Guided endodontics: accuracy of access cavity preparation and discrimination of angular and linear deviation on canal accessing ability—an ex vivo study

Abstract

Background Guided endodontics technique has been introduced for years, but the accuracy in different types of teeth has yet to be assessed. The aim of this study is to evaluate the accuracy of three dimensional (3D)-printed endodontic guides for access cavity preparation in different types of teeth, and to evaluate the predictive ability of angular and linear deviation on canal accessibility ex vivo. Method Eighty-four extracted human teeth were mounted into six jaw models and categorised into three groups: anterior teeth (AT), premolar (P), and molar (M). Preoperative cone beam computed tomography (CBCT) and surface scans were taken and matched using implant planning software. Virtual access cavity planning was performed, and templates were produced using a 3D printer. After access cavities were performed, the canal accessibility was recorded. Postoperative CBCT scans were superimposed in software. Coronal and apical linear deviations and angular deviations were measured and evaluated with nonparametric statistics. The receiver operating characteristic (ROC) curve was used to evaluate the predictive ability of angular and linear deviation for canal accessibility in SPSS v20. Results A total of 117 guided access cavities were created and 23 of them were record as canal inaccessibility, but all canals were accessible after canal negotiation. The average linear deviation for all groups was 0.13 ± 0.21 mm at coronal position, 0.46 ± 0.4 mm at apical position, and 2.8 ± 2.6° in angular deviation. At the coronal position, the linear deviations of the AT and P groups were significantly lower than M group deviation (P < 0.05), but no statistically significant difference between AT group and P group. The same results were found in linear deviation at the apical position and in angular deviation. The area under the ROC curve was 0.975 in angular deviation, 0.562 in linear deviation at the coronal position, and 0.786 at the apical position. Statistical significance was noted in linear deviation at the apical position and in angular deviation (P < 0.001). Conclusions In conclusion, this study demonstrated that the accuracy of access cavity preparation with 3D-printed endodontic guides was acceptable. The linear and angular deviations in the M group were significantly higher than those in the other groups, which might be caused by the interference of the opposite teeth. Angular deviation best discriminated the canal access ability of guided access cavity preparation. Graphical Abstract

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

“…This can explain the slightly higher deviation values obtained apically. The average angular deviation was below the range reported by other authors [13,14,28].…”

“…The authors reported achieving minimally invasive access up to the middle of the root; however, no data was available regarding its accuracy. On the other hand, the accuracy of conventional guides used for guided endodontics has been assessed in several studies, showing mean apical deviation values smaller than 0.5 mm [13,14,[26][27][28] with a mean angular deviation between 1.59 • and 1.81 • [13,14]. Although it is difficult to compare the present study with other studies due to differences in the protocol and heterogeneous measuring methods, the deviation measurements obtained with a sleeveless guide do not seem to differ substantially from those of conventional guides.…”

Static and Dynamic Navigation - “The Future Stars”

“…[11] Subsequently a template is fabricated using 3D printing. [12] (Fig- 1) A template known as an endodontic guide is created to direct drills into pre-planned sites for localizing and exploring root canal orifices or for trephining bone and resealing root ends. These are used exclusively in Static Guided Endodontics.…”

“…3D printing helps in printing of customized endodontic guides. [14] The commercially available burs and drills include Straumann drill, SS White Endo bur, munce bur [12] . They are between 25 and 35 mm long to integrate the sleeve's length, and between 1.2 and 1.5 mm wide.…”

Clinical Endodontic Applications of 3D Printing, A Review

“…Su et al in their ex vivo study, also found very low linear deviation in all groups (anteriors, premolars, and molars); however, they found that the apical position had more deviation than the coronal (0.46 mm. vs. 0.13 mm); nonetheless, al canals were accessible and no root canal perforation was observed [22]. This review included one observational study by Buchgreitz et al that found that guided endodontic access can be precise irrespective of sex, age, tooth number, degree of obliteration, and previous attempts to find and negotiate the root canal in single-rooted teeth [18].…”