Effect of Cavity Wall Thickness on Fracture Strength of Pulpotomized Primary Molar Teeth with Class II Amalgam Restoration

Mazhari, Fatemeh and Mehrabkhani, Maryam and Gharehchahi, Maryam (2007) Effect of Cavity Wall Thickness on Fracture Strength of Pulpotomized Primary Molar Teeth with Class II Amalgam Restoration. Journal of Mashhad Dental School, 31 (4). pp. 321-328.

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Introduction: Loss of tooth structure due to dental caries and cavity preparation can reduce fracture resistance, especially for endodontically treated teeth. The aim of this study was to assess the fracture resistance of pulpotomized primary molar teeth with class II amalgam restorations. Materials & Methods: In this invitro experimental study, 80 carious human extracted primary molar teeth (40 first molars and 40 second molars) were selected for pulpotomy preparation. The teeth were divided into four groups. Mesioor disto-occlusal (20 teeth) and Mesio-occluso-distal (20 teeth) cavities were prepared in both first and second primary molar teeth. Each group was divided into two subgroups with 10 teeth in each, according to thickness of the remaining walls (1.5 or 2.5mm). After restoring teeth with amalgam, all groups were stored in distilled water at 37°c for 7 days. They were then thermocycled for 1000 times 5°c to 55°c. Finally, the specimens were subjected to a compressive axial load in a universal testing machine (Zwick) at a crosshead speed of 0.5mm/min and fracture resistances of teeth were calculated in Newton. T-test was used for statistical analysis. Results: Mean fracture resistances of first and second molar teeth were 975±368.8 N and 1049±540.1 N respectively. In the first molar teeth, fracture resistance of two-surface cavities was significantly greater than three-surface ones (P<0.001), but the difference was not statistically significant in second molars. In the second molar teeth, the fracture strength of cavities with 2.5mm wall thickness was greater than 1.5mm thickness walls in both two (P=0.001) and three surface cavities (0.015) but in first molars, this difference was significant only in the three surface cavities (P=0.045). Conclusion: The fracture strength in pulpotomized primary molar teeth with amalgam restorations was high (more than maximum bite force in primary teeth) even in extensive 3-surface ones. Therefore, the teeth with large proximal carious lesions in school children can be restored with amalgam instead of Stainless steel (ss) crown. Key words: Cavity wall thickness, Fracture strength, Pulpotomized primary molar teeth, Amalgam restoration.

Item Type: Article
Subjects: WU Dentistry. Oral surgery
Divisions: Journals > Journal of Mashhad Dental School
Depositing User: jmds jmds
Date Deposited: 24 Sep 2017 13:52
Last Modified: 24 Sep 2017 13:52
URI: http://eprints.mums.ac.ir/id/eprint/3226

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