In vitro action of Bordeaux red wine on the microhardness of human dental enamel

Erosion behaviour of human, bovine and equine dental hard tissues

Dental hard tissues from different species are used in dental research, but little is known about their comparability. The aim of this study was to compare the erosive behaviour of dental hard tissues (enamel, dentin) obtained from human, bovine and equine teeth. In addition, the protective effect of the pellicle on each hard tissue under erosive conditions was determined. In situ pellicle formation was performed for 30 min on enamel and dentin samples from all species in four subjects. Calcium and phosphate release was assessed during 120 s of HCl incubation on both native and pellicle-covered enamel and dentin samples. SEM and TEM were used to examine surface changes in native enamel and dentin samples after acid incubation and the ultrastructure of the pellicle before and after erosive exposure. In general, bovine enamel and dentin showed the highest degree of erosion after acid exposure compared to human and equine samples. Erosion of human primary enamel tended to be higher than that of permanent teeth, whereas dentin showed the opposite behaviour. SEM showed that eroded equine dentin appeared more irregular than human or bovine dentin. TEM studies showed that primary enamel appeared to be most susceptible to erosion.

Morphometric, Densitometric, and Mechanical Properties of Maxillary Teeth in 5-Month-Old Polish Merino Sheep

This study was performed to determine morphological, densitometric, mechanical, and elemental characteristics of maxillary teeth in 5-month-old Polish Merino sheep. The total tooth volume (Tvol) was determined using quantitative computed tomography. Micro-computed tomography was used to determine the total enamel volume (Evol), volumetric enamel mineral density, total dentine volume (Dvol), volumetric dentine mineral density, and total tooth enamel and dentine volume (EDvol). Compression testing was used to determine the ultimate force of teeth. Microhardness of enamel and dentine was evaluated using Vicker's test. Elemental analysis of enamel and dentine was performed using a scanning electron microscopy technique. Tooth weight, length, Tvol, Evol, Dvol, and EDvol increased consequently from the lowest values for p2, then for p3 and p4, to the highest values obtained for M1 (all p < 0.05). Ultimate force reached the lowest value for p2 compared with the other teeth (p < 0.05). The comparison of left and right teeth did not reveal significant differences for all the evaluated parameters (p > 0.05). Volumetric mineral density, calcium and phosphorus content, and microhardness were higher in enamel than in dentine, while the opposite results were obtained for magnesium and oxygen (all p < 0.05). Significantly higher enamel microhardness was found in mandibular i1 compared with maxillary and mandibular premolars (p < 0.05). The elaborated experimental model of the determination of maxillary deciduous teeth traits may serve for further studies on the effects of physiological, pathological, environmental, nutritional, pharmacological, and toxicological factors affecting tooth development and mineralized tissue properties.

Surface roughness and erosion of nanohybrid and nanofilled resin composites after immersion in red and white wine

Aims:

This study aimed to investigate the effects of red and white wine on the surface roughness and erosion of nanohybrid and nanofilled resin composites.

Materials and Methods:

Sixty specimens of each resin-based composite (RBC) were prepared. Before immersion, baseline data roughness values were recorded using a profilometer. Three groups of discs (n = 20) were then alternately immersed in red wine, white wine, and deionized water (as a control) for 25 min and artificial saliva for 5 min over four cycles. The specimens were then stored in artificial saliva for 22 h. This process was repeated for 5 days following immersion in artificial saliva for 2 days. Subsequently, the process was repeated. After immersion, the specimens were evaluated and data were analyzed by two-way repeated analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) (α = 0.05).

Results:

Red wine caused significantly greater roughness and erosion than did white wine and deionized water (P < 0.05). Nanohybrid resin composites were significantly rougher than nanofilled resin composites (P < 0.05).

Conclusion:

The effects of red and white wine on the surface roughness and erosion of resin composite restorative materials depended upon the physical and chemical composition of the restorative materials and the types of wine.

The use of sub-ablative Er:YAG laser irradiation in prevention of dental caries during orthodontic treatment

PURPOSE

This « in-vitro » study had two specific aims: the first, to test using a universal testing machine whether sub-ablative Er:YAG laser irradiation prior to acid etching is effective in orthodontic bracket bonding and secondly using micro-hardness measurements and Scanning Electron Microscopy (SEM) observations to investigate the effectiveness of de-mineralization reduction in enamel treated with sub-ablative Er:YAG laser irradiation followed by fluoride varnish application.

MATERIALS AND METHODS

One hundred and eighty bovine permanent maxillary incisors were selected for shear bond strength testing and microhardness measurements. Sub-ablative Er:YAG laser irradiation was set at a power density of 2.5 J/cm(2), a frequency of 7 Hz and air/water spray. Brackets were bonded with an auto-curing resin paste. The shear bond strength was measured comparing laser irradiated and non-irradiated enamel surface, followed by SEM observation of the bracket-resin-enamel interface. Microhardness measurements were made on enamel samples before treatment, after samples preparation, and after demineralization.

RESULTS

While the adhesion of orthodontic brackets to bovine enamel after sub-ablative Er:YAG laser irradiation and acid etching is comparable to that obtained after conventional acid etching, the effect of laser irradiation associated with topical application of fluoride varnish increases the microhardness of enamel.

CONCLUSION

Sub-ablative Er:YAG laser irradiation before the acid etching doesn't reduce the shear bond whereas when associated with fluoride application it may play a role in caries prevention. Further studies will be necessary to establish the mechanism by which the protective laser activated fluoride effect is achieved.

Erosive effects of different acids on bovine enamel: release of calcium and phosphate in vitro

The present study intended to investigate minimal erosive effects of different acids on enamel during short time incubation via determination of calcium and phosphate dissolution. Bovine enamel specimens were eroded for 1-5 min with eight different acids of pH 2, 2.3 and 3 (citric (CA), maleic (MA), lactic (LA), tartaric (TA), phosphoric (PA), oxalic (OA), acetic (AA) and hydrochloric acid (HCl)). Calcium (Ca) and phosphate (P) release were determined photometrically using arsenazo III (calcium) and malachite green (phosphate) as substrates. Each subgroup contained eight enamel specimens. Amount of titratable acid was determined for all acidic solutions. MA, LA, TA, AA and HCl caused linear release of Ca and P, PA of Ca, CA of P. For CA, MA, LA, TA, AA, PA and HCl mineral loss was shown to be pH-dependent. Ca dissolution varied between 28.6+/-4.4 (LA, pH 2) and 2.4+/-0.7 nmol mm(-2)min(-1) (HCl, pH 3), P dissolution ranged between 17.2+/-2.6 (LA, pH 2) and 1.4+/-0.4 nmol mm(-2)min(-1) (HCl, pH 3). LA was one of the most erosive acids. AA was very erosive at pH 3. HCl and MA were shown to have the lowest erosive effects. There was only a weak correlation (r=0.28) between P and Ca release and the amount of titratable acid. The method of the present study allows investigation of minimal erosive effects via direct determination of P and Ca dissolution. During short time exposition at constant pH level, erosive effects mainly depend on pH and type of acid but not on amount of titratable acid.

The laboratory assessment of enamel erosion: a review

OBJECTIVES

To review the various methods and techniques available to assess enamel erosion in vitro.

DATA

Peer reviewed scientific articles.

SOURCES

Medline and Web of Science searches and manual searching.

STUDY SELECTION

Laboratory based assessments only included.

CONCLUSIONS

A number of macroscopic and microscopic techniques have been used to assess enamel erosion in vitro and in situ. This review examines techniques which are either well established or comparatively novel techniques that are being explored for their potential.