Guided root canal preparation using cone beam computed tomography and optical surface scans – an observational study of pulp space obliteration and drill path depth in 50 patients

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.

Removal of fiber posts using conventional versus guided endodontics: a comparative study of dentin loss and complications

OBJECTIVES

To compare the efficacy of fiber post removal using conventional (CONV) versus guided endodontics (GE) in terms of dentin loss, residual resin material, procedural errors, and working time in vitro.

MATERIAL AND METHODS

Ninety human central incisors were root-filled and scanned by micro-computed tomography (CT), then restored with fiber posts and composite. Twenty-four sets of teeth with up to four human maxillary central incisors were fabricated and divided into three groups: conventional post removal by a general dentist (CG) or endodontology specialist (CS) and guided endodontics (GE) by a general dentist, yielding 30 teeth per operator and group. After treatment, the prepared access cavities were volumetrically assessed by micro-CT. Statistical significance was evaluated by one-way analysis of variance followed by post hoc comparisons with Tukey's HSD test and Pearson's chi-squared test for independence.

RESULTS

Both CONV and GE resulted in dentin loss and residual resin material. CS resulted in more dentin loss and less residual resin material than CG and GE (p < .05). All groups had some deviations from the original root canal but no perforations. The shortest working time was observed in the GE group.

CONCLUSIONS

Compared to the conventional freehand technique, GE resulted in significantly less radicular dentin loss, a few deviations but no perforations.

CLINICAL RELEVANCE

Guided endodontics can improve the speed and safety of fiber post removal without root perforation.

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.

Three-dimensional accuracy of endodontic access preparations using novel nonrestrictive static guides: A laboratory study

This study compared the accuracy of traditional endodontic access to conservative access cavities prepared with or without novel nonrestrictive endodontic access guides by operators with different levels of clinical experience without visual aids, using a three-dimensional volumetric accuracy analysis method. The accuracy of the preparations was analysed using a novel 3D volumetric analysis by calculating the intersection and volume of the actual cavities to the planned model cavities. The experienced operator significantly outperformed the inexperienced operator in the free hand groups, while accuracy of conservative access cavities prepared using the novel guides were comparable and significantly higher than the other groups (p < 0.05). The results demonstrated clinical experience enhanced endodontic preparations accuracy and that nonrestrictive guides achieve accurate conservative access cavities which are independent of the operator skill level. Additionally, the three-dimensional volumetric analysis is a consistent and objective method to judge the accuracy of guided endodontic techniques.

Guided endodontics versus conventional access cavity preparation: an ex vivo comparative study of substance loss

BACKGROUND

To compare the outcomes of conventional access cavity preparation (CONV) versus guided endodontics (GE) for access cavity preparation in anterior teeth with pulp canal calcification (PCC) regarding root canal detection, substance loss, procedural time, and need for additional radiographs.

METHODS

Extracted, sound human teeth with PCC (n = 108) were matched in pairs, divided into two groups and used to produce 18 models. An independent endodontist and a general dentist performed access cavity preparation under simulated clinical conditions on nine models each (54 teeth). The endodontist used the conventional technique and the general dentist GE. Time needed to access the root canals and the number of additional radiographs were recorded. Pre- and postoperative cone-beam computed tomography scans were obtained to measure substance loss. Statistical significance was tested by examining the overlap of 95% confidence intervals (CIs) between the groups.

RESULTS

All root canals were successfully accessed by both methods. There were no significant differences in substance loss (CI: CONV 15.9-29.6 mm3 vs. GE 17.6-27.5mm3) or procedural time (CI: CONV 163.3-248.5 s vs. GE 231.9-326.8 s). However, 31 additional radiographs were required for GE compared to none for CONV.

CONCLUSIONS

For access cavity preparation in teeth with PCC, both CONV by a specialist and GE by a general dentist produce good results in terms of substance loss and time requirements.

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.

