Effect Of Simultaneous Working Length Control Postoperative Pain
Effect Of Simultaneous Working Length Control Postoperative Pain
The aim of this study was to evaluate the effect of simultaneous length control during root
 canal preparation on postoperative pain compared with separate working length determination
 and root canal preparation using electronic apex locator. During preparation of root canals,
 loss of working length (WL) can lead to instrumentation beyond the predefined apical limit of
 the preparation. This effect is mainly attributed to straightening of the root canal during
 instrumentation. Some studies showed, that this kind of over instrumentation as well as under
 instrumentation can adversely affect the outcome of the endodontic treatment, while it
 remains uncertain what exactly is the most favorable extent of the apical limit of root canal
 preparation. Furthermore, all endodontic instruments produce apical extrusion of debris, even
 when the preparation is kept within the confines of the root canal. Consequently,
 preparations ending in the periapical tissue will produce a greater amount of debris
 extrusion that could elicit a neurogenic inflammatory response resulting from an irritation
 of the periodontal ligament with subsequent postoperative symptomatic apical periodontitis.
 Therefore, it seems favorable to control the determined WL during root canal preparation to
 avoid preparations ending in the periapical tissue.
During preparation of root canals, loss of working length (WL) can lead to instrumentation
 beyond the predefined apical limit of the preparation. This effect is mainly attributed to
 straightening of the root canal during instrumentation. Some studies showed, that this kind
 of over instrumentation as well as under instrumentation can adversely affect the outcome of
 the endodontic treatment. Furthermore, all endodontic instruments produce apical extrusion of
 debris, even when the preparation is kept within the confines of the root canal.
 Consequently, preparations ending in the periapical tissue will produce a greater amount of
 debris extrusion that could result from an irritation of the periodontal ligament with
 subsequent postoperative symptomatic apical periodontitis. Therefore, it seems favorable to
 control the determined WL during root canal preparation to avoid preparations ending in the
 periapical tissue.

 Endodontic motors with integrated apex locators offer a solution to the described problem as
 they have been developed with the intention of making root canal treatment easier and faster.
 Besides torque and speed control, these devices also aim to continuously monitor and control
 the apical limit all the way through the mechanical preparation of the root canals and have
 an auto apical reverse (AAR) function that stops and reverse the rotation when the file tip
 reaches the predetermined apical limit of the preparation.

 E-CONNECT S (Eighteeth medical technology Co., Ltd, china) is an endomotor with integrated
 apex locator newly introduced in the market with continuous WL measuring function. It
 contains an optional module for rotary instrumentation, allowing the device to function as a
 low-speed hand piece, apex locator, or a combination of both. This motor has an
 attention-grabbing property that when an instrument reaches the predetermined working length,
 the motor automatically stops the instrumentation. Thus, it can be concluded that
 automatically stopping instrumentation when the instrument reaches the working length would
 decrease postoperative pain compared with manually controlling the working length by using
 stoppers during instrumentation (separate length determination and root canal preparation).

 The Root ZX (J Morita, Tokyo, Japan) is a third generation EAL where no calibration is
 necessitated, and a microprocessor analyzes the impedance quotient. It uses multiple
 frequencies to calculate the distance from the end of the canal. To measure location within
 the canal, third generation units (including Root ZX EAL) still use impedance measurements
 but have stronger microprocessors and can process the mathematical quotient and algorithm
 calculations required to obtain accurate readings. The change in electrical capacitance at
 the apical constriction is the basis for the operation of the Root ZX and its reported
 accuracy, even in presence of different electrolytes in the canal and under different
 clinical conditions; that's why it is considered the most commonly used apex locator.
Inclusion Criteria:

 -  Age between (20-50) years old with symptomatic irreversible pulpitis in permanent
 mandibular premolar teeth.

 -  Systemically- healthy patients (ASA I or II).

 -  Patients who agree to attend for recall appointments and provide written consent.

 Exclusion Criteria:

 -  Pregnant women and patients with pacemakers.

 -  Patients with bruxism or clenching or have taken analgesics during past 24 hours.

 -  Moderate or severe marginal periodontitis (i.e. pocket probing >3 mm).

 -  Necrotic pulp, pulp polyp, tooth tender to percussion, preoperative palpation pain,
 clinical progression into periapical abscess, fistula.

 -  Teeth with internal or external resorption, curvatures, open apices, root canal
 obliteration, perforation, incomplete root formation, teeth previously undergone root
 canal treatment, absence of opposing tooth to the related tooth or radiographically
 invisible canals.