The Root Canal Procedure Step by Step: What Happens During Endodontic Treatment product guide

The Root Canal Procedure Step by Step: What Happens During Endodontic Treatment

Most patients arrive at a specialist endodontic practice carrying a version of the same fear: they know they need a root canal, but they have no clear picture of what will actually happen to them in the chair. That uncertainty - more than any specific dread of pain - is often the primary source of anxiety. When you understand precisely what a specialist endodontist does at each stage, and why they do it, the procedure transforms from something vaguely threatening into a logical, highly controlled sequence of clinical steps with a single goal: saving your natural tooth.

This guide provides a detailed, chronological walkthrough of what happens during a root canal appointment at a specialist endodontic practice such as Smile Solutions Melbourne. It covers every stage from the first diagnostic examination through to the placement of a temporary restoration - explaining the clinical rationale behind each step, the sensations you can expect, and how specialist-grade technique and technology make each phase more precise and more comfortable than what was possible even a decade ago.

What Is a Root Canal, Clinically Speaking?

Before the steps, the concept. The goal of root canal therapy (RCT) is to remove infectious agents, cure the disease, and preserve natural teeth. More specifically, a root canal is a procedure that removes infected pulp from inside your tooth, after which the dentist cleans and seals the canals to prevent further damage and save the tooth.

The primary objective of endodontic treatment is to preserve the natural dentition through the prevention and/or treatment of pulpal and periradicular pathosis. Every step in the procedure below serves that objective.

How Long Does a Root Canal Take? A Quick Reference

Before diving into the steps, it helps to anchor your expectations around time. The answer depends primarily on which tooth is being treated and how many canals it contains.

In most cases, a root canal takes 60 to 90 minutes to complete. Some straightforward cases can be completed in a single visit, while more complex situations may require two or more appointments.

For most patients, endodontic treatment requires one to two visits; although endodontists are often able to complete a root canal treatment in a single visit, there are times when anatomy, infections, or calcifications may complicate the procedure, making two appointments necessary.

It is generally expected that a root canal specialist can complete cases more rapidly than a general dentist, especially more difficult or complex ones.

Stage 1: Pre-Treatment Examination and Diagnosis

What the Endodontist Assesses Before Touching the Tooth

The appointment begins before any instrument enters your mouth. At a specialist practice, the diagnostic phase is thorough and methodical - because every subsequent decision depends on an accurate understanding of the tooth's anatomy, the extent of infection, and the case's complexity.

The Australian Society of Endodontology (ASE) identifies diagnosis and case difficulty assessment as a foundational component of the approach a competent practitioner takes before commencing treatment. At Smile Solutions, this assessment incorporates:

• Clinical examination: percussion testing (tapping the tooth), palpation of surrounding gum tissue, probing for periodontal involvement, and pulp vitality testing using cold or electric stimulation
• Periapical radiographs: two-dimensional images taken at different angles to assess root length, canal curvature, periapical bone status, and existing restorations
• Cone Beam CT (CBCT) imaging where indicated: three-dimensional imaging that reveals anatomy invisible on conventional X-rays - extra canals, root fractures, and the precise extent of periapical pathology

With the clinical application of CBCT, clinicians have a better understanding of the anatomy complexity of the root canal system and the technique sensitivity of root canal therapy, which contributes to the efficacy of treatment.

The endodontist will assign a formal diagnosis - for example, symptomatic irreversible pulpitis or pulp necrosis with symptomatic apical periodontitis - and explain the treatment plan, the expected number of appointments, and what you will experience at each stage. (For a full explanation of the symptoms that lead to this appointment, see our guide on Signs You Need a Root Canal: Symptoms, Causes, and When to See a Specialist.)

Stage 2: Local Anaesthesia - Achieving Profound Numbness

What You Will Feel (and What You Won't)

Once the diagnosis is confirmed and treatment is consented, the first clinical act is anaesthesia. This stage is the single most important determinant of patient comfort, and it is where specialist technique diverges most clearly from routine general dental practice.

The endodontist administers a local anaesthetic - most commonly lignocaine (lidocaine) with adrenaline - via inferior alveolar nerve block for lower teeth or infiltration for upper teeth. The injection itself involves a brief sting as the needle enters the soft tissue; the anaesthetic is then deposited slowly to minimise discomfort.