Guided endodontics of calcified canals: The drilling path of rotary systems and intracanal dentin wear

This study evaluated the drilling path (mm) and the dentin wear (mm3 ) of two instruments used during guided endodontic access. Twenty mandibular incisors with calcified canals were selected using cone-beam computed tomography (CBCT) and fixed in articulated models. Preoperative CBCT scans were performed in combination with intraoral scanning, and the images were reconstructed in the Blue Sky Bio software for access planning and printing the guides. The access cavity was drilled with 1.0-mm-diameter bur (DSP) and 0.8-mm-diameter bur (Munce). Postoperative CBCT was performed, and the images obtained preoperative and postoperative were superimposed for the analyses. Data were analysed by a t-test and linear regression (α = 0.05). No difference was found in the drilling path (p = 0.422). However, the Munce bur had higher dentin wear than the DSP bur (p = 0.011). A positive linear correlation (R2  = 0.859) was found between the factors.

Influence of Calcified Canals Localization on the Accuracy of Guided Endodontic Therapy: A Case Series Study

This study aimed to evaluate the precision of the guided endodontic technique applied to calcified canals in anterior teeth in relation to demographic and dental variables. The present observational study was conducted during the period 2020-2021. The patients were consecutive referrals at the Department of Endodontics and Conservative Dentistry of the University Hospital of Siena. The guided endodontics protocol was applied using 0.75 mm diameter burs for the lower teeth and 0.90 mm for the upper teeth. The inclusion criteria were as follows: (i) teeth with pulp canal obliteration (PCO) associated with a periapical lesion (periapical index (PAI) ≥ 2); (ii) teeth with PCO that require the placement of a root canal post for the execution of a prosthetic treatment; (iii) teeth in which surgical treatment was not justified. Socio-demographic characteristics of the patients were recorded and related to the drill path accuracy through the guide in the calcified endodontic canal, evaluated through a radiographic analysis, and classified as optimal (in the center of the root canal) and acceptable (deviated peripherally/tangentially). A logistic regression model was built to predict the factors that influence the poor precision of the technique. Seventeen patients (mean age 48 years) with eighteen calcified single-rooted teeth were enrolled. All teeth were associated with periapical lesions with PAI scores from 2 to 5 (mean PAI: 3.055). From the model, it is evident that the presence of a calcification affecting the apical area of the root increases the probability of being off-center with the bur by about 15 times. In addition, a previous attempt at endodontic treatment and the position in the lower arch increases the probability of non-centrality of the drill, although in a non-statistically significant way. In any of the analyzed cases, the guided endodontic technique applied to PCO did not determine the presence of iatrogenic errors, such as perforations. However, the apical localization of the obliteration increases the probability of being off-center with the drill during the instrumentation phase by about 15 times.

Ex-vivo and in-vivo validation of a novel measuring protocol for guided endodontics

OBJECTIVES

To (1) validate the use of a post-operative intraoral scan (IOS) versus Cone Beam Computed Tomography (CBCT), gold standard, on its ability to measure the accuracy of guided endodontics, and (2) present clinical data on the accuracy of guided endodontics.

METHODS

Four models, including 10 extracted teeth each, were created. Forty guided access cavities were planned on dentin to simulate pulp canal obliteration (PCO). Two operators performed guided access cavities. A post-operative CBCT and IOS were acquired. The deviation coronally, apically, and angular deviation was measured with CBCT and IOS. Clinical accuracy was measured using an IOS acquired immediately after drilling the access cavity with the aid of a guide. Data analysis was performed using multiway Anova and corrected for simultaneous hypothesis testing according to Tukey. P ≤ 0.05 was considered statistically significant. Descriptive statistics on the clinical accuracy of guided endodontics were performed.

RESULTS

Thirty-eight cavities were assessed with a mean length of 13.8 mm. No statistical difference between operators and methods was found for all parameters (P > 0.05). Thirty-three patients were treated with guided endodontics and measured using an IOS. Results show an average coronal, apical, and angular deviation of 0.2 mm, 0.45 mm, and 1.91^° respectively. The average length of the access cavities was 12.5 mm.

CONCLUSIONS

An IOS can be used to measure the accuracy of guided endodontics. Clinical data showed high accuracy of guided endodontics with a mean apical deviation smaller than 0.5 mm and a mean angular deviation of less than 2^°.

