皆さん、こんにちは。

さて、話もだいぶ進んできまして

Factors affecting the long-term results of endodontic treatment

の結果（後半）になります。

The prognosis was slightly less favorable for roots with　preoperative pulp necrosis and periapical lesions when the　root was restored with a crown or acted as an abutment for　a bridge (p = 0.02 and p = 0.04, respectively). For the　retreatment group, no significant influence on the result of　treatment was found when the teeth were crowned or acted　as abutments. Factors such as age and sex of the patient, presence of deep　periodontal pockets, whether the roots were provided with　posts or not or were used as abutments for partial dentures,　and the number of bacterial sampling done before filling the　root had no influence on the outcome of treatment. Neither　a flare-up occurring during the treatment nor the presence of　an initial acute periapical abscess influenced the result of　treatment. The frequencies of file fractures and perforations to the　periodontal ligament were low. For all examined roots, file　fractures occurred in 11 roots (1.3%) and perforations in 13　roots (1.5 %). Periapical lesions were later noted on two such　roots with file fractures and on three roots with perforations. The stepwise logistic regression analysis was used to ascertain　which clinical and radiographic signs may be of use in　predicting the outcome of endodontic treatment (Tables 5　and 6). The analysis revealed that the presence of canal　obliteration, root resorption, bridge abutment, or root perforation　was of importance to the prediction of the treatment　failure in cases with pulpal necrosis. In retreated cases, the　size of the periapical lesion and the extent of the root filling　to the root apex were found to be important. However, the　prediction of the frequency of failure in these two groups was　poor (3% predicted failure in cases with pulp necrosis versus　14% in the data; 18% predicted failure in retreated cases　versus 38% in the data). The predicted success or failure of　individual cases was also poor with both models. Only 3 of　28 (11%) failures in cases with pulp necrosis and 10 of 36　(28 %) of retreated cases were correctly classified as failures by　the models.

つまり

歯髄壊死歯や根尖病巣がある歯にクラウン修復やブリッジの支台歯とすることで

予後はあまり変わらなかった。

再根管治療歯では同じ様にした時

治療結果に対する影響に有意差は無かった。

患者の年齢・性別、深いポケットの有無、ポストが植立されるか否か

鈎歯となるか否か、根充前にサンプルされた細菌数の各要因は

治療結果に全く影響を与えなかった。

治療中の急性転化、初期の根尖膿瘍の存在どちらも治療結果に影響を与えなかった。

ファイルの破折やパーフォレションの頻度は少なかった。

前者は全体の1.3%、後者は1.5%だった。

根尖病巣は後々2本のファイル破折根管、3本のパーフォレーション根管で生じた。

段階的重回帰分析を行った所、閉鎖根管や根吸収やブリッジの支台になることやパーフォレーションは

歯髄壊死歯において治療が失敗する重要な要因になっていた。

再根管治療歯における根尖病巣の大きさと根充材の根尖への到達度は

治療の失敗頻度を予測する上で取るに足りないものだった

ということです。