The goal of this clinical trial is to assess the efficacy and outcome of sealer-based obturation (SBO) using a new calcium silicate sealer in comparison with warm vertical compaction (WVC) using a resin-based sealer, which is the current gold standard.

Calcium silicate sealers are used in endodontics because of their biocompatibility, bioactivity, and their ability to form a hydroxyapatite-mediated interfacial bond with root canal dentine. Although in vitro and retrospective clinical studies have reported promising findings, there remains a lack of prospective, well-controlled trials evaluating their clinical and radiographic performance.

Aims and Objectives:

1. To compare the clinical outcome of single-cone bioceramic obturation (SBO) with warm vertical compaction (WVC) in primary root canal treatment.
2. To compare the radiographic outcome of SBO and WVC using periapical (PA) radiographs and cone-beam computed tomography (CBCT).

Materials and Methods:

Patients referred for primary root canal treatment of molar teeth at Jaber Al-Ahmed Dental Center who fulfil the inclusion and exclusion criteria will be invited to participate. Written informed consent will be obtained from all participants.

Preoperative PA radiographs and CBCT scans will be taken. After completion of root canal instrumentation, participants will be randomly allocated to either Group A: SBO or Group B: WVC. Participants will be blinded to the obturation technique. Allocation will remain concealed until canals are ready for obturation, at which time the treating clinician will be informed of the assigned method.

All teeth will receive definitive restorations following obturation. Participants will be recalled at 12 months for clinical and radiographic evaluation using PA radiographs and CBCT, and will subsequently be followed annually for up to 4 years.

The study will conform to the CONSORT statement and will be conducted in accordance with the Declaration of Helsinki. Ethical approval has been granted by the local health authority (ID: 2291).

Statistical and Analytical Plan:

Sample size estimation for the primary healing outcome was performed using PASS (NCSS, Kaysville, UT, USA). Burns et al. (2022) reported pooled healing rates of approximately 92-93% under loose criteria and 82% under strict criteria in primary NSRCT, indicating that reductions on the order of 10-12 percentage points are clinically meaningful. Based on these data, an absolute 12% difference (0.99 vs 0.87) was considered clinically important.

Using a two-sided test comparing two independent proportions, with 80% power and 5% significance level, detecting this 12% absolute difference required 108 teeth (54 per group). Accounting for a 20% anticipated loss to follow-up, the required sample size is 136 teeth (68 per group).

Healing at 12 months will serve as the dependent variable in logistic regression models. Predictor variables will include age, sex, preoperative status, presence of apical periodontitis, preoperative pain, patency, apical preparation size, root filling quality, and sealer type. Two-way interactions will be assessed. Analyses will follow the intention-to-treat principle.

Null Hypothesis:

H₀: There is no difference between SBO and WVC in clinical or radiographic healing outcomes at 12 months.

Inclusion Criteria:

• Participants must be 18-65 years of age at the time of recruitment
• Participants must have a classification of I or II on the American Society of Anesthesiologists (ASA) physical status classification system
• Participants must not have known allergies to any materials used in the study
• Participants must agree to participate in the study by signing a consent form
• Participants must have good oral hygiene
• Maxillary and mandibular permanent molar teeth that require primary root canal treatment will be included
• The teeth must be restorable and have fully formed roots with no advanced periodontal disease

Exclusion Criteria:

• ASA classification of III or more
• Pregnant or breastfeeding women
• Patients who are unable to give consent
• Patients who have advanced periodontal disease or teeth with more than 5mm probing
• Anterior, premolar and third molar teeth
• Teeth whose apices were over-enlarged at the time of pulp extirpation
• Teeth with broken instruments
• Teeth with blocked or non-negotiable canals
• Teeth with iatrogenic perforations
• Teeth with incomplete root formation
• Teeth with internal or external root resorption
• Teeth that have a poor restorative prognosis
• Teeth that require posts or extensive prosthetic rehabilitation
• Teeth with cracks
• Teeth that have been previously root-filled

Participants will be blinded to the type of treatment they will receive to reduce bias in the reporting of pain.

Since it is not possible to blind the care providers, they will only be informed of the type of treatment once cleaning and shaping has been completed and the tooth is ready to be obturated. This will reduce care provider bias.

Assessors will be blinded to the treatment option to reduce bias during the assessment of healing.