Human odontoblast cell numbers after dental injury

Objectives: The purpose of this study was to measure the changes in odontoblast cell numbers in response to cavity restoration variables and patient factors, and the effect these factors have on dental repair by tertiary dentinogenesis. The number of vital odontoblasts is a critical factor for pulpal repair following restorative surgery, and yet little information is available on these cell numbers. Methods: Class V non-exposed cavities were prepared in the buccal surface of intact first or second premolar teeth of 27 patients, between 9 and 17 years of age. Following tooth extraction (28–163 days) the area of reactionary dentine and the area of the odontoblasts were measured histomorphometrically. Results: Patient factors, as well as cavity preparation and restoration variables, had little effect on the numbers of odontoblasts per pulpal unit area. However, the age of the patient did appear to have an effect on the reactionary dentine secretory capacity of odontoblasts per unit area, and on the relative number of odontoblasts beneath cut dentinal tubules. Conclusions: Odontoblast cell numbers were maintained following the preparation of cavities cut into dentine with a 0.5 mm residual dentine thickness. The repair capacity of the pulp–dentine complex would appear to be age dependent, this may explain differences in the success of various restorative treatments between patients.