Optimization of orofacial cleft imaging protocols using device-specific low-dose cone-beam computed tomography.

OBJECTIVE: The aim of this study was to present optimized device-specific low-dose cone-beam computed tomography (CBCT) protocols with sufficient image quality for pre-surgical diagnostics and three-dimensional (3D) modelling of cleft defects. METHODS: Six paediatric skulls were acquired, and an artificial bony cleft was created. A high-resolution CBCT scan acted as a reference standard (Accuitomo 170, Morita, Kyoto, Japan) for comparing eight low-dose protocols of Newtom VGi-evo (QR Verona, Cefla, Verona, Italy), which included Eco and Regular protocols with different field of views (FOVs). Delineation of lamina dura, cementoenamel junction (CEJ), trabecular bone and bony bridge were assessed. A 3D model of the defect was also evaluated. RESULT: The dose area product of low-dose protocols ranged from 31 to 254 mGy*cm2. Despite the dose difference of up to eight times between applied protocols, trabecular bone and CEJ exhibited appropriate image quality in all scans. However, Regular small FOV protocols (5 × 5 and 8 × 5 cm2), for both lamina dura and bony bridge, demonstrated a significant improvement in image quality compared to Eco FOV counterparts. Based on 3D defect analysis, no significant difference existed between low-dose protocols and the reference standard. CONCLUSION: The findings highlight the possibility of achieving a considerable reduction (up to eight times) in the radiation dose using low-dose CBCT protocols while maintaining sufficient image quality for assessing anatomical structures and 3D modelling in cleft cases.

Estimation of the availability of iron in the school meals of Municipal Centers for Early Childhood Education of a capital city in northeastern Brazil.

The final stage of Fe deficiency is Fe deficiency anaemia, with repercussions for human health, especially in children under 5 years of age. Studies conducted in Brazilian public daycare centres show high prevalence of anaemia. The present study aims to evaluate the availability of Fe in the meals of the Municipal Centers of Early Childhood Education in Maceió. The experimental design comprises selection of algorithms, menu evaluation, calculation of the estimates, comparison between the estimates obtained and the recommendations, and analysis of correlation between meal constituents, and of the concordance between the absorbable Fe estimates. Four algorithms were selected and a monthly menu consisting of 22 d. The correlation analysis showed a moderate positive correlation to animal tissue (AT) v. non-heme iron (r = 0·42; P = 0·04), and negative to AT v. Ca (r = -0·54; P = 0·09) and Ca v. phytates (r = -0·46, P = 0·03). Estimates of absorbable Fe ranged from 0·23 to 0·44 mg/d. The amount of Fe available, unlike the total amount of Fe offered, does not meet the nutritional recommendations on most school days. The Bland-Altman analysis indicated that the Monsen and Balinfty and Rickard et al. showed greater agreement. The results confirm the need to adopt strategies to increase the availability of Fe in school meals.

Radiographic perception of anatomical structures and bony changes in oncologic patients under antiresorptive therapy.

PURPOSE: To assess radiographic presentation of anatomical structures, bony changes and soft tissue calcifications on panoramic radiographs of oncologic patients under high dose antiresorptive drug therapy (ART) before exposure to dental extraction. METHODS: Panoramic radiographs of 57 patients under ART, taken previously to tooth extraction, and 57 control patients were evaluated by two oral radiologists regarding bone pattern, anatomical structures visibility, estimation of cortical width, mandibular cortical index (MCI), and presence of soft tissue calcifications. Parameters were compared between ART and age- and gender-matched healthy control groups. Bone patterns were further assessed by regions with or without tooth extractions and according to uneventful healing or MRONJ development. All comparisons were made using chi-square test with significance level set at 5%. RESULTS: Mandible and posterior maxilla presented more sclerotic bone patterns in patients under ART, regardless of tooth extraction and MRONJ development status (p < 0.05). Heterogeneous bone pattern was identified in two regions that both were subsequently affected by MRONJ. Anatomical structure visibility and presence of soft tissue calcifications was not different among groups (p > 0.05). ART patients showed significantly more C0 (thickening) and C1 MCI (p < 0.05). CONCLUSION: Sclerotic bone pattern and thicker mandibular cortices may represent a consequence of ART rather than MRONJ specific findings. Prospective studies on larger patient samples radiographically followed-up during the ART treatment are advised, with specific attention to heterogenous trabecular bone pattern as a possible MRONJ predictor.

