Restor Dent Endod.  2015 May;40(2):104-112. 10.5395/rde.2015.40.2.104.

Effect of intracanal medicaments used in endodontic regeneration procedures on microhardness and chemical structure of dentin

• Yassen GH
• Eckert GJ
• Platt JA

• KMID: 2148859
• DOI: http://doi.org/10.5395/rde.2015.40.2.104

Abstract

OBJECTIVES
This study was performed to investigate the effects of different intracanal medicaments on chemical structure and microhardness of dentin.
MATERIALS AND METHODS
Fifty human dentin discs were obtained from intact third molars and randomly assigned into two control groups and three treatment groups. The first control group received no treatment. The second control group (no medicament group) was irrigated with sodium hypochlorite (NaOCl), stored in humid environment for four weeks and then irrigated with ethylenediaminetetraacetic acid (EDTA). The three treatment groups were irrigated with NaOCl, treated for four weeks with either 1 g/mL triple antibiotic paste (TAP), 1 mg/mL methylcellulose-based triple antibiotic paste (DTAP), or calcium hydroxide [Ca(OH)2] and finally irrigated with EDTA. After treatment, one half of each dentin disc was subjected to Vickers microhardness (n = 10 per group) and the other half was used to evaluate the chemical structure (phosphate/amide I ratio) of treated dentin utilizing attenuated total reflection Fourier transform infrared spectroscopy (n = 5 per group). One-way ANOVA followed by Fisher's least significant difference were used for statistical analyses.
RESULTS
Dentin discs treated with different intracanal medicaments and those treated with NaOCl + EDTA showed significant reduction in microhardness (p < 0.0001) and phosphate/amide I ratio (p < 0.05) compared to no treatment control dentin. Furthermore, dentin discs treated with TAP had significantly lower microhardness (p < 0.0001) and phosphate/amide I ratio (p < 0.0001) compared to all other groups.
CONCLUSIONS
The use of DTAP or Ca(OH)2 medicaments during endodontic regeneration may cause significantly less microhardness reduction and superficial demineralization of dentin compared to the use of TAP.

Keyword

Calcium hydroxide; EDTA; Endodontic regeneration; FTIR; Microhardness; Triple antibiotic paste

MeSH Terms

Calcium Hydroxide
Dentin*
Edetic Acid
Humans
Molar, Third
Regeneration*
Sodium Hypochlorite
Spectroscopy, Fourier Transform Infrared
Calcium Hydroxide
Edetic Acid
Sodium Hypochlorite

Figure

• 

  Figure 1 Schematic illustration of the experimental groups used in the study and the type of medicaments and/or irrigations used in each group. NaOCl, sodium hypochlorite; TAP, triple antibiotic paste; DTAP, methylcellulose-based triple antibiotic paste; Ca(OH)2, calcium hydroxide; EDTA, ethylenediaminetetraacetic acid.

• 

  Figure 2 Illustration of the method used to obtain dentin discs and the approach used to perform both microhardness and FTIR measurement on the same sample. (a) Dentin discs were cross-sectioned from caries free third molars; (b) The deep pulpal side of each dentin disc was subsequently ground and polished; (c) Half side of each treated dentin surface was used for microhardness measurement and the other half was used for FTIR measurement. FTIR, Fourier transform infrared spectrophotometer.

• 

  Figure 3 Bar graphs showing the Vickers microhardness of dentin treated with various intracanal medicaments and that of the control group. Different upper-case letters indicate significant differences (p < 0.05). TAP, triple antibiotic paste; DTAP, methylcellulose-based triple antibiotic paste; NaOCl, sodium hypochlorite; EDTA, ethylenediaminetetraacetic acid.

• 

  Figure 4 Bar graphs showing the phosphate/Amide I ratios of dentin treated with various intracanal medicaments and that of the control group. Different upper-case letter indicates significant differences (p < 0.05).TAP, triple antibiotic paste; DTAP, methylcellulose-based triple antibiotic paste; NaOCl, sodium hypochlorite; EDTA, ethylenediaminetetraacetic acid.

• 

  Figure 5 Representative attenuated total reflectance (ATR) spectra of each group. NaOCl, sodium hypochlorite; EDTA, ethylenediaminetetraacetic acid; Ca(OH)2, calcium hydroxide; DTAP, methylcellulose-based triple antibiotic paste; TAP, triple antibiotic paste.

• 

  Figure 6 Scatter correlation plots of phosphate/amide I ratios and microhardness measurements of various treatment groups and control group. The overall correlation analysis was high (r = 0.94, p < 0.0001). NaOCl, sodium hypochlorite; EDTA, ethylenediaminetetraacetic acid; DTAP, methylcellulose-based triple antibiotic paste; TAP, triple antibiotic paste.

• 

  Figure 7 Representative scanning electron microscope (SEM) images from dentin treated with various intracanal medicaments and from an untreated control dentin. (a) Untreated control dentin; (b) Dentin treated with NaOCl + EDTA; (c) Dentin treated with Ca(OH)2; (d) Dentin treated with DTAP; (e) Dentin treated with TAP.

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