CBCT-Guided Endodontics: Case report with Dr Thibaut Merit

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Clinical Case Report

CBCT-Guided Endodontics: Lateral Canal Identification and Targeted Disinfection in a Complex Molar

Case byDr. Thibaut Merit — Dublin Endodontics

ToothUR6

Key findingLateral Canal & Furcal Lesion

ModalityCBCT-Guided Endodontics

Dr. Thibaut Merit

Dublin Endodontics · Specialist Endodontist · Toothsaver Faculty

1 Pre-operative Assessment

Periapical Radiograph: Ambiguous Pathology

On two-dimensional assessment of the UR6, the radiographic picture is equivocal. There is a suggestion of periapical change, but the exact location, extent, and aetiology of the pathology — and critically, the source of infection — cannot be determined with confidence from the periapical image alone.

This is a recognised limitation of conventional periapical radiography in endodontic diagnosis. Superimposition of anatomical structures, the inherent two-dimensionality of the image, and the inability to visualise the bucco-lingual extent of lesions all contribute to diagnostic uncertainty in complex cases. The AAE and AAOMR position statement on CBCT in endodontics directly addresses this limitation.

Pre-operative periapical radiograph of upper molar showing treated root canal system with ambiguous periapical pathology — **Fig. 1 — Pre-operative periapical radiograph.** Treated upper molar. Periapical change is suspected on the MB root but the source and extent of pathology cannot be definitively characterised on 2D imaging alone.

AAE / AAOMR Guideline Reference

The AAE and AAOMR (2015) Joint Position Statement on the use of Cone Beam Computed Tomography in Endodontics states: "CBCT should be considered when the diagnosis of apical periodontitis or root resorption is uncertain after conventional radiographic examination."

Furthermore, the position statement supports the use of CBCT where accurate assessment of root and canal morphology is necessary for treatment planning, particularly when conventional imaging does not adequately explain complex anatomy or suspected pathology.

Reference: AAE/AAOMR Joint Position Statement — Use of Cone Beam Computed Tomography in Endodontics (2015 Update). J Endod. 2015;41(9):1393–1396.

→ Digital Radiograph Sensor (KP) → Vatech CBCT Smart X / Green X → Woodpecker Digital Sensor

2 CBCT Analysis

Three-Dimensional Assessment: Lateral Canal and Furcal Lesion Identified

CBCT acquisition transforms the diagnostic picture. Multi-planar reconstruction reveals what the periapical radiograph could not: a lateral canal arising from the palatal root, and a substantial lesion centred in the furcal area. The three-dimensional extent of the lesion — including its bucco-lingual dimension — is now fully characterised.

This finding has direct consequences for treatment planning. The lateral canal represents a pathway of communication between the infected root canal system and the periradicular tissues, explaining the furcal bone destruction. Without CBCT, this microanatomy would be much harder to localise, and the disinfection protocol may not have been directed as precisely.

CBCT multi-planar reconstruction showing lateral canal in palatal root and large furcal lesion, case by Dr Thibaut Merit, Dublin Endodontics — **Fig. 2 — CBCT multi-planar reconstruction.** Case: Dr. Thibaut Merit, Dublin Endodontics. Sagittal, coronal, and axial views confirm a lateral canal in the palatal root and a large furcal area lesion. The bucco-lingual extent of the lesion is clearly visible — information absent from the 2D periapical film.

Clinical significance: This case demonstrates a core principle of CBCT-guided endodontics — the three-dimensional dataset can provide information that conventional radiography cannot show clearly. In this case, CBCT helped identify the furcal lesion and lateral canal, allowing the clinician to target the suspected source of infection more precisely.

Armed with this three-dimensional map, the clinician can practise guided endodontics: the disinfection protocol is directed specifically to the lateral canal and furcal area, ultrasonic activation is prioritised at the level of the lateral canal orifice, and the access cavity design is informed by the known root and canal morphology rather than anatomical assumption alone.

→ Vatech CBCT Smart X / Green X → KP Digital Sensor

3 Canal Negotiation

Lateral Canal Negotiated: CBCT-Guided Scouting and Microanatomy Access

The working length radiograph confirms successful negotiation of the lateral canal identified on CBCT. This is the clinical translation of the three-dimensional diagnosis: the clinician uses the CBCT dataset as a roadmap to direct scouting files precisely to the microanatomy, rather than relying on tactile feedback alone in an anatomically ambiguous field.

