A laboratory pilot study on voids in flowable bulk-fill composite restorations in bovine Class-II and endodontic access cavities after sonic vibration

This pilot study investigated whether sonic-powered application of a bulk-fill resin-based composite (RBC) in Class-II or endodontic access cavities reduces void formation. The crowns and roots of 60 bovine teeth with Class-II cavities (C) and endodontic access cavities (E) respectively, were assigned to ten groups (C1-C5, E1-E5). Cavities were filled with RBC (SDR flow + , one increment) using different application techniques: no adaptation (C1 + E1), spreading of RBC on the cavity surfaces with a dental explorer tip (C2 + E2), low (C3 + E3) or high frequency (C4 + E4) direct activation by inserting a sonic-powered tip into RBC and high frequency indirect activation with an ultrasonic insertion tip (C5 + E5). The restorations were light-cured and investigated for voids using microtomography. The number of voids and percentage of voids related to the volume were statistically analysed (α < 0.05). While most voids in Class-II restorations were observed in C4 (p ≤ 0.0031), no significant differences were found between the other groups (p > 0.05). The percentage of voids showed no differences in E1-E5 (p > 0.05). C4 showed a significantly higher percentage of voids compared to C2 (p < 0.001). There is no benefit in applying sonic vibration when filling Class-II or endodontic access cavities.

Effect of brushing force on the abrasive dentin wear using slurries with different abrasivity values

OBJECTIVE

The aim of this study was to investigate the resulting abrasive dentin wear using abrasive slurries with different RDA values and applying increasing brushing forces.

METHODS

Forty-five bovine incisors were randomly allocated in three groups (A, B, C, n = 15). One hundred and eighty dentin samples were prepared from these incisors and allocated to twelve groups (A1-A4, B1-B4, C1-C4; n = 15). The groups were subjected to a brushing cycle (120 strokes/min, 25 min) as follows: groups A1 to A4 with an abrasive slurry (RDA = 71) applying increasing brushing forces (1, 2, 3 and 4 N). Groups B1 to B4 were brushed using an abrasive slurry (RDA = 85) and C1 to C4 (RDA = 133) applying the same above-mentioned brushing forces. Abrasive dentin wear was recorded using a stylus profilometer and compared amongst the groups using robust models. Pairwise comparisons in each model were tested and corrected after Tukey's method (α = 0.05).

RESULTS

Applying 1-N brushing force resulted in the same amount of abrasive dentin wear in all groups regardless of the abrasivity of the used slurry. Increasing the brushing force to 2 N resulted in statistically significantly higher abrasive wear in all groups. This increase in abrasive wear was much higher when the slurry with high abrasivity was used (RDA = 133) compared with the lower abrasive slurry (RDA = 71).

CONCLUSION

The abrasivity of the used slurry does not add to the resulting abrasive wear when the brushing force is kept at 1 N. It seems better to advise and help the patients (showing signs of non-carious cervical lesions) calibrating their brushing force to 1 N, than only to advise them to use toothpastes with lower abrasivities.

Effect of tapered-end and round-end bristles on the abrasive dentine wear applying increasing brushing forces

OBJECTIVE

To investigate the effect of toothbrush bristles end configuration on the abrasive dentine wear at different brushing forces.

MATERIAL AND METHODS

One hundred and sixty bovine dentine samples were randomized into eight groups (n = 20). Groups (1 to 4) were brushed with tapered-end bristles at 1-, 2-, 3-, and 4-N brushing forces, respectively. Groups (5 to 8) were brushed with round-end bristles with the same brushing forces. The brushing sequence was carried out using an abrasive slurry (RDA = 121) for 25 min. Profiles were recorded using a contact profilometer. Mean and standard deviation were calculated for the abrasive dentine wear in each group. Two-way ANOVA was used to locate any significance. The significance values were corrected after Tukey (α = 0.05).

RESULTS

Brushing with tapered-end bristles resulted in statistically significantly less abrasive dentine wear than round-end bristles regardless of the applied brushing force (1 N: 4.4 ± 1.5 vs. 7.7 ± 2.0 µm; 2 N: 7.7 ± 2.1 vs. 12.2 ± 2.7 µm; 3 N: 11.3 ± 2.6 vs. 19.4 ± 3.7 µm; 4 N: 11.2 ± 2.1 vs. 25.3 ± 4.8 µm). The interaction between bristle configuration and brushing force was statistically significantly (p < 0.001).

