Directed dentin conservation (DDC) refers back to the preservation of dentin constructions and will play an vital function in growing the survival price of endo-dontically handled enamel. Dynamic navigation makes use of knowledge from a CBCT scan to supply real-time visible suggestions throughout entry cavity preparation. Head-up show (HUD) know-how for the surgical working microscope has been utilized in totally different fields of medication for the reason that Nineties and is reported to boost the ergonomics throughout surgical procedures.
This case report describes using dynamic navigation and a surgical working microscope HUD for modern entry cavity preparation and optimum DDC throughout nonsurgical endodontic therapy. The significance of DDC and the potential benefits and limitations of dynamic navigation and HUD know-how for the surgical working microscope are additionally described.
DDC refers back to the preservation of selective dentin constructions. Clark and Khademi1 advised that the upkeep of selective dentin construction of excessive worth promotes optimum power in endodontically handled enamel (ETT). Worthwhile dentin areas embody the pericervical dentin (PCD), “soffits,” and “trusses.” The PCD contains dentin situated 4 mm above and under the crest of bone.
It has been proposed that the PCD performs a vital function in transferring occlusal forces alongside the foundation and that sustaining intact PCD is arguably the only most vital consider reaching long-term retention of ETT.2 A “soffit” is a lip of undercut dentin tissue left after entry cavity preparation on the degree of the pulp chamber roof.
A “truss” is a band of pulp chamber roof dentin that braces the buccal and lingual constructions of the tooth and promotes resistance to tensile and compressive forces. Each soffits and trusses might contribute to the general power of ETT.3
Using a preoperative CBCT scan to find out canal convergence profiles for the planning of the orifice-directed entry method in an effort to keep maximal PCD, soffits, and trusses was beforehand described.3
Dynamic navigation (DN) makes use of knowledge from a CBCT scan to information the clinician throughout dental procedures. Overhead stereoscopic cameras observe the place of markers connected to the dental handpiece and the affected person’s jaw. The place of the instrument tip is proven overlaid over the affected person’s digital dentition on the system’s display interface. Because the clinician strikes the instrument clinically, the digital illustration of the instrument strikes on the display, which supplies real-time steerage.
Additional particulars concerning the workflow of DN had been described by Gambarini et al.4 Over the previous couple of years, DN has been utilized primarily for the aim of accelerating the accuracy of dental implant placement. Extra not too long ago, the potential advantages of DN in growing the accuracy and effectivity of nonsurgical and surgical endodontic procedures had been investigated.
For many years, the excessive magnification and illumination of the surgical working microscope (SOM) has been a useful device in numerous fields of medication in addition to in endodontics. Carr and Murgel5 mentioned the advantages of the SOM in dentistry, which embody improved ergonomics and photograph documentation.
Through the years, the SOM utilized in totally different fields of medication has advanced to include HUD know-how. Within the Nineties, the primary microscope with HUD capabilities was launched to facilitate image-guided neurosurgery.6 HUD within the SOM entails the injection of a digital picture throughout the medical discipline of view as seen by means of the binoculars.
Injected overlaid photos embody affected person knowledge similar to pre-op imaging of curiosity or knowledge from navigation methods. Incorporating a HUD is assumed to enhance ergonomics throughout medical surgical procedures because the clinician can visualize precious info by means of the overlaid digital picture and straight visualize the surgical discipline itself.7 To the creator’s data, the medical use of a HUD in an SOM within the discipline of dentistry has by no means been reported to this point.
A 62-year-old feminine with a noncontributory medical historical past offered to the creator’s apply with a chief criticism of ache to chewing within the higher proper posterior space that started one month prior. Clinically, tooth No. 3 had an occlusal composite resin restoration demonstrating leakage and crack traces on the mesial and distal marginal ridges (Determine 1a). Two-dimensional radiographic interpretation revealed no compelling apical findings and no deep restoration, suggesting a coronal crack because the potential etiology (Determine 1b).
The affected person was referred for a small field-of-view CBCT scan. Interpretation of the CBCT quantity revealed a periapical discovering situated apical to the palatal root of tooth No. 3 (Figures 1c and 1d). Tooth No. 3 was recognized with pulp necrosis and symptomatic apical periodontitis. Remedy choices had been mentioned, and the affected person consented to nonsurgical endodontic therapy with DN steerage utilizing the Navident system (ClaroNav).
