Approval or consent to perform this study was not required since the use of patients&#39; data is not applicable. In this study, DICOM data from a maxillary model consisting of extracted, de-identified human teeth are used. Teeth were extracted due to reasons not related to this study.
1. Virtual access cavity planning
<ol>
	<li>Start the digital planning program.</li>
	<li>Right-click on Expert to choose the advanced mode.</li>
	<li>Right-click on N...

<ol>
	<li>Andreasen, F. M., Zhijie, Y., Thomsen, B. L., Andersen, P. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Occurrence+of+pulp+canal+obliteration+after+luxation+injuries+in+the+permanent+dentition.">Occurrence of pulp canal obliteration after luxation injuries in the permanent dentition.</a> Endodontics &amp; Dental Traumatology. 3 (3), 103-115 (1987).</li><li>Fleig, S., Attin, T., Jungbluth, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Narrowing+of+the+radicular+pulp+space+in+coronally+restored+teeth.">Narrowing of the radicular pulp space in coronally restored teeth.</a> Clinical Oral Investigation. 21 (4), 1251-1257 (2016).</li><li>Linu, S., Lekshmi, M. S., Varunkumar, V. S., Sam Joseph, V. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Treatment+outcome+following+direct+pulp+capping+using+bioceramic+materials+in+mature+permanent+teeth+with+carious+exposure:+A+pilot+retrospective+study.">Treatment outcome following direct pulp capping using bioceramic materials in mature permanent teeth with carious exposure: A pilot retrospective study.</a> Journal of Endodontics. 43 (10), 1635-1639 (2017).</li><li>Robertson, A., Andreasen, F. M., Bergenholtz, G., Andreasen, J. O., Noren, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Incidence+of+pulp+necrosis+subsequent+to+pulp+canal+obliteration+from+trauma+of+permanent+incisors.">Incidence of pulp necrosis subsequent to pulp canal obliteration from trauma of permanent incisors.</a> Journal of Endodontics. 22 (10), 557-560 (1996).</li><li>Kiefner, P., Connert, T., ElAyouti, A., Weiger, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Treatment+of+calcified+root+canals+in+elderly+people:+a+clinical+study+about+the+accessibility,+the+time+needed+and+the+outcome+with+a+three-year+follow-up.">Treatment of calcified root canals in elderly people: a clinical study about the accessibility, the time needed and the outcome with a three-year follow-up.</a> Gerodontology. 34 (2), 164-170 (2017).</li><li>Cvek, M., Granath, L., Lundberg, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Failures+and+healing+in+endodontically+treated+non-vital+anterior+teeth+with+posttraumatically+reduced+pulpal+lumen.">Failures and healing in endodontically treated non-vital anterior teeth with posttraumatically reduced pulpal lumen.</a> Acta Odontologica Scandinavica. 40 (4), 223-228 (1982).</li><li>Zehnder, M. S., Connert, T., Weiger, R., Krastl, G., Kuhl, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Guided+endodontics:+accuracy+of+a+novel+method+for+guided+access+cavity+preparation+and+root+canal+location.">Guided endodontics: accuracy of a novel method for guided access cavity preparation and root canal location.</a> International Endodontic Journal. 49 (10), 966-972 (2016).</li><li>Moreno-Rabi&#233;, C., Torres, A., Lambrechts, P., Jacobs, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+applications,+accuracy+and+limitations+of+guided+endodontics:+a+systematic+review.">Clinical applications, accuracy and limitations of guided endodontics: a systematic review.</a> International Endodontic Journal. 