AIM To assess and correlate three distinct states of severely painful endodontically derived inflammation with their depiction on periapical radiographs using periapical index (PAI) scores. METHODOLOGY During a period of 15 months, 368 consecutively enrolled patients with suspected endodontic emergency conditions were examined at the University of Zurich, Center of Dental Medicine. Cases with a severely painful (Numeric Rating Scale, NRS-11 > 6) endodontically involved tooth and a clear pulpal and apical diagnosis (n = 162) were selected (one tooth per patient). Teeth were divided into three groups according to the clinically diagnosed main location of the inflammatory process: level 1: pulp (positive response to cold test), level 2: periodontium (no response to cold without swelling), level 3: periapical tissues (no response to cold with swelling). Periapical radiographs were obtained using a digital unit and analyzed by two calibrated observers. For level 2, which had the highest PAI variance (n = 76), the PAI scores were further scrutinized regarding their dependence on tooth location and the duration of pain. Data was analyzed using chi-squared and non-parametric tests, alpha = 0.05. RESULTS Overall, the PAI scores correlated well with the clinically diagnosed main location of periapical inflammation (Spearman's rho = 0.5131, P < 0.001), with level 1 having the lowest scores by far (P < 0.001) and level 2 having significantly lower scores compared to level 3 (P < 0.05). However, a PAI score of 5 was found in merely 3 teeth within the whole cohort, and 49% of the teeth in the level 2 group had no radiolucency (PAI < 3). Within level 2, the PAI scores were not dependent on tooth location but were substantially (P < 0.001) higher for teeth which had hurt for more than one week, and for root-filled teeth. CONCLUSIONS For the analyzed, severely painful endodontically involved teeth, the clinically diagnosed main location of inflammation was reflected by the periapical index. PAI scores were not significantly influenced by anatomical noise, yet in some cases under-estimated the clinical situation.

中文翻译：

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在严重疼痛的牙髓受累牙齿中，临床诊断的炎症过程与根尖指数得分之间的相关性。

目的使用根尖周指数（PAI）评分评估根尖周牙根管炎的三种不同状态，并将其与根尖周射线照片上的描述进行关联。方法在15个月的时间内，对苏黎世大学牙科医学中心的368名连续入组的疑似牙髓紧急情况的患者进行了检查。选择严重牙痛（数值评定量表，NRS-11> 6）且牙髓受累且牙髓和根尖明确的诊断（n = 162）的病例（每位患者一颗牙齿）。根据临床上诊断出的炎症过程的主要部位将牙齿分为三组：第1级：牙髓（对感冒测试呈阳性反应），第2级：牙周膜（对感冒无肿胀无反应），第3级：根尖周围组织（对冷与肿胀无反应）。使用数字单元获得根尖射线照相，并由两名校准的观察者进行分析。对于具有最高PAI方差（n = 76）的第2级，将进一步检查PAI分数是否取决于牙齿位置和疼痛持续时间。使用卡方检验和非参数检验分析数据，α= 0.05。结果总体而言，PAI评分与临床诊断的根尖周炎的主要部位相关性很好（Spearman的rho = 0.5131，P <0.001），与之相比，第1级的得分最低（P <0.001），而第2级的得分则明显更低达到3级（P <0.05）。但是，整个队列中只有3颗牙齿的PAI评分为5，而2级组中49％的牙齿没有射线透亮性（PAI < 3）。在2级以内，PAI分数与牙齿位置无关，但对于受伤超过一周的牙齿以及根部充填的牙齿，PAI分数明显较高（P <0.001）。结论对于经分析的，严重疼痛的牙髓受累牙齿，其临床诊断的主要炎症部位是通过根尖周指数来反映的。PAI分数不受解剖噪声的显着影响，但在某些情况下低估了临床情况。