CLINICAL SIGNIFICANCE

The use of an IOS does not involve additional radiation exposure. A safety margin of at least 1 mm around the planned trajectory should be respected when planning the case to minimize the possibility of root perforation.

Tooth substance loss after incisal endodontic access and novel single-tooth template-guided endodontic access in three-dimensional printed resin incisors with simulated pulp canal calcification: A comparative in vitro study

Context Background

Guided endodontics has various applications, one of which is for calcified canal negotiation. Recently, a new single-tooth template has been fabricated to overcome the drawbacks of bulky guides, which are difficult to use with rubber dam isolation.

Aim

This study aimed to assess the efficacy of the novel single-tooth template for negotiation of pulp canal calcification (PCC) in three-dimensional (3D)-printed resin incisors by comparing substance loss and time taken between incisal endodontic access (IEA) and single-tooth template-guided endodontic access (SGEA).

Methods

Forty-two resin incisor teeth having patent canal in the apical third were used (N = 21/group). They were subcategorized based on operator's experience into senior endodontist (SE), postgraduate (PG), and undergraduate (UG) (n = 7/operator). Canals were negotiated conventionally for IEA and using the single-tooth template for SGEA. Substance loss was calculated from the volume difference between pre- and postoperative cone-beam computed tomography scans. The time taken was also recorded.

Statistical Analysis Used

Statistical analysis was performed using unpaired t-test and one-way analysis of variance test.

Results

Canals were successfully negotiated in 100% and 95% of teeth in the SGEA and IEA groups, respectively. Overall substance loss and time taken were significantly lesser for SGEA for all operators (P < 0.001). In the IEA group, post hoc test showed statistical significance between SE and UG for substance loss (P < 0.05) and SE-UG and PG-UG for time taken (P < 0.05). No significant difference among operators was noted for both parameters in SGEA.

Conclusions

SGEA resulted in significantly lesser substance loss and time taken for canal negotiation in 3D-printed resin incisors with simulated PCC. This was independent of the experience levels of the operator.

In vitro study on the accuracy of sleeveless guided endodontics and treatment of a complex upper lateral incisor

PURPOSE

The present study aims to assess the accuracy of sleeveless guided endodontics for root canal treatment of severe pulp canal obliteration (PCO) in 3D printed jaws. Additionally, the treatment of a complex lateral incisor is presented to illustrate the use of sleeveless guides in a clinical situation.

METHODS

Two cone-beam computed tomography (CBCT) volumes of an upper and lower jaw were selected to design 3D printed models with PCO. Virtual planning of the access cavities was performed from right to left second premolar. Then, the models were mounted into a phantom head to simulate an actual patient. Two operators with different levels of experience in endodontics performed guided access cavities. The handpiece was guided by guiding rails placed against each other on the sides of the tooth. A post-operative CBCT scan was taken for analysis.

RESULTS

Eighty-eight guided access cavities (44 per operator) were drilled on eight 3D printed models. The mean length of the access cavities was 15.3 mm, with a mean coronal and apical deviation of 0.5 mm and 0.7 mm respectively. The mean angular deviation was 1.5^°. No statistically significant difference was found between operators for the three measured parameters.

CONCLUSIONS

This study demonstrates, within its limitations, that sleveless guides represent an accurate method for guided endodontic treatment. No statistically significant difference between operators was found when using the guide.

CLINICAL SIGNIFICANCE

This method offers a valuable alternative to conventional endodontic guides with similar accuracy results.

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.

Effectiveness of guided endodontics in locating calcified root canals: a systematic review

OBJECTIVES

The aim of this study is to answer the question: "Is guided endodontics an effective technique for locating calcified canals?".

METHODS

A systematic search was carried out by two independent authors in PubMed, Web of Science, Scopus, and Scielo databases. According to the PIOS criteria, observational studies, ex vivo studies, clinical case reports, and case series were included. The quality of evidence of observational studies, case reports, and case series were assessed using the respective Joanna Briggs Institute critical appraisal tool, and a previous personalized tool was used to assess the quality of the ex vivo studies.

