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Statement of the problem: Presently, various imaging methods are available for the disclosure of proximal caries. Some recent studies have attempted to determine the diagnostic accuracy of available modalities, but they have shown variable results. Aim: This study was carried out to recognize and examine the correctness of cone-beam computed tomography (CBCT), regular radiographs and the nondirect digital system in the disclosure of interproximal caries. Materials and Method: In this observational tryout study, forty-two extracted non-cavitated, unrestored person molar and premolar teeth were placed in the blocks with proximal surfaces in touch. Then they were appraised by CBCT, formal radiographs and the nondirect digital system for the disclosure of interproximal caries. Four oral and maxillofacial radiologists used a 4-point scale to assess the pictures for the existence or absence of proximal caries. Caries depth was specified by histological examination. The gathered data were assessed by SPSS software using Weighted Kappa and Friedman test. Results: Statistics demonstrated that the accuracy of the indirect digital system was somewhat better than conventional systems. The accuracy of the indirect digital system was better than cone beam system, and this difference was statistically significant. Conclusion: The digital system was better than CBCT in the disclosure of proximal caries. The formal radiography fell in between the two other systems without a statistically significant deviation in detecting caries. Thus, CBCT is not advised to detect proximalcaries because of the higher radiation dose. [ABSTRACT FROM AUTHOR]

Background: This study aimed to assess the accuracy of two different endodontic guides for fiber post removal., Methods: In this in vitro study, 54 maxillary canine fiber posts were mounted on 36 maxillary stone casts; 18 teeth were mounted unilaterally, and 36 teeth were mounted bilaterally. Static endodontic guides were fabricated according to baseline cone-beam computed tomography (CBCT) and intraoral optical scans using Blue Sky software. In the single-sleeve endodontic guides group (SSG), two anterior and two posterior teeth were included in a 5-unit guide. In the double-sleeve endodontic guides group (DSG) group, the guide was passed through the midline to include both canine teeth and extended by 2 teeth posterior to the canine teeth bilaterally (a 10-unit guide). After drilling, postoperative CBCT scans were taken and superimposed on the virtually designed path, and the maximum coronal deviation (MCD) at the marginal entry point of the tooth, maximum apical deviation (MAD) at 10 mm apical to the tooth margin, and maximum angular deflection (MAnD) of the drill were calculated., Results: The mean MCD, MAD, and MAnD were 0.34 mm, 0.6 mm, and 2.32 degrees, respectively, in the SSG and 0.31 mm, 0.7 mm, and 2.37 degrees, respectively, in the DSG. The two groups were not significantly different from each other in terms of MCD (P = 0.573), MAD (P = 0.290), or MAnD (P = 0.896)., Conclusions: The accuracies of the two techniques, the extended double sleeve guide and the single sleeve guide, were comparable and thus DSG may be used for removal of fiber posts in adjacent or distant teeth., (© 2024. The Author(s).)

Background: Transgingival probing is conventionally used for gingival thickness (GT) measurement. However, invasiveness is a major drawback of transgingival probing. Thus, researchers have been in search of alternative methods for measurement of GT. This study compared the clinical efficacy of intraoral ultrasonography and transgingival probing for measurement of GT in different biotypes., Materials and Methods: This clinical trial was conducted on 34 patients requiring crown lengthening surgery. GT was measured at 40 points with 2- and 4-mm distances from the free gingival margin (FGM) of anterior and premolar teeth of both jaws in each patient by an intraoral ultrasound probe. For measurement of GT by the transgingival probing method, infiltration anesthesia was induced, and a #25 finger spreader (25 mm) was vertically inserted into the soft tissue until contacting bone. The inserted length was measured by a digital caliper with 0.01 mm accuracy. All measurements were made by an operator with high reliability under the supervision of a radiologist. Data were analyzed by t-test, Power and Effect Size formula, and intraclass correlation coefficient (ICC)., Results: The two methods were significantly different in measurement of GT in both thick and thin biotypes at 2- and 4-mm distances (P < 0.001). The two methods had a significant difference in both the mandible (P < 0.001) and maxilla (P < 0.001) and in both the anterior (P < 0.003) and premolar (P < 0.003) regions. Although the difference was statistically significant in t-tests, the power and effect formula proved it to be clinically insignificant. Also, the ICC of the two methods revealed excellent agreement., Conclusion: The results showed optimal agreement of ultrasound and transgingival probing for measurement of GT., Trial Registration: The study was approved by the ethics committee of Shahid Beheshti University of Medical Sciences on 2021-12-28 (IR.SBMU.DRC.REC.1400.138) and registered in the Iranian Registry of Clinical Trials on 2022-03-14 (IRCT20211229053566N1)., (© 2024. The Author(s).)

Background: This study intended to evaluate the association between several endodontic prognostic factors with the presence of periapical lesions (PLs), their volume, and bone characteristics including cortical bone destruction (CBD) and buccal plate bone height (BPBH) in root-filled molar teeth using cone-beam computed tomography., Methods: A collection of 143 scans of endodontically treated maxillary/mandibular first or second molars recorded over 8 years, were obtained from a specialized radiology center. Data on prognostic factors including tooth number, gender, jaw type, the status and number of missed canals, obturation length, restoration type, presence of a separated instrument, presence of a post or screw in the canals, and presence of perforation were collected. The assessed outcomes included PL presence, PL volume, CBD, and BPBH. The association between prognostic factors and outcomes was evaluated using multiple logistic regression models with adjusted covariates and multifactorial ANOVA at a significance level of 0.05., Results: A total of 282 molars from 82 women and 50 men with a mean age of 40.6 ± 12.27 were included. Among those, 139 teeth presented PL with a mean volume of 18.68 mm 3 . CBD was prevalent in 137 teeth and the mean BPBH appeared to be 9.45 mm. The presence of a missed canal (OR = 10.022, P < .05), underfilled canal (OR = 3.725, P < .05), overfilled canal (OR = 15.859, P = .018), and perforation (OR = 15.261, P = .013) was significantly associated with PLs. None of the prognostic factors could considerably contribute to the CBD (P > .05). The presence of a missed canal was positively associated with the PL volume (P < .05). Similarly, missed canals (P < .05), perforation (P < .05), and separated instruments (P = .004) were associated with a significantly reduced BPBH., Conclusions: Overfillings, perforations, missed canals, and underfillings were identified as remarkable predictors of PL, arranged in descending order of their respective impact. The only factor capable of significantly increasing the PL volume was the missed canal. In brief, obturation length errors, perforations, missed canals, and separated instruments were robustly correlated with endodontic failure, which highlights the importance of mitigating the potential for errors by following the fundamentals of endodontics., (© 2023. The Author(s).)

