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CASE REPORT
Year : 2021  |  Volume : 9  |  Issue : 3  |  Page : 206-210

Application of CBCT data and three-dimensional printing for endodontic diagnosis and treatment: Three case reports


Department of Conservative Dentistry and Endodontics, St Joseph Dental College, Eluru, Andhra Pradesh, India

Date of Submission13-Jun-2021
Date of Acceptance17-Jul-2021
Date of Web Publication30-Nov-2021

Correspondence Address:
Dr. Srinidhi Vishnu Ballulaya
Department of Conservative Dentistry and Endodontics, St Joseph Dental College, Eluru, Andhra Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njecp.njecp_20_21

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  Abstract 


The combined CBCT and 3-d printing have found its endodontic application in pre-surgical planning models, endodontic access guides and localization of osteotomy preparation site. This article reports a series of three cases where this combined technology have been used. The first case report is of radicular dens invaginatus which was diagnosed by using cone-beam computed tomography (CBCT) imaging and 3D plastic models of the tooth. The case was managed successfully by the combination of both surgical and non-surgical endodontic treatment. The second case report is the guided access preparation of lower anterior teeth. A 3D printed template was designed with the CBCT scan for the guided access cavity preparation and was compared with the conventional endodontic access cavity preparation. The third case report is the surgical template guided hemisection. A 3D surgical template was designed which allowed precise angulation of the bur and minimized the excess removal of tooth structure. Thus, the combined use of CBCT and 3D printing enabled visualization of complex root canal anatomies and allowed precise and accurate treatment.

Keywords: 3D printed template, cone beam computed tomography, guided access, radicular dens invaginatus, surgical template guided hemisection


How to cite this article:
Ballulaya SV, Taufin N, Deepthi N, Devella VB. Application of CBCT data and three-dimensional printing for endodontic diagnosis and treatment: Three case reports. Niger J Exp Clin Biosci 2021;9:206-10

How to cite this URL:
Ballulaya SV, Taufin N, Deepthi N, Devella VB. Application of CBCT data and three-dimensional printing for endodontic diagnosis and treatment: Three case reports. Niger J Exp Clin Biosci [serial online] 2021 [cited 2022 Jul 7];9:206-10. Available from: https://www.njecbonline.org/text.asp?2021/9/3/206/331552




  Introduction Top


Diagnosis in endodontics has been relied on the classical signs and symptoms of pulpal and periapical diseases along with conventional tests such as percussion test, thermal tests, transillumination, test cavity, and radiographs. Intraoral periapical radiographs (IOPAs) provided little information which was essentially two-dimensional (2D) image resulting from compression of 3D structures. Other disadvantages of conventional radiograph are geometrical distortion, anatomical noise, difficult interpretation, and lack of coordination between the size of histological defect and apical periodontitis image.[1],[2]

Cone-beam computed tomography (CBCT) in endodontics provides 3D image with narrow field of view, utilizes low radiation, and provides high-resolution image for endodontic diagnosis and treatment planning.[3] Recently 3D printing technique utilizing CBCT scanned images allow fabrication of models utilizing additive manufacturing technique. Essentially, 3D printing technique comprises the following three steps: digital data acquisition using an intraoral scanner and/or a cone-beam computed tomography (CBCT), data processing and design within a software application, and manufacturing by printing.[4],[5]

CBCT along with 3D printing has found the following applications in endodontics: surgical guides, guided endodontic access, autotransplantation, 3D bioprinting for regenerative procedures, educational models, and clinical simulation.[6] This article is an attempt to highlight the application of CBCT and 3D printing in diagnosis and treatment planning.


  Case Reports Top


The three patients reported in this case report visited St. Joseph Dental College and Hospital, Eluru, India, for treatment of their problematic tooth. After diagnosis, treatment alternatives were explained and informed consent was taken.

CBCT specification

A CBCT rainbow™ (Dentium Co., Ltd., Gyeonggi-do, Korea) scan with a constant thickness of 1.00 mm per slice, and with exposure parameters of 80 kV, 7.0 mA, and 17 s, with field of view of 5 cm × 5 cm was employed.