Assessment of the root filling volume in C-shaped root canal on cone-beam CT and micro-CT in relation to nano-CT.

AIM: To assess the observed volume of filled C-shaped root canals from different CBCT and micro-CT having nano-CT as a reference. MATERIALS AND METHODS: Twelve extracted mandibular molars with C-shaped root canals were endodontically treated using Reciproc Blue R25 (VDW GMBH, Munich, Germany) in a reciprocating system and filled with gutta-percha (Dentsply Maillefer) and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany). CBCT scans were performed using 3 units-3D Accuitomo 170 (J. Morita, Kyoto, Japan), ProMax 3D Max (Planmeca, Helsinki, Finland), and NewTom VGi EVO (Cefla QR, Verona, Italy)-at two resolution modes: standard and high. Micro-CT and nano-CT scans were also obtained. The volume of all filled C-shaped root canals was obtained using CTAn software (Bruker, Kontich, Belgium), and the blooming artifact, in relation to nano-CT volume, was calculated. The data were evaluated by the Bland-Altman plots and ANOVA two-way for repeated measures (α = 0.05). RESULTS: All CBCT units and micro-CT showed significantly larger observed volume of root canal filling when compared to nano-CT. The blooming artifact of root canal filling in standard resolution was significantly larger than that in high resolution (p < 0.05) in all CBCT units. CONCLUSIONS: Endodontic filling material with AH Plus sealer causes blooming artifacts in CBCT units and micro-CT. CLINICAL RELEVANCE: Considering the anatomical complexity of C-shaped root canals and the challenges associated with endodontic treatment, CBCT is frequently recommended for follow-up evaluations. However, the presence of endodontic filling material can result in blooming artifacts that may potentially impact the accurate diagnosis of endodontic complications.

Surgical guides for guided bone augmentation: An in vitro study.

AIM: To validate in vitro the accuracy of a novel method for bone augmentation of horizontal alveolar bone defects with the help of a surgical guide. MATERIAL AND METHODS: Six cone-beam computed tomography scans of patients requiring horizontal bone augmentation were segmented and 3D printed. Two surgeons performed the bone augmentation surgery twice for each case on 3D-printed models, using either a conventional or guided protocol. Each surgeon virtually planned the desired graft shape beforehand. The resulting grafts were compared linearly and volumetrically to the plan; graft density and surgical time were also analyzed. RESULTS: There was significantly less graft volume outside the planned volume with the guided protocol (36.8% ± 14.1 vs. 19.6% ± 12.3, p < .01). The use of a guide increased graft accuracy at several measurement points, resulting in less overfill when using the guided protocol (1.7 ± 1.7 mm at the most coronal point, 0.2 mm ± 1.4 at 25%, 0.0 mm ± 0.9 at 50%, 0.1 mm ± 1.1 at 75%, and 0.4 mm ± 1.4 apically). Graft thickness was increased 1 mm coronally from the planned graft (2.8 mm ± 2.3 vs. 1.8 mm ± 2.2, p = .04). Surgical time increased significantly when using a guide (a difference of 2 m 26 s). CONCLUSION: The technique, tested here in vitro, allows surgeons to improve the accuracy of the resulting graft shape, to better compact material in the coronal portion of the graft, and to reduce the amount of graft material placed outside the planned volume.

The impact of implant-related characteristics on dental implant blooming: An in vitro study.

