Assessment of bony changes in temporomandibular joint in patients using cone beam computed tomography - a cross sectional study.

BACKGROUND AND AIM: The aim of this study is to evaluate the changes in the temporomandibular joint (TMJ) in patients with temporomandibular disorder (TMD) and the relationship between age, sex, and types of TMJ change using Cone Beam Computed Tomography (CBCT). METHODS AND MATERIAL: CBCT records of 200 patients (123 women and 67 men) were retrieved and assessed. Right and left TMJs were evaluated separately, resulting in a total of 400 TMJs. The images were analyzed using On demand 3D Application The radiographic findings were classified as erosion, proliferative changes mainly, including flattening and osteophytes of the condyle, sclerosis, Ely cyst, hypoplasia and hyperplasia of the condyles, ankylosis, and joint cavity. Data analysis was performed using descriptive statistics, paired T-tests, and repeated measure ANOVA (Analysis of Variance) in SPSS Software. RESULTS: The most prevalent types of condylar bony changes observed was osteophyte (63.5%) followed by flattening of the articular surface (42%), erosion (40%), ankylosis (10%) and sclerosis (10%). 7.5% of joints showed hyperplastic condyles but only 2% showed hypoplasia. The least prevalent change observed was Ely Cyst (1%). Osteophyte was the most prevalent change observed in all age groups and both sexes except for men aged 31 ~ 50, where flattening was more frequent. A statistically significant difference was found between sex and prevalence of erosion in the age group of 10 ~ 30 (P = 0.001); as well as between sex and condylar hyperplasia in the same age group. CONCLUSION: Based on the findings of this research, the prevalence of bony changes of TMJ from highest to lowest is as follows: osteophyte, flattening of the articular surface, erosion, ankylosis, sclerosis, hyperplastic condyles, hypoplastic condyles and Ely Cyst. CBCT is an accurate 3 dimensional imaging modality for assessment of TMJ bony structures.

Evaluation of anatomical relationships in the mandibular third molar region based on its angulation and depth of impaction: a CBCT-based study.

PURPOSE: The aim of this study is to evaluate the relationship between the inclination/impaction depth and root proximity to the inferior alveolar canal/lingual plate on a millimeter scale using CBCT scans. METHODS: 340 CBCT scans of the mandibular third molar (M3) of 219 patients were evaluated for this cross-sectional study. After adjustment of the 3D orientation of the individual's jaws, the study variables including the angulation between M3 and second molar (M2)/occlusal plane (OP), and the distance of mesial (M)/distal (D) roots of M3 from the inferior alveolar canal (IAC) and lingual plate (LP) were measured. Winter's classification was used for the specification of teeth angulation. The vertical position of each M3 was then evaluated using the 3D view window (based on Pell & Gregory classification). The Spearman correlation coefficient was used for reporting the correlation between quantitative variables. The One-way ANOVA test and the Welch analysis were used for inter-group comparisons. Finally, a multivariant analysis of variances was performed. RESULTS: Most third molars had a mesioangular inclination (52.1%), and vertical inclination (25.9%) was in second place. There was no significant correlation between angulation and age or the D/LP. A strong positive correlation between M3:M2 and M3:OP was observed (0.983). Furthermore, there was a weak negative correlation between M/IAC or M/LP and angulation (- 0.16 and - 0.13, respectively). Concerning Winter's classification, the relationship between D/IAC and angulation was statistically significant (P = 0.003). Furthermore, teeth in position A had lesser inclination compared to those with B or C positions. Multivariate analysis revealed that there was no statistically significant relationship between particular combinations of inclination-impaction depth and proximity of the M3 roots to the IAC or LP (P = 0.211). CONCLUSIONS: The findings of the current study revealed that there is a strong correlation between M3:M2 and M3:OP. The D/IAC was the only variable that had a significant relationship with the angulation of these teeth. Moreover, the roots of horizontally inclined teeth with position A were the closest to the LP and the farthermost to the IAC.

Influential Factors in Buccal and Lingual Plate Perforation around Dental Implants Using Cone-Beam Computed Tomography.