CONCLUSION

Tapered-end toothbrushes might be a safer choice for patients, especially when showing signs of non-carious cervical lesion. However, other toothbrush properties should also be considered.

Effect of the toothbrush tuft arrangement and bristle stiffness on the abrasive dentin wear

The geometrical properties of toothbrushes play a role in developing abrasive tooth wear and non-carious cervical lesions. This study investigated the interplay between the toothbrush tuft arrangement (crossed vs. parallel) and bristle stiffness (soft vs. medium) on the abrasive dentin wear using three slurries with different levels of abrasivity (RDA: 67, 121 and 174). Twelve groups of bovine dentin samples (n = 20) were brushed with a combination of the aforementioned variables. Abrasive dentin wear was recorded with a profilometer and the resulting abrasive wear of each group was calculated and compared with each other using two-way ANOVA and pairwise tests. Toothbrushes with parallel tuft arrangement caused statistically significantly higher dentin wear compared to crossed tuft arrangement, regardless of the abrasivity level of the used slurry and the bristle stiffness. Soft crossed tuft toothbrushes caused statistically significantly higher abrasive dentin wear than medium crossed tuft toothbrushes, while soft and medium parallel tuft toothbrushes caused the same amounts of dentin wear, regardless of the RDA value of the used slurry. These results could be helpful for dentists and dental hygienists when advising patients. Crossed tuft toothbrushes could be a less-abrasive choice in comparison to parallel tuft toothbrushes.

OralDisk: A Chair-Side Compatible Molecular Platform Using Whole Saliva for Monitoring Oral Health at the Dental Practice

Periodontitis and dental caries are two major bacterially induced, non-communicable diseases that cause the deterioration of oral health, with implications in patients' general health. Early, precise diagnosis and personalized monitoring are essential for the efficient prevention and management of these diseases. Here, we present a disk-shaped microfluidic platform (OralDisk) compatible with chair-side use that enables analysis of non-invasively collected whole saliva samples and molecular-based detection of ten bacteria: seven periodontitis-associated (Aggregatibacter actinomycetemcomitans, Campylobacter rectus, Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola) and three caries-associated (oral Lactobacilli, Streptococcus mutans, Streptococcus sobrinus). Each OralDisk test required 400 µL of homogenized whole saliva. The automated workflow included bacterial DNA extraction, purification and hydrolysis probe real-time PCR detection of the target pathogens. All reagents were pre-stored within the disk and sample-to-answer processing took < 3 h using a compact, customized processing device. A technical feasibility study (25 OralDisks) was conducted using samples from healthy, periodontitis and caries patients. The comparison of the OralDisk with a lab-based reference method revealed a ~90% agreement amongst targets detected as positive and negative. This shows the OralDisk's potential and suitability for inclusion in larger prospective implementation studies in dental care settings.

Erosive tooth wear among athletes

The following article deals with various considerations concerning the frequently observed occurrence of dental erosion in athletes. It summarizes the basics of erosive tooth wear development as well as special etiologic factors for groups of athletes with increased prevalence of dental erosion and concludes with preventive advice. (Originally published (in German) in Quintessenz Zahnmed 2021;72:1008-1017).

Effect of toothbrush bristle stiffness and toothbrushing force on the abrasive dentine wear

Objective

To investigate the influence of toothbrush bristle stiffness and applied brushing force on the resulting abrasive dentine wear in vitro.

Methods

One hundred sixty bovine dentine samples were randomly allocated in eight groups (n = 20). Groups one to four were brushed with a soft‐bristle toothbrush with soft bristles applying 1, 2, 3 and 4 N brushing force, respectively. Groups five to eight were brushed with a medium‐bristle toothbrush applying the same aforementioned brushing forces (120 strokes/min, abrasive slurry (RDA = 121), 25 min). Profiles were recorded before and after the brushing sequence, and the median and interquartile range of abrasive dentine wear were calculated and compared using two‐way ANOVA and pairwise tests corrected after Tukey (α = 0.05).

