Frequency of Accessory Maxillary Ostium in Patients With/Without Sinusitis, and Its Correlation with Anatomical Variations of Paranasal Sinuses: A Cone Beam Computed Tomography Study.

This study assessed the frequency of accessory maxillary ostium (AMO) in patients with/without sinusitis and its correlation with anatomical variations using cone-beam computed tomography (CBCT). In this cross-sectional study, 244 CBCT scans were evaluated in two groups: with maxillary sinusitis having > 2 mm mucosal thickening and without max sinusitis as a normal group having normal or less than 2 mm mucosa. The CBCT scans of each group were carefully evaluated for the presence/absence of AMO, patency/obstruction of the primary maxillary ostium (PMO), and the presence of anatomical variations of the paranasal sinuses. Data were analyzed by independent t-test, Pearson Chi-square test, and Fisher's exact test (alpha = 0.05). CBCT scans of 134 females (54.9%) and 110 males (45.1%) with a mean age of 34.16 ± 19.01 years were evaluated. The presence of AMO had no significant correlation with maxillary sinusitis (P = 0.104). The two groups had no significant difference in the frequency of Haller cell, nasal septal deviation, and concha bullosa (P > 0.05). However, the frequency of paradoxical concha (PC; P < 0.001) and bifid concha (BC; P = 0.017) was significantly higher in the normal group, and the frequency of PMO obstruction was significantly higher in the sinusitis group (P < 0.001). AMO had no significant correlation with any anatomical variation in any group (P > 0.05). Gender had a significant effect on the presence of AMO (P = 0.013). The presence of AMO had no significant correlation with maxillary sinusitis. However, its frequency was significantly higher in females in normal group and males with sinusitis. The presence of AMO had no significant correlation with anatomical variations.

Introducing a new auto edge detection technique capable of revealing cervical root resorption in CBCT scans with pronounced metallic artifacts.

Cervical resorption is a serious threat to the longevity of the teeth. In this study, the Canny edge-detection algorithm was applied on CBCT images to compare the accuracy of original and Canny views for diagnosing cervical resorption in endodontically treated teeth. Intracanal metallic posts were inserted in 60 extracted teeth being randomly divided into three groups: control, 0.5 mm, and 1 mm cervical resorption. CBCT scans of the teeth were presented to three observers in both original and Canny formats with the accuracy being determined by receiver operating characteristic (ROC) analysis. The DeLong test was used for paired comparisons with the significance level set at 0.05. The highest accuracy belonged to Canny images in 1 mm resorption, followed by Canny images in 0.5 mm resorption, original images in 1 mm resorption, and original images in 0.5 mm resorption, respectively. The Canny images were significantly more accurate in the diagnosis of 0.5 mm (p < 0.001) and 1 mm (p = 0.009) resorption. Application of the Canny edge-detection algorithm could be suggested as a new technique for facilitating the diagnosis of cervical resorption in teeth that are negatively affected by metallic artifacts.

Relationship of the Fusion Stage of Spheno-Occipital Synchondrosis with Midpalatal and Zygomaticomaxillary Sutures on Cone-Beam Computed Tomography Scans of Patients Aged Between 7 and 21 Years.

Objective: This study assessed the relationship of the fusion stage of spheno-occipital synchondrosis (SOS) with midpalatal (MPS) and zygomaticomaxillary (ZMS) sutures on cone-beam computed tomography (CBCT) scans of 7 to 21-year-old patients. Methods: This cross-sectional study evaluated the CBCT scans of 176 patients between 7 and 21 years presenting to a maxillofacial radiology clinic. The fusion stage of SOS was determined using a five-stage classification system. The percentage of opening depth of MPS was measured on two middle coronal cuts in the anterior and posterior half of the palate. To assess ZMS, suture fusion was evaluated in four age groups in the axial cut visualizing its maximum length. Data were analyzed using the Kruskal-Wallis, Mann- Whitney U, and Bonferroni tests and regression models. Results: The percentage of MPS opening significantly decreased in both the anterior and posterior halves with age (p<0.002). With an increase in SOS grade, the percentage of MPS opening in both the anterior and posterior halves significantly decreased (p<0.001). By an increase in the ZMS stage, the SOS grade significantly increased (r=0.565, p<0.001). Conclusion: The MPS opening percentage in the anterior and posterior halves decreased with age, with a greater reduction in the posterior half. A significant inverse correlation exists between the SOS fusion stage and the percentage of MPS opening. In SOS grades I-III, the mean percentage of MPS opening was 100% in all age groups (with the highest frequency of ZMS stage I), indicating a higher chance of success for orthodontic treatments such as rapid maxillary expansion in these individuals.

