Biomedical subjects

T Attin

Publications and source records attributed to T Attin.

65 records · Page 4Linked to original sources

PubMedDate not supplied

Use of variable remineralization periods to improve the abrasion resistance of previously eroded enamel.

The objective of the study was to evaluate the period of remineralization needed to re-establish the resistance of eroded enamel against brushing abrasion. Enamel specimens were prepared from 84 polished bovine incisors. The samples were evenly distributed among 7 groups (A-G) and submitted to ten alternating de- and remineralization cycles which included abrasion by toothbrushing. Demineralization was accomplished by immersing the specimens in the erosive soft drink Sprite Light((R)) for 1 min. Remineralization was performed by storing the samples in artificial saliva for either 0 min (A), 10 min (B), 60 min (C) or 240 min (D). After each remineralization, the specimens were brushed in an automatic brushing machine. Group E (erosion and 240 min remineralization, but no brushing) group F (erosion, but no remineralization and no brushing), and group G (brushing, but no erosion and no remineralization) served as controls. After performing the cycles, loss of enamel was determined by profilometry. The following values (mean +/- SD) were obtained and statistically analyzed (p<0.05): group A (5.16+/-1.26 microm), B (2.47+/-0.68 microm), C (1.72+/-0.75 microm), D (1.11+/-0.42 microm), E (0.81+/-0. 23 microm), F (1.04+/-0.31 microm), G (0.22+/-0.15 microm). Only the differences between groups D, E, and F were statistically not significant. Under the chosen in vitro conditions, it is concluded that abrasion resistance of eroded enamel continuously increases with remineralization time. However, even after a period of 1 h of remineralization, abrasion of previously eroded enamel is increased

Analysis of Variance↗

PubMedDate not supplied

In situ evaluation of different remineralization periods to decrease brushing abrasion of demineralized enamel.

The aim of the present in situ study was to evaluate the effect of different periods of intraoral remineralization to decrease the susceptibility of previously demineralized enamel against toothbrushing abrasion. Six human enamel specimens (A-F) were recessed in the buccal aspects of each of eight intraoral appliances which were worn for 21 days by 8 panelists. Demineralization of the samples was performed twice a day extraorally in the acidic beverage Sprite Light for 90 s. Subsequently, the enamel specimens were brushed at different times. Specimen A was brushed immediately after the demineralization. The remaining samples B-E were brushed after the intraoral appliances had been worn for various periods of remineralization: specimen B, 10 min; C, 20 min; D, 30 min and E, 60 min, respectively. Specimen F was only demineralized and remineralized, but not brushed. After 21 days, enamel wear was measured with a laser profilometer. The following values (mean +/- standard deviation) were obtained: specimen A, 6.78+/-2.71 microm; B, 5.47+/-3.39 microm; C, 6.06+/-3.18 microm; D, 5.43+/-2.58 microm; E 4.78+/-2.57 microm, and F 0.66+/-1.11 micro;m. Analysis of variance revealed a significant influence of remineralization period on abrasive wear. However, even after a remineralization period of 60 min the wear was significantly increased as compared to the demineralized, but not brushed control. It is concluded that (1) abrasion resistance of softened enamel increases with remineralization period and (2) at least 60 min should elapse before toothbrushing after an erosive attack.

Amines↗

PubMedDate not supplied

Susceptibility of enamel surfaces to demineralization after application of fluoridated carbamide peroxide gels.