AIM: To assess, in vitro, variables potentially influencing implant blooming using a human-like imaging phantom and 3D-printed mandibles. MATERIAL AND METHODS: Sixty implants were inserted in 3D-printed mandibles in 26 different configurations in order to examine the impact of implant diameter, presence of a cover screw, implant design/material, implant position, and the presence of additional implants on implant blooming using two cone-beam computed tomography (CBCT) devices (Accuitomo [ACC] and NewTom [NWT]). Two observers measured the amount of implant blooming in both buccolingual and mesiodistal directions. Inter-rater agreement and descriptive statistics, grouped by implant characteristic and CBCT device, were calculated. RESULTS: Both CBCT devices increased implant diameter (a mean increase of 9.2% and 11.8% for titanium, 20.3% and 24.4% for zirconium, for ACC and NWT, respectively). An increase in implant diameter did not increase the amount of blooming, whereas placing a cover screw did (from 8.0% to 10.9% for ACC, and from 10.0% to 15.6% for NWT). Moreover, implant design, anatomical region, and the presence of another implant also affected the extent of the blooming. CONCLUSIONS: Dental implants show a clear diameter increase on CBCT, with the effect being more pronounced for zirconium than for titanium implants. Similar effects are likely to occur in the clinical setting, potentially masking nonosseointegration, reducing the dimensions of peri-implant defects, and/or causing underestimation of the buccal bone thickness.

Impact of metal artefacts on subjective perception of image quality of 13 CBCT devices.

OBJECTIVES: The overall objective of this study was to assess how metal artefacts impact image quality of 13 CBCT devices. As a secondary objective, the influence of scanning protocols and field of view on CBCT image quality with and without metal artefacts was also assessed. MATERIALS AND METHODS: CBCT images were acquired of a dry human skull phantom considering three clinical simulated conditions: one without metal and two with metallic materials (metallic pin and implant). An industrial micro-CT was used as a reference to register the CBCT images. Afterwards, four observers evaluated 306 representative image slices from 13 devices, ranking them from best to worst. Furthermore, within each device, medium FOV and small FOV standard images were compared. General linear mixed models were used to assess subjective perception of examiners on overall image quality in the absence and presence of metal-related artefacts (p < 0.05). RESULTS: Image quality perception significantly differed amongst CBCT devices (p < 0.05). Some devices performed significantly better, independently of scanning protocol and clinical condition. In the presence of metal artefacts, medium FOV standard scanning protocols scored significantly better, while in the absence of metal, small FOV standard yielded the highest performance. CONCLUSIONS: Subjective image quality differs significantly amongst CBCT devices and scanning protocols. Metal-related artefacts may highly impact image quality, with a significant device-dependent variability and only few scanners being more robust against metal artefacts. Often, metal artefact expression may be somewhat reduced by proper protocol selection. CLINICAL RELEVANCE: Metallic objects may severely impact image quality in several CBCT devices.

Orthodontists' criteria for prescribing cone-beam computed tomography-a multi-country survey.

OBJECTIVES: This study aimed to describe and compare CBCT imaging prescription in clinical practice among orthodontists from five countries in Europe and America. Additionally, it investigated factors associated with the prescribing and the use of guidelines for CBCT imaging. MATERIALS AND METHODS: A cross-sectional survey was carried out using an online questionnaire sent to all registered orthodontists in Belgium, Brazil, Canada, Romania, and the United States of America (USA). The data were analyzed by descriptive statistics, bivariate tests, and Poisson regression. RESULTS: The final sample consisted of 1284 participants. CBCT was prescribed by 84.4% of the participants for selected cases (84.9%), mainly for impacted teeth (92.4%), presurgical planning (54.1%), and root resorption (51.9%). High cost was most frequently the limiting factor for CBCT prescription (55.4%). Only 45.2% of those who were using CBCT imaging reported adhering to guidelines. CBCT imaging prescription was associated with the orthodontists' countries (p < .009, except for Belgium, p = .068), while the use of guidelines was associated with the respondents' country and additional training on CBCT imaging (p < .001). CONCLUSIONS: Orthodontists refer patients for CBCT for selected indications (impacted teeth, root resorption, presurgical planning, dentofacial deformities, as suggested by the international guidelines, and also for upper airway and temporomandibular joint evaluation). Many do not adhere to specific guidelines. There are substantial variations between the countries about the orthodontists' referral for CBCT and guideline usage, irrespective of gender. CBCT prescription may be limited by financial barriers, adhering to specific guidelines and prior CBCT training. CLINICAL RELEVANCE: CBCT prescription among orthodontists must be based on prescription criteria and current guidelines. It is advised to improve CBCT education and training to enhance CBCT selection, referral, analysis, and interpretation in orthodontic practice.

Diagnostic accuracy of CBCT versus intraoral imaging for assessment of peri-implant bone defects.

