The Influence of Root Canal Preparation with ProTaper Next, WaveOne Gold, and Twisted Files on Dentine Crack Formation

(1) Background: Root canal preparation constitutes an important factor for success in endodontics. However, various complications may occur during this stage. The aim of this study was to compare the incidence of cracks within radicular dentin after instrumentation with ProTaper Next (PTN), WaveOne Gold (WOG), and Twisted Files (TF), which utilize different kinematics. (2) Methods: Eighty single-rooted teeth were classified into four groups (n = 20). Three groups were instrumented using PTN (X1, X2), WOG (Primary), and TF (SM1–3). The non-instrumented group constituted the control group. Post-preparation, the roots were sectioned 3, 6, and 9 mm from the apex using a low-speed saw (Southbay Technology Inc., San Clemente, CA, USA). The specimens were viewed through a microscope at x25 magnification (Leica M320, Wetzlar, Germany), and their surface was assessed tactilely to determine the presence of the crack. (3) Results: Partial cracks within radicular dentine were observed in all study groups (PTN: n = 4/20%, WOG: n = 3/15%, TF: n = 4/20%); no cracks were observed in the control group. No significant differences were observed among experimental groups. OR values for the incidence of cracks were: OR = 11.182 for PTN, OR = 8.2 for WOG, and OR = 8.2 for TF. (4) Conclusions: Instrumentation with PTN, WOG, and TF may result in dentinal cracks formation.

Disinfection of the root canal system: what should the protocol be?

The presence of micro-organisms within the root canal system is the critical aetiological factor in peri-radicular periodontitis. During root canal treatment (RCT) it is imperative that this infection and other organic debris are removed from the root canal system. This is challenging because complex tooth anatomy, the presence of a biofilm and the smear layer complicate the process. There are a number of irrigant chemicals and adjunctive systems available in contemporary endodontic practice that are used to disinfect the root canal system during root canal preparation. This article reviews the available evidence concerning these disinfection methods and concludes by presenting a clinical protocol supported by the literature. CPD/Clinical Relevance: A clinical protocol, supported by the literature, is presented for effective decontamination of the root canal system during root canal therapy.

Effect of rotary systems and root canal preparation and dentin crack formation

Evidence indicates that root canal preparation is a critical step upon which the prognosis of the endodontic treatment depends. Vertical root fractures can furtherly develop as propagations from the previously formed dentin cracks. Therefore, root canal preparation should be carefully approached with the minimal crack formation and careful dentin removal. Different modalities have been proposed in the literature and rotary systems are most commonly used nowadays. Although the reported efficacy of these modalities is high, evidence shows that they are usually associated with a considerable risk of crack formation. In the present literature review, we have discussed the effects of rotary instrumentation and root canal preparation on dentinal crack formation based on evidence from the different studies in the literature. Our evidence showed that all of the investigated approaches to prepare root canals adequately can result in crack formation. The different rotary instrumentations also showed variable frequencies of developing dentinal cracks, and evidence from some comparative investigations shows that ProTaper modalities are associated with the least frequencies of the events. However, to make a solid conclusion for clinical practice, further research is still needed to validate our current evidence.

Apical Extrusion of Debris during Root Canal Preparation with ProTaper Next, WaveOne Gold and Twisted Files

(1) Background: Apical extrusion of debris is an example of a complication that may arise during root canal treatment, and it has been proven to be an unavoidable occurrence during endodontic treatment by numerous authors. Even though it may not hinder the long-term outcome of treatment, it may lead directly to increased levels of postoperative pain and, therefore, lower levels of patient acceptance and satisfaction. The aim of the study was to assess the weight of apically extruded debris during root canal preparation with instruments that use different movement kinematics (rotary, reciprocating, and adaptive motion); (2) Methods: The study was performed using the Myers and Montgomery model. Sixty human premolar teeth were inserted into preweighed Eppendorf tubes and randomly classified into three groups. After manual glide-path preparation, teeth in each group were instrumented to working length set 1 mm short of the anatomical apex using the standard sequence provided by the manufacturers (for Group 1: ProTaper Next X1 & X2; for Group 2: WaveOne Gold Primary, for Group 3: Twisted Files SM1-SM3). Root canals were irrigated with 1 mL of 0.9% NaCl solution between each file insertion. The tubes with collected debris were stored in an incubator at 70 °C for 5 days in order to evaporate the liquid component. Measurement of the weight of extruded debris was performed by subtracting the preinstrumentation from the postinstrumentation weight of the tubes. The results were analyzed with Kruskal–Wallis ANOVA, with significance level set at 0.05; (3) Results: The weight of extruded debris was 0.337 mg (SD = 0.148) for Group 1, 0.305 mg (SD = 0.201) for Group 2, and 0.348 mg (SD = 0.135) for Group 3. (4) Conclusions: Engine-driven root canal preparation with the use of instruments ProTaper Next, WaveOne Gold and Twisted Files that use different movement kinematics (rotary, reciprocating, and adaptive motion) was associated with apical extrusion of debris to a similar extent.