3-Dimensional Accuracy of Dynamic Navigation Technology in Locating Calcified Canals

Comparison of selective laser melting and stereolithography etching templates for guided endodontics

Background

With the increasing application of guided endodontics to treat complex root canal treatment, the entire process of root canal treatment has become more precise, reducing damage to tooth structure and improving success rates. However, due to the limitations of the operating space, the use of guided endodontic templates in posterior root canal treatment is less common. This study aims to compare the accuracy and reliability of selective laser melting (SLM) and traditional stereolithography etching (SLA) guided endodontic templates for posterior root canals, providing better treatment strategies for posterior root canal treatment.

Methods

The teeth were randomly assigned to either SLM or SLA group. Preoperative cone-beam computed tomography (CBCT) and a three-dimensional (3D) scanner were used to establish the 3D root canal system and the accurate occlusal models of the teeth. The virtual access to the canal access was designed using Mimics 19.0 and 3-Matic 11.0. The endodontic access was performed based on either SLM or SLA templates. The accuracy of endodontic preparation was measured in three-dimensions by calculating deviations from planned accesses. The template height and tooth substance loss rates in each group were measured.

Results

SLM-guided templates have a low average deviation at the entry point and apical portion of the bur of total posterior teeth (including premolars and molars) and individual molars (P < 0.05). Moreover, there was a significant difference in angular deviations and height of template in total posterior teeth and individual molars (P < 0.05). The mean substance loss rate of the SLA group was slightly greater than that of the SLM group, but the difference was not statistically (P > 0.05).

Conclusions

SLM-guided endodontics provides a more predictable and precise location of root canal orifice for the treatment of posterior teeth.

Evaluation of a Novel Drilling Approach for Dynamic Navigation-Aided Endodontic Microsurgery: A Surgical Simulation Comparison Study

INTRODUCTION

This study investigated the feasibility of a novel drilling approach that integrates a pilot trephine into dynamic navigation (DN) for guided osteotomy and root-end resection (RER) with unimanual operation in endodontic microsurgery.

METHODS

Two operators with varying levels of DN experience performed guided osteotomy and RER using 2 unimanual drilling methods with DN-aided operation on 3-dimensional printed jaw models. Method 1 (M1) involved drilling with a conventional trephine. Method 2 (M2) involved drilling with a pilot trephine, followed by drilling with a conventional trephine. Accuracy, time, and safety of M1 and M2 were compared. Accuracy measurements included platform deviation (PD), end deviation (ED), angular deviation (AD), resection length deviation (RLD), and resection bevel angle (RBA). Additional parameters included osteotomy and RER time (OT) and bur slippage number (BSN). Statistical analyses were conducted using a 2-sample t-test or Mann-Whitney U test, with the significance level set at .05.

RESULTS

The PD, AD, RBA, and BSN in the M2 group were significantly less than in the M1 group (P < .05). For M1, the novice operator (NO) exhibited significantly higher values of PD, ED, OT, and BSN than the experienced operator (EO) (P < .05). For M2, the NO exhibited significantly higher value of ED only (P < .05), and drilling depth >7 mm was significantly associated with a longer OT (P < .05).

CONCLUSION

In this surgical simulation comparison study, the incorporation of a pilot drill improved the accuracy and safety of DN-aided endodontic microsurgery.

Does dynamic navigation system preserve more dentine? - A systematic review

OBJECTIVE

This systematic review aims to comparatively analyse the amount of dentin removal by free hand and static guided endodontics with dynamic navigation system (DNS) in endodontic access cavity preparation.

METHODS

The systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Based on the structured PICO framework of "Comparative evaluation of dynamic navigation system (I) to freehand (C) and static guided endodontics (C) in endodontic access cavity preparation on the preservation of tooth structure (O) when assessed on permanent human teeth (P)", the keywords were formulated and the articles were retrieved from three databases namely PubMed, Scopus and Embase, based on the keywords from the time of inception of DNS till June 2023. The risk of bias assessment was done using a modified Joanne Briggs Institute checklist, which evaluated domains such as randomisation, sample size, image acquisition using CBCT, angulation, accuracy and time taken. As the data was heterogenous, a quantitative meta-analysis was not performed.

RESULTS

Initially, 174 articles were retrieved from the three databases, 30 duplicates were removed, after title check 108 articles were excluded and following abstract check only 10 articles qualified for full text analysis. On reviewing the 10 full text articles, 5 articles were excluded and the remaining 5 articles were subjected to the risk of bias analysis which showed that 2 articles displayed low risk of bias and three articles showed high risk of bias. The RoB analysis revealed that only 2 studies evaluated the preservation of dentin in terms of accuracy, angulation and time taken proving the increased precision with minimal loss of tooth structure using DNS. In both the studies, DNS proved to be superior to free hand technique in terms of precision, accuracy and efficiency in locating the canals during access cavity preparation with maximal preservation of tooth structure.

CONCLUSION

With the minimal literature evidences, the present systematic review highlights maximal preservation of dentin using DNS. However, further invitro and invivo studies comparing the free hand, static guided endodontics to DNS must be carried out for its translation into clinical practice.

CLINICAL SIGNIFICANCE

Dynamic navigation system provides maximal preservation of dentin during access cavity preparation.

The Use of Artificial Intelligence in Endodontics

Endodontics is the dental specialty foremost concerned with diseases of the pulp and periradicular tissues. Clinicians often face patients with varying symptoms, must critically assess radiographic images in 2 and 3 dimensions, derive complex diagnoses and decision making, and deliver sophisticated treatment. Paired with low intra- and interobserver agreement for radiographic interpretation and variations in treatment outcome resulting from nonstandardized clinical techniques, there exists an unmet need for support in the form of artificial intelligence (AI), providing automated biomedical image analysis, decision support, and assistance during treatment. In the past decade, there has been a steady increase in AI studies in endodontics but limited clinical application. This review focuses on critically assessing the recent advancements in endodontic AI research for clinical applications, including the detection and diagnosis of endodontic pathologies such as periapical lesions, fractures and resorptions, as well as clinical treatment outcome predictions. It discusses the benefits of AI-assisted diagnosis, treatment planning and execution, and future directions including augmented reality and robotics. It critically reviews the limitations and challenges imposed by the nature of endodontic data sets, AI transparency and generalization, and potential ethical dilemmas. In the near future, AI will significantly affect the everyday endodontic workflow, education, and continuous learning.

Artificial Intelligence in Endodontic Education

AIMS

The future dental and endodontic education must adapt to the current digitalized healthcare system in a hyper-connected world. The purpose of this scoping review was to investigate the ways an endodontic education curriculum could benefit from the implementation of artificial intelligence (AI) and overcome the limitations of this technology in the delivery of healthcare to patients.

METHODS

An electronic search was carried out up to December 2023 using MEDLINE, Web of Science, Cochrane Library, and a manual search of reference literature. Grey literature, ongoing clinical trials were also searched using ClinicalTrials.gov.