BACKGROUND: Early detection of marginal bone loss is vital for treatment planning and prognosis of teeth and implant. This study was conducted to assess diagnostic accuracy of CBCT compared to intra-oral (IO) radiography for detection, classification, and measurement of peri-implant bone defects in an animal model. METHODS: Fifty-four mandible blocks with implants were harvested from nine male health adult beagle dogs with acquisition of IO, CBCT and micro-CT images from all samples. Peri-implant bone defects from 16 samples were diagnosed using micro-CT and classified into 3 defect categories: dehiscence (n = 5), infrabony defect (n = 3) and crater-like defect (n = 8). Following training and calibration of the observers, they asked to detect location (mesial, distal, buccal, lingual) and shape of the defect (dehiscence, horizontal defect, vertical defect, carter-like defect) utilizing both IO and CBCT images. Both observers assessed defect depth and width on IO, CBCT and micro-CT images at each side of peri-implant bone defect via CT-analyzer software. Data were analyzed using SPSS software and a p value of < 0.05 was considered as statistically significant. RESULTS: Overall, there was a high diagnostic accuracy for detection of bone defects with CBCT images (sensitivity: 100%/100%), while IO images showed a reduction in accuracy (sensitivity: 69%/63%). Similarly, diagnostic accuracy for defect classification was significantly higher for CBCT, whereas IO images were unable to correctly identify vestibular dehiscence, with incorrect assessment of half of the infrabony defects. For accuracy of measuring defect depth and width, a higher correlation was observed between CBCT and gold standard micro-CT (r = 0.91, 95% CI 0.86-0.94), whereas a lower correlation was seen for IO images (r = 0.82, 95% CI 0.67-0.91). CONCLUSIONS: The diagnostic accuracy and reliability of CBCT was found to be superior to IO imaging for the detection, classification, and measurement of peri-implant bone defects. The application of CBCT adds substantial information related to the peri-implant bone defect diagnosis and decision-making which cannot be achieved with conventional IO imaging.

Osteomyelitis, osteoradionecrosis, or medication-related osteonecrosis of the jaws? Can CBCT enhance radiographic diagnosis?

OBJECTIVE: To attempt defining differential radiographic diagnostic characteristics for osteonecrotic lesions using 2D as opposed to 3D images. MATERIALS AND METHODS: This was a cross-sectional study. Subjects presenting mandibular osteonecrotic lesions (osteomyelitis, osteoradionecrosis, and medication-related osteonecrosis of the jaws) were selected and compared to a group of age- and gender-matched controls, all having both cone-beam computed tomographic images (CBCT) and panoramic radiographs (PANO). Both imaging modalities (predictor variables) were evaluated by two radiologists that scored lesion presence, eight additional radiological features, and a composite severity index (outcome variables). For each pathologic condition, characteristic features were assessed in PANO and CBCT by the Wilcoxon signed-rank test. Regression tree analysis revealed the predictive value of PANO and CBCT (α = 5%). RESULTS: Overall, the predictive value of PANO reached 74%, while for CBCT it became 90%. Regarding the composite severity index, CBCT enabled to detect more subtle lesions. Also, CBCT imaging allowed showing more distinct radiographic diagnostic features as compared to PANO imaging, more specifically when distinguishing osteomyelitis from both other lesions. CONCLUSIONS: Cone-beam computed tomography enabled showing more differences in radiological features between distinct osteonecrosis disease entities. CBCT imaging might be a better contributor for the detection of early lesions and to monitor further pathological developments in the mandible.

Dentomaxillofacial CBCT: Clinical Challenges for Indication-oriented Imaging.

This critical review discusses the clinical challenges for patient-specific and indication-oriented dentomaxillofacial cone beam computed tomography (CBCT). Large variations among units and protocols may lead to variable degrees of diagnostic and three-dimensional model accuracy, impacting both specific diagnostic tasks and treatment planning. Particular indications, whether diagnostic or therapeutic, may give rise to very specific challenges with regard to CBCT unit and parameter setup, considering the required image quality, segmentation accuracy, and artifact level. Considering that dental materials are in the field of view needed for diagnosis or treatment planning, artifact expression is a dominant factor in proper CBCT selection. The heterogeneity of dental CBCT units and performances may highly impact the scientific results. Thus research findings cannot be simply generalized as published evidence, and a demonstrated clinical applicability for a specific indication should not be simply extrapolated from one CBCT unit to another.

