This study investigated the progression of incisal tooth wear clinically for 4-years, using various diagnostic methods. Effectiveness of occlusal splints (night guards) for patients with nocturnal bruxism was also evaluated. Materials and Fourty maxillary incisors from 10 patients with nocturnal bruxism were selected. Group 1 (n=5) wore occlusal splints for 6 months, whereas group 2 (n=5) didn’t. Ultrasound, cast-model analysis (control), digital radiography, Fluorecam and colorimeter were used for measurements. Clinical progression of incisal wear monitored at baseline, 3, 6, 12, 24 and 48 months, respectively. Ultrasound, cast-model analysis and Fluorecam readings gradually and significantly decreased during the overall evaluation period for both groups (p<0.001). Regarding colorimeter, significant differences in periodical measurements were observed from 24 months and 12 months, for group 1 and group 2, respectively (p<0.001). There were no significant differences in readings at evaluation periods, between the groups, for ultrasound, digital radiography and cast-model analysis (p≥0.05), however significant differences were observed for colorimeter at 24 months (p=0.010) and 48 months (p<0.001), and for Fluorecam at 12, 24, 48 months (p<0.001). Annual decrease in mean crown length was determined as 20-30 µm for group 1 and 40-50 µm for group 2. The decreases in mean crown length were significantly lower for group 1 compared to group 2, regarding the assessments for 1 year, 2 years and 4 years (p<0.001). Positive and good correlations were observed between ultrasound, cast-model analysis and Fluorecam measurements (p<0.001). Ultrasound, Fluorecam and colorimeter showed promising results for monitoring any change and progression of incisal tooth wear clinically. Ultrasound might be considered as a quantitative, reliable and repeatable method. Precision of the measurements varied among the diagnostic methods used. Occlusal splints may have a potential preventive effect for progressive tooth wear.