Impact of angle on photothermal radiometry and modulated luminescence (PTR/LUM) value

Haixia Xing; George J Eckert; Masatoshi Ando

doi:10.1016/j.jdent.2023.104500

Impact of angle on photothermal radiometry and modulated luminescence (PTR/LUM) value

J Dent. 2023 May:132:104500. doi: 10.1016/j.jdent.2023.104500. Epub 2023 Apr 2.

Authors

Haixia Xing¹, George J Eckert², Masatoshi Ando³

Affiliations

¹ Department of General Dentistry, Peking University School and Hospital of Stomatology, Beijing, China; Department of Cariology, Operative Dentistry and Dental Public Health, Indiana University School of Dentistry, 1121 W. Michigan Street, Indianapolis, IN 46202, USA.
² Department of Biostatistics and Health Data Science, Indiana University School of Medicine, Indianapolis, IN, USA.
³ Department of Cariology, Operative Dentistry and Dental Public Health, Indiana University School of Dentistry, 1121 W. Michigan Street, Indianapolis, IN 46202, USA. Electronic address: mando@iu.edu.

PMID: 37015184
DOI: 10.1016/j.jdent.2023.104500

Abstract

Objective: To evaluate the impact of scanning angles to detect/quantify non-cavitated caries by photothermal-radiometry and modulated-luminescence (PTR/LUM, Canary System) and to evaluate the association of PTR/LUM value with lesion depth (LD), including sound tissue thickness under the lesion (ST).

Methods: Thirty human extracted premolars were selected based on micro-computed tomography [μ-CT: sound (n=12), lesions into outer-half of enamel (n=6), lesions into inner-half of enamel (n=6), lesions into outer one-third of dentine (n=6)]. Each tooth sample was scanned 90° directly contacted to the center of non-cavitated lesion or sound smooth surface, and tilted 10° and 20° in four directions: buccal/lingual/occlusal/cervical. The procedure was repeated 48 h later. Lesion depth and ST [ST=5000 µm (maximum PTR/LUM scanning depth)-LD] were measured at the same scanning direction on μ-CT images. Sensitivity, specificity, area under the Receiver Operating Characteristic curve (AUC), and intraclass correlation coefficients (ICC) for different scanning angles were calculated. Sensitivity was further evaluated based on lesion extensions. Relationships between PTR/LUM value and lesion depth, and between PTR/LUM value and LD/ST-Ratio were evaluated.

Results: PTR/LUM value showed significant differences among scanning angles. Overall sensitivity (78%-89%), specificity (66%-87%), AUC (0.86-0.92) and ICC (0.89-0.99), sensitivity based on lesion extensions presented no significant differences among angles. PTR/LUM value showed moderate correlations (0.56-0.74) with deepest lesion depth and LD/ST-Ratios.

Conclusion: The scanning angle within 20° increments might impact PTR/LUM value statistically; however, it did not affect PTR/LUM detection performance. PTR/LUM values were positively correlated with non-cavitated lesion depth, and not affected by sound tissue thickness under the lesion.

Clinical significance: Clinically, it is challenging to measure/scan at the same location and same angle longitudinally, however, it is important to standardize these parameters. Scanning within 20° deviation from perpendicular did not affect detection performance of PTR/LUM, and PTR/LUM value showed positive moderate correlation with caries depth.

Keywords: Dental caries; Dental enamel; Early diagnosis; Optical device; Scanning angle; Tooth demineralization.

MeSH terms

Dental Caries* / diagnostic imaging
Humans
Luminescence*
Luminescent Measurements / methods
Radiometry / methods
Sensitivity and Specificity
X-Ray Microtomography