Root-end surgery is necessary when primary endodontic treatment fails and the tooth cannot be managed successfully by conventional retreatment strategies. Over the last two decades, root-end surgical techniques have changed considerably due to the introduction of microscopes, ultrasonic instruments and dedicated root-end filling materials. This clinical perspective focuses on the development and use of hydraulic calcium silicate materials for root-end surgery. Keywords: clinical protocols, hydraulic calcium silicate cements, material properties, root-end surgery

Purpose: The aim of this study was to assess the antimicrobial activity of chemical disinfectants on alginate and silicone impression materials. The effect of chemical disinfectants on the dimensional stability of the impression materials was also assessed. Materials and Methods: For the microbiologic assessment, impressions of the maxillary arch were taken from 14 participants, 7 using alginate and 7 using an addition silicone. The impressions were divided into three sections. Each section was subjected to spraying with MD 520 or Minuten or no disinfection (control), respectively. Antimicrobial action of the chemical disinfectants was assessed by measuring microbial counts in trypticase soy agar (TSA) media and expressing the results in colony-forming units/cm2. The surface area of the dental impressions was calculated by scanning a stone cast using computer-aided design/computer-assisted manufacture and analyzing the data using a custom computer program. The dimensional stability of the impression materials after immersion in disinfectants was assessed by measuring the linear displacement of horizontally restrained materials using a traveling microscope. The percent change in length over 3 hours was thus determined. Results: Alginate exhibited a higher microbial count than silicone. MD 520 eliminated all microbes as opposed to Minuten. The bacterial growth after Minuten disinfection was almost twice as much for alginate than for addition silicone impressions. The chemical disinfectants affected the alginate dimensional stability. Minuten reduced the shrinkage sustained by alginate during the first hour of storage. Conclusions: Alginate harbors three times more microorganisms than silicone impression material. Chemical disinfection by glutaraldehyde-based disinfectant was effective in eliminating all microbial forms for both alginate and silicone without modifying the dimensional stability. Alcohol-based disinfectants, however, reduced the alginate shrinkage during the first 90 minutes of setting. The current studies also propose another method to report the surface area based on accurate estimation by 3D image analysis.

Aim: To evaluate potential tooth colour alteration effect of five root canal sealers using a bovine tooth model and the interaction of formaldehyde with bismuth compounds. Materials and methods: A preliminary test was performed to assess the interaction of bismuth oxide in contact with formaldehyde. Seventy bovine teeth were sectioned into blocks and cavities were created. Each cavity was filled with either: AH Plus, Acroseal, MTA Fillapex, Sealer 26, Endofill and then sealed with composite. Triple antibiotic paste and unfilled samples were used as the positive and negative controls, respectively. All the specimens were immersed in water. The colour was assessed with a spectrophotometer at different intervals: immediately after filling, 24 h, 15 days and 30 days after filling. The colour change and the luminosity were calculated. The statistical analysis was performed using non-parametric Kruskal-Wallis and Dunn test (P 0.05). Results: The bismuth oxide in contact with formaldehyde exhibited a black colour. All the sealers caused tooth colour alteration after the evaluated periods, with grey staining and low luminosity values observed with Sealer 26 samples. Conclusions: All the evaluated sealers caused tooth colour alteration. The tooth staining was visually detected for Sealer 26 and might be associated with the formaldehyde released and its interaction with the radiopacifier bismuth oxide. Keywords: discolouration, formaldehyde, root canal sealers, spectrophotometer, tooth staining

Purpose: Titanium dental implants have a high success rate; however, there are instances when a modified surface may be desirable. The aim of this article was to systematically review the different types of implant coatings that have been studied clinically, in vivo and in vitro, and the coating techniques being implemented. Materials and Methods: The literature was searched electronically and manually through The Cochrane Library, Medline, and PubMed databases to identify articles studying dental implant surfaces and coating techniques. The database search strategy revealed 320 articles, of which 52 articles were considered eligible-40 in relation to implant coatings and 12 to the coating technique. An additional 30 articles were retrieved by hand search. Results: Several materials were identified as possible candidates for dental implant coatings; these include carbon, bisphosphonates, bone stimulating factors, bioactive glass and bioactive ceramics, fluoride, hydroxyapatite (HA) and calcium phosphate, and titanium/titanium nitride. HA coatings still remain the most biocompatible coatings even though the more innovative bioglass suggests promising results. The most common coating techniques are plasma spraying and hydrocoating. More recent techniques such as the nanoscale technology are also discussed. Conclusions: Several implant coatings have been proposed, and some appear to give better clinical results and improved properties than others. Clinical trials are still required to provide compelling evidence-based results for their longterm successful outcomes.