A digital subtraction radiography investigation of upper first molar proximal bone density changes in adolescents

Reproducibility of subtraction radiography in monitoring changes in approximal carious lesions in children: An in vivo study

BACKGROUND

Laboratory studies have shown that digital subtraction radiography (DSR) can be a more effective tool, than conventional radiography, in monitoring changes in carious lesions. The clinical performance of the technique, however, has not been sufficiently researched.

AIM

To compare the reproducibility of DSR to that of bitewing radiographs, in monitoring changes in approximal caries in the mixed dentition. A secondary aim was to determine whether assessment outcomes differed as a function of the method used.

DESIGN

Six assessors evaluated 310 lesions first on bitewings, then with DSR. The overall reproducibility was evaluated via intra-class correlation coefficient (ICC). Intra- and inter-rater reproducibility were assessed using weighted Kappa. Paired t test was used to assess differences in the reproducibility across methods.

RESULTS

The overall reproducibility for DSR was (ICC = 0.47, 95% CI = 0.31-0.56). Intra- and inter-rater reproducibility were 0.65 and 0.44, respectively. The overall reproducibility for bitewings was ICC = 0.45, 95% CI = 0.42-0.57. Intra- and Inter-rater reproducibility were 0.71 and 0.46, respectively. Differences in the reproducibility across methods were not statistically significant. Significantly more lesions were scored as progressed using DSR.

CONCLUSIONS

The reproducibility of DSR in monitoring changes in approximal caries is comparable to that of bitewings. Additionally, DSR detected higher proportion of progression than bitewing assessments.

Accuracy and reproducibility of conventional radiographic assessment and subtraction radiography in detecting demineralization in occlusal surfaces

Subjective interpretation of paired digital radiographic images viewed side by side to assess occlusal lesion progression, arrest or remineralization is difficult. The aim of this study was to compare the accuracy and reproducibility of a digital subtraction radiography technique and visual assessment of paired digital images in detecting changes in mineral content within occlusal cavities. Forty molar teeth with occlusal cavities were placed in arches and baseline digital radiographs taken. Nineteen teeth were randomly selected and had acid placed in the cavities and digital images taken after 3, 6, 12, 18 and 24 h of acid exposure. Paired baseline images and those taken at the various time intervals were examined side by side and assessed for demineralization by five examiners. Subtraction images prepared from the paired images were assessed in the same way. One fifth of the images were re-examined to determine intra-examiner reproducibility. After 12 h or longer the diagnostic accuracy (mean area under the ROC curve = 0.92-0.98 for subtraction radiography), intra-examiner and inter-examiner reproducibility for detection of demineralization from the subtraction images was significantly better than viewing the paired images side by side (p < 0.01). The subtraction radiography system used was found to be more accurate and reproducible than visual assessment of paired digital images. As such the technique shows promise for monitoring occlusal lesion progression in clinical studies.

A pilot study of treatment of periodontal-endodontic lesions

OBJECTIVE

A pilot study to evaluate a standardised treatment protocol for combined periodontal-endodontic lesions (involving staged endodontic and periodontal treatment).

PARTICIPANTS

Nine patients with a diagnosis of a combined periodontal-endodontic lesion.

METHODS

At baseline, root canal treatment (RCT) was performed by a standard protocol, and simple scaling/oral hygiene instruction provided. After one month, a standardised episode of non-surgical periodontal treatment was undertaken to address residual pocketing. Clinical measurements, including probing depths, attachment levels and bleeding on probing were recorded at baseline, month one and month three. Long-cone periapical radiographs taken using standardised projection geometry at baseline and month three were analysed for bone changes using digital subtraction radiography (DSR).

RESULTS

During the study, one patient's affected tooth was extracted. From baseline to month three, there were statistically significant mean probing depth reductions (delta= 0.95mm, 95% CI= 0.20mm, 1.70mm; p= 0.02), mean attachment gains (delta= 1.13mm, 95% CI= 0.29mm, 1.96mm; p= 0.02) and reduction in mean bleeding on probing (delta= 29%, 95% CI= 10%, 49%; p= 0.01). DSR analysis revealed that between month 0 and month three, four teeth demonstrated bone gain, two teeth exhibited bone loss and two teeth showed no change. The mean bone change was in favour of bone gain but failed to achieve statistical significance (p>0.05).

CONCLUSIONS

Within the limitations of this pilot study, treatment of periodontal-endodontic lesions by performing RCT prior to periodontal treatment was effective, resulting in improvements in clinical parameters together with alveolar bone gains in a majority of teeth.

An in-vitro and in-vivo methodology study of alveolar bone measurement using extra-oral radiographic alignment apparatus, Image Pro-Plus® software and a subtraction programme

OBJECTIVES

(a) To validate a method for acquiring reproducible radiographic images and repeatable measurements of digital images. (b) To investigate the clinical and radiographic changes following periodontal surgery and in a periodontally healthy control group.

