Fractal analysis of the trabecular bone pattern in the presence/absence of metal artifact–producing objects: Comparison of cone-beam computed tomography with panoramic and periapical radiography

Objectives:The effect of metallic objects on the fractal dimension (FD), bone area fraction (BAF) and gray scale values (GSVs) of cone-beam CT (CBCT) images was assessed. Also, FD, BAF and GSV were compared among CBCT, digital periapical and panoramic radiographies.Methods:Digital periapical and panoramic radiographs were acquired from six blocks of bovine rib. Additionally, different arrangements of titanium implants and intracanal metallic posts were created in the bone blocks and CBCT scans were taken from the different implant-root arrangements. The three radiographical modalities were compared by analysis of variance. Pairwise comparisons between the modalities were performed by the Tukey test (significance level set at 0.05).Results:Different root-implant arrangements in the CBCT images revealed no significant differences in the FD (p = 0.920), BAF and GSV values (p = 0.623). FD differed significantly among the three modalities (p < 0.001). Significant differences were found between CBCT and each of the periapical and panoramic techniques (p < 0.001), while no remarkable differences were observed in the FD of the periapical and panoramic images (p = 0.294). BAF and GSV showed significantly different results among the three radiographical techniques (p < 0.001). The difference was remarkable between CBCT and periapical (p < 0.001), CBCT and panoramic (p < 0.001) and periapical and panoramic (p = 0.008).Conclusion:Presence of titanium implants and intracanal posts does not produce different results in the fractal analysis (FA) of the CBCT images. The trabecular bone pattern is best assessed by FA of the periapical radiographs followed by the panoramic and CBCT techniques, respectively.     

Digital orthopantomograms in osteoporosis detection: mandibular density and mandibular radiographic indices as skeletal BMD predictors

Objectives:

To determine the correlation of skeletal bone mineral density (BMD) with mandibular density and mandibular radiographic indices estimated on digital panoramic radiographs.

Methods:

Study comprised 112 female subjects older than 45 years. Digital panoramic radiographs were taken, and patients were referred to densitometric measuring (dual energy X-ray absorptiometry) of BMD in the hip bones and lumbar spine regions (L1–L4). On the radiographs, mandibular bone density was estimated and the following indices were measured by the DIGORA^® software (Soredex, Tuusula, Finland): mental index (MI), gonial index (GI), antegonial index (AI), panoramic mandibular index (PMI) and alveolar crest resorption degree (M/M). Mandibular cortical index (MCI) was visually estimated.

Results:

Mandibular density and visual index MCI are significant predictors of hip and spine BMD. Mandibular density was marked by a significant square trend: it decreased until the age of 54 years and remained constant until the age of 64 years when it started to increase. Significant correlations were found between MI, AI and PMI values and BMD in the hip but not in the lumbar spine region. The GI and M/M values did not show statistically significant correlations with BMD of either region.

Conclusions:

Mandibular bone density and mandibular radiographic indices are useful in detecting patients with decreased BMD. The applicability of orthopantomograms in diagnosing osteoporosis/osteopenia should be recognized as the potential greatest benefit of this everyday diagnostic method in dental practice.     

The evaluation of MCI,MI, PMI and GT on both genders with different age and dental status

Objectives:

The aim of this study was to measure the mandibular cortical index (MCI), mental index (MI), panoramic mandibular index (PMI) and cortical bone thickness in the zone of the gonial angle (GT) in panoramic radiographies from a large sample of males and females and to determine how they relate to patients'' age, gender and dental status.

Methods:

910 panoramic radiographs were obtained and grouped into age, dental status and gender. The MCI, MI, PMI and GT were analysed.

Results:

Remarkable differences were observed for MCI and GT regarding gender, age groups and dental status on both sides (p < 0.05). While age and dental status had an effect on the MI and PMI in females, dental status had an effect on the MI and PMI in males (p < 0.05). Also, gender had an effect on the MI and PMI (p < 0.05).

Conclusions:

The effects of age and tooth loss are different in females and males. In females, the harmful effects of tooth loss and age are more prominent according to the PMI and MI measurements. The effects of age and tooth loss in the GT and MCI measurements are similar, and these indices can be accepted as more reliable in studies including both genders.     

