Validation of cone-beam computed tomography as a predictor of osteoporosis using the Klemetti classification

Jawbone quality classification in dental implant planning and placement studies. A scoping review

Aim

Cone beam computed tomography has become an attractive method for implant planning. However, in most cases, not all the information is taken advantage of and often the radiographic evaluation of bone quality is based on subjective assessment by the individual clinician. Therefore, the aim of this study was to examine classifications of bone tissue characteristics and methods for assessing them in dental implant planning and placement studies.

Materials and Methods

Three databases (Pubmed, Scopus, Web of Science) were searched using specific index terms: "Bone quality, bone quantity, bone density, cone-beam CT and cone-beam computed tomography". Three reviewers selected titles and analyzed abstracts according to inclusion and exclusion criteria. Some descriptions of bone tissue characteristics (bone quality, density, and quantity) used before or during dental implant placement were selected and categorized.

Results

The search yielded 442 titles. A total of 32 articles were selected and read in full text. Seventeen articles were considered relevant. Different classification systems were found to evaluate bone tissue characteristics as well as different examination protocols. Thirteen publications included in this review reported on bone quality and quantity using the Lekholm and Zarb classification. However, only four studies implemented and/or proposed modifications of the Lekholm and Zarb system. Four other publications described bone quality according to different classification systems such as Misch, University of California Los Angeles (UCLA), or Trisi and Rao. The assessment methods were often briefly described (or not described at all in one publication). Of the articles analyzed, five presented observer performance, whereas three presented diagnostic accuracy of the assessment method.

Conclusion

Currently, there are different classification systems applied to dental implant planning and placement, particularly regarding whether bone quality or quantity affects treatment outcomes. However, most authors have not validated the diagnostic accuracy and reproducibility of the classification used. Therefore, it is necessary to develop a classification system consistent with characteristics of bone tissue, taking into consideration an adequate description of bone tissue assessment methods, their diagnostic accuracy, and observer performance.

Utility of Cone-Beam Computed Tomography in the Detection of Low Bone Mass-A Systematic Review

INTRODUCTION

Cone-beam computed tomography (CBCT) is widely used in the preoperative qualitative and quantitative assessment of dental implant sites, offering dimensional accuracy, spatial resolution, gray density, and contrast comparable to those of classical CT scan, yet with disputable ability to determine bone mass density.

MATERIALS AND METHODS

A systematic review of the literature was performed using the PubMed and SCOPUS databases, with terms referring to low bone mass and cone-beam computed tomography (CBCT).

RESULTS

Sixteen studies were included in the review. The results show different perspectives, but the evidence favors the use of CBCT, combined with dual-energy X-ray absorptiometry bone density scan (DXA) evaluation, for the assessment of the osteoporosis status of the aging population and, more specifically, in postmenopausal women. Radiographic density (RD) values of the dens and the left part of the first cervical vertebra show the strongest correlation coefficients and the highest sensitivity, specificity, and accuracy for predicting osteoporosis (OP) in the lumbar vertebrae and the femoral neck.

CONCLUSIONS

Our review suggests the potential of CBCT as a screening tool for patients with low bone mass using different radiomorphometric indices. Linear measurements of the inferior mandibular cortex were lower in osteoporotic individuals, indicating the perspective of CBCT also as a diagnostic tool for this disease.

Cone beam computed tomography analysis of mandibular inferior cortical thickness and bone texture in cemento-osseous dysplasia

OBJECTIVE

This study compared mandibular cortical thickness (CTh) and fractal dimension (FD) in patients with cemento-osseous dysplasia (COD) and controls, as measured with cone beam computed tomography.

STUDY DESIGN

In total, 28 female patients with COD and 28 age-matched controls were selected retrospectively. Inferior cross-sectional CTh was measured at the symphysis (sCTh), anterior (aCTh), mental foramen (mfCTh), molar (mCTh), and posterior (pCTh) regions. The alternate measurement of mean CTh of the volume including buccal, lingual, and inferior cortices between the mental foramina (alternate CTh) was measured in ImageJ. FD was calculated in cortical and trabecular bone. Data were analyzed for significance of differences in CTh and FD between patient groups and for correlation of inferior and alternate CTh measurements.

RESULTS

Inferior CTh values were lower overall in the patients with COD than in the controls (P = .01), specifically at sCTh, mCTh, and pCTh (P ≤ .042). Alternate CTh was also significantly lower in the COD group (P = .005). There was a significant correlation between inferior and alternate CTh measurements (r = 0.636, P < .001). No significant differences were observed in cortical or trabecular FD between groups (P ≥ .072).

CONCLUSIONS

Female patients with COD had significantly lower inferior and alternate CTh than healthy controls. Both groups had similar cortical and trabecular bone textures.

Mandibular cortical index in the screening of postmenopausal at low mineral density risk: a systematic review

OBJECTIVES

This systematic literature review addressed the use of mandibular cortical index (MCI), assessed by panoramic radiography, for the identification of postmenopausal women at risk of osteoporosis.

METHODS

Databases were searched for original research studies published from September 2010 to September 2020 using the following keywords: "postmenopausal osteoporosis" and synonyms combined with "panoramic radiography" and synonyms. Only English language manuscripts and studies pertaining to the MCI were selected.

