INTRODUCTIONCalcium Hydroxide was introduced in endodontics as a direct pulpcapping agent and is highly recommended and widely accepted as an inter-appointment intracanal endodontic dressing. It demonstrates a pronounced antibacterial activity against most of the bacterial species identified in endodontic infections. It can be mixed with a variety of vehicles such as distilled water, saline solution, propylene glycol and glycerine. Most of the substances used as vehicles do not have significant antimicrobial activity. However, due to the relative inefficiency of CH in the elimination of both facultative anaerobes and yeasts, it has been combined with other medicaments such as 2% CHX gel, Iodoform, Camphorated Paramonochlorophenol (CPMC), to obtain a wide spectrum antimicrobial action [1].The merits of CH have also been disputed, not only concerning its efficacy as an antimicrobial agent, but also because of possible apical leakage of the obturated canal system after its use [2]. Incomplete removal of CH medicaments from root canal surface, prevents the sealer from penetrating into the dentinal tubules, interferes with the normal setting reaction resulting in potential reduction of sealer adaptation, thus, affecting the seal of obturating material leading to microleakage and subsequent treatment failure [3]. Hence, while placing an intracanal medicament it is important to consider its effect on leakage of the root canal system [4].The purpose of this study was to evaluate the effect of three CH based intracanal medicaments on the apical sealing ability of AH Plus-guttapercha obturation. The medicaments used in the study were freshly prepared paste of CH mixed with normal saline, freshly prepared paste of CH mixed with 2% CHX solution and a commercially available paste of CH and iodoform in silicone oil-Vitapex. Hypothesis tested was that CH based intracanal medicaments would adversely affect the apical sealing ability of AH Plus guttapercha obturated root canals. MATERIALS AND METHODSThis in vitro study was carried out in the Department of Conservative Dentistry and Endodontics, Mahatma Gandhi Mission's Dental College and Hospital, Navi Mumbai, Maharashtra, India. Hundred permanent single rooted, non-carious human teeth with intact apices and curvature less than 10 degrees extracted for periodontal or orthodontic reasons were selected for the study. Teeth with immature root apices, cracks, root caries, curvatures, fracture and resorption defects were excluded. Samples were disinfected in 5% sodium hypochlorite (PDP, India) solution for one hour and stored in 0.9% normal saline (Althea Pharma Pvt. Ltd. India) in air tight containers until use. Specimen Preparation:To ensure that all specimens were the same length they were resected 15 mm from the apex using a diamond disc with water coolant. The length was standardized Keywords: AH Plus, Chlorhexidine, Saline, Vitapex ABSTRACT Introduction: Calcium Hydroxide (CH) is one of the most commonly used intracanal medicaments which can be used with various vehicles.

Clinicians are frequently challenged by endodontically treated teeth that have obstructions, such as hard impenetrable pastes, separated instruments, silver points or posts in their root canals. Intracanal separation of endodontic instruments may hinder cleaning and shaping procedures within the root canal system, with a potential impact on the outcome of treatment. Broken instruments usually prevent access to the apex and the prognosis of teeth with broken instruments in the canals may be lower than for normal ones. The prognosis of these cases mainly depends on the preoperative condition of the periapical tissues. For these reasons, an attempt to remove broken instruments should be undertaken in every case.Ultrasonics have often been advocated for the removal of broken instruments because the ultrasonic tips or endosonic files may be used deep in the root canal system. Furthermore, the use of an ultrasonic endodontic device is not restricted by the position of the fragment in the root canal or the tooth involved. This case report elaborates on retrieval of broken instrument lodged in the coronal third of the root canal using ultrasonics and dental operating microscope.