Background: Different imaging techniques, such as multi-detector computed tomography (MDCT) scan and cone beam computed tomography(CBCT), are used to check the structure of the nose before rhinoplasty. This study aimed to evaluate the accuracy of two imaging techniques, MDCT scan, and CBCT, in diagnosing structural Variations in rhinoplasty for the first time., Methods: This diagnostic accuracy study was conducted on 64 rhinoplasty candidates who complained of snoring and sleep apnea or had a positive result in the examination with Cottle's maneuver or modified Cottle technique between February 2021 and October 2022 at 15- Khordad Hospital affiliated to Beheshti University of Medical Sciences. Before rhinoplasty, patients were randomly assigned to one of the CT and CBCT techniques with an equal ratio. Scans were assessed for the presence of Nasal septum deviation (NSD), Mucocele, Concha bullosa, and nasal septal spur by two independent radiologists. The findings of the two methods were evaluated with the results during rhinoplasty as the gold standard., Results: NSD was the most common anatomical variation based on both imaging techniques. The accuracy of CBCT for diagnosing Nasal Septum Deviation and Mucocele was 80% and 75%, respectively. The sensitivity, specificity, and accuracy of CBCT in detecting Concha bullosa were 81.3% and 83.3%, respectively. The Kappa coefficient between CBCT and intraoperative findings for diagnosing NSD and Concha Bullosa was 0.76 and 0.73, respectively (p < 0.05)., Conclusion: CBCT can be considered a suitable method with high accuracy and quality to evaluate the anatomical variations before rhinoplasty., (© 2023. The Author(s).)

Pulp canal calcification (PCC) is common in patients with dentinogenesis imperfecta (DGI). We present endodontic management of multiple anterior and posterior teeth with PCCs in a patient with DGI type II using guided endodontics. A 26-year-old female patient was diagnosed with DGI type II. Clinical examination revealed palatal cusp fracture in tooth #13, microcracks in tooth #14, and a sinus tract in the maxillary right buccal vestibule related to tooth #13. Periapical radiographs revealed PCCs in all teeth, and periapical radiolucencies in several teeth. Due to difficult negotiation of canal orifices, guided endodontic approach was planned. Cone-beam computed tomography (CBCT) was requested and obtained. Intraoral scanning was performed, and CBCT and intraoral scanning data were superimposed. A template was designed and 3D printed. The root canal orifices were successfully negotiated and endodontic treatments were successfully accomplished. At the 1-year follow-up, the endodontically treated teeth were asymptomatic, and periapical lesions were healing., Competing Interests: None.

Statement of the Problem: Early detection of caries and the extent of carious lesions for appropriate treatment planning are very important and lead to introduction of new diagnostic tools., Purpose: This study aimed to compare the diagnostic accuracy of VistaCam IX Proxi and bitewing radiography for detection of posterior interproximal caries., Materials and Method: This in vitro study was performed on 40 extracted posterior teeth without cavitated carious lesions. Bitewing radiographs were obtained, infrared (IR) examination was performed, and the teeth were sectioned for histopathological analysis under a stereomicroscope as the gold standard for detection of caries and determination of the extent of carious lesions. Data were analyzed with Cohen's kappa statistic, and Wilcoxon rank sum test., Results: The specificity of VistaCam IX Proxi and bitewing radiography was 71.4% and 87.7%, respectively. Their sensitivity was 100% and 40% for enamel caries, 72.8% and 54.5% for external half dentin caries, and 82.3% and 58.8% for internal half dentin caries, respectively ( p = 0.048)., Conclusion: Bitewing radiography had a higher specificity and lower rate of false positive results. However, VistaCam IX Proxi had higher sensitivity for caries detection with lower rate of false negative results. Considering the higher sensitivity and significantly lower frequency of false negative results by VistaCam IX Proxi, it may be reliably used for caries detection specially enamel caries, and can serve as an adjunct to bitewing radiography., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright: © Journal of Dentistry.)

Introduction: Vaccines stand amongst the most effective medical interventions for the management of infectious diseases, and are pivotal tools for public health. The acceptance of vaccines is heavily influenced by perceptions of efficacy, safety and other modifiable factors., Purpose: This cross-sectional study sought to identify and examine the modifiable factors that can help address COVID-19 vaccine hesitancy and acceptance among cancer patients., Methods: The study was conducted between February and April 2021 using an online survey questionnaire comprising of four domains. The survey was administered to cancer patients in Jordan., Results: Among the 1,029 cancer patients who completed the online questionnaire (response rate= 73%), 58% (n=597) expressed willingness (intent) to take the vaccine. Notably, 72.5% (n=433) of those intending to take the vaccine were currently undergoing treatment. Knowledge and awareness played a significant role, with 54.3% considering them essential for vaccine acceptance. Fear of infection significantly influenced vaccine acceptance (p<0.001), with 66.8% expressing concern about potential infections. Peer encouragement was also a crucial factor, as 82.4% regarded it as an important driver for influencing vaccine acceptance (p<0.001)., Conclusion: Peer encouragement, awareness, and fear emerged as the primary modifiable factors associated with greater vaccine acceptance by patients with active malignancies. Study results suggest that providing personalized and tailored information about vaccinations, focusing on safety and potential interactions with cancer and its treatment, are potentially excellent strategies for improving vaccine acceptance among cancer patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 AlMasri, Al Masri, Darwish, Ammar and Safi.)