Three-dimensional printing specification

For dens invaginatus, the 3D Dental Lab Scanner (Medit T500, Seoul, Korea) was used to obtain a stereolithography file of the arch, the 3D implant planning Maestro 3D software (AGE SOLUTIONS S.R.L., Pontedera, Italy), and the model was done by photopolymer resin with the help of Form 2 SLA 3D Printer (IMIK Formlabs, Coimbatore, India).

For guided access and hemisection, the 3D Dental Lab Scanner (Medit Lab Scan T500, Seoul, Korea) was used to obtain a stereolithography file of the arch, DDS-Pro digital software (JST sp.z.o.o, Czestochowa, Poland) was used to design the splints, and Anycubic Photon 2.0-SLA Printer (Shenzhen Anycubic Technology Co. Ltd., Guangdong, China) was used to fabricate the guides. The guides were made using Anycubic clear ultraviolet light-based resin (Shenzhen Anycubic Technology Co. Ltd., Guangdong, China).

Case #1: Radicular dens invaginatus

A 33-year-old patient reported swelling over the upper left canine region. The patient reported no significant medical history, and there was no history of dental trauma. On clinical examination, the canine was discolored with unusual morphology of crown. There was no evidence of caries or developmental pit/groove/fissure in the lingual crown portion. Swelling was noted over the attached gingival, and the vestibule was slightly obliterated. On periodontal probing, periodontal pocket depth of 5 mm was noted over the labial aspect. The tooth was not mobile but was tender on percussion. The thermal test provided negative response. IOPA revealed wide tortuous canal with open apex and bone resorption in apical and lateral mesial aspect of root [Figure 1]a. In addition, radicular extension on the mesial side extending from cervical to middle portion of root suggestive of Oehlers type IIIa dens in dente was noted. No appreciable communication was noted between the main canal and dens in dente. CBCT was planned for proper diagnosis and treatment planning.
Figure 1: Clinical and radiographic images of dens invaginatus.(a)Pre-operative radiograph of the tooth (b)Axial and sagittal sections of CBCT showing the lesion extent (c,d)3D Image of the tooth (e)3D model of the tooth (f) root end resection done (g)Biodentine is packed in the lesion and retrograde filling is done after the endodontic treatment (h) Immediate post-operative radiograph image.

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In CBCT images, both sagittal and axial sections revealed radiopaque line sac in the coronal and middle third of the mesial aspect of root. Axial sections apically demonstrated periapical lesion extending coronally into the sac. The main canal outline was long oval, tortuous, and narrow mesiodistally. The apex was wide open [Figure 1]b. The patient was informed of the condition and was suggested treatment alternatives.

Since it was important to examine the tooth physically and the latter may be used for educational purposes, 3D printing of the tooth was performed [Figure 1]c and [Figure 1]d. Evaluation of 3D model demonstrated uneven and rough surface on the labial and mesial aspect of the model with very thin lining of the sac extending up to middle third of root [Figure 1]e. The apex was large open which necessitated changing the treatment plan from convention root canal treatment to combine the periapical surgery to obtain better seal.

In the first appointment after rubber dam isolation, access cavity was prepared inclining the bur distally to obtain straight-line access. The canal was irrigated with 3% sodium hypochlorite (ChlorCid, Ultradent Products Inc.) before introducing file. Working length was determined and canal was instrumented with H-file (Dentsply Maillefer, Ballaigues, Switzerland) taking care not to remove excessive dentin. After instrumentation up to 80 H-file, the canal was filled with calcium hydroxide paste (UltraCal; Ultradent Products Inc.). After 2 weeks of intracanal dressings, the canal was re-instrumented and ultrasonic agitation of sodium hypochlorite was performed. Smear layer was removed by alternate irrigation of sodium hypochlorite and 17% ethylenediaminetetraacetic acid (EDTA) (Pulpdent EDTA Solution, USA). The canal was dried with paper points (Dentsply Maillefer, Ballaigues, Switzerland), and obturation was performed with customized gutta-percha cone using Sealapex (SybronEndo, The Netherlands) as root canal sealer. Additional gutta-percha was inserted after using root canal spreader. Periapical surgery was planned after 1 week.

