Present status and future directions - Removal of fractured instruments

Can antimicrobial photodynamic therapy serve as an effective adjunct protocol for disinfecting the necrotic root canal system? A randomized controlled study

BACKGROUND

Bacterial infection plays an important role in persistent periapical lesions and inadequate disinfection of root canals is considered the biggest factor responsible for endodontic treatment failure. Antimicrobial Photodynamic Therapy (aPDT) has become the latest choice to eradicate microorganisms in root canals.

OBJECTIVE

This study aims to evaluate the effectiveness of Antimicrobial Photodynamic Therapy (aPDT) in bacterial count reduction compared to Passive Ultrasonic Activation (PUI) and Ca(OH)2 dressings.

MATERIALS AND METHODS

Forty-five anterior single canal teeth with medium-sized periapical lesions (2-5 mm) were divided into three groups according to the disinfecting technique (each group consists of 15 canals with 1:1:1 allocation ratio): Group A: Ca(OH)2 dressing. Group B: Passive Ultrasonic Activation (PUI). Group C: Antimicrobial Photodynamic Therapy (aPDT). Direct bacterial viable count method was used to count the colonies forming units (CFU) before and after the disinfecting and the bacterial count reduction was estimated, the statistical analysis was performed at a 95% confidence level using the Chi-square and Mann-Whitney U test.

RESULTS

aPDT showed no statistically significant difference when compared to passive ultrasonic irrigation (P > 0.05) but showed higher and more promising results when compared to Ca(OH)2 dressings (P < 0.05).

CONCLUSIONS

aPDT has the ability and effectiveness as a disinfecting technique in necrotic and infected root canals.

CLINICAL SIGNIFICANCE OF THE STUDY

The results of this clinical trial provide that aPDT can be considered an adjunct method for root canal disinfection with the same effectiveness as passive ultrasonic irrigation.

Broken Instrument Removal Methods with a Minireview of the Literature

Instrument fracture in the root canal system is an unpleasant incident that may occur during root canal treatment. Comprehensive cleaning of the root canal system is often impossible in the presence of a broken instrument. Therefore, it is often imperative to remove the broken fragment from the root canal system. To date, various methods have been proposed for the removal of broken instruments from the root canal system. However, no consensus has been reached on a safe technique with a high success rate for broken instrument removal. This case series reports six cases of successful removal of broken instruments using different methods including the ultrasonic, tube-and-glue, tube-and-wire, tube-and-internal shaft, and the forceps techniques and also provides a brief review of the relevant literature.

Expert consensus on odontogenic maxillary sinusitis multi-disciplinary treatment

ABSTARCT

Odontogenic maxillary sinusitis (OMS) is a subtype of maxillary sinusitis (MS). It is actually inflammation of the maxillary sinus that secondary to adjacent infectious maxillary dental lesion. Due to the lack of unique clinical features, OMS is difficult to distinguish from other types of rhinosinusitis. Besides, the characteristic infectious pathogeny of OMS makes it is resistant to conventional therapies of rhinosinusitis. Its current diagnosis and treatment are thus facing great difficulties. The multi-disciplinary cooperation between otolaryngologists and dentists is absolutely urgent to settle these questions and to acquire standardized diagnostic and treatment regimen for OMS. However, this disease has actually received little attention and has been underrepresented by relatively low publication volume and quality. Based on systematically reviewed literature and practical experiences of expert members, our consensus focuses on characteristics, symptoms, classification and diagnosis of OMS, and further put forward multi-disciplinary treatment decisions for OMS, as well as the common treatment complications and relative managements. This consensus aims to increase attention to OMS, and optimize the clinical diagnosis and decision-making of OMS, which finally provides evidence-based options for OMS clinical management.

Navigating Separated Instrument Retrieval: A Case Report

Instrument separation during endodontic therapy is a complication occurring in 2% to 6% of cases. Focusing on the Masserann technique, the study presents a success rate of 55% in retrieving separated instruments. The technique's effectiveness is demonstrated through a case involving retrieving an instrument from the mandibular first premolar. The technique utilizes various tools, including trephine burs and an extractor, providing a reliable means to dislodge tightly wedged fragments. Despite limitations in specific tooth types and the necessity for frequent radiographic monitoring, the Masserann kit proves effective and underscores the importance of attempting retrieval before considering surgical interventions. The presented case exemplifies the technique's clinical applicability and positive outcomes in intricate scenarios, emphasizing its significance in endodontic practice.

