Ultrasonography-Derived Elasticity Estimation of Live Porcine Oral Mucosa.

OBJECTIVES: To investigate the biomechanical properties of porcine oral tissues with in vivo ultrasonography and to compare the difference between oral alveolar mucosa and gingival tissue concerning compressional and tensile mechanical strain. MATERIALS AND METHODS: Sinclair minipigs (6 females and 4 males, 6 to 18 months of age) were anesthetized for ultrasonography. In vivo high-frequency tissue harmonic ultrasound (12/24 MHz) cine-loops were obtained while inducing mechanical tissue stress (0 to 1 N). Post-processing strain analysis was performed in a cardiac speckle tracking software (EchoInsight®). Region of interest (ROI) was placed for gingival and alveolar mucosa tissues for longitudinal (compressional) and tensile strain analyses. A calibrated gel pad was employed to determine the absolute force (pressure) for the measured tissue strain response function. The resulting elasticity data was statistically analyzed using custom Matlab scripts. RESULTS: In total, 38 sonography cine-loops around the third premolars were included in the investigation. The longitudinal strain of alveolar mucosa ε AM L was found to be significantly (P < .05) larger than that of gingiva ε G L . Across the measured force range, ε AM L ~ 1.7 × Îµ G L . Significant differences between alveolar mucosa and gingiva tissues were found for all forces. The tensile strain of the alveolar mucosa ε AM T was found to be ~2 × Îµ G T (on the epithelial surface of the gingiva). Both were statistically significantly different for forces exceeding ~0.08 N. At depth, that is, 500 and 1000 µm below the epithelial surface, the gingiva was found to have less ability to stretch contrary to the alveolar mucosa. Gingival tissue at 500 µm depth has significantly less tensile strain than at its surface and more than at 1000 µm depth. In contrast, the tensile strain of alveolar mucosa is largely independent of depth. CONCLUSION: Ultrasonography can reveal significant differences in oral alveolar mucosal and gingival elastic properties, such as compressional and tensile strain. Under minute forces equivalent to 10 to 40 g, these differences can be observed. As dental ultrasound is a chairside, and noninvasive modality, obtaining real-time images might soon find clinical utility as a new diagnostic tool for the objective and quantitative assessment of periodontal and peri-implant soft tissues in clinical and research realms. As ultrasound is a safe modality with no known bioeffects, longitudinal monitoring of areas of concern would be particularly attractive.

Implication for second primary cancer from visible oral and oropharyngeal premalignant lesions in betel-nut chewing related oral cancer.

BACKGROUND: Visible oral and oropharyngeal premalignant lesions may be used to monitor for a second primary oral cancer. To control for bias, we focused on the visible oral and oropharyngeal premalignant lesions of patients with oral cancer with a positive betel-nut chewing habit. Visible oral and oropharyngeal premalignant lesions that can predict second primary oral cancers were studied. METHODS: Nine hundred ninety-seven patients with positive betel-nut chewing habits and oral cancer were enrolled in this retrospective cohort study. We analyzed the relevance of their visible oral and oropharyngeal premalignant lesion incidence and relative clinicopathological variables to the development of a second primary oral cancer. RESULTS: Second primary oral cancer risk was significantly higher in patients with positive visible oral and oropharyngeal premalignant lesions (P < .0001), especially in younger patients (P = .0023; ≤40 years: adjusted odds ratio [OR] 2.66; 40-60 years: adjusted OR 2.61). The heterogeneous leukoplakia was (adjusted OR 2.17) higher than homogeneous leukoplakia. CONCLUSION: The predictive value and practicality of visible oral and oropharyngeal premalignant lesions make it a potentially valuable marker in follow-ups of patients with a positive betel-nut chewing habit with oral cancer, especially young patients with heterogeneous leukoplakia.