The aim of the present study was to evaluate the effect of experimental, fluoridated carbamide peroxide gels on formation of erosively induced demineralization of enamel. Seventy-five bovine enamel specimens were polished for microhardness determination and evenly distributed among 5 groups (A-E). The specimens were treated with 10% carbamide peroxide gel (8 h) and subjected twice to remineralization for 2 h in artificial saliva and demineralisation for 90 s in 1% citric acid, pH 2.2. The cycles of treatment with carbamide peroxide and twofold re- and demineralization were repeated three times. The carbamide peroxide gels were different in pH and fluoride content. Gel A (pH 7.0) and gel B (pH 5.7) were fluoridated (0.5% F), gel C (pH 7.0) and gel D (pH 5.7) were not fluoridated. In control group E the samples were not treated with a gel, but stored in 100% humidity for 8 h instead. Knoop microhardness of the specimens was assessed directly after polishing, and after each carbamide peroxide treatment and demineralization. All specimens showed a loss of microhardness at the end of the experiment. After 3 days, the controls revealed a significantly lower hardness loss compared to the specimens treated with the carbamide peroxide gels. Surface softening was significantly lower for the specimens of group A compared to the remaining groups (B-D), which were not significantly different among each other. It is concluded that treatment with either fluoridated or unfluoridated carbamide peroxide gels, at either neutral and acidic pH, renders enamel more susceptible to demineralization. Use of a fluoridated neutral gel decreases the degree of surface softening compared to the other gels investigated.

Analysis of Variance↗

PubMedDate not supplied

Influence of olive oil emulsions on dentin demineralization in vitro.

The effect of two different concentrations of olive oil emulsions on development of artificial caries-like dentin lesions under severe demineralizing conditions was investigated. Bovine dentin samples (n = 180) were ground flat, polished, divided into four groups, and subjected to three demineralization cycles per day. Samples were stored in one of the following solutions for 5 min prior to demineralization in a buffer solution (pH 5): Group 1: 50% oil emulsion (olive oil and distilled water); group 2: 5% oil emulsion; group 3: distilled water; and group 4: 1,500 ppm sodium fluoride. Daily up to 9 days, lesion depth (ld) and mineral loss (deltaZ) were determined by means of microradiography and analyzed by ANOVA and Tukey's studentized range test (p < or = 0.05). Lesion depth increased with time for all groups. Mineral loss increased in groups 1-3. A small but significant decrease in mineral loss was observed following treatment with lipid emulsions as compared to treatment with distilled water, but fluoride treatment was considerably more effective. Mean mineral loss (means +/- SD in vol% x microm) averaged over the study period was 4,368 +/- 1,599, 4,536 +/- 1,823, 4,849 +/- 1,798, and 789 +/- 177 for group 1, 2, 3, and 4, respectively. Ratio (deltaZ/ld) remained constant around 30 vol% for groups 1-3, but decreased for group 4. In conclusion, externally provided lipids have the potential to reduce dentin demineralization in vitro.

Analysis of Variance↗

PubMedDate not supplied

Brushing abrasion of softened and remineralised dentin: an in situ study.

The aim of the present in situ study was to evaluate the effect of different periods of intra-oral remineralisation on the susceptibility of softened dentin to toothbrushing abrasion. Groups of 6 human dentin specimens (A-F) were recessed in the buccal aspects of intra-oral appliances which were worn for 21 days by 11 volunteers. The samples were demineralised twice a day extra-orally in the acidic beverage Sprite Light (pH 2.9) for 90 s. Subsequently, the dentin specimens were brushed at different times. Specimen A was brushed immediately after demineralisation. Specimens B-E were brushed after the intra-oral appliances had been worn for various periods in the mouth: specimen B for 10 min, C for 20 min, D for 30 min and E for 60 min. Specimen F was not brushed (control). After 21 days, dentin wear was measured with a profilometer. The following values (means +/- standard deviation) were recorded (microm): A, 23.6 +/- 16.7; B, 37.9 +/- 29.7; C, 31.8 +/- 26.5; D, 18.5 +/- 10.5; E, 15.3 +/- 11.6; F, 12.6 +/- 6.7. There was a statistically significantly increased dentin loss for groups A, B and C as compared to the controls (U test: p < 0.05). However, after intra-oral periods of 30 and 60 min, wear was not significantly higher than in unbrushed controls. It is concluded that for protection of dentin surfaces at least 30 min should elapse before toothbrushing after an erosive attack.

Carbonated Beverages↗

PubMedDate not supplied

Method to detect minimal amounts of calcium dissolved in acidic solutions.