RESULTS

Forty-five studies were included. Of them, 21 were clinical case reports, 11 case series, 12 ex vivo studies, and 1 cohort study. Of the 45 studies analyzed, 43 reported that guided endodontics is an effective and precise technique to access the permeable portion of calcified canals. Only 2 studies report accidents or failures related to the use of endodontic guides.

CONCLUSIONS

Guided endodontics allows conservative access, minimizes accidents, and is effective in locating calcified canals; however, it is a technique that still presents limitations.

CLINICAL RELEVANCE

Guided endodontics has been proposed as a simple and effective technique for the treatment of calcified canals. The expansion of this technique requires knowing its benefits and limitations to ensure success and avoid accidents.

The accuracy of using guided endodontics in access cavity preparation and the temperature changes of root surface: An in vitro study

Background

Guided endodontics is a successful technique that has been gradually applied to endodontic therapy in recent years without being affected by the operator’s experience. However, the guided bur produces excessive heat during continuous rotation and friction with root canal walls, it is not clear whether the degree of temperature increase may lead to the periodontal ligament and alveolar bone damage.

Methods

A total of 58 teeth were used, of which 40 teeth were not grouped, all used to evaluate the accuracy. 40 single-rooted premolars were scanned using CBCT and an intra-oral scanner, and 3D-printed guided plates were made with the pre-designed access. A custom-made guided bur was used to prepare the access cavities. The postoperative CBCT data and pre-designed pathways were matched to evaluate the deviation between the planned and virtual paths. The other 18 teeth were randomly divided into three groups (ET20 and ProTaper F3 as the control group, guided endodontics as the test group), with 6 teeth in each group. The temperature changes on the root surfaces were inspected with a thermocouple thermometer.

Results

The average deviation on the tip and the base of the bur was 0.30 mm and 0.28 mm (mesial/distal), and 0.28 mm and 0.25 mm (buccal/lingual). The average angle deviation was 3.62°. The mean root surface temperature rise of the guided endodontics group was the lowest (5.07 °C) (P < 0.05).

Conclusions

The access cavity preparation performed with guided endodontics has feasible accuracy and low-temperature rise on the root surfaces. Due to the limitations of the study, whether it has high reliability and safety in clinical applications needs to be further studied in vivo.

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 as a Personalized Tool for Complicated Clinical Cases

The aim of this paper is to present a technique to individualize root canal localization in teeth with calcified root canals using a digitally planned, 3D-printed endodontic guide. Root canal calcification is characterized by the apposition of tertiary dentin along the canal wall. The endodontic treatment of teeth with calcified canals is often challenging. However, digital dentistry meets these challenges. Merging CBCT images with an intraoral scan allows a clinician to prepare an endodontic guide. This article describes the clinical and digital workflow of the guided endodontic access approach in teeth with difficulties in terms of root canal localization due to post-traumatic pulp canal obliteration (PCO) and canal calcification in elderly patients. The path of entry into the root canal system was planned using cone-beam computed tomography (CBCT). The template was printed on a 3D printer using transparent resin. During root canal treatment (RCT), the endodontic tool was inserted through the sleeve until the desired location was reached. The use of an endodontic guide allowed for minimally invasive RCT, avoiding the excessive loss of tooth structures. Navigated endodontics enables clinicians to perform RCT in a more predictable manner and allows clinicians to avoid iatrogenic complications, which improves the treatment prognosis.

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.

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.

Traditional and minimally invasive access cavities in endodontics: a literature review

The aim of this review was to evaluate the effects of different access cavity designs on endodontic treatment and tooth prognosis. Two independent reviewers conducted an unrestricted search of the relevant literature contained in the following electronic databases: PubMed, Science Direct, Scopus, Web of Science, and OpenGrey. The electronic search was supplemented by a manual search during the same time period. The reference lists of the articles that advanced to second-round screening were hand-searched to identify additional potential articles. Experts were also contacted in an effort to learn about possible unpublished or ongoing studies. The benefits of minimally invasive access (MIA) cavities are not yet fully supported by research data. There is no evidence that this approach can replace the traditional approach of straight-line access cavities. Guided endodontics is a new method for teeth with pulp canal calcification and apical infection, but there have been no cost-benefit investigations or time studies to verify these personal opinions. Although the purpose of MIA cavities is to reflect clinicians' interest in retaining a greater amount of the dental substance, traditional cavities are the safer method for effective instrument operation and the prevention of iatrogenic complications.