Radiomorphometric indices of the mandible in a British female population

OBJECTIVES: To examine the radiomorphometric indices of the mandible on panoramic radiographs in a population of British female patients, to identify their normal ranges and to investigate their relationships with age, detentition and social class. METHODS: Five indices, cortical width at the gonion (GI) and below the mental foramen (MI), the panoramic mandibular index (PMI), the mandibular cortical index (MCI) and one new index (measurement of cortical width at the antegonion; AI), were measured bilaterally on 500 panoramic radiographs of females by one trained observer. The measurements were analysed for ease of application, repeatability, relationships with age, dentition and social class and interrelationships between the variables. RESULTS: All quantitative indices (GI, MI, PMI, AI), showed a significant, negative correlation with age. MCI showed an age-related distribution. Mandibular dentition exerted a significant influence on some indices, but social class had no influence. Intra-observer repeatability of MI, PMI and AI was fair (precision < 20%) but that for GI was poor. Intra-observer agreement in MCI assessments was excellent. CONCLUSIONS: The age-related changes in mandibular radiomorphometric indices and their variation within each age band lend support to their potential use in identification of skeletal osteopenia. However, problems with repeatability and measurement precision identified in the pilot study, notably with GI, may be a considerable obstacle to their use in general practice.     

Lingual and buccal mandibular bone depressions: a review based on 583 cases from a world-wide literature survey,including 69 new cases from Japan

OBJECTIVES: To review present knowledge of so-called lingual and buccal mandibular bone depressions (n = 583) based on studies of 247 contemporary and 267 archaeological cases from a world-wide literature survey in addition to 69 new cases from Japan. METHODS: The 69 cases from Japan were retrieved through examination of 42,600 consecutive panoramic radiographs. RESULTS: Bone depressions can be divided into four topographical variants: (1) lingual anterior mandibular body (incisor-canine- premolar area) above the mylohyoid muscle; (2) posterior to the mandibular angle-first permanent molar area, below the mandibular canal, and a third located to the ascending, lingual mandibular ramus, posterior to the lingual foramen, just below the neck of the condyle. An excessively rare fourth variant is located to the buccal aspects of the ascending mandibular ramus. CONCLUSIONS: The present concept favours that all variants have a common origin: a hyperplastic/hypertrophic lobe (or aberrant lobe) of the sublingual, submandibular or parotid salivary gland, exerting pressure upon the cortex of the mandible by the respective gland, leading to focal atrophy or resorption of the bone. The bone depressions take years to develop, appearing radiographically not until the 5th to 6th decades.     

Comparison of antegonial index,mental index,panoramic mandibular index and mandibular cortical index values in the panoramic radiographs of normal males and male patients with osteoporosis

Objective

The aim of the study was to compare the values of the antegonial index (AI), mental index (MI), panoramic mandibular index (PMI) and mandibular cortical index (MCI) in the panoramic radiographs of normal males and male patients with osteoporosis.

Methods

In panoramic radiographs obtained from 40 male individuals (20 normal and 20 with osteoporosis), the mean was calculated for MI, AI, PMI and MCI index values measured in the right and left mandibles. The MI, AI and PMI index values were evaluated using the paired t-test, and MCI values were analysed using the χ² test.

Results

MI (P < 0.001), AI (P < 0.01) and PMI (P < 0.05) values were significantly smaller in the group with osteoporosis; however, MCI (P > 0.05) was not significantly different.

Conclusion

MI, PMI and AI values, as radiomorphometric indices, were found to be smaller among male patients with osteoporosis, compared with normal patients in this study. It is suggested that these indices, used as an ancillary method in the diagnosis of osteoporosis in women, could also be useful for male patients. Further studies, of larger groups are needed on this subject, including of the MCI, which in this study showed no significant difference.     

Comparison of dental and skeletal indices between patients under haemodialysis and peritoneal dialysis with healthy individuals in digital panoramic radiography