RESULTS

A total of 24 studies were included. The publications were highly heterogeneous in terms of the subject of interest, i.e. the MCI, with some studies comparing the usefulness of the MCI using panoramic radiography and using cone beam computed tomography, and others comparing different radiomorphometric indexes developed for panoramic radiography.

CONCLUSIONS

Based on the literature included in this systematic review, we conclude that the MCI is useful as an auxiliary tool for identifying postmenopausal females at risk of low bone mineral density (BMD), as it correlates with skeletal BMD measured by dual X-ray absorptiometry. Nevertheless, other radiomorphometric indexes obtained from panoramic radiographs, such as panoramic mandibular index, mental index, and mandibular cortical width, are also valuable as auxiliary tools in the identification of postmenopausal females at risk, as they also correlate with BMD. Thus, it is not possible to affirm which index is the most reliable for the identification of postmenopausal females considering the literature screened. PROSPERO registration systematic review CRD42020208152.

A new cone-beam computed tomography-driven index for osteoporosis prediction

OBJECTIVE

To verify whether mandibular cortical analyses accurately distinguish postmenopausal women with normal bone mineral density (BMD) from women with osteoporosis by means of a cone-beam computed tomography (CBCT)-driven composite osteoporosis index (three-dimensional mandibular osteoporosis index-3D MOI).

MATERIAL AND METHODS

The comparison was performed between 52 women with normal BMD and 51 women with osteoporosis according to dual-energy X-ray absorptiometry (DXA) examination of the lumbar spine and hip. Mandibular cortical width (MCW) and cortical quality were evaluated on cross-sectional and panoramic reconstructed images. ANOVA, ROC curves and accuracy measurements were used for statistical analyses, as well as a predictive model combining the quantitative and qualitative analyses and age.

RESULTS

All CBCT-driven measurements presented good to moderate intra- and interobserver agreements. MCW values were significantly lower in women with osteoporosis. Postmenopausal women with osteoporosis were 8 times more likely to have the cortex classified as C3, and 2.4 times more likely to have MCW thinner than 2.75 mm. The area under the ROC curve was 0.8 for the predictive model.

CONCLUSIONS

The newly developed 3D MOI enables distinguishing women with osteoporosis from those with normal BMD with good sensitivity and specificity.

CLINICAL RELEVANCE

Whenever a CBCT scan is performed for specific clinical indications, a 3D MOI may be performed to qualitatively and quantitatively assess the condition of the mandibular cortex. This may be surely helpful to assess the osteoporosis status in the ageing population and more specifically in peri- or postmenopausal women.

Comparison of mandibular index values determined from standard panoramic versus cone beam computed tomography reconstructed images

OBJECTIVE

The aim of this study was to compare mandibular index values, including the mandibular cortical index (MCI), mental index (MI), and panoramic mandibular index (PMI), determined on the basis of cone beam computed tomography (CBCT) and panoramic reconstructed (PR) images.

STUDY DESIGN

PR and CBCT images of 182 patients were retrospectively analyzed. Cross-sectional (CS) and PR images were obtained from CBCT data. The MCI, MI, and PMI were assessed on CS, PR, and panoramic images and evaluated for intra- and interobserver agreements by κ-value or intraclass correlation coefficient (ICC) analysis. Agreement among measurement methods was assessed by using the Bland-Altman method, with CS images as the gold standard for linear measurements.

RESULTS

Measurements from PR and CS images agreed with those from panoramic images in 66.7% and 53.8% of C3 classifications of MCI (porous cortices forming many endosteal residues), respectively. Panoramic and CBCT images exhibited good agreement in MI findings (ICC 0.91) and moderate (PR and panoramic images: ICC 0.79) to good (CS and panoramic images: ICC 0.87) agreement in PMI findings.

CONCLUSIONS

Because of the overlapping of buccal and lingual cortices, panoramic images are especially inadequate for determining the C3 category of MCI. However, CS images obtained from available CBCT data provide better visibility compared with panoramic images and, therefore, can be used for evaluating mandibular indices.

Digital panoramic radiography and cone-beam CT as ancillary tools to detect low bone mineral density in post-menopausal women

OBJECTIVES

To evaluate the usefulness of the mandibular cortical index (MCI) obtained by digital panoramic radiography (DPR) and by panoramic reconstruction (PR) of cone-beam CT (CBCT) with three different slice thicknesses for the screening of low bone mineral density (BMD) in post-menopausal women.

METHODS

Two trained oral and maxillofacial radiologists assessed the MCI based on the morphology of the mandibular bone cortex (classified as C1, C2 or C3). The DPR and PR of CBCT with slice thicknesses of 5, 15 or 25 mm were compared to the BMD obtained by dual-energy X-ray absorptiometry (DXA) in post-menopausal women. Measures related to accuracy were calculated with MedCalc software. The confidence interval was set at 95%.

