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Research paper thumbnail of Outcome of Different Processing Methods on Mechanical and Physicochemical Properties of Human Dentin as a Potential Natural Scaffold

Regenerative engineering and translational medicine, Nov 30, 2020

Dentin has been considered a promising scaffold for bone regeneration. This study investigated th... more Dentin has been considered a promising scaffold for bone regeneration. This study investigated the effects of two different demineralization and deproteinization methods on the mechanical and physicochemical properties of dentin as a potential scaffold for tissue engineering approaches. Eighty dentin discs were divided into five groups according to the treatment process: control (C), no treatment; DEM1, complete demineralization with HCl; DEM2, partial demineralization with different concentrations of EDTA; DEP1, complete deproteinization using NaOCl solution; and DEP2, partial deproteinization by boiling water. The treated dentin discs were characterized using ATR-FTIR and SEM. The compressive strength, elastic modulus, and microhardness values of all C and treated samples were measured. They were analyzed using one-way ANOVA, Kruskal-Wallis, and Weibull analysis. FTIR showed significantly reduced mineral/matrix ratio in demineralized groups (DEM1 and 2) (p < 0.001), while increase of mineral/matrix ratio in DEP1 was not significant (p = 0.31). SEM observations revealed open dentinal tubules in DEM1 group and lower amounts in the other groups. The C showed the highest compressive strength (78.18 ± 16.19 MPa), and the DEM1 showed the lowest (0.84 ± 0.32 MPa). The treated groups showed lower Weibull moduli (m), when compared with the C group. The DEP2 (642 ± 318.9) and DEM1 (2.9 ± 1.37) groups showed the highest and lowest modulus of elasticity, respectively. DEM1 showed the least hardness values (10.27 ± 3.09) compared to the other groups (p < 0.001). Based on the results, the DEM1 showed confirmed demineralization and lowest mechanical properties. The highest mechanical properties belonged to DEM2 and DEP2 groups which both were partially treated. Depending on the purpose of the regeneration, the dentin processing method can be selected. Whenever the high mechanical properties are more important in scaffold selection, DEM2 and DEP2 are the best choices. Lay Summary This study investigated the effects of two different demineralization and deproteinization methods including DEM1, demineralization with HCl; DEM2, demineralization with EDTA; DEP1, deproteinization using NaOCl solution; and DEP2, deproteinization by boiling water on the mechanical and physicochemical properties of dentin as a potential scaffold. Based on the results, the DEM1 showed confirmed demineralization and lowest mechanical properties. The highest mechanical properties belonged to DEM2 and DEP2 groups which both were partially treated. Depending on the purpose of the regeneration, the dentin processing method can be selected. Whenever the high mechanical properties are more important in scaffold selection, DEM2 and DEP2 are the best choices. Future studies should be conducted to assess the osteoinductive/osteoconductive potential Yasaman Erfan and Tahereh Sadat Jafarzadeh Kashi contributed equally to this work.

Research paper thumbnail of Outcome of Different Processing Methods on Mechanical and Physicochemical Properties of Human Dentin as a Potential Natural Scaffold

Regenerative Engineering and Translational Medicine, 2020

Dentin has been considered a promising scaffold for bone regeneration. This study investigated th... more Dentin has been considered a promising scaffold for bone regeneration. This study investigated the effects of two different demineralization and deproteinization methods on the mechanical and physicochemical properties of dentin as a potential scaffold for tissue engineering approaches. Eighty dentin discs were divided into five groups according to the treatment process: control (C), no treatment; DEM1, complete demineralization with HCl; DEM2, partial demineralization with different concentrations of EDTA; DEP1, complete deproteinization using NaOCl solution; and DEP2, partial deproteinization by boiling water. The treated dentin discs were characterized using ATR-FTIR and SEM. The compressive strength, elastic modulus, and microhardness values of all C and treated samples were measured. They were analyzed using one-way ANOVA, Kruskal-Wallis, and Weibull analysis. FTIR showed significantly reduced mineral/matrix ratio in demineralized groups (DEM1 and 2) ( p < 0.001), while inc...

Research paper thumbnail of Resistance to demineralisation of adjacent enamel and dentine, fluoride release and dentine bond strength of fluoride-containing self-etch adhesive systems

Journal of Clinical and Experimental Dentistry, 2020

Background: The current study aimed to assess the amount of fluoride released from fluoride-conta... more Background: The current study aimed to assess the amount of fluoride released from fluoride-containing dental adhesives and its effect on micro-tensile bond strength (µTBS) and on resistance to demineralisation of dentine and enamel. Material and Methods: Two fluoride-containing dental adhesives, and a fluoride-free adhesive were used as experimental adhesives. After thermal cycling the µ-TBS of adhesives to dentine and the failure mode were assessed. The fluoride release and cross-sectional microhardness (CSMH) of specimens were measured before and after one day, 7 and 28 days of pH-cycling. The data were analysed using one-way ANOVA, Weibull statistics and repeated measures ANOVA. Results: The results indicated a significant difference between the group of FL and both the SE and LBF groups (p≤0.001). The CSMH values of both the dentine and enamel underneath the adhesives was reduced at 28 th day of the pH-cycling compared to the baseline (p≤0.001). From day 1 to day 28, the released fluoride declined in both the fluoride containing dental adhesives (p≤0.001). Conclusions: Based on the results, the released fluoride from dental adhesives may adversely influence the bond strength and durability of the resin/dentine interface. Moreover, the released fluoride didn't improve the resistance to demineralisation of adjacent enamel and dentine to bond interface.