Results

At 1, 2 and 3 N brushing force, the tested toothbrushes caused no significantly different abrasive dentine wear. At 4 N brushing force, the medium‐bristle toothbrush caused statistically significantly higher abrasive force than the soft‐bristle toothbrush. Using the medium‐bristle toothbrush, abrasive dentine wear statistically significantly increased with increasing brushing force from 1 to 3 N. However, increasing the brushing force to 4 N did not result in statistically significantly higher wear. Using the soft‐bristle toothbrush, abrasive dentine wear statistically significantly increased with increasing brushing force from 1 to 2 N. However, increasing the brushing force to 3 or 4 N did not result in statistically significantly higher wear.

Conclusion

The soft‐bristle toothbrush tends to cause less abrasive wear with increasing brushing force than the medium‐bristle toothbrush.

Effect of a sonic toothbrush on the abrasive dentine wear using toothpastes with different abrasivity values

Objective

This in vitro study aimed to investigate the effect of a sonic toothbrush on the resulting abrasive dentine wear using toothpastes with different abrasivities compared to the use of a manual toothbrush.

Methods

Ninety‐six bovine dentine samples were divided into six groups and subjected to a brushing sequence (sonic: 20 min, 0.9 N, 10 strokes/min; manual: 20 min, 1.6 N, 60 strokes/min) as follows: group 1: Elmex Sensitive Plus (RDA = 28) + manual toothbrush; group 2: Elmex Sensitive + sonic toothbrush; group 3: Elmex Kariesschutz (RDA = 65) + manual toothbrush; group 4: Elmex Kariesschutz +sonic toothbrush; group 5: Colgate Total Original (RDA = 121) + manual toothbrush; and group 6: Colgate Total Original +sonic toothbrush. The abrasive dentine wear was measured profilometrically.

Results

The median (IQR) abrasive dentine wear was as follows: Elmex Sensitive Plus (manual toothbrush: 2.7 µm (0.8), sonic toothbrush: 3.1 µm (1.9)); Elmex Kariesschutz (manual toothbrush: 4.9 µm (1.4), sonic toothbrush: 6.4 µm (2.1)); and Colgate Total Original (manual toothbrush: 5.2 µm (1.1), sonic toothbrush: 9.0 µm (3.1)). Differences in dentine wear between sonic and manual toothbrushes were statistically significant only in the groups brushed with Elmex Kariesschutz and Colgate Total Original (p ≤ 0.05).

Conclusion

Brushing with a sonic toothbrush could result in a higher abrasive dentine wear compared to manual toothbrush when combined with toothpastes with high abrasivity values.

Effect of dentin pretreatment on the resulting abrasive dentin wear

Background

This study aims to investigate the influence of different dentin pretreatment procedures on the resulting abrasive dentin wear.

Methods

Two groups (A, B) of 60 dentin samples each were prepared. Group A was brushed with an abrasive slurry (RDA = 85) and group B with a different abrasive slurry (RDA = 174). Four subgroups in each group (n = 15) were created (A1–A4) and (B1–B4). The subgroups were pretreated as follows: A1 + B1 with 1200-grit grinding paper, A2 + B2 with 1200- and 2000-grit papers, A3 + B3 with 1200-, 2000-, and 4000-grit papers, A4 + B4 with 1200-, 2000-, 4000-grit papers and with 1000 brushing strokes with a slurry of Elmex toothpaste. All samples were brushed for 25 min at 120 strokes/min. Abrasive dentin wear was measured for each sample profilometrically and the subgroups were compared with each other within the same group. Repeated measures one-way ANOVA was conducted to compare the subgroups and pairwise contrasts were estimated for multiple testing according to Tukey (α = 0.05).

Results

The resulting abrasive dentin wear in group A ranged between 15.3 ± 3.4 µm and 17.3 ± 5.5 µm and between 20.3 ± 6.8 µm and 22.5 ± 2.6 µm in group B. No statistically significant difference was noticed between any subgroups within the same group (p ˃ 0.05).

Conclusions

Different dentin pretreatment procedures do not affect the resulting abrasive dentin wear independent of the RDA value of the employed abrasive slurry.

Potential of different fluoride gels to prevent erosive tooth wear caused by gastroesophageal reflux

Background

This in-vitro-study aimed to evaluate the potential of different fluoride gels to prevent gastroesophageal reflux induced erosive tooth wear.