The effects of endodontic access cavity design on dentine removal and effectiveness of canal instrumentation in maxillary molars

AIM

To evaluate in a laboratory setting, the impact of three designs of endodontic access cavities on dentine removal and effectiveness of canal instrumentation in extracted maxillary first molars using micro-computed tomography (micro-CT).

METHODOLOGY

A total of 30 extracted intact maxillary first molars were selected and scanned by micro-CT with a voxel size of 24 µm and randomly distributed into three groups: the traditional endodontic cavity (TEC) group, the conservative endodontic cavity (CEC) group and the guided endodontic cavity (GEC) group. The pulp chambers of teeth in the groups were accessed accordingly. After root canal preparation, the teeth were rescanned. The volume of dentine removed after canal preparation, the noninstrumented canal areas, canal transportation and centring ratio were analysed. Data were analysed statistically using one-way analysis of variance. Tukey's post hoc test was used for multiple comparisons. The significance level was set at p < .05.

RESULTS

The total volume of dentine removed was significantly greater in the TEC group after root canal preparation (p < .05). No significant differences in the volume of dentine removed occurred between the CEC and GEC groups (p > .05). The volume of dentine removed in the crown, pericervical dentine and coronal third of the canal was significantly lower in CEC and GEC groups when compared to that in the TEC group (p < .05), no difference was observed in the middle third of the canal and apical third of the canal amongst the three groups (p > .05). There was no significant difference in noninstrumented canal area, canal transportation and centring ratio amongst the TEC, CEC and GEC groups (p > .05).

CONCLUSIONS

In extracted maxillary molars tested in a laboratory setting, CEC and GEC preserved more tooth tissue in the crown, pericervical dentine and coronal third of the canal compared with TEC after root canal preparation. The design of the endodontic access cavity did not impact on the effectiveness of canal instrumentation in terms of noninstrumented canal area, canal transportation and centring ratio.

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.

European Society of Endodontology position statement: endodontic management of traumatized permanent teeth

This position statement represents a consensus of an expert committee convened by the European Society of Endodontology (ESE) on the endodontic management of traumatized permanent teeth. A recent comprehensive review with detailed background information provides the basis for this position statement (Krastl et al. 2021, International Endodontic Journal, https://doi.org/10.1111/iej.13508). The statement is based on current scientific evidence as well as the expertise of the committee. Complementing the recently revised guidelines of the International Association of Dental Traumatology, this position statement aims to provide clinical guidance for the choice of the appropriate endodontic approach for traumatized permanent teeth. Given the dynamic nature of research in this area, this position statement will be updated at appropriate intervals.

Endodontic management of traumatized permanent teeth: a comprehensive review

The pulp plays a key role in the treatment of traumatic dental injuries (TDIs) and is strongly associated with the outcome, particularly in severe cases. A correct pulp diagnosis is essential as it forms the basis for developing the appropriate management strategy. However, many TDIs are complex, and their treatment requires a profound knowledge of the physiological and pathological responses of the affected tissues. This comprehensive review will look at the dentine-pulp complex and its interaction with the surrounding tissues following TDIs. The literature up to 2020 was reviewed based on several searches on PubMed and the Cochrane Library using relevant terms. In addition to the recently revised guidelines of the International Association of Dental Traumatology, this article aims to provide background information with a focus on endodontic aspects and to gather evidence on which a clinician can make decisions on the choice of the appropriate endodontic approach for traumatized permanent teeth.

Suitability of Magnetic Resonance Imaging for Guided Endodontics: Proof of Principle

INTRODUCTION

This proof-of-principle study aimed to demonstrate that magnetic resonance imaging (MRI) is sufficiently accurate for the detection of root canals using guided endodontics.

