The Root Apex locator aids our endodontist in defining the length of the teeth. It is a fully automatic root canal length measuring device (apex locator) which provides extremely accurate measurements in all canal conditions.

Advanced microprocessor ensures precise readings even in the presence of sodium hypochlorite, hydrogen peroxide, saliva, blood or pulp. The microprocessor also calibrates automatically, making it ready to use immediately after turning on the main switch. These features and more make it one of the most highly rated root canal length measuring devices on the market.

The NSK Endo-Mate DT is a device used to drill and measures the rotation speed as well as torque levles during root canal treatments. An autoreverse function activates when the present torque level has been exceeded. Endo-Mate's torque control system combined with the Apex Locator allows dentists and dental specialists to perform safe and more accurate root canal preparation.

The new ProTaper NiTi rotary files represent a revolutionary progression in root canal preparation procedures.3 The ProTaper files were specifically designed to provide superior flexibility, unmatched efficiency and greater safety.

The unique design features of the ProTaper files enables clinicians to more consistently create uniformly tapered shapes in anatomically difficult or significantly curved canals (Figures 1, 2). The set contains just six (6) simple-to-use files and the series is comprised of three "shaping" and three "finishing" instrument currently ava i la b le 21 mm and 25 mm lengths (Figure 3). The following information describes the ProTaper geometries.

The auxiliary shaping file, or Shaper X, is easy to recognize as there is no identification ring on its gold-colored handle. Shaper X, also referred to as Sx, has an overall length of 19 mm, providing excellent access in restrictive areas. The Sx file has a Do diameter of 0.19 mm, a modified guiding tip, and a 014 diameter approaching 1.20 mm. Shaper X has a much faster rate of taper from Do to D9 as compared to the other two shaping files. For example, at Ds, D7, Ds and 09 the instruments cross-sectional diameters are approximately equivalent to 0.50, 0.70, 0.90 and 1.10 mm, respectively (Figure 4). This file is used to optimally shape canals in shorter roots, relocate canals away from external root concavities, and to produce more shape, as desired, in the corona! aspects of canals in longer roots.

The ability of Shaper X to brush and cut dentin on the outstroke is an advantage over all other rotary NiTi instruments. In summary, after establishing a smooth, reproducible glide path over any portion of the length of the canal, Shaper X may be used, at anytime, to expand the preparation and may be thought of as an ideal substitute for gates glidden drills. Shaping File No. 1 and Shaping File No. 2, termed St and Si. are easy to recognize as they have purple and white identification rings on their handles, respectively.

The Si and Sz files have Do diameters of 0.17 mm and 0.20 mm, respectively, modified guiding tips, and their 014 maximal flute diameters approach 1.20 mm (Figure 5). The shaping files have increasingly larger tapers over the length of their cutting blades allowing each instrument to engage, cut and prepare a specific area of the canal. Shaping File No. 1 is designed to prepare the corona! one-third of a canal, whereas Shaping File No. 2 enlarges and prepares the middle one-third. Although both instruments optimally prepare the coronal two-thirds of a canal, they do progressively enlarge the apical one-third.

ProTaper files have a continuously changing helical angle and pitch over their 14 mm of cutting blades (Figure 9). Balancing the pitch and helical angles of an instrument optimizes its cutting action, effectively allows its blades to auger debris out of the canal, and importantly prevents the instruments from inadvertently screwing into the canal.

Another specific feature of the ProTaper files is each instrument has a modified guiding tip. This design feature allows each instrument to better follow the canal and enhances its ability to find its way through soft tissue and loose debris without damaging the root canal walls.

Another specific feature of the ProTaper files is each instrument has a modified guiding tip. This design feature allows each instrument to better follow the canal and enhances its ability to find its way through soft tissue and loose debris without damaging the root canal walls.

ProTaper files have short, 12.5 mm handles as compared to the more standard file handle length of 15 mm. This feature serves to improve access into the posterior regions of the mouth, especially when there is a narrow interocdusal space.

The ProTaper system features just six NiTi files which is the fewest number of instruments as compared to all other brand lines or series of files. In fact, in anatomically difficult or significantly curved canals, generally only three instruments are required to produce a fully tapered canal that exhibits uniform shape over length (Figure 12). Canals that have foramens larger than 0.30 mm are generally easy to prepare and may be accomplished utilizing a variety of different, currently available instruments.

When the "guidelines for use' are followed, the ProTaper NiTi rotary instruments will provide high performance and excellent safety. It is essential to prepare the access cavity so that there is a straightline pathway to the orifice(s). The pulp chamber should be filled brimful with either sodium hypochlorite (NaOCI) or a viscous chelator. Rotary instruments should only be placed in portions of the canal that have a confirmed, smooth and reproducible glide path. To fulfill this objective, small, flexible stainless steel 0.02 tapered hand files are used to create or confirm the glide path.

Additionally, small, flexible hand files provide information regarding straightline access, cross-sectional diameter and root canal system anatomy. Further, rotary NiTi instruments should only be used in the apical one-third of a canal that is patent and has a known, accurate working length. Finally, when incorporating the ProTaper instruments, clinicians should follow the specific method of use, observe the recommended sequencing of files, and adhere to the correct range of speed and prescribed torque suggested for each file.

The following summarizes the ProTaper rotary shaping file guidelines:

The access preporation is an essential element for successful endodontics.4 Preparing the endodontic access cavity is a critical step in a series of procedures that potentially leads style MA photograph atil5.!shcmowas to the three-dimensional obturation and the orifices just within this octane of the root canal system.