RESULTS

The search identified 251 records, of which 35 were deemed relevant to artificial intelligence (AI) and Endodontic education. Areas in which AI might aid students with their didactic and clinical endodontic education were identified as follows: 1) radiographic interpretation; 2) differential diagnosis; 3) treatment planning and decision-making; 4) case difficulty assessment; 5) preclinical training; 6) advanced clinical simulation and case-based training, 7) real-time clinical guidance; 8) autonomous systems and robotics; 9) progress evaluation and personalized education; 10) calibration and standardization.

CONCLUSIONS

AI in endodontic education will support clinical and didactic teaching through individualized feedback; enhanced, augmented, and virtually generated training aids; automated detection and diagnosis; treatment planning and decision support; and AI-based student progress evaluation, and personalized education. Its implementation will inarguably change the current concept of teaching Endodontics. Dental educators would benefit from introducing AI in clinical and didactic pedagogy; however, they must be aware of AI's limitations and challenges to overcome.

Dynamically guided transantral piezoelectric endodontic microsurgery: A case report with technical considerations

AIM

Endodontic microsurgery (EMS) of maxillary molars may represent a complex challenge to the clinician due to the location of the roots and the proximity of the maxillary sinus floor. This report aimed to describe the simultaneous use of a computer-assisted dynamic navigation (C-ADN) system and piezoelectric bony-window osteotomy for the transantral microsurgical approach of a maxillary left first molar with adequate root canal filling and symptomatic apical periodontitis.

SUMMARY

This case report highlights the importance of C-ADN to carry out a minimally invasive buccal surgical access to palatal roots affected by apical periodontitis and provides a practical example to help clinicians make treatment decisions based on the available evidence. Clinical and tomographic evaluations were performed before the surgical procedure and at 24-month follow-up. This case was treated using a C-ADN system fitted to a piezotome for the buccal approach of the buccal roots, maxillary sinus membrane lifting, and for transantral location, root-end resection, cavity preparation, and filling of the palatal root. The navigation system allowed to achieve an accurate apical canal terminus location and root-end filling of the three roots with a minimally invasive piezoelectric crypt approach. At the 24-month follow-up examination, the patient remains asymptomatic, with normal periapical structures, and regeneration of maxillary sinus walls. It was concluded that the combination of dynamic navigation with piezoelectric bony-window osteotomy offers enhanced accuracy, tissue preservation, diminished risk of iatrogenic complications, and could maximize success and survival rates in transantral EMS.

The Use of Dynamic Navigation Systems as a Component of Digital Dentistry

The development of dynamic navigation system (DNS) has facilitated the development of modern digital medicine. In the field of dentistry, the cutting-edge technology is garnering widespread recognition. Based on the principles of 3-dimensional visualization, virtual design, and precise motion tracking, DNS is mainly composed of a computer, a tracking system, specialized tracer instruments, and navigation software. DNS employs a workflow that begins with preoperative data acquisition and imaging data reconstruction, followed by surgical instrument calibration and spatial registration, culminating in real-time guided operations. Currently, the system has been applied in a broad spectrum of dental procedures, encompassing dental implants, oral and maxillofacial surgery (such as tooth extraction, the treatment of maxillofacial fractures, tumors, and foreign bodies, orthognathic surgery, and temporomandibular joint ankylosis surgery), intraosseous anesthesia, and endodontic treatment (including root canal therapy and endodontic surgery). These applications benefit from its enhancements in direct visualization, treatment precision, efficiency, safety, and procedural adaptability. However, the adoption of DNS is not without substantial upfront costs, required comprehensive training, additional preparatory time, and increased radiation exposure. Despite challenges, the ongoing advancements in DNS are poised to broaden its utility and substantially strengthen digital dentistry.

Is Augmented Reality Technology Effective in Locating the Apex of Teeth Undergoing Apicoectomy Procedures?

This study seeks to assess the accuracy of apical location using an augmented reality (AR) device with a free-hand method. Sixty (60) osteotomy site preparations were randomly assigned to one of two study groups: A. AR device (AR) (n = 30), and B. conventional free-hand method (FHM) (n = 30). Preoperative CBCT scans and intraoral scans were taken and uploaded to specialized implant-planning software to virtually plan preparations for the apical location osteotomy sites. The planning software was then used to automatically segment the teeth in each experimental model for their complete visualization using the AR device. A CBCT scan was carried out postoperatively after conducting the apical location procedures. The subsequent datasets were imported into therapeutic software to analyze the coronal, apical, and angular deviations. The Mann-Whitney non-parametric test was used. There were no statistically significant differences identified at the coronal (p = 0.1335), apical (p = 0.2401), and angular deviations (p = 0.4849) between the AR and FHM study groups. The augmented reality technique did not show a statistically significant accuracy of osteotomies for apical location when compared with the conventional free-hand method.

Limitations and Management of Dynamic Navigation System for Locating Calcified Canals Failure

Nonsurgical endodontic teeth treatment with severe pulp canal obliteration poses challenges, primarily locating canals. By combining 3-dimensional reconstruction and spatial location registration, the dynamic navigation technique uses an optical tracking system to guide the clinician to drill in real time according to the predesigned path until access to the canal is established. Several in vitro studies and case reports have shown that calcified canal location with dynamic navigation system (DNS) is more accurate and efficient, yet the technique has limitations. In 4 cases with 7 teeth, this work presents manipulation process and clinical outcomes of DNS helping in calcified canal location. We performed handpiece adaptation and elucidated the failure to locate the canals with DNS in 2 teeth, resulting in canal geometry alteration and canal path deviation. Subsequently, the more experienced endodontist located the canals by combining cone-beam computed tomographic imaging and dental operating microscopy. All patients were completely asymptomatic after treatment. At the 1-year follow-up visit, the bone healing of periapical lesions progressed well according to the periapical radiography or cone-beam computed tomographic imaging. These findings indicate that DNS is a promising technique for locating calcified canals; however, it needs to be refined before clinical use.

Expert consensus on digital guided therapy for endodontic diseases

Digital guided therapy (DGT) has been advocated as a contemporary computer-aided technique for treating endodontic diseases in recent decades. The concept of DGT for endodontic diseases is categorized into static guided endodontics (SGE), necessitating a meticulously designed template, and dynamic guided endodontics (DGE), which utilizes an optical triangulation tracking system. Based on cone-beam computed tomography (CBCT) images superimposed with or without oral scan (OS) data, a virtual template is crafted through software and subsequently translated into a 3-dimensional (3D) printing for SGE, while the system guides the drilling path with a real-time navigation in DGE. DGT was reported to resolve a series of challenging endodontic cases, including teeth with pulp obliteration, teeth with anatomical abnormalities, teeth requiring retreatment, posterior teeth needing endodontic microsurgery, and tooth autotransplantation. Case reports and basic researches all demonstrate that DGT stand as a precise, time-saving, and minimally invasive approach in contrast to conventional freehand method. This expert consensus mainly introduces the case selection, general workflow, evaluation, and impact factor of DGT, which could provide an alternative working strategy in endodontic treatment.