Diagnostic accuracy of cone-beam computed tomography with modified grayscale range for detection of buccal cortical plate defects adjacent to dental implants.

Background: This study assessed the diagnostic accuracy of cone-beam computed tomography (CBCT) with a modified grayscale range for the detection of buccal cortical plate defects adjacent to dental implants. Materials and Methods: In this in vitro experimental study, titanium implants were inserted in 168 fresh bovine bone blocks with 1-1.5 mm of buccal cortical plate thickness. The blocks were randomly divided into four groups (n = 42). No defect was created in the control blocks. In the three experimental groups, cortical plate defects were randomly created in the cervical, middle, or apical third by a round bur with a 2-mm diameter (n = 42). All blocks underwent CBCT with and without change in the grayscale range. Two observers evaluated all images regarding the presence/absence of defects. Kappa test is used for the agreement of the observers. The diagnostic accuracy of the two modalities was compared by calculating the area under the receiver operating characteristic curve (AUC) (P ≤ 0.05). The sensitivity and specificity values were also compared. Results: The AUC was not significantly different between the two modalities with and without altered grayscale range (0.754 vs. 0.762, respectively, P = 0.716). The diagnostic sensitivity of CBCT with and without change in the grayscale range was 51% and 52%, respectively, with a specificity of 100% for both. The diagnostic accuracy of CBCT with and without altered grayscale range had no significant difference for apical and middle third defects (P > 0.05) and was significantly higher than that for the cervical third defects (P < 0.05). Conclusion: Changing the grayscale range does not improve the diagnostic accuracy of CBCT for the detection of buccal cortical plate defects adjacent to dental implants.

Computed Tomographic Comparison of Length, Width and Angulation of Ethmoidal Infundibulum in Patients With and Without Maxillary Sinusitis.

Ethmoidal infundibulum (EI) is an important part of the osteomeatal complex, which provides the main pathway for the maxillary sinus drainage. This study aimed to compare the length, width, and angulation of EI in patients with/without maxillary sinusitis using computed tomography (CT). This cross-sectional study evaluated 818 spiral CT scans of patients with/without maxillary sinusitis (n = 409 maxillary sinuses in each group) classified according to the clinical symptoms and the Lund-Mackay score for mucosal thickening. The degree of mucosal thickening (on axial and coronal sections), anatomical variations namely concha bullosa (CB), ethmoidal bulla (EB), and Haller cells (HCs), the form of EI (on coronal sections), the length, width and angulation of EI, and degree of nasal septal deviation (on coronal sections) were all evaluated. Data were analyzed by parametric and non-parametric tests (alpha = 0.05). The frequency of EB (P < 0.001), EI form (P < 0.001) and HC (P = 0.011), and the length and width of EI (P < 0.001) were significantly different in patients with and without maxillary sinusitis. The length and width of EI were significantly correlated with the degree of mucosal thickening (P < 0.01). The frequency of CB (P = 0.002), EB (P < 0.001), and HC (P = 0.002), and the EI form (P < 0.001) were significantly different in groups with different degrees of mucosal thickening. EI was wider and shorter in patients with maxillary sinusitis. By an increase in mucosal thickness, the length of EI decreased while its width increased. Also, the frequency of EB and HC, and the EI form were significantly different in the two groups.

The Relationship Between Temporal Bone Pneumatization Pattern and Sinus Mucosal Thickness Grading on Computed Tomography Scans of Paranasal Sinuses.

