Use of artificial intelligence software in dental education: A study on assisted proximal caries assessment in bitewing radiographs.

INTRODUCTION: Teaching of dental caries diagnostics is an essential part of dental education. Diagnosing proximal caries is a challenging task, and automated systems applying artificial intelligence (AI) have been introduced to assist in this respect. Thus, the implementation of AI for teaching purposes may be considered. The aim of this study was to assess the impact of an AI software on students' ability to detect enamel-only proximal caries in bitewing radiographs (BWs) and to assess whether proximal tooth overlap interferes with caries detection. MATERIALS AND METHODS: The study included 74 dental students randomly allocated to either a test or control group. At two sessions, both groups assessed proximal enamel caries in BWs. At the first session, the test group registered caries in 25 BWs using AI software (AssistDent®) and the control group without using AI. One month later, both groups detected caries in another 25 BWs in a clinical setup without using the software. The student's registrations were compared with a reference standard. Positive agreement (caries) and negative agreement (no caries) were calculated, and t-tests were applied to assess whether the test and control groups performed differently. Moreover, t-tests were applied to test whether proximal overlap interfered with caries registration. RESULTS: At the first and second sessions, 56 and 52 tooth surfaces, respectively, were detected with enamel-only caries according to the reference standard. At session 1, no significant difference between the control (48%) and the test (42%) group was found for positive agreement (p = .08), whereas the negative agreement was higher for the test group (86% vs. 80%; p = .02). At session 2, there was no significant difference between the groups. The test group improved for positive agreement from session 1 to session 2 (p < .001), while the control group improved for negative agreement (p < .001). Thirty-eight per cent of the tooth surfaces overlapped, and the mean positive agreement and negative agreement were significantly lower for overlapping surfaces than non-overlapping surfaces (p < .001) in both groups. CONCLUSION: Training with the AI software did not impact on dental students' ability to detect proximal enamel caries in bitewing radiographs although the positive agreement improved over time. It was revealed that proximal tooth overlap interfered with caries detection.

Assessment of YOLOv3 for caries detection in bitewing radiographs based on the ICCMS™ radiographic scoring system.

OBJECTIVES: To assess the feasibility of the YOLOv3 model under the intersection over union (IoU) thresholds of 0.5 (IoU50) and 0.75 (IoU75) for caries detection in bitewing radiographs based on the International Caries Classification and Management System (ICCMS™). MATERIALS AND METHODS: We trained the YOLOv3 model by feeding 994 annotated radiographs with the IoU50 and IoU75 thresholds. The testing procedure (n = 175) was subsequently conducted to evaluate the model's prediction metrics on caries classification based on the ICCMS™ radiographic scoring system. RESULTS: Regarding the 4-class classification representing caries severity, YOLOv3 could accurately detect and classify enamel caries and initial dentin caries (class RA) (IoU50 vs IoU75: precision, 0.75 vs 0.71; recall, 0.67 vs 0.64). Concerning the 7-class classification signifying specific caries depth (class 0, healthy tooth; classes RA1-3, initial caries affecting outer half, inner half of enamel, and the outer 1/3 of dentin; class RB4, caries extending to the middle 1/3 of dentin; classes RC5-6, extensively cavitated caries affecting the inner 1/3 of dentin and involving the pulp chamber), YOLOv3 could accurately detect and classify caries with pulpal exposure (class RC6) (IoU50 vs IoU75: precision, 0.77 vs 0.73; recall, 0.61 vs 0.57) but it failed to predict the outer half of enamel caries (class RA1) (IoU50 vs IoU75: precision, 0.35 vs 0.32; recall, 0.23 vs 0.21). CONCLUSIONS: YOLOv3 yielded acceptable performances in both IoU50 and IoU75. Although the performance metrics decreased in the 7-class detection, the two thresholds revealed comparable results. However, the model could not consistently detect initial-stage caries affecting the outermost surface of the enamel. CLINICAL RELEVANCE: YOLOv3 could be implemented to detect and classify dental caries according to the ICCMS™ classification with acceptable performances to assist dentists in making treatment decisions.