Methods

Surface baseline profiles of a total of 50 bovine enamel specimens [randomly assigned to five groups (G1–5)] were recorded. All specimens were positioned in a custom made artificial oral cavity and perfused with artificial saliva (0.5 ml/min). Reflux was simulated 11 times a day during 12 h by adding HCl (pH 3.0) for 30 s (flow rate 2 ml/min). During the remaining 12 h (overnight), specimens were stored in artificial saliva and brushed twice a day (morning and evening) with a toothbrush and toothpaste slurry (15 brushing strokes). While specimens in the control group (G1) did not receive any further treatment, specimens in G2–5 were coated with different fluoride gels [Elmex Gelée (G2); Paro Amin Fluor Gelée (G3); Paro Fluor Gelée Natriumfluorid (G4); Sensodyne ProSchmelz Fluorid Gelée (G5)] in the evening for 30 s. After 20 days, surface profiles were recorded again and enamel loss was determined by comparing them with the baseline profiles. The results were statistically analysed using one-way analysis of variance (ANOVA) followed by Tukey`s HSD post-hoc test.

Results

The overall highest mean wear of enamel (9.88 ± 1.73 µm) was observed in the control group (G1), where no fluoride gel was applied. It was significantly higher (p < 0.001) compared to all other groups. G2 (5.03 ± 1.43 µm), G3 (5.47 ± 0.63 µm, p = 0.918) and G4 (5.14 ± 0.82 µm, p > 0.999) showed the overall best protection from hydrochloric acid induced erosion. Enamel wear in G5 (6.64 ± 0.86 µm) was significantly higher compared to G2 (p = 0.028) and G4 (p = 0.047).

Conclusions

After 20 days of daily application, all investigated fluoride gels are able to significantly reduce gastroesophageal reflux induced loss of enamel.

Toothpastes with Enzymes Support Gum Health and Reduce Plaque Formation

Enzymes in toothpastes can support host immune responses, and thus maintain oral health. This study aimed to investigate gingival health and the plaque-reducing effects of enzyme-containing toothpastes. A laboratory study tested the antimicrobial potential of different enzyme-containing toothpaste formulations. Two promising formulations (enzyme-containing toothpastes with glucose oxidase and D-glucose with (C+) and without Citrox (C-) Citrox) were investigated in a clinical crossover trial (two slurries: sodium lauryl sulfate-containing (SLS), a toothpaste without SLS (reference), and water). Subjects (n = 20) abstained from toothbrushing for four days and rinsed with a toothpaste slurry. Bleeding on probing (BOP) and plaque indices (PI) were measured. A mixed linear model was used to statistically compare the slurries with respect to BOP and PI change. The in vitro bacterial growth-inhibiting evaluation showed the best results for SLS, followed by C+ and C-. The change in BOP and PI exhibited statistically significant differences to water rinsing (BOP; PI changes in % points (difference of the baseline and post-rinse values: water = 8.8%; 90.0%; C+ = -1.4%; 80.4%; SLS = 1.5%; 72.1%; reference = 0.8%; 77.5%; C- = -1.8%; 75.1%). All slurries exhibited anti-gingivitis and anti-plaque effects, resulting in a prophylactic benefit for limited-access regions during brushing.

[Assessment of dentists' opinions on the cause of failure of adhesive composite restorations]

Aim of this study was to get an overview of what dentists estimate to be the reason for failure of adhesive composite restorations and to gain knowledge about potential future foci for targeted further education. Therefore, a survey about the fabrication of composite restorations was conducted in the course of seven dental conferences with the main topic tooth-prevention. A total of 577 dentists participated in the survey. The most often called estimated factor for failure of composite restorations was the "dentist" (70.7%), followed by "indication" (32.2%), "material" (8.5%) and "patient" (8.1%). Participants estimated insufficient drying and fluid management (67.9%), incorrect application of the adhesive system (41.8%), insufficient lightpolymerisation (31.2%) and errors in incremental technique (27.6%) to be the main mistakes. The participating dentists claimed to attach great importance to careful drying and fluid management (60.8%), thorough adhesive application (37.3%), adequate incremental technique (32.6%) and sufficient lightpolymerisation (28.8%) while placing their own restorations. According to the survey participants, the treating dentist has the greatest influence on the quality and longevity of composite restorations. Drying and fluid management was the most often called estimated reason for failure but at the same time the step which is given the greatest caution.