The relationship between temporal bone pneumatization (TBP) pattern and sinus mucous thickness grading on computed tomography scans of paranasal sinuses was investigated. In this cross-sectional study, a total of 200 temporal bones and paranasal sinuses were evaluated in CT scans of 100 patients with chronic sinusitis (CRS). The mucosal thickness of paranasal sinuses was classified into two groups (0-6 and 7-12) according to the Lund-Mackay (LM) staging system. Also, pneumatization patterns of petrous apex and perilabyrinthine regions were classified according to Jadvah et al. method. Data were analyzed using Chi-square and Fisher's exact tests. The most common pneumatization pattern in the petrous apex was pattern A (49.5%) and in the perilabyrinthine region was pattern B (50%). In the petrous apex, the highest frequencies of pattern A (51.7%) and pattern C (24.6%), among other pneumatization patterns, were found in score range of 7-12 and 0-6, respectively, which was statistically significant (P = 0.017). Although in the perilabyrinthine region, the highest frequencies of pattern A (24.1%) and pattern C (32.7%) were in LM score ranges of 7-12 and 0-6, respectively, no significant difference was found (P = 0.589). The petrous apex pneumatization decreases with an increase in the severity of CRS, which can be in response to the eustachian tube dysfunction and common pathogens with CRS. A similar relationship was also found in the perilabyrinthine region, although it was not statistically significant. No significant relationship between TBP and severity of CRS was found in the age and sex groups.

A diagnostic accuracy study on an innovative auto-edge detection technique for identifying simulated implant fractures on radiographic images.

Implant fracture is a rare but devastating complication of treatment in partially or fully edentulous patients which requires prompt diagnosis. Nevertheless, studies on defining the most accurate technique for the detection of implant fractures are lacking. In the present study, the Canny edge detection algorithm was applied on multiple radiographic modalities including parallel periapical (PPA), oblique periapical (OPA), and cone beam CT (CBCT) with and without metal artifact reduction (MAR) to examine its accuracy for diagnosis of simulated implant fractures. Radiographs were taken from 24 intact implants and 24 implants with artificially created fractures. Images were evaluated in their original and Canny formats. The accuracy of each radiograph was assessed by comparison with a reference standard of direct observation of the implant. The greatest area under the receiver operating characteristic curve belonged to Canny CBCT with MAR (0.958), followed by original CBCT with MAR (0.917), original CBCT without MAR = Canny CBCT without MAR = Canny OPA (0.875), Canny PPA (0.833), original PPA = original OPA (0.792), respectively. The Canny edge detection algorithm is suggested as an innovative method for accurate diagnosis of clinically suspected implant fractures on CBCT and periapical radiographies.

Post-COVID mucormycosis osteomyelitis and its imaging manifestations in the North of Iran: case series.

Mucormycosis is an invasive fungal infection that usually affects patients with immunocompromised conditions. In the context of the COVID-19 pandemic and the following corticosteroid therapy, mucormycosis prevalence has increased. The situation may be more complicated with some underlying diseases such as diabetes mellitus. In addition, due to the vicinity of maxillary bone to the nasal cavity and paranasal sinuses, which are the main routes for the infection to spread, dentists, maxillofacial radiologists, and surgeons may be the first to encounter these patients. Post-COVID mucormycosis osteomyelitis is one of the complications of this infection Bone destruction and the erosion or breach of cortical boundaries of the maxilla and the bone structures in the vicinity of paranasal sinuses are the most critical radiographic findings of post-covid osteomyelitis. Herein, there are some cases of post-covid mucormycosis osteomyelitis involving the maxillary and other facial bones.

Evaluation of Palatal Bone Thickness and Its Relationship with Palatal Vault Depth for Mini-Implant Insertion Using Cone Beam Computed Tomography Images.