Dynamic Navigation System vs. Free-Hand Approach in Microsurgical and Non-Surgical Endodontics: A Systematic Review and Meta-Analysis of Experimental Studies

(1) Background: A Dynamic Navigation System (DNS) is an innovative tool that facilitates the management of complex endodontic cases. Despite the number of advantages and limitations of this approach, there is no evidence-based information about its efficiency in comparison with that of the traditional method in endodontics. (2) Objectives: We aimed to explore any beneficial effects of the DNS and compare the outcomes of DNS vs. free-hand (FH) approaches for non-surgical and microsurgical endodontics. (3) Methods: A literature search was conducted in August 2023 to identify randomized, experimental, non-surgical, and microsurgical endodontic studies that compared the DNS with FH approaches. The procedural time (ΔT, s), substance loss (ΔV, mm3), angular deviation (ΔAD, °), coronal/platform linear deviation (ΔLD_C, mm), and apical linear deviation (ΔLD_A, mm) were recorded and analyzed. Quality and risk of bias assessments were conducted according to the Quality Assessment Tool For In Vitro Studies. A meta-analysis was performed using mean difference and standard deviation for each outcome, and heterogeneity (I2) was estimated. p < 0.05 was considered significant. (4) Results: One-hundred and forty-six studies were identified following duplicate removal, and nine were included in the systematic review and meta-analysis. The overall risk of bias was classified as low. The DNS was found to be more accurate and efficient than the FH approach was, resulting in a significantly shorter operation time (p < 0.00001) and less angular (p ≤ 0.0001) and linear deviation (p ≤ 0.01). For substance loss, the advantage of the DNS was significant only for microsurgery (p = 0.65, and p < 0.005, for non-surgical and microsurgical procedures, respectively). A reduced risk of iatrogenic failure using the DNS was observed for both expert and novice operators. (5) Conclusions: The DNS appears beneficial for non-surgical and microsurgical endodontics, regardless of the operator's experience. However, appropriate training and experience are necessary to access the full advantages offered by the DNS.

Age-related changes in the morphology of the root canal system of mandibular first molars: a micro-CT study

OBJECTIVE

This study aimed to evaluate changes on root canal morphology in patients with different ages using micro-CT technology.

MATERIALS AND METHODS

Mandibular first molars (n = 150) were scanned at a pixel size of 13.68 µm, categorized into 3 groups according to patient's age and analyzed regarding configuration, orifices, apical foramina, root length, canal volume, and surface area. Morphological 2D and 3D parameters were evaluated in distal roots with Type I configuration (n = 109) as well as the morphology of isthmuses Types I and III in 68 mesial roots. One-way ANOVA post hoc Tukey and Kruskal-Wallis tests were used for statistical analyses (α = 5%).

RESULTS

A great variation in the canal configuration was found. No difference was observed in roots' length (p > 0.05). Canal volume reduced with age (p < 0.05), while surface area increased (p < 0.05) in patients ≤ 30 years. There was no difference in canal/root length, area, and from foramen to the apex in distal roots with Type I configuration (p > 0.05), but 2D and 3D parameters significantly decreased with age (p < 0.05). Overall, the diameter of the isthmuses' roof reduced with age (p < 0.05). In patients ≥ 31 years with Type III isthmus the distance from the isthmus floor to the foramen of the mesiolingual canal also decreased (p < 0.05).

CONCLUSION

Overall, the internal morphology of the mesial roots of mandibular first molars was more affected by aging than distal canals. The most relevant tested parameter that significantly reduced in both roots was the volume of the root canal systems.

CLINICAL RELEVANCE

A detailed evaluation of fine anatomical aspects of the root canal system of mandibular first molars of patients with different ages showed that the internal morphology of mesial roots is more affected by aging than distal canals.

Current Applications of Dynamic Navigation System in Endodontics: A Scoping Review

This scoping review (SCR) was conducted to map the existing literature on dynamic navigation system (DNS), to examine the extent, range, and nature of research activity. Additionally, this SCR disseminates research findings, determines the value of conducting a full systematic review with meta-analysis, and identifies gaps in the existing literature and future directions. This SCR followed Arksey and O'Malley's five stages framework. The electronic search was performed in PubMed (Medline), Scopus (Elsevier), and Web of Science (Clarivate Analytics) databases using a search strategy. Five themes emerged during the descriptive analysis that captured the DNS application in endodontics. The DNS has been explored for creating access cavities (8/18, 44.44%), locating calcified canals (4/18, 22.2%), microsurgery (3/18, 16.6%), post removal (2/18, 11.1%), and intraosseous anesthesia (1/18, 5.5%). Out of the 18 studies included, 12 are in vitro (66.6%), five are in vivo (case report) (27.7%), and one is ex vivo (5.5%). The DNS demonstrated accuracy and efficiency in performing minimally invasive access cavities, locating calcified canals, and performing endodontic microsurgery, and it helped target the site for intraosseous anesthesia.

Effect of field of view and voxel size on CBCT-based accuracy of dynamic navigation in endodontic microsurgery: an in vitro study

INTRODUCTION

This study aimed to evaluate the influence of field of view (FOV) and voxel size on the accuracy of dynamic navigation (DN)-assisted endodontic microsurgery (EMS).

METHODS

Nine sets of maxillary and mandibular three-dimensional-printed jaw models composed of 180 teeth were divided into nine groups with different FOVs (80 × 80 mm, 60 × 60 mm, and 40 × 40 mm) and voxel sizes (0.3, 0.16, and 0.08 mm). The endodontic DN system was used to plan and execute the EMS. The accuracy of the DN-EMS was represented by the platform deviation, end deviation, angular deviation, resection angle, and resection length deviation. Statistical analyses were performed using SPSS 24.0, and the significance level was set at p < 0.05.

RESULTS

The average platform, end, angular, resection angle, and resection length deviation were 0.69 ± 0.31 mm, 0.93 ± 0.44 mm, 3.47 ± 1.80°, 2.35 ± 1.76°, and 0.41 ± 0.29 mm, respectively. No statistically significant differences in accuracy were observed between the nine FOV and voxel size groups.

CONCLUSION

FOV and voxel size did not appear to play an important role in the accuracy of DN-EMS. Considering the image quality and radiation dose, it is reasonable to select a limited FOV (such as 40 × 40 mm and 60 × 60 mm) to cover only the registration device, involved teeth, and periapical lesion. The voxel size should be selected according to the required resolution and CBCT units.

Analysis of the Accuracy of a Dynamic Navigation System in Endodontic Microsurgery: A Prospective Case Series Study: Accuracy of DNS in EMS

OBJECTIVES

To evaluate the accuracy of a dynamic navigation system (DNS) for guided osteotomy and root-end resection during endodontic microsurgery (EMS) and assess its prognosis.