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., (© 2023. The Author(s).)

Background: This study was conducted to compare the pain levels in patients and the clinical efficacy of grafts obtained using two techniques, namely de-epithelialized gingival graft (DGG) and subepithelial connective tissue graft (SCTG), in combination with coronally advanced flap (CAF) for the treatment of multiple adjacent gingival recessions., Methods: Twelve patients were treated using DGG+CAF on one side and SCTG+CAF on the other. The patients' pain levels at the surgical site, the number of analgesics taken on days 3 and 7, the mean root coverage (MRC), the percentage of complete root coverage (CRC), color match, and gingival thickness (GT) at the graft recipient site were evaluated 6 months after surgery., Results: The total number of analgesics taken during the 7-day period after surgery and pain levels at the surgical site from day 3 to day 7 were significantly higher in the DGG+CAF group compared to the SCTG+CAF group ( P =0.001). In the 6-month follow-up, color match and CRC were significantly higher in the SCTG+CAF group, while GT was significantly higher in the DGG+CAF group. There was no significant difference in MRC between the two groups., Conclusion: The pain and analgesic consumption levels were higher in the DGG+CAF group compared to the SCTG+CAF group, and the recipient site had a weaker color match. However, this technique can lead to a greater increase in the thickness of the grafted area., Competing Interests: The authors declare that they have no competing interests., (© 2023 The Author(s).)

Introduction: This study aimed to assess the quantity and quality of available bone to provide the autologous bone graft from mandibular ramus., Material and Methods: CBCT scans were collected and mandibular ramus was evaluated by measuring a variety of parameters including volume, bone height, cortical, and cancellous bone thickness. Data analysis was performed using descriptive statistics and inferential statistics. We used the Kolmogorov-Smirnov test for the evaluation of data normality. We then applied Pearson correlation and independent t -test for normal variables, and Spearman and Mann-Whitney correlation tests for abnormal variables. Statistical analysis was performed using SPSS version 19 and P value < 0.05 was considered significant., Results: A total of 52 women and 32 men (aged 21 to 70) were included in this study. The mean bone volume was 2.7 ± 0.70 cm 3 [95%confidence interval (CI) 1.3-4.5]. The mean bone density in the middle section was 1016.36 ± 231.58 Gy value (95% CI 475.6-1520.9). Kolmogorov-Smirnov test revealed that the variables such as apical cortical/cancellous ratio ( P  = 0.005), middle-cancellous bone thickness ( P = 0.016), and middle cortical/cancellous ratio ( P  = 0.005) were abnormal and the rest were normal. Bone density, as well as the amount of cortical bone in the middle and apical regions, had a significant reverse correlation with age ( P  < 0.001)., Conclusion: The volume, density, and cortical/cancellous ratio are independent of sex. The reverse relationship between age and bone density, as well as the amount of cortical bone in several parts, indicates a decrease in bone quality with aging., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© The Association of Oral and Maxillofacial Surgeons of India 2021.)

Objective: This study sought to compare the thickness of hard and soft tissues between edentulous and contralateral tooth sites., Materials and Methods: This split-mouth study evaluated 153 partially edentulous patients. The measurements were made on cone-beam computed tomography (CBCT) scans. The soft tissue thickness was measured at the cementoenamel junctional (CEJ) level, and at 2, 4, and 6 mm apical to the CEJ in the facial and palatal aspects. The bone thickness of the opposite quadrant was also recorded at 2, 4, and 6 mm apical to the CEJ. The Mann-Whitney U test and the Spearman's rank correlation coefficient were applied for further statistical analyses., Results: At the edentulous sites, significant soft tissue loss was noted at the CEJ level ( p  < 0.0001) and a considerable gain was noted at 2, 4, and 6 mm apical to the CEJ ( p  = 0.004, p  < 0.0001, p  ≤ 0.0001, respectively). A significant hard tissue loss was noted at 2 mm apical to the CEJ but a significant hard tissue gain was observed at the edentulous sites ( p  < 0.0001). The soft tissue gain at 6 mm apical to the CEJ was significantly associated with an increase in buccolingual diameter ( p  = 0.004) while the hard tissue loss at 2 mm apical to the CEJ was significantly correlated with a reduction in buccolingual diameter ( p  = 0.020)., Conclusion: Different amounts of tissue thickness alterations occurred in different levels of socket., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest to this study., (© The Association of Oral and Maxillofacial Surgeons of India 2021.)

Introduction: Canines are the second most common tooth in terms of impaction. Impacted teeth can be associated with some different indices of dental arch and dentoalveolar structures. The aim of this study was to evaluate maxillary arch width as well as volume and depth of palate in patients with maxillary impacted canine by cone beam computed tomography (CBCT)., Methods: In this cross-sectional study, 45 CBCT images of patients with unilateral maxillary impacted canines were examined. All patients had palatally impacted canines. Three parameters of maxillary arch width, palatal volume and palatal depth were assessed using axial and sagittal incisions on the CBCT images. Then all the measurements on the impacted side were compared with the non-impacted side. Data were entered into SPSS software and paired sample t-test and Student's t-test were used to comparison. The significance level of 0.05 was considered., Results: The maxillary arch width on the impacted side was significantly less than the normal side (P < 0.001). The mean depth of the palate was 14.86 ± 3.53 mm. There was a significant correlation between canine impaction and Palatal volume (R = 0.728 and P-value< 0.001), but no significant correlation between canine impaction and Maxillary arch width was shown (R = 0.15 and p-value = 0.326)., Conclusion: The impacted canine was significantly associated with a reduction in the width of the maxillary arch on the affected side, and it made no difference if the impacted side was left or right. Also, impacted canine teeth were significantly associated with volume reduction on the affected side., Competing Interests: The authors declare no conflict of interest., (© 2022 The Authors.)

