Vui Leng Tan1, Alice Andrawos2, Mounir N Ghabriel2, Grant C Townsend3. 1. School of Dentistry, The University of Adelaide, Adelaide, SA, Australia. 2. Discipline of Anatomy and Pathology, The University of Adelaide, Adelaide, SA, Australia. 3. School of Dentistry, The University of Adelaide, Adelaide, SA, Australia. Electronic address: grant.townsend@adelaide.edu.au.
Abstract
OBJECTIVES: (1) to classify the external morphology of the lingual nerve and investigate any relationship between its external and internal morphology, (2) to explore the fascicular structure, nerve tissue density and capillary density of the lingual nerve, and (3) to provide an anatomical explanation as to why adverse clinical outcomes more commonly affect the lingual nerve following local dental anaesthesia. Where possible, comparisons were made between the lingual and inferior alveolar nerves. MATERIALS AND METHODS: The lingual and inferior alveolar nerves were examined in 23 hemi-sectioned heads macroscopically and microscopically 2mm above the lingula. The lingual nerve was also examined in the regions of the third and second molars. Specimens underwent histological processing and staining with Haematoxylin & Eosin, Masson's Trichrome, anti-GLUT-1 and anti-CD 34. RESULTS: The lingual nerve became flatter as it traversed through the pterygomandibular space. There was an increase in the connective tissue and a decrease in nerve tissue density along the lingual nerve (p<0.001). At 2mm above the lingula, the lingual nerve was uni-fascicular in 39% of cases, whilst the inferior alveolar nerve consistently had more fascicles (p<0.001). The lingual nerve fascicles had thicker perineurium but the endoneurial vascular density was not significantly different in the two nerves. CONCLUSIONS: The greater susceptibility of lingual nerve dysfunction during inferior alveolar nerve blocks may be due to its uni-fascicular structure and the thicker perineurium, leading to increased endoneurial pressure and involvement of all axons if oedema or haemorrhage occurs due to trauma.
OBJECTIVES: (1) to classify the external morphology of the lingual nerve and investigate any relationship between its external and internal morphology, (2) to explore the fascicular structure, nerve tissue density and capillary density of the lingual nerve, and (3) to provide an anatomical explanation as to why adverse clinical outcomes more commonly affect the lingual nerve following local dental anaesthesia. Where possible, comparisons were made between the lingual and inferior alveolar nerves. MATERIALS AND METHODS: The lingual and inferior alveolar nerves were examined in 23 hemi-sectioned heads macroscopically and microscopically 2mm above the lingula. The lingual nerve was also examined in the regions of the third and second molars. Specimens underwent histological processing and staining with Haematoxylin & Eosin, Masson's Trichrome, anti-GLUT-1 and anti-CD 34. RESULTS: The lingual nerve became flatter as it traversed through the pterygomandibular space. There was an increase in the connective tissue and a decrease in nerve tissue density along the lingual nerve (p<0.001). At 2mm above the lingula, the lingual nerve was uni-fascicular in 39% of cases, whilst the inferior alveolar nerve consistently had more fascicles (p<0.001). The lingual nerve fascicles had thicker perineurium but the endoneurial vascular density was not significantly different in the two nerves. CONCLUSIONS: The greater susceptibility of lingual nerve dysfunction during inferior alveolar nerve blocks may be due to its uni-fascicular structure and the thicker perineurium, leading to increased endoneurial pressure and involvement of all axons if oedema or haemorrhage occurs due to trauma.
Authors: Luane Macêdo de Sousa; Assis Felipe Medeiros Albuquerque; Paulo Goberlânio Barros Silva; Thâmara Manoela Marinho Bezerra; Ealber Carvalho Macedo Luna; Filipe Nobre Chaves; Francisco Samuel Rodrigues Carvalho; Karuza Maria Alves Pereira; Ana Paula Negreiros Nunes Alves; Thyciana Rodrigues Ribeiro; Fábio Wildson Gurgel Costa Journal: Case Rep Dent Date: 2015-05-11