A Comparison of Dentin Tubule Occlusion Properties of Dipotassium Oxalate against Potassium Nitrate: An In Vitro Study.

AIM: The aim of this study is to compare the efficacy of dipotassium oxalate and potassium nitrate to occlude dentinal tubules. MATERIALS AND METHODS: This study utilized Parkinson model of longitudinal dentin tubule occluding properties of dentifrices under a 4-day acid challenge. Dentin disks of approximately 1.5 mm thick were sectioned from the crowns of the freshly extracted molars. The disks were randomized into three sets of 15 and treated with dipotassium oxalate, potassium nitrate, or used as a control. The disks were then subjected to a 4-day acid challenge and evaluated by scanning electron microscopy (SEM). RESULTS: On days 1, 2, and 3, dipotassium oxalate showed significant occlusion of dentinal tubules. On day 4, no significant difference was observed between dipotassium oxalate and potassium nitrate. Both test groups showed better occlusion properties in comparison to the control. CONCLUSION: Through the use of a 4-day acid challenge, this study demonstrates that both agents can indeed occlude dentinal tubules. Initially, dipotassium oxalate does occlude dentinal tubules faster than potassium nitrate. However, at the conclusion of the acid challenge, minimal differences were observed in occlusion rate among the two agents. Further studies should be conducted to determine the efficacy of these two agents. CLINICAL SIGNIFICANCE: Both dipotassium oxalate and potassium nitrate can help treat patients with dentinal hypersensitivity.

Melanotic Macule in Conjunction with a Giant Cell Fibroma.

INTRODUCTION: The aim of this study is to describe a case of a melanotic macule found in conjunction with a giant cell fibroma (GCF). For oral pigmented lesions without an identifiable etiologic factor, critical factors in determining the differential diagnosis are clinical history, symmetry, and uniformity of the lesions. Potential differential diagnosis includes racial pigmentation, endocrine disturbance, Peutz-Jeghers syndrome, trauma, hemochromatosis, oral malignant melanoma, or idiopathic etiology and melanotic macules. Melanotic macules are the most common solitary pigmented melanocytic lesions in the oral mucosa, corresponding to 86.1% of melanocytic lesions of the mouth. Giant cell fibromas are reactive connective tissue lesions in the oral cavity. They were first described as a distinct entity in 1974 by Weathers and Callihan and make up around 5 to 10% of all oral mucosa fibrous lesions. They are commonly mistaken for other growths, such as pyogenic granuloma and fibroma, and diagnosis is accurately based on its distinctive histopathology. This article presents the clinicopathologic findings of a 15-year-old Hispanic male presenting for biopsy of a melanotic macule on the mandibular anterior buccal gingiva. Histologic evaluation of the specimen revealed that the lesion also contained a GCF. Pathologic lesions of the mouth should be carefully diagnosed. Conventionally, histologic evaluation is the gold standard to produce a final diagnosis. As evidenced in this article, multiple lesions may exist in a site and may be mistakenly diagnosed as a single entity. CLINICAL SIGNIFICANCE: While each lesion has been reported individually, in reviewing the literature, no cases were reported in which both histopathologic findings of GCF and melanotic macule were present within the same lesion.