrush was observed up to 6 months of wear compared to the starting point. After that, the cleaning performance decreased somewhat, but always remained above the initial cleaning performance. Conclusion: Based on the in-vitro cleaning performance after 24 months, the toothbrush would not have to be replaced. However, this in-vitro study cannot determine when a toothbrush should be replaced, because in-vivo it is also dependent on a variety of other factors such as fraying and microbial colonisation. Direct transfer of results from this study to everyday clinical practice is therefore difficult. Keywords: cleaning, performance, toothbrush, wear and tear

Purpose: To determine the salivary flow rate and subsequent dilution of toothpaste and assess the pH of oral fluids during toothbrushing with toothpastes of various pHs. Materials and Methods: The study was conducted as an in-vivo trial involving 30 healthy volunteers. The participants took part in a series of trials distributed over four appointments. After a screening check, in which the participants’ stimulated and unstimulated salivary flow rate and buffering capacities were determined, four test series involving toothbrushing were conducted. Participants brushed their teeth using a manual toothbrush for 2 min: once without toothpaste and three times using toothpastes of varying pHs. The salivary flow rate and subsequent dilution of the toothpaste was determined. Additionally, the pH of the collected oral fluid was analysed. Results: Brushing teeth with toothpaste caused a statistically significant increase in salivary flow rate (median/IQR in ml/min) (Elmex Kariesschutz 3.29/1.36, Colgate Total Original 3.23/1.08, Elmex Sensitive Professional 3.18/1.39) when compared to brushing teeth using a manual toothbrush without toothpaste (1.85/0.78) (p < 0.05). The variation in pH of the oral fluid samples was dictated primarily by the pH of the toothpaste used. Conclusion: The salivary flow rate when brushing using toothpaste was similar across all tested toothpastes, independent of pH, and had an average median of 3.23 ml/min. The dilution of 1 g of toothpaste during a standard toothbrushing procedure of 2 min is therefore approximately at a ratio of one part toothpaste to 6.5 parts saliva. Keywords: hydrogen ion concentration, saliva, salivary flow rate, toothbrushing, toothpastes

Der Beitrag befasst sich mit verschiedenen Hintergründen des gehäuft beobachteten Auftretens von Zahnerosionen bei Sportlern. Er fasst Grundlagen zur Entstehung von erosiven Zahnhartsubstanzdefekten sowie besondere ätiologische Faktoren für Sportlergruppen mit erhöhter Erosionsprävalenz zusammen und schließt mit Hinweisen zur Prävention. Keywords: Erosiver Zahnhartsubstanzverlust, Erosionen, Sportler, Risikofaktoren, Ernährung