The study describes the application of the Arsenazo III method for detection of minimal amounts of calcium 12.4-49.4 micromol/l in different acidic solutions (hydrochloric acid, oxalic acid, maleic acid, phosphoric acid, tartaric acid, citric acid, lactic acid and acetic acid) adjusted to pH 2.0, 2.3 and 3.0. A mixture of the respective calcium concentrations with distilled water served as control. The experiments were run with ten repeats in series. Assessment of intra- and interassay coefficient of variation, and lower limit of quantification revealed that depending on the acid used, the Arsenazo III method is a reliable tool to quantify minimal calcium contents in acidic solutions.

Arsenazo III↗

PubMedDate not supplied

Class II restorations with a polyacid-modified composite resin in primary molars placed in a dental practice: results of a two-year clinical evaluation.

This study evaluated the two-year success rate of a hybrid composite material (TPH-Spectrum; Dentsply DeTrey, Konstanz, Germany) and a polyacid-modified composite resin (Compoglass, Vivadent, Schaan, Liechtenstein) in Class II restorations placed in primary molars in a dental practice. In each of 52 children, at least two primary molars were restored. Ninety-six primary molars were filled with TPH-Spectrum using the total-etching technique, and 94 with Compoglass without acid etching prior to application of the bonding adhesive. At baseline, one and two years, the restorations were assessed according to the Ryge criteria. Forty-seven children with a total of 132 fillings (68 TPH-Spectrum, 64 Compoglass) were evaluated after two years. The cumulative success rate after 24 months amounted to 89.2% for the Compoglass and 89.7% for the TPH-Spectrum restorations. No significant differences were observed between the two materials with respect to color matching, cavosurface discoloration, anatomic form, margin integrity and caries assessment. This investigation suggests that for a period of two years, the hybrid composite TPH-Spectrum and the polyacid-modified composite resin Compoglass, are suitable materials for restoration of primary molars.

Acid Etching, Dental↗

PubMedDate not supplied

Brushing abrasion of luting cements under neutral and acidic conditions.

Four resin based materials (Compolute Aplicap, ESPE; Variolink Ultra, Vivadent; C&B Metabond, Parkell and Panavia 21, Kuraray), two carboxylate cements (Poly-F Plus, Dentsply DeTrey and Durelon Maxicap, ESPE), two glass-ionomer cements (Fuji I, GC and Ketac-Cem Aplicap, ESPE), one resin-modified glass ionomer cement (Vitremer, 3M) one polyacid-modified resin composite (Dyract Cem, Dentsply DeTrey) and one zinc phosphate cement (Harvard, Richter & Hoffmann) were investigated according to their brushing resistance after storage in neutral and acidic buffer solutions. For this purpose 24 cylindrical acrylic molds were each filled with the materials. After hardening, the samples were stored for seven days in 100% relative humidity and at 37 degrees C. Subsequently, they were ground flat and polished. Then each specimen was covered with an adhesive tape leaving a 4 mm wide window on the cement surface. Twelve samples of each material were stored for 24 hours in a buffer solution with a pH of 6.8. The remaining 12 samples were placed in a buffer with a pH of 3.0. All specimens were then subjected to a three media brushing abrasion (2,000 strokes) in an automatic brushing machine. Storage and brushing were performed three times. After 6,000 brushing strokes per specimen, the tape was removed. Brushing abrasion was measured with a computerized laser profilometer and statistically analyzed with ANOVA and Tukey's Standardized Range Test (p < or = 0.05). The highest brushing abrasion was found for the two carboxylate cements. The lowest brushing abrasion was found for one resin based material, Compolute Aplicap. With the exception of three resin-based materials, a lower pH led to a higher brushing abrasion.

Analysis of Variance↗

PubMedDate not supplied

Influence of different bleaching systems on fracture toughness and hardness of enamel.