Enamel Softening Can Be Reduced by Rinsing with a Fluoride Mouthwash Before Dental Erosion but Not with a Calcium Solution

PURPOSE

This in-situ-study investigated if rinsing the oral cavity with a calcium containing solution or a fluoride containing mouthwash immediately before an erosive attack leads to reduced enamel softening.

MATERIALS AND METHODS

Bovine enamel samples (n = 240) with measured baseline surface microhardness (KHN) were assigned to five series (S1-5). Twelve participants carried out each series as follows: Four enamel samples of the associated test series were placed in an intraoral appliance and carried in each participants' mouth. After 30 min, the participants either rinsed the oral cavity for 60 s with 30 ml of a solution prepared from a 1,000 mg calcium effervescent tablet dissolved in 100 ml water (S2), an 800 mg calcium containing mineral supplement powder (5 g) dissolved in 200 ml water (S3), a fluoride (500 ppm) mouthwash (S4), a fluoride (500 ppm) and stannous chloride (800 ppm) containing mouthwash (S5), or did not rinse with any test solution before the erosive attack (S1, negative control). The participants subsequently rinsed the oral cavity with 100 ml of a soft drink (Sprite Zero) for 60 s to simulate the erosive attack and immediately afterwards with water to stop the erosive process. As final step, surface microhardness was measured a second time and hardness loss (∆KHN) calculated. Differences of ∆KHN between the series were investigated by fitting a mixed effect model to the data set.

RESULTS

The highest loss of microhardness and thus softening of enamel (mean of ∆KHN; lower/upper confidence level) was observed in the negative control (S1: 60.2; 67.6/52.8). While no statistically significant difference (P > 0.05) compared to S1 could be found in S2 (50.0; 57.4/42.5) and S3 (54.6; 62.1/47.2), statistically significantly less softening of enamel (P < 0.001) was discovered in S5 (33.8; 41.2/26.4) and S4 (41.8.2; 49.3/34.4). S5 showed the overall lowest values for ∆KHN and thus best protection from enamel softening.

CONCLUSION

Rinsing with a fluoride mouthwash or a fluoride and stannous chloride containing mouthwash immediately before an erosive attack reduces the softening of enamel. None of the investigated calcium-containing solutions was able to reduce erosion induced softening of enamel.

Effect of Caries Infiltrant on Margin Integrity of Composite Fillings Placed Adjacent to Demineralised Primary Enamel

PURPOSE

To investigate the influence of pretreating demineralised enamel with an infiltrant on the margin integrity of Class V like composite restorations on primary teeth bonded with different adhesives.

MATERIALS AND METHODS

Forty specimens from primary molars were demineralised and circular class-V-like cavities were prepared. The cavities were treated with a universal adhesive (Scotchbond Universal Adhesive, 3M Oral Care), applied either in self-etch (SE) or etch-and-rinse mode (ER) mode. In groups SE-I and ER-I, the demineralised margins were pretreated with a caries infiltrant (Icon, DMG) prior to adhesive application. The cavities were restored with a nanofilled composite material and thermocycled. Marginal integrity was evaluated using SEM, and the percentage of continuous margin was statistically analysed.

RESULTS

Specimens treated with the caries infiltrant followed by the adhesive showed similar marginal continuity as the adhesive alone.

CONCLUSIONS

Pretreatment of demineralised primary enamel with a caries infiltrant before applying a universal adhesive does not influence the marginal integrity of composite fillings.

Green Tea Extract Reduces the Erosive Dentine Wear Caused by Energy Drinks In Vitro

PURPOSE

To investigate the effect of energy drinks supplementation with green tea extract on the erosive dentine wear.

MATERIALS AND METHODS

Six groups of bovine dentine samples (n = 15) were subjected to four cycles erosive attacks (10 min, 25 °C) and remineralisation (artificial saliva, 60 min, 37°C) using the following formulas: tap water; green tea extract; Red Bull; Red Bull supplemented with green tea extract; Red Bull Light; Red Bull Light supplemented with green tea extract. The erosive dentine wear - ie, the irreversible dentine loss - was measured using a stylus profilometer (µm, accuracy = 40 nm).