Objective:The aim was to compare dental and skeletal indices in panoramic radiography between patients undergoing haemodialysis, peritoneal dialysis and age- and sex-matched control group.Methods:In this comparative cross-sectional study, quantitative Indices including Antegonial Index (AI), Mental Index (MI), Panoramic Mandibular Index (PMI) and qualitative indices including Mandibular Cortical Index (MCI) and Trabecular Pattern (TP) were evaluated in panoramic images of 32 haemodialysis patients, 14 patients under peritoneal dialysis and 52 healthy individuals. The images were also investigated for pulp canal calcification, pulp stones, soft tissue calcification, changes in or loss of lamina dura, radiolucencies associated with brown tumour and ridge resorption. The indices were compared between the three groups and were investigated for association with the patients’ blood test parameters and their diseases causing chronic renal failure (CRF). Intraobserver agreement for the 2-week interval of assessment was calculated for the indices.ResultsMI (p = 0.574) and PMI (p = 0.100) were not significantly different, but AI (p = 0.01), MCI (p < 0.001) and TP (p = 0.002) were significantly different between the two case groups and the control group. The prevalence of pulp calcification (p = 0.03) and ridge resorption (p = 0.005) was higher in the haemodialysis group. Soft tissue calcification (p = 0.85) and lamina dura changes (p = 0.9) showed no significant difference. Brown tumours were observed in only one case in the haemodialysis group.Conclusions:AI, MCI and TP showed a reduction in mineral density of the cortical and trabecular bone in CRF patients and more severely in patients under haemodialysis than those under peritoneal dialysis.     

Detecting young Japanese adults with undetected low skeletal bone density using panoramic radiographs

Objective

The cortical width below the mental foramen of the mandible determined from panoramic radiographs is a useful screening tool for identifying elderly individuals with a low skeletal bone mineral density (BMD). However, whether the mandible cortical width (MCW) is useful for identifying a low skeletal BMD in men and women of 40 years or younger is not known.

Methods

The BMD of the calcaneus was measured by ultrasonography bone densitometry in 158 men and 76 women aged 18–36 years. A logistic regression analysis adjusted for age was used to calculate the odds ratios and 95% confidence interval (CI) of having a low calcaneal BMD, according to the quartiles of the MCW. The areas under the receiver operator characteristic curve (AUC) for identifying participants with a low calcaneal BMD using the MCW were assessed to evaluate the diagnostic efficacy of the MCW.

Results

In men, the adjusted odds ratios of a low calcaneal BMD associated with the second, third and lowest quartiles of MCW were 5.66 (95% CI, 0.61–52.23), 5.43 (95% CI, 0.59–50.18) and 33.22 (95% CI, 3.97–276.94), respectively, compared with the highest quartile, while no significant trend in the adjusted odds ratios was observed in women. The AUC for identifying participants with a low calcaneal BMD based on the MCW was 0.796 (95% CI, 0.702–0.890) in men and 0.593 (95% CI, 0.398–0.788) in women.

Conclusion

MCW determined from panoramic radiographs can be used to identify undetected low calcaneus BMD in young adult men, but not in young adult women.     

Diagnostic efficacy of alveolar bone loss of the mandible for identifying postmenopausal women with femoral osteoporosis

OBJECTIVES: Mandibular cortical width (MCW) detected on panoramic radiographs may be useful for identifying postmenopausal women with osteoporosis. There is little known regarding whether alveolar bone loss (ABL) of the mandible detected on panoramic radiographs is a potentially accurate screening tool for osteoporosis in comparison with MCW. The purpose of this study was to evaluate whether ABL of the mandible on panoramic radiographs is useful for identifying femoral osteoporosis in postmenopausal women in comparison with MCW. METHODS: Three hundred and fifty-four Japanese postmenopausal women (mean age+/-SD, 56.8+/-7.7 years) were recruited for this study. Femoral BMD was measured by dual energy X-ray absorptiometry. Panoramic radiographs were obtained to estimate ABL of the mandible and MCW. RESULTS: A multiple regression analysis revealed that femoral BMD was significantly associated with MCW (P<0.001), weight (P<0.001), age (P<0.001) and ABL of the mandible (P=0.029; adjusted r(2)=0.380). The area under the ROC curve (AUC) for identifying femoral osteoporosis was 0.609 [95% confidence interval (CI), 0.523-0.696] for ABL of the mandible and 0.779 (95% CI, 0.713-0.844) for MCW, respectively. AUC for ABL of the mandible indicated less accuracy. CONCLUSIONS: Our results suggest that ABL of the mandible on panoramic radiographs may not be useful for identifying postmenopausal women with femoral osteoporosis in comparison with MCW.     

