ABSTRACT
The circumferential 2 mm ferrule during the fabrication of the crown is strongly advocated for the long-term clinical success. During the routine clinical practice, the dentist encounters the endodontically treated tooth (ETT) with inadequacy of the ferrule in some segment due to caries, abrasion, and erosions. The aim of this in vitro study was to investigate the consequence of inadequate segmental ferrule location on fracture strength of the root canal-treated anterior and posterior teeth. Materials and Methods: Fifty each maxillary canine and mandibular premolar intact human teeth were root canal treated and sectioned at 2 mm above the cementum-enamel junction. The teeth samples were divided into 5 groups of 10 each. The G-I and G-V samples had the 360° ferrule and complete absence of the ferrule, respectively. The G-II had the inadequate ferrule on the palatal surface, while G-III and G-IV had inadequate ferrule at buccal and proximal area. Teeth samples were subsequently restored with glass-reinforced fiber post, composite core, and full veneer metal crown. The samples were tested with universal testing machine under static load to record the fracture resistance. The acquired data were subjected to ANOVA and Tukey's post hoc statistical analysis. Results: The G-I with circumferential ferrule showed the higher fracture resistance. The teeth samples with lack of the ferrule had the least fracture resistance. Among the segmental absence of ferrule, teeth samples with lack of the proximal ferrule were least affected. Deficiency of a ferrule on the lingual wall significantly affected the fracture strength in both anterior and posterior ETT. Conclusions: The ETT with sectional inadequacy of the ferrule is significantly more effective in resisting the fracture in comparison to the complete absence of the ferrule.
ABSTRACT
Objective: To estimate the effect of temperature over the physical properties of commonly used luting cements. Material and Methods: The two set of cylindrical shaped cement samples measuring 12mm X 6mm and 4mm X 8mm were fabricated from non-eugenol zinc oxide, glass ionomer, zinc phosphate, Zinc polycarboxylate, resin cements. These two sets of samples were utilized to test compressive and diametral tensile strength respectively. Forty cement samples from each mold were fabricated and distributed between 14, 22, 37 and 550C (N=10). The samples were tested under universal testing machine, and data subsequently analyzed using One-way ANOVA and Tukey multiple comparison's statistical methods at p > 0.05. Results: The higher temperature resulted in noticeable reduction in the compressive strength of non-eugenol -zinc oxide, Zinc-phosphate, Zinc poly carboxylate cements. The highest compressive strength was recorded for non-eugenol zinc oxide (8.08 Mpa) at 370C, Zinc phosphate (91.01Mpa) at 140C, and for zinc polycarboxylate (83.06 Mpa) at 370C. The comparative values for respective cements at 550C were 6.40Mpa, 59.80Mpa, and 52.88 Mpa. The higher temperature had insignificant effect on the compressive strength of glass ionomer cement, while composite resin cement indicated minor deterioration. Conclusion: The relative mouth temperature influences the physical properties of the luting cements.