Materials and Methods: In this in vitro experimental study, titanium implants, teeth with cobalt-chromium (Co-Cr) intracanal posts, and teeth with mesio-occluso-distal (MOD) amalgam restorations were placed in an empty socket of the extracted third molar of a human mandible. These metallic materials were differently arranged in the exomass (zone outside of the FOV). A polypropylene tube containing dipotassium phosphate was placed in the empty socket of the right canine tooth in a dry human mandible. CBCT scans were taken with a NewTom VGI (Verona, Italy) scanner using a 6 × 6 cm and an 8 × 8 cm FOV. The histogram tool of OnDemand software (Cybermed, Seoul, Korea) was used to select circles with a 1.5 mm diameter as the (ROI) at the center of the homogenous solution of dipotassium phosphate tube on the axial plane. The mean gray value (GV) and its standard deviation (SD) in the region of interest (ROI) were calculated ( P > 0.05). The data were analyzed by SPSS 26., Results: The reduction in the size of the FOV significantly decreased the mean GV ( P < 0.001). Metal objects in the exomass significantly decreased the mean GV ( P < 0.001), and minimum mean GV and maximum SD were recorded for amalgam, followed by Co-Cr intracanal posts, and titanium implants. The unilateral presence of a metal object was associated with a higher mean GV and lower SD ( P < 0.001)., Conclusion: Using a smaller FOV increases the size of the exomass, which may negatively affect the image quality. Metal objects in the exomass decrease the GV of CBCT scans and adversely affect the image quality., Competing Interests: The authors declare that there are no conflicts interests., (Copyright © 2022 Yaser Safi et al.)

Purpose: The aim of this study was to introduce a category of jaw lesions comprising cysts and tumors associated with scalloped borders., Materials and Methods: General search engines and specialized databases including Google Scholar, PubMed, PubMed Central, and Scopus, as well as an authoritative textbook, were used to find relevant studies by using keywords such as "jaw lesion," "jaw disease," "scalloping," "scalloped border," "scalloped margin," "irregular border," and "irregular margin." Out of 289 articles, 252 records were removed because they were duplicates, did not have a relevant title, or did not mention the frequency of findings described using the term "scalloped border." Finally, 37 closely related articles were chosen., Results: According to the relevant literature, scalloped borders are found most frequently in ameloblastoma, followed by simple bone cyst, central giant cell granuloma, odontogenic keratocyst, and glandular odontogenic cyst., Conclusion: The lesions most frequently reported to have scalloped borders are ameloblastoma, central giant cell granuloma, odontogenic keratocyst, simple bone cyst, and glandular odontogenic cyst., Competing Interests: Conflicts of Interest: None, (Copyright © 2022 by Korean Academy of Oral and Maxillofacial Radiology.)

Background: Artifacts fault image quality but handling several factors can affect it. This study was conducted to investigate the effect of object size on artifacts in cone-beam computed tomography systems., Methods: Five phantoms, each containing a titanium implant in a sheep bone block, were fabricated of various sizes ranging from XS to XL: The M phantom was the same size as the device's field of view (FOV). The L and XL phantoms were 20 and 40% larger than the FOV while the S and XS phantoms were 20 and 40% smaller than FOV, respectively. Ballistic gelatin was used to fill the phantoms. Phantoms were scanned by NewTom VGI and HDXWill Q-FACE. The mean and standard deviation (SD) of gray values in each 120 ROI was obtained by OnDemand software. The contrast to noise ratio (CNR) was also calculated., Results: The gray value in S and M phantoms were more homogenous. The lowest SD value (10.20) was found in S phantom. The highest value for SD (125.16) was observed in XL phantom. The lowest (4.47) and highest (9.92) CNR were obtained in XL and S phantoms, respectively. HDXWill Q-FACE recorded a higher SD and a lower CNR than NewTom VGI (P < 0.05)., Conclusion: Object dimensions of the FOV size or up to 20% smaller provided better image quality. Since the dimensions of soft tissue in most patients are larger than the selective FOV, it is recommended that in CBCT artifacts studies, an object with dimensions closer to the patient's dimensions be used to better relate the results with the clinical condition, because the sample dimensions affect the amount of artifacts., (© 2022. The Author(s).)

Background: The maxillary palatine process (MPP) is an excellent source of autogenous bone transplants for anterior maxillary reconstruction. This research aimed to determine the quantity and quality of accessible MPP as a donor location., Methods: Cone-beam computed tomography (CBCT) scans of patients referred to the School of Dentistry were evaluated by a certified examiner. The harvestable MPP was defined as the space between the distal surfaces of maxillary first premolars. OnDemand 3D Imaging software was used to determine bone properties. SPSS software was used to investigate the following variables: Bone characteristics are correlated with age and gender, accessible volume, and palatal width and height. P <0.05 was defined as the level of statistical significance., Results: This study was performed on CBCT scans of 81 subjects (41 females and 40 males). MPP volume and palatal heights were 1.33±0.53 cm3 and 20.86±5.51 mm, respectively. Maximum bone density was observed around lateral incisors. Palatal width was 33.81±2.42 mm between canines and 41.81±2.66 mm between premolars. The MPP volume was significantly greater in males ( P <0.001). Additionally, there was a positive correlation between the volume and palatal width ( P <0.05)., Conclusion: Within the constraints of this research, there is a limited supply of MMP accessible for use as a graft source, and it is best suited for treating localized bone lesions. The favorable link between palatal breadth and harvestable volume aids the surgeon in estimating the quantity of bone accessible during the first evaluation., Competing Interests: The authors declare that they have no known competing and financial interests or personal relationships that could have influenced the work reported in this paper., (© 2022 The Author(s).)