The association between carotid calcium on dental panoramic radiographs and coronary calcium score on chest computerized tomography

Objectives:Coronary artery calcium measured by CT predicts future coronary events. Similarly, carotid artery calcium on dental panoramic radiographs has been associated with increased cardiovascular events. Pre-procedural assessment of candidates for valve replacement in our institution includes panoramic radiographs and chest tomography. We aimed to assess the association of carotid calcium on panoramic radiographs with coronary artery calcium on chest tomography.Methods:Paired pre-procedural panoramic radiographs and chest tomography scans were done in 177 consecutive patients between October 2016 and October 2017. Carotid calcium was quantified using NIH’s ImageJ. Coronary artery calcium was quantified by the Agatston score using Philips Intellispace portal, v. 8.0.1.20640.Results:Carotid calcium maximal intensity, area and perimeter were higher among patients with high coronary artery calcium. Non-zero carotid calcium was found in half of patients with high coronary artery calcium, doubling prevalence of low coronary artery calcium.Conclusion:Carotid calcium identified in panoramic radiographs was associated with high coronary artery calcium. Awareness of carotid calcium recognized by dental practitioners in low-cost, low radiation and commonly done panoramic radiographs may be useful to identify patients at risk of coronary disease with potential future cardiovascular events.     

Soft tissue lipoma with the radiographic appearance of a neoplasm within the mandibular canal

Lipomas and lipoma variants are common soft tissue tumours but are not commonly found in the oral and maxillofacial region. We report a case of a classic lipoma located on the medial aspect of the mandibular ramus, but not within bone, first seen by an oral and maxillofacial surgeon during treatment planning for routine extractions. Initial panoramic radiography indicated an expansive tumour in the area of the mandibular foramen and proximal end of the mandibular canal, apparently within the body of the mandible. Subsequent imaging with CT revealed a well-circumscribed soft tissue tumour on the medial aspect of the left mandibular ramus, not within the bone itself. Histological analysis of the operative specimen indicated a classic lipoma.     

Fractal dimension on dental radiographs

OBJECTIVES: (1) To compare fractal dimension (FD) from periapical radiographs with FD from panoramic radiographs; (2) to correlate FD with cortical thickness and morphology; and (3) to correlate FD with a reported history of osteoporotic fractures. METHODS: Information on fracture and smoking history was obtained by a telephone interview with 281 elderly (>60 years of age) patients who had periapical and panoramic radiographs exposed on the same date. FD was measured in several locations on both types of radiograph. Mandibular cortical thickness and morphology were obtained from the panoramic radiograph. RESULTS: FD measured in the mandible was lower than FD in the maxilla. Same-jaw measurements had a higher correlation than same-side measurements. FD measured on panoramic radiographs was lower than FD from periapical radiographs. There was a negative correlation between cortical thickness and FD. FD was higher in subjects with more mandibular cortical porosities and resorption. The mean panoramic FD from subjects with a history of osteoporotic fractures was significantly higher, after adjusting for smoking, gender, age, height and weight. CONCLUSIONS: FD measured on panoramic radiographs is lower than FD measured on periapical radiographs. FD is higher in both types of radiograph in subjects with a thinner, severely eroded mandibular cortex and a history of osteoporotic fractures. This study confirms other reports that FD increases when bone mass decreases. In addition, it suggests that panoramic radiographs can be used as a possible alternative for the measurement of FD to periapical radiographs.     

Fractal dimension evaluation of cone beam computed tomography in patients with bisphosphonate-associated osteonecrosis

Objectives

The aim of this study was to (1) evaluate the fractal dimension (FD) in regions of the mandible on cone beam CT (CBCT) images of patients with bisphosphonate-associated osteonecrosis of the jaws (BP-ONJ) and (2) to select the most suitable region of interest (ROI) for further study on detection of bone alterations associated with bisphosphonates.

Methods

CBCT images of patients with BP-ONJ were included with matched controls. Values of FD were compared between groups. Selected ROIs were: ROI-1 — below the mandibular foramen; ROI-2 — above the mandibular foramen; ROI-3 — anterior to the mental foramen; ROI-4 — above the mandibular canal. The area of bone exposure was included as ROI-5. The results were analysed using generalized estimating equations and conditional logistic regression.

Results

There were 36 patients (67% female) with a mean age of 60.7 years. The mean FDs were: ROI-1 — 1.678 for controls and 1.673 for patients (P = 0.81); ROI-2 — 1.657 for controls and 1.653 for patients (P = 0.78); ROI-3 — 1.661 for controls and 1.684 for patients (P = 0.17); and ROI-4 — 1.670 for controls and 1.698 for patients (P = 0.03). The value of the FD in the area of exposed bone was the highest (1.729). The odds of being a BP-ONJ patient vs being a control was six times as high for individuals with a higher FD score at ROI-4, although the confidence interval was quite wide owing to the small sample size.