Endodontic Retreatment of a Maxillary First Molar With Orthograde Retrieval of a Separated File by a Combination of Ultrasonic and File Braiding Techniques: A Case Report

The persistence of apical periodontitis after endodontic therapy can be attributed to biological causes or when the treatment approaches have proven insufficient in completely eradicating the intra-radicular infection. This case report describes the endodontic retreatment of a maxillary molar in which file separation occurred during the cleaning and shaping procedure. The separated file was successfully retrieved utilizing a combination of ultrasonic and braiding techniques. The field of ultrasonics has undergone a thorough investigation and has been demonstrated to be a conservative technique with minimal radicular dentin trephination. The braiding technique is also a conservative method that involves the use of several braided H-files to apply a gripping force, facilitating the extraction of foreign bodies. The utilization of this methodology has been documented in the endodontic academic literature.

Implications of root, pulp chamber, and canal anatomy on pulpotomy and revitalization procedures

OBJECTIVES

This review aims to discuss the implications of anatomy of the root, pulp chamber, and canals on pulpotomy and revitalization procedures (RPs) as treatment alternatives to root canal treatment procedures.

METHODS

This narrative review was undertaken to address two main questions - why remove vital pulp tissue in teeth with complex canal anatomy when it can be preserved? And why replace the necrotic pulp in teeth with mature roots with a synthetic material when we can revitalize? This review also aims to discuss anatomical challenges with pulpotomy and revitalization procedures.

RESULTS

Maintaining the vitality of the pulp via partial or full pulpotomy procedures avoids the multiple potential challenges faced by clinicians during root canal treatment. However, carrying out pulpotomy procedures requires a meticulous understanding of the pulp chamber anatomy, which varies from tooth to tooth. Literature shows an increased interest in the application of RPs in teeth with mature roots; however, to date, the relation between the complexity of the root canal system and outcomes of RPs in necrotic multi-rooted teeth with mature roots is unclear and requires further robust comparative research and long-term follow-up.

CONCLUSIONS

Whenever indicated, pulpotomy procedures are viable treatment options for vital teeth with mature roots; however, comparative, adequately powered studies with long-term follow-up are needed as a priority in this area. RPs show promising outcomes for necrotic teeth with mature roots that warrant more evidence in different tooth types with long-term follow-ups.  CLINICAL RELEVANCE: Clinicians should be aware of the pulp chamber anatomy, which is subject to morphological changes by age or as a defensive mechanism against microbial irritation, before practicing partial and full pulpotomy procedures. RP is a promising treatment option for teeth with immature roots, but more evidence is needed for its applications in teeth with mature roots. A universal consensus and considerably more robust evidence are needed for the standardization of RPs in teeth with mature roots.

The Management of Fractured Dental Instruments: A Case Series

The most common problem faced by dentists during root canal therapy is instrument separation. Instrument separation leads to the inefficient biomechanical preparation of the canals, which can affect the outcome of the root canal-treated tooth. Hence, bypassing the fractured instrument or removal can be accounted as a viable choice to maintain the structural integrity of the tooth. This article illustrates a case series wherein the fractured instrument was managed successfully with the use of conservative techniques.