METHODS

In-vitro study. Sixteen dried human skulls had replicate intra-oral radiographs taken using an extra-oral alignment apparatus under simulated clinical conditions, and measurements were made on the images using Image Pro-Plus analysis software. In-vivo study. Seven subjects, aged 38-63 years with chronic periodontitis, were treated using replaced flap surgery. Nine patients with healthy periodontal tissues were recruited as a control group. Clinical measurements and radiographs were taken pre-surgery and 6 months afterwards, and at the same interval for untreated healthy controls using the alignment apparatus. Radiographs were analysed using Image Pro-Plus and subtraction radiography.

RESULTS

Radiographs had a high degree of reliability (ICC 0.98-0.99) for the in-vitro study and intra-operator repeatability of measurements was high (ICC 0.65-0.99) for the in-vivo study. Over this interval there were both significant clinical improvements and in bone gain within infra-bony defects on radiographs. Subtracted images showed that out of 17 surgically treated sites, 13 showed evidence of bone gain, one showed no change, two showed bone loss and one could not be interpreted due to poor alignment. Overall there were no significant clinical or radiographic changes in the control group.

CONCLUSIONS

Radiographic images were highly reproducible. Measurements had a high degree of repeatability. The methods used allowed accurate quantitative and qualitative measurement of change in alveolar bone. This technique would allow accurate measurement of any changes in alveolar bone levels in patients with periodontal disease.

Periodontal maintenance in a specialist periodontal clinic and in general dental practice

OBJECTIVES

To monitor the efficacy of periodontal maintenance whether conducted in a specialist periodontology clinic or in the practice of the referring general dentist.

MATERIALS AND METHODS

Thirty-five subjects with a diagnosis of moderate-severe chronic periodontitis who were referred to the specialist clinic received periodontal non-surgical therapy. Following a 6-month healing phase, subjects were randomly allocated to one of two groups: A (n=18, periodontal maintenance provided within the specialist clinic) or B (n=17, periodontal maintenance provided by the referring general dentist in accordance with written instructions provided by the specialist). All subjects were examined at months 0 (corresponding to 6 months post-completion of non-surgical therapy), 6 and 12. Full-mouth plaque index (PI), % bleeding on probing (%BOP) and probing depth (PD) measurements were recorded. PDs were also recorded at eight test sites which, prior to non-surgical therapy, exhibited PD 5-8 mm, BOP and radiographic alveolar bone loss. Standardized radiographs were exposed at test sites at months 0 and 12, and bone changes assessed using digital subtraction radiography (DSR).

RESULTS

As a result of the non-surgical therapy, statistically significant improvements in all clinical parameters were recorded. In the maintenance period, mean PI increased significantly from months 0 to 12 (p<0.05), but this increase did not differ significantly between groups A and B (p>0.05). No other clinical parameters changed significantly in the maintenance phase of the study. Reductions in %BOP, mouth mean PD and mean test sites PD achieved by the non-surgical therapy were maintained and did not differ significantly whether subjects were allocated to group A or group B (p>0.05). Current smokers had significantly deeper PD than non-smokers and former smokers at all time points (p<0.05), although otherwise, smoking status did not affect the outcomes of the study. DSR analysis identified statistically non-significant, slight, alveolar bone loss in both groups between months 0 and 12.

CONCLUSION

In the short term, periodontal maintenance can be provided in general dental practice with the same expected outcomes compared with maintenance that is provided in a specialist clinic, providing that general dentists are given specific instructions regarding the maintenance regimen. A strong emphasis on effective plaque control is necessary.

Analysis of sensitivity and specificity of a new digital subtraction system: an in vitro study

OBJECTIVE

The purpose of this study was to compare a new digital subtraction system with conventional radiograph images for the detection of periapical and periodontal bone lesions.

STUDY DESIGN

Periapical and periodontal bone lesions were simulated with cortical bone chips of varying sizes placed on a human dry mandible. Radiographic film images were acquired from varying projections and were subsequently digitized, registered, and subtracted. Four clinicians evaluated the subtracted images, and sensitivity and specificity were calculated.

RESULTS

The mean sensitivity and specificity of the Diagnostic Subtraction Radiography system for detecting bone lesions of all sizes with varying projection geometry were 87.90% and 85.23%, respectively. The corresponding results for conventional radiograph images were 47.54% and 97.38%. The difference in sensitivity was statistically significant, whereas the difference in specificity was not.

CONCLUSIONS

These results indicate that, even when radiographs are taken from disparate projection geometries, the Diagnostic Subtraction Radiography system is capable of excellent discrimination between healthy and disease states in this in vitro model.