Effect of Propylene Glycol on the Sealing Ability of Mineral Trioxide Aggregate and Calcium-Enriched Mixture Cement Apical Barriers

Management of External Inflammatory Root Resorption following Tooth Autotransplantation Using a Modified Combination of Triple Antibiotics

External inflammatory root resorption (EIRR) is one of the most undesirable potential repercussions of various types of trauma and traumatic injuries to the tooth and its structure. This detrimental phenomenon may lead to severe complications, the consequent destruction of dental tissues, and eventual tooth loss. In the presented case, following the autogenous transplantation of tooth #17 as the host-tissue replacement for tooth #18, signs of EIRR were radiographically detected after 6 months. However, the thorough preparation of root canals, which involves complete cleaning and shaping, in addition to the application of a modified combination of triple antibiotics, consisting of penicillin G, metronidazole, and ciprofloxacin (PMC), managed to arrest EIRR. Moreover, the obturation of root canals using calcium-enriched mixture (CEM) cement as the endodontic biomaterial as well as the proper management of EIRR resulted in the healing of periradicular pathosis, abatement of clinical symptoms, and finally refunctionalisation of the tooth during a follow-up period of 2 years. It seems that the appropriate disinfection of the root canal system using PMC next to the prevention of microbial recontamination using CEM cement can perfectly manage EIRR.

Effect of Propylene Glycol on the Bond Strength of Two Endodontic Cements

Introduction

This study evaluated the effect of propylene glycol (PG) on the push-out bond strength of calcium-enriched mixture (CEM) cement compared to mineral trioxide aggregate (MTA).

Methods and Materials

The lumens of two hundred 2±0.2 mm-thick root sections from human extracted teeth were prepared to achieve a diameter of 1.3 mm. The samples were then allocated into eight groups of 25 on the basis of the materials used (MTA or CEM cement) and different proportions of PG (0%, 20%, 505, and 100%). In each group, 0.4 mL of the liquid was mixed with 1 g MTA or CEM cement. After incubation, the push-out strength of the samples was measured using a universal testing machine. Data were analyzed using the two-way ANOVA followed by one-way ANOVA and student's t-test.

Results

The MTA group showed significantly higher bond strength in comparison with CEM group (P≤0.001). Also 100% and 20% PG increased the bond strength of MTA (P≤0.001). For CEM cement, 100% and 50% PG decreased the bond strength (P≤0.001).

Conclusion

This in vitro study demonstrated that while PG increased the push-out bond strength of MTA, it is not recommended for mixing with CEM cement.

Setting Time and Surface Microhardness of Mineral Trioxide Aggregate and 1% and 5% Fluoride-Doped Mineral Trioxide Aggregate Mixed with Water and Gel-like Polymer

Introduction

Mineral trioxide aggregate (MTA) is extensively used in endodontics. However, it has limitations such as long setting time, low compressive strength and poor handling properties. Our study aimed to compare the setting time and surface microhardness of MTA and fluoride-doped MTA (FMTA) using gel-like polymer (GLP) or distilled water (DW) as liquid.

Methods and Materials

An MTA-like cement was prepared by mixing Portland cement, bismuth oxide and gypsum (75%, 20% and 5%, respectively). FMTA (1% and 5%) was made by substituting 1% and 5% of MTA powder with fluoride. GLP, composed of methyl cellulose (MC) and propylene glycol (PG), was used as the hydrating liquid and compared with distilled water. Six experimental groups (n=10) were examined for each test. The samples were subjected to Vickers surface microhardness test after 4 and 28 days. Setting time was measured using ANSI/ADA standards. Data was analyzed using two-way and repeated measured ANOVA and the Tukey HSD tests.

Results

The MTA-like cement hydrated with GLP showed a significantly reduced setting time (P<0.05); 1% FMTA, mixed with GLP, had the shortest initial and final setting times. The microhardness values of all samples increased at different rates during 28 days (P<0.00001). The microhardness significantly decreased by addition of fluoride to MTA (P<0.001).

Conclusions

The results of the present in vitro study suggested that using GLP as the hydrating liquid enhances the setting time with no adverse effect on the surface microhardness. However, adding fluoride can negatively affect the microhardness of MTA.