Pediatric Rotary Files: Evolution to Revolution

The main goal of pulp therapy in primary dentition is to preserve the primary tooth thus protecting future normal occlusion. Routinely, pulp debridement and canal shaping are done by manual H-files, K-files, Broach, etc. Manual instrumentation may be time- consuming, thus impacting the behaviour of the child negatively. Thus arises the need for alternate instrumentation which will reduce the time required for treatment with better treatment outcomes. In 1988, Walia et al. introduced Nickel-Titanium (Ni-Ti), which revolutionized the discipline of Endodontics. These Ni-Ti files have advantage of shape memory and super elasticity thus improving the canal preparation and resulting in better shaped canals. In 2002, for first time Barr et al reported the use of rotary Ni-Ti files for the therapeutic purpose during Pulpectomy procedure in pediatric patient. He observed better acceptance by pediatric patient and good quality obturation. Till 2016, pulpectomy procedures were accomplished by the combination of hand files and adult rotary files. Adult rotary files are designed according to the morphology for permanent teeth and adult jaw size, thus the use of adult rotary files are in primary teeth may result in lateral perforation due to softer dentine of roots of primary teeth and may cause discomfort to the child thus making child unco-operative. But in 2016, Ganesh et al., pioneered the specialization of Paediatric Endodontics with his invention of specially designed rotary files. Their shape was specially designated for application in tortuous canals of primary teeth. Presently, a variety of pediatric rotary files like Kedo-STM (India), Pro AF Baby GoldTM (India),PrimePedoTM (India), DXL-ProPedoTM (India), NeolixTM (France),Denco® Kids files (China) and, Sani® Kid rotary files (China). This review is an album of these newer files and clinical and in-vitro research on them.

What’s new for the clinician? - Excerpts from and summaries of recently published papers

Endodontic files are used to remove intracanal pulpal tissues, microbial biofilm, and toxic by-products and to develop a continuously tapering canal while maintaining the canal geometry that ultimately allows for the delivery of irrigating solutions and intracanal medicaments as well as the three-dimensional filling of the root canal system. Historically, stainless steel hand files have been used to perform canal shaping. However, these files are stiff and associated with increased operator fatigue, and when used in the preparation of curved root canals, the restoring forces of the files tend to return the file back to its original shape, resulting in canal transportation.

EVALUATION OF ROOT CANAL OBTURATION RESULTS WITH THE CANAL SHAPING SYSTEM WAVE ONE AND GUTTA THERMAFIL

Objective: To evaluate the results of root canal obturation with Wave One (WO) canal shaping system and Gutta Thermafil obturation system. Design: Nonrandomized prospective experimental trial between December 2020 and March 2021. Setting: Central Military Hospital 108. Subject: 30 lower incisors extracted teeth without stem rupture, without root damage such as fracture, stray, fissure. Results: The number of slices with the biggest gaps accounting for 16.7%. The number of slices with the smallest gaps accounting for 10%. The number of slices with gaps over the total slices accounted for 14.4%. The void area in the apical slice was 1,413 ± 519.5 µm2 and the largest void area was 38,654.2 ± 3,939.8 µm2. Conclusion: Thermafil Gutta Percha has a good fit to the canal wall, which can seal the canal more easily and accurately.

Evaluation of Bacterial Reduction after Root Canal Shaping Using ProTaper Gold and WaveOne Gold Rotary Systems

Introduction The present study evaluated bacterial reduction promoted by the WaveOne system (Dentsply Maillefer, Ballaigues, Switzerland) and ProTaper Gold system (PTG; Dentsply Maillefer) in human extracted central incisors. Methods Sixty-two maxillary central incisors that were infected with Enterococcus faecalis (ATCC 51299) were sterilized with ethylene oxide for 21 days, and then root canal initial bacterial sample was collected with paper points and plated on M-Enterococcus agar. The specimens were randomly divided into two groups according to instrumentation: WaveOne Gold group (n = 30) and PTG group (n = 30). Each group was further subdivided into subgroup A (n = 15) where no activation of the irrigant was performed, and subgroup B (n = 15) where passive ultrasonic activation (PUI) was applied. The other two specimens without contamination were control asepsis. After instrumentation, samples were collected with the use of paper points. The bacterial reduction was calculated using colony-forming unit and quantitative real-time polymerase chain reaction. Data were collected and statistically analyzed. Results All techniques significantly reduced the number of bacteria in the root canal (p < 0.05), in which PTG showed superior bacterial reduction than WaveOne Gold (p > 0.05). The aseptic control group did not show any bacterial growth. PUI showed a significant bacterial reduction with the WaveOne Gold group. Conclusion It can be concluded that the single-file system, WaveOne Gold with the aid of passive ultrasonic irrigation, significantly reduce the bacterial number in the root canal similar to the multifile system, PTG.