METHODS

Nine patients who met inclusion criteria underwent DNS-guided EMS. Osteotomy and root-end resection were performed with assistance of DNS (DHC-ENDO1, DCARER Medical Technology, Suzhou, China). The preoperative virtually planned path and postoperative cone-beam computed tomography images were superimposed using DNS software. Accuracy was assessed based on deviations in the platform, apex, and angle of the osteotomy, as well as in the length and angle of the root-end resection. Follow-up evaluations were performed after at least a year postoperatively.

RESULTS

Among the nine patients (11 teeth with 12 roots), the mean platform, apex, and angular deviation of the osteotomy were 1.05 mm, 1.2 mm, and 6.24°, respectively. The mean length and angle deviation of the root-end resection were 0.46 mm and 4.9°, respectively. Significant differences were observed according to tooth position. The platform and apex deviated significantly less in the posterior than in the anterior teeth (p < .05). No significant differences were observed according to arch type, side, and depth of the surgical path (p > .05). Eight patients were evaluated after at least a year postoperatively; clinical and radiographic evaluation revealed a 90% success rate (9/10 teeth).

CONCLUSIONS

This study demonstrated high accuracy of DNS in EMS. Furthermore, DNS-guided EMS had a success rate similar to that of freehand EMS over a short-term follow-up. Further study with a larger sample size is necessary.

CLINICAL SIGNIFICANCE

The present novel DNS technology is a viable method for guided osteotomy and root-end resection in EMS.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR2100042312.

Guided Endodontic Surgery: A Narrative Review

Background and objectives: Endodontic surgery has evolved over the last two decades. The use of state-of-the-art guided endodontic surgical procedures produces a predictable outcome in the healing of lesions of endodontic origin. The main objective of this review paper is to define and characterize guided surgical endodontics as well as its benefits and drawbacks by reviewing the most recent relevant scientific literature. Methods: A literature search was conducted using multiple databases comprising of MEDLINE (via PubMed), EMBASE, and Web of Science. The terms used for the search were ‘guided endodontics’, ‘surgical endodontics’, and ‘endodontic microsurgery’. Results: In total, 1152 articles were obtained from the analysis of the databases. Unrelated articles from the available full text of 388 articles were excluded. A total of 45 studies were finally included in the review. Conclusions: Surgical-guided endodontics is a relatively new area of study that is still maturing. It has many applications such as root canal access and localization, microsurgical endodontics, endodontic retreatment, and glass fiber post removal. Additionally, it does not matter how experienced the operator is; the procedure can be completed for the patient in less time and provides greater accuracy and safety than conventional endodontics.

Real-time guided endodontics: A case report of maxillary central incisor with calcific metamorphosis

Dental trauma results in various complications and poses an enigma to the practitioner. Calcific metamorphosis is one of the sequelae of trauma. A female patient of 35 years visited the specialty clinic of endodontics for the management of a discolored tooth. Clinically, discolored 21 was observed with no pain on palpation and percussion. The pulp sensibility test revealed a negative response. Radiographic examination revealed pulp canal obliteration with an apical radiolucency of Peri Apical Index (PAI 4). The tooth was diagnosed as necrotic pulp with asymptomatic apical periodontitis. Attempt to negotiate the canal under a Dental Operating Microscope (LABOMED, Los Angeles, CA, USA) and ultrasonics (Satelec, Acteon, France) was futile. Cone-beam computed tomography image revealed a patent canal in the apical third. Using real-time guided endodontics with a dynamic navigation system (Navident, ClaroNav, Toronto, ON, Canada), the protocol of plan, trace, and place was followed, and successful canal negotiation was achieved. After radiographic confirmation, root canal treatment was completed.

Evaluation of a dynamic navigation system for endodontic microsurgery: study protocol for a randomised controlled trial

INTRODUCTION

Endodontic microsurgery is a very important technique for preserving the natural teeth. The outcomes of endodontic microsurgery largely depend on the skill and experience of the operators, especially for cases in which the apices are located far away from the labial/buccal cortical bone. A dynamic navigation system (DNS) could provide a more accurate and efficient way to carry out endodontic microsurgery. This study is devoted to comparing the clinical outcomes of the DNS technique with those of the freehand technique.

METHODS AND ANALYSIS

Sixteen patients will be randomly assigned to one of two groups. For the experimental group, the osteotomy and root-end resection will be performed under the guidance of dynamic navigation. For the control group, these procedures will be performed freehand by an endodontist. The required time to perform these procedures will be used to evaluate the efficiency of the DNS technique. A Visual Analogue Scale will be used to evaluate pain at 1, 3 and 7 days after endodontic microsurgery. Preoperative and postoperative cone beam CT scans will be obtained to evaluate the accuracy of the DNS technique. The global coronal deviations, the apical deviations and the angular deflection will be measured. The root-end resection length deviation, the root-end resection angle deviations, the extent of the osteotomy and the volume change of the buccal cortical bone will also be measured. Periapical radiographs will be obtained to evaluate the outcome at 1 year after microsurgery. The time to execute the study, including follow-ups, will last from 1 June 2022 to 31 December 2025.

ETHICS AND DISSEMINATION

The present study has received approval from the Ethics Committee of Peking University School and Hospital of Stomatology. The results will be disseminated through scientific journals.

TRIAL REGISTRATION NUMBER

ChiCTR2200059389.

Guided Endodontics: A Literature Review

The main objective of this paper is to perform an updated literature review of guided endodontics based on the available up-to-date scientific literature to identify and describe the technique, its benefits, and its limitations. Four electronic databases (PubMed, Scopus, Science Direct, and Web of Science) were used to perform a literature search from 1 January 2017 to 13 May 2022. After discarding duplicates, out of 1047 results, a total of 29 articles were eligible for review. Guided endodontics is a novel technique that is currently evolving. It is applied in multiple treatments, especially in accessing and locating root canals in teeth with pulp canal obliteration, microsurgical endodontics, and removing glass fiber posts in endodontic retreatments. In addition, it is independent of an operator's experience, requires less treatment time for the patient, and is more accurate and safer than conventional endodontics.

Present status and future directions - Guided endodontics

Luxation injuries and other stimuli may lead to a pulp canal obliteration (PCO). Even though the apposition of tertiary dentine is a sign of a vital pulp, in some cases root canal treatment is indicated in the long term due to apical periodontitis or pulpitis. Depending on the extent of PCO, root canal treatment may be challenging even for experienced and well-equipped endodontic specialists. The 'guided endodontics' (GE) technique was introduced 6 years ago as an alternative to conventional access cavity preparation for teeth with PCO and apical pathosis or irreversible pulpitis. Using three-dimensional radiological imaging such as cone-beam computed tomography and a digital surface scan, an optimal access to the orifice of the calcified root canal can be planned virtually with appropriate software. GE is implemented either with the help of templates analogous to guided implantology (= static navigation) or by means of dynamic navigation based on a camera-marker system. GE has emerged as a field of research in the last 6 years with very promising laboratory-based results regarding the accuracy of guided endodontic access cavities for both static and dynamic navigation. Clinical implementation seems to provide favourable results, but the evidence is mainly based on numerous case reports and a few case series. This narrative review aims to provide an update on the present status of GE and to identify relevant research areas that could contribute to further improvements of this technique.