This study determined the influential factors in buccal and lingual plate perforation around dental implants using cone-beam computed tomography (CBCT). In this retrospective, cross-sectional study, CBCT scans of dental implants taken for purposes not related to this study from 2017 to 2018 were retrieved from the archives of a private dental clinic. Demographic information, implant site, length, diameter, shape, and angulation, buccal and lingual plate thickness, buccolingual diameter of bone, and presence of crestal bone resorption were all assessed on CBCT scans. Data were analyzed using chi-squared, Mann-Whitney, Kruskal-Wallis, and independent t-tests. Of 604 implants, 88 had caused bone perforation in 41 females (46.6%) and 47 males (53.4%) with a mean age of 54.97 ± 13.99 years; 83% of perforations were in the maxilla; 55.7% of implants causing perforation were cylindrical and 44.3% were conical. The mean length and diameter of implants was 11.78 ± 1.91 mm, and 4.49 ± 0.76 mm, respectively; 38.9% of perforations were in the buccal and 18.2% in the lingual plate, and 42% were in the apical region. Crestal bone loss was noted in 58% of perforation cases. The mean angular deviation of implants was 19.13 ± 12.41°. Implant length and diameter had a significant association with the occurrence of perforation in the mandible (P < 0.05). Perforations had a higher frequency in the posterior maxilla, and mainly in the apical region. The buccal plate was thin in the anterior maxilla, with minimum thickness in the apical region. Lingual plate perforation had the highest frequency in the mandible.

The Anatomical Position and Size of Greater Palatine Foramen and Canal in an Iranian Sample Using Cone Beam Computed Tomography.

Detection of location of greater palatine foramen (GPF) and its anatomical variations are vital prior to posterior maxillary surgeries. The aim of this study is to determine the anatomical position and size of the greater palatine canal and GPF using cone beam computed tomography (CBCT) scan. To determine the anatomical foramen position, the posterior maxilla area was divided into five regions on the axial view (A to E from the mesial surface of the second molar to distal surface of third molar). The length of the canal was investigated on both coronal and sagittal views. Independent t-test was used to analyze the data. Among 80 females and 68 males, the anatomical position of the GPF was mainly located in region E on the left (55%) and the right (50%), and then, respectively, in region D and region C. The mean diameter of GPF was 4/48 mm on the left and 4/63 mm on the right side (P = 0/01). The average length of the canal on the coronal view was 29.46 mm on the left side and 29.75 mm on the right (P = 0.005). The average length of the canal on the sagittal view was 29.62 mm on the left and 30.02 mm on the right (P = 0.001). The anatomical position of the GPF was primarily located distal to the third maxillary molar. CBCT is a valuable diagnostic tool for evaluation of vital anatomic landmarks in the maxillofacial region prior to surgeries.

Quantitative Evaluation of Bone-Related Factors at the Implant Site by Cone-Beam Computed Tomography.

OBJECTIVES: Dental implant is a commonly used treatment modality for replacement of the missing teeth. The aim of the present study was to evaluate a number of bone-related factors at the implant site preoperatively by cone-beam computed tomography (CBCT). MATERIALS AND METHODS: A total of 400 implant sites were evaluated on CBCT images. The height, width, angle of residual ridge, thickness of cortical bone crest, and the ridge concavity were evaluated on cross sectional images at four regions: the anterior maxilla, anterior mandible, posterior maxilla, and posterior mandible. RESULTS: The highest thickness of cortical bone was observed in posterior mandible followed by anterior mandible, anterior maxilla, and posterior maxilla. In the mandible, the mean buccal concavity was higher in the anterior than in the posterior region (P = 0.0094). The measurements indicated that in both the maxilla (P = 0.0256) and mandible (P < 0.0001), the residual ridge width was lower in the anterior than in the posterior region; while the height of the residual ridge was higher in the anterior than in the posterior region in the mandible (P < 0.0001). In the maxilla, the remaining ridge angle in the anterior region was greater than that in the posterior region (P < 0.0001). CONCLUSION: Anatomical variations detected on CBCT results in personalized treatment planning considering best site and the best fixture in terms of size and position prior to implant fixture insertion.

Large Rhinolith Mimicking Atypical Odontogenic Pain: Case Report and Brief Review of the Literature.

Rhinoliths are rare calcified entities in the nasal fossa, frequently originating around a nidus near the midway point in the inferior meatus, where the passage is the narrowest. They can be clinically asymptomatic and undetected for years. In this study, we present a rare case of large rhinolith mimicking atypical odontogenic pain in a 40-year-old Caucasian female in the left nasal cavity. The lesion was detected in the CBCT and removed uneventfully.

A New Classification of Anterior Mandible Edentulous Ridge Based on Cone Beam Computed Tomography.

