Biomaterial Database

[Electronic Apex Locator as a dental instrument]. 2009

S Lin, and O Winocur-Arias, and I Slutzky-Goldberg

Endodontics and Dental Trauma Unit, Dept. of Dental Medicine, Rambam Medical Center, Haifa, Israel.

Electronic Apex Locators (EAL) have become widely used in the last decade. The first apex locator was introduced in 1962, based on a constant electrical resistance (6.5 K.) between the oral mucosa and periodontal ligament. The first and second generations of EAL were inaccurate and could not detect the apex in the presence of conducting fluids. The third generation solved this problem by using two alternating frequencies and calculating the impedance between them. This provided reliable and accurate results in dry canals, or in the presence of blood, electrolytes or other fluid in the root canals, when the pulp was necrotic or when there was a perforation along the root. The Root ZX and Apit (Endex) are the most documented devices. The new fourth generation of apex locators is a diverse group: some use multifrequency currents, others use a "lookup matrix" rather than calculate the readings. Several of the newer EALs are smaller, and others connect to computers.

UI	MeSH Term	Description	Entries
D009061	Mouth Mucosa	Lining of the ORAL CAVITY, including mucosa on the GUMS; the PALATE; the LIP; the CHEEK; floor of the mouth; and other structures. The mucosa is generally a nonkeratinized stratified squamous EPITHELIUM covering muscle, bone, or glands but can show varying degree of keratinization at specific locations.	Buccal Mucosa,Oral Mucosa,Mucosa, Mouth,Mucosa, Oral
D010513	Periodontal Ligament	The fibrous CONNECTIVE TISSUE surrounding the TOOTH ROOT, separating it from and attaching it to the alveolar bone (ALVEOLAR PROCESS).	Alveolodental Ligament,Alveolodental Membrane,Gomphosis,Alveolodental Ligaments,Alveolodental Membranes,Gomphoses,Ligament, Alveolodental,Ligament, Periodontal,Membrane, Alveolodental,Periodontal Ligaments
D003762	Dental Instruments	Hand-held tools or implements especially used by dental professionals for the performance of clinical tasks.	Instrument, Dental,Dental Instrument,Instruments, Dental
D004581	Electronics	The study, control, and application of the conduction of ELECTRICITY through gases or vacuum, or through semiconducting or conducting materials. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Electronic
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D014076	Tooth Diseases	Diseases involving the TEETH.	Disease, Tooth,Diseases, Tooth,Tooth Disease
D014092	Tooth Root	The part of a tooth from the neck to the apex, embedded in the alveolar process and covered with cementum. A root may be single or divided into several branches, usually identified by their relative position, e.g., lingual root or buccal root. Single-rooted teeth include mandibular first and second premolars and the maxillary second premolar teeth. The maxillary first premolar has two roots in most cases. Maxillary molars have three roots. (Jablonski, Dictionary of Dentistry, 1992, p690)	Root, Tooth,Roots, Tooth,Tooth Roots
D018915	Root Canal Preparation	Various preparatory steps prior to ROOT CANAL THERAPY by extirpation of diseased pulp and preparation of access cavity to receive the sealing material.	Access Cavity Preparation,Endodontics Access Cavity Preparation,Access Cavity Preparations,Preparation, Access Cavity,Preparation, Root Canal,Root Canal Preparations