ABSTRACT
Maxillary incisor fracture is a common dental injury. It is frequently treated by endodontic therapy, orthodontic extrusion, and a retention period. The aim of the study was to mimic this regime and stereologically quantify the vascular and neural reconstitution of the periodontal ligament (PDL). Ten marmosets (Callithrix jacchus) had the right maxillary incisor crown removed, root canal treatment, and magnetic incisor root extrusion of 1.2 mm. After incisor retention for 9 weeks, the animals were perfusion fixed for electron microscopy. The incisor PDL was sectioned at 250 micron intervals from the cervical to apical region and recorded for stereological evaluation. Further evaluations were conducted with a two-way analysis of covariance using program 3V of the BMDP-81 statistical software package. The total luminal PDL vascular volume was statistically unchanged. An increased occurred in the mean number of venous capillaries from 0.07 +/- 0.3 to 0.17 +/- 0.3 per 560 microns 2 of PDL (P < 0.05). Vessel wall and luminal volume of post-capillary-sized venules decreased from 1.64 to 1.03 per cent, and 5.32 to 3.04 per cent (P < 0.05), respectively. Mean luminal and abluminal diameters for post-capillary-sized venules were reduced (P < 0.05). Myelinated and unmyelinated axons showed no significant change in volume (Vv), length (Lv), or surface (Sv) densities. Axon number/unit, PDL area, and mean diameters demonstrated no statistical differences. Since the PDL demonstrated almost complete morphological re-establishment of the microvascular and axon systems, it is considered that this clinical treatment is a justifiable rationale.