Guided Endodontics: Static vs. Dynamic Computer-Aided Techniques—A Literature Review

(1) Background: access cavity preparation is the first stage of non-surgical endodontic treatment. The inaccuracy of this step may lead to numerous intraoperative complications, which impair the root canal treatment’s prognosis and therefore the tooth’s survival. Guided endodontics, meaning computer-aided static (SN) and dynamic navigation (DN) techniques, has recently emerged as a new approach for root canal location in complex cases. This review aims to compare SN and DN guided endodontics’ techniques in non-surgical endodontic treatment. (2) Methods: an electronic search was performed on PubMed, Scopus, and Cochrane Library databases until October 2021. Studies were restricted by language (English, Spanish and Portuguese) and year of publication (from 2011 to 2021). (3) Results: a total of 449, 168 and 32 articles were identified in PubMed, Scopus, and Cochrane Library databases, respectively, after the initial search. Of the 649 articles, 134 duplicates were discarded. In this case, 67 articles were selected after title and abstract screening, of which 60 were assessed for eligibility through full-text analysis, with one article being excluded. Four cross-references were added. Thus, 63 studies were included. (4) Conclusions: guided endodontics procedures present minimally invasive and accurate techniques which allow for highly predictable root canal location, greater tooth structure preservation and lower risk of iatrogenic damage, mainly when performed by less experienced operators. Both SN and DN approaches exhibit different advantages and disadvantages that make them useful in distinct clinical scenarios.

Comparison of the accuracy and efficiency of a 3D dynamic navigation system for osteotomy root-end resection performed by novice and experienced endodontists

AIM

To investigate whether the 3D-dynamic navigation system (3D-DNS) can improve experienced endodontists' (EEs') and novice endodontists' (NEs') accuracy and efficiency in osteotomy and root-end resection (RER) and to verify that the 3D-DNS enables NEs to perform osteotomy and RER as accurately and efficiently as EEs.

METHODS

Seventy-six roots in cadaver heads were randomly divided into four groups: 3D-DNS-NE, 3D-DNS-EE, Freehanded (FH)-NE, and FH-EE (all, n=19). CBCT scans were taken pre- and postoperatively. Osteotomy and RER were planned virtually in the X-guided software (X-Nav Technologies, Lansdale). Accuracy was calculated by measuring the 2D and 3D virtual deviations and angular deflection (AD) using superimposing software (X-Nav technologies). Efficiency was determined by time of operation and the number of mishaps.

RESULTS

Accuracy deviations were significantly less in the 3D-DNS-EE group than in the FH-EE group (p<.05). We found lessened 2D and 3D accuracy deviations comparing the 3D-DNS-NE group to the FH-NE group (p<.05). The time required for osteotomy and RER with the 3D-DNS was ∼ ½ of that required for the FH method for both EEs and NEs (p<.05). We found no difference in the number of mishaps between the 3D-DNS and FH groups for EEs and NEs (p>.05).

CONCLUSIONS

The 3D-DNS improved EEs' and NEs' accuracy and efficiency in osteotomy and RER. The NEs were as efficient as the EEs using 3D-DNS. Notably, the 3D-DNS improved the NEs' accuracy compared to FH method but the 3D-DNS did not enable the NEs to perform osteotomy and RER as accurately as the EEs.

REAL-TIME 3D IMAGE-GUIDED NAVIGATION SYSTEM IN ENDODONTIC MICROSURGERY - A CADAVER STUDY

INTRODUCTION

This study evaluated the accuracy and efficiency of 3D Dynamic Navigation System (3D-DNS) to perform minimally invasive osteotomy (MIO) and root-end resection (RER) in endodontic microsurgery (EMS) and investigated the viability of root-end cavity preparation (RECP) and fill (REF) in MIO.

METHODS

We divided 48 tooth roots in cadaver heads into two groups: 3D-DNS (n = 24) and freehand (n = 24). Cone beam computed tomography (CBCT) scans were taken before and after surgery. First, we verified virtual 3D-DNS accuracy using three outcome measures: 2D and 3D virtual deviations and angular deflection (AD). Second, we investigated 3D-DNS's accuracy for performing MIO in two outcome measures: Osteotomy size and volume. Third, we determined the 3D-DNS accuracy for RER in three outcomes: Resected root length, root length after resection, and resection angle. We investigated the viability of RECP and REF and measured REF depth and volume, as well, recording procedural times and number of mishaps.

RESULTS

2D and 3D virtual deviations and AD were lower in the 3D-DNS than FH (p<.05). Osteotomy height, length, and volume were all reduced when using 3D-DNS (p < .05). The resection angle was lower for the 3D-DNS (p<.05). RECP and REF were completed in 100% of the roots. The REF depth achieved was ∼ 3mm. Osteotomy time, RER time, and total procedure time were all significantly shortened using 3D-DNS (p < .05).

CONCLUSIONS

3D-DNS enabled our surgeon to perform accurate and efficient EMS with minimally invasive osteotomy and RER. The surgeon was also able to conduct RECP with adequate REF in minimally invasive osteotomy performed using 3D-DNS guidance.

Application of computer-assisted dynamic navigation in complex root canal treatments: Report of two cases of calcified canals

Root canal treatment and non-vital bleaching of teeth with pulp canal obliteration may represent a complex challenge to the clinician. This report describes the usefulness of the computer-assisted dynamic navigation system for the root canal treatment of two cases of teeth with a history of traumatic injury, extensively obliterated root canals and crown discoloration. Clinical and cone-beam computed tomographic evaluations were completed prior to procedures and 12 months after treatment. Both cases were treated using a computer-assisted dynamic navigation system coupled to a high-speed handpiece in order to establish the location and orientation of the partially obliterated canal and endodontic access route planning. The system allowed an accurate localisation of the root canal with a conservative access cavity. At the 12-month recall examination, the patients continue to be symptom-free, with a normal appearance of the mucogingival complex, adequate restoration of the tooth colour and intact periapical structures.

[In vitro evaluation of positioning accuracy of trephine bur at different depths by dynamic navigation]

OBJECTIVE

To evaluate the accuracy of trephine bur drilling at different depths guided by dynamic navigation system in 3D printing in vitro model.

METHODS

A model at the depth of 5 mm, 10 mm, and 15 mm from the outer surface of which hemispherical cavities was reserved and the 3D printing technology was used to make the standardized model with Veroclear resin. The cone beam CT (CBCT) was taken and the data were imported into the dynamic navigation software (DCARER, China) to establish navigation path programming. Under the guidance of dynamic navigation, a trephine bur with a diameter of 4.5 mm was used to complete the access operation. At each depth, 10 approaches were completed. The postoperative model CBCT was taken. The approach trajectory under navigation was reconstructed and compared with the designed path. The two-dimensional distance deviation, depth deviation, three-dimensional distance deviation, and angle deviation between the actually prepared path and the designed path were calculated.