The patient was anesthetized with 2% lidocaine with epinephrine (1:80,000) (Xylocaine® Dentsply Maillefer) with multiple infiltration at the surgical site. After profound anesthesia, rectangular flap was elevated. On examination of surgical site, there was no periodontal attachment on the labial side (because of the presence of enamel like lining) [Figure 1]f. The patient was explained regarding the prognosis and the patient insisted on continuation of treatment. The granulation tissue was curetted in the periapical as well as the invagination region. Since the apical root was thin, no attempt was made to do root resection and sufficient access was there to perform root-end cavity preparation and retrofilling. The gutta-percha was removed using ultrasonic retro tips (KiS TIPS, SybronEndo, The Netherlands) and filled with Biodentine (Biodentine™, Septodont, St. Maur-des-Fosses, France). The enamel like lining of the sac was removed on the mesial side and smoothened to prevent aggregation of tissue necrotic debris in the invagination region. The sac was eliminated by placement of Biodentine [Figure 1]g and confirmed radiographically [Figure 1]h. The flap was repositioned and sutured.

Case#2: Guided access preparation

A 51-year-old male patient reported pain in the lower incisors. On clinical examination, both mandibular central incisors were attrited incisally with cervical abrasion and crown discoloration. The attached gingival was swollen, and there was no pus exudates coming from the gingival sulcus. The probing depth was normal, and both central incisors were tender on percussion. The thermal tests were negative. IOPA revealed significant loss of dentin over the pulp chamber and narrow calcified canals from middle third of root. Periapical radiolucencies were associated with apices of both the central incisors [Figure 2]a. As part of postgraduate training, the patient was informed regarding the guided access preparation and need for CBCT.
Figure 2: (I) Clinical and radiographic images of guided access opening: (a) preoperative radiograph of the tooth, (b) endodontic guide designing-cast scan, (c) endodontic guide planning for the bur length and orientation, (d) three-dimensional endodontic guide template designing–DICOM image, (e) access opening done with the help of endodontic guide, (f) the conventional endodontic access opening showing off centricity, (g) the guided endodontic access opening showing minimal loss of tooth structure. (II) Clinical and radiographic images of surgical template-guided hemisection: (h) preoperative radiograph of the tooth, (i) CBCT of the quadrant for the template designing, (j) DICOM image of the CBCT scan and the template, (k) three-dimensional surgical template, (l) surgical template-guided hemisection of the tooth, (m) postoperative image of the tooth

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CBCT sagittal image denoted Weine's type IV canal configuration, and the periapical lesion was limited to apical region of tooth on the buccal aspect. Buccal canal was larger compared to lingual, and the latter joined the buccal canal in the apical one-third.

Alginate impression of lower arch was taken, and a gypsum dental model was created and scanned. Both CBCT imaging and model scans were aligned and processed [Figure 2]b, [Figure 2]c, [Figure 2]d. A virtual copy of a drill with a diameter of 0.8 mm and a length of 12 mm was superimposed onto the scans in a position that allowed its access to the identified root system [Figure 2]c. The right central incisor was subjected to guided access preparation [Figure 2]g, and conventional access cavity was performed in right lateral incisor [Figure 2]f. This served for comparison between the two access cavity techniques.

The fit of the template was checked intraorally. After obtaining anesthesia, teeth were isolated with rubber dam and the operator stabilized the template by holding it against teeth. Tapered fissure bur with tip diameter of 0.8 mm and length of 15 mm was used with high-speed handpiece and the sleeve in the template was adjusted to let the bur cut the dentin up to the point of canal division [Figure 2]e. With the same bur, conventional access cavity was prepared for right lateral incisor. The pulp chamber was copiously irrigated with 3% sodium hypochlorite. K-file no. 10 (Dentsply Maillefer, Ballaigues, Switzerland) was used to obtain patency of the canal. Working length was determined and canal was instrumented to size of 30 K-file. A second CBCT scanning was done to compare with preoperative image. The canal was filled with calcium hydroxide paste (UltraCal; Ultradent Products Inc.). Moreover, the access cavity was filled with temporary filling material (Cavit™, 3M ESPE). After 1 week, the patient was asymptomatic and obturation was performed using lateral compaction technique using Sealapex sealer (SybronEndo, The Netherlands).

