[GLP-1 receptor expression in rat major salivary glands and the effects of bilateral maxillary molar extraction on its expression].

Glucagon-like peptide 1 (GLP-1) is the gastrointestinal hormone released from L-cells of the small intestine and promotes insulin secretion by acting on the pancreas islet. GLP-1 receptor (GLP-1R) expression has been detected in many organs that are involved in carbohydrate metabolism, however its expression in the salivary glands, which participate in the first carbohydrate metabolism, has not been clarified yet. Furthermore, it is known that occlusion affects both the morphology and function of the salivary glands. Thus in this study, we focused on the expression of GLP-1R in the major salivary glands, and analyzed the changes of GLP-1R expression under the occlusal changes. Twenty-four male Wistar rats were used in this study. In the experimental group, all maxillary molars were extracted at 7 weeks old. The rats without molar extraction were used as the control group. The rats were sacrificed at 8 and 11 weeks old, then the parotid gland (PG), submandibular gland (SMG), and sublingual gland (SLG) were analyzed immunohistochemically for the presence of GLP-1R. Immunohistochemical staining showed GLP-1R to be localized in the ductal cells of PG, SMG, and SLG. In SLG, there were no differences in the intensity of GLP-1R staining in both the control and experimental groups at 8 and 11 weeks old. In PG and SMG, the intensity of GLP-1R staining in the experimental group was significantly weaker than in the control group at 11 weeks old, otherwise there were no differences at 8 weeks old. In conclusion, GLP-1R is expressed in rat PG, SMG, and SLG, and its expression can be influenced by molar extraction.

Degeneration of fungiform and circumvallate papillae following molar extraction in rats.

OBJECTIVE: Proper occlusion facilitates food intake and gustatory function is indispensable for the enjoyment of food. Although an interaction between dentoalveolar and gustatory afferent neurons has been suggested by previous studies, the relationship between occlusion and gustation remains unclear. This study investigated the effect of upper molar extraction which diminished occlusal support on peripheral gustatory receptors in rats. MATERIALS AND METHODS: Thirty-six 7-week-old male Wistar rats were randomly assigned to either the experimental or the control group. All maxillary molars were extracted from rats in the experimental group under anesthesia, while a sham operation was conducted in the control group. The rats were euthanized 7, 14 or 28 days after the procedure. The morphology of the circumvallate papillae and taste buds using immunohistochemical methods and the fungiform papillae were visualized with 1% methylene blue. RESULTS: Defects in the gustatory epithelium were observed after maxillary molar extraction. Rats in the experimental group had significantly fewer fungiform papillae, narrower circumvallate papillae, shallower trench depth, smaller trench area, smaller taste bud area, lower ratios of taste bud area to trench area and fewer taste buds than those in the control group. CONCLUSIONS: The findings indicate that molar extraction would affect peripheral gustatory receptors. This is the first study to characterize changes in rat fungiform and circumvallate papillae after maxillary molar extraction. This study suggests a possible synergic relationship between dentoalveolar perception and gustatory function, which has clinical implications that occlusion is closely correlated with gustatory perception.

Optimized Periodontal Regeneration for Orthodontics (O-PRO): A Case Series.

The fusion of orthodontic treatment and periodontal tissue-regeneration therapy has attracted attention. However, regenerated bone has a higher density than physiologic bone, which may cause problems including root resorption or stagnation of orthodontic movement. Therefore, the optimized periodontal regeneration for orthodontic movement (O-PRO) approach was developed with the aim of regenerating periodontal tissues with sparse bone quality. Unlike conventional methods, this concept is specifically suited for orthodontic movement. A new classification for the preoperative evaluation of periodontal tissues was also devised, and results are reported from cases where orthodontic treatment was implemented using each type of O-PRO method.