Validity of near-infrared light transillumination for the assessment of proximal caries in permanent teeth.

PURPOSE: The aim of this study was to evaluate the performance of DIAGNOcam (DC) in diagnosing proximal caries and to compare its effectiveness with the International Caries Detection and Assessment System (ICDAS) and bitewing radiography (BWR). METHODS: 118 premolars extracted for orthodontic reasons were included and examined using three detection methods and validated by histological sections as the gold standard. The sensitivity, specificity and areas under the ROC curve (Az value) at the outer half enamel (D1), inner half enamel (D2) and dentine (D3) thresholds were compared between different methods. RESULTS: At all categories, the specificity of DC was almost as high as ICDAS and BWR. DC showed a significantly higher sensitivity (0.68) than both visual (0.33) and radiographic examination (0.47) at the D1 threshold. DC presented the highest Az value (area under the ROC curve) at the D1 and D2 threshold (0.81, 0.86), while BWR showed the greatest Az values at D3 (0.94). Furthermore, DC had the highest association strength with the gold standard (Spearman's ρ = 0.80). CONCLUSIONS: It can be concluded that DC could detect proximal caries effectively and showed comparable or even better performance than ICDAS and BWR.

Simulation of three intraoral radiographic techniques in pediatric dental patients: subjective comfort assessment using the VAS and Wong-Baker FACES Pain Raiting Scale.

BACKGROUND: Perception of pain associated with intraoral radiography in pediatric patients was evaluated through statistical comparisons of data obtained using the Wong-Baker FACES Pain Raiting Scale (WBFPRS) and visual analog scale (VAS) scoring. METHODS: A total of 75 pediatric patients aged 6-12 years were included in this study. Simulations of each of three radiological methods (analog films, CCD sensor and phosphorus plates) were performed on 25 pediatric patients. Following the simulations, the meaning of each facial expression on the WBFPRS and the numbers on the VAS were explained to each child. For the comparison between groups, the homogeneity of the variances was tested with Levene's test; because the variances were not homogeneous, Welch's test was used. Tamhane's T2 test was used because the homogeneity assumption was not provided to determine the source of the difference between the groups. RESULTS: When the conventional method was compared to the PSPL (photostimulable phosphor luminescence) method, no significant differences were noted in either the WBFPRS or VAS results (p >0.05). The results obtained from both of the scales were significantly different between the conventional method and the CCD sensor method (p < 0.05). When the PSPL and CCD sensors were compared, a significant difference was observed for the WBFPRS (p < 0.05). It was found the highest level of pain scores when used the CCD sensor method than the analog film and PSPL methods (p < 0.05). CONCLUSIONS: It is expected that digital radiographic techniques will be improved in the future and that their disadvantages will be eliminated, resulting in imaging devices that are more comfortable for pediatric patients.

Assessment of three methods of geometric image reconstruction for digital subtraction radiography.

OBJECTIVES: To evaluate three methods of geometric image reconstruction for digital subtraction radiography (DSR). METHODS: Digital periapical radiographs were acquired of 24 teeth with the X-ray tube at 6 different geometric configurations of vertical (V) and horizontal (H) angles: V0°H0°, V0°H10°, V10°H0°, V10°H10°, V20°H0° and V20°H10°. All 144 images were registered in pairs (Group V0°H0° + 1 of the 6 groups) 3 times by using the Emago(®) (Oral Diagnostic Systems, Amsterdam, Netherlands) with manual selection and Regeemy with manual and automatic selections. After geometric reconstruction on the two software applications under different modes of selection, all images were subtracted and the standard deviation of grey values was obtained as a measure of image noise. All measurements were repeated after 15 days to evaluate the method error. Values of image noise were statistically analyzed by one-way ANOVA for differences between methods and between projection angles, followed by Tukey's test at a level of significance of 5%. RESULTS: Significant differences were found between most of the projection angles for the three reconstruction methods. Image subtraction after manual selection-based reconstruction on Regeemy presented the lowest values of image noise, except on group V0°H0°. The groups V10°H0° and V20°H0° were not significantly different between the manual selection-based reconstruction in Regeemy and automatic selection-based reconstruction in Regeemy methods. CONCLUSIONS: The Regeemy software on manual mode revealed better quality of geometric image reconstruction for DSR than the Regeemy on automatic mode and the Emago on manual mode, when the radiographic images were obtained at V and H angles used in the present investigation.

