In vivostudy of pixel grey-measurement in digital subtraction radiography for monitoring caries remineralization

Enhanced effectiveness of silver diamine fluoride application with light curing on natural dentin carious lesions: an in vitro study

This study aimed to compare the mean mineral density difference (mMDD) and surface morphology of 10- and 60-s silver diamine fluoride (SDF)-applied dentin carious lesions and to study the effect of an additional 20-s light curing (LC) on SDF-treated teeth. Forty primary molar blocks with natural dentin carious lesions were measured for baseline lesion depth and mineral density using Image-Pro Plus software. The samples were randomly distributed into 4 groups; 38% SDF applied for 1) 10-s (10SDF), 2) 60-s (60SDF), 3) 10-s + LC (10SDF + LC), 4) 60-s + LC (60SDF + LC) and an additional control group to assess the outcome of pH-cycling only. Then all the groups underwent a 7-d bacterial pH-cycling. The dentin carious lesions' mMDD was determined by digital subtraction radiographic analysis. The surface morphology and elemental profile were assessed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The mMDD of the dentin lesions was analyzed using two-way ANOVA, generalized linear models analysis. Light curing was the only factor that affected the mMDD (p = 0.007). The mMDD in the 10SDF + LC and 60SDF + LC groups were significantly higher than those without light curing (p = 0.041 and 0.041, respectively). The 60SDF + LC group demonstrated a significantly higher mMDD than the 10SDF group (p = 0.010), while that in the 10SDF + LC group was similar to the 60SDF group (p = 1.00). Scanning electron microscopy revealed denser mineral content layers, which were likely silver and chloride, in the 10SDF + LC and 60SDF + LC groups than in the 10SDF and 60SDF groups, respectively. In conclusion, shortened application time with light curing enhanced SDF remineralization similarly to the conventional method.

Radiographic modalities for diagnosis of caries in a historical perspective: from film to machine-intelligence supported systems

Radiographic imaging for the diagnosis of caries lesions has been a supplement to clinical examination for approximately a century. Various methods, and particularly X-ray receptors, have been developed over the years, and computer systems have focused on aiding the dentist in the detection of lesions and in estimating lesion depth. The present historical review has sampled accuracy ex vivo studies and clinical studies on radiographic caries diagnosis that have compared two or more receptors for capturing the image. The epochs of film radiography, xeroradiography, digital intraoral radiography, panoramic radiography and other extraoral methods, TACT analysis, cone-beam CT and artificial intelligence systems aiding in decision-making are reviewed. The author of this review (43 years in academia) has been involved in caries research and contributed to the literature in all the mentioned epochs.

Detecting demineralization of enamel and cementum after gamma irradiation using radiographic densitometry

The purpose of this study was to evaluate the ability of radiographic densitometry in detecting the early demineralization of human enamel and cementum in irradiated and non-irradiated teeth. Sixty extracted teeth were divided into two groups: irradiated group and non-irradiated group. After irradiation, the groups were subjected to demineralization-remineralization (PH) cycling. Radiographic densitometric measurements (gray values) of a selected area of interest in the enamel and in the cementum of each tooth were performed at baseline and after PH cycling. After PH cycling, there was a significant reduction in gray values for both groups. The difference between "baseline" and "after PH cycling" values represents the reduction in the mineral content of the hard tissue, i.e., the demineralization. Results show that the demineralization of irradiated tooth enamel and cementum was significantly higher compared to that of non-irradiated tissues as determined by gray-level values. It is concluded that densitometric measurements by means of digital radiographs allow for the detection of demineralization of enamel and cementum, and can be used successfully for diagnosis of the early carious lesions in patients who received head and neck radiotherapy. This will allow implementation of remineralizing therapy and avoid the risk of progression of radiation caries. Furthermore, it is concluded that gamma irradiation with typical therapeutic doses for head and neck carcinoma is a direct cause of demineralization of tooth enamel and cementum.