Case #3: Surgical template-guided hemisection

A 35-year-old male patient with no significant medical history reported pain in the mandibular right first molar. On clinical examination, extensive subgingival caries involving distolingual aspect of crown was noted. The tooth was tender to percussion and did not respond to thermal tests. IOPA demonstrated periapical lesion with evident distal root shortening and external resorption [Figure 2]h. The patient was explained regarding prognosis and was suggested treatment alternatives. The patient insisted on saving tooth and was advised hemisection. CBCT scanning was performed to fabricate template to provide guide for sectioning in the furcation area [Figure 2]i. Conventional two-visit root canal treatment was planned for the mesial root, and distal root canal orifice was closed with glass-ionomer cement (GC Fuji II, America Inc.). After obturation and composite core buildup (3M™ Filtek™ Z350), alginate (3M ESPE) impression was taken and model poured.

After tooth CBCT and cast scan data were uploaded into surgical planning software [Figure 2]j. Template was designed with the buccal and lingual flange that extended till the furcation, i.e. 11.5 mm [Figure 2]k. A groove was incorporated in both flanges corresponding to the bur dimension and to guide the sectioning plane.

The patient was anesthetized with 2% lidocaine (Xylocaine® Dentsply Maillefer) with 1:80,000 epinephrine and mucogingival flap elevated. The template was placed on the tooth. Tapered fissure bur (SS White, New Jersey) was aligned with the template and sectioning was performed [Figure 2]l. IOPA was taken to verify the sectioning followed by removal of distal tooth fragment [Figure 2]m. Flap was repositioned and sutured.


  Discussion Top


CBCT by providing 3D image enhances the visualization of complex root canal anatomies and with the indigenous software helps to analyze different factors affecting the treatment decision-making. The use of CBCT and 3D printing forms the basis for microguided endodontics.[7] Each endodontic case has to be assessed as per the Endodontic Case Difficulty Assessment Guidelines from the American Association of Endodontists, and these three cases reported here can be considered of being high difficulty.[8]

The case of dens invaginatus reported here can be more properly termed dilated composite odontome. This is because of the case presentation which revealed enamel-lined large cavity on the root which was difficult to clean and fill through conventional means. CBCT has been considered a valuable tool for diagnosis and treatment planning for dens in dente.[9] Kfir et al. utilized 3D model of dens invaginatus to plan the correct direction of access channel and to perform treatment modalities on the model before performing actual procedure on the patient, thus avoiding the complications. The 3D model of dens in dente obtained in this study provided valuable information regarding the size of the sac and external irregular surface which was not very well appreciated in CBCT. Since there was no history of trauma, it was assumed that accumulation of necrotic tissue and bacterial ingress into the dens in dente due to periodontal attachment loss may have led to pulpal necrosis resulting in open apex.

The treatment modalities for dens in dente are to treat the invagination as separate canal with or without treatment of the main canal, surgical endodontic treatment, or extraction.[10] Since the defect was large in our case as evident by 3D model, periapical surgical treatment was planned.

The enamel lined cavity was obliterated on the labial and mesial side to obtain better removal of necrotic tissue and to fill the defect with Biodentine to enable better periodontal attachment. The postoperative CBCT after 6 months revealed integration of periodontal architecture and reduction of periapical lesion.

There have been case reports of guided access preparation in the literature performed in anterior teeth for pulp canal obliteration,[11] dens in dente,[12] and dens evaginatus[13] and to obtain minimally invasive access preparation in lower incisors.[14] Limitations of guided endodontics include limited accessibility in posterior teeth, possible dentinal crack formation, and temperature increase.[4],[14] The decision to perform guided access preparation for mandibular incisor was based on the fact that conventional access preparation may have led to indiscriminate tooth structure removal, risk of perforation, and time-consuming.[14],[15] Since incisal attrition was noted, access cavity preparation was performed from the incisal aspect rather than conventional lingual access which allowed straight-line access to the root canals and conserved the tooth structure. Instead of specially adapted bur, conventional long taper crown cutting bur was employed since the objective was to allow preparation up to canal bifurcation rather than preparation to apical third in case of calcified canal.

Connert et al. (2019) in a laboratory study compared conventional access preparation with guided preparation. They reported four times more substance loss, more time taken, and 41.7% of cases canal location with conventional access preparation compared to 91.7% of canal location in guided preparation. The guided access preparation should be used with caution in severely curved canals, teeth with radicular grooves, oval roots, and isthmuses.