Assessment of intraoral image artifacts related to photostimulable phosphor plates in a dentomaxillofacial radiology department.

OBJECTIVE: The aim of the present study was to evaluate the presence, frequency, and causes of artifacts in intraoral images obtained using photostimulable phosphor (PSP) plates. MATERIALS AND METHODS: A total of 11,443 intraoral images, including 4291 periapical and 7152 bitewing images, acquired over a 6-month period as well as over a month 1-year after the initial imaging were evaluated by a single observer and image artifacts only related to the PSP system were recorded. Before the study, an experienced dentomaxillofacial radiologist and a research assistant assessed a set of image artifacts and agreed on the causes of these artifacts. All unidentified artifacts were reassessed by both researchers before the final decision. The data were analyzed using the statistical software SPSS 11.5. RESULTS: The total number of images with one or more artifacts was 2344 (20.4%). Of these, 2008 were of adult patients and 336 were of pediatric patients. While movement of the phosphor plate in the disposable pocket was the most common cause of the observed image artifacts in the children, non-uniform image brightness was the most frequently observed artifact in the case of the adults. CONCLUSION: The percentage of images with artifacts in the 6th month was lower than that during the 1st month. More significantly, the lowest percentage was obtained 1-year after the initial imaging, owing to the increase in familiarity with the system. Understanding the reasons for the image artifacts and studying ways of preventing are of high clinical importance.

Concrescence: assessment of case by periapical radiography, cone beam computed tomography and micro-computed tomography.

The aim of this article was to describe imaging aspects of concrescence analyzed by three imaging modalities. A second molar joined together with a third molar was imaged using digital periapical radiography, cone beam computed tomography (CBCT) and micro-computed tomography (Micro-CT). On periapical radiograph, the mesial root of the third molar is superimposed on the distal root of the second molar. On CBCT images, a large cementum union between bulbous roots was detected, confirming the diagnosis of concrescence. On micro-CT images, the cementum union appeared limited to the apical third of the roots. In conclusion, both computed tomography modalities allowed for the diagnosis of concrescence. However, only micro-CT provided the real extension of the cementum union.

Oblique lateral radiographs and bitewings; estimation of organ doses in head and neck region with Monte Carlo calculations.

OBJECTIVES: When bitewing radiographs are not possible (e.g. patients with special needs), oblique lateral radiographs may offer an alternative. The aims of this study were to assess the impact of horizontal projection angulation, focus-to-skin distance, exposure time and age of the patient on the equivalent radiation dose of several organs in the head and neck region by means of personal computer X-ray Monte Carlo (PCXMC) calculations and to assess the dose obtained from conventional bitewing radiographs. METHODS: PCXMC v. 2.0 software (STUK(®), Helsinki, Finland) was used to estimate the equivalent radiation doses and the total effective dose. Three exposure times, five age categories, two focus-to-skin distances and eight horizontal geometric angulations were assumed. The organs involved were the thyroid gland, oesophagus, salivary glands, bone marrow, oral mucosa, skull, cervical spine and skin. A similar calculation was also performed for bitewings taken with a rectangular collimator. Results and conclusion Bitewings taken with rectangular collimation decrease the radiation burden of the patient to 50%, compared with circular collimation. In the oblique lateral radiographs, focus-to-skin distance, patient's age and beam collimation had a significant impact on the equivalent doses measured in this study. Exposure time had a significant impact on the equivalent doses of the salivary glands, oral mucosa, skull and skin. Horizontal angulations had a significant impact on the equivalent doses of the thyroid gland, bone marrow, oral mucosa, skull and cervical spine. The total effective radiation dose was significantly influenced by all parameters investigated in this study.