Negotiation of lateral canals of this nature requires dedicated scouting technique. Size 08 and 10 hand files, such as D-Finders or equivalent instruments, are used with a watch-winding, short-amplitude motion to explore the canal space without ledging or transporting the lateral canal orifice. Pre-curving of the apical 1-2mm with an endo bender or endo pliers is important when approaching an acutely angled lateral canal. Once engaged in the lateral anatomy a 10:1 reciprocating handpiece can be attached. This skill-intensive manoeuvre is taught in the Toothsaver negotiation course with Dr. Thibaut Merit.

Working length radiograph confirming lateral canal negotiation with files placed in palatal root lateral canal, case by Dr Thibaut Merit, Dublin Endodontics — **Fig. 3 — Working length radiograph.** Case: Dr. Thibaut Merit, Dublin Endodontics. Files placed confirming successful negotiation of the lateral canal in the palatal root. CBCT pre-operative planning permitted targeted scouting to this microanatomy.

Technique note: In cases of this complexity, minimally invasive access cavity design remains a priority — preserving pericervical dentine and maintaining structural integrity while still achieving the necessary visual and instrument access to relevant canal anatomy.

Following negotiation, the disinfection protocol is directed and sequenced according to the CBCT anatomy. Sodium hypochlorite delivers the primary antimicrobial action, with ultrasonic activation used to encourage irrigant penetration into the lateral canal and furcal communication. Dual Rinse HEDP/EDTA can be used as a chelating adjunct with Dual rinse designed for compatibility with sodium hypochlorite. In cases with lateral canal or furcal involvement, irrigant selection and activation should be carried out carefully.

→ D-Finders Hand Files (08/10) → Toothsaver Assorted Files → Sodium Hypochlorite → Dual Rinse HEDP → Ultrasonic Activation Tips → Endo 3 Wireless Ultrasonic → D600 Premium Ultrasonic → Woodpecker AI Motor Black → Endo GT Motor

Learn this technique: Canal Negotiation with Dr. Thibaut Merit

The scouting and lateral canal negotiation technique demonstrated in this case is taught in the Toothsaver negotiation course with Dr. Thibaut Merit. The course covers 08/10 finder technique, reciprocating and continuous rotation handpiece use, ultrasonic adjuncts, and disinfection and obturation protocol for complex anatomy cases.

View courses →

4 Case Summary

Summary: The Diagnostic and Therapeutic Value of CBCT in Complex Endodontics

Summary composite: pre-operative radiograph, working radiograph with files, and clinical intra-oral photograph showing minimally invasive access cavity, case by Dr Thibaut Merit, Dublin Endodontics — **Fig. 4 — Case summary composite.** Case: Dr. Thibaut Merit, Dublin Endodontics. Top row: pre-operative and working length radiographs. Bottom row: CBCT view, working radiograph, and clinical photograph demonstrating minimally invasive access cavity design with preservation of tooth structure.

This case demonstrates why CBCT can be a valuable diagnostic tool in complex endodontics. The periapical radiograph, while suggestive of pathology, provided insufficient information to direct treatment confidently. The CBCT revealed the suspected aetiology — a lateral canal in the palatal root communicating with a furcal lesion — and enabled targeted, guided endodontic treatment planning.

The clinical photograph in the summary composite illustrates the minimally invasive access philosophy that underpins the Toothsaver teaching approach. A precisely directed, conservative access cavity preserves the structural integrity of the crown and root dentine while still permitting visualisation and instrumentation of relevant microanatomy.

Teaching philosophy: At Toothsaver, we teach that endodontic excellence is achieved by combining three-dimensional diagnostic insight with minimally invasive technique. CBCT does not replace clinical skill — it informs it.

Following successful negotiation and disinfection of the lateral canal and main canal system, obturation is completed with One-Fil bioceramic sealer — a tricalcium silicate-based material designed for biocompatible sealing. Its flow characteristics may be useful in cases with lateral canal anatomy where obturation of accessory canal space is desired.

Follow-up radiography at 6 and 12 months will be used to assess resolution of the furcal lesion and monitor healing. We look forward to sharing the outcome.

→ One-Fil Bioceramic Sealer → One-Fil PT Bioceramic Putty → Fi-P Down-Pack Obturation Pen → Fi-G Backfill Obturation Gun → Gutta Percha Points

Guideline reference: American Association of Endodontists (AAE) and American Academy of Oral and Maxillofacial Radiology (AAOMR). Joint Position Statement — Use of Cone Beam Computed Tomography in Endodontics: 2015 Update. Journal of Endodontics. 2015;41(9):1393–1396. doi:10.1016/j.joen.2015.04.021

Case attribution: All clinical images courtesy of Dr. Thibaut Merit, Dublin Endodontics. Published with permission.

Disclaimer: This case report is provided for educational purposes for qualified dental professionals and does not constitute specific clinical advice. Patient images contain no identifiable information.