Effect of Root Canal Transportation by Minimally Invasive Endodontic Access on Canal Orifice Dentin

Background: Minimally invasive endodontics (MI Endo) with minimal dentin shaping prevents root canal fracture in endodontically treated teeth. Alternatively, reduction of the surgical field and limitation of the visual field by MI Endo make root canal shaping difficult. The purpose of this study is to analyze the effect of minimally invasive (MI) shaping of canal orifice dentin by evaluating the shaping characteristics of TruNatomy (TN), a Ni–Ti file developed for MI Endo.Methods: A J-shaped canal model was used to compare the final canal morphology formed using a MI shaping TN or conventional shaping ProTaper NEXT (PTN) file. The TN files were used in two experimental groups: no straight-line access (A) and straight-line access (B). The PTN files of the control were similarly classified: no straight-line access (C) and straight-line access (D). The increase in canal width and the median displacement (transportation) among the groups were compared.Results: The analysis of the canal width prepared with the TN file showed that the displacement of the inner canal curve increased at the point 5 mm from the apex in Groups A and B; however, the displacement of the outer width increased at the other measurement sites. In Groups C and D using PTN, the displacement of the inner canal curve increased at points 3–5 mm from the apex. Alternatively, the displacement on the outer width increased at 8 mm, and the displacement in Group D increased significantly. The canal transportation in the case with a TN file was 0.1 mm or smaller for Groups A and B, although the PTN preparation showed significant transport 3–5 mm from the apex on the inner curve of Group D compared with Groups A and B.Conclusions: TN shaping preserves the tooth structure and canal geometry without straight-line access. The TN file developed based on the concept of MI Endo facilitates accurate root canal shaping and reduces transportation.

Experimental Study of the Effects of Torsional Loading on Three Types of Nickel-Titanium Endodontic Instruments

In modern endodontics, nickel-titanium (NiTi) rotary instruments are used on a large scale for root canal shaping. Nevertheless, the separation of an instrument is a serious concern during shaping. The aim of this study is to determine and compare the torsional fracture characteristics of three types of NiTi endodontic instruments, each with different cross-section designs and movements performed during root canal shaping: Endostar E3 (Endostar, Poldent Co. Ltd., Warsaw, Poland); Reciproc R25 (VDW, Munich, Germany); and Protaper Next X2 (Dentsply Maillefer, Ballaigues, Switzerland). Fifteen instruments are used in this study, divided in three groups (n = 5): Group Endostar, Group Reciproc and Group Protaper. For testing, each instrument is used to shape five simulated root canals, following which its torsional stress to failure is measured. The fracture lengths of all three groups are roughly between 2 and 3 mm from the tip. Higher values of the moment of torsion in fracture, and smaller values of the maximum twisting angle are observed for Group Endostar, as well as closer to circular cross-sections. However, the values of the shear tension are similar for all three groups, because the disadvantage given by the fracture section shape for Groups Reciproc and Protaper is compensated either by size or by intrinsic properties of the instrument material. For the shear tension the Endostar values are insignificantly increased (Kruskal–Wallis test, p = 0.207), and in the case of the maximum twist angle the Protaper values are insignificantly increased (Kruskal–Wallis test, p = 0.287). Because of the instruments shape and conicity, the analysis had to be carried out separately with regard to the length of the fractured tip. Rules-of-thumb are extracted from the study for current practice: if a blockage of the first 2 to 3 mm part of the tip can be anticipated (by the excessive curving of the instrument), the handpiece must be adjusted to torque values that do not exceed 1.5 to 2.5 N · cm for Endostar and 1 to 2 N · cm for Reciproc and Protaper instruments.

Evaluation of preparation times of WaveOne Gold reciprocating instruments compared to two analogous counterparts