With a view to keep as a lot PCD and pulpal roof dentin as potential, 3 separate entry cavities had been deliberate utilizing the Navident software program based mostly on the canal convergence profiles: one to the distobuccal (DB) canal orifice, one to the palatal (P) canal orifice, and one to the mesiobuccal (MB1) canal orifice (Figures 1e to 1g).
After native anesthesia, DN registration and calibration procedures had been accomplished: After placement of the rubber dam isolation, the Navident fiducial marker was positioned onto the maxilla, and the dentition was registered in an effort to merge the CBCT knowledge to the precise medical discipline.
The handpiece and bur had been then calibrated as per Navident protocol. Entry cavity preparation utilizing DN was accomplished below the SOM with the simultaneous use of an experimental HUD prototype (Zumax Medical Co, Ltd) (Figures 2a and 2b) utilizing a #859.31.010 needle tapered diamond bur (Brasseler USA).
The entry cavity preparation to the DB canal with simultaneous DN as seen by means of the SOM binoculars is proven in Determine 2c. Following completion of straight-line entry preparations to the MB1, DB, and P canals, the preplanned digital entry path to the MB1 canal was re-angulated towards the MB2 canal (Determine 3).
The MB2 canal was then accessed in the identical method utilizing DN and the SOM HUD. Glide paths and dealing lengths utilizing the Ryder S3 digital apex locator (MedicNRG) had been obtained. Instrumentation to a measurement #20.06 within the buccal canals and #25.06 within the palatal canal was carried out utilizing the DCTaper rotary file system (SS White Dental). Disinfection was achieved utilizing full-strength (8%) sodium hypochlorite and the EndoActivator (Dentsply Sirona). The canals had been dried with paper factors and medicated with calcium hydroxide.
The entry cavities had been quickly restored with Cavit Non permanent Filling Materials (3M) and a bonded composite resin restoration coronally. The affected person returned 4 weeks later with a completely asymptomatic and purposeful tooth. The canals had been re-accessed and obturated utilizing heat vertical compaction of gutta-percha with AH Plus sealer (Dentsply Sirona). Figures 4a to 4c present the three separate orifice-directed entry cavities with the upkeep of pulpal roof dentin. After the applying of 37% acid etch, Futurabond DC (VOCO) and LuxaCore Z Twin (DMG America) had been used to completely restore the tooth.
A advice for an onlay oblique restoration was made. Determine 4d exhibits the postoperative radiograph, demonstrating the conservative entry cavities, the preservation of the PCD, and the truss (black arrow).
Regardless of gaining curiosity from clinicians worldwide, minimally invasive approaches to endodontic entry cavity preparation are nonetheless a topic of controversy. Conclusions from in vitro research are sometimes referenced to argue towards minimally invasive endodontics.8 Sadly, the inherent limitations of those in vitro research utilizing mechanical-failure experiments result in important unreliability when translating outcomes from benchtop experiments to medical conditions.9
Lengthy-held issues concerning the necessity of surgical invasiveness throughout the medical neighborhood a long time in the past have led to the eventual acceptance of minimally invasive remedy.10 Certainly, removing or manipulation of extra human tissue throughout numerous surgical procedures needs to be justified with demonstrable and compelling high-level proof. In endodontics, the duty of demonstrating advantages needs to be on those that advocate for extra dentin removing throughout entry cavity preparation fairly than those that advocate for much less.
Randomized management trials are the supply of the strongest proof to information clinicians in decision-making for various medical interventions.11 Sadly, there are at present no such medical research out there that counsel that minimally invasive approaches to entry cavity preparation might provide a bonus over standard ones or vice versa.
Then again, appraisal of the subsequent finest out there proof, which incorporates observational medical research with medium to long-term follow-up occasions, suggests in any other case.12-21 These research persistently report that the principle causes for extraction of ETT most frequently embody recurrent caries or restorative, structural, or periodontal failures, with failures of true endodontic origin reported least ceaselessly.
These findings counsel that DDC needs to be one of many most important objectives of endodontic therapy to attain tooth longevity. As newer applied sciences have emerged, similar to heat-treated rotary information, CBCT, DN, and improved irrigation and obturation strategies, overcoming previous limitations which have constrained the necessities for conventional entry cavity designs is now potential.