53 (2), 214-231 (2020).</li><li>Buchgreitz, J., Buchgreitz, M., Bj&#248;rndal, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=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.">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.</a> International Endodontic Journal. 52 (5), 559-568 (2019).</li><li>Dula, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SADMFR+guidelines+for+the+use+of+cone-beam+computed+tomography/+digital+volume+tomography.">SADMFR guidelines for the use of cone-beam computed tomography/ digital volume tomography.</a> Swiss Dental Journal. 124 (11), 1169-1183 (2014).</li><li>Ender, A., Zimmermann, M., Mehl, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy+of+complete-+and+partial-arch+impressions+of+actual+intraoral+scanning+systems+in+vitro.">Accuracy of complete- and partial-arch impressions of actual intraoral scanning systems in vitro.</a> International Journal of Computerized Dentistry. 22 (1), 11-19 (2019).</li><li>Krug, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Guided+endodontics:+a+comparative+in+vitro+study+on+the+accuracy+and+effort+of+two+different+planning+workflows.">Guided endodontics: a comparative in vitro study on the accuracy and effort of two different planning workflows.</a> International Journal of Computerized Dentistry. 23 (2), 119-128 (2020).</li><li>Chen, L., Lin, W. S., Polido, W. D., Eckert, G. J., Morton, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy,+reproducibility,+and+dimensional+stability+of+additively+manufactured+surgical+templates.">Accuracy, reproducibility, and dimensional stability of additively manufactured surgical templates.</a> The Journal of Prosthetic Dentistry. 122 (3), (2019).</li><li>Tahir, N., Abduo, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+in+vitro+evaluation+of+the+effect+of+3D+printing+orientation+on+the+accuracy+of+implant+surgical+templates+fabricated+by+desktop+printer.">An in vitro evaluation of the effect of 3D printing orientation on the accuracy of implant surgical templates fabricated by desktop printer.</a> Journal of Prosthodontics. , (2022).</li><li>Torres, A., Lerut, K., Lambrechts, P., Jacobs, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Guided+endodontics:+Use+of+a+sleeveless+guide+system+on+an+upper+premolar+with+pulp+canal+obliteration+and+apical+periodontitis.">Guided endodontics: Use of a sleeveless guide system on an upper premolar with pulp canal obliteration and apical periodontitis.</a> Journal of Endodontics. 47 (1), 133-139 (2021).</li><li>Dong, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accuracy+of+in+vitro+mandibular+volumetric+measurements+from+CBCT+of+different+voxel+sizes+with+different+segmentation+threshold+settings.">Accuracy of in vitro mandibular volumetric measurements from CBCT of different voxel sizes with different segmentation threshold settings.</a> BMC Oral Health. 19 (1), 206 (2019).</li><li>Oh, S. -. M., Lee, D. -. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validation+of+the+accuracy+of+postoperative+analysis+methods+for+locating+the+actual+position+of+implants:+An+in+vitro+study.">Validation of the accuracy of postoperative analysis methods for locating the actual position of implants: An in vitro study.</a> Applied Sciences. 10 (20), 7266 (2020).</li><li>Connert, T., Weiger, R., Krastl, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Present+status+and+future+directions+-+Guided+endodontics.">Present status and future directions - Guided endodontics.</a> International Endodontic Journal. , (2022).</li></ol>