OBJECTIVE: The purpose of this study was to measure the thickness of the palatal bone using cone beam computed tomography images for placement of mini-screws and their relationship with palatal vault depth. METHODS: This study was performed on 150 maxillary cone beam computed tomography images, 50% (n = 75) had deep palate and 50% (n = 75) had normal palate and 27.3% (n = 41) were male and 72.7% (n =109) were female. Coronal sections with a thickness of 1 mm were prepared at distances of 4 mm, 8 mm, 12 mm, 16 mm, 20 mm, and 24 mm from the posterior wall of the incisive foramen. Then, in each section, in the midsagittal line and at distances of 2 mm, 4 mm, 6 mm, 8 mm, and 10 mm from that to the lateral sides, the bone thickness was measured. The Korkhaus index was used to identify the patients with a high palatal vault. RESULTS: The results showed that at the posterior sections in the midsagittal and parasagittal area, a significant difference (P < .05) was observed between deep and normal palate, and in these points, the bone thickness in the normal palate was greater. Also, in the section of 4 mm and 8 mm, a significant difference was observed between males and females in most of these points, and those were greater in males than females. CONCLUSION: The maximum thickness of the palatal bone was observed first along the midsagittal line and then the paramedian and in the anterior section. Patients with deep palate had less palatal bone thickness in the posterior sections.

Efficacy of cone-beam computed tomography with modified gray-scale range versus digital periapical radiography for the assessment of bone-implant interface gaps.

OBJECTIVES: To compare the efficacy of digital periapical (PA) radiography with cone-beam computed tomography (CBCT) by altering the gray-scale range for the detection of bone-implant interface gaps. METHODS: Titanium implants were placed in 52 blocks of bovine rib such that 42 had no gaps and served as the control group. The implants were subsequently placed in the same blocks with 0.25 mm increase in the osteotomy size to serve as the test group. The remaining 10 blocks were used for random arrangement of the test and control blocks within a fabricated wax arch. CBCT with change in the gray-scale range and digital PA were obtained and evaluated by two observers regarding the presence/absence of gaps. The two imaging modalities were compared by the receiver operating characteristic (ROC) curve, Kappa and McNemar tests (α = 0.05). RESULTS: PA and CBCT showed moderate agreement for gap detection (k = 0.60). There were no significant differences in the area under the ROC curve (AUC) between CBCT and PA (P = 0.45). The frequency of correct diagnoses on PA radiographs was significantly higher in the test group (P = 0.016), while not significant on the CBCT images (P = 0.344). PA showed higher sensitivity (100%) compared to CBCT (83.33%). However, the specificity of CBCT (92.86%) was greater than that of PA (83.33%). CONCLUSIONS: Certain gray-scale ranges in CBCT enhance the assessment of bone-implant interface which brings the accuracy of CBCT closer to digital PA radiography as the modality of choice.

Application of an auto-edge counting method for quantification of metal artifacts in CBCT images: a multivariate analysis of object position, field of view size, tube voltage, and metal artifact reduction algorithm.

OBJECTIVE: The objective was to assess the effects of object position, field of view (FOV) size, peak kilovoltage (kVp), and a metal artifact reduction (MAR) algorithm on metal artifacts in cone beam computed tomography (CBCT) as measured with an auto-edge counting method. STUDY DESIGN: A titanium implant and a stainless steel intracanal post in a root were inserted in bovine rib blocks. CBCT scans were acquired with changes in object position (incisor, canine, and premolar-molar areas), FOV, kVp, and MAR (on or off) mode. Images were quantitatively analyzed in MATLAB by using the Canny edge detection algorithm. Four-way analysis of variance and Tukey tests were applied for data analysis. RESULTS: The implant produced no significant differences in number of artifacts among the object positions through changing the kVp and MAR mode for all FOV sizes (P > .05). The intracanal post scanned with the medium-sized FOV, high kVp, and MAR off mode generated significant differences among object positions (P = .033). Among the variables assessed, FOV size and MAR mode had a significant influence on the number of artifacts (P ≤ .039). CONCLUSION: Reduction of FOV size and application of the MAR tool significantly decreased the number of streak artifacts. The Canny edge detection algorithm could be an efficient method of metal artifact quantification.

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.