For teeth with hot pulpitis (active, inflamed pulps that are notoriously difficult to numb), a specialist endodontist has access to supplemental techniques including:

• Intraligamentary (periodontal ligament) injection: anaesthetic delivered directly into the space between the tooth root and bone
• Intraosseous injection: anaesthetic delivered directly into the surrounding bone
• Intrapulpal injection: a small volume of anaesthetic deposited directly into the pulp chamber once access is established

Because they are performed under local anaesthesia, root canals are generally no more painful than other routine procedures. The goal at Smile Solutions is complete, verified anaesthesia before any instrumentation begins. (For a comprehensive discussion of pain science and anaesthesia protocols, see our guide on Root Canal Pain and Anaesthesia: Does Root Canal Treatment Hurt in 2025?)

Stage 3: Rubber Dam Placement - Isolating the Operative Field

A Non-Negotiable Safety and Quality Step

Once the tooth is numb, the endodontist places a rubber dam - a thin sheet of latex or latex-free material that isolates the tooth being treated from the rest of the oral cavity.

To keep the area clean and free of saliva, the dentist places a small protective sheet called a dental dam around the tooth, which helps to keep the area isolated and dry throughout the procedure.

The rubber dam serves multiple critical functions:

• Infection control: prevents oral bacteria from contaminating the sterile canal system during treatment
• Airway protection: prevents small instruments, irrigants, and debris from being swallowed or inhaled
• Moisture control: keeps the tooth dry, which is essential for irrigant efficacy and material adhesion
• Visibility: retracts soft tissue and provides a clean operative field

Rubber dam use is a standard of care in specialist endodontics. The ASE's 2024 guidelines for non-surgical root canal treatment in Australia identify isolation as a core competency requirement.

Stage 4: Access Cavity Preparation - Opening the Tooth

Creating the Gateway to the Canal System

With the tooth isolated, the endodontist uses a high-speed dental drill to create an opening through the crown of the tooth - through enamel and dentine - into the pulp chamber below. The dentist or endodontist removes the decay and makes an opening through the crown of the tooth to get to the pulp chamber.

The design of this access cavity is more nuanced than it appears. Modern specialist practice favours a conservative (ninja/truss) access design that preserves as much tooth structure as possible while still allowing straight-line access to all canal orifices. Under the operating microscope - standard equipment at Smile Solutions - the endodontist can precisely locate every canal opening in the pulp chamber floor, including additional canals that are easily missed without magnification.

Over the past two decades, there have been significant advances in technology, materials, and endodontic treatment procedures, including the use of an operating microscope, engine-driven nickel–titanium instruments, ultrasonics, enhanced irrigation technologies, digital radiography, cone-beam computed tomography, and calcium silicate (bioceramic) materials.

You will feel pressure and vibration during this stage but no sharp pain. If you feel anything uncomfortable, alert the endodontist immediately so supplemental anaesthesia can be administered.

Stage 5: Working Length Determination - Mapping the Canal

Precision Measurement Before Instrumentation

Before any shaping begins, the endodontist must determine the precise length of each canal - specifically, the working length, which is the distance from a reference point on the crown to a point 0.5–1.0 mm short of the anatomical apex (root tip).

This is achieved using an electronic apex locator, a device that measures the electrical resistance between the file tip and the periodontal ligament, providing a real-time reading of file position within the canal. This measurement is confirmed with a periapical radiograph.

Specialist practices leverage a computerised drill with an electronic apex locator that gives a precise location for the end of the root, and torque sensing that automatically adjusts the rotation of the super-elastic files to ensure precise, safe, and efficient shaping.

This not only improves the effectiveness of the treatment and improves safety but also significantly reduces the patient's chair time.

Accurate working length determination is non-negotiable: over-instrumentation risks damaging the periapical tissues; under-instrumentation leaves infected tissue in the apical portion of the canal - one of the primary causes of treatment failure. (For more on failure causes, see our guide on Root Canal Retreatment: When and Why a Previous Root Canal Fails and How Specialists Fix It.)