Research paper thumbnail of Fracture resistances of zirconia, cast Ni-Cr, and fiber-glass composite posts under all-ceramic crowns in endodontically treated premolars

The Journal of Advanced Prosthodontics

The aim of the present study was to evaluate the fracture resistances of zirconia, cast nickel-ch... more The aim of the present study was to evaluate the fracture resistances of zirconia, cast nickel-chromium alloy (Ni-Cr), and fiber-composite post systems under all-ceramic crowns in endodontically treated mandibular first premolars. MATERIALS AND METHODS. A total of 36 extracted human mandibular premolars were selected, subjected to standard endodontic treatment, and divided into three groups (n=12) as follows: cast Ni-Cr post-and-core, one-piece custom-milled zirconia post-and-core, and prefabricated fiberglass post with composite resin core. Each specimen had an all-ceramic crown with zirconia coping and was then loaded to failure using a universal testing machine at a cross-head speed of 0.5 mm/min, at an angle of 45 degrees to the long axis of the roots. Fracture resistance and modes of failure were analyzed. The significance of the results was assessed using analysis of variance (ANOVA) and Tukey honest significance difference (HSD) tests (α=.05). RESULTS. Fiberglass posts with composite cores showed the highest fracture resistance values (915.70±323 N), and the zirconia post system showed the lowest resistance (435.34±220 N). The corresponding mean value for the Ni-Cr casting post and cores was reported as 780.59±270 N. The differences among the groups were statistically significant (P<.05) for the zirconia group, as tested by ANOVA and Tukey HSD tests. CONCLUSION. The fracture resistance of zirconia post-and-core systems was found to be significantly lower than those of fiberglass and cast Ni-Cr post systems. Moreover, catastrophic and non-restorable fractures were more prevalent in teeth restored by zirconia posts.

Research paper thumbnail of Outcome of Different Processing Methods on Mechanical and Physicochemical Properties of Human Dentin as a Potential Natural Scaffold

Regenerative engineering and translational medicine, Nov 30, 2020

Dentin has been considered a promising scaffold for bone regeneration. This study investigated th... more Dentin has been considered a promising scaffold for bone regeneration. This study investigated the effects of two different demineralization and deproteinization methods on the mechanical and physicochemical properties of dentin as a potential scaffold for tissue engineering approaches. Eighty dentin discs were divided into five groups according to the treatment process: control (C), no treatment; DEM1, complete demineralization with HCl; DEM2, partial demineralization with different concentrations of EDTA; DEP1, complete deproteinization using NaOCl solution; and DEP2, partial deproteinization by boiling water. The treated dentin discs were characterized using ATR-FTIR and SEM. The compressive strength, elastic modulus, and microhardness values of all C and treated samples were measured. They were analyzed using one-way ANOVA, Kruskal-Wallis, and Weibull analysis. FTIR showed significantly reduced mineral/matrix ratio in demineralized groups (DEM1 and 2) (p < 0.001), while increase of mineral/matrix ratio in DEP1 was not significant (p = 0.31). SEM observations revealed open dentinal tubules in DEM1 group and lower amounts in the other groups. The C showed the highest compressive strength (78.18 ± 16.19 MPa), and the DEM1 showed the lowest (0.84 ± 0.32 MPa). The treated groups showed lower Weibull moduli (m), when compared with the C group. The DEP2 (642 ± 318.9) and DEM1 (2.9 ± 1.37) groups showed the highest and lowest modulus of elasticity, respectively. DEM1 showed the least hardness values (10.27 ± 3.09) compared to the other groups (p < 0.001). Based on the results, the DEM1 showed confirmed demineralization and lowest mechanical properties. The highest mechanical properties belonged to DEM2 and DEP2 groups which both were partially treated. Depending on the purpose of the regeneration, the dentin processing method can be selected. Whenever the high mechanical properties are more important in scaffold selection, DEM2 and DEP2 are the best choices. Lay Summary This study investigated the effects of two different demineralization and deproteinization methods including DEM1, demineralization with HCl; DEM2, demineralization with EDTA; DEP1, deproteinization using NaOCl solution; and DEP2, deproteinization by boiling water on the mechanical and physicochemical properties of dentin as a potential scaffold. Based on the results, the DEM1 showed confirmed demineralization and lowest mechanical properties. The highest mechanical properties belonged to DEM2 and DEP2 groups which both were partially treated. Depending on the purpose of the regeneration, the dentin processing method can be selected. Whenever the high mechanical properties are more important in scaffold selection, DEM2 and DEP2 are the best choices. Future studies should be conducted to assess the osteoinductive/osteoconductive potential Yasaman Erfan and Tahereh Sadat Jafarzadeh Kashi contributed equally to this work.