The introduction of template-aided access cavity preparations in endodontics has brought immense progress to non-surgical endodontic treatment in teeth with PCO. Conventional access cavity preparation can be very time consuming5 and is prone to error in cases with severe PCO. In vitro studies and clinical case reports demonstrate the feasibility of the guided endodontics approach, generating satisfying results in terms of root canal detection and an overall low deviation between the plann...

Pulp canal obliterations (PCO) are signs of vital pulp, and are often observed after dental trauma1 or as a response to stimuli like caries, restorative procedures2, or vital pulp therapy3. When no clinical or radiographic signs of pathology are present, root canal treatment is not indicated. In the long term, however, the remaining pulp tissue can develop a pathosis4. In cases where clinical or radiographic signs of pulpal or apical pathology are present, non-surgical root canal treatment would be the treatment of choice for tooth preservation. 
For a successful outcome of the root canal treatment, the preparation of an adequate access cavity is crucial. Teeth with PCO needing a root canal treatment are difficult to treat, even for dentists that are specialized in the field of endodontics5. Attempting to locate a calcified root canal may result in a high loss of tooth structure and thus weakening or even perforation of the root. This reduces the prognosis of the tooth, and extraction may be indicated6.
As template-based (static) navigation is already successfully used in oral implantology, its application in endodontics was first described in the literature a few years ago7. Since then, numerous case reports and studies have demonstrated the benefits of template-aided endodontic access cavity preparation in cases with PCO8,9. 
The aim of this work is to present the technique of guided access cavity preparation using guided endodontics. For research purposes, a treatment evaluation (determination of angular and spatial deviation between planned and performed access cavity) is possible after a postoperative CBCT scan, which is also presented in this article.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Accuitomo 170</td>
			<td>Morita Manufacturing</td>
			<td>NA</td>
			<td>CBCT machine</td>
		</tr>
		<tr>
			<td>coDiagnostiX</td>
			<td>Dental Wings Inc</td>
			<td>Version 10.4</td>
			<td>Planning software, which is mainly intended for implant surgery. Endodontic access cavities can be planned by adding the utlized bur to the implant database</td>
		</tr>
		<tr>
			<td>Endoseal drill</td>
			<td>Atec Dental GmbH</td>
			<td>NA</td>
			<td>Carbide bur, which is used for the guided access cavity preparation</td>
		</tr>
		<tr>
			<td>StecoGuide Endo-Sleeve</td>
			<td>steco-system-technik</td>
			<td>REF M.27.28.D100L5</td>
			<td>Sleeves, which are inserted into the fabricated template</td>
		</tr>
		<tr>
			<td>TRIOS 3</td>
			<td>3Shape A/S</td>
			<td>NA</td>
			<td>Surface scanner</td>
		</tr>
		<tr>
			<td>P30</td>
			<td>Straumann</td>
			<td>NA</td>
			<td>3D Printer</td>
		</tr>
		<tr>
			<td>P pro Surgical Guide Clear</td>
			<td>Straumann</td>
			<td>NA</td>
			<td>Light-curing resin for the additive manufacturing</td>
		</tr>
	</tbody>
</table>

guided endodontics: three-dimensional planning and template-aided preparation of endodontic access cavities

Pulp canal obliterations (PCO) are often a consequence of dental trauma, such as luxation injuries. Even though dentin apposition is a sign of vital pulp, pulpitis or apical periodontitis may develop in the long term. Root canal treatment of teeth with severe PCO and pulpal or periapical pathosis is challenging for general practitioners and even for well-equipped endodontic specialists. To ensure detection of the calcified root canal and avoid excessive loss of tooth structure or root perforation, static navigation using templates ("Guided Endodontics") was introduced a few years ago. The general workflow includes three-dimensional imaging using cone-beam computed tomography (CBCT), a digital surface scan, and superimposition of both in a planning software. This is followed by virtual planning of the access cavity and the design of a template that will guide the drill to the desired target point. To do this, a true-to-scale virtual image of the drill must be placed in a way that the tip of the drill reaches the orifice of the calcified root canal. Once the template has been fabricated using computer-aided design and computer-aided manufacturing (CAD/CAM) or a 3D printer, guided preparation of the access cavity can be performed clinically. For research purposes, a postoperative CBCT image can be used to quantify the accuracy of the access cavity performed. This work aims to present the technique of static guided endodontics from imaging to clinical implementation.

Figure 10A shows the occlusal view of a prepared endodontic access cavity in a first maxillary molar after template-aided access cavity preparation of the mesio-buccal canal. Figure 10B shows the insertion of three endodontic handfiles to confirm successful root canal detection after preparation of the palatal and disto-buccal access cavities. After matching the postoperative CBCT data to the preoperative planning data, virtual bur placement generates informatio...

Watch this Scientific Journal Video about Guided Endodontics: Three-Dimensional Planning and Template-Aided Preparation of Endodontic Access Cavities at JoVE.com

Guided Endodontics: Three-Dimensional Planning and Template-Aided Preparation of Endodontic Access Cavities

Guided endodontics describes a template-aided approach for access cavity preparation. The procedure requires cone-beam computed tomography and a surface scan to produce a template. An incorporated sleeve guides the drill to the target point. This allows the preparation of minimally invasive endodontic access cavities in calcified teeth.

