Morphometry of neural structures in the mouse periodontal ligament mesial to the mandibular first molar

Abstract

The periodontal ligament mesial to the mandibular first molars of three mice was analysed stereologically between the alveolar crest and the tooth apex. Ultrathin tissue sections were collected at statistically predetermined intervals, 50 and 200 microns apart, examined in the TEM and quantified using standard point counting procedures (Gundersen et al. 1988). Findings indude evidence that, in the mouse, some unmyelinated axons arise from myelinated axons and that anatomically discrete arrangements of unmyelinated axons occur in the apericytic wall sections of postcapillary-sized venules. Morphometric data indicate that unmyelinated axons constitute approximately 95 percent of all periodontal axons. The greatest relative proportion of myelinated axons is in the bone third of the ligament, at depths between 600 and 800 microns, where the ratio of unmyelinated to myelinated axons is 5:1.

Keywords

• mouse molar periodontal ligament
• tem. k-cells
• neural ultrastructure
• oxytalan fibres
• receptors
• stereology
• pdl/anatomy/innervation
• myelinated/unmyelinated axons
• oxytalan fibres
• statistics
• mice