RESULTS

Median and interquartile range (IQR) of erosive dentine wear for the tested energy drinks before and after the supplementation with green tea extract were calculated as follows: Red Bull (before: 3.3 µm (1.0)); after: 1.2 µm (0.6)); Red Bull Light (before: 3.3 µm (0.9)); after: 2.0 µm (0.4)). The difference between the groups before and after the supplementation was statistically significant (P ˂0.05). The erosive dentine wear for the tap water group was calculated at 0.4 µm (0.6) and for the green tea extract group at -1.0 µm (1.3).

CONCLUSIONS

Supplementation of energy drinks with green tea extract could reduce the erosive dentine wear caused by energy drink in vitro.

Effects of Additional Use of Bioactive Glasses or a Hydroxyapatite Toothpaste on Remineralization of Artificial Lesions in vitro

OBJECTIVES

This in vitro study aimed to evaluate and compare the effect of two different bioactive glasses, a hydroxyapatite-containing, fluoride-free toothpaste (HTP) and a fluoride toothpaste (FTP) on the remineralization behavior of initial caries lesions.

MATERIALS AND METHODS

A total of 100 bovine enamel samples were randomly allocated to five groups of 20 samples each: NC = negative control group (artificial saliva); HTP = HTP group (Karex); FTP = FTP group (Elmex caries protection, 1,400 ppm); FTP + BGnano = FTP followed by Actimins bioactive glass; FTP + BGamorph = FTP followed by Schott bioactive glass. Radiographic documentation (advanced transversal microradiography; aTMR) was applied before and after all samples were exposed to a demineralizing gel for 10 days. Over a period of 28 days, samples were covered twice a day (every 12 h) with a toothpaste slurry of the respective test group or with artificial saliva in NC for 60 s and brushed with 15 brushing strokes. Samples in FTP + BGnano and FTP + BGamorph were additionally treated with the respective bioactive glass slurry for 30 s after brushing with the FTP. In the meantime, all samples were stored in artificial saliva. After 28 days, the structure of all samples was assessed again using aTMR and compared to the values measured after demineralization. The statistical evaluation of the integrated mineral loss was performed using Kruskal-Wallis test followed by a post hoc Conover test.

RESULTS

The FTP revealed the significantly highest increase of mineral content while the HTP showed the significantly lowest remineralization. Compared to artificial saliva, the use of the HTP or the combined application of FTP followed by bioactive glasses (FTP + BGnano and FTP + BGamorph) showed no significant remineralization.

CONCLUSION

Under remineralizing in vitro conditions, brushing with 1,400 ppm FTP induced significantly more remineralization compared to storage in artificial saliva. The additional administration of both bioactive glasses as well as the substitutional brushing with an HTP resulted in significantly less remineralization compared to brushing with 1,400 ppm FTP.

Erosive/Abrasive Enamel Wear While Using a Combination of Anti-Erosive Toothbrush/-Paste

PURPOSE

To investigate dental enamel wear caused by erosion and abrasion while using a combination of anti-erosive toothbrush/-paste.

MATERIALS AND METHODS

A total of 60 enamel specimens from bovine incisors were randomly assigned into five groups of 12 specimens each (G1-5, n = 12): (G1) control group (no treatment), (G2) standard medium toothbrush Paro M43 and standard toothpaste Elmex Caries Protection, (G3) standard medium toothbrush Paro M43 and anti-erosive toothpaste Elmex Protection Erosion, (G4) anti-erosive toothbrush Elmex Erosion Soft and standard toothpaste Elmex Caries Protection, (G5) anti-erosive toothbrush Elmex Erosion Soft and anti-erosive toothpaste Elmex Protection Erosion. Initially, surface baseline profiles were recorded using profilometry. In a total of 60 cycles, all specimens were exposed to hydrochloric acid (pH = 3) for 1 min, rinsed with tap water to stop the erosive attack and brushed according to the specific protocol of each group (15 brushing strokes per run). Enamel loss was determined by comparing the surface profiles before and after 60 cycles and the results were statistically analysed using analysis of variance (ANOVA).