METHODS

One hundred extracted human teeth (anterior and premolar) were mounted onto 5 mandibular and 5 maxillary models, fitted with splints designed to accommodate a thin layer of aqueous gel for indirect imaging, and scanned by MRI. After MRI and intraoral scans were aligned using planning software, access cavities were planned virtually, and templates were manufactured with computer-aided design/computer-aided manufacturing, the access cavities were prepared. Cone-beam computed tomographic scans were performed and matched with the virtual preoperative planning data to determine the accuracy of access cavity preparation in terms of deviation between planned and prepared cavities in the mesiodistal and buccolingual dimensions and angle. Descriptive statistical analysis was performed, and the mean values were compared using the t test.

RESULTS

Ninety-one of 100 root canals were successfully scouted after MRI-guided access cavity preparation. The mean angle deviation was 1.82°. The mean deviation ranged from 0.21-0.31 mm at the base of the bur and from 0.28-0.44 mm at the tip of the bur. Preparation in the buccolingual dimension was significantly more precise in mandibular compared with maxillary teeth, and accuracy in the mesiodistal dimension was more precise in anterior teeth compared with premolars.

CONCLUSIONS

This in vitro study demonstrated the suitability of MRI for guided endodontic access cavity preparation.

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.

Guided endodontics: The impact of new technologies on complex case solution

Discuss the impact of new diagnostic and planning technologies on the resolution of a clinical case of an upper central incisor with lateral perforation, root canal calcification and apical periodontitis. A 44-year-old woman sought treatment because of a colour change in an anterior tooth. The tooth had already been endodontically accessed, and she reported that two different clinicians had failed to locate the root canal. A Cone Beam Computed Tomography scan showed excessive wear and root perforation in the middle third, as well as pulp canal obliteration in the apical third. The perforation was treated using a biomaterial, and the root canal was located using guided endodontics. This treatment protocol was used to access, prepare, medicate with calcium hydroxide for 21 days and fill the root canal. Treatment results were satisfactory at 6-month follow-up.

Guided Endodontics for Managing Severely Calcified Canals

Endodontic treatment of teeth with pulp canal obliteration presents a challenge given the high likelihood of procedural errors and complications during treatment. These drawbacks can be avoided by using a personalized 3-dimensional (3D) guide designed by overlaying a cone-beam computed tomographic scan with an intraoral scan of the patient. This 3D guide enables the clinician to obtain a straight access to the obliterated root canal.This article described guided endodontics in managing 7 severely obliterated teeth using both virtually designed 3D guides and a customized 1-mm-diameter cylindrical bur. This treatment approach was demonstrated to be safe and fast and can be considered as a predictable technique for the location of calcified canals, thus minimizing complications.

Minimization of Tooth Substance Removal in Normally Calcified Teeth Using Guided Endodontics: An In Vitro Pilot Study

INTRODUCTION

This study evaluated the success rate of and tooth substance removal required for computer-guided preparation of endodontic access cavities.

METHODS

Thirty acrylic typodont teeth with root canals (10 each of tooth numbers 11, 14, and 17) were randomly allocated to a study or control group (15 teeth per group). In the study group, teeth were fixed in acrylic resin and subsequently digitized using a laboratory scanner. A cone-beam computed tomographic scan was then taken. Access cavity preparations were planned virtually, and a template was 3-dimensionally printed. In the control group, access cavities were prepared using the conventional access technique. Tooth substance removal was assessed by weighing teeth before and after preparation. Volume loss was analyzed statistically by use of the Wilcoxon-Mann-Whitney test at a significance level of P < .05.

RESULTS

Using guided endodontics, 93.3% of root canals were located successfully compared with 100% of root canals using the conventional technique. In the control group, the mean tooth substance removal was 16.1 ± 3.7 mm³ for incisors, 44.2 ± 8.9 mm³ for premolars, and 99.3 ± 3.1 mm³ for molars. In the study group, significantly less tooth substance was removed; substance loss was 10.3 ± 1.1 mm³ for incisors, 29.3 ± 4.2 mm³ for premolars, and 51.8 ± 5.3 mm³ for molars.

CONCLUSIONS

The use of guided endodontics in normally calcified teeth enables the preservation of a significant amount of tooth substance. However, this advantage must be carefully balanced against a greater radiation burden and risk of perforation, higher costs, and more difficult debridement and visualization of the pulp chamber and root canals.

