ルートカバレッジの事前判定

Predetermination of root coverage.

抄録

背景:

最近、手術で達成可能な最大根面被覆レベル（MRC）を事前に決定する方法が発表された。本研究では、このような方法の予測可能性を、事前に決定されたMRCと、根面被覆手術によって効果的に達成されるMRCを比較することによって評価する。

BACKGROUND: A method to predetermine the maximum root coverage level (MRC) achievable with surgery was recently presented. The present study evaluates the predictability of such a method by comparing the predetermined MRC with that effectively achieved by means of root coverage surgical procedures.

方法:

単一および複数の後退欠損を有する患者 50 例を登録した。MRCは，独立した歯周病専門医が理想的な歯間乳頭の高さを評価し，事前に決定した．ステントの先端基準点（StRP）からMRCまでの距離は，根管治療手術の7日前に測定した．Miller Class I，II，IIIの計135本の歯肉退縮をcoronally advanced flap（CAF）またはsubepithelial connective tissue graft（SCTG）にて治療した．術後15日、30日、90日に独立した歯周病専門医により、StRPと歯肉縁（GM）の距離が測定された。

METHODS: A total of 50 patients with single and multiple recession defects were enrolled. MRC was predetermined by an independent periodontist by assessing the ideal height of the interdental papilla. The distance from the apical reference point of a stent (StRP) and the MRC was measured 7 days before root coverage surgery. A total of 135 Miller Class I, II, and III gingival recessions were treated with the coronally advanced flap (CAF) or with the subepithelial connective tissue graft (SCTG). The distance from StRP and the gingival margin (GM) was measured by another independent periodontist 15, 30, and 90 days after surgery.

結果:

治療した135箇所の歯肉退縮のうち97箇所（71.8％）で、StRP-MRC距離はStRP-GM距離と正確に一致した。上顎と下顎の歯肉溝，CAFとSCTGで治療した歯肉欠損の間では，正確に事前決定された症例に統計的有意差は認められなかった．術前に測定したStRP-MRC距離は，術後90日目に測定したStRP-GM距離よりも，後退欠損24例（17.7％）で大きく，歯肉退縮14例（10.3％）で小さいことが示された．SCTG群ではCAF群に比べ，歯根被覆率の過小評価例が多く，過大評価例が少なかった．その差は統計学的に有意であった（P <0.01）。

RESULTS: In 97 (71.8%) of 135 treated gingival recessions, the StRP-MRC distance coincided exactly with the StRP-GM distance. No statistically significant difference was demonstrated in the cases with exact predetermination between gingival recessions belonging to the maxilla or mandible and between gingival defects treated with CAF or SCTG. The StRP-MRC distance measured before surgery was greater in 24 recession defects (17.7%) and lower in 14 gingival recessions (10.3%) than the StRP-GM distance measured 90 days after surgery. More cases of underestimation and fewer cases with overestimation of the level of root coverage were found in the SCTG group compared to the CAF group. The difference was statistically significant (P <0.01).

結論:

採用した方法は，根管治療術後90日目の軟組織マージンの位置の事前判定に有効であった．また，根面被覆率が過小評価された症例は，臨床的・審美的に成功したと考えるべきであろう．

CONCLUSIONS: The adopted method was effective in predetermining the position of the soft tissue margin 90 days after root coverage surgery. The cases with underestimation of the level of root coverage should be considered clinically and esthetically successful.