Stage 6: Canal Shaping - Mechanical Debridement with Rotary Files

Removing Infected Tissue and Preparing the Canal for Filling

This is the mechanical heart of the procedure. The endodontist uses a series of nickel-titanium (NiTi) rotary files - flexible, tapered instruments driven by a motor-controlled handpiece - to progressively enlarge and shape each canal from its orifice to its working length.

The goals of shaping are threefold:

1. Debridement: physical removal of infected pulp tissue, bacteria, and necrotic material
2. Shaping: creating a smooth, tapered canal form that allows irrigants to penetrate the full length of the canal and facilitates complete obturation
3. Patency: maintaining the natural curvature of the canal while ensuring the apical foramen remains unblocked

Common endodontic treatment concepts are based on the removal of inflamed or necrotic pulp tissue and the replacement by gutta-percha; however, it is very essential for endodontic treatment to debride the root canal system and prevent the root canal system from bacterial reinfection after root canal therapy.

NiTi rotary files are significantly more flexible than older stainless-steel instruments, allowing them to negotiate curved canals without straightening them - a critical advantage in molars with complex anatomy. The degree of bacterial infection, the root canal anatomy, the instruments chosen, and the treatment techniques employed are closely related to the success of root canal therapy.

During this stage, you will feel vibration and some pressure but no sharp pain. The procedure is systematic: files are used in a sequence from larger to smaller (crown-down technique) or smaller to larger, depending on the protocol, with copious irrigation between each instrument change.

Stage 7: Irrigation and Disinfection - The Chemical Dimension of Cleaning

Why This Stage Is as Important as the Mechanical Shaping

Mechanical shaping alone cannot sterilise a root canal system. The complex internal anatomy of teeth - lateral canals, fins, isthmuses, and dentinal tubules - contains bacteria that files cannot physically reach. Chemical irrigation is what addresses this reality.

Sodium hypochlorite (household bleach) is the most commonly used root canal irrigant; it is an antiseptic and inexpensive lubricant that has been used in dilutions ranging from 0.5% to 5.25%.

NaOCl has excellent antimicrobial capacities and great efficacy in dissolving vital or necrotic tissues, while EDTA is used as an adjuvant to remove the smear layer.

The standard irrigation protocol at a specialist practice involves:

• Sodium hypochlorite (NaOCl): delivered throughout shaping to dissolve organic tissue and kill bacteria
• EDTA (ethylenediaminetetraacetic acid): a chelating agent used in the final irrigation sequence to remove the smear layer - a film of debris that coats the canal walls after instrumentation and can harbour bacteria
• Ultrasonic or sonic activation: agitation of the irrigant using ultrasonic tips or sonic devices to drive the solution into anatomical spaces that passive syringe irrigation cannot reach

Both irrigants showed a considerable antimicrobial effect, but NaOCl achieved a remarkable 96% reduction in bacterial load, compared to CHX's 86%. Recent research published in the Journal of Endodontics (Silva et al., 2025) found that an extended protocol of NaOCl contact time with periodic renewal resulted in a significantly greater microbial reduction compared with standard continuous irrigation.

Crucially, successful endodontic treatment requires debridement of the root canal system through mechanical instrumentation and chemical disinfection followed by sealing with appropriate materials; root canal irrigation is essential since it can clean irregularly shaped canals and isthmuses that are inaccessible by instruments.

Specialist endodontists calibrate their NaOCl concentration carefully. Research published in the International Endodontic Journal (Xu et al., 2022) confirmed that the higher the NaOCl concentration, the greater the effects on dentine structure; endodontists should follow the modern concept of minimally invasive dentistry and avoid using overly high concentration of NaOCl for the sole purpose of more effective disinfection, as this will help prevent root fracture after endodontic treatment.

(For a detailed breakdown of the technology used during irrigation and shaping, see our guide on Root Canal Technology at Smile Solutions: Cone Beam CT, Rotary Instrumentation, and Dental Microscopes.)

Stage 8: Intracanal Medication (If a Second Appointment Is Needed)

When the Endodontist Decides to Defer Obturation

In cases involving severe infection, large periapical abscesses, or persistent bacterial contamination, the endodontist may elect to place an intracanal medicament - most commonly calcium hydroxide (Ca(OH)₂) - and defer the obturation to a second appointment, typically one to four weeks later.