RESULTS

At the depth of 5 mm, the two-dimensional distance deviation between the end position of the prepared path and the designed path was (0.37±0.06) mm, the depth deviation was (0.06±0.05) mm, the three-dimensional distance deviation was (0.38±0.07) mm, and the angle deviation was 2.46°±0.54°; At the depth of 10 mm, the four deviations between the end position of prepared path and the designed path were (0.44±0.05) mm, (0.16±0.06) mm, (0.47±0.05) mm, and 2.45°±1.21°, respectively; At the depth of 15 mm, the four deviations were (0.52±0.14) mm, (0.16±0.07) mm, (0.55±0.15) mm, and 3.25°±1.22°, respectively. With the increase of entry depth, the three-dimensional and depth accuracy of dynamic navigation system decreased (P < 0.01), and the positioning angle deviation had no relation with the entry depth (P>0.01).

CONCLUSION

Dynamic navigation technology can achieve high positioning accuracy in the depth range of 15 mm, but its deviation increases with the increase of entry depth.

Present status and future directions - Minimal endodontic access cavities

In the last decades, the move of Medicine towards minimally invasive treatments is notorious and scientifically grounded. As Dentistry naturally follows its footsteps, minimal access preparation also became a trend topic in the endodontic field. This procedure aims to maximize preservation of dentine tissue, backed up by the idea that this is an effective way to reduce the incidence of post-treatment tooth fracture. However, with the assessment of the body of evidence on this topic, it is possible to observe some key-points (a) the demand for nomenclature standardization, (b) the requirement of specific tools such as ultra-flexible instruments, visual magnification, superior illumination, and three-dimensional imaging technology, (c) minimally invasive treatment does not seem to affect orifice location and mechanical preparation when using adequate armamentarium, but it (d) may impair adequate canal cleaning, disinfection, and filling procedures, and also (e) it displays contradictory results regarding the ability to increase the tooth strengthen compared to the traditional access cavity. In spite of that, it is undeniable that methodological flaws of some benchtop studies using extracted teeth may be responsible for the conflicting data, thus triggering the need for more sophisticated devices/facilities and specifically designed research in an attempt to make it clear the role of the access size/design on long-term teeth survival. Moreover, it is inevitable that a clinical approach like minimal endodontic access cavities that demands complex tools and skilled and experienced operators bring to the fore doubts on its educational impact mainly when confronted with the conflicting scientific output, ultimately provoking a cost-benefit analysis of its implementation as a routine technique. In addition, this review discusses the ongoing scientific and clinical status of minimally invasive access cavities aiming to input an in-depth and unbiased view over the rationale behind them, uncovering not only the related conceptual and scientific flaws, but also outlining future directions for research and clinical practices. The conclusions attempt to skip from passionate disputes highlighting the current body of evidence as weak and incomplete to guide decision making, demanding the development of a close-to-in-situ laboratory model or a large and well-controlled clinical trial to solve this matter.

Dens invaginatus: clinical implications and antimicrobial endodontic treatment considerations

Dens invaginatus or dens in dente is a developmental dental anomaly resulting from an invagination of the enamel organ into the dental papilla during odontogenesis. Radiographically, it is usually seen as a radiolucent invagination surrounded by a radiopaque area (enamel) limited to the tooth crown or extending into the root. Because the invagination is opened to the oral cavity, it can retain saliva, food remnants, and bacteria. In conditions that the enamel lining of the invagination is naturally absent or lost due to caries, bacterial cells and products can diffuse from the invagination through the dentin tubules to reach the pulp and cause disease. Management of teeth with dens invaginatus include preventive sealing or filling of the invagination, or, if the pulp is affected, therapeutical options include vital pulp therapy, nonsurgical root canal treatment, apexification or regenerative endodontic procedures, periradicular surgery, intentional replantation, or extraction. It is recommended that the invagination be always approached, regardless of the type of dens invaginatus. The root canal should be treated whenever the pulp is irreversibly inflamed or necrotic. Endodontic management of teeth with dens invaginatus is often tricky because of its anatomical complexity, and special and customized strategies should be devised. This review discusses the endodontic implications of this anomaly and the current treatment recommendations based on anatomic, pathologic, and technologic considerations.

Management of Pulp Canal Obliteration-Systematic Review of Case Reports

Background and Objectives: This systematic review aimed to assess the literature focusing on the clinical management of traumatized teeth with Pulp Canal Obliteration (PCO) and propose an updated clinical decision-making algorithm. The present review follows the PRISMA guidelines and was registered on PROSPERO database (CRD42020200656). Materials and Methods: An electronic search strategy was performed in Pubmed, EBSCOhost and LILACS from inception to March 2021. Only anterior permanent teeth with PCO due to dental trauma were included. Regarding clinical approaches, only teeth managed with a “watchful waiting” approach, tooth bleaching or root canal treatment (RCT) were included. Quality assessment was performed using the JBI Critical Appraisal Tool for Case Reports. Results: Twenty case reports were selected, resulting in a total of 27 patients. The number of traumatized teeth diagnosed with PCO was 33. The “watchful waiting” approach was the most implemented clinical strategy. Discolored non-symptomatic PCO teeth were mostly managed with external bleaching. The prevalence of pulp necrosis (PN) was 36.4%. For teeth diagnosed with PN, non-surgical RCT was performed in 10 teeth and surgical RCT in one tooth. Guided endodontic technique was performed in six of those teeth. Conclusions: For discolored non-symptomatic PCO teeth, external bleaching is advocated and the RCT approach should not be implemented as a preventive intervention strategy. Symptomatic PCO teeth should follow regular endodontic treatment pathways. Clinical approach of teeth with PCO should follow a decision-making algorithm incorporating clinical and radiographic signs and patient-reported symptoms.

A Comparative Analysis of the Piezoelectric Ultrasonic Appliance and Trephine Bur for Apical Location: An In Vitro Study

To compare and contrast the accuracy of piezoelectric ultrasonic insert (PUI) and trephine bur (TB) osteotomy site preparation techniques for apical location. (1) Material and methods: A total of 138 osteotomy site preparations were randomly distributed into one of two study groups. Group A: TB technique (n = 69) and B: PUI technique (n = 69). A preoperative cone-beam computed tomography scan and an intraoral scan were performed and uploaded to implant-planning software to plan the virtual osteotomy site preparations for apical location. Subsequently, the osteotomy site preparations were performed in the experimental models with both osteotomy site preparation techniques and a postoperative CBCT scan was performed and uploaded into the implant-planning software and matched with the virtually planned osteotomy site preparations to measure the deviation angle and horizontal deviation as captured at the coronal entry point and apical end-point between osteotomy site preparations using Student’s t-test statistical analysis. (2) Results: The paired t-test found statistically significant differences at the coronal entry-point deviations (p = 0.0104) and apical end-point deviations (p = 0.0104) between the TB and PUI study groups; however, no statistically significant differences were found in the angular deviations (p = 0.309) between the trephine bur and piezoelectric ultrasonic insert study groups. (3) Conclusions: The results showed that the TB is more accurate than the PUI for apical location.