Nerve damage assessment following implant placement in human cadaver jaws: an ex vivo comparative study.

The present study compared the use of cone beam computerized tomography (CBCT) images and intra-oral radiographs in the placement of final implant drills in terms of nerve damage to cadaver mandibles. Twelve cadaver hemimandibles obtained from 6 cadavers were used. Right hemimandibles were imaged using peri-apical radiography and left hemimandibles using CBCT, and the images obtained were used in treatment planning for the placement of implant drills (22 for each modality, for a total of 44 final drills). Specimens were dissected, and the distances between the apex of the final implant drill and the inferior alveolar neurovascular bundle and incisive nerve were measured using a digital calliper. Nerves were assessed as damaged or not damaged, and the Chi-square test was used to compare nerve damage between modalities (P < 0.05). Nerve damage occurred with 7 final drills placed based on peri-apical radiography (31.8%) and 1 final drill placed using CBCT images (4.5%). The difference in nerve damage between imaging modalities was statistically significant (P = 0.023), with CBCT outperforming intraoral film in the placement of final implant drills ex vivo. In order to prevent nerve damage, CBCT is recommended as the principal imaging modality for pre-implant assessment.

Contemporary management of horizontal root fractures to the permanent dentition: diagnosis--radiologic assessment to include cone-beam computed tomography.

Historically, obtaining several periapical radiographs has been recommended to diagnose horizontal root fractures. Assessing the 3-dimensional orientation of a fracture is correlated to treatment and outcome. However, conventional radiography yields only limited information for accurate diagnosis. Cone-beam computed tomography (CBCT) is a relatively new and useful technology, which provides an auxiliary imaging modality to supplement conventional radiography for evaluating horizontal root fractures. Despite the increasing application of this technology as well as a growing body of evidence supporting its value in diagnosing horizontal root fractures, there are no specific guidelines for its use. This article aimed to provide such preliminary guidelines for cases of suspected horizontal root fracture as a result of trauma. From a database search it was concluded that CBCT is most useful in cases in which conventional radiography yields inconclusive results or shows a fracture in the middle third of a root. In such cases CBCT may rule out false negatives, ie, a suspected root fracture not visualized with conventional radiography. For a root fracture in the middle third, CBCT may rule out or confirm an oblique course of fracture involving the cervical third in the labiolingual dimension. Although there are considerable advantages when CBCT is included in the assessment of horizontal root fracture and its possible sequelae, more experimental and clinical studies are warranted to determine the exact impact on outcomes.

Ultrashort echo time (UTE) MRI for the assessment of caries lesions.

OBJECTIVE: Direct in vivo MRI of dental hard tissues by applying ultrashort echo time (UTE) MRI techniques has recently been reported. The objective of the presented study is to clinically evaluate the applicability of UTE MRI for the identification of caries lesions. METHODS: 40 randomly selected patients (mean age 41 ± 15 years) were enrolled in this study. 39 patients underwent a conventional clinical assessment, dental bitewing X-ray and a dental MRI investigation comprising a conventional turbo-spin echo (TSE) and a dedicated UTE scan. One patient had to be excluded owing to claustrophobia. In four patients, the clinical treatment of the lesions was documented by intraoral pictures, and the resulting volume of the cavity after excavation was documented by dental imprints and compared with the MRI findings. RESULTS: In total, 161 lesions were identified. 157 (97%) were visible in the UTE images, 27 (17%) in the conventional TSE images and 137 (85%) in the X-ray images. In total, 14 teeth could not be analysed by MR owing to artefacts caused by dental fillings. All lesions appear significantly larger in the UTE images as compared with the X-ray and TSE images. In situ measurements confirm the accuracy of the lesion dimensions as observed in the UTE images. CONCLUSION: The presented data provide evidence that UTE MR imaging can be applied for the identification of caries lesions. Although the current data suggest an even higher sensitivity of UTE MRI, some limitations must be expected from dental fillings.

