Control of blood circulation in oral tissue

Changes in gingival blood flow during orthodontic treatment

The aim of the study was to investigate the changes in gingival blood flow due to orthodontic forces. Eleven volunteers, with the maxillary canine in an ectopic position were tested. A Laser Doppler Flowmeter (LDF) with a gingival probe was used, registering both the blood flow and temperature of the gingivae. After baseline measurement, a fixed orthodontic appliance was bonded. Measurements were repeated monthly, after activation of the appliance. The study lasted 6 months. The baseline value was 338.7 ± 201.56 P.U. [Perfusion Unit (mean ± S.D.)] which decreased to 218.9 ± 74.83 P.U. (p < 0.05) after two months and the final value of 363.9 ± 194.86 P.U was not significantly different from that initially (p > 0.5). The results showed that application of a force of 75 g resulted in a decrease in gingival blood flow up to 50%, but this returned to previous values after a few months. The study supports this measurement technique as a useful tool for monitoring gingival blood flow in long-term studies as well.

Gingivitis and Periodontitis as Antagonistic Modulators of Gingival Perfusion

BACKGROUND

We explore the possible association between the extent of gingivitis or periodontitis and an index of gingival microvascular perfusion response to compression of alveolar mucosa, called the gingival perfusion index (GIPI).

METHODS

A cross-sectional analytical study was done in a sample of 60 adults, including healthy and non-insulin-dependent diabetic subjects of either gender, with teeth in the anteromandibular sextant with or without gingivitis and with or without periodontitis at the lower-left lateral incisor (LLLI). A sample was selected by convenience non-probability sampling. Gingival perfusion was evaluated at labial LLLI attached gingiva. Two perfusion recordings were done 5 minutes apart, each one consisting of a 40-second control phase, a 22-second compression phase, and a 40-second postcompression phase. LLLI alveolar mucosa was compressed with a wood-mounted cotton swab until reaching about one-fifth of the control perfusion value. GIPI was used as response dependent variable. The gingival index and probing depth were used as measures of the extent of gingivitis and periodontitis, respectively.

RESULTS

By analysis of covariance and multiple regression analysis, it was found that only the probing depth (negatively) and gingival index (positively) predicted GIPI (R(2) adjusted = 0.5194, P <0.0001).

CONCLUSIONS

The data strongly suggest that, at least in the studied sample, gingivitis and periodontitis operate as antagonistic modulators of gingival perfusion. The major practical implication of our findings is that an increase or decrease in this index (GIPI) at a given attached gingiva site could indicate, respectively, the clinical predominance of gingivitis or periodontitis in such a site.

A novel procedure for evaluating gingival perfusion status using laser-Doppler flowmetry

OBJECTIVES

To systematize a procedure that allows one to characterize the perfusion response pattern of attached gingiva to the topical and transitory compression of alveolar mucose, using laser-Doppler flowmetry.

MATERIAL AND METHODS

A cross-sectional study was carried out, in 20 healthy adult subjects of either sex, with teeth in antero-mandibular sextant but without periodontitis at the lower left lateral incisor (LLLI). Sample was selected by convenience non-probability sampling. Gingival perfusion was evaluated at labial LLLI attached gingiva using a specially designed gingival tray. Two perfusion recordings were carried out 5 min. apart, each one consisting of a 40 s control phase, a 22 s compression phase and a 40 s post-compression phase. During compression phase, LLLI alveolar mucose was compressed with a wood-mounted cotton swab until the perfusion decreased to about 1/5 of its control perfusion value.

RESULTS

Integrated primary basal flow (IPBF) during control phase was of 14,210+/-1075 perfusion units (PU), whereas integrated flow during compression phase was of 1651+/-202 PU (p<0.05). After compression was released, integrated total secondary real flow was 13,322+/-1513 PU (p<0.05) which represented a 91.3+/-3.8% of IPBF. Gingival compression propitiated an induced flow debt (IFD) of 6478+/-781 PU, which increased in 980+/-482 PU after compression was released, representing 18% of the IFD (Debt index).

CONCLUSIONS

A hypoaemic response in reaction to topical and transitory LLLI alveolar mucose compression was observed. Debt index and the ITSRF% are reproducible indices of microvascular perfusion response whose validation under pathological circumstances remains to be evaluated.

Erythrocyte velocity in vascular networks of young noninflamed dog gingiva

Measurements of erythrocyte velocity in vascular networks of noninflamed gingiva of deciduous canines of four young dogs were obtained using vital microscopy and high-speed cinephotomicrography. Mean erythrocyte velocity in small gingival vessels was 1.59 +/- 0.29 mm/sec. Differences in erythrocyte velocity of vessels comprising a gingival microcirculation and of vessels within different gingival samples were not significant.

Distributionoof cardiac output to oral tissues in dogs

Isotope fractionation and particle distribution methods were used in conjunction to quantitate blood flow in the oral mucosa, alveolar bone, tongue, masseter muscle, and dental pulp. Infiltration of epinephrine in lidocaine ( Xylocaine) and lidocaine alone and inhalation of 5% CO2 provided experimental conditions to alter flow in some tissues.