Conventional and digital radiographic assessment of tooth enamel de-/remineralization processes: an experimental study

OBJECTIVE

This study aimed to compare digital techniques for evaluating dental enamel de-/remineralization.

MATERIALS AND METHODS

Sixty extracted molars were subjected to a process of de- and remineralization. Radiographs were taken before and after each stage. These radiographs were evaluated by the conventional method and were then scanned and analyzed either with or without the use of image enhancement. Moreover, the gray levels (GLs) of the affected areas were measured.

RESULTS

All methods exhibited low sensitivity and identical levels of specificity (99.4%). Analysis of the grayscale levels found statistically significant differences between the initial radiographs (P < 0.05). The mean GL of the carious group was significantly lower than that of the remineralized group. The GL did not differ significantly between the initial and final radiographs of the remineralized group, although the mean of the first group was lower than that of the second, which demonstrated that the remineralization process restored the normal density of the dental enamel.

CONCLUSION

Measurement of the mean GL was sufficiently sensitive to detect small alterations in the surface of the enamel.

Quantitative pixel grey measurement of the "high-risk" sign, darkening of third molar roots: a pilot study

OBJECTIVES

Our aim was to examine the panoramic darkening of the root, which is a "high-risk" sign, using quantitative measurements of pixel grey values to determine different aetiological backgrounds, namely inferior alveolar nerve (IAN) exposure with or without groove formation of the third molar roots or thinning/fenestration of the lingual cortex (LCTF).

METHODS

38 impacted third molars that had been surgically removed and had darkened roots on panoramic radiographs were included in this retrospective case-control study. 15 IAN exposure cases were selected for the case group, and 23 cases with proven lingual cortical thinning or fenestration were chosen for the control group. The mean pixel grey values of selected areas in the dark band (D) and control areas within the same roots (R) were determined with the ImageTool (University of Texas Health Science Center, San Antonio, TX) software. The differences in pixel values (R-D) of the IAN and LCTF groups were analysed using the Mann-Whitney U-test and Pearson's χ(2) test.

RESULTS

The medians of the R-D pixel values were 45.7 in the IAN group and 34.3 in the LCTF group, whereas the interquartile ranges were 12.0 (IAN) and 18.3 (LCTF) (p < 0.001). The R-D critical value at which the outcomes differed significantly was 38. If the differences in pixel grey values (R-D) were higher than 38, the chance of IAN exposure was approximately 32 times higher than the chance of LCTF (χ(2) test, p < 0.001; odds ratio, 32.0; 95% confidence interval, 3.5-293.1).

CONCLUSIONS

The pre-operative prediction of IAN exposure or lingual cortical thinning in cases with "darkening" is possible based on pixel grey measurements of digital panoramic radiographs.

Does the use of an intramedullary nail alter the duration of external fixation and rate of consolidation in tibial lengthening procedures? A systematic review

We performed this systematic review to evaluate tibial lengthening procedures with the use of an intramedullary nail. We investigated the hypothesis that lengthening over a nail can reduce the time spent in an external fixator and increase the rate of consolidation thereby reducing the risk of complications and improving patient satisfaction. We conducted a comprehensive literature search using the MEDLINE, EMBASE and PubMed databases using the key words 'tibia' or 'tibial lengthening' and 'nail'. This search was performed in December 2011 and repeated by both authors. Specific outcome measures were the duration of external fixation, rate of consolidation and complication rates. A total of 6 comparative studies published between 2005 and 2011 consisting of 494 procedures met our inclusion and exclusion criteria and were eligible for critical appraisal. The methodological quality of the studies was variable, and they were not homogenous enough for meta-analysis. Patients who have tibial lengthening over an intramedullary nail spend significantly less time in an external fixator. However, there is no reliable evidence to suggest that the rates of consolidation or complication are any different to those lengthened without an intramedullary nail.