The use of guided template for hemisection has for the first time reported in this case report. The guide allowed precise angulation of bur and minimized excessive removal/weakening of tooth structure on the retained fragment. Enough tooth structure remained to support fixed prosthesis, and better periodontal health was obtained.


  Conclusion Top


The combined use of CBCT and 3D printing enabled visualization of complex root canal anatomies and allowed precise and accurate treatment. Although incorporation of these technologies may increase the cost of the treatment, they better maintain the tooth structure integrity and reduce treatment-related complications and time taken to perform the treatment.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Bender IB, Seltzer S. Roentgenographic and direct observation of experimental lesions in bone: I. 1961. J Endod 2003;29:702-6.  Back to cited text no. 1
    
2.
Patel S, Brown J, Pimentel T, Kelly RD, Abella F, Durack C. Cone beam computed tomography in endodontics-A review of the literature. Int Endod J 2019;52:1138-52.  Back to cited text no. 2
    
3.
Estrela C, Bueno MR, Leles CR, Azevedo B, Azevedo JR. Accuracy of cone beam computed tomography and panoramic and periapical radiography for detection of apical periodontitis. J Endod 2008;34:273-9.  Back to cited text no. 3
    
4.
van der Meer WJ, Vissink A, Ng YL, Gulabivala K. 3D computer aided treatment planning in endodontics. J Dent 2016;45:67-72.  Back to cited text no. 4
    
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Kim GB, Lee S, Kim H, Yang DH, Kim YH, Kyung YS, et al. Three-dimensional printing: Basic principles and applications in medicine and radiology. Korean J Radiol 2016;17:182-97.  Back to cited text no. 5
    
6.
Anderson J, Wealleans J, Ray J. Endodontic applications of 3D printing. Int Endod J 2018;51:1005-18.  Back to cited text no. 6
    
7.
Todd R. Cone beam computed tomography updated technology for endodontic diagnosis. Dent Clin North Am 2014;58:523-43.  Back to cited text no. 7
    
8.
American Association of Endodontists Endodontic Case Difficulty Assessment and Referral; 2005. Available from: https://www.aae.org/specialty/wp content/uploads/sites/2/2017/07/ss05ecfe.pdf. [Last accessed on 2021 sep 23].  Back to cited text no. 8
    
9.
Kfir A, Telishevsky-Strauss Y, Leitner A, Metzger Z. The diagnosis and conservative treatment of a complex type 3 dens invaginatus using cone beam computed tomography (CBCT) and 3D plastic models. Int Endod J 2013;46:275-88.  Back to cited text no. 9
    
10.
McClammy TV. Endodontic applications of cone beam computed tomography. Dent Clin North Am 2014;58:545-59.  Back to cited text no. 10
    
11.
Krastl G, Zehnder MS, Connert T, Weiger R, Kühl S. Guided endodontics: A novel treatment approach for teeth with pulp canal calcification and apical pathology. Dent Traumatol 2016;32:240-6.  Back to cited text no. 11
    
12.
Ali A, Arslan H. Guided endodontics: A case report of maxillary lateral incisors with multiple dens invaginatus. Restor Dent Endod 2019;44:e38.  Back to cited text no. 12
    
13.
Mena-Álvarez J, Rico-Romano C, Lobo-Galindo AB, Zubizarreta-Macho Á. Endodontic treatment of dens evaginatus by performing a splint guided access cavity. J Esthet Restor Dent 2017;29:396-402.  Back to cited text no. 13
    
14.
Connert T, Zehnder MS, Amato M, Weiger R, Kühl S, Krastl G. Microguided endodontics: A method to achieve minimally invasive access cavity preparation and root canal location in mandibular incisors using a novel computer-guided technique. Int Endod J 2018;51:247-55.  Back to cited text no. 14
    
15.
Connert T, Krug R, Eggmann F, Emsermann I, ElAyouti A, Weiger R, et al. Guided endodontics versus conventional access cavity preparation: A comparative study on substance loss using 3-dimensional-printed teeth. J Endod 2019;45:327-31.  Back to cited text no. 15
    


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