New attempts to modify periodontal risk assessment for generalized aggressive periodontitis: a retrospective study.

BACKGROUND: Periodontal risk assessment (PRA) model was designed for risk evaluation of treated patients with periodontal disease. However, its use on generalized aggressive periodontitis (GAgP) had been scarcely reported. This study aims to investigate the association of original PRA/modified PRA (MPRA) and compliance of periodontal maintenance with long-term treatment outcomes of Chinese patients with GAgP. METHODS: Eighty-eight patients from a GAgP cohort, who completed active periodontal treatment (APT) and accepted reevaluation 3 to 11 years (mean of 5.5 years) afterward, were enrolled. PRA was modified (three strategies involving replacement of bleeding on probing with bleeding index >2, counting sites with probing depth ≥6 mm and changing method of bone loss [BL] calculation) to classify patients into different risk groups based on data at the first recall after APT. PRA and three MPRA models were investigated regarding long-term association with tooth loss (TL) and alteration of bone level (∆BL). RESULTS: Based on original PRA, 87 patients (98.8%) had a high-risk profile. According to three MPRA models, annual TL per patient values were greater in high-risk groups than in low-to-moderate risk groups (MPRA-1, 0.20 ± 0.33 versus 0.04 ± 0.14; MPRA-2, 0.18 ± 0.32 versus 0.05 ± 0.14; MPRA-3, 0.17 ± 0.32 versus 0.05 ± 0.15; P <0.05). By MPRA-1, irregular compliers with low-to-moderate risk profile had greater ∆BL (0.027 ± 0.031, indicating bone increment) than those with high risk (-0.012 ± 0.064, tendency for BL). For regular compliers, no significant differences of annual TL or ∆BL were found between risk groups. CONCLUSIONS: MPRA models could be used for evaluating the long-term outcomes of Chinese patients with severe GAgP, especially irregular compliers. High-risk patients of MPRAs exhibited more TL and less bone fill than low-to-moderate risk ones.

The influence of cone-beam computed tomography and periapical radiographic evaluation on the assessment of periapical bone destruction in dog's teeth.

OBJECTIVE: The aim of this study was to determine the influence of periapical radiographs, cone beam computed tomography (CBCT) sections, and cone beam volumetric data on the determination of periapical bone destruction in endodontically treated distal root canals of premolar canine teeth. Nontreated mesial roots were used as controls. STUDY DESIGN: Enterococcus faecalis strain (ATCC 29212) was inoculated into 30 root canals of 2 mongrel dogs to induce apical periodontitis. After 60 days, the root canals of the distal roots of the 11 mandibular and 4 maxillary premolars were endodontically treated (n = 15). The mesial root canals were used as controls (no treatment). The bone destruction was evaluated after 6 months by 5 evaluators using periapical radiographs and by CBCT (coronal and sagittal sections). After the experimental period, the area of the lesions in periapical radiographs and CBCT sections were measured in mm(2) using the ImageTool software. A single evaluator measured the volumetric data using the OsiriX software. The comparison between the diagnosis methods in treated root canals and controls was performed using parametric and nonparametric criteria. The Pearson correlation coefficient was computed between radiographic values and CBCT volumetric data in treated root canals and controls. RESULTS: The results showed the presence of chronic apical periodontitis in every inoculated tooth. After 6 months, periapical radiographs, coronal CBCT sections, and volumetric data showed lower bone destruction in endodontically treated teeth in comparison with the control group (P < .05). The 5 evaluators found no differences between the apical periodontitis area of treated teeth and controls when CBCT sagittal sections were used (P > .05). No correlation was found between x-ray and CBCT volumetric values in treated root canals. CONCLUSIONS: Although selected CBCT sagittal sections showed similar values of bone destruction in endodontically and nontreated root canals, volumetric CBCT data showed that periapical lesions of endodontically treated root canals had half of the volume of periapical lesions in nontreated root canals. No relationship could be found between the periapical values of bone destruction and volumetric data found in CBCT of treated rood canals.