A novel LED-based device for occlusal caries detection

The aim of this in-vitro study was to compare the performance of laser-based (DIAGNOdent, KaVo, Biberach, Germany) and LED-based (Midwest Caries I.D., DENTSPLY Professional, New York, USA) caries detectors in the detection of occlusal caries in permanent molars. The study consisted of 129 visually sound or non-cavitated pits or fissures in 82 extracted permanent human molar teeth. Two trained examiners used the laser-based and LED-based caries detectors to examine the fissures for caries. The teeth were then sectioned at the surfaces suspected of containing occlusal caries and histologically evaluated using stereomicroscopy as a gold standard. Inter-examiner reliability of the caries detector examination was assessed using Cohen's Kappa statistics. The sensitivity, specificity, and accuracy in diagnosing occlusal caries using the two devices were calculated according to appropriate cut-off scores. Receiver operating characteristic (ROC) curves were also determined to compare the diagnostic performance of the devices in occlusal caries diagnosis. The cut-off level of significance was taken as p = 0.005. Cohen's Kappa showed substantial agreement for the laser-based caries detector (0.74), and almost perfect agreement for the LED-based (0.89) caries detector. The specificity of the laser-based device varied from 0.49 to 0.97 at T1 and T2. Its sensitivity varied from 0.33 to 0.65 at T1 and T2. The specificity of the LED-based device varied from 0.48 to 0.56 at T1 and T2. Its sensitivity varied from 0.65 to 0.84 at T1 and from 0.80 to 0.84 at T2. Taking the limitations of the current study into consideration, the DIAGNOdent laser pen was more accurate in determining when teeth were free of occlusal caries than was the Midwest Caries I.D. LED-based device, although the Midwest Caries I.D. device more often revealed the presence of occlusal caries than did the DIAGNOdent pen.

Comparative study of callus progression in limb lengthening with or without intramedullary nail with reference to the pixel value ratio and the Ru Li's classification

INTRODUCTION

Callus progression is a great concern during limb lengthening. In this study, we investigated the difference in callus progression between tibial lengthenings with and without intramedullary nail.

METHOD

Seventy tibiae in 38 patients with an average age of 24 years were lengthened with Ilizarov external fixator and nail; 56 tibiae in 40 patients with an average age of 28.6 years were lengthened with the same Ilizarov external fixator but without nail. The callus progression was compared with reference to pixel value ratio (PVR) and Ru Li's classification. Statistical analysis was performed to compare the variation trend of PVR and incidence of various callus pathways (particular patterns of callus progression as outlined in Ru Li's classification) and shapes of each aspect of callus between the two groups.

RESULTS

The trend of PVR was not statistically different in posterior, lateral and medial aspects of the callus between the two groups, but averagely lower in the anterior aspect in the group without nail than that with nail. The group without nail presented less incidence of homogeneous pathway, greater incidence of heterogeneous pathway; also greater incidence of fusiform callus, less incidence of cylindrical callus.

CONCLUSION

It was concluded that with nail, the callus underwent a more favorable progression and even longer lengthening could be allowed.

Qualitative and quantitative radiographic assessment of sealed carious dentin: a 10-year prospective study

OBJECTIVE

The objective of this study was to assess radiographic outcomes after partial carious dentin removal performed in deep caries lesions over a 10-year period.

STUDY DESIGN

Baseline image was compared to 3 follow-up radiographs (at 6-7 months, 3 years, and 10 years). Tertiary dentin deposition and lesion depth were qualitatively assessed. Radiographic density changes in the radiolucent zone (RZ) beneath the restoration were quantitatively compared to the control areas (CA) using digital subtraction radiography (Friedman repeated-measures analysis of variance).

RESULTS

A total of 13 teeth were evaluated. In most cases, lesion depth remained unchanged or decreased (12/13) and tertiary dentin formation was observed (10/13) after the 10-year follow-up. Differences between RZ and CA at the 6- to 7-month and 3-year follow-up periods were similar but significantly lower than those at the 10-year assessment.

CONCLUSIONS

Sealing of carious dentin arrested the caries process, promoted deposition of tertiary dentin, and induced mineral gain in the radiolucent zone.