The Effect of a Resin-based Sealer Cement on Micropunch Shear Strength of Dentin

doi:10.1016/j.joen.2008.07.003

Journal of Endodontics

Volume 34, Issue 10, October 2008, Pages 1215-1218

https://doi.org/10.1016/j.joen.2008.07.003 Get rights and content

Abstract

Dentinal tubules occupy a substantial proportion of total dentin volume, especially of inner dentin. Resin-based sealer cements are known to penetrate deeply into dentinal tubules, but their ability to influence root strength is controversial. In this study, the contribution of dentinal tubules to shear strength and the influence of a resin-based sealer on shear strength were evaluated. Coronal 100-μm sections of 12 single-canal premolar teeth were tested in different locations (buccal and proximal) and tubule directions (parallel and perpendicular) using the micropunch shear test (MPSS). Tests were also conducted by using 10 two-canal premolars, with one untreated canal and the other obturated using epoxy resin-based sealer (plus gutta-percha). No difference in MPSS was found because of location or tubule orientation (p > 0.05). Outer dentin had a higher MPSS than middle and inner dentin (p < 0.001). Tubule infiltration by epoxy resin did not increase MPSS.

Section snippets

Materials and Methods

This study was conducted using maxillary and mandibular premolars with either a single root (12 teeth) or two roots (10 teeth), extracted for orthodontic reasons. Teeth were stored in 1% chloramine T (Sigma-Aldrich, St Louis, MO) at 4°C until use. The protocol was approved by the Human Research Ethics Committee, University of Melbourne, Australia. Teeth were thoroughly cleaned, and the crown of each tooth was resected 2 mm apical to the cementoenamel junction. All samples were then prepared

Results

The mean MPSS of coronal root dentin in two locations (buccal and proximal), in two orientations (parallel and perpendicular), and in three areas tested (inner, middle, and outer) are shown in Table 1. The mean value of MPSS varied from 73.6 ± 18.3 to 117.5 ± 18.8 MPa. There were no statistically significant differences in MPSS between the two locations (buccal and proximal) (p = 0.28) or when comparing the two orientations with respect to dentinal tubules (p = 0.6). However, the mean MPSS of

Discussion

Using the punch shear test to show dentin strength was first reported by Roydhouse in 1970 (24). The shear strength of dentin varied from 68.6 MPa to 147 MPa depending on the site within the tooth, tooth type, and the direction of the punch in relation to the long axis of the tooth. Smith and Cooper (7) used a micropunch 100, 200, or 300 μm in diameter and reported that the value near the DEJ was higher than near the pulp. Dentin from root-filled teeth has been variously reported to be slightly

Conclusions

Using MPSS, no difference in punch shear strength of dentin was observed because of location (buccal or proximal) or to tubule orientation (perpendicular or parallel). Only the area tested (inner, middle, or outer) was found to show a difference. Epoxy resin infiltration of tubules did not increase shear strength of dentin.

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Effect of dentinal tubules and resin-based endodontic sealers on fracture properties of root dentin
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To investigate the role of dentinal tubules in the fracture properties of human root dentin and whether resin-filled dentinal tubules can enhance fracture resistance.
Crack propagation in human root dentin was investigated in 200 μm thick longitudinal samples and examined by light and scanning electron microscopy. 30 maxillary premolar teeth were prepared for work of fracture (Wf) test at different tubule orientations, one perpendicular and two parallel to dentinal tubules. Another 40 single canal premolars were randomly divided into four groups of 10 each: intact dentin, prepared but unobturated canal, canal obturated with epoxy rein (AH Plus™/gutta percha), or with UDMA resin sealer (Resilon^®/RealSeal^®). The samples were prepared for Wf test parallel to dentinal tubules. Wf was compared under ANOVA with statistical significance set at p < 0.05.
Dentinal tubules influenced the path of cracks through dentin, with micro-cracks initiated in peritubular dentin of individual tubules ahead of the main crack tip. A significant difference (p < 0.001) was found between Wf perpendicular to tubule direction (254.9 J/m²) vs. parallel to tubule direction from inner to outer dentin (479.4 J/m²). Neither canal preparation nor obturation using epoxy- or UDMA-based resins as sealer cements substantially influenced fracture properties of root dentin, despite extensive infiltration of dentinal tubules by both sealer cements.
Epoxy resin-based root canal sealer penetration into dentin tubules does not improve root filling dislodgement resistance
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Bond strength to radicular dentin and sealing ability of AH Plus in combination with a bonding agent
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Lack of correlation between sealer penetration into dentinal tubules and sealability in nonbonded root fillings
2012, International Endodontic Journal

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Basic research—technologyThe Effect of a Resin-based Sealer Cement on Micropunch Shear Strength of Dentin

Abstract

Section snippets

Materials and Methods

Results

Discussion

Conclusions

Arch Oral Biol

J Prosthet Dent

J Endod

Dent Mater

J Am Dent Assoc

Oral Surg Oral Med Oral Pathol Oral Radiol Endod

J Endod

J Endod

J Endod

J Endod

J Endod

J Endod

J Biomech

J Dent

J Dent

Arch Oral Biol

Basic research—technology
The Effect of a Resin-based Sealer Cement on Micropunch Shear Strength of Dentin