Purpose: Dental implants are widely used for the rehabilitation of edentulous sites. This study investigated the occurrence of dental implant malpositioning as shown on post-implantation cone-beam computed tomography (CBCT) and to identify related factors., Materials and Methods: Samples with at least 1 malpositioned dental implant were collected from a central radiology clinic in Tehran, Iran from January 2017 to January 2019. Variables such as demographic characteristics, length and diameter of implants, type of implant, sites of implant insertion, different types of implant malpositioning problems (cortical plate perforation, interference with anatomical structures), angulation of the implant, and the severity of malpositioning were assessed. In addition, the incidence of implant fracture and over-drilling was evaluated. Data were statistically analyzed using the chi-square test, 1-sample t-test, and Spearman correlation coefficients., Results: In total, 252 patients referred for implant postoperative CBCT evaluations were assessed. The cases of implant malpositioning included perforation of the buccal cortical plate (19.4%), perforation of the lingual cortical plate (14.3%), implant proximity to an adjacent implant (19.0%), implant proximity to an adjacent tooth (3.2%), interference with anatomical structures (maxillary sinus: 18.3%, mandibular canal: 11.1%, nasal cavity: 6.3%, mental foramen: 5.6%, and incisive canal: 0.4%). Implant fracture and over-drilling were found in 1.6% and 0.8% of cases, respectively. Severity was categorized as mild (9.5%), moderate (35.7%), severe (37.7%), and extreme (17.1%), and 52.4% of implants had inappropriate angulation., Conclusion: CBCT imaging is recommended for detecting dental implant malpositioning. The most common and severe type of malpositioning was buccal cortex perforation., Competing Interests: Conflicts of Interest: None, (Copyright © 2021 by Korean Academy of Oral and Maxillofacial Radiology.)

Background: Bone volume plays a pivotal role in the success of dental implant treatment. Autogenous bone grafts should be harvested from reliable sites in the maxillofacial region. This study sought to assess the quantity and quality of bone in the mandibular symphysis for autogenous bone graft harvesting using cone-beam computed tomography (CBCT)., Methods: This cross-sectional study evaluated the CBCT scans of 78 adults presenting to three oral and maxillofacial radiology centers. The vertical (VD) and horizontal (HD) alveolar bone dimensions, cortical thickness (CT), and cancellous to cortical bone ratio (C/C) were measured in the interforaminal region of the mandible at the sites of central incisor to first premolar teeth. The interforaminal distance (ID) and the anterior loop length were also measured. Nonparametric statistical tests were used to analyze the data with respect to sex, age, and tooth position., Results: The median VD, HD, and CT of the symphysis were 20.21 (3.26), 4.13 (0.37), and 2.25 (0.23) mm, respectively. The median C/C was 1.51 (0.11). The median ID was 52.24 (8.24) mm, and the median anterior loop length was 1.82 (1.06) mm. Significant differences were observed in all parameters among different teeth. Most of the measured parameters were greater in males compared with females. There were significant differences in ID, VD, and CT between different age groups., Conclusions: The quantity and quality of the available bone in the mandibular symphysis for bone graft harvesting vary by gender, age, and harvesting site, necessitating careful preoperative evaluation., (© 2021. The Author(s).)

Purpose: The mastoid region is ideal for studying sexual dimorphism due to its anatomical position at the base of the skull. This study aimed to determine sex in the Iranian population based on measurements of the mastoid process using different data mining algorithms., Materials and Methods: This retrospective study was conducted on 190 3-dimensional cone-beam computed tomographic (CBCT) images of 105 women and 85 men between the ages of 18 and 70 years. On each CBCT scan, the following 9 landmarks were measured: the distance between the porion and the mastoidale; the mastoid length, height, and width; the distance between the mastoidale and the mastoid incision; the intermastoid distance (IMD); the distance between the lowest point of the mastoid triangle and the most prominent convex surface of the mastoid (MF); the distance between the most prominent convex mastoid point (IMSLD); and the intersecting angle drawn from the most prominent right and left mastoid point (MMCA). Several predictive models were constructed and their accuracy was compared using cross-validation., Results: The results of the t-test revealed a statistically significant difference between the sexes in all variables except MF and MMCA. The random forest model, with an accuracy of 97.0%, had the best performance in predicting sex. The IMSLD and IMD made the largest contributions to predicting sex, while the MMCA variable had the least significant role., Conclusion: These results show the possibility of developing an accurate tool using data mining algorithms for sex determination in the forensic framework., Competing Interests: Conflicts of Interest: None, (Copyright © 2020 by Korean Academy of Oral and Maxillofacial Radiology.)

Purpose: The aim of this study was to review the common conditions associated with mandibular canal widening., Materials and Methods: General search engines and specialized databases including Google Scholar, PubMed, PubMed Central, Science Direct, and Scopus were used to find relevant studies by using the following keywords: "mandibular canal," "alveolar canal," "inferior alveolar nerve canal," "inferior dental canal," "inferior mandibular canal," "widening," "enlargement," "distension," "expansion," and "dilation.", Results: In total, 130 articles were found, of which 80 were broadly relevant to the topic. We ultimately included 38 articles that were closely related to the topic of interest. When the data were compiled, the following 7 lesions were found to have a relationship with mandibular canal widening: non-Hodgkin lymphoma, osteosarcoma, schwannoma, neurofibroma, vascular malformation/hemangioma, multiple endocrine neoplasia syndromes, and perineural spreading or invasion., Conclusion: When clinicians encounter a lesion associated with mandibular canal widening, they should immediately consider these entities in the differential diagnosis. Doing so will help dentists make more accurate diagnoses and develop better treatment plans based on patients' radiographs.

