Objective assessment of simulated non-carious cervical lesion by tridimensional digital scanning

Intraoral scanners as tracking devices: A dental protocol for assessing volumetric changes between intraoral scans

Intraoral scanners (IOSs) are digital data acquisition technologies that ease the recording of virtual diagnostic casts. Some IOSs have a specific software tool to assess volumetric changes between 2 scans acquired on the patient at different times. The scans are superimposed and volumetric differences between both meshes are reported. However, these software tools may be limited to scans captured only by the IOS of the same manufacturer. The present manuscript describes a protocol for comparing volumetric changes between 2 scans recorded using any IOS. Additionally, 1 of the scans is divided into 3 sections to minimize the alignment distortion and maximize the evaluation of the volumetric changes.

A depth-resolved quantitative evaluation method for non-carious cervical lesions treatment with optical coherence tomography

OBJECTIVES

The aim of this study is prognostic assessment of surface smoothness and the presence of internal bubbles after treatment of non-cancerous cervical lesions (NCCLs) using optical coherence tomography (OCT).

METHODS

After treatment with NCCLs, cross-sectional images of the lesion parts of the sample were non-invasively acquired and analyzed. The surface smoothness between tooth and resin, resin and cemento-enamel junction, and the presence bubble inside resin was confirmed. In addition, using an algorithm that distinguishes between resin and dental structure based on OCT cross-sectional images, we quantitatively analyzed the amount of resin used in treating NCCLs and acquired 3D images.

RESULTS

The inner structure of the resin in each sample was checked, and the presence of bubbles was confirmed. In addition, the resin sections were separated from the tomographic images acquired by OCT to visualize 3D images. The volume of resin used in the treatment part of each NCCLs samples was quantitatively analyzed as 3.7216 ∼ 14.889 mm3.

CONCLUSIONS

OCT is able to measure not only the surface abrasion provided by existing intraoral scanner, but also the size and depth location of interal bubbles, which is distinctive advantage of our method. Based on our results, OCT is a significant tool for qualitative and quantitative analysis of dental NCCLs treatment before and after treatment.

CLINICAL SIGNIFICANCE

The study used OCT, a non-destructive diagnostic, to reveal the structure of the resin and the location and size of bubbles after NCCLs treatment. These findings could be golden standard in determining the prognosis of NCCLs treatment.

Objective assessment of simulated non-carious cervical lesion by tridimensional digital scanning - An in vitro study

OBJECTIVE

Clinical assessment of progression of non-carious cervical lesions (NCCLs) is currently based on subjective methods. We hypothesize that 3D digital intraoral scanners (IOS) can provide quantitative outcomes for objective measuring and monitoring of NCCLs. This in vitro study verified the reliability of IOS to monitor dental structure loss of simulated NCCLs, in comparison to a reference bench-top 3D optical profilometer (BTS).

METHODS

NCCLs of different severity levels (early, moderate, or severe, n = 150) were simulated in a preceding study. Impressions of the lesions were taken and scanned with both BTS (ProScan; Scantron) and IOS (TRIOS4; 3Shape). Generated 3D images were analyzed for volumetric tooth loss (mm3) by superimposition followed by subtraction analysis. ProForm (Scantron) and WearCompare (Leeds Digital Dentistry) software were used in association to BTS and IOS, respectively. Agreement was assessed using intraclass correlation coefficient (ICC, alpha=0.05) and Bland-Altman plots.

RESULTS

ICC (confidence interval at 95 %) between IOS and BTS for all data combined was 0.962 (0.942-0.973), showing excellent reliability. Subset analyses showed that NCCLs with lower volume loss (early- and moderate-stage lesions) resulted in moderate ICCs, whereas severe lesions showed excellent ICC. Bland-Altman plots demonstrated general good agreement, with narrower limits for early stage-lesions.

CONCLUSION

IOS data demonstrated good agreement to BTS, when measuring tooth structure loss in simulated NCCLs, with particularly higher ICC in more severe lesions. Considering the accessibility and ease-of-use, IOS showed to be a good alternative for the objective assessment of NCCLs in vitro.

CLINICAL SIGNIFICANCE

3D intraoral scanners' accessibility and objectivity make them potentially valuable tools for assessing and monitoring NCCLs.

Accuracy and precision of intraoral scanners for shade matching: A systematic review

STATEMENT OF PROBLEM

The use of intraoral scanners is rising in prosthetic dentistry; however, systematic analysis of their accuracy and precision for shade matching is scarce.

PURPOSE

The purpose of this systematic review was to evaluate the accuracy and precision of intraoral scanners for shade matching.

MATERIAL AND METHODS

In addition to a manual search, an electronic systematic search was conducted on MEDLINE/PubMed, EMBASE, Web of Science, Cochrane, and Scopus databases. English-language original studies published between January 1, 2010 and March 1, 2022 with intraoral or digital scanners were chosen based on the keywords of tooth color or shade selection or determination, color or shade matching, accuracy, validity, or trueness, and precision, repeatability, or reproducibility as inclusive criteria. Two reviewers independently performed the literature search, selected the studies, collected the data from the studies included, and evaluated the quality of the studies included using a quality assessment method and the Joanna Briggs Institute Critical Appraisal Checklist for Quasi-Experimental Studies. A third reviewer resolved disagreements.

RESULTS

A total of 17 articles concerning the shade matching accuracy and precision of intraoral scanners were selected and reviewed. Among them, 4 articles evaluated only accuracy, 4 articles assessed only precision, and 9 articles investigated both accuracy and precision. Ten articles reported low levels of shade matching accuracy for intraoral scanners, while 11 articles reported high levels of shade matching precision for intraoral scanners.

CONCLUSIONS

Based on the current literature, intraoral scanners show acceptable precision but unacceptable accuracy for shade matching.

[Efficacy of tunnel technique for treatment of gingival recession of upper adjacent teeth with noncarious cervical defect]

OBJECTIVE

To evaluate the efficacy of tunnel technique (TUN) in treatment of teeth with adjacent gingival regression (GR) combined with noncarious cervical lesions (NCCL).

METHODS

We collected data from 21 patients (79 teeth) undergoing TUN surgery for GR combined with NCCL. According to GR depth (GRD) and lesion depth (LD) of NCCL, the teeth were divided into group 1 with GRD≤3 mm and LD≤1 mm; group 2 with GRD≤3 mm and LD>1mm; group 3 with GRD>3 mm and LD≤1 mm; and group 4 with GRD>3 mm and LD>1 mm. The mean root coverage (MRC) rate, complete root coverage (CRC) rate, keratinized gingival width, and keratinized gingival thickness were compared among the 4 groups after TUN surgery.

RESULTS

The keratinized gingival width and thickness were significantly improved after the surgery in the 4 groups. When the GRD was below 3 mm, the MRC was not significantly different between group 1 and group 2 (8.55% vs 95.45%, P>0.05); When the GRD was beyond 3 mm, the MRC and CRC rates were both decreased in group 3 and group 4, especially in group 4, where the CRC rate (25%) was significantly lower than those in the other 3 groups (P < 0.01).

CONCLUSION

In patients with GR combined with NCCL, TUN surgery can obviously improve keratinized gingival width and thickness. GRD has a greater effect on the outcome of root coverage than LD, suggesting that NCCL restoration before TUN surgery may not be necessary. Both GRD and LD should be considered in the evaluation of the clinical efficacy of TUN surgery.