Intracanal medicaments have been used to disinfect root canals between appointments and reduce interappointment pain; the major intracanal medications currently used in endodontics include Ca(OH)₂ and CH.

A temporary restoration is placed to seal the access cavity between appointments. This is not a sign that anything has gone wrong - it is a deliberate clinical decision to optimise the disinfection environment before permanent obturation.

Stage 9: Obturation - Filling and Sealing the Canal System

The Step That Locks in the Result

Once the canals are clean, shaped, and dry, the endodontist obturates - fills and seals - the prepared canal system. The goal is a three-dimensional, hermetic seal that prevents recontamination from residual bacteria and prevents fluid ingress from the coronal direction.

The standard obturation material is gutta-percha - a natural rubber-like material available in standardised tapered cones - used in conjunction with a root canal sealer. Modern specialist practices increasingly use bioceramic (calcium silicate-based) sealers, which offer excellent biocompatibility, dimensional stability, and the ability to bond chemically to dentinal walls.

A correct filling of root canals made with warm gutta-percha technique combined with a bioceramic sealer allows a high success rate in endodontically treated teeth. A 2024 systematic review and meta-analysis by Zamparini et al., published in the International Endodontic Journal, found that included studies differed in terms of clinical protocol and operator expertise, but reported a similar outcome when comparing bioceramic versus standard sealers; tooth survival, treatment outcome, post-operative pain, and periapical extrusion were similar and presented no significant differences between the two sealer types.

Common obturation techniques include:

• Warm vertical compaction (continuous wave): gutta-percha is heated and compacted vertically, flowing into lateral canals and anatomical complexities
• Cold lateral condensation: a master cone is placed to length and accessory cones are compacted laterally alongside it
• Single-cone with bioceramic sealer: a single matched cone is placed to working length with a hydraulic bioceramic sealer filling the remaining space

A post-obturation radiograph is taken immediately to confirm the quality of the fill - verifying that the obturation reaches the correct working length with no voids.

Stage 10: Coronal Restoration - Sealing the Access Cavity

The Final Step in the Chair That Day

The endodontist places a temporary restoration - typically a glass ionomer cement or composite - to seal the access cavity before you leave. This prevents coronal leakage: the ingress of oral bacteria through the crown that can recontaminate the now-clean canal system.

It is recommended that patients contact their dentist to set up an appointment one to two weeks after endodontic treatment is complete, as the tooth may become reinfected or otherwise compromised without a timely restoration.

The temporary restoration is not the final step in your care. Within weeks, you will return to your referring dentist for a permanent restoration - in most cases, a dental crown - which protects the structurally compromised tooth from fracture and ensures long-term survival. (For guidance on this critical phase, see our guide on Root Canal Aftercare: Recovery Timeline, Restrictions, and Long-Term Tooth Survival.)

What You Will Experience During and After the Procedure

Sensations During Treatment

• Pressure and vibration: normal throughout shaping and obturation
• Intermittent sounds: the rotary handpiece and ultrasonic devices produce noise; this is expected
• A sensation of movement: particularly during working length measurement and obturation
• No sharp pain: if you feel sharp pain at any point, raise your hand - the endodontist will administer additional anaesthesia

Post-Procedure Sensations

Some soreness, numbness, or mild discomfort may persist for 24–48 hours after the treatment - which can often be managed by over-the-counter pain medications - but nearly all patients can return to their normal activities the same day.

For a few days, you may notice sensitivity, so it is recommended to avoid chewing directly on the treated tooth until this resolves; after three to seven days, that sensitivity is usually gone.

Key Takeaways

• Root canal treatment is a multi-stage procedure, not a single act. Each stage - diagnosis, anaesthesia, isolation, access, shaping, irrigation, obturation, and temporary restoration - serves a specific clinical purpose and must be executed in sequence.
• Appointment duration varies by tooth type: anterior teeth typically require 45–60 minutes; molars with three or four canals may require 90 minutes or more, sometimes across two visits.
• Irrigation is as important as mechanical shaping. Sodium hypochlorite achieves up to a 96% reduction in bacterial load and dissolves organic tissue that instruments cannot reach; EDTA removes the smear layer to optimise the seal.
• Modern specialist technique is minimally invasive: conservative access cavity design, NiTi rotary files, electronic apex locators, and operating microscopes preserve tooth structure while achieving superior canal cleanliness.
• Obturation is not the end of treatment. A timely permanent restoration - placed by your referring dentist within weeks - is essential to protect the tooth and ensure long-term success.