Purpose: This study reviewed the common conditions associated with displacement of inferior alveolar nerve canal., Materials and Methods: General search engines and specialized databases including Google Scholar, Pub Med, Pub Med Central, Science Direct, and Scopus were used to find relevant studies by using keywords such as "mandibular canal", "alveolar canal", "inferior alveolar nerve canal", "inferior dental canal", "inferior mandibular canal" and "displacement"., Results: About 120 articles were found, of which approximately 70 were broadly relevant to the topic. We ultimately included 37 articles that were closely related to the topic of interest. When the data were compiled, the following 8 lesions were found to have a relationship with displacement of mandibular canal: radicular/residual cysts, dentigerous cyst, odontogenic keratocyst, aneurysmal bone cyst, ameloblastoma, central giant cell granuloma, fibrous dysplasis, and cementossifying fibroma., Conclusion: When clinicians encounter a lesion associated with displaced mandibular canal, they should first consider these entities in the differential diagnosis. This review would help dentists make more accurate diagnoses and develop better treatment plans according to patients' radiographs.

Diagnosis of oral white lesions might be quite challenging. This review article aimed to introduce a decision tree for oral white lesions according to their clinical features. General search engines and specialized databases including PubMed, PubMed Central, EBSCO, Science Direct, Scopus, Embase, and authenticated textbooks were used to find relevant topics by means of MeSH keywords such as "mouth disease", "oral keratosis", "oral leukokeratosis", and "oral leukoplakia". Related English-language articles published since 2000 to 2017, including reviews, meta-analyses, and original papers (randomized or nonrandomized clinical trials; prospective or retrospective cohort studies), case reports, and case series about oral diseases were appraised. Upon compilation of data, oral white lesions were categorized into two major groups according to their nature of development: Congenital or acquired lesions and four subgroups: Lesions which can be scraped off or not and lesions with the special pattern or not. In total, more than 20 entities were organized in the form of a decision tree in order to help clinicians establish a logical diagnosis by a stepwise progression method., Competing Interests: The authors declare no conflicts of interest.

Introduction: This study sought to assess root canal morphology of maxillary second molars regarding age and gender in an Iranian population using cone-beam computed tomography (CBCT)., Methods and Materials: Totally, 157 maxillary second molars of patients presenting to a radiology clinic were evaluated on CBCT scans. Tooth length, number of roots, root fusion, coronal and sagittal root deviation, number of canals per root, prevalence of second mesiobuccal canal, root canal morphology according to the Vertucci's classification and the correlation of these variables with age and gender were evaluated. Data were analyzed using the Mann Whitney U, Kruskal Wallis and Fisher's exact tests., Results: Of 157 teeth, 98 belonged to females and 59 to males. The mean tooth length was significantly greater in males than in females ( P =0.002) and it was shorter in 50-60 years old group. The rate of root fusion was 18.6%. Distobuccal and palatal roots were mainly straight in both sagittal and coronal planes while mesiobuccal roots mostly had a distal-buccal deviation; 67.5% of the teeth had four canals. Number of canals was significantly correlated with gender and was higher in males ( P <0.05). The most prevalent canal type was type VI in second mesiobuccal, and type V in palatal and distobuccal canals. The most common types in mesiobuccal canal were types I, VI and II, respectively. In the remaining two roots, type I was the most common., Conclusion: Root and canal morphology of the maxillary second molars in Iranian population showed features different from those in other populations., Competing Interests: ‘None declared’.

Death was the most important side effect of anaesthesia in dentistry. In this article we reviewed more than 20 studies with adequate data focusing on death associated with dental procedures since 1955 and found 218 deaths out of 71,435,282 patients (3 deaths per 1,000,000 persons) with the mortality rate of 1:327,684. In addition, mortality rate per million has dropped to half (6.2 per 1,000,000 vs. 3 per 1,000,000) since 1955 till the last report in 2012 without any sex predilection. In children, most cases died in the age of two to five years. Hypoxia was the most common cause of death, and cardiovascular, respiratory, and endocrine disorders, hepatic cirrhosis, septicaemia, and bacterial endocarditis were the most frequent underlying systemic disease in deceased patients. Although rare death following general anaesthesia in dentistry, is a critical side effect mostly seen in patients with compromised health condition. Therefore, appropriate case selection in regard with patients' general health status as well as standard technical and equipment conditions are mandatory to diminish the risk of death during dental anaesthesia.

Diagnosis of peripheral oral exophytic lesions might be quite challenging. This review article aimed to introduce a decision tree for oral exophytic lesions according to their clinical features. General search engines and specialized databases including PubMed, PubMed Central, Medline Plus, EBSCO, Science Direct, Scopus, Embase, and authenticated textbooks were used to find relevant topics by means of keywords such as "oral soft tissue lesion," "oral tumor like lesion," "oral mucosal enlargement," and "oral exophytic lesion." Related English-language articles published since 1988 to 2016 in both medical and dental journals were appraised. Upon compilation of data, peripheral oral exophytic lesions were categorized into two major groups according to their surface texture: smooth (mesenchymal or nonsquamous epithelium-originated) and rough (squamous epithelium-originated). Lesions with smooth surface were also categorized into three subgroups according to their general frequency: reactive hyperplastic lesions/inflammatory hyperplasia, salivary gland lesions (nonneoplastic and neoplastic), and mesenchymal lesions (benign and malignant neoplasms). In addition, lesions with rough surface were summarized in six more common lesions. In total, 29 entities were organized in the form of a decision tree in order to help clinicians establish a logical diagnosis by a stepwise progression method.