Conclusion

In this preliminary study, BP-ONJ patients had higher FD values than controls at regions close to the alveolar process. The results suggest that FD is a promising tool for detection of bone alterations associated with BP-ONJ.     

Assessment of bone mineral density in the jaws and its relationship to radiomorphometric indices

Objectives

The aim of this study was to evaluate maxillary, mandibular and femoral neck bone mineral density using dual energy X-ray absorptiometry (DXA) and to determine any correlation between the bone mineral density of the jaws and panoramic radiomorphometric indices.

Methods

49 edentulous patients (18 males and 31 females) aged between 41 and 78 years (mean age 60.2 ± 11.04) were examined by panoramic radiography. Bone mineral density (BMD) of the jaws and femoral neck was measured with a DXA; bone mineral density was calculated at the anterior, premolar and molar regions of the maxilla and mandible.

Results

The mean maxillary molar BMD (0.45 g cm⁻²) was significantly greater than the maxillary anterior and premolar BMD (0.31 g cm⁻², P < 0.05). Furthermore, the mean mandibular anterior and premolar BMD (1.39 g cm⁻² and 1.28 g cm⁻², respectively) was significantly greater than the mean mandibular molar BMD (1.09 g cm⁻², P < 0.01). Although BMD in the maxillary anterior and premolar regions were correlated, BMD in all the mandibular regions were highly correlated. Maxillary and mandibular BMD were not correlated with femoral BMD. In addition, mandibular cortical index (MCI) classification, mental index (MI) or panoramic mandibular index (PMI) values were not significantly correlated with the maxillary and mandibular BMDs (P > 0.05).

Conclusions

The BMD in this study was highest in the mandibular anterior region and lowest in the maxillary anterior and premolar regions. The BMD of the jaws was not correlated with either femoral BMD or panoramic radiomorphometric indices.     

The effects of location of alveolar crest on the vertical bone heights on panoramic radiographs

Objectives

This study aimed to show that the horizontal relationship between the mandibular canal and the alveolar crest can influence the available bone height (ABH) measurement on panoramic radiographs.

Methods

92 mandibular edentulous sites of panoramic computed radiographs and reformatted CT images of 77 patients were used. Selected CT images were categorized into four types according to the relative location of the peak of the alveolar crest to the mandibular canal. One oral and maxillofacial radiologist measured the ABH twice on both imaging modalities with an interval of 7 days and compared the measurement differences according to the type.

Results

The absolute average value of the differences in measurement between the values of ABHs on panoramic images and CT images was 0.97 mm. Significant difference was found only between the mean values of ABHs for Type 1 (0.60 mm), where the alveolar crest is located in the buccal side or central area with respect to the mandibular canal, and Type 4 (1.46 mm), where the alveolar crest is in the lingual side to the mandibular canal (p < 0.05).

Conclusions

The relative horizontal location of the alveolar crest with respect to the mandibular canal affected the ABH measurement on panoramic radiographs. In particular, ABH is overestimated when there has been resorption of the buccal aspect of the ridge, moving the alveolar crest lingually.     

Computed tomography appearance of mandibular para-radicular third molar radiolucencies

Objectives

Mandibular para-radicular third molar radiolucencies (MPRs) were first described in 2004 by Bohay et al (Bohay RN, Mara TW, Sawula KW, Lapointe HJ. A preliminary radiographic study of mandibular para-radicular third molar radiolucencies. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004; 98: 97–101) as a well-defined oval radiolucency surrounded by a thin sclerotic border located immediately distal to the mandibular third molar roots. Bohay et al''s analysis was undertaken using panoramic radiographs. The purpose of this study was to confirm Bohay et al''s findings on panoramic radiographs and to identify and document the appearance of MPRs on cross-sectional CT.

Methods

Panoramic films and CT images of the lower third molar regions from 143 patients were reviewed.

Results

MPR was identified on panoramic film in 12 patients with a total of 14 MPRs. A number of factors were recorded from panoramic films and CT.

Conclusions

This study confirmed the findings of Bohay et al and concluded that the relative lucent appearance on panoramic radiographs can be explained by the presence of one or a combination of factors: (i) an area of decreased density in trabecular bone, (ii) thinning of the inner surface of the buccal cortex, (iii) thinning of the inner surface of the lingual cortex or (iv) a depression in the external surface of the lingual cortex.     