Guided endodontic treatment of multiple teeth with dentin dysplasia: a case report

Background

To report the outcome of guided endodontic treatment (GET) of a case of dentin dysplasia with pulp canal calcification (PCC) and apical periodontitis based on the use of a 3D-printed template designed by merging cone-beam computed tomography (CBCT) and surface scan data.

Case presentation

A 12-year old female with radicular dentin dysplasia type I (DD-1) presented for endodontic treatment. Radiography revealed PCC in all teeth and apical radiolucency in seven teeth (12, 15, 26, 31, 32, 36 and 46). Tooth 36 had the most acute symptoms and was thus treated first by conventional access cavity preparation and root canal detection. Despite meticulous technique, the distal and mesiolingual canals were perforated. The perforations were immediately repaired with mineral trioxide aggregate, and the decision was made to switch to guided endodontic treatment for the remaining 6 teeth. CBCT and intraoral surface scans were acquired and matched using coDiagnostix planning software (Dental Wings Inc.), the respective drill positions for root canal location were determined, and templates were virtually designed and 3D-printed. The template was positioned on the respective tooth, and a customized drill was used to penetrate the calcified part of the root canal and perform minimally invasive access cavity preparation up to the apical region. All root canals were rapidly and successfully located with the templates. At 1-year follow-up, clear signs of apical healing were present in all treated teeth.

Conclusions

In patients with dentin dysplasia, conventional endodontic therapy is challenging. GET considerably facilitates the root canal treatment of teeth affected by dentin dysplasia.

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.

Guided Endodontics: Use of a Sleeveless Guide System on an Upper Premolar with Pulp Canal Obliteration and Apical Periodontitis

Guided endodontics has been used for the treatment of anterior teeth with a successful outcome. This approach is not only limited to anterior teeth because it can also be used for the treatment of premolars and molars. However, in such cases, space may be a limitation because a long bur has to be used in addition to the guide being placed on top of the teeth. The aim of this case report was to present a novel guided endodontics technique using a sleeveless 3-dimensional-printed guide. This design can reduce vertical space, allowing an open view of the tooth and irrigation during drilling. A 46-year-old female patient consulted the endodontic department with intermittent pain around tooth #5. Tooth #5 presented pain upon percussion and responded negative to a cold test. The initial periapical radiograph revealed an apical radiolucency with pulp canal obliteration. Clinically, there was no sinus tract. The tooth was diagnosed with pulp necrosis and symptomatic apical periodontitis. Guided endodontic treatment was performed with a sleeveless 3-dimensional-printed guide and long neck carbide bur with a head diameter of 1 mm to drill a minimally invasive access cavity up to the root canal. A completely healed apical area of tooth #5 was visible after 1 year on periapical radiographs. This technique seems to be a promising alternative in comparison with the conventional guided endodontic guide design for the negotiation of pulp canal obliteration in cases in which vertical space is limited.

Adaptable fiberglass post after 3D guided endodontic treatment: Novel approaches in restorative dentistry

OBJECTIVE

The rehabilitation of extensively damaged teeth with great structural loss and calcified root canals represents a challenge for dentistry. Classically, this restorative procedure of endodontically treated teeth involves intraradicular post placement. Retentive function post that can closely adapt to the root canal without the excessive wear of intraradicular dentin has a fundamental importance to ensure the longevity of the restoration.

CLINICAL CONSIDERATIONS

This report presents a clinical case of 3D guided access to a severely calcified pulp canal followed by the cementation of a fiberglass post that is adaptable to the root canal and prosthetic rehabilitation with full ceramic crown.

CONCLUSIONS

3D guided access allowed conservative and safe root canal treatment. The adaptable fiberglass post meets the specific needs of the described case and has a simple technique and low cost.

CLINICAL SIGNIFICANCE

Guided endodontics is a minimally invasive approach for teeth with calcified root canals. The post used in this study meets the demands of teeth endodontically treated with conservative techniques. The professional should not need to adapt the anatomy of the root canal to the anatomical reality of the post. This one adapts itself to the shape of the canal.