Conclusion

Understanding the root canal procedure step by step removes the most common source of patient anxiety: the unknown. What you are facing is a logical, well-sequenced clinical protocol, executed by a specialist with years of advanced training, using instruments and materials specifically designed for this purpose. Every stage described above - from the diagnostic examination to the placement of the temporary restoration - exists because it demonstrably improves the outcome for your tooth.

At Smile Solutions Melbourne, Smile Solutions' board-registered specialist endodontists follow contemporary evidence-based protocols aligned with the Australian Society of Endodontology's 2024 guidelines, using the full complement of specialist-grade technology at every stage. If you have been referred for root canal treatment, or are considering seeking specialist assessment, understanding what happens in the chair is the first step toward making a confident, informed decision.

For related guidance, explore our companion articles: Root Canal Pain and Anaesthesia: Does Root Canal Treatment Hurt in 2025?, Root Canal Technology at Smile Solutions, and Root Canal Aftercare: Recovery Timeline, Restrictions, and Long-Term Tooth Survival.

Smile Solutions has been providing specialist endodontic care from Melbourne's CBD since 1993. Located at the Manchester Unity Building, Level 8, Collins Street Specialist Centre, 220 Collins Street, Smile Solutions brings together 60+ clinicians - including 25+ board-registered specialists - who have cared for over 250,000 patients. No referral is required to book a specialist appointment. Call 13 13 96 or visit smilesolutions.com.au to arrange your specialist endodontic consultation.

References

• Peters, O.A., et al. "Guidelines for Non-Surgical Root Canal Treatment." Australian Endodontic Journal, Australian Society of Endodontology, 2024. https://onlinelibrary.wiley.com/doi/full/10.1111/aej.12848

• American Association of Endodontists. "Root Canal Irrigants and Disinfectants." Colleagues for Excellence Newsletter, AAE. https://www.aae.org/uploadedfiles/publications_and_research/endodontics_colleagues_for_excellence_newsletter/rootcanalirrigantsdisinfectants.pdf

• Silva, E.J.N.L., et al. "Improved Root Canal Disinfection through Extended Sodium Hypochlorite Exposure and Renewal after Preparation Procedures." Journal of Endodontics, 2025. doi: 10.1016/j.joen.2025.11.023

• Xu, H., et al. "Effects of Concentration of Sodium Hypochlorite as an Endodontic Irrigant on the Mechanical and Structural Properties of Root Dentine: A Laboratory Study." International Endodontic Journal, 2022. https://onlinelibrary.wiley.com/doi/10.1111/iej.13800

• Zamparini, F., et al. "The Efficacy of Premixed Bioceramic Sealers versus Standard Sealers on Root Canal Treatment Outcome, Extrusion Rate and Post-Obturation Pain: A Systematic Review and Meta-Analysis." International Endodontic Journal, 2024. doi: 10.1111/iej.14069

• Pontoriero, D.I.K., et al. "Outcomes of Endodontic-Treated Teeth Obturated with Bioceramic Sealers in Combination with Warm Gutta-Percha Obturation Techniques: A Prospective Clinical Study." Journal of Clinical Medicine, 2023. doi: 10.3390/jcm12082867

• Cai, Y., et al. "Advances in the Role of Sodium Hypochlorite Irrigant in Chemical Preparation of Root Canal Treatment." BioMed Research International, 2023. https://pmc.ncbi.nlm.nih.gov/articles/PMC9859704/

• Prasad, L.K., et al. "Comparative Analysis of Antimicrobial Efficacy of Sodium Hypochlorite and Chlorhexidine as Irrigants in Root Canal Therapy." Journal of Pharmacy and Bioallied Sciences, 2025. https://pmc.ncbi.nlm.nih.gov/articles/PMC12156664/

• American Association of Endodontists. Guide to Clinical Endodontics, 6th ed. Chicago, IL: AAE, 2024.

• Cleveland Clinic. "Root Canal: Procedure and Recovery." Cleveland Clinic Health Library, 2024. https://my.clevelandclinic.org/health/treatments/21759-root-canal