Accuracy of digital bitewing radiographs with and without applying horizontal tube shift in the diagnosis of residual excess cement around dental implants: an in vitro study / Precisión de las radiografías digitales bitewing con y sin aplicación de desplazamiento horizontal del tubo en el diagnóstico del exceso de cemento residual alrededor de los implantes dentales: un estudio in vitro

Purpose: This study was designed to evaluate the diagnostic value of digital Bitewing (BW) radiographs with and without horizontal tube shift in detecting Residual excess cement (REC) on the proximal and non-proximal surfaces of implant restorations. Material and Methods: Eight mandibular models were fabricated with two implants placed on each side in the premolar and first molar positions. Excess cement was applied to either proximal or non-proximal surfaces of the restorations intentionally during the process of crown cementation. BW radiographs with and without applying horizontal tube shift were acquired. Three maxillofacial radiologists were asked to determine the presence and location of REC in the radiographs. Sensitivity and specificity of the radiographic technique were assessed according to the restoration surface that contained REC. Results: Sensitivity of BW radiographs was 100% for the detection of REC on the proximal surfaces and 41-18, 80% on the non-proximal surfaces. Specificity of the technique was 85.71%-100% for the proximal surfaces and 75-94. 12% for the non-proximal areas. Specificity of the radiographic method was generally greater than its sensitivity for the non-proximal surfaces while in the proximal areas, the two variables had quite similar values. Conclusion: Digital BW radiography is generally more useful for detection of REC on the proximal surfaces. Higher specificity of this technique for the bucco-lingual surfaces suggests more reliability of the negative diagnoses in the non-proximal areas.

Objetivo: Evaluar el valor diagnóstico de las radiografías digitales bitewing (BW), con y sin desplazamiento horizontal del tubo, para detectar el exceso de cemento residual (ECR) en las superficies proximales y no proximales de las restauraciones con implantes. Material y Métodos: Se fabricaron ocho modelos mandibulares con dos implantes colocados a cada lado en las posiciones premolar y primer molar. El exceso de cemento se aplicó intencionalmente en las superficies proximales o no proximales de las restauraciones durante el proceso de cementación de la corona. Se adquirieron radiografías BW con y sin aplicación de desplazamiento horizontal del tubo. Se pidió a tres radiólogos maxilofaciales que determinaran la presencia y ubicación de ECR en las radiografías. La sensibilidad y la especificidad de la técnica radiográfica se evaluaron según la superficie de restauración que contenía ECR. Resultados: La sensibilidad de las radiografías de BW fue del 100% para la detección de ECR en las superficies proximales y del 41,18-80% en las superficies no proximales. La especificidad de la técnica fue 85-71, 100% para las superficies proximales y 75-94, 12% para las áreas no proximales. La especificidad del método radiográfico fue generalmente mayor que su sensibilidad para las superficies no proximales, mientras que en las áreas proximales, las dos variables tuvieron valores bastante similares. Conclusión: La radiografía digital BW es generalmente más útil para la detección de ECR en las superficies proximales. La mayor especificidad de esta técnica para las superficies buco-linguales sugiere una mayor confiabilidad de los diagnósticos negativos en las áreas no proximales.

Comparison of Success Rates of Cone Beam Computed Tomography in the Retrieval of Metal-Ceramic vs All-Ceramic Implant-Supported Restorations: An In Vitro Study.

PURPOSE: To assess the success rates of cone beam computed tomography (CBCT) in identifying the locations and directions of abutment screw access holes (ASAHs) in metal-ceramic and all-ceramic implant restorations. MATERIALS AND METHODS: Thirty-two implants were inserted into four clear acrylic casts. Metal-ceramic and all-ceramic crowns were placed on the inserted implants in two successive tasks. A maxillofacial radiologist determined the locations and angles of the ASAHs based on the CBCT images that were taken from the casts. Locations obtained from the CBCT images were carefully transferred to the crowns as access points. A prosthodontist pierced the crowns along the proposed access points and in the direction determined based on the CBCT images. Proper crown removal was considered to be the mark of success of CBCT in detecting ASAH location and direction. Fisher exact and chi-square tests were used to compare the results between the two types of restoration. RESULTS: Success rates of CBCT for defining ASAH location and direction were, respectively, 96.9% and 93.8% in metal-ceramic restorations and 78.1% and 59.4% in all-ceramic restorations. There were no significant differences between the two restoration types regarding the detection of location in either molar (P = .333) or premolar (P = .226) crowns. Abutment angle did not affect the success rate of CBCT in determining ASAH location or direction in metal-ceramic restorations. CONCLUSION: CBCT images define the locations and directions of ASAHs in metal-ceramic restorations more reliably than in all-ceramic restorations. In contrast to the metal-ceramic crowns, the success rate of CBCT in all-ceramic crowns is more dependent on abutment angle and crown morphology.

