Standardization of endodontic protocol in armed forces : A comparative CBCT guided invivo analysis of three contemporary endodontic systems ability in maintaining original internal root canal anatomy : A prospective multicentric randomized controlled trial

(a) Purpose of the study : To formulate a standardized, simplified and minimal inventory based root canal preparation protocol which aids in maintaining the internal root canal anatomy to give a predictable endodontic outcome.

(b) Objectives :

i. To compare the canal centering ability and maintaining of original internal root canal anatomy while canal preparation with Rotary, Reciprocating systems and Self adjusting File Systems.

ii. To compare and contrast instrumented areas of root canal wall by the various systems

iii. To compare the time efficiency of various contemporary endodontic systems.

Study Design

90 Patients age 18 years to 50 years reporting to dental centre requiring primary endodontic treatment in mandibular molars will be included in the study. Informed consent will be taken. The patients will be randomly assigned into three groups of 30 samples each. In Group A cases, root canal will be prepared by rotary system using Hyflex files, Group B by reciprocating system using Wave One files and Group C by a self-adjusting vibratory adaptive file system. Complete canal cleaning and shaping will be completed in one sitting.  Prior preparation, the tooth will be imaged by CBCT. Then the tooth in consideration will be prepared with the assigned instrument by following manufacturer instructions and adhering to conventional endodontic protocol of isolation, access preparation, cleaning and shaping. After preparation, the tooth is again imaged by CBCT, canals will be metrically assessed for changes in curvature and transportation during canal preparation, mean total widths and outer and inner width measurements will be determined on each central canal path and differences will be statistically analyzed. Areas of uninstrumented root canal wall will also be noted. Time taken for canal preparation will be noted.

The preparations will be analyzed according to Schilder’s mechanical objectives of canal preparation i.e original internal anatomy maintained, canal centering ability and canal has a continuous smooth curve from canal orifice to apical terminus.

•       Canal transportation (CT) is calculated by formula (CT) = (M1 - M2) - (D1 - D2)

•       Centralization ability ratio   = (M1 - M2)/ (D1 - D2)

•       Result = 1.0 micron m is perfect centralization

•        Result closer to zero indicates poor centralization

M1 is the measurement of the quantity of voxels from the external surface of the mesial portion of the root to the mesial wall of the non-instrumented canal M2 is the measurement of the quantity of voxels from the external root surface of the mesial portion of the root to the wall of the canal after instrumentation. D1 is the measurement of the quantity of voxels of the external surface of the distal portion of the root to the distal wall of the no instrumented canal. D2 is the measurement of the quantity of voxels from the external surface of the distal portion of the root to the distal surface of the canal after instrumentation.

The instrument separation will be evaluated once the above procedure is completed. The used file will be then used to prepare more samples till marked deformation of file is noted visually. The total number of samples which can be prepared without deformation or separation will be noted. Data will be collected and it will be compiled, comprehensively analyzed and statistical analysis will be done.

Resume of relevant literature on the subject, with special reference to the areas in which information is lacking:

Important principle of endodontics is to maintain the original canal anatomy while striving for a continuous tapering preparation [1]. It relates to the ability of the instrument to uniformly prepare all the surfaces of the canal, thus enabling the central axis of the prepared canal coincide with that of the original canal, especially relevant in the canals with curvatures [2,3]. Centering ability a desirable quality is influenced both by the design of the instrument (taper, flexibility, type of alloy) and the root canal anatomy is also an important desirable quality [4-8].

Rotary instrumentation systems have resulted in procedural errors leading to failures [1-3]. Thus, oscillatory or reciprocating system were explored. The shaping of simulated canals was more centered using a reciprocating motion when compared to continuous rotation, but was more time consuming and require a dedicated endomotor.

 The recent addition is Self-Adjusting File (SAF), a vertical vibratory adaptive system of compressible lattice made from hollow nickel titanium cylinder with inherent metal memory which expands in canal, adapting to the shape in three dimensions. SAF incorporates an irrigation source through its hollow lattice design, allowing simultaneous irrigation and disinfection of the canal [9].

 CBCT imaging owing to low radiation dose, fast scan and sub millimetric resolution is an effective tool to evaluate and measure dentin thickness, canal curvature, apical transportation, and canal centering, as it provides images in orthogonal planes as well as in oblique planes [10].

REFERENCES (maximum 8)

1.    Luis Cardoso Rasquin, Fabíola Bastos de Carvalho, Regina Karla de Pontes Lima. IN Vitro Evaluation Of Root Canal Preparation Using Oscillatory And Rotary Systems In Flattened Root  Canals. J Appl Oral Sci. 2007; 15(1) : 65-9.

2.    Mateus Silveira Martins, Vânia Regina Camargo , José Roberto,Volmir João, Fernando Branco. CT Evaluation of Apical Canal Transportation Associated with Stainless Steel Hand Files, Oscillatory Technique and ProTaper Rotary System. Braz Dent J 2011; 22(4): 288 -293.

3.    Renato de Toledo Leonardo. ENDO-EZE Tilos Anatomic Endodontic Technology. Oral Health Journal, 2010; 6:1-7.

4.    Mathieu Goldberg, Sandrine Dahan, and Pierre Machtou . Centering Ability and Influence of Experience When Using WaveOne Single-File Technique in Simulated Canals. International Journal of Dentistry,2012; Article ID 206321: 1-7

5.     Ruttermann S  et al. Preparation of the coronal and middle third of oval root canals with a rotary or an oscillating system. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007; 104:852-6.

6.    Sung-Yeop You, Cheol, Kim. Shaping Ability of Reciprocating Motion in Curved Root Canals: A Comparative Study with Micro–Computed Tomography. J Endod 2011:1–5.

7.    Anisha Merh et al. To Comparatively Evaluate the Canal Centering Ability of the ENDO EZE AET System and Wave One System in Simulated Canals National Journal of Medical and Dental Research, Jan-March 2014; 2(2):32-41.

8.    Zohreh Khalik et al.canal centering ability of three rotary file systems in simulated canals.A comparative  study. Indian Dent Res 2009; 20 (4)

9.    Cohen S et al. The SAF Endo System: adaptive 3 D Cleaning and Shaping and

Disinfection. Endodontic Practice 2011; 4(7).