Micro-CT assessment of radicular pulp calcifications in extracted maxillary first molar teeth

OBJECTIVES

The present study aimed to evaluate the frequency, position, and length of radicular pulp calcifications in three-rooted maxillary first molars using micro-computed tomography.

MATERIALS AND METHODS

Two hundred three-rooted maxillary first molars were scanned at a pixel size of 10 µm and reconstructed using similar parameters. Three-dimensional models of the mesiobuccal (MB1, MB2, MB3), distobuccal (DB), and palatal (P) canals were qualitatively evaluated for discontinuity in the canal path. Transaxial and sagittal cross-sectional images of the roots were further screened, and the complete obliteration of the canal lumen by pulp calcification was identified when the canal had similar radiodensity to the surrounding dentine. Then, the number, position, and length of the calcifications were recorded for each root. Intra-observer agreement was performed using Cohen's kappa test, while one-way ANOVA and Duncan tests compared the lengths of calcifications among the canals, with α = 5%.

RESULTS

Intra-observer agreement was perfect for identification of pulp calcifications (ĸ = 1.0; p = 0.000). MB2 and MB3 canals accounted for the highest percentage frequency of calcifications distributed throughout the canal path. In the MB1, DB, and P canals, they occurred mainly at the apical third. Lengths of calcifications were greater in the MB3 (0.89 ± 0.81 mm) and MB2 (0.82 ± 0.93 mm) canals than in the MB1 (0.39 ± 0.32 mm), DB (0.34 ± 0.22 mm), and P (0.28 ± 0.22 mm) canals (p < 0.05).

CONCLUSION

MB2 and MB3 canals accounted for the highest frequency and length of radicular pulp calcifications. In the MB1, DB, and P canals, calcifications occurred mostly at the apical third, while in the MB2 and MB3, most of calcifications were observed at the orifice level and along the canal path.

CLINICAL RELEVANCE

In maxillary first molars, radicular pulp calcifications are mainly located at the apical third of the MB1, DB, and P canals, while in the MB2 and MB3 canals, most of them are at the orifice level or along the canal path.

Real-Time Guided Endodontics with a Miniaturized Dynamic Navigation System Versus Conventional Freehand Endodontic Access Cavity Preparation: Substance Loss and Procedure Time

INTRODUCTION

This study aimed to evaluate substance loss and the time required for access cavity preparation (ACP) using the conventional freehand method (CONV) versus a miniaturized dynamic navigation system of real-time guided endodontics (RTGE) in an in vitro model using 3-dimensional-printed teeth.

METHODS

Nine human anterior maxillary teeth were selected and micro-computed tomographic scanned. Root canals were virtually reduced to 2 mm below the cementoenamel junction. The teeth were digitally duplicated and mirrored to yield 6 different models with 6 single-rooted teeth each. The models were 3-dimensionally printed using radiopaque resin and consecutively mounted on a dental mannequin for ACP. Two operators with 12 and 2 years of clinical experience, respectively, received 6 models (36 teeth) each and performed ACP on half of the models using RTGE (after digital planning) and CONV on the other half 2 weeks later. The time was recorded. Postoperative substance loss was measured by cone-beam computed tomographic imaging. The differences in time and substance loss between the methods and operators were evaluated by the t test.

RESULTS

Overall, substance loss was significantly lower with RTGE than CONV (mean = 10.5 mm³ vs 29.7 mm³), but both procedures took a similar time per tooth (mean = 195 vs 193 seconds). Operator 1 (more experienced) achieved significantly less substance loss than operator 2 with CONV (mean = 19.9 vs 39.4 mm³) but not with RTGE (mean = 10.3 vs 10.6 mm³).

CONCLUSIONS

RTGE is a practicable, substance-sparing method performed in comparable time as CONV. Moreover, RTGE seems to be independent of operator experience.

Accuracy and Efficiency of 3-dimensional Dynamic Navigation System for Removal of Fiber Post from Root Canal-Treated Teeth

INTRODUCTION

The purpose of this study was to investigate the accuracy and efficiency of the 3-dimensional dynamic navigation system (DNS) compared with the freehand technique (FH) when removing fiber posts from root canal-treated teeth.

METHODS

Twenty-six maxillary teeth were included. Teeth were root canal treated and restored with Parapost Taper Lux (Coltene/Whaledent, Altstätten, Switzerland) luted with RelyX Unicem (3M ESPE, St Paul, MN). A core buildup was then performed using Paracore (Coltene/Whaledent). Teeth were mounted in tissue-denuded cadaver maxillae. Teeth were divided into 2 groups: the DNS group (n = 13) and the FH group (n = 13). Cone-beam computed tomographic scans were taken pre- and postoperatively. The drilling path and depth were planned virtually using X-guide software (X-Nav Technologies, Lansdale, PA) in both groups. For the DNS group, drilling was guided with X-Nav software and the FH group under a dental operating microscope. Global coronal and apical deviations, angular deflection, operation time, and the number of mishaps were compared between the groups to determine the accuracy and efficiency. The 3-dimensional volume (mm³) of all teeth was calculated before and after post removal using the Mimics Innovation Suite (Materialise NV, Leuven, Belgium). The Shapiro-Wilk, 1-way analysis of variance, and Fisher exact tests were used (P < .05).

RESULTS

The DNS group showed significantly less global coronal and apical deviations and angular deflection than the FH group (P < .05). DNS required less operation time than FH. Moreover, the DNS technique had significantly less volumetric loss of tooth structure than the FH technique (P < .05).

CONCLUSIONS

The DNS was more accurate and efficient in removing fiber posts from root canal-treated teeth than the FH technique.

Dynamic navigation: a laboratory study on the accuracy and potential use of guided root canal treatment

AIM

To evaluate 3D accuracy and outcome of a dynamic navigation method for guided root canal treatment of severe pulp canal obliteration (PCO) in 3D printed jaws.

METHODOLOGY

Three operators with different levels of experience in Endodontics performed navigated access cavities, using the Navident system (ClaroNav), in two sets (maxillary and mandibular) of 3D-printed jaw models with teeth presenting severe PCO. Models were mounted on a phantom to mimic a real clinical situation. After treatment, a postoperative high resolution Cone-Beam Computer Tomography (CBCT) scan (NewTom) was taken for each model and registered to the preoperative model. All access cavities were then segmented using 3-Matic Medical software 15.0 (Materialise). Length and volume of each access cavity were measured, and a comparison was done by measuring the distance deviation in mm at the coronal entry point, apical point, vertical deviation, total deviation and angular deviation of the access cavity in comparison with the virtual planning. Additionally, all access cavities were scouted with a size 10 K-file and inspected on the CBCT to confirm that the canal was located. Descriptive statistics for each parameter were performed. Normality of the data was assessed; data were transformed if needed to make it normally distributed. One-way analysis of variance (anova) was applied to assess differences between parameters for tooth type, jaw, and operators and corrected for simultaneous hypothesis testing according to Tukey. Significance level was set at .05.

