Anatomical Study of the Greater Palatine Artery: Clinical Implications for Palatal Graft Procedures.

摘要

Introduction: The palate is a well-established donor site for obtaining graft tissue in periodontal plastic surgery procedures. However, proximity to the adjacent teeth on the lateral aspect and the greater palatine neurovascular bundle (GPB) on the medial aspect limit the amount of graft tissue that can be obtained from the palate. Previous studies have been concerned with the location of the greater palatine foramen as well as the greater palatine artery (GPA) and have established guidelines on how to estimate the distance between the teeth and the GPB. Traditionally, clinicians follow these guidelines and choose to avoid removing graft tissue in the area close to the GPB out of fear of possible complications such as hemorrhaging and paresthesias.;Objectives: The purpose of the present investigation is to locate the position of the greater palatal artery (GPA) in relation to surrounding anatomical landmarks and determine if the tissue thickness covering the GPA is sufficient to permit gingival grafts to be obtained in the area close to the GPB.;Materials and methods: Cadaver dissections were performed on a total of ten (n=10) cadaver hemifaces of which 7 were partially and 3 were completely edentulous. From the greater palatine foramen to the incisive foramen, the palatal tissues of the cadavers were dissected into vertical slices of 3 mm in width perpendicular to the median palatine raphe using a double bladed scalpel. On each tissue slice, the distance from the epithelial surface to the superior border of the vessel, the diameter of the vessel, the distance from the inferiorborder of the vessel to the palatal bone, the distance from median palatine raphe to the GPA and the distance from teeth or midline of the alveolar crest to the GPA were measured using both a periodontal probe and a digital caliper. The measurements were correlated to each other, the angle of the palatal vault, an estimate of the palatal depth and the head length of the cadavers.;Results: The mean thickness of the tissue above the GPA was 4.30 +/- 1.61 mm with a range of 1.92 -- 8.72 mm. The tissue thickness decreased consistently from the 3rd molar to the canine area with the thickest mean tissue being in the 2nd molar region with 6.25 +/- 1.09 mm and shallowest mean tissue thickness in the region of the lateral incisor with 2.92 +/- 0.46 mm. The mean distance of the GPA from the median palatine raphe is 10.34 +/- 3.41mm ranging from 13.77 +/- 1.67 mm to 6.02 +/- 0.83 mm with the greatest distance being from the 3rd molar region and smallest distance being from the lateral incisor area. No statistically significant correlations were found between the angel of the palatal vault, the estimate of the palatal depth and the head length. A significant correlation (R2=0.92) was found between the total palatal tissue thickness and tissue thickness above the GPA. Discussion: There was adequate gingival tissue above the GPA to harvest tissue for free gingival grafts of 1 - 1.5 mm in thickness in the entire palate. Donor tissue for 1.5 mm thick connective tissue grafts with a 1.5 mm epithelial flap could be obtained opposing the 1st molar and posterior to it staying above the GPA. Donor site for palatal grafts can be extended in a medial and posterior direction.A Formula (Tissue Thickness above the GPA = (Total Thickness of palatal tissue - 0.967) x 0.9) has been derived, which accurately locates the GPA based on the thickness of the palatal tissue. Unique to this study were measurements from the median palatine raphe, which will provide the clinician with a new landmark to more reliably locate the GPA at various locations on the palate.;Conclusion: This descriptive pilot study on human cadavers provides a formula to locate the GPA within the palate using the total palatal tissue thickness and suggests that graft tissue can be harvested from the tissue above the GPA in the entire palate for FGGs and opposing to the 1 st molar and posterior to it for CTGs not exceeding 3 mm in depth.