Comparison of the reproducibility of storage phosphor and film bitewings for assessment of alveolar bone loss.

OBJECTIVE: To compare bitewing storage phosphor images and a digital measuring method with bitewing films and an analog measuring method with regard to the reproducibility of measurements of alveolar bone loss. MATERIAL AND METHODS: Nine participants randomly selected from an epidemiological study were radiographically examined using two modalities: bitewing SP images and bitewing films. A digital measuring method was used on the bitewing SP images and an analog measuring method on the bitewing films. Alveolar bone loss was measured at 12 index sites in the premolar/molar region per participant and modality. One hundred measured sites on each modality were assessed twice by three observers. Paired t-test values and intra-class correlation coefficient (ICC) were computed. RESULTS: Comparison of the mean absolute difference of alveolar bone loss between the digital and analog measuring methods demonstrated comparable results (p=0.53). The absolute difference in millimetres between 1st and 2nd measurements was comparable for two observers and statistically different for one. Intra-observer performance between 1st and 2nd measurements was comparable for the digital (ICC=0.85) and analog (ICC=0.83) measuring methods. Inter-observer agreement for the digital measurements was higher (ICC=0.79) than for the analog measurements (ICC=0.64). CONCLUSIONS: The study demonstrates that digital and analog measuring methods are comparable with regard to absolute alveolar bone measurements and intra-observer agreement. Inter-observer comparison demonstrated significantly higher agreement for the digital measurements. Based on the overall results, the modalities with the measuring methods utilized are comparable when measuring minor alveolar bone loss.

Comparison between Scanora panoramic radiography and bitewing radiography in the assessment of marginal bone tissue.

OBJECTIVES: To compare panoramic radiographs made with the Scanora dental program and bitewing radiographs in the assessment of marginal bone tissue. MATERIALS AND METHODS: Panoramic and posterior bitewing radiographs were made for 96 consecutive patients. Six observers assessed marginal bone level, and five observers identified the presence or absence of vertical bone defects and furcation involvements. Observer agreement was calculated. RESULTS: Assessments of the marginal bone level with the two methods were identical for 57% of the sites. If a difference of one score was allowed, assessments for 95% of the sites were in agreement. Vertical bone defects and furcation involvement were detected with an agreement of 93%. Ranges of kappa indexes for intra-observer agreement on assessments of the marginal bone level were 0.37-0.46 in panoramic radiography and 0.31-0.55 in bitewing radiography. Ranges for agreement on detection of vertical bone defects were 0.52-0.63 and 0.47-0.56 and on detection of furcation involvements 0.64-0.79 and 0.66-0.77, respectively. The kappa index for inter-observer agreement on marginal bone level was 0.28 for panoramic and 0.29 for bitewing radiography. Corresponding figures for detection of vertical bone defects were 0.38 and 0.35 and for detection of furcation involvement 0.56 and 0.67. CONCLUSIONS: For those sites or teeth that are possible to assess, the diagnostic information available with Scanora panoramic radiography is comparable to that with bitewing radiography for marginal bone tissue. Therefore, Scanora dental panoramic radiography is a valuable diagnostic alternative in the primary examination of the periodontal status.

The bitewing radiograph as an assessment tool in fixed prosthodontics.

