A radiographic method for distinguishing noncavitated from cavitated proximal carious lesions: A proof of concept clinical trial

Abstract

Objectives: We propose a new topical radiographic contrast method for distinguishing noncavitated from cavitated radiolucencies. Laboratory tests and a pilot clinical trial were designed to test the feasibility and efficacy of the method.

Study design: Twenty-two adults with 27 proximal radiolucencies had conventional bitewing (BW) examinations. After exclusion, 21 surfaces were evaluated. A concentrated solution of sodium iodide was placed in the interdental spaces via a microsyringe and BWs were again exposed. A class II cavity preparation was made in the adjacent tooth and polysiloxane impressions were made of the study surfaces. The impressions were scanned by visible light, creating a high resolution 3D replica. Cavitations, if present, were measured.

Results: Nine surfaces were noncavitated and 12 surfaces were cavitated. The microsyringe dispensed a variable volume of liquid, which affected the accuracy of the test. The sensitivity for cavitation was 50%, specificity was 88.9%, and accuracy was 66.7%. This compares to a reported 60% sensitivity, 62% specificity, and 62% accuracy for BW examinations. Intraexaminer reliability for classifying noncavitated or cavitated lesions using the kappa test was 0.649.

Conclusions: This method needs improvement but was an advance over conventional BWs and could result in reduction of restorations in low- and high-risk patients.

Trial registration: ClinicalTrials.gov NCT01523509 NCT02359279.

Conflict of interest statement

Disclosures: Dr Benn was the Chief Science Officer, Firefly Health Innovations Inc. and shareholder in the company, which is now dissolved. Dr Benn was the Principal Investigator. Creighton University, Office of Research Integrity, provided a waiver of Conflict of Interest.

Copyright © 2021 Elsevier Inc. All rights reserved.

Figures

Figure 1.

Extracted permanent molar. A) Photograph of the proximal region with a shallow cavity (arrow) 0.18 mm deep with an adjacent non-cavitated lesion. B) Photograph of the impression of the tooth surface with an ovoid raised region of cavity (arrow). C) Direct 3D laser scan of the tooth surface with reconstruction of the cavity and surrounding proximal surface, orientated as occlusal on top, gingival on the bottom, and buccal and lingual surfaces on the left and right, respectively. Line 1 is a linear surface profile in the occlusal-gingival direction and line 2 is the profile in the buccal-lingual direction. (White bar =0.40 mm). C’) Photomicrograph of an undecalcified section of a mesiodistal slice through a cavity 0.29 mm deep into the enamel. (White bar = 1.00 mm). D) 3D laser scan reconstruction of the impression. (White bar = 0.40 mm). E) Surface profile line 2 in the buccal-lingual direction. E’) Profile line 1 in the occlusal-gingival direction. Note the similarity of the cavity profile in C’ to line 1 in E’. F) Profile line 2 and F’) profile 1 from the scan of the impression in D.

Figure 2.

Microsyringe containing 6 molar solution of sodium iodide (NaI). A) Hollow triangular wedge that fills the interdental space, with two side holes for solution to exit. B) Flexible hollow connector. C) Barrel-shaped reservoir for NaI. D) Thumb press button to eject 1.0 μL of solution.

Figure 3.

Microsyringe construction errors. Four mm long wedge tip, liquid side exit hole regions (black circles). A) Side hole nearest the viewer and far side hole are patent. B) Hole is almost blocked. C) Hole is blocked.

Figure 4.

Clinical study tooth #12 with a non-cavitated lesion on the distal surface. A) Photograph of the distal surface viewed through the adjacent box preparation of the mesial surface of tooth #13. The enamel is stained and roughened but has no cavitation. B) Scanned replica of the distal surface with the vertical white bar (2 mm) and horizontal white bar (3 mm), which corresponds to the white dotted box in image A. The intact surface shows small elevations that are probably small deposits of calculus over the lesion. C) Control bitewing with white arrow at limit of outer third dentin radiolucency on the distal portion of tooth #12. D) Sodium iodide solution appears as a radiopacity in the interdental space and on the contact region surface but with no penetration into radiolucency.

Figure 5.

Clinical study tooth #21 with shallow enamel erosion on the distal surface. A) The interdental papilla is blunted with an open interdental col. B) The distal surface of the tooth (#21D) viewed through the box preparation in tooth #20 with the arrow showing surface staining. C) Impression material of the distal surface is slightly roughened, indicating possible surface erosion (black arrow). D) Control bitewing showing a D1 radiolucency on #21D. E) Sodium iodide opacity filling the open interdental col space and lying on the interdental enamel surfaces above. There is a faint broad opaque band of NaI covering the gingival groove but it is below the distal radiolucency of #21. F) Scanned reconstruction showing shallow, moderately well-defined regions of erosion but no frank cavitation.

Figure 6.

Clinical study tooth #13 with a mesial cavitated lesion. A) The white cavitation (arrow) on the mesial surface has measurements of 1.75 mm × 1.40 mm × 0.56 mm deep. B) The scanned image covers a region of tooth surface 2.75 mm × 3.0 mm showing in the lower area a well-defined cavitation. However, the top left region of the cavity has a shallow lingual extension indicated by the arrow in Figure 6A and is not easily visualized in Figure 6B. C) Control bitewing with a black arrow indicating a D1 radiolucency on the mesial surface of tooth #13 (#13M) and the adjacent distal surface of tooth #12 (#12D), which has a D2 radiolucency. D) Sodium iodide opacity outlining the floors of the cavities in #13M and #12D. The interdental papilla is covered by NaI and the non-cavitated contact regions have a thin coating of NaI.