Access cavity preparation is a step of Root Canal Treatment which marks the start of RCT and is one of the most important step as it requires knowledge of location and number of Root Canals present in every tooth, to understand the proper technique and location of starting and preparing the Access Cavity. A Dental Practitioner should be aware that there can be additional nerves or Root canals in every tooth which should be considered before the start of Access Opening with the help of a Diagnostic aid – IOPA, RVG, CBCT, OPG, etc. By determining before hand we can determine the shape and size of the access opening.

In Mandibular Molars there are additional Root canals and Roots known as Radix Entomolaris and Radix Paramolaris, which consist of additional Roots in the Distolingual aspect or the Distobuccal aspects. In such cases the traditional Access opening shape shown in the image below should be altered and the shape changed to gain access to the additional root canal.

Here is the image and the details of the Shapes of Access Cavities of Mandibular Teeth:

  1. Mandibular Central Incisor: Access cavity is Oval in shape with longest diameter inciso-gingivally
  2. Mandibular Lateral Incisor: Access cavity is Oval in shape with longest diameter incisogingivally
  3. Mandibular Canine: Oval shape with greatest diameter Labiopalatally, root canal is narrower in mesio-distal dimension
  4. Mandibular 1st Premolar: Access cavity is Oval in shape and is wider Mesio-distally compared to Maxillary 1st premolar
  5. Mandibular 2nd Premolar: Access cavity is Oval in shape and is wider Mesio-distally
  6. Mandibular 1st Molar: Access cavity is Trapezoidal or Rhomboid in shape, the buccal aspect is wider in comparison to the distal aspect.
  7. Mandibular 2nd Molar: Access cavity is Trapezoidal or Rhomboid in shape, the buccal aspect is wider in comparison to the distal aspect.

One thing should be kept in mind, the image shows the Access cavity shapes of ideal non Carious tooth, but in clinical scenario the patient presents with Caries in various parts of the tooth which should be used as the initial step to start access preparation and shape changed as you proceed. You can have Mesio Occlusal Caries, Disto Occlusal Caries, etc which should be removed and then the shape of the access cavity determined.