Endodontic Orthograde Retreatments: Challenges and Solutions

Endodontic orthograde retreatments are considered one of the possible treatment options in case of post-treatment diseases considering the promising results present in the literature. Despite this, a plethora of articles have been published on this topic, and drawing conclusions could be challenging. For this reason, this review aims to summarize the crucial points on each aspect of non-surgical endodontic retreatments, discussing and comparing the current protocols, techniques, materials, and indications. Taking into consideration data from the literature, in terms of diagnosis, CBCT should be considered the first choice, since it can thoroughly affect the diagnosis and treatment plan. Regarding the procedural phases, some conclusions can be drawn: when present, coronal restoration materials such as crowns, partial prostheses, post, and core should be removed; the use of magnification devices, ultrasonic instruments, and an in-depth interpretation of radiographic images with both 2D and 3D images are strongly recommended during the orifice location; additional protocols such as irrigants activation, ultrasonic cleaning, and rotary or reciprocating instrumentation of treated canals are strongly recommended for filling materials removal and to achieve a high-quality chemo-mechanical disinfection; perforations should be treated as soon as possible, and the material of choice to treat them is the MTA or other calcium-silicate-based repair materials; the presence of ledges does not intrinsically reduce the success rate of RCRts if properly managed; in case of instrument fragments, their removal should be considered as the first treatment option, however many variables should be considered to select the proper technique or consider the option of bypassing.

The effect of the irrigant activation protocol on postoperative pain in maxillary incisors with asymptomatic apical periodontitis: A three-arm randomized clinical trial

OBJECTIVES

This study aimed to compare the effects of three irrigation activation systems (IAS) on postoperative pain (PP) in activating three final irrigants: sodium hypochlorite 5.25%, ethylenediaminetetraacetic acid 17%, and chlorhexidine 2%.

MATERIALS AND METHODS

This parallel randomized clinical trial included referred patients with asymptomatic large-sized apical lesion incisors. A standard method was followed in the canal cleaning and shaping for all included patients in the study. Then, the patients were randomly assigned (1:1 allocation) into three groups: G1 (n = 20) with passive ultrasonic irrigation activation; G2 (n = 20) with XP-Endo Finisher file activation; and G3 (n = 20) with diode laser (810 nm) activation. PP was estimated in all groups using a visual analog scale after 1, 3, 7, and 14 days of treatment. Comparisons between the groups were made using the Kruskal-Wallis test, whereas the Mann-Whitney U test was used in the pairwise comparisons.

RESULTS

Sixty patients were followed-up in this trial. There were significant differences between the groups in terms of PP After 1, 3, and 7 days of treatment (p = 0.002, p = 0.017, and p = 0.006, respectively). On the first day of treatment, G3 showed the lowest PP compared with G1 and G2 (p = 0.007 and p = 0.001, respectively). On the third day of treatment, G3 showed less PP compared with G2 (p = 0.005). On the seventh day of treatment, G2 showed the highest PP compared with G1 and G3 (p = 0.012 and p = 0.003, respectively).

CONCLUSIONS

The XP-Endo Finisher file caused the highest PP level especially in the next day and 3 days of the treatment, whereas the diode laser had the lowest PP level during the first week of treatment. It is noteworthy that PP disappeared completely after 2 weeks of treatment with all three IASs.

TRIAL REGISTRATION

The trial was registered in the ISRCTN registry (Trial ID: SRCTN99457940).

Comparative Evaluation of a Dynamic Navigation System versus a Three-dimensional Microscope in Retrieving Separated Endodontic Files: An In Vitro Study

INTRODUCTION

This study aimed to compare the effectiveness of a dynamic navigation system and a three-dimensional microscope in retrieving broken rotary Nickel-Titanium files when using trepan burs and the extractor system.

MATERIALS AND METHODS

Thirty maxillary first bicuspids with 60 separate roots were split into 2 comparable groups based on a comprehensive cone beam computed tomography analysis of the root length and curvature. After standardized access opening, glide paths, and patency attainment with the K file (sizes 10 and 15), the teeth were arranged on 3D models (three per quadrant, six per model). Subsequently, controlled-memory heat-treated Nickel-Titanium rotary files (#25/0.04) were notched 4 mm from the tips and fractured at the apical third of the roots. The C-FR1 Endo file removal system was employed under both guidance to retrieve the fragments, and the success rate, canal aberration, treatment time, and volumetric changes were measured. The statistical analysis was performed using IBM SPSS software at a significance level of 0.05.

RESULTS

The microscope-guided group had a higher success rate than the dynamic navigation system guidance, but the difference was insignificant (P > .05). In addition, the microscope-guided drills resulted in a substantially lower proportion of canal aberration, shorter time to retrieve the fragments and less change in the root canal volume (P < .05).

