非う蝕性歯頸部病変（NCCL）を有する上顎小臼歯の修復前後におけるマイクロストレイン：ランダム化臨床試験

Loss of cervical tooth structure due to noncarious cervical lesions (NCCLs) can weaken teeth and increase tooth strain. Therefore, the aim of this study was to evaluate the in vivo microstrain variations in human maxillary premolars with NCCLs before and after restoration with resin composite (RC) and resin-modified glass ionomer cement (RMGIC).

This study was a split-mouth, randomized controlled clinical trial. Twenty patients aged 40-60 years with NCCLs in maxillary premolars were selected. Bite force was measured bilaterally. In Stage I, 10 patients with unilateral NCCLs were randomized and restored with RC and RMGIC. In Stage II, 10 patients with bilateral NCCLs received RC and RMGIC restorations after maxillary quadrant randomization. Bonded strain gauges recorded the coronal buccal microstrain after maximum intercuspation before and after restoration and at the six-month recall visit. Data were analyzed with the Wilcoxon signed-rank test, Mann-Whitney test, Fisher exact test, and Friedman test.

In Stage I, there was a significant reduction in mean coronal buccal microstrain immediately after restoration with RMGIC and RC (both p = 0.048) to values similar to that of intact control teeth (p = 0.486, p = 0.686); this reduction remained evident at the six-month recall (RMGIC: p = 0.014, RC: p = 0.040). In Stage II, there was a bilateral, significant reduction in mean coronal buccal microstrain immediately after restoration with RMGIC (p = 0.022) and RC (p = 0.011), which remained evident at the six-month recall visit (both p < 0.001).

Coronal buccal microstrain in teeth with NCCLs was significantly reduced after restoration with RMGIC and RC.