Research paper thumbnail of Outcome of Different Processing Methods on Mechanical and Physicochemical Properties of Human Dentin as a Potential Natural Scaffold

Regenerative Engineering and Translational Medicine, 2020

Dentin has been considered a promising scaffold for bone regeneration. This study investigated th... more Dentin has been considered a promising scaffold for bone regeneration. This study investigated the effects of two different demineralization and deproteinization methods on the mechanical and physicochemical properties of dentin as a potential scaffold for tissue engineering approaches. Eighty dentin discs were divided into five groups according to the treatment process: control (C), no treatment; DEM1, complete demineralization with HCl; DEM2, partial demineralization with different concentrations of EDTA; DEP1, complete deproteinization using NaOCl solution; and DEP2, partial deproteinization by boiling water. The treated dentin discs were characterized using ATR-FTIR and SEM. The compressive strength, elastic modulus, and microhardness values of all C and treated samples were measured. They were analyzed using one-way ANOVA, Kruskal-Wallis, and Weibull analysis. FTIR showed significantly reduced mineral/matrix ratio in demineralized groups (DEM1 and 2) ( p < 0.001), while inc...

Research paper thumbnail of Resistance to demineralisation of adjacent enamel and dentine, fluoride release and dentine bond strength of fluoride-containing self-etch adhesive systems

Journal of Clinical and Experimental Dentistry, 2020

Background: The current study aimed to assess the amount of fluoride released from fluoride-conta... more Background: The current study aimed to assess the amount of fluoride released from fluoride-containing dental adhesives and its effect on micro-tensile bond strength (µTBS) and on resistance to demineralisation of dentine and enamel. Material and Methods: Two fluoride-containing dental adhesives, and a fluoride-free adhesive were used as experimental adhesives. After thermal cycling the µ-TBS of adhesives to dentine and the failure mode were assessed. The fluoride release and cross-sectional microhardness (CSMH) of specimens were measured before and after one day, 7 and 28 days of pH-cycling. The data were analysed using one-way ANOVA, Weibull statistics and repeated measures ANOVA. Results: The results indicated a significant difference between the group of FL and both the SE and LBF groups (p≤0.001). The CSMH values of both the dentine and enamel underneath the adhesives was reduced at 28 th day of the pH-cycling compared to the baseline (p≤0.001). From day 1 to day 28, the released fluoride declined in both the fluoride containing dental adhesives (p≤0.001). Conclusions: Based on the results, the released fluoride from dental adhesives may adversely influence the bond strength and durability of the resin/dentine interface. Moreover, the released fluoride didn't improve the resistance to demineralisation of adjacent enamel and dentine to bond interface.

Research paper thumbnail of Fracture resistances of zirconia, cast Ni-Cr, and fiber-glass composite posts under all-ceramic crowns in endodontically treated premolars

The Journal of Advanced Prosthodontics

The aim of the present study was to evaluate the fracture resistances of zirconia, cast nickel-ch... more The aim of the present study was to evaluate the fracture resistances of zirconia, cast nickel-chromium alloy (Ni-Cr), and fiber-composite post systems under all-ceramic crowns in endodontically treated mandibular first premolars. MATERIALS AND METHODS. A total of 36 extracted human mandibular premolars were selected, subjected to standard endodontic treatment, and divided into three groups (n=12) as follows: cast Ni-Cr post-and-core, one-piece custom-milled zirconia post-and-core, and prefabricated fiberglass post with composite resin core. Each specimen had an all-ceramic crown with zirconia coping and was then loaded to failure using a universal testing machine at a cross-head speed of 0.5 mm/min, at an angle of 45 degrees to the long axis of the roots. Fracture resistance and modes of failure were analyzed. The significance of the results was assessed using analysis of variance (ANOVA) and Tukey honest significance difference (HSD) tests (α=.05). RESULTS. Fiberglass posts with composite cores showed the highest fracture resistance values (915.70±323 N), and the zirconia post system showed the lowest resistance (435.34±220 N). The corresponding mean value for the Ni-Cr casting post and cores was reported as 780.59±270 N. The differences among the groups were statistically significant (P<.05) for the zirconia group, as tested by ANOVA and Tukey HSD tests. CONCLUSION. The fracture resistance of zirconia post-and-core systems was found to be significantly lower than those of fiberglass and cast Ni-Cr post systems. Moreover, catastrophic and non-restorable fractures were more prevalent in teeth restored by zirconia posts.