CONCLUSION

Although dynamically guided trephining with the extractor can retrieve separated instruments, it is inferior to three-dimensional microscope guidance regarding treatment time, procedural errors, and volume change.

The Good Old Masserann Technique for the Retrieval of a Separated Instrument: An Endodontic Challenge

Instrument separation is one of the most upsetting endodontic errors, and it can occur at any time during root canal surgery. A broken file causes a metallic restriction in the root canal and makes it difficult to clean and shape the instrument effectively, thereby making the prognosis questionable. Hence, such a fragment should be properly retrieved when it becomes difficult to bypass it. A variety of techniques and tools are utilized for instrument recovery; however, most of them are expensive, difficult to master, and technique-sensitive. One such tool for orthograde removal of intracanal metallic obstacles is the Masserann kit. We discuss a case involving file removal from the maxillary premolar by using the Masserann technique.

Removal of separated instruments from unfavourable locations: Case reports using the HBW ultrasonic ring or a surgical approach

Two patients were admitted to the dental clinic to evaluate two right mandibular first molars (both FDI no. 46). In Case 1, there was an accidental instrument separation, which was thought to have been bypassed; however, the instrument was located beyond the apical foramen, in the alveolar bone. The 1-week follow-up revealed that the fragment was close to the inferior alveolar nerve, thus allowing surgical removal to be performed. In Case 2, two separated instruments located in the apical third of the mesiobuccal and mesiolingual canals were removed using the HBW ultrasonic ring coupled to ISO 10 and 15 hand instruments. The 3-month and 1-year follow-ups (Case 1), and the 2-year and 3-year follow-ups (Case 2) showed a favourable evolution in both cases. It can be concluded that both the surgical approach and the HBW ultrasonic ring are viable options for the removal of separated instruments in unfavourable locations.

Endodontic Clinical Outcome after Separated Instrument Removal Using a Spinal Needle Technique: A Retrospective Study of Thirty Years of Clinical Experience

INTRODUCTION

Current methods for the removal of separated endodontic instruments (RSI) are not predictable.

METHODS

The primary outcome of this retrospective study was to assess the clinical and radiographic success (CRS) of teeth in case of RSI after a 5-year follow-up. Secondary outcomes were to evaluate (1) the effectiveness in RSI and (2) the risk of root fracture after RSI. The study protocol was registered at ClinicalTrials.gov (ID: NCT05128266). The patients were treated by the same endodontist between January 1991 and December 2019. The RSI was performed under the operative microscope as follows: first, the dentine surrounding the coronal part of the broken instrument was selectively removed by using a small ultrasonic tip to loosen the fragment; then, a modified spinal needle was used to catch and remove the instrument. The 1-, 3-, 5-, and >5-year CRS were recorded. Logistic regression analysis was performed to determine independent predictors of failure (ie, tooth number, type of root canal, shape of the root canal, type of broken instrument, apicocoronal level of the separated instrument, presence of periapical lesions, and root perforations).

RESULTS

A total of 158 teeth were included in this study. Finally, 131 instruments underwent RSI (82.9%). RSI was an independent predictor of CRS after 1-year of treatment (odds ratio: 58.3; 95% confidence interval: 27.42-95.73, P < .05). At the 5-year follow-up, only 10 of 131 teeth (7.6%) failed. All failures were caused by root fracture (10/10) (χ2 test, P < .05). Separated instruments located in the apical third of the root were more difficult to remove (13/49 cases, 26.5%; χ2 test, P < .05).

CONCLUSIONS

The proposed technique can achieve excellent effectiveness in RSI, can achieve a high CRS rate when a periapical lesion is present, is not associated to a significant increase in root fracture incidence, and should be performed with the help of an operative microscope.

