Effect of Manual and Mechanical Glide Path Preparation on Working Length Accuracy.

This study is an in vitro randomized controlled experimental investigation designed to evaluate and compare the accuracy of working length achievement following manual and mechanical glide path preparation techniques during root canal treatment.

A total of 60 extracted single-rooted permanent teeth with intact roots, mature apices, and minimal canal curvature (≤15°) will be selected according to predefined inclusion and exclusion criteria. After disinfection and sterilization, the teeth will be mounted in resin blocks to ensure stability during instrumentation. The samples will then be randomly allocated into two equal groups (n = 30 each) using a computer-generated randomization method.

Standard access cavities will be prepared for all samples. Canal patency and initial working length will be determined using an electronic apex locator and confirmed with digital periapical radiographs. Silicone stoppers will be used to standardize reference points for all measurements.

In Group 1 (manual glide path group), glide path preparation will be performed using a size #10 stainless steel K-file with a watch-winding and gentle filing motion. In Group 2 (mechanical glide path group), glide path preparation will be carried out using rotary PathFile instruments in sequence with an engine-driven handpiece, following the manufacturer's recommendations. All procedures will be performed by a single operator to eliminate operator-related variability.

After completion of glide path preparation and canal shaping, the final working length will be re-determined using the same apex locator and radiographic methods. The difference between the initial and final working lengths will be measured in millimeters for each specimen and recorded as the primary outcome variable.

Statistical analysis will be performed using SPSS software. Descriptive statistics (mean and standard deviation) will be calculated, and inferential analysis will include paired t-tests for within-group comparisons and independent t-tests for between-group comparisons, with a significance level set at p < 0.05.

The results of this study are expected to provide evidence regarding which glide path preparation technique better preserves working length accuracy, thereby assisting clinicians in selecting optimal endodontic instrumentation protocols and improving treatment outcomes.

Inclusion criteria

Extracted permanent single-rooted teeth. Teeth with fully formed mature apices. Teeth with intact roots and no structural defects. Root canals with curvature less than 15 degrees. Teeth with patent canals allowing negotiation with a size #10 K-file.

Exclusion criteria

Teeth with caries, fractures, cracks, or root defects. Teeth with previous endodontic treatment. Teeth showing root resorption or calcified canals. Teeth with unusual root canal anatomy or multiple canals. Teeth with severe canal curvature greater than 15 degrees. Teeth with immature apices or open apices.