Does Malocclusion Alter the Gustatory Function?

Objectives: Malocclusion leads to various oral complications such as masticatory muscle dysfunction, periodontal diseases, and saliva secretion disorders. However, few studies have assessed the relationship between malocclusion and gustatory function. Therefore, this study aimed to investigate the relationship between malocclusion and gustatory function using the two–bottle taste preference test and immunohistological analysis of the taste papillae in rats.
Methods: All animal handling and experimental procedures were approved by the institutional animal care and use committee (0170352A) and performed in accordance with the animal care standards of Tokyo Medical and Dental University (TMDU). Seven–week–old male Wistar rats were divided into a control and an experimental group. All maxillary molars were extracted in the rats of the experimental group at the age of 7 weeks, and a sham operation was performed in the control animals. First, the rats’ taste preference for five basic taste solutions was evaluated in the two groups, and then rats were euthanized at 4 weeks after the procedures. Second, the morphological changes in the fungiform papilla, and the taste buds were analyzed by immunohistochemical staining using anti-cytokeratin 8 antibody. All data were tested by Student’s t–test using the statistical software (R Foundation for Statistical Computing, Vienna, Austria), and differences were considered significant at p < 0.05.
Results: Animals in the experimental group showed significantly fewer fungiform papillae, narrower circumvallate papillae, shallower trench depth, smaller trench area, smaller taste bud area, and fewer taste buds. However, the two–bottle taste preference test revealed no significant differences in all five basic tastes between the control and experiment groups.
Conclusions: The findings of the present study suggest that there is a possibility of a partially synergic relationship between occlusion and gustatory function.