抄 録 : 抜髄根管の成功率は85%, 未治療の感染根管は80%, 再治療の感染根管は56%と報告されている. 厚生労働省から発表される ｢社会医療診療行為別統計｣ (2019年6月審査分) から感染根管処置/抜髄の比率を求めた. 単根管で1.44倍, 2根管で1.16倍, 3根管以上で1.25倍, 合計で1.31倍であった. これは再感染根管治療の多さを示唆している. 次に根管治療の回数と時間から根管治療に必要な総時間を検討した. その結果, 抜髄から根管充塡までの総時間は単根管で228分, 2根管で250分, 3根管で274分, 4根管で288分および樋状根管で289分であった. 感染根管治療では同様に根管充塡までに単根管で224分, 2根管で250分, 3根管で269分, 4根管で285分および樋状根管で289分であった. 技術的に困難である感染根管治療のほうが抜髄より少なくなっている. 感染根管治療に対する意識の低さも感じるところである. 根管貼薬の回数が少なく1回の時間が長いほうが根管治療の効率は良くなるが, 1回の時間にかかわらず治療費は同評価になる矛盾を感じるところである.

 そこで, 急性期医療で用いられているDiagnosis Procedure Combination/Per-Diem Payment System (DPC/PDP : 診断群分類別包括支払い) 制度を応用できると考えた. すなわち, 術前のCBCTや非歯原生歯痛の検査を含めた詳細な手順を定めた検査を行い, 難治性根尖性歯周炎の原因を明確にする. その結果から, ICD10のK04.9歯髄及び根尖周囲組織のその他及び詳細不明の疾患として挙げられている傷病名を用い, 感染根管治療の困難さを示す. 新たな制度の評価については歯保連試案に準じてコスト調査, 治療時間による人件費を明確にし, 治療回数に依らない包括的な評価と経過観察を引き続いて行い治療の成否を判断する制度の導入によって質の高い治療が担保できることが望ましいと考える.

Abstract : Dental education has changed in the past decade with the introduction of CBT, OSCE and others, and the model core curriculum for dental education has been updated. We conducted a questionnaire survey to compare the endodontic instruments, materials and medicines currently used with the results of a previous study.

 The subjects were 29 departments and divisions in charge of education on endodontics across Japan. The collection rate was 100%.

 The results showed there is a difference in instruments used for coronal flaring among dental schools. Instruments for coronal flaring, root canal instrumentation, root canal medicaments, temporary filling, and root canal filling materials showed some difference between clinical training and clinical practice. Compared with the previous study, a major difference was found in instruments for coronal flaring. On the other hand, the use of hydrogen peroxide significantly decreased ; the main irrigants are now sodium hypochlorite and ethylenediaminetetraacetic acid. Also, the use of NiTi rotary files, resin sealers, and bioceramic sealers has increased.

 This study showed there are some differences between clinical training, clinical practice, and dental schools in comparison with the previous study performed ten years ago. These results can be used for making dental education more substantial and improving teaching effectiveness in the future.

Abstract : Purpose : The purpose of this study was to evaluate the detection rate and quantification of the new anaerobic culture single-file method, which can simply quantify the amount of anaerobic bacteria in a root canal at a clinic, in comparison with the pumping maximal removal (PMR) method.

 Materials and Methods : The anaerobic culture single-file method was used to survey a total of 200 root canal treatments performed on patients who gave informed consent at a clinic from September 2017 to February 2020. A sample was collected with one K file, and inoculation culture of an anaerobic culture plate was completed within a few minutes in the clinic using a microchip and micropipettor.

 Results : The correlation rate of positive and negative from the same root canal by the PMR method and the anaerobic culture single-file method was 95.0%, the detection rate was almost the same, and the number of detected bacteria had a strong positive correlation (the correlation coefficient＋0.9885).

 Conclusion : The detection rate and quantification by the anaerobic culture single-file method were similar to those of the PMR method, and were highly reliable.