Cone-Beam Computed Tomographic Assessment of Bone Thickness in the Mandibular Anterior Region for Application of Orthodontic Mini-Screws.

OBJECTIVE: To determine the proper zones for placement of orthodontic mini-screws, based on cone-beam computed tomography (CBCT) measurements in the anterior mandibular region. METHODS: The current cross-sectional study was performed on CBCT images of 77 individuals in the age range of 18-60 years. Axial slices at the levels of 2, 5, and 8 mm from the cementoenamel junction (CEJ) of the mandibular anterior teeth were selected. Interdental distances were measured in the mesiodistal direction, parallel to the midline of the mandibular arch. Areas with more suitable width were investigated for measuring the minimum interdental space. On the reconstructed cross-sectional images, labiolingual thickness of the bone was measured at the levels of 2, 5, 8, and 11 mm from the CEJ. The Kruskal-Wallis test, Mann-Whitney test with Bonferroni correction, Welch test, and Tukey's multiple analogy test were used to analyze the data. RESULTS: Mesiodistal and labiolingual distances between the roots in every measured region had the highest values at the levels of 8 and 11 mm from the CEJ. The highest measured values were related to the interdental region between the lateral incisor and canine teeth on both sides of the arch. There were no statistically significant differences between these values (P < .001). CONCLUSION: The lateral incisor-canine areas at the level of 8 mm from the CEJ are introduced as the optimal sites for placement of orthodontic mini-screws. In addition, the results recommend the application of mini-screws with 1.3-1.7 mm diameter and 5-7 mm length.

Fusion patterns of the spheno-occipital synchondrosis in the age range of 9-22: A computed tomography analysis.

OBJECTIVES: To assess the fusion patterns of the spheno-occipital synchondrosis (SOS) in the age range of 9-22 using CT and CBCT images of an Iranian population. SETTING/SAMPLE POPULATION: Spiral CT and CBCT scans of 763 subjects (459 males and 304 females) aged 9-22 were evaluated. The scans had to cover the cranial base area, and those with diseases affecting the bone density, cranial base masses and history of trauma were excluded. MATERIALS AND METHODS: Two oral and maxillofacial radiologists scored the images with regard to the status of SOS fusion based on a 5-stage system. Mann-Whitney, Kruskal-Wallis and Fisher's exact tests were used for data analysis. Age and SOS fusion stages were evaluated through Spearman correlation and linear regression methods (α = 0.01). RESULTS: The earliest age for onset of SOS fusion was 9 in both sexes. Open SOS could be observed until the age of 15 and 14 in males and females, respectively. The earliest age of complete fusion was 12 in males and 13 in females. Furthermore, there was a significant, positive correlation between age and the different stages of SOS fusion (P < .001). CONCLUSION: A significant correlation exists between age and the fusion stages of SOS, rendering it an appropriate means of age estimation during growth periods. Fusion of SOS begins approximately 2 years earlier in females; however, it ends at the age of 17 in both sexes. The fusion scar can be detected up to the age of 12 and 13 in males and females, respectively.

Fenestration and dehiscence in the alveolar bone of anterior maxillary and mandibular teeth in cone-beam computed tomography of an Iranian population.

