Related Experiment Video
Updated: Feb 6, 2026

Guided Endodontics: Three-Dimensional Planning and Template-Aided Preparation of Endodontic Access Cavities
Published on: May 24, 2022
Impacts of Contracted Endodontic Cavities on Primary Root Canal Curvature Parameters in Mandibular Molars
Melissa A Marchesan1, Adam Lloyd1, David J Clement2
1Department of Endodontics, University of Tennessee Health Science Center, College of Dentistry, Memphis, Tennessee.
Introduction:
The purpose of this study was to provide information regarding the debate on contracted endodontic cavities (CECs); their impacts on angle, location, and radius of the primary canal curvature (PCC) were assessed in type IV mesial root canals of mandibular molars at different stages of instrumentation. Impacts on treatment time were also assessed.
Methods:
Twenty-four teeth were matched by radiographic and micro-computed tomographic criteria and accessed via CECs (CEC, n = 12) or nonextended traditional endodontic cavities (TECs, n = 12). PCC parameters were radiographically determined using a repositioning apparatus before glide path preparation (PI), after glide path preparation, and after final instrumentation (FI). Instrumentation was performed with PathFiles (13/.02, 16/.02; Dentsply Maillefer, Ballaigues, Switzerland) and ProFile Vortex files (Dentsply Tulsa Dental Specialties, Tulsa, OK) to size 30/.04 at the working length under copious irrigation. Changes in PCC were measured with ImageJ (National Institutes of Health, Bethesda, MD). The instrumentation time was recorded. Data were analyzed with 2-way repeated measures analysis of variance (α < .05) and Tukey honest significant difference tests.
Results:
A significant (P < .001) decrease in the mean angle and increase in the mean radius were detected at each instrumentation stage for both CECs (angle: PI = 42.57°± 8.00°, FI = 32.61°± 5.17°; radius: PI = 6.48 ± 1.81 mm, FI = 10.55 ± 1.48 mm) and TECs (angle: PI = 38.80°± 7.15°, FI = 30.08°± 6.99°; radius: PI = 6.97 ± 2.31 mm, FI = 11.01 ± 2.20 mm). PCC location shifted apically (P < .001). Changes in PCC parameters did not differ significantly between CECs and TECs (P > .05). The treatment time was significantly (P < .0001) longer for CECs (83.17 ± 6.71 minutes) than for TECs (33.18 ± 9.20 minutes).
Conclusions:
Instrumentation of curved mesial canals reduced the severity and abruptness of PCC and shifted the PCC location apically similarly in mandibular molars with CECs and those with nonextended TECs. The extended treatment time with CEC merits consideration when debating CECs versus TECs.
Related Concept Videos
Primary and Secondary Growth in Roots and Shoots
Molar Mass
Degree of Curvature and Radius of Curvature
Applications of the Ideal Gas Law: Molar Mass, Density, and Volume
Oral Cavity
Teeth: The teeth are the hardest structures in our bodies. Humans have two sets of teeth throughout their lifetime: deciduous (baby) teeth and permanent teeth. Each tooth consists of several parts: the crown (visible part), the root (embedded in the jaw), enamel (hard outer...
Vertebral Column: Regions and Curvature
Regions of the Vertebral Column
In an adult, the spine is subdivided into five regions: the cervical, the thoracic, the lumbar, the sacral, and the coccygeal region. The spine initially develops as a series of 33 vertebrae; after 20 years of age, the nine bones in the sacral region, five sacral, and four coccygeal bones fuse to form...