Manufacturers are constantly developing new products to optimise endodontic treatment. These newer file systems are often associated with increasing expenditure of instrumentation and can affect the cost effectiveness of root canal treatment. Recently, companies have emerged that claim to have successfully reproduced many of the more established endodontic file systems manufactured by Dentsply Sirona (Ballaigues, Switzerland). EdgeEndo (Albuquerque, New Mexico, USA) and PacDent (Brea, CA, USA), which manufacture files similar in design to that of Dentsply Sirona, claim that they are similar and sell them at a lower price. A performance comparison of the replica file systems to their original is of clinical importance. The aim of this ex vivo study was to compare the total glide path and canal preparation times of WaveOne Gold Glider (Dentsply Sirona) combined with the Primary WaveOne Gold (Dentsply Sirona), Edge GlidePath (Edge Endo, Albuquerque, New Mexico, USA) followed by the Primary EdgeOne Fire (EdgeEndo); and One File G Glide Path (Pac-Dent, Brea, CA, USA) file combined with the Primary One File G (Pac-Dent) Shaping file. Sixty curved untreated canals of extracted, human, mandibular molars were randomly divided into three groups of 20 canals each for mechanical glide path enlargement and root canal shaping. Group 1 (WaveOne Gold Glider + Primary WaveOne Gold); Group 2 (Edge GlidePath + Primary EdgeOne Fire); and Group 3 (One File G Reciprocating Glide Path File + Primary One File G Reciprocating shaping file). The total time taken to prepare a glide path and to complete the root canal preparation of each canal was recorded (in seconds) by means of an iPhone stopwatch (Apple Inc., Cupertino, California). The time taken to change files was not recorded. Throughout the instrumentation process, RC Prep was used as a lubricant, and5 mL 3% sodium hypochlorite was used as irrigation solution. Mean and standard deviations were determined for each group, and analysis of variance was used to statistically compare the mean glide path preparation times for the three groups. The fastest final canal preparation time was achieved by WOGG/PWOG (41.78 ± 10.58 s), followed by OFGP/ POFS (42.02 ± 12.16 s) and then EGP/PEOF (42.49 ± 10.44 s). There were no statistically significant differences between the canal preparation times of the three combination groups (p>0.05).

Microbiological Aspects of Root Canal Infections and Disinfection Strategies: An Update Review on the Current Knowledge and Challenges

The oral cavity is the habitat of several hundreds of microbial taxa that have evolved to coexist in multispecies communities in this unique ecosystem. By contrast, the internal tissue of the tooth, i.e., the dental pulp, is a physiologically sterile connective tissue in which any microbial invasion is a pathological sign. It results in inflammation of the pulp tissue and eventually to pulp death and spread of inflammation/infection to the periradicular tissues. Over the past few decades, substantial emphasis has been placed on understanding the pathobiology of root canal infections, including the microbial composition, biofilm biology and host responses to infections. To develop clinically effective treatment regimens as well as preventive therapies, such extensive understanding is necessary. Rather surprisingly, despite the definitive realization that root canal infections are biofilm mediated, clinical strategies have been focused more on preparing canals to radiographically impeccable levels, while much is left desired on the debridement of these complex root canal systems. Hence, solely focusing on “canal shaping” largely misses the point of endodontic treatment as the current understanding of the microbial aetiopathogenesis of apical periodontitis calls for the emphasis to be placed on “canal cleaning” and chemo-mechanical disinfection. In this review, we dissect in great detail, the current knowledge on the root canal microbiome, both in terms of its composition and functional characteristics. We also describe the challenges in root canal disinfection and the novel strategies that attempt to address this challenge. Finally, we provide some critical pointers for areas of future research, which will serve as an important area for consideration in Frontiers in Oral Health.

On comprehensive analysis of root canal shaping ability of three endodontic files of different kinematics

Infection of the tooth’s root canal requires what is called root canal treatment (RTC). The most important part of endodontic treatment is to shape the root canal and remove its infected portion using endodontic files of various protocols, kinematics and designs that suit the particular geometry. Cleaning and Shaping the canal efficiently remove the root canal bacterial biofilms or tissue remnants while keeping its natural geometry. The result is determined by shaping the ability of the relevant endodontic file. In the available literature, no norm has been established for the measurement of various endodontic files’ ability to do effective shaping. We present in this study a method to analyse and measure the shaping ability of endodontic files of three different kinematics.

Lasers in Endodontic: A review

Since the development of ruby laser by Maiman in 1960 & application of laser for endodontics by Weichman in 1971, a variety of papers on potential applications for lasers in endodontics have been published. Lasers have been a significant advancement in the field of endodontics. Be it effective cleaning, root canal treatment, surgery etc. The lateral accessory canals and anatomical complexities have been a restraint in root canal procedure, for such cases lasers have been introduced to simplify the process & have good clinical results. As there has been a boon in the improvement of laser techniques, many latest lasers having a broad array of characteristics is accessible and can also be helpful in several areas related to dentistry. When compared with conventional techniques, laser treatments has been proven to be more advantageous. The purpose of this article is to summarize laser applications in endodontics, including their use in pulp diagnosis, dentinal hypersensitivity, pulp capping and pulpotomy, sterilization of root canals, root canal shaping & obturation & apicectomy. This article reviews the role of lasers in endodontics since the early 1970s & summarizes what future may hold for endodontics. With the potential availability of many new laser wavelengths and modes, much interest is developing in this promising field.