Pulp canal obliterations (PCO) are often a consequence of dental trauma, such as luxation injuries. Even though dentin apposition is a sign of vital pulp, ...

Teeth with severe pop canal calcification and apical pathosis can be very challenging to treat conventionally. Template guided access preparation is a reliable technique that enables tooth preservation. Excess cavity preparation using a template-based approach is minimally invasive, and the access can be accomplished by a less experienced operator.To begin, start the digital planning program. Right click on Expert to choose the advanced mode. Right click on New to open a new case.Select the folder with DICOM image data to import the image data to the software. Adjust the Hounsfield unit thresholds if necessary for optimal visualization. Click on Create Dataset to complete the data import.Choose the type of planning by left clicking on Maxilla or Mandible and name the planning. Click on Edit Segmentations to start the image segmentation process. Choose the axial view by left clicking on Axial in the upper left box.Click on Density Measurement to measure the high radio pack tooth surface in the surrounding non-radio-pack states. Calculate the mean values between both densities. Set the lower threshold to the determined mean value.Click on 3D Reconstruction. Segment the dentition with the flood fill tool and name the segmentation as desired. Complete the segmentation by clicking on Close Module.Add a model scan by selecting Add, then click Object, followed by Model Scan. Import the STL file from the digital surface scan. Choose Align to Other Object.Select the performed segmentation. Choose three different matching points for landmark registration in the 3D view in both data sets, the segmentation, and the surface scan. Verify correct registration in all planes and complete registration.Import the endodontic bur into the implant's database. Add an implant to plan the access to the root canal. Position the bur and the desired angulation into the required depth and verify in all planes.Add the corresponding sleeve to the bur. Select Object, then click Add, followed by Surgical Guide to design the template as preferred. Export the template as a STL file and manufacture it with a 3D printer.Check the fit of the template on the dentition. Check the fit of the sleeve in the template. Mark the enamel at the access cavity site.Dye may be used at the bur's tip. Remove the enamel at the access cavity site without using the template or endodontic bur. Use a diamond bur instead until dentin is exposed.Place the sleeve containing template on the dental arch. Insert the bur into the handpiece that was used for the planning. Perform the access cavity preparation with template guidance.Use the pre-operative cone beam computed tomography settings to create post-operative image data. Start a new case planning. Import the image data analog to the pre-operative planning.Click on Edit Segmentations. Set the lower threshold to the determined mean value which was calculated for the pre-operative data. Use the Flood Fill tool to segment the dentition.Complete the segmentation by clicking on Close Module. Open the pre-operative planning. Select Plan, then click Treatment Evaluation.Select Post-operative volume data set. Load the correct postoperative data set and choose the generated segmentation. Align pre and postoperative cone beam computed tomography data by choosing three different regions for landmark registration.Verify correct registration in all plains and complete registration. Place the virtual endodontic bur in the direction of performed access cavity preparation and check in all the planes. The occlusal view of a prepared endodontic access cavity in a first maxillary molar after templated access cavity preparation of the mesiobuccal canal insertion of three endodontic hand files confirmed successful root canal detection after preparation of the palatal and distobuccal access cavities.After matching the post-operative cone beam computed tomography data to the pre-operative planning data, virtual bur placement generated information about the deviation. Here the angular deviation is 0.7 degrees, 0.74 millimeters 3D deviation at the base of the bur and 0.87 millimeters 3D deviation at the tip of the bur. Following this procedure, endodontic treatment of a invaginatus, removal of manual tri exit aggregate or fiber posts may be enabled.

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Research

JoVE Journal

Medicine

3.9K 조회수.  University of Basel. 심한 팝 운하 석회화 및 정점 병증이있는 치아는 전통적으로 치료하기가 매우 어려울 수 있습니다. 템플릿 안내 접근 준비는 치아 보존을 가능하게 하는 신뢰할 수 있는 기술입니다. 템플릿 기반 접근 방식을 사용한 과도한 캐비티 준비는 최소 침습적이며 경험이 적은 작업자가 접근할 수 있습니다.시작하려면 디지털 계획 프로그램을 시작하십시오. Expert를 마우스 오른...