Purpose - Dental implants in the anterior mandible have become increasingly common due to popular prosthetic treatments. The aim of this study was to evaluate cone beam computed tomography (CBCT) images of mandibles from edentulous patients in need of anterior dental implants to present qualitative descriptions in the mental interforaminal region and to present a new classification. Material and Methods - A total of 180 (CBCT) scans of patients requiring implant installation in the anterior mandible for implant assisted overdenture treatment plan were evaluated regarding parameters such as ridge height, width, inclination, and undercuts. All assessments were performed on the cross-sectional images mesial to the mental foramen. Results - The most common ridge morphology was cylindrical (74.1%) followed by atrophic (19.4%) and undercut (6.4%). The prevalence of atrophic ridge was significantly higher in females and ridge with undercut was significantly more detected in males (P < 0.05). D1 and D2 bone types was detected higher in males than in females (P < 0.05). Conclusion - Cylindrical morphology was the most prevalent features of anterior mandible of edentulous patients. A CBCT scan is a useful diagnostic tool providing important information about anatomical structures and morphological variations in the sites of interest.

Anatomical variations in the interforaminal regions of candidates for implant-assisted overdentures: a cross-sectional CBCT analysis.

Implant-supported overdentures are becoming a common treatment modality, providing functional and esthetic results for patients in need of full-mouth rehabilitation. Because anatomical variations in the residual ridge affect treatment planning, the aim of this retrospective study was to present quantitative descriptions of the interforaminal region by evaluating a large series of cone beam computed tomographic (CBCT) images of the mandibles of edentulous patients in need of anterior dental implants. The sample included a total of 180 CBCT scans (360 sites) of patients requiring endosseous implant placement in the anterior region of the mandible for implant-assisted overdentures. The CBCT images were evaluated for parameters such as ridge height, width, angulation, and undercuts; crestal height; and corticocancellous bone ratios. The statistical analyses included the independent-samples t test and chi-square analysis. The mean (SD) ridge height was 18.16 (0.36) mm on the right side and 17.79 (0.38) mm on the left side and was significantly greater in men than in women (P = 0.02). Men also had a significantly greater cortical crest height than women (P = 0.01). The prevalence of ridge undercuts in the buccal cortex was 10.0% on the right side and 7.2% on the left side, and these undercuts had mean (SD) depths of 1.52 (0.62) mm and 1.48 (0.60) mm on the right and left sides, respectively. The ratio of cortical bone to cancellous bone was significantly greater in men than in women (P = 0.03). The mean (SD) ridge angle was 14.51 (6.54) degrees on the right side of the mandible and 13.05 (6.47) degrees on the left side, a statistically significant difference (P = 0.00). Moderate positive correlations were detected between the patient age and both the ridge widths (P = 0.00) and cancellous bone widths (P = 0.01). Moderate negative correlations were detected between the patient age and both ridge height and cortical crest height (P = 0.00). The widest ranges of variation belonged to ridge angle and ridge height, respectively, but the differentiation between the right and left sides was clinically insignificant. Knowledge of the patient's anatomical variations will allow the clinician to formulate an individualized treatment plan.

Effect of Amperage and Field of View on Detection of Vertical Root Fracture in Teeth with Intracanal Posts.

INTRODUCTION: This study sought to assess the effects of amperage (mA) and field of view (FOV) on intracanal metal post artifacts and the diagnostic parameters for detection of vertical root fracture (VRF) in teeth with intracanal posts. METHODS AND MATERIALS: In this diagnostic study, 80 human single-canal teeth were evaluated by cone-beam computed tomography (CBCT). Nickel chrome cast posts were placed into root canals after root canal therapy and canal preparation. In the test group, fracture was induced by an instron machine while no fracture was induced in the control group. Deterministic and probabilistic sensitivity and specificity values at different exposure settings were statistically analyzed using the one-way ANOVA and pairwise comparisons were performed by Tukey's test. RESULTS: Significant differences were found between the two groups in terms of deterministic (P<0.0001) and probabilistic (P<0.013) sensitivity and deterministic (P<0.037) and probabilistic (P<0.0001) specificity at different FOV and mA combinations. CONCLUSION: A smaller FOV and lower mA should be preferably used for detection of VRFs in teeth with intracanal posts.

Utility of a Newly Designed Film Holder for Premolar Bitewing Radiography.