Assessing Confidence Levels in Endodontic Procedures Among Senior Undergraduate Dental Students at Qassim University, Saudi Arabia: A Cross-Sectional Observational Study

Background This study aimed to determine the confidence of senior dental students in Qassim University's undergraduate dentistry program in Saudi Arabia regarding their capacity to perform endodontic procedures. The study's objective was to pinpoint areas of weakness and offer suggestions for potential improvement of endodontic and clinical training for dental students. Methodology Using anonymous survey forms, 120 senior dental students were surveyed. Students' self-reported levels of confidence in performing various endodontic procedures, such as periapical radiographs, rubber dam placement, endodontically treated tooth restoration, anesthesia, broken instrument removal, and endodontic retreatment, were studied in this survey. A Likert-style rating scale of 1 to 5 was used in the survey, with 1 denoting high confidence and 5 denoting low confidence. Results The majority of senior dental students at Qassim University reported high levels of confidence in taking periapical radiographs, with 64.04% indicating a high level of confidence. The second most assured field was rubber dam installation, with 47.6% of students expressing high levels of assurance. Confidence levels were noticeably lower during more difficult procedures such as endodontic retreatment and the removal of broken instruments. While 12% of students expressed high confidence in endodontic retreatment, only 3.46% of students expressed high confidence in removing broken instruments. According to Pearson's correlation (r = 0.352, p = 0.001), there was a significant and favorable correlation between competency level and confidence in performing various endodontic procedure-related steps. Conclusions The study's findings suggest that senior dentistry students at Qassim University might benefit from additional training and assistance in some endodontic treatment areas. The lack of confidence displayed during more challenging procedures, such as the removal of broken instruments and endodontic retreatment, demonstrates the need for additional training and supervision in such cases. The results of this study may be useful for educators in other dental colleges who wish to consider developing new teaching techniques, utilizing simulators and digital learning tools, and increasing opportunities for hands-on training and supervision to improve dental students' self-confidence and skills.

A review of the latest developments in rotary NiTi technology and root canal preparation

The introduction of nickel-titanium (NiTi) mechanical instruments dramatically changed clinical endodontics over the last few decades. Before NiTi, it was necessary to use more instruments to create an ideal root canal shape, and many approaches, sequences and techniques were developed over the years. Recently, NiTi endodontic instruments have undergone a series of changes brought about by modifications in design, surface treatments, and thermal treatments to improve their root canal preparation outcomes and reduce associated canal preparation risks during root canal treatment. Heat treatment is one of the most fundamental approaches to improving the fatigue resistance and flexibility of NiTi endodontic instruments. In addition, new kinematics have been developed to offer greater safety and efficiency. This narrative review describes the general properties and manufacturing of NiTi instruments, and the mechanical system evolution of NiTi instruments.

Opto-magnetic imaging spectroscopy in analyzing rotary NiTi endodontic instruments

Intra-canal fracture of rotary NiTi instruments occurs due to torsional stress, cyclic fatigue, or a combination of these two factors. Broken instruments are a serious obstacle to shaping, cleaning, and filling of the root canal and can adversely affect the outcome of endodontic therapy. The aim of this study was to examine the magnetic properties and ultrastructural changes of new, used, and fractured NiTi instruments using opto-magnetic imaging spectroscopy (OMIS). The study included three sets of different types of rotary instruments: MTwo (VDW, Munich, Germany), Pro Taper Universal (Dentsply Maillefer, Ballaigues, Switzerland), and BioRace (FKG DENTAIRE Swiss Dental Products, Le Crêt-du-Locle Switzerland). Root canal shaping was performed on root canals with different curvatures, and after intra-canal fracture, instruments of the same type (new, used, and fractured) were analyzed using OMIS at the Faculty of Mechanical Engineering, University of Belgrade. The obtained results showed a coincidence of peak localization for the used instruments that did not suffer a fracture, as well as for new, unused instruments of all examined groups. Additionally, there was a coincidence of peak intensities for new and fractured instruments in all groups. The specific treatment of electropolishing of the active surface of BioRace instruments caused a completely different electromagnetic response compared to conventional NiTi sets of tested instruments. New, unused BioRace instruments had the most pronounced positive (5.6078 n.a.u. x1000) and negative (-8.5218 n.a.u. x1000) intensity values. The analysis of NiTi instruments using opto-magnetic imaging spectroscopy indicated changes in the magnetic properties after their instrumentation.