Guided Access Cavity Preparation Using Cost-Effective 3D Printers

Application of personalized templates in minimally invasive management of coronal dens invaginatus: a report of two cases

BACKGROUND

Treating the coronal dens invaginatus (CDI) with pulp infection commonly involves the removal of invagination, which increases the risk of perforation and fracture, and compromises the tooth structure. Minimally invasive endodontic management of CDI is highly recommended. This report describes two cases of type II CDI with the application of personalized templates.

CASE PRESENTATION

Two cases of type II CDI, affecting the main root canal in a maxillary canine and a lateral incisor, were diagnosed. A guided endodontics (GE) approach was applied. Cone-beam computed tomography and intraoral scans were imported and aligned in a virtual planning software to design debridement routes and templates. The MICRO principle (which involves the aspects of Mechanical (M) debridement, Irrigation (I), Access cavities (C), Rectilinear routes (R), and Obstruction (O)) was proposed for designing optimal debridement routes for future applications. The templates were innovatively personalized and designed to preserve the tooth structure maximally while effectively debriding the root canal. Root canal treatment with supplementary disinfection was then performed. The follow-up of the two patients revealed favorable clinical and radiographic outcomes.

CONCLUSIONS

The GE approach could be a feasible method for preserving healthy dental structure while effectively debriding the root canal, thereby achieving successful and minimally invasive endodontic treatment for CDI.

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.

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.

Access Cavity Preparation and Localization of Root Canals Using Guides in 3D-Printed Teeth with Calcified Root Canals: An In Vitro CBCT Study

Pulp canal obliteration (PCO) is a significant complication in endodontics that can occur due to various factors. Cone beam computed tomography (CBCT) is a useful diagnostic tool for identifying root canal anatomy and variations, and guided endodontics is emerging as an alternative treatment solution for teeth with partially or entirely obliterated pulpal canals. However, the accuracy of CBCT-guided 3D-printed guides on different materials and layer thicknesses is not well understood. Therefore, this study aimed to evaluate the accuracy of guides prepared using CBCT images on 3D-printed teeth with stereolithography (SLA) using three different materials and two different layer thicknesses. This study found that 3D-printed guides were accurate and reliable for accessing 3D-manufactured obliterated teeth and reaching the apical area. No significant differences in distance or angle measurements were found when different guide materials were used, suggesting that materials can be selected based on availability and cost. These findings contribute to the knowledge base regarding the effectiveness of 3D printing technology in guided endodontics and can help to identify the most suitable materials and techniques for this application.

Application of Real-Time Augmented Reality-Guided Osteotomy and Apex Location in Endodontic Microsurgery: A Surgical Simulation Study Based on 3D-Printed Alveolar Bone Model

INTRODUCTION

Augmented reality (AR) is a novel visualization technique in which pre-generated virtual 3D content is superimposed on surgical sites. This study aimed to validate the viability of AR-guided endodontic microsurgery (ARG) and compare the changes in objective and subjective outcomes of surgical simulation using ARG and freehand endodontic microsurgery (FH) on customized 3D-printed models.

METHODS

We created and printed a customized 3D alveolar bone model with artificial periapical lesions (APLs) based on cone-beam computed tomography (CBCT). Eight models with 96 APLs were equally divided into ARG and FH groups. We planned surgical trajectories on re-scanned printed models. Four inexperienced residents (IRs) performed ARG and FH on the models and completed pre-and intraoperative confidence questionnaires for the subjective outcome. Postoperative CBCT scans of the models were reconstructed and analyzed, and all procedures were timed. We used pairwise Wilcoxon rank sum tests to compare objective outcomes. Kruskal-Wallis tests and post-hoc pairwise Wilcoxon rank sum tests were used to compare subjective outcomes.

RESULTS

Compared to the FH group, the ARG group significantly reduced deviation of the volume of bone removal, root-end resection, and deviation of bevel angle, with improved confidence of the IRs (P < 0.05); it also significantly increased surgical time and volume of unremoved APL (P < 0.05).

CONCLUSIONS

We customized an APL model through 3D printing and developed and validated a low-cost AR application framework, based on free AR software, for endodontic microsurgery. ARG allowed IRs to perform more conservative and precise surgical procedures with enhanced confidence.

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.

Guided Access Cavity Preparation Using a New Simplified Digital Workflow

INTRODUCTION

This study evaluated the precision of a simplified workflow using only preoperative cone-beam computed tomographic (CBCT) scans to gain guided access to root canals of extracted mandibular molars. A workflow using CBCT scanning associated with 3-dimensional oral scanning was used as a reference for comparison. The influence of the presence of coronal restoration in the simplified workflow was also evaluated.

METHODS

Forty-five mandibular molars were randomized into 3 groups: a control group in which digital planning was performed with CBCT and oral scanning and 2 experimental groups in which digital planning was performed only with CBCT examination. In experimental group 1, teeth had no coronal restorations, whereas in group 2 teeth presented with coronal composite restorations. After digital planning, the teeth were accessed using the guides, and a new CBCT scan was made to overlap the pre- and postoperative examinations. Precision was measured by calculating the deviation between the planned and prepared cavities in millimeters and angle. Data were compared using 1-way analysis of variance (P < .05).

RESULTS

All root canals were accessible after access preparation in all tested groups. Deviations of the planned and prepared access cavities were low, with a mean value of 0.55, 0.58, and 0.47 mm and 1.98°, 2.45°, and 1.43° for the control group, group 1, and group 2, respectively. No significant differences in millimeters or angle were observed among the 3 tested groups (P > .05).

CONCLUSIONS

The simplified digital workflow using only CBCT examination allowed a high level of precision in obtaining access in extracted molars with and without coronal restoration, presenting similar results compared with the digital workflow using CBCT and 3-dimensional oral scanning.

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.