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.

Inaccuracy of buccal bone thickness estimation on cone-beam CT due to implant blooming: An ex-vivo study.

AIM: The aim of this article was to evaluate the accuracy of buccal bone thickness measurements around implants on CBCT. MATERIAL AND METHODS: Forty-four Osseospeed EV implants (3.6 in Ø) were placed guided and flapless in five fresh frozen human cadaver heads. The buccal peri-implant bone was measured clinically via guided bone sounding. Post-op CBCTs were taken with two different CBCT scanners (NewTom® and Accuitomo® ) on which the buccal bone was measured. Consequently, after implant removal, a new CBCT was made without implant artefacts (image reference standard) on which the real buccal bone thickness was scored. RESULTS: Due to an average blooming (artificial increase of implant diameter) percentage of 12%-15%, the buccal peri-implant bone thickness was underestimated by 0.3 mm on both CBCT devices. Immediately adjacent to the implant blooming area, a doubtful zone of about 0.45 mm was observed in which the buccal bone was not always visible. Buccal bone that was thick enough to fall outside this doubtful zone could always be visualized. CONCLUSION: The findings in this study may help the clinician in the decision-making process whether or not to intervene surgically in areas with ambiguous CBCT results.

Comparative evaluation of cone beam CT and micro-CT on blooming artifacts in human teeth filled with bioceramic sealers.

AIM: To assess blooming artifacts caused by root canal sealers in CBCT images compared with those that appeared in micro-CT scan images used as references. MATERIALS AND METHOD: Thirty freshly extracted human mandibular central incisors were used. Root canals were prepared with nickel titanium files with an ISO size 40/0.06 taper and filled with a single cone (40/0.06 taper) and three different sealers. The samples were divided into the following three groups with 10 roots each: (I) AH Plus sealer; (II) Sure Seal Root; and (III) Total BC sealer. Teeth were scanned with the same voxel sizes (0.2 mm) in different CBCT devices and the micro-CT images were acquired as reference images. RESULTS: Significantly different results in terms of blooming artifacts were detected between CBCT and micro-CT images, as well as among the CBCTs images. The canals filled with AH Plus sealer showed more blooming artifacts than those filled with bioceramic sealers (p < 0.05). Additionally, the worst blooming artifact was observed when the images were acquired with lower kilovoltage peak. CONCLUSION: The appearance of blooming artifacts is dependent on sealer and CBCT, and their effects are significantly worse than they are in micro-CT images. The differential effect of different sealers and distinct CBCT protocols should be further investigated to enable the use of bioceramic sealers without a significant impact on post-treatment imaging. CLINICAL RELEVANCE: Root canal sealers showed a different extent of blooming artifact in CBCT images. Hence, researchers and clinicians should be aware of these artifacts before conducting endodontic evaluations using CBCT images.

Quantitative evaluation of metal artifacts using different CBCT devices, high-density materials and field of views.

OBJECTIVE: To objectively compare the influence of different cone-beam computed tomography (CBCT) devices, high-density materials and field of views (FOVs) on metal artifact expression. MATERIAL AND METHODS: For this in vitro study, three customized acrylic resin phantoms containing high-density materials cylinders: titanium, copper-aluminum alloy and amalgam were scanned on three CBCT devices using high-resolution protocols, same voxel size (0.2 mm) and different FOVs. After fully automatic segmentation and image registration, the same region of interest was defined for the small and medium FOVs. The difference between the segmented and the real volume of the metal cylinders was assessed. Moreover for each segmented slice, the area difference between the segmented and the real axial section was determined. The artifacts on the background were measured as normalizing standard deviation of voxel values in the vicinity of the cylinder, in three different distances. RESULTS: Considerable differences were observed in volume measurements for all CBCTs devices and materials for both FOV sizes (up to 67%). The slice per slice area analysis indicated higher artifacts at the edges of the metal cylinder. Within the materials, amalgam and titanium had, respectively, the worst and best artifact expression in all the CBCT devices. Standard deviation values varied differently between the three distances in each device. CONCLUSION: Our in vitro study showed that different CBCT devices, high-density materials and FOV should be considered while evaluating CBCT images. More carefully, diagnosis conclusions should be drawn in images containing amalgam and copper-aluminum alloy.

