Assessing apical transportation in curved canals: comparison between cross-sections and micro-computed tomography

Abstract

Assessing apical transportation in curved canals: comparison between cross-sections and micro-computed tomography Abstract: The aim of this study was to compare two methods of assessing apical transportation in curved canals after rotary instrumentation, namely, cross-sections and micro-computed tomography (µCT). Thirty mandibular molars were divided into two groups and prepared according to the requirements of each method. In G1 (cross-sections), teeth were embedded in resin blocks and sectioned at 2.0, 3.5, and 5.0 mm from the anatomic apex. Pre-and postoperative sections were photographed and analyzed. In G2 (µCT), teeth were embedded in a rubber-base impression material and scanned before and after instrumentation. Mesiobuccal canals were instrumented with the Twisted File (TF) system (SybronEndo, Orange, USA), and mesiolingual canals, with the EndoSequence (ES) system (Brasseler, Savannah, USA). Images were reconstructed, and sections corresponding to distances 2.0, 3.5, and 5.0 mm from the anatomic apex were selected for comparison. Data were analyzed using Mann-Whitney's test at a 5% significance level. The TF and ES instruments produced little deviation from the root canal center, with no statistical difference between them (P > 0.05). The canal transportation results were significantly lower (0.056 mm) in G2 than in G1 (0.089 mm) (p = 0.0012). The µCT method was superior to the cross-section method, especially in view of its ability to preserve specimens and provide results that are more closely related to clinical situations.

Retracted: Micro‐computed tomography evaluation of apical transportation and centring ability of Reciproc and WaveOne systems in severely curved root canals

“…Apical transportation is a change in the original trajectory of the root canal in its apical portion (Freire et al 2012); and mainly occurs due to progressive removal of dentine along the outer wall root canals with large curvatures (Aguiar et al 2013). Instruments of reciprocating system are made with a metallic alloy, M-Wire, which promotes greater flexibility and resistance to cyclic fatigue when compared with conventional NiTi alloys (Kim et al 2012).…”

Quantitative transportation assessment in curved canals prepared with an off-centered rectangular design system

“…Although the two-dimensional approach represents a clear limitation of the method, it is important to point out that current three-dimensional-based techniques used to evaluate root canal transportation have not yet provided fully quantitative volumetric data, 5,13,14,15,16,17 resulting in the evaluation of limited selected slices and manual selection of gravity center points.…”

Periapical injection of betamethasone to control postoperative pain in emergency endodontic care - a randomized double blind clinical trial

“…On the other hand, they do not exert any effect on the COX-1 expression, which may explain their noninterference in certain biological processes 21 . Prolonged administration of corticosteroids, such as during the postoperative period may result in suppression of the hypothalamic-pituitary-adrenal axis (HHA), leading to bone mineral loss, causing osteoporosis and may increase the risk of cataracts, glaucoma, cutaneous effects And vascular changes 22,23 , effects on the central nervous system, changes in body fat distribution, increased susceptibility to infection, increased appetite and emotional disturbances [24][25][26] . The dose of betamethasone used in this study (0.05 mg / kg) is 40 times smaller than that of 2 mg / kg of dexamethasone (which is equipotent to betamethasone), employed by Czerwinsnky et al (1972) 27 which, according to these authors, did not produce significant adverse side effects.…”