Introduction: The purpose of this study was to investigate the root and canal morphology of maxillary first molars with regards to patients' age and gender with cone-beam computed tomography (CBCT)., Methods and Materials: A total of 149 CBCT scans from 92 (67.1%) female and 57 (31.3%) male patients with mean age of 40.5 years were evaluated. Tooth length, presence of root fusion, number of the roots and canals, canal types based on Vertucci's classification, deviation of root and apical foramen in coronal and sagittal planes and the correlation of all items with gender and age were recorded. The Mann Whitney U, Kruskal Wallis and Fisher's exact tests were used to analyze these items., Results: The rate of root fusion was 1.3%. Multiple canals were present in the following frequencies: four canals 78.5%, five canals 11.4% and three canals 10.1%. Additional canal was detected in 86.6% of mesiobuccal roots in which Vertucci's type VI configuration was the most prevalent followed by type II and I . Type I was the most common one in distobuccal and palatal roots. There was no statistically significant difference in the canal configurations in relation to gender and age as well as the incidence root or canal numbers ( P >0.05). The mean tooth length was 19.3 and 20.3 mm in female and male patients, respectively which was statistically significant ( P <0.05). Evaluation of root deviation showed that most commonly, a general pattern of straight-distal in the mesiobuccal and straight-straight for distobuccal and palatal roots occurred. In mesiobuccal roots, straight and distal deviations were more dominant in male and female, respectively ( P <0.05). The prevalence of apical foramen deviation in mesiobuccal and palatal roots statistically differed with gender., Conclusion: The root and canal configuration of Iranian population showed different features from those of other populations.

Background: Detection of foreign bodies (FBs) is challenging. Selection of a fast and affordable imaging modality to locate the FB with minimal patient radiation dose is imperative., Objectives: This study sought to compare four commonly used imaging modalities namely cone beam computed tomography (CBCT), magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound (US) for detection of FBs in the head and neck region., Materials and Methods: In this in vitro study, iron, glass, stone, wood, asphalt, and tooth samples measuring 0.1 × 0.5 × 0.5 cm were placed in the tongue muscle, soft tissue-bone interface and nasal cavity in a fresh sheep's head and subjected to MRI, US, CT and CBCT. A total of 20 images were captured by each imaging system from the six materials in the afore-mentioned locations. The images were observed by an expert oral and maxillofacial radiologist and a general radiologist. To assess reliability, 20 images were randomly observed by the observers in two separate sessions. The images were classified into three groups of good visibility, bad visibility and invisible. The data were analyzed using SPSS version 18, Wilcoxon Signed Rank, Pearson chi square, and Fisher's exact tests., Results: All FBs in the tongue and at the soft tissue-bone interface had good visibility on US (P = 1.00). Also, CBCT and CT had significantly different performance regarding FB detection (P < 0.001). All wooden samples in the nasal cavity were invisible on CT scans; while, only 20% of them were invisible on CBCT scans. MRI showed significant differences for detection of FBs in the three locations (P < 0.001). MRI could not locate iron samples due to severe artifacts and only showed their presence (bad visibility) but other FBs except for wood and tooth in the nasal cavity (100% invisible) had good visibility on MRI., Conclusions: Ultrasound is recommended as the first choice when FB is located within the superficial soft tissues with no bone around it. In case of penetration of FB into deeper tissues or beneath bone, CT or CBCT are recommended. Otherwise, considering lower dose, CBCT is preferred over CT. We can use MRI if the FB is not ferromagnetic. However, CT is the first choice in emergency situations because of higher sensitivity.

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.

Background: Osteoma cutis is a rare soft tissue ossification of cutaneous tissue and may be primary or secondary. In the majorityof cases it is clinically asymptomatic and may detected incidentally on radiographic examination. Cone beam computed tomography (CBCT) has can be of great assistance in the detection of this asymptomatic lesion., Objectives: In this retrospective study, the prevalence and different radiographic appearance of osteoma cutis was evaluated., Materials and Methods: A total of 6,500 CBCT images were evaluated for the presence of osteoma cutis. Ectopic existence of calcified tissue within the soft tissue of the dermis or epidermis that was incompatible with the calcification of other anatomic structures or soft tissue calcifications was considered to be osteoma cutis. Accordingly, the detected patterns were divided into four distinct groups: (1) a single nodule, (2) plate-like lesion, (3) single or multiple depth lesion(s), trans-epidermal, and (4) multiple, disseminated lesions of various sizes known as multiple miliary. The data were evaluated in terms of prevalence and variations. The frequency, total prevalence, percentage and the prevalence of different radiographic forms of this lesion were calculated., Results: One hundred and forty eight (2.27%) cases of 6,500 evaluated tomograms had osteoma cutis. Of these, 5 (0.07%) were in the form of a single nodule, 4 (0.06%) were single, plate-like lesions, 7 (0.1%) were multiple plate-like lesions, 2 (0.03%) were in the form of a deep thread-like lesion, and 130 (2%) presented as multiple disseminated lesions., Conclusion: According to the radiographic views, osteoma cutis may be categorized into single nodular, single or multiple plate- like, deep, and multiple disseminated forms. Of the mentioned radiogarphic patterns, the multiple disseminated form (miliary) hada higher prevalence in our study. CBCT images enable accurate evaluation of the nature and frequency of osteoma cutis.

Diagnosis of oral ulcerative lesions might be quite challenging. This narrative review article aims to introduce an updated decision tree for diagnosing oral ulcerative lesions on the basis of their diagnostic features. Various general search engines and specialized databases including PubMed, PubMed Central, Medline Plus, EBSCO, Science Direct, Scopus, Embase, and authenticated textbooks were used to find relevant topics by means of MeSH keywords such as "oral ulcer," "stomatitis," and "mouth diseases." Thereafter, English-language articles published since 1983 to 2015 in both medical and dental journals including reviews, meta-analyses, original papers, and case reports were appraised. Upon compilation of the relevant data, oral ulcerative lesions were categorized into three major groups: acute, chronic, and recurrent ulcers and into five subgroups: solitary acute, multiple acute, solitary chronic, multiple chronic, and solitary/multiple recurrent, based on the number and duration of lesions. In total, 29 entities were organized in the form of a decision tree in order to help clinicians establish a logical diagnosis by stepwise progression.

