Evaluation of Tissue Resistance to Soft Tissue Emphysema (NIDCR 2R44DE012829-02)
Tissue emphysema has been reported in the dental literature. However, there have been no reports studying what air pressure is required to induce the condition on gingival tissue. Objectives: The purpose of this study was to determine the pressure required in palatal gingival tissue to induce emphysema. Methods: Penetration was measured in vitro in fresh porcine tissue by displacing India ink through a 23 gauge butterfly needle into the tissue at 0, 3, 10, 15, 20 and 25 pounds/square inch (psi) of pressure. Penetration of India Ink within the tissue was performed at three different sites for each pressure. Measurement with a micrometer in fractions of a millimeter of tissue penetration was accomplished by one investigator with the use a dissecting microscope at 10x power. Three trials of 60 seconds at each of three sites were conducted. The distance traveled by the ink was recorded as the average of the three trials. Student t statistic with Dunnett's test for multiple comparisons at the 0.05 level was used to determine significance between penetration at 0 psi (control) and the other pressures. Clinical significance was considered to be penetration of more than 3 mm. Results: The mean penetration measurements results were for 0 psi=0.15±0.30, 3psi=0.39±0.16, 10psi=0.60 ±0.08, 15psi=0.90±0.24, 20psi=4.03±0.74, 25 psi≤6millimeters. No significant penetration of India Ink until 15 psi (0.90±0.24 mm, p=0.008) was shown; clinically significant penetration was noted at 20 and 25 psi (4 to 6 mm, p=<0.0001). Conclusions: Within the test system, pressures of 15 psi or less appear unlikely to cause gingival soft tissue emphysema. The use of pressures 15 psi and greater could induce soft tissue emphysema and should be carefully monitored during surgical procedures.