Molar crown preparations, as described in the literature, have standard forms dictated by the demands of retention, resistance and the physical properties of materials. Standard designs may not be appropriate for all patients because of ethnic variations in tooth shape, pulp size and dentine thickness. Accurate data on these features could assist clinicians to minimize the risk of accidental pulpal injury. The aim of this study was to compare the first molar crown and pulp dimensions between Asian (Chinese, Korean, Malay) and other ethnic groups, using measurements from the bitewing radiographs of 121 subjects. Comparisons revealed the following significantly different features of Asian first molars: larger total pulp areas in uppers (P < 0.0005); shorter crowns (P < 0.0005); narrower upper teeth at the cervix (P < 0.0005); wider pulps at the cervix of lowers (P < 0.02); more bulbous crowns (P < 0.0005 for uppers; P < 0.01 for lowers), and finally significantly thinner dentine interproximally at the cervix (P=0.001 for uppers; P=0.011 for lowers). Preparations with wide shoulders could pose hazards to the pulps in Asian subjects. This study emphasizes the value of bitewing films in assessing crown and pulp size and shape before making crown preparations. The experienced practitioner may intuitively include tooth and pulp morphology in treatment planning, but this appears not to be taught or documented in textbooks.

Updated quality assurance self-assessment exercise in intraoral and panoramic radiography. American Academy of Oral and Maxillofacial Radiology, Radiology Practice Committee.

This updated self-assessment exercise for the dental team by the Radiology Practice Committee of the American Academy of Oral and Maxillofacial Radiology is intended to produce the highest quality diagnostic radiographs while keeping patient exposure as low as is reasonably achievable. To continue to provide the best radiographic services to patients, those involved in dental radiography need to be aware of the latest changes and advances in dental radiography and need to use them in their practice.

Effect of X-ray beam vertical angulation on radiographic assessment of alveolar crest level.

Periodontal diseases are diagnosed and monitored by various methods. Probing pocket depth measurements and dental radiographs are two of the most commonly used methods. The aim of this study was to assess the effect of x-ray beam vertical angulation on radiographic assessment of alveolar crest level in five human mandibles. A standardized technique was used to take bitewing radiographs with -10 degrees, 0 degree and +10 degrees angulation of X-Ray beam. The range of the mean differences at individual sites was from 1.84 mm (0.58 +/- SD) to 3.70 mm (1.01 +/- SD). It was found that there was a wide range of over or underestimation of the alveolar crest level due to a change in beam angulation. It was concluded that, to monitor patients with periodontal disease or treatment outcomes, it is important to have reproducible images and bitewing film holders should be used to minimize the X-Ray beam angulation error in general dental practice.

ROC analysis of observer-response subjective rating data--application to periodontal radiograph assessment.

Many physical anthropological studies require that an observer or device discriminate between states that can be easily confused. Receiver operating characteristic (ROC) analysis currently offers the best method for determining the accuracy of such choices, particularly for small sample sizes. Although ROC analysis is widely accepted in psychophysical and biomedical testing, its use in anthropological studies has not been reported. ROC analysis is used here to determine the usefulness of enhanced dental radiographs to assess vertical alveolar bone defects for quantitative studies of human variation with regard to periodontal disease. The presence or absence of vertical-bony defects (truth) for 75 human skulls was established by the consensus of two trained observers. Dental bitewing-radiographs were taken of the alveolar processes, the radiographs digitized, and the brightness and contrast of the digital images enhanced. The two observers who established truth then rated 1) plain bitewing radiographs, 2) unenhanced digital images of bitewings, and 3) enhanced digital images of bitewings for vertical bony defects. The rating scale varied from 1 (vertical defect definitely or almost definitely present) to 5 (definitely or almost definitely absent). ROC analysis was used to compared the diagnostic value of the 3 imaging modalities. All modalities had nearly identical diagnostic performance, measured as Az values (areas beneath ROC curves) that were less than 0.80, which indicates only moderate usefulness. It is concluded that enhancement does not increase success in vertical-bony-defect diagnosis from digital dental radiographs processed in this manner. Moreover, it is suggested that conventional bitewing radiographs may be unsuitable for accurate quantification of such defects.