By producing undistorted three-dimensional images of the area under examination, cone-beam computed tomography (CBCT) systems have met many of the limitations of conventional radiography. These systems produce images with small field of view at low radiation doses with adequate spatial resolution that are suitable for many applications in endodontics from diagnosis to treatment and follow-up. This review article comprehensively assembles all the data from literature regarding the potential applications of CBCT in endodontics.

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.

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.

Objectives: We aimed to design, implement and evaluate the efficacy of a comprehensive course on non-clinical competencies that dentists must possess for a successful dental practice., Materials and Methods: In this interventional before-after study an expert panel of five academic staff members and five general practitioners derived the topics for a course on successful dental practice, and aggregated them in the form of a two-day course. It was held for 46 randomly selected dentists in January 2010, at the School of Dentistry, Tehran University of Medical Sciences. The participants completed an anonymous questionnaire asking about their self-perceived need to receive training in each of the proposed topics and their self-assessed knowledge about each topic before and after attending the course., Results: Participants gave a higher priority to the necessity of training on "ergonomics and professional health" and communication skills in post-test compared to pre-test (P<0.05). The self-assessed knowledge of dentists improved significantly after attending the course in seven domains: ergonomics and occupational health, workplace design, documentation principles and IT applications in dentistry, national rules and regulations of dental practice, medical emergencies, dental ethics and communication skills (P<0.05). More than 70% of the participants were completely satisfied or satisfied with practical implication of the course, conformity of the contents with the title and course settings., Conclusion: The designed course seemed to be successful in revealing the need of participants for further education. Considering the high satisfaction rate of the attendants, this course can serve as a model for continuing education purposes.

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.

Purpose: This study aimed to assess the interdental bone level in premolar bitewing radiographs while retracting the cheeks., Methods: Seventy-two horizontal bone defects were created on dried mandibles and maxillae. The distance from the bone level to the cement-enamel junction of premolars was detected by a modified digital caliper (considered the gold standard). The reliability of all radiographs was assessed by intraclass correlation coefficient (ICC), and the validity was compared to the gold standard using the analysis of variance test. P-values less than 0.05 were considered statistically significant., Results: This study showed that the reliability of radiographs without a cheek simulator and with 0.16 second exposure time was significantly higher than that of the two other groups (ICC=0.96 compared to 0.93 and 0.88, respectively). The results from the radiographs without a cheek simulator and with 0.16 second exposure time were more similar to the gold standard measures than those of the two other groups, although the difference was not statistically significant., Conclusions: Retracting the buccal soft tissue plays an important role in increasing the accuracy of radiographs in detecting the interdental alveolar bone level and produces more accurate results than increasing the exposure time, although it does not have a significant role in reliability of results.

Introduction: Computed tomography (CT) and cone-beam CT (CBCT) are valuable diagnostic aids for many clinical applications. This study was designed to compare the gray scale value (GSV) and Hounsfield unit (HU) of selected dental materials and various hard tissues using CT or CBCT., Methods and Materials: Three samples of all test materials including amalgam (AM), composite resin (CR), glass ionomer (GI), zinc-oxide eugenol (ZOE), calcium-enriched mixture (CEM) cement, AH-26 root canal sealer (AH-26), gutta-percha (GP), Coltosol (Col), Dycal (DL), mineral trioxide aggregate (MTA), zinc phosphate (ZP), and polycarbonate cement (PC) were prepared and scanned together with samples of bone, dentin and enamel using two CBCT devices, Scanora 3D (S3D) and NewTom VGi (NTV) and a spiral CT (SCT) scanner (Somatom Emotion 16 multislice spiral CT);. Subsequently, the HU and GSV values were determined and evaluated. The data were analyzed by the Kruskal-Wallis and Mann-Whitney U tests. The level of significance was determined at 0.05., Results: There were significant differences among the three different scanners (P<0.05). The differences between HU/GSV values of 12 selected dental materials using NTV was significant (P<0.05) and for S3D and SCT was insignificant (P>0.05). All tested materials showed maximum values in S3D and SCT (3094 and 3071, respectively); however, bone and dentin showed low/medium values (P<0.05). In contrast, the tested materials and tissues showed a range of values in NTV (366 to15383; P<0.05)., Conclusion: Scanner system can influence the obtained HU/GSV of dental materials. NTV can discriminate various dental materials, in contrast to S3D/SCT scanners. NTV may be a more useful diagnostic aid for clinical practice.

Large skull defects as a result of craniectomies due to cerebral insults, trauma, or tumors create functional and aesthetic disturbances for the patient. Cranioplasty with implants in these cases are an alternative to autogenous bone transplantation. In our clinic, customized titanium or optima poly-ether-ether ketone (PEEK) implants are used to reconstruct craniectomy defects. To compare the two materials we investigated the structural changes of the implants fixed to a sintered polyamide skull model under mechanical stress in four simplified models. In a standard testing machine, the models were subjected to a load under a quasi-static loading rate of 1.925 mm/min. Fractures of the PEEK implants occurred at a force of 24.2 and 24.5 kN with a displacement of 8.4 and 8 mm. The titanium implants showed no deformation, but extensive damage was seen in the polyamide skull models. The highest pressures achieved were 45.8 and 50.9 kN. In a simplified model with quasi-static loading, both implants withstood forces that were higher than those capable of causing skull fractures. It seems that the mechanical properties of PEEK could provide better protection when used for cranioplasty in patients after craniectomy if reconstruction with autogenous bone is not possible.