INTRODUCTION: Bitewing radiography is a valuable technique for assessment of proximal caries, alveolar crest and periodontal status. Technical errors during radiography result in erroneous radiographic interpretation, misdiagnosis, possible mistreatment or unnecessary exposure of patient for taking a repeat radiograph. AIM: In this study, we aimed to evaluate the efficacy of a film holder modified from the conventional one and compared it with that of conventional film holder. MATERIALS AND METHODS: Our study population comprised of 70 patients who were referred to the Radiology Department for bilateral premolar bitewing radiographs as requested by their attending clinician. Bitewing radiographs in each patient were taken using the newly designed holder in one side and the conventional holder in the other side. The acceptability of the two holders from the perspectives of the technician and patients was determined using a 0-20 point scale. The frequency of overlap and film positioning errors was calculated for each method. RESULTS: The conventional holder had greater acceptability among patients compared to the newly designed holder (mean score of 16.59 versus 13.37). From the technicians' point of view, the newly designed holder was superior to the conventional holder (mean score of 17.33 versus 16.44). The frequency of overlap was lower using the newly designed holder (p<0.001) and it allowed more accurate film positioning (p=0.005). CONCLUSION: The newly designed holder may facilitate the process of radiography for technicians and may be associated with less frequency of radiographic errors compared to the conventional holder.

Effect of Metal Artifacts on Detection of Vertical Root Fractures Using Two Cone Beam Computed Tomography Systems.

INTRODUCTION: Vertical root fracture (VRF) is common in endodontically treated teeth. Conventional and digital radiographies have limitations for detection of VRFs. Cone-beam computed tomography (CBCT) offers greater detection accuracy of VRFs in comparison with conventional radiography. This study compared the effects of metal artifacts on detection of VRFs by using two CBCT systems. METHODS AND MATERIALS: Eighty extracted premolars were selected and sectioned at the level of the cemento enamel junction (CEJ). After preparation, root canals were filled with gutta-percha. Subsequently, two thirds of the root fillings were removed for post space preparation and a custom-made post was cemented into each canal. The teeth were randomly divided into two groups (n=40). In the test group, root fracture was created with Instron universal testing machine. The control teeth remained intact. CBCT scans of all teeth were obtained with either New Tom VGI or Soredex Scanora 3D. Three observers analyzed the images for detection of VRF. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for VRF detection and percentage of probable cases were calculated for each imaging system and compared using non-parametric tests considering the non-normal distribution of data. The inter-observer reproducibility was calculated using the weighted kappa coefficient. RESULTS: There were no statistically significant differences in sensitivity, specificity, PPV and NPV between the two CBCT systems. CONCLUSION: The effect of metal artifacts on VRF detection was not significantly different between the two CBCT systems.

Effect of Object Position in Cone Beam Computed Tomography Field of View for Detection of Root Fractures in Teeth with Intra-Canal Posts.

BACKGROUND: Vertical root fracture (VRF) is a common problem in endodontically treated teeth. Due to its poor prognosis, a reliable technique must be used to make an accurate diagnosis. Cone beam computed tomography (CBCT) has been recently introduced for maxillofacial imaging. Despite the high diagnostic value of this method, metal artifacts resulting from intra-canal posts still make the detection of VRFs challenging. OBJECTIVES: This study aimed to assess the effect of object position in the field of view (FOV) of CBCT on detection of VRFs in teeth with intra-canal posts. MATERIALS AND METHODS: The crowns of 60 extracted premolar teeth were cut at the level of cementoenamel junction (CEJ). Root canals were filled with gutta-percha and filling of the coronal 2/3 of the root canals was subsequently removed to fabricate intra-canal cast posts. The teeth were randomly divided into two groups of 30. Fracture was induced in group one using an Instron machine. Group two was considered as the control group with no fracture. All teeth were then randomly positioned and scanned in five different positions starting at the center of the FOV as well as right, left anterior and posterior relative to the center (3, 9, 12, and 6 O'clock) via the New Tom VGI CBCT unit. Two observers evaluated images for VRFs. Sensitivity and specificity of fracture diagnosis in each position was calculated in comparison with the gold standard. Wilcoxon test was used for data analysis. RESULTS: Considering deterministic and probabilistic diagnostic parameters, probabilistic sensitivity was similar in all positions; but probabilistic specificity of the center position (65.1%) was significantly higher than that of 6 and 12 O'clock positions. Considering the deterministic diagnostic parameters, the overall sensitivity and specificity values decreased in all positions in FOV, but sensitivity of the center position of FOV was significantly higher than that of other positions; specificity was significantly higher at the 3 O'clock position (58.5%). CONCLUSION: Concerning the positions in FOV, the center position is suitable for detection of VRF in teeth with intra-canal posts due to significantly higher sensitivity at this position. The 3 O'clock position would be suitable for assessment of intact teeth without fractures due to significantly higher specificity at this position.