加齢に伴う歯髄血流振動の線形・非線形解析

Linear and nonlinear analysis of dental pulp blood flow oscillations in ageing.

• B Dzeletovic
• D J Stratimirovic
• D Stojic
• L J Djukic

抄録

AIM:

健康な一般集団を対象に、ウェーブレット解析を用いて加齢が歯髄微小循環の制御機構に及ぼす影響を調査し、血流振動の線形・非線形パラメータを算出することを目的とした。

AIM: To investigate the effect of ageing on control mechanisms of pulpal microcirculation using wavelet analysis and to calculate linear and nonlinear parameters of blood flow oscillations, in a healthy general population.

方法:

レーザードップラーフローメーター（PeriFlux PF 5001、Perimed、Jarfalla、スウェーデン）を使用して、右上顎中切歯の歯髄血流（PBF）振動を、若い参加者10人のグループ（20-25歳）と高齢者10人のグループ（60-70歳）で記録した。合計20回の記録を少なくとも20分間（被験者1人につき1本の歯に1回の記録）取得した。ウェーブレット分光分析を用いて、振幅とパワーを線形として、ハースト指数をPBF振動の非線形パラメータとして計算した。2つのグループ間の差は、独立Student t-検定を用いて評価した。

METHODOLOGY: Pulpal blood flow (PBF) oscillations were recorded on right maxillary central incisors using laser Doppler Flowmeter (PeriFlux PF 5001, Perimed, Jarfalla, Sweden) on a group of 10 young participants (20-25 years) and a group of 10 older adults (60-70 years). In total, 20 recordings were obtained for at least 20 min (one recording on one tooth per subject). Using wavelet spectral analysis, the amplitude and power were calculated as a linear and Hurst exponent as a nonlinear parameter of PBF oscillations. Differences between the two groups were assessed with the independent Student t-test.

結果:

平均PBF値は、若年者よりも高齢者の方が有意に低かった（P=0.024）。筋原性活動（それぞれP=0.046、P<0.001）と神経原性活動（それぞれP=0.04、P=0.01）に対応する相対的な振幅とパワーは有意に高かったが、内皮機能（それぞれP=0.04、P=0.01）に対応する値は、若年参加者よりも高齢者の方が有意に低かった。PBF振動の全スペクトル、筋原性成分、内皮成分のハースト指数（それぞれP<0.001、P=0.02、P<0.001）は、若年者に比べて高齢者で有意に低かった。

RESULTS: Mean PBF levels were significantly lower (P = 0.024) in older adults than in young participants. Relative amplitudes and powers corresponding to the myogenic (P = 0.046, P < 0.001, respectively) and neurogenic activity (P = 0.04, P = 0.01, respectively) were significantly higher, whereas values corresponding to the endothelial function (P = 0.04, P = 0.01, respectively) were significantly lower in older adults than in young participants. Hurst exponents of the total spectrum, myogenic and endothelial component (P < 0.001, P = 0.02, P < 0.001, respectively) of PBF oscillations were significantly lower in older adults in comparison to young participants.

結論:

歯髄微小循環のレベルでは，加齢は血流レベルの変化，血流振動へのさまざまな制御機構の寄与，血管平滑筋と内皮の相互作用と関連していた．このような歯髄血行動態の変化は、生理的行動の理解を深め、病理学的刺激に対する高齢歯髄の適応性の低下に貢献しています。

CONCLUSIONS: At the level of pulpal microcirculation, ageing was associated with altered blood flow levels, the contribution of different control mechanisms to blood flow oscillations as well as the interaction of vascular smooth muscle and endothelium. Described changes of pulpal haemodynamics contribute to a better understanding of physiological behaviour and decreased adaptability of aged dental pulp to pathological stimuli.

© 2020 International Endodontic Journal. Published by John Wiley & Sons Ltd.