Mandibular ramus-related Stafne's bone cavity

Mandibular bone depressions located on the lingual/buccal aspect of the mandibular ramus are the rarest variants of the so-called Stafne's bone cavities, or major salivary gland-related depressions, with only 17 cases reported in the literature including both clinical cases and archaeological specimens. We report the case of a 14-year-old male patient who sought clinical assistance complaining of a hard expansion on the lower left premolar-molar region. Apart from a unilocular radiolucent lesion between the lower left second premolar and first molar, a panoramic radiograph showed another radiolucent lesion located in the right mandibular ramus, at the level of the mandibular foramen. Computed tomography (CT) revealed an expansile lesion in the left mandibular body, later diagnosed as a simple bone cyst through surgical exploration. The three-dimensional CT volume rendering reconstructed image showed that the second lesion, located on the lingual aspect of the ascending ramus, was an actual cortical bone defect, which was diagnosed as a mandibular ramus-related Stafne's bone cavity. Considering the young age of the patient, the size of the defect, the recognizedly slow development of mandibular bone defects and, above all, the location of the bone defect under discussion, we believe it to have a congenital rather than a developmental origin (i.e. it was caused by a focal failure during intramembranous ossification of the mandible). If this is the case, mandibular bone depressions should not be seen exclusively as salivary gland-related bone defects.     

The differences in panoramic mandibular indices and fractal dimension between patients with and without spinal osteoporosis

OBJECTIVES: The aims of this study were to evaluate the relationship between osteoporosis, oral signs, body mass index and age; and to assess the possibility of using these parameters as an indicator of post-menopausal osteoporosis. The oral signs were panoramic-based mandibular indices, such as cortical width, cortical index, panoramic mandibular index and mandibular crest resorption degree; the number of teeth and fractal dimension analysis. METHODS: Forty-eight post-menopausal women between the ages of 40 years and 64 years were evaluated. Mandibular indices and the number of mandibular teeth were measured and evaluated from panoramic radiographs and fractal dimension was calculated from the direct digital periapical radiographs of the mandibular premolar-molar region in box-counting method. Weight, height, menopausal status and age of the patients were recorded by questionnaire. Bone mineral densities of the patients were measured with dual energy X-ray absorptiometry. RESULTS: In this study there were no statistically significant differences between the osteoporotic and non-osteoporotic patients for cortical width, panoramic mandibular index, alveolar crest resorption degree, fractal dimension and the number of mandibular teeth, but there was a difference for cortical index. Binary logistic regression analyses demonstrated that age (P = 0.015) was an important risk factor for osteoporosis. CONCLUSION: The results of this study demonstrated that osteoporotic patients were more likely to have altered inferior cortex morphology than non-osteoporotic patients and age is an important risk factor for osteoporosis.     

Application of panoramic radiography with a multilayer imaging program for detecting proximal caries: a preliminary clinical study

Objective:The aim of this study is to introduce a novel program of panoramic radiography that shows 41 multilayer images from the buccal to lingual aspects in a region of interest, and to evaluate the effectiveness of this program for detecting proximal caries.Methods:In total, 480 premolars and molars on 30 panoramic radiographs taken with the multilayer imaging program were included in this study. The presence or absence of caries in 960 proximal surfaces was assessed by three experienced oral and maxillofacial radiologists as a consensus-based gold-standard. Two general dentists evaluated and scored proximal caries on 980 surfaces on panoramic radiographs with and without the multilayer imaging program. The two general dentists’ scores were compared with the gold-standard, and were analyzed for sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating characteristic (ROC) curve with and without using the program. The area under the ROC curve was analyzed using STATA/SE 13.1.Results:When the multilayer imaging program was used for panoramic radiography, the inter- and intraobserver agreement of the two general dentists improved. All values, including the area under the ROC curve, were higher when the multilayer imaging program was used than when it was not used. The area under the ROC curve showed a statistically significant improvement only in Observer 1, whose diagnostic ability was poorer than that of Observer 2.Conclusions:oThis multilayer imaging program might help the inexperienced dentist to improve the diagnostic accuracy of proximal caries. If further studies would be performed in various clinical application, it could be useful when intraoral radiography taking is difficult for reasons such as mouth-opening limitations and the gag reflex of the patients.