MicroCT assessment of bone microarchitecture in implant sites reconstructed with autogenous and xenogenous grafts: a pilot study.

PURPOSE: To assess bone microarchitecture in maxillary sites grafted with autogenous or xenogenous grafts as well as to demonstrate the usefulness of microCT in dental implant research. MATERIALS AND METHODS: Samples (n = 12) consisting of titanium fixation screws covered by at least 0.5-1 mm of human bone were obtained from 17 sites grafted with autogenous or xenogenous materials and prepared for microCT scanning and conventional histology. Bone histomorphometric parameters were evaluated in three distinct regions (graft region, transitional region, and native bone region). Three-dimensional (3D) bone-to-implant contact (BIC) calculation was performed using microCT data. Histological sections were used to calculate two-dimensional (2D) BIC percentages, which were compared with values obtained from 2D microCT images. RESULTS: Histomorphometric parameters varied according to the type of graft used, but sites reconstructed with autogenous bone showed higher mean values in general. In autograft samples, indices for parameters such as Tb.Th and Tb.Sp were significantly different when the native bone region was compared to the graft region. While a higher mean 3D BIC was found in the native bone region for both graft materials, significant BIC differences were absent when graft types were compared. The 2D BIC percentages obtained from histological and microCT images were similar. CONCLUSIONS: Autografts outperformed the xenogenous material used in this study concerning the histomorphometric parameters assessed. While graft type did not seem to influence 3D BIC, the native bone region showed the highest BIC percentages when compared to the other regions in both graft groups. In addition, 2D BIC ratios were similar regardless of graft material or image source (histological sections x microCT slices). Taken together, our findings suggest that microCT is an effective tool for 2D and 3D histomorphometric and BIC assessments in dental implant research.

Diagnostic accuracy of phosphor plate systems and conventional radiography in the detection of simulated internal root resorption.

OBJECTIVE: To evaluate the performance of conventional radiography and photostimulable phosphor (PSP) plate in the detection of simulated internal root resorption (IRR) lesions in early stages. MATERIALS AND METHODS: Twenty single-rooted teeth were X-rayed before and after having a simulated IRR early lesion. Three imaging systems were used: Kodak InSight dental film and two PSPs digital systems, Digora Optime and VistaScan. The digital images were displayed on a 20.1″ LCD monitor using the native software of each system, and the conventional radiographs were evaluated on a masked light box. Two radiologists were asked to indicate the presence or absence of IRR and, after two weeks, all images were re-evaluated. Cohen's kappa coefficient was calculated to assess intra- and interobserver agreement. The three imaging systems were compared using the Kruskal-Wallis test. RESULTS: For interexaminer agreement, overall kappa values were 0.70, 0.65 and 0.70 for conventional film, Digora Optima and VistaScan, respectively. Both the conventional and digital radiography presented low sensitivity, specificity, accuracy, positive and negative predictive values with no significant difference between imaging systems (p = .0725). CONCLUSIONS: The performance of conventional and PSP was similar in the detection of simulated IRR lesions in early stages with low accuracy.

Impact of cone-beam computed tomography scan mode on the diagnostic yield of chemically simulated external root resorption.

INTRODUCTION: The aim of this in-vitro study was to evaluate the influence of cone-beam computed tomography scans on the diagnosis of chemically simulated external root resorption. METHODS: One hundred extracted anterior teeth were selected. Subsurface demineralization was induced on a limited area of the apical third of the root of 49 teeth. Each tooth was placed in an empty socket of a partially edentulous dry mandible. Cone-beam computed tomography images were obtained according to 3 protocols: (1) half scan, 0.40-mm voxel size; (2) full scan, 0.40-mm voxel size; and (3) full scan, 0.125-mm voxel size. Three observers evaluated the images. Sensitivity, specificity, accuracy, and area under the curve were compared with the Cochran Q and Mann-Whitney U tests. RESULTS: Protocol 3 had the highest sensitivity (81.63%), accuracy (80.67%), and area under the curve (0.807). There were statistically significant differences between protocol 3 and the other 2 protocols (P <0.001). The specificity of protocol 1 (84.97%) was greater than that of protocols 2 (69.93%) and 3 (79.74%); however, a statistically significant difference was found only between protocols 1 and 2 (P = 0.005). CONCLUSIONS: A more dedicated, high-resolution scan should be acquired when one intends to investigate the early stage of external root resorption during orthodontic treatment. However, this does not imply that all orthodontic patients should be subjected to high-dose cone-beam computed tomography scans.

