Root Apex-Anatomical And Physiological Foramen



Apical constriction (Physiological foramen)

  • is conside­­red narrowest diameter of the root canal

  • located at the cement-dentinal junction.

  • it is the apical limit of root canal preparation preparation.

  • it is also known as the histological foramen, because it is located at the junction between the

  • pulpal connective and interstitial loose connective tissues of the periodontal ligament.

  • not visible on x-ray (we may find it only using WL determination methods).

Apical foramen (Anatomical foramen)

  • Opening at the root surface through which pass nerves and blood vessels.

Between apical constriction and apical foramen, cell-rich connective (periodontal) tissue is found. After proper RCT, this tissue may start the apposition of cementum -like cells to create hard tissue for closure of the root canal apically.

Radiographic apex (Anatomical apex), Radiographic vertex (True apex)

  • highest point of the root seen on X-ray.

  • may correspond to apical foramen or (usually) not.

According to research the average distances are:

  • apical constriction–apical foramen ~0.5-0.8mm.

  • apical foramen–radiographic apex ~0-0.3mm.

  • apical constriction–radiographic apex ~up to 1.1mm.