RESULTS

The significantly highest loss of enamel was observed in the control group G1(1.4 ± 0.20 µm) (p < 0.001). G2 turned out to be the most abrasive toothbrush/-paste combination (1.12 ± 0.15 µm), G3 the least invasive (0.40 ± 0.04 µm) (p < 0.001, respectively).

CONCLUSION

All combinations of the investigated toothbrushes/-pastes reduce erosive/abrasive enamel wear. However, the highest reduction was observed for the combination of anti-erosive toothpaste and standard toothbrush (G3).

Prevention of Enamel Softening by Rinsing with a Calcium Solution before Dental Erosion

OBJECTIVES

This in situ study aimed to evaluate whether rinsing with a calcium-containing solution prior to an erosive attack reduces the softening of enamel.

MATERIALS AND METHODS

A total of 240 bovine enamel samples with determined baseline surface microhardness (KHN) were allocated to 5 runs in which each of the 12 volunteers performed the following experiment: 4 enamel samples were inserted in a custom-made intraoral appliance and carried in the mouth (upper jaw) for 30 min before each volunteer either rinsed his mouth for 60 s with a fluoride- and stannous ion-containing dental erosion protection mouth rinse as positive control (run 1), milk (run 2), a solution prepared from a 500-mg calcium effervescent tablet dissolved in 100 mL (run 3) or 200 mL (run 4) water, or did not perform any rinsing with a test solution before the erosive attack (run 5, negative control). To simulate the erosive attack, volunteers rinsed their mouth with a commercial soft drink (Sprite Zero) for 60 s and afterwards with water to stop the erosive process. Finally, surface microhardness was measured again and hardness loss (ΔKHN) calculated. A mixed effect model was fitted to the data set to investigate whether the different runs showed differences with respect to ΔKHN.

RESULTS

No significant difference in softening of enamel (mean of ΔKHN; lower confidence level/upper confidence level) was observed between the negative control run 5 (50.7; 60.8/40.6), run 2 (50.7; 60.8/40.6), run 3 (38.7; 48.8/28.6) and run 4 (40.7; 50.8/30.6) (p > 0.05, respectively). Enamel softening in the positive control run 1 (25.4; 35.6/15.3) was significantly lower compared to the softening in run 5 (p < 0.001). No significant difference was observed between run 1 and run 3 (p = 0.09).

CONCLUSION

Other than the fluoride- and stannous ion-containing dental erosion protection mouth rinse, none of the investigated calcium-containing solutions is able to significantly reduce erosion-induced softening of enamel.

Margin Integrity of Conservative Composite Restorations after Resin Infiltration of Demineralized Enamel

PURPOSE

To investigate the influence of pretreating demineralized enamel with a caries infiltrant on the margin integrity of Class V composite restorations bonded with different adhesives.

MATERIALS AND METHODS

A total of 60 specimens from bovine incisors were demineralized (21 days, acid buffer, pH 4.95) to create artificial enamel lesions, and circular Class V cavities were prepared. Cavities of half of the specimens were treated with either an unfilled etch-and-rinse adhesive (Syntac Classic; Ivoclar Vivadent), a filled etch-and-rinse adhesive (Optibond FL; Kerr), or a self-etch adhesive (iBond Self Etch; Heraeus Kulzer) (n = 10 per group). Demineralized enamel of the other half of the specimens was pretreated with a caries infiltrant (Icon; DMG) prior to adhesive application. All cavities were restored with a nanofilled composite material and thermocycled (5000×, 5°C-55°C). Margin integrity was evaluated using scanning electron microscopy, and the percentage of continuous margin was statistically analyzed (p < 0.05).

RESULTS

The significantly highest margin integrity was observed for Optibond FL, whether or not demineralized enamel was pretreated with the infiltrant. Pretreatment of demineralized enamel with the infiltrant resulted in a significant increase in margin integrity when the unfilled etch-and-rinse adhesive (Syntac Classic) or the self-etch adhesive (iBond Self Etch) was subsequently applied, but showed no significant improvement in combination with the filled etch-and-rinse adhesive (Optibond FL).

CONCLUSION

Application of a caries infiltrant can improve margin integrity of composite fillings in demineralized enamel when used in combination with the examined self-etch and unfilled adhesives.