BACKGROUND: The presence of dentoalveolar lesions such as fenestration and dehiscence has great clinical importance. This study was designed to determine the incidence of bony fenestrations and dehiscences associated with the anterior teeth by using cone-beam computed tomography images. MATERIALS AND METHODS: A total of 216 images (1189 teeth) were included in this cross-sectional study. The presence of fenestration and dehiscence at the buccal and lingual/palatal surfaces and also their relative levels on the roots of the teeth were determined. McNemar's, Chi-square, and Cochran's Q tests were used for data analysis. A value of P < 0.05 was considered to be statistically significant. RESULTS: The incidence of fenestration and dehiscence was 17.6% and 3.9%, respectively with the maxillary fenestrations being more prevalent (P < 0.0001). No significant differences were observed in the incidence of dehiscences between the jaws (P = 0.824) and among the tooth types (P = 0.689). The lesions were more frequent at the buccal surfaces (80%-92.5%). About 85.9% of the fenestrations occurred in the apical root thirds, whereas dehiscences had the highest prevalence in the cervical thirds. Fenestration and dehiscence incidences were significantly higher in females (P < 0.05). There was no significant difference among the age groups regarding these lesions. CONCLUSION: Fenestration and dehiscence were observed more on the buccal surfaces and also in the apical and cervical root thirds, respectively. Age had no significant influence on the occurrence of these lesions in contrast to the sex.

Effect of slice inclination and object position within the field of view on the measurement accuracy of potential implant sites on cone-beam computed tomography.

PURPOSE: The purpose of this study was to evaluate the accuracy of linear measurements in the horizontal and vertical dimensions based on object position and slice inclination in cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: Ten dry sheep hemi-mandibles, each with 4 sites (incisor, canine, premolar, and molar), were evaluated when either centrally or peripherally positioned within the field of view (FOV) with the image slices subjected to either oblique or orthogonal inclinations. Four types of images were created of each region: central/cross-sectional, central/coronal, peripheral/cross-sectional, and peripheral/coronal. The horizontal and vertical dimensions were measured for each region of each image type. Direct measurements of each region were obtained using a digital caliper in both horizontal and vertical dimensions. CBCT and direct measurements were compared using the Bland-Altman plot method. P values <0.05 were considered to indicate statistical significance. RESULTS: The buccolingual dimension of the incisor and premolar areas and the height of the incisor, canine, and molar areas showed statistically significant differences on the peripheral/coronal images compared to the direct measurements (P<0.05). Molar area height in the central/coronal slices also differed significantly from the direct measurements (P<0.05). Cross-sectional images of either the central or peripheral position had no marked difference from the gold-standard values, indicating sufficient accuracy. CONCLUSION: Peripheral object positioning within the FOV in combination with applying an orthogonal inclination to the slices resulted in significant inaccuracies in the horizontal and vertical measurements. The most undesirable effect was observed in the molar area and the vertical dimension.

Detection of peri-implant bone defects using cone-beam computed tomography and digital periapical radiography with parallel and oblique projection.

PURPOSE: To compare the diagnostic accuracy of cone-beam computed tomography (CBCT) with that of parallel (PPA) and oblique projected periapical (OPA) radiography for the detection of different types of peri-implant bone defects. MATERIALS AND METHODS: Forty implants inserted into bovine rib blocks were used. Thirty had standardized bone defects (10 each of angular, fenestration, and dehiscence defects), and 10 were defect-free controls. CBCT, PPA, and OPA images of the samples were acquired. The images were evaluated twice by each of 2 blinded observers regarding the presence or absence and the type of the defects. The area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were determined for each radiographic technique. The 3 modalities were compared using the Fisher exact and chi-square tests, with P<0.05 considered as statistical significance. RESULTS: High inter-examiner reliability was observed for the 3 techniques. Angular defects were detected with high sensitivity and specificity by all 3 modalities. CBCT and OPA showed similar AUC and sensitivity in the detection of fenestration defects. In the identification of dehiscence defects, CBCT showed the highest sensitivity, followed by OPA and PPA, respectively. CBCT and OPA had a significantly greater ability than PPA to detect fenestration and dehiscence defects (P<0.05). CONCLUSION: The application of OPA radiography in addition to routine PPA imaging as a radiographic follow-up method for dental implantation greatly enhances the visualization of fenestration and dehiscence defects. CBCT properly depicted all defect types studied, but it involves a relatively high dose of radiation and cost.