インプラント埋入手術の新たな難易度分類についての予備的検討

抄録

In training institutions for dental implants, operative cases should be allocated on the basis of the surgeon's experience and skill set ; appropriate case selection both safeguards patients and allows the trainee to amass experience and skills to be an accredited implant specialist. Currently, case selection relies on the subjective judgment of the senior surgeon and objective measures are not usually employed. The aim of this study was to introduce a new system which we developed from objective criteria to measure the surgical complexity of operative cases, and to classify the clinical cases in comparison with the SAC classification (Classification of the Swiss Society of Oral Implantology (1999) ; “SAC”) and subjective classification by experts.
Three tiers of operative difficulty (Beginner, Middle, Senior Classification ; BMS Classification) were established using five levels of five elements to give a total BMS score of 5-25 points. The five elements were Function, Aesthetics, Number of implants, Strength and Duration, which were given a score of 1 to 5 points each. Cases with a total score of 5-7 were classified into Beginner (B), those with a score of 8-13 were classified into Middle (M), and those with a score of 14-25 were classified into Senior (S), and the condition to be an operator for cases of each stage is determined by the number of surgeries assisted or performed.
Preoperative clinical records of 80 implant surgery cases performed at Showa University Dental Hospital from November 2012 to December 2013 were extracted and analyzed retrospectively. These cases were classified by both the BMS and SAC Classification and in addition, the BMS scores of the cases that were assigned to two beginner dentists in their first year and two senior dentists were evaluated. The 80 cases were classified into S : 65%, A : 17.5%, and C : 17.5% by SAC, and B : 26%, M : 49%, and S : 25% by BMS. Approximately 50% of S stage cases by SAC were classified into M stage by BMS. The majority of the cases assigned to the beginner dentists were classified into B stage, and those of senior dentists were classified into M or S stage.
The results of this preliminary study suggest that the new classification system has excellent ability to identify cases suitable for beginner surgeons, which might be of particular benefit to educational institutions that can use the same system to allow step-wise progression to more advanced cases in an objective and logical manner.