Access form. cavities should be cut so the pulpal roof, including all overlying dentin, is removed. The size of the access cavity is dictated by the position of the orifice(s). The axial walls are extended laterally such that the orifice(s) is just within this outline form. The internal walls are flared and smoothed to provide easy, straightline access into the orifice and the root canal system (Figure 13). Additionally, access preparations are expanded to eliminate any coronal interference during subsequent instrumentation. Access objectives are confirmed when all the orifices can be visualized

16 mm of cutting flutes and their Dis diameters are 0.42 and 0.47 mm, respectively. These small instruments provide an opening for the implementation of rotary instruments.

Scouter files immediately reveal the cross-sectional diameter of a canal and provide information as to whether the canal is open, restricted, or significantly calcified. Before any rotary instrument can be safely introduced into the canal, sufficient space must exist to accommodate and guide their tips. In other words, there must be a pilot hole of circumferential dentin and a smooth glide path for NiTi rotary instruments to follow. As an example, if a canal has been scouted to within 2-3 mm of anticipated working length with 10 and 15 hand files, then more space exists than the files' numerical names suggest. Recall the 10 and 15 hand files taper 0.02 mm/mm, have dilaceration. Further, before introducing rotary instruments, clinicians need to know if a single canal coronally subsequently divides or if two or more systems within a root merge along their length. It must be recognized that certain root canals exhibit anatomical configurations which preclude the safe use of NiTi rotary files.

Scouter files confirm the presence or absence of straightline access. Clinicians can observe the handle position of the smaller sized instruments to see if they are upright and paralleling the long axis of the tooth or skewed off-axis. In the instance where the roots are under the circumferential dimensions of the clinical crown and the file handle is upright, or 'ON' the long axis of the tooth, then the clinician is able to confirm both corona! and radicular straightline access. In instances where the handle of the initial scouting instrument is 'OFF' the long axis of the tooth, then pre-enlargement procedures should be directed towards uprighting the file handle (Figure 14).10•11 To upright the handle of the small scouter files oftentimes requires refining and expanding the access preparation and selectively removing the triangle of dentin from the corona! one-third of the canal.

This procedural distinction is critical and simplifies all subsequent instrumentation procedures while virtually eliminating many cleaning and shaping frustrations. Traditionally, a series of gates glidden drills, used like "brushes", were needed to upright the file so it would parallel the long-axis of the tooth. With just a single instrument, the ProTaper Sx file may be used to rapidly, effectively and safely remove the triangle of dentin (Figure 15). Once this restrictive dentin has been eliminated, the handles of the scouter files will be uprighted and 'stand-up' straight and tall. This important procedural step serves to relocate the coronal aspect of the canal towards the greatest bulk of dentin, simplifies the use of any subsequently placed instrument, and promotes safety.

Scouter files can provide information regarding root canal system anatomy. Clinicians need to appreciate the five commonly encountered anatomical forms which include canals that merge, curve, recurve, dilacerate or divide. Scouter files provide information regarding the anatomy and give important feedback regarding the canal's degree of curvature, recurvature, or if there is a

Scouter files can provide information regarding root canal system anatomy. Clinicians need to appreciate the five commonly encountered anatomical forms which include canals that merge, curve, recurve, dilacerate or divide. Scouter files provide information regarding the anatomy and give important feedback regarding the canal's degree of curvature, recurvature, or if there is a dilaceration. Further, before introducing rotary instruments, clinicians need to know if a single canal coronally subsequently divides or if two or more systems within a root merge along their length. It must be recognized that certain root canals exhibit anatomical configurations which preclude the safe use of NiTi rotary files.

The breakthrough to apical one-third finishing procedures is canal patency" and is performed by gently directing small, highly flexible files to the radiographic terminus (RT).5 To ensure patency, the file tip is intentionally inserted minutely through the foramen to discourage the accumulation of debris.

Importantly, working a small, flexible file to the RT will encourage the elimination of dental pulp, related irritants, and dentinal mud. Keeping the canal terminus patent discourages blocks, ledges and perforations.'2 It is illogical to assume that passing a small file passively and minutely through the apical foramen is going to prejudice the result or predispose to any irreversible conditions when one reflects on the rich collateral circulation and healing capacity available in the attachment apparatus.

Researchers, academicians and clinicians are well aware that when a file is passed through the entire length of a canal and its most apical extent is observed to be at the radiographic terminus, then, in actuality, the instrument is minutely long. Traditional wisdom advocates that since the apical extent of a canal terminates at the cementodentinal junction (Cal) then working length should extend to this anatomical landmark.'3 Although the Cal exists in a non-pulpally involved tooth, its position can never be precisely located clinically as this histological landmark varies significantly from tooth to tooth, from root to root, and from wall to wall within each canal. Working arbitrarily short of the radiographic terminus based on statistical averages encourages the accumulation and retention of debris, which may result in apical blocks that predispose to ledges and perforations.

Working short has led to many frustrations, interappointment flare-ups, 'unexplained- failures, surgical procedures and extractions.12 Electronic apex locators represent an improvement over radiographs for more accurately identifying the position of the foramen.'" Technological advancements in specific apex locators provide greater accuracy in length determination even in canals that contain exudates or electrolytes. It should be understood that apex locators do not replace films but are used intelligently and in conjunction with radiographs. When a predictable and smooth glide path is established to the RT and working length is confirmed, then the apical one-third of the canal can be 'finished' in a variety of ways.1°