This study evaluated the influence of different bleaching procedures on the fracture toughness and microhardness of enamel. The labial aspects of 72 bovine incisors were prepared for microhardness determination. At baseline, Knoop hardness (KH) determination was conducted on each specimen. Moreover, the fracture toughness (FT) of enamel was assessed using Vickers hardness indentations with a load of 9.8 N. The length of both indentations and enamel cracks were recorded and used for calculation of FT. The samples were divided among six (A-F) groups (n = 12) and sectioned, resulting in a control and an experimental half. The samples were stored in artificial saliva for 10 days. The experimental halves were removed from the saliva and subjected to bleaching according to manufacturers' instructions (A: Opalescence Xtra, B: Opalescence Quick, C: Rapid White, D: Whitestrips, E: Opalescence 10%, F: Opalescence PF 15%). Bleaching with C-F was conducted daily (C: twice per day for 10 minutes, D: twice per day for 30 minutes, E: 8 hours, F: 4 hours), systems A-B were applied on the first and fifth day (A: twice for 10 minutes, B: 1 hour). Finally, Knoop hardness and FT were assessed and statistically compared to baseline values using Wilcoxon-tests (p < 0.05). KH and FT of the controls remained stable during storage in saliva. All bleaching regimens resulted in a statistically significant percentage loss of KH (mean + standard error of means): A: 17.3 +/- 2.8%, B: 8.6 +/- 3.3%; C: 83.5 +/- 0.61%, D: 29.0 +/- 1.9%, E: 9.0 +/- 2.91%, F: 5.4 +/- 2.2%. The percentage changes (mean + standard error of means) of FT in the experimental specimens were as follows: A: 3.9 +/- 9.5%, B: 0.1 +/- 4.7%; D: -8.2 +/- 7.1%, E: -18.9 +/- 4.7%, F: -12.0 +/- 4.7%. Due to severe surface softening, FT could not be determined for the samples in Group C. Applying Opalescence 10% resulted in a significant reduction in FT compared to baseline. In the remaining groups, changes in FT were not statistically significant.

Animals↗

PubMedDate not supplied

Fracture toughness of pin-retained class 4 restorations.

Standardized class 4 cavities were prepared in bovine incisors and restored with a microfilled composite resin. The composite restorations were retained either by acid etching technique (AET) alone or by acid etching technique in combination with a self-threading retentive pin. Pins covered with a bonding/opaquer coating (PCR pin) and uncovered pins (FO pin) were used. After having been aged for 3 days, the fracture resistance of the restorations was determined with a Universal Testing Machine. The restorations were loaded at an angle of 45 degrees. The restorations retained by AET and a PCR pin showed the highest failure load. The restorations accomplished with AET and a FO pin yielded the lowest fracture load. The fracture toughness of the restorations retained by AET and a PCR pin was slightly but statistically significant, higher compared to the restorations exclusively attached by acid etching technique. It was concluded that there was only a small increase of fracture toughness of large class 4 composite restorations if the acid etching technique was combined with the application of bonding/opaquer-covered retentive pins.

Acid Etching, Dental↗

PubMedDate not supplied

Diffusion behavior of eugenol from zinc oxide-eugenol mixtures through human and bovine dentin in vitro.

The objective of this in vitro study was to evaluate the long-term diffusion behavior of eugenol from different zinc oxide-eugenol mixtures through thin dentin layers. In 24 freshly extracted, caries-free human teeth standardized cavities were prepared exhibiting a dentin surface area of 7 mm2. The remaining thickness of the dentin close to the pulp chamber amounted to at least 0.2 mm. In a second experiment standardized dentin disks (0.2 mm thick) were prepared from 24 bovine incisors. The disks were embedded in epoxy resin, thus exposing a resin-free, standardized area of 7 mm2. Specimens from both experiments were inserted into a screw cap of a vial. Cp-Cap, Temp Bond, and two zinc oxide-eugenol mixtures (P/L ratios of 10:1 and 2:1) were applied to each of six specimens from both experiments. The opposing surface was in contact with 1 ml of Ringer solution. After 1 day, 7 days, and 21 days respectively, the amount of penetrated eugenol was determined with High-Performance Liquid Chromatography (HPLC). In both experiments we found a persistent release and diffusion of eugenol, irrespective of the applied material. However, for the second experiment, we saw more pronounced diffusion rates. Furthermore, the materials showed significant differences, particularly for low versus high P/L ratios.

Adolescent↗