The effects of ageing on the biomechanical properties of root dentine and fracture.
J Dent
; 42(3): 305-11, 2014 Mar.
Article
en En
| MEDLINE
| ID: mdl-24321296
ABSTRACT
OBJECTIVES:
Knowledge of the mechanical behaviour of root dentine can facilitate better understanding of spontaneous vertical root fracture (VRF), an age-related disease initiated mainly at the root apex. We tested the hypothesis that the biomechanical properties of root dentine change with ageing.METHODS:
Sixteen human premolars were divided into "old" (17-30 years) and "young" (50-80 years) groups. The elastic modulus, nano-hardness, micro-hardness, elemental contents, tubular density/area of root dentine in cervical, middle and apical root regions were evaluated using atomic force microscopy-based nano-indentation, Knoop indentation, scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively.RESULTS:
The apical dentine showed a lower nano-hardness, a lower elastic modulus, a lower calcium content, a lower calcium-to-phosphorus ratio and a smaller tubular density/area than the cervical dentine in both age groups, whereas spatial differences in micro-hardness were observed only in old roots. Compared with young dentine, old dentine showed a greater hardness, a higher elastic modulus, a greater mineral content and a smaller tubular size in the cervical portion, whereas the age-induced changes in tubular density were insignificant. Finite element analysis revealed that due to its higher elastic modulus, old apical dentine has a higher stress level than young dentine.CONCLUSIONS:
The intrinsic material properties of root dentine have spatial variations, and they are altered by ageing. The higher stress level in old apical dentine may be one reason, if not the most important one, why spontaneous VRFs are more likely to occur in the elderly population.Palabras clave
Texto completo:
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Base de datos:
MEDLINE
Asunto principal:
Fracturas de los Dientes
/
Raíz del Diente
/
Envejecimiento
/
Dentina
Idioma:
En
Revista:
J Dent
Año:
2014
Tipo del documento:
Article