RESULTS

After training with the system (28 cavities per operator), a total of 132 teeth and 168 access cavities (56 per operator) were prepared. All operators located a total of 156 canals, obtaining an overall success of 93% without a difference between operator experience (p > .05). The mean deviation at the apical point was 0.63 mm (SD 0.35) and was significantly lower in anterior teeth in comparison with molars (p < .05). The mean angular deviation from the planning was 2.81° (SD 1.53).

CONCLUSION

Dynamic navigation was an accurate approach for root canal treatment in teeth with severely calcified canals. However, the technique has a learning curve and requires extensive training prior to its use clinically.

Accuracy and efficiency of guided root-end resection using a dynamic navigation system: a human cadaver study

AIM

To determine and compare the accuracy and efficiency of a dynamic navigation system (DNS) with a freehand (FH) technique when conducting root-end resection in a human cadaver model.

METHODOLOGY

Forty roots in cadaver heads were included and divided into two groups: DNS (n = 20) and FH (n = 20). Cone beam computed tomography (CBCT) scans of all teeth were taken. The drilling path and depth were planned virtually to using the X-guide software (X-Nav Technologies, Lansdale, PA, USA). Osteotomy and root-end resection were done under navigation in the DNS group, and freehand under the dental operating microscope in the FH group. Post-operative CBCTs were taken. Linear deviations, angular deflection, time of operation and number of mishaps were compared with determine the accuracy and efficiency. Shapiro-Wilk, one-way ANOVA and Fisher exact tests were used (P < 0.05).

RESULTS

Linear deviations, angular deflection and operation time were significantly less in the DNS group (P < 0.05). The number of mishaps was not different between the two groups (P > 0.05). Subgroup analyses revealed that the distance of >5 mm from buccal cortical plate was significantly associated with lower accuracy, increased operation time and greater incidence of mishaps in the FH group (P < 0.05), but not in the DNS group.

CONCLUSIONS

The dynamic navigation system was more accurate and more efficient in root-end resection in a cadaver model than the freehand technique. The distance of the roots from the buccal cortical plate had a significant negative impact on the accuracy and efficacy of the root-end resection procedure when using the freehand technique. The dynamic navigation system has the potential to be a safe and reliable technological addition to endodontic microsurgery.

Endodontic Retreatment Using Dynamic Navigation: A Case Report

INTRODUCTION

Dynamic navigation systems are used in dental implantology to optimize the accuracy of dental implant placement.

METHODS

A 30-year-old man was seen at the endodontic clinic of the Universidad Autónoma de Yucatán for pain in the left maxillary lateral incisor. A previously treated tooth with symptomatic apical periodontitis was diagnosed. The patient accepted treatment, and after signing an informed consent form, minimally invasive coronal access was performed through a zirconia crown. Then a post removal was performed with an ultrasonic tip to 2 mm before the apical gutta-percha limit, and the removal of material was completed manually with a K-file.

RESULTS

This case report demonstrates the use of dynamic navigation to remove a post from under a zirconia crown for the retreatment of a failing root canal procedure. The removal of fiber posts from endodontically treated teeth can present a unique challenge for clinicians. Numerous techniques and instrument kits are recommended for the removal of fiber posts, but the risk of excessive root structure damage is a major concern because the ability to differentiate the color difference between peripheral dentin and a bonded fiber post can complicate the accuracy of the removal.

CONCLUSIONS

The dynamic navigation system enabled minimally invasive removal of the fiber post with a high degree of accuracy, thus ensuring that there was no unnecessary removal of root structure. Dynamic navigation using real-time monitoring could reduce the attendant risk of iatrogenic errors in complex treatment cases.

Effect of Computer-Aided Navigation Techniques on the Accuracy of Endodontic Access Cavities: A Systematic Review and Meta-Analysis

The present systematic review and meta-analysis aims to determine the effect of computer-aided navigation techniques on the accuracy of endodontic access cavities.

MATERIALS AND METHODS

A systematic literature review and meta-analysis of clinical studies, based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations, was performed that evaluated the root canal location rate of computer-aided navigation techniques applied to endodontic access cavities. Four different databases were used to consult the literature: PubMed-Medline, Scopus, Cochrane, and Web of Science. After discarding duplicate articles and applying inclusion criteria, 14 articles were selected for qualitative analysis and 13 for quantitative analysis.

RESULTS

the root canal location success rate started at 98.1% (CI: 95.7-100%) of the cases performed through a computer-aided navigation technique. The prediction interval ranged from 93.3% to 100%. The meta-analysis did not detect heterogeneity between the combined studies (Q-test = 17.3; p = 0.185; I² = 25%). No statistically significant differences were found between computer-aided static navigation techniques (success rate: 98.5%) and computer-aided dynamic navigation techniques (success rate: 94.5%) (Q test = 0.57; p = 0.451), nor between in vitro studies (success rate: 96.2%) and in vivo studies (success rate: 100%) (Q test = 2.53; p-value = 0.112). An odds success ratio of 13.1 (CI: 95%; 3.48, 49.1) encourages the use of computer-aided navigation techniques over conventional endodontic access cavity procedures.

CONCLUSIONS

the endodontic access cavities created using static and dynamic computer-aided navigation techniques are highly accurate in locating the root canal system.

Chamberless Endodontic Access for Treatment of Calcified Anterior Central Incisors

INTRODUCTION

Modern techniques for treating maxillary anterior central incisors with calcified canals emphasize maintaining coronal dentin with small crown access. Alternatively, traditional retrograde surgical procedures are focused on creating an apical seal predominately limited to the remaining resected apical one third of the root canal space. A treatment option for calcified anterior teeth, with avoidance of traditional orthograde access, is presented. Chamberless endodontic access (CEA) to the canal is chosen in this case, leveraging a previous surgical treatment and osseous defect to create straight line canal access.

METHODS

A tooth presenting with a chronic apical abscess and an apparent previous apical surgery was instrumented and obturated using a CEA avoiding the traditional orthograde approach to the root canal system. Straight line approach was achieved retrograde and canal instrumentation was performed using ultrasonic activated U-files. Canal obturation was accomplished with warm vertical condensation technique followed by placement of an apical retroseal.

RESULTS

A successful 52-month outcome demonstrated the viability of CEA facilitating retrograde instrumentation and obturation.

CONCLUSIONS

Use of CEA simultaneously protected the clinical crown and provided a successful clinical outcome. A viable option for treatment of an anterior calcified canal and abscess due to dental trauma, CEA mitigates many of the risks associated with the treatment of calcified root anatomy.