Evaluation of the breakage of orthograde endodontic ultrasonic tips.

Introduction: The objective of this study was to compare the breakage of 3 endodontic ultrasonic tips when removing dentin from extracted molars.

Methods: Three tips were tested (n = 10): BUC 1A (Obtura Spartan, Fenton, MO), CPR 5D (Obtura Spartan), and EDS 5E (Essential Dental Systems, South Hackensack, NJ). Extracted molars were prepared and mounted to a slow-speed alternating-current motor of a custom testing apparatus, which provided a 5-mm linear movement at an approximate rate of 4 mm/s.

Rational endodontics must pass the commonsense test.

By applying the principles of common sense, we can arrive at a rational approach to endodontics that eliminates concerns we have in using the rotary NiTi. We can use this same approach to improve our choices of what to use to create the original glide path. By switching from the poorly designed K-file to the more rationally designed and utilized relieved reamers, we not only create a more usable glide path, we quickly learn that an extension of this approach can eliminate the use of rotary NiTi and the various compromises it makes us incorporate in an attempt to use it safely.

A comparison of cyclic fatigue resistance in reciprocating and rotary nickel-titanium instruments.

The cyclic fatigue resistance of four nickel-titanium endodontic instruments was compared. K3, ProFile and GT Series X rotary instruments were examined along with SafeSiders reciprocating instruments. 30/0.

A review of failure modes in teeth restored with adhesively luted endodontic dowels.

Purpose: Previous clinical studies indicated loss of retention between dowel and tooth was a major cause of failure for passive endodontic dowels. Advances in luting cement technology may have improved the retention of dowels. The purpose of this systematic review was to determine the clinical failure modes for dowel/core/crown restorations luted using resin-based cements that are either self-etching or used in conjunction with a bonding agent.

Bacterial colonisation of root canal dentine previously treated with endodontic irrigants.

Certain irrigants leave antimicrobial residues on dentine. This study assessed if residues from MTAD, Endo-CHX, Peridex Oral Rinse or 6% NaOCl were inactivated by exposure to simulated leakage. Extracted teeth (15/group) were cut and drilled to produce a cylindrical canal space.

Cutting efficiency of 3 different instrument designs used in reciprocation.

Objective: This study examined the effect of flute number and cross-sectional area on the cutting efficiency of 3 reciprocating endodontic instruments twisted from rectangular stainless steel wire; 40/0.02 instruments at 25-mm length were compared.

Study Design: Seventy-five anterior teeth were prepared, divided into 3 groups, and operated on with a reciprocating handpiece at 2500 rpm for 5 seconds at around 500 grams of force: Group 1, SafeSiders; Group 2, Dentsply K-Files; Group 3, Dentsply K-Reamers.

Stability of doxycycline and chlorhexidine absorbed on root canal dentin.

Introduction: The antimicrobial agents chlorhexidine and doxycycline bind to dentin to provide sustained antimicrobial action. This study measured the stability of these chemicals on dentin adjacent to the root canal.

Methods: Extracted human teeth were instrumented and irrigated with either MTAD or Endo-CHX.

Interaction between chlorhexidine digluconate and EDTA.

The combination of chlorhexidine and EDTA produces a white precipitate. The aim of this study was to determine if the precipitate involves the chemical degradation of chlorhexidine. The precipitate was produced and redissolved in a known amount of dilute trifluoroacetic acid.

Radiopacity of endodontic materials on film and a digital sensor.

The purpose of this study was to compare the radiographic appearance of 12 endodontic materials as visualized on either Kodak Ultra-speed D speed film (Eastman Kodak Company, Rochester, NY) or a Gendex eHD digital sensor (Gendex Dental Systems, Milan, Italy). Ten discs of each material were radiographed alongside an aluminum alloy 1100 (Alcoa, Pittsburgh, PA) stepwedge that was used for reference. For every radiograph, the average grayscale value of the material was converted into absorbance notation and compared with that of the reference stepwedge in order to determine the equivalent radiopacity in terms of millimeters of Al 1100 per millimeter of material.

Measuring the radiopacity of luting cements, dowels, and core build-up materials with a digital radiography system using a CCD sensor.

Purpose: This study assessed the radiopacity of five luting cements, five dowels, and five core build-up materials using two target distances.

Materials And Methods: Materials were analyzed using a modified version of ISO protocol 4049. samples 1 mm thick were digitally radiographed alongside a stepwedge of aluminum alloy 1100 using a Trophy RVG-4 CCD sensor and 70 kVp X-ray generator.

Morphological measurements of anatomic landmarks in pulp chambers of human anterior teeth.

This in vitro study measured key morphological features of pulp chambers in anterior teeth and tested the hypothesis that the distance from the lingual surface (midpoint from the cusp tip to the lingual CEJ) to the pulp chamber (the midpoint from the buccal to the lingual CEJ) was similar for different tooth types. Extracted human teeth were sorted and 100 samples of each of the following tooth types were chosen: maxillary central incisor (UCI), lateral incisor (ULI), and canine (UC), as well as mandibular central incisor (LCI), lateral incisor (LLI), and canine (LC). All teeth were digitally radiographed on a 1-mm X-ray grid.

In vitro evaluation of five core materials.

Purpose: This in vitro study determined the fracture strength of five core materials supported by two different endodontic dowels. Diametral tensile strength and microhardness of the three resin composite core materials used in this study were also tested.

Material And Methods: The fracture strength study used one lanthanide-reinforced flowable resin composite (Ti-Core Auto E), one titanium- and lanthanide-reinforced composite (Ti-Core), one lanthanide-reinforced composite (Ti-Core Natural), and two metal-reinforced glass ionomer core materials (Ketac Silver and GC Miracle Mix).

Find canals faster through basic research.

Achieving access and finding canals are the key first steps in the endodontic procedure. This has always been a time-consuming, qualitative procedure that relies on the dentist's experience and feel. Recent basic research has been published that shows that the anatomic morphological measurements concerning the pulp chamber are very consistent in every tooth.

Comparison of the retention of 5 core materials supported by a dental post.

Purpose: This study evaluated the retention of dental post heads (No. 2 Flexi-Post) embedded in 5 core materials (1 automix resin composite, 2 hand-mixed resin composites, and 2 glass ionomers).

Materials And Methods: Samples were prepared by embedding post heads in 4.

Post design and its impact on the root and crown.

To optimize the longevity of an overlying restoration, it is important to follow proper engineering principles. These include the requirement of either an internal or external ferrule. When sufficient tooth structure does not exist to support an internal ferrule, it becomes necessary to use a porcelain-fused-to-metal restoration.