The experimental HUD prototype used on this case report consisted of a show system projecting a mirror picture of the Navident laptop display (Determine 4e) that was overlaid in actual time straight into the medical discipline of view as seen by means of the SOM utilizing a custom-made optical module. Future functions of the HUD within the SOM contain the injection of apex locator studying knowledge or pre-op imaging of curiosity and the overlay of digital 3D fashions of dental constructions utilizing synthetic intelligence and picture processing.
Using DN to acquire optimum DDC was additionally demonstrated on this case report. DN allowed for the planning and execution of ideally designed entry cavities to take care of as a lot PCD and pulpal roof as potential whereas nonetheless reaching the organic aims of endodontic therapy. Primarily based on the canal convergence profiles, straight-line accesses had been achieved individually to every canal orifice, which allowed for secure instrumentation utilizing heat-treated NiTi rotary information.
Though the identical procedural final result can routinely be achieved by skilled clinicians utilizing free-hand entry cavity preparation, DN has the potential to streamline the method and considerably lower therapy time and frustration.
One other method to guided endodontics entails using 3D printed static guides. Potential limitations of static guides in endodontics embody a scarcity of interocclusal distance to accommodate for longer drills, the shortcoming to make use of high-speed drills or burs, and the wait time concerned with the fabrication of the static information(s), which complicates same-day endodontic therapy. The necessity for the fabrication of a number of guides in an effort to entry all canals in multi-rooted enamel and the shortcoming to simply change the therapy plan in the course of the guided process in gentle of latest medical info or challenges are additionally limiting elements.22
These limitations are often not current with DN. Certainly, an entry cavity will be deliberate inside a couple of minutes, making DN supreme for emergency therapy. The Navident system can be utilized with many various instrument ideas, together with high-speed and low-speed burs, ultrasonic ideas, or piezo surgical ideas. Moreover, DN permits for instantaneous modifications to the therapy plan in the course of the process (Determine 3).
The accuracy of DN for endodontic procedures has by no means been evaluated in vivo. Compiled outcomes from in vitro research within the fields of implantology and endodontics, in addition to outcomes from in vivo research in implantology, counsel that DN at present has an error vary of roughly 0.5 to 1 mm.23-29
Though DN affords an amazing profit in growing the accuracy of various medical procedures, its present error vary stays excessive for endodontic functions. Moreover, the present workflow for DN, as really helpful by manufacturing corporations, entails the overall dedication of the clinician’s consideration to the system’s laptop display interface, which is positioned away from the surgical discipline.
Because the clinician commits full consideration to DN throughout entry cavity preparation, different precious info, similar to direct visible suggestions from the dentin map, can’t be accessed. With a HUD, the clinician can use DN as an adjunct with out having to look away from the surgical discipline. This freedom permits the clinician to selectively concentrate on totally different precious items of knowledge with none compromise and will assist improve the accuracy of entry cavity preparations with optimum DDC versus utilizing DN alone.
Moreover, having to search for at a pc display throughout DN procedures might really feel unnatural to the clinician who’s used to trying on the surgical discipline by means of the SOM.
Combining the advantages of each DN and SOM concurrently additionally permits for minimizing wasted actions and time in addition to maximizing optimum ergonomics.
This case report demonstrated the potential of DN to arrange endo-dontic entry cavities effectively and safely with maximal DDC. The SOM HUD additional demonstrated enhanced ergonomics. Future medical research are required to find out the accuracy of DN for endodontic entry cavity preparations.
The creator want to thank Drs. Viraj Vora and Dale Jung for his or her assist with reviewing the manuscript.
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ABOUT THE AUTHOR
Dr. Nadeau graduated with a DDS diploma from Dalhousie College and earned a Grasp’s of Science in endodontics from the College of Toronto. He has developed specific pursuits in dynamic navigation for endodontics, ergonomics in microscope dentistry, restoratively pushed endodontics, and medical decision-making. Dr. Nadeau is in full-time non-public apply in Kingston, Ont, Canada. He will be reached at firstname.lastname@example.org.
Disclosure: Dr. Nadeau is a guide for Zumax Medical Co, Ltd and ClaroNav.