Patient-reported symptoms during radiotherapy : Clinically relevant symptom burden in patients treated with palliative and curative intent

BACKGROUND

The benefits of patient-reported symptom assessment combined with integrated palliative care are well documented. This study assessed the symptom burden of palliative and curative-intent radiation oncology patients.

PATIENTS AND METHODS

Prior to first consultation and at the end of RT, all adult cancer patients planned to receive fractionated percutaneous radiotherapy (RT) were asked to answer the Edmonton Symptom Assessment Scale (ESAS; nine symptoms from 0 = no symptoms to 10 = worst possible symptoms). Mean values were used for curative vs. palliative and pre-post comparisons, and the clinical relevance was evaluated (symptom values ≥ 4).

RESULTS

Of 163 participating patients, 151 patients (90.9%) completed both surveys (116 curative and 35 palliative patients). Before beginning RT, 88.6% of palliative and 72.3% of curative patients showed at least one clinically relevant symptom. Curative patients most frequently named decreased general wellbeing (38.6%), followed by tiredness (35.0%), anxiety (32.4%), depression (30.0%), pain (26.3%), lack of appetite (23.5%), dyspnea (17.8%), drowsiness (8.0%) and nausea (6.1%). Palliative patients most frequently named decreased general wellbeing (62.8%), followed by pain (62.8%), tiredness (60.0%), lack of appetite (40.0%), anxiety (38.0%), depression (33.3%), dyspnea (28.5%), drowsiness (25.7%) and nausea (14.2%). At the end of RT, the proportion of curative and palliative patients with a clinically relevant symptom had increased significantly to 79.8 and 91.4%, respectively; whereas the proportion of patients reporting clinically relevant pain had decreased significantly (42.8 vs. 62.8%, respectively). Palliative patients had significantly increased tiredness. Curative patients reported significant increases in pain, tiredness, nausea, drowsiness, lack of appetite and restrictions in general wellbeing.

CONCLUSION

Assessment of patient-reported symptoms was successfully realized in radiation oncology routine. Overall, both groups showed a high symptom burden. The results prove the need of systematic symptom assessment and programs for early integrated supportive and palliative care in radiation oncology.

Magnetic field induced orbital polarization in cubic YbInNi4: determining the quartet ground state using x-ray linear dichroism

We have been able to induce a linear dichroic signal in the Yb M(5) x-ray absorption white line of cubic YbInNi(4) by the application of a magnetic field. The nonzero integrated intensity of the magnetic field induced dichroic spectrum indicates a net noncubic 4f orbital polarization. A quantitative analysis of the temperature and field strength dependence establishes that the crystal-field ground state is a Γ(8) quartet. The results demonstrate the potential of magnetic field induced linear dichroism as a new powerful approach for the investigation of the degeneracy and orbital degrees of freedom of cubic heavy-fermion and Kondo systems.

3-Alkyl- and 3-aryl-7H-furo[3,2-g]chromen-7-ones as blockers of the voltage-gated potassium channel Kv1.3

3-Alkyl- and 3-aryl-7H-furo[3,2-g]chromen-7-ones were synthesised and studied for their effects on voltage-gated K+ and Na+ channels of the neuroblastoma cell-line N1E-115 and K+ channels of L-929 mouse-fibroblasts, stably transfected with mKv1.3. All furocoumarins tested showed Kv channel blocking activities, the most potent one in a half-blocking concentration of 0.7 microM.

Psychodynamics and therapeutic aspects of anorexia nervosa. A study of family dynamics and prognosis

38 patients who had suffered from anorexia nervosa were examined and followed up in a catamnestic study, and their biography, family dynamics, eliciting situation and history of illness were studied. The investigation was carried out by means of interviews, questionnaires and personality tests. As to biography and family dynamics, our results are partly complementary and partly contradictory to previously published results of other investigations. Our patients received inpatient psychotherapy over an average period of 3 months and were followed up 2-5 years later. The following prognostic criteria proved to be significant: vomiting as part of the symptoms; chronification (psychotherapy delay), and ability to achieve a constructive therapist/patient alliance. Patients whose weight was largely back to normal by the end of therapy, but were still amenorrhoeic, showed unfavourable development in psychosocial relations. The catamnestic results improved with increasing time lapse between the end of therapy and follow-up investigation.