RESULTS

54 women (mean age 58.70 ± 7.35 years) participated in the study. The sensitivity and specificity values obtained for DPR were 52.6% and 56.2%, respectively, and values for PR of CBCT with 5, 15, and 25 mm slice thicknesses were 63.1% and 43.7%, 50.0% and 50.0%, and 52.6% and 62.5%, respectively. For the tools evaluated, the positive likelihood ratio ranged from 1.00 to 1.40 and negative likelihood ratio from 0.76 to 1.00. The positive predictive value (PPV) ranged from 70.4 to 76.9% and the negative predictive value (NPV) from 29.6 to 35.7%. Among the examinations, the highest value for area under the curve (AUC) was obtained for CBCT with 25 mm slice thickness (57.6%).

CONCLUSIONS

The MCI calculated by DPR and CBCT differed with regard to accuracy. Within the limitations of this study, the PR of CBCT with 25 mm slice thicknesses seems to be the most accurate among the examinations evaluated. Should the dentist be attentive, DPR and CBCT may be useful tools for the screening of low BMD in post-menopausal women, facilitating their timely referral for further assessment.

Computer-based automatic classification of trabecular bone pattern can assist radiographic bone quality assessment at dental implant site

OBJECTIVE:

To develop and validate an automated classification method that determines the trabecular bone pattern at implant site based on three-dimensional bone morphometric parameters derived from CBCT images.

METHODS:

25 human cadaver mandibles were scanned using CBCT clinical scanning protocol. Volumes-of-interest comprising only the trabecular bone of the posterior regions were selected and segmented for three-dimensional morphometric parameters calculation. Three experts rated all bone regions into one of the three trabecular pattern classes (sparse, intermediate and dense) to generate a reference classification. Morphometric parameters were used to automatically classify the trabecular pattern with linear discriminant analysis statistical model. The discriminatory power of each morphometric parameter for automatic classification was indicated and the accuracy compared to the reference classification. Repeated-measures analysis of variances were used to statistically compare morphometric indices between the three classes. Finally, the outcome of the automatic classification was evaluated against a subjective classification performed independently by four different observers.

RESULTS:

The overall correct classification was 83% for quantity-, 86% for structure-related parameters and 84% for the parameters combined. Cross-validation showed a 79% model prediction accuracy. Bone volume fraction (BV/TV) had the most discriminatory power in the automatic classification. Trabecular bone patterns could be distinguished based on most morphometric parameters, except for trabecular thickness (Tb.Th) and degree of anisotropy (DA). The interobserver agreement between the subjective observers was fair (0.25), while the test-retest agreement was moderate (0.46). In comparison with the reference standard, the overall agreement was moderate (0.44).

CONCLUSION:

Automatic classification performed better than subjective classification with a prediction model comprising structure- and quantity-related morphometric parameters.

ADVANCES IN KNOWLEDGE:

Computer-aided trabecular bone pattern assessment based on morphometric parameters could assist objectivity in clinical bone quality classification.

Panoramic radiographs and quantitative ultrasound of the radius and phalanx III to assess bone mineral status in postmenopausal women

Background

Various mandibular indices have been developed to detect osteoporosis on panoramic radiographs. Quantitative ultrasound (QUS) is a low-cost, radiation-free method to assess bone status. The aim of this study was to compare mandibular morphometric analysis and QUS at the radius and proximal phalanx III finger.

Methods

The study involved 97 postmenopausal women, aged 48.5–71.5y (mean: 55.4). Mandibular morphometric analysis comprised: distance between upper and lower mandibular borders just behind the mental foramen (H), distance: mental foramen - inferior mandibular cortex (IM) and mandibular cortical width at the mental region (MCW). Then, ratios were calculated: MCW/IM = PMI (panoramic mandibular index), H/IM = MR (mandibular ratio). Mandibular cortical index (MCI) was used to classify the morphology of the mandibular cortex.

Bone mineral status assessed using QUS at the radius and proximal phalanx III finger was compared to population mean apical bone mass (T-score).

Linear regression analysis was used for correlations between continuous variables, Pearson’s correlation coefficient r - for variables of normal distribution. Student’s t-test was used to compare variables of normal distribution and for the latter - Mann-Whitney U-test. The level of significance was p < 0.05.

Results

Mandibular height was 13.42–34.42 mm. The mean mandibular cortical width was 3.31 mm. Mean values of PMI and MR were 0.33 and 2.57, respectively. Higher mean value of Ad-SoS was found in the radius than in the III finger. Phalanx T-score values ​​were lower than those of the radius. T-score of the radius was < − 1.0 in 22 patients, indicating osteopenia. Basing on phalanx T-score, osteopenia was found in 39 patients. Category C1 of Mandibular Cortical Index was found in 48 women, C2 - in 37 women and C3 - in 12 women. Higher scores of Mandibular Cortical Index were recorded in older women. MCI significantly correlated with the skeletal status (p = 0.01) as well as with H, MCW and MR. Phalanx T-score was not correlated to PMI, MR or MCW.

Conclusions

1. Mandibular Cortical Index can be used as a screening tool for detecting osteoporosis.

2. Quantitative ultrasound at the phalanx III constitutes a reliable way of assessing bone status.

Electronic supplementary material

The online version of this article (10.1186/s12903-018-0593-4) contains supplementary material, which is available to authorized users.