Chenopodium Ambrosioides Linn Mitigates Bone Loss in Rats with Periodontitis.

Statement of the Problem: Periodontitis is an inflammatory disease that causes bone loss. Some patients do not respond well to the classic treatment and need therapies that minimize bone loss, the main sequel of the disease. Chenopodium ambrosioides L. has stood out due to its anti-inflammatory and anti-oxidative activities. However, no study has yet investigated its effect on periodontitis. Purpose: This study aimed to evaluate the bone protective effect of Chenopodium ambrosioides L. (CAL) extract on ligature-induced periodontitis model in rats. Materials and Method: For this, a pre-clinical assay was performed, using male Wistar rats divided into 3 groups: Naive (N) (n=6), not submitted to any procedure; Saline (SAL) (n=6), submitted to ligature-induced periodontitis and receiving 2 ml/kg of 0.9% saline solution; and CAL extract, which was subdivided into 3 subgroups (n=6/subgroup) receiving the CAL at 3 (CAL3), 10 (CAL10) or 30 mg/kg (CAL30). All agents were given, by oral gavage, 30 min before periodontitis induction and daily until euthanasia (11th day). By then, maxillae were removed for macroscopic, histological, and histometric analyses. Kidneys, liver, and stomach were collected to evaluate the safety of CAL extract. High-performance liquid chromatography (HPLC) assay was used to investigate the flavonoid content in the extract. Results: Chenopodium ambrosioides L. extract at 30mg/kg showed a reduction by 58% in bone loss marked by an increase (+35%) in the number of osteoblasts and a reduction (-51%) on the number of osteoclasts (p< 0.05). No significant alteration in the liver, kidney, or stomach was seen. Rutin was the main flavonoid found. Conclusion: In summary, it was observed that Chenopodium ambrosioides L. extract has shown important anti-inflammatory and bone anabolic and anti-resorptive properties without causing toxicity in the main organs. Rutin, as the main flavonoid of the extract, seems to be responsible for the beneficial effect of this agent.

The impact of CBCT-head tilting on 3D condylar segmentation reproducibility.

OBJECTIVES: To investigate whether variations in head positioning may influence the reproducibility of cone-beam CT (CBCT) three-dimensional (3D) segmented models of the mandibular condyle. METHODS: Five fresh frozen cadaver heads were scanned in four different positions: reference position (RP) and a set of three tilted alternative head positions (AP) in anteroposterior direction (AP1: 2 cm anterior translation, AP2: 5° pitch rotation, AP3: 10° pitch rotation). Surface models of mandibular condyles were constructed and compared with the condylar reference position using voxel-based registration. Descriptive statistics and a linear mixed-effects model were performed to compare condylar volumetric differences and root mean square (RMS) distance between surfaces of AP vs RP. RESULTS: The mean differences in condylar volumes of AP vs RP were 14.1 mm³ (95% CI [-79.3, 107.4]) for AP1, 1.0 mm³ (95% CI [-87.2, 89.2]) for AP2 and 0.1 mm³ (95% CI [-88.3, 88.4]) for AP3. Mean and absolute volumetric differences did not exceed earlier reported intraoperator differences of 30 mm³. The RMS distance values obtained per group were 0.12 mm (95% CI [0.05,0.20]) for AP1, 0.17 mm (95% CI [0.10, 0.22]) for AP2 and 0.17 mm for AP3 (95% CI [0.10,0.22]). The confidence intervals (CI) for RMS distance remained far below the threshold for clinical acceptability (0.5 mm). CONCLUSIONS: Within the limits of the present study, it is suggested that tilted head positions may affect the reproducibility of 3D condylar segmentation, thereby influencing outcome in repeated CBCT scanning. Nevertheless, observed differences are unlikely to have a meaningful impact on clinical patient diagnosis and management.