Microcirculation changes in gingival tissue after ultrasonic tooth preparation in beagle dog

Abstract: Ultrasonic wave technology is widely used during dental treatments. We previously demonstrated that this method protects the gingival tissue. However, the physiological change on the gingival microvasculature caused by this method remains unclear. Objective: The aim of this study was to investigate the relationship between the morphological and physiological effects on gingival microcirculation when preparing teeth, using the conventional dental turbine or ultrasonic method. Methodology: The lower premolar teeth of beagle dogs were prepared along the gingival margin by using a dental turbine or ultrasonic wave instrument. Gingival vasculature changes were investigated using scanning electron microscopy for corrosion resin casts. Gingival blood flow at the preparation site was determined simultaneously by laser Doppler flowmetry. These assessments were performed immediately (Day 0), at 7 days and 30 days after tooth preparation. Results: At day 0, in the turbine group, blood vessels were destroyed and some resin leaked. Furthermore, gingival blood flow at the site was significantly increased. In contrast, the ultrasonic group demonstrated nearly normal vasculature and gingival blood flow similar to the non-prepared group for 30 days after preparation. No significant alterations occurred in gingival circulation 30 days after either preparation; however, the turbine group revealed obvious morphological changes. Conclusions: Based on multiple approach analyses, this study demonstrated that ultrasonic waves are useful for microvascular protection in tooth preparation. Compared with a dental turbine, ultrasonic wave instruments caused minimal damage to gingival microcirculation. Tooth preparation using ultrasonic wave instruments could be valuable for protecting periodontal tissue

生活習慣病にみられる微小血管変化に関するSEM研究

自然発症2型糖尿病モデルラットを用いて、生活習慣病において全身や口腔の器官にみられる微小循環について形態学的な検討を行った。本糖尿病ラットと対照とした通常ラットの上行大動脈に樹脂を注入し、腎、網膜、舌、口蓋、歯肉、骨髄の腐食血管鋳型を作製した。これらを走査型電子顕微鏡にて観察し、糖尿病モデルと対照とで比較検討した。その結果、歯肉組織中の微小循環系の形態については糖尿病モデルと対照とで明瞭な差異はほとんど認められなかったものの、その他の器官では微小循環系の形態に明らかな違いが観察された。糖尿病によって、全身の器官のみならず口腔の器官にも微小循環系に大きな損傷が生じることが明らかになった。自然発症2型糖尿病モデルラットを用いて、生活習慣病において全身や口腔の器官にみられる微小循環について形態学的な検討を行った。本糖尿病ラットと対照とした通常ラットの上行大動脈に樹脂を注入し、腎、網膜、舌、口蓋、歯肉、骨髄の腐食血管鋳型を作製した。これらを走査型電子顕微鏡にて観察し、糖尿病モデルと対照とで比較検討した。その結果、歯肉組織中の微小循環系の形態については糖尿病モデルと対照とで明瞭な差異はほとんど認められなかったものの、その他の器官では微小循環系の形態に明らかな違いが観察された。糖尿病によって、全身の器官のみならず口腔の器官にも微小循環系に大きな損傷が生じることが明らかになった

Alteration of the redox state with reactive oxygen species for 5-fluorouracil-induced oral mucositis in hamsters.

Oral mucositis is often induced in patients receiving cancer chemotherapy treatment. It has been reported that oral mucositis can reduce quality of life, as well as increasing the incidence of mortality. The participation of reactive oxygen species (ROS) in the pathogenesis of oral mucositis is well known, but no report has actually demonstrated the presence of ROS. Thus, the purpose of this study was thus to demonstrate the involvement of ROS and the alteration of the redox state in oral mucositis using an in vivo L-band electron spin resonance (ESR) technique. An oral mucositis animal model induced by treatment of 5-fluorouracil with 10% acetic acid in hamster cheek pouch was used. Lipid peroxidation was measured as the level of malondialdehyde determined by the thiobarbituric acid reaction. The rate constants of the signal decay of nitroxyl compounds using in vivo L-band ESR were calculated from the signal decay curves. Firstly, we established the oral mucositis animal model induced by treatment of 5-fluorouracil with acetic acid in hamster cheek pouch. An increased level of lipid peroxidation in oral mucositis was found by measuring malondialdehyde using isolated hamster cheek pouch ulcer. In addition, as a result of in vivo L-band ESR measurements using our model animals, the decay rate constants of carbamoyl-PROXYL, which is a reagent for detecting the redox balance in tissue, were decreased. These results suggest that a redox imbalance might occur by excessive generation of ROS at an early stage of oral mucositis and the consumption of large quantities of antioxidants including glutathione in the locality of oral mucositis. These findings support the presence of ROS involved in the pathogenesis of oral mucositis with anti-cancer therapy, and is useful for the development of novel therapies drugs for oral mucositis

Malondialdehyde (MDA) concentration in the isolated cheek pouch with oral mucositis.

<p>MDA concentration was assessed by TBARS assay and normalized by the amount of protein. The data are expressed as mean ± SD in all groups (n = 8–11). Statistical analysis was conducted using Tukey’s method. Experimental conditions are described in <i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0082834#s2" target="_blank">Materials and Methods</a></i>. *<i>P</i><0.05 vs. saline control, †<i>P</i><0.05 vs. 5-FU.</p

Decay rate constant of carbamoyl-PROXYL (C-PROXYL) in hamster cheek pouch.

<p><i>In vivo</i> L-band electron spin resonance spectroscopy was measured at intervals of 15 seconds from 30 seconds after <i>i.v.</i> treatment with C-PROXYL. Results are expressed as mean ± SD in all groups (n = 5–8). Statistical analysis was conducted using Tukey’s method. Experimental conditions are described in <i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0082834#s2" target="_blank">Materials and Methods</a></i>. *<i>P</i><0.05 vs. saline control, †<i>P</i><0.05 vs. 5-FU.</p