Effect of different intracanal posts and exposure parameters on detection of vertical root fractures by cone-beam computed tomography.

This study evaluated the effect of different amperage values and voxel sizes of two CBCT scanners on VRF detection in the presence of different intracanal posts. After post-space preparation, VRFs were induced in half of the samples of 20 maxillary premolars. Five different intracanal posts were passively placed in each root canal. Samples were scanned using CS 9300 and Cranex3D with two different voxel sizes and amperage setting in each unit. The diagnostic sensitivity, specificity and accuracy were compared using the Mann-Whitney and Kruskal-Wallis tests (α = 0.05). Changes in amperage and voxel size did not affect the detection of VRFs (p ⟩ 0.05). The VRF detection accuracy was the highest in fibreglass and the lowest in nickel-chromium group. Changes in amperage and voxel size within assessed values do not seem to influence the detection of VRF whereas different intracanal post-materials have significant effect on VRF detection.

Efficacy of Metal Artifact Reduction Algorithm of Cone-Beam Computed Tomography for Detection of Fenestration and Dehiscence around Dental Implants.

BACKGROUND: Beam hardening and scattering artifacts from high-density objects such as dental implants adversely affect the image quality and subsequently the detection of fenestration or dehiscence around dental implants. OBJECTIVE: This study aimed to assess the efficacy of metal artifact reduction (MAR) algorithm of two cone-beam computed tomography (CBCT) systems for detection of peri-implant fenestration and dehiscence. MATERIAL AND METHODS: In this experimental study, thirty-six titanium implants were placed in bone blocks of bovine ribs. Fenestration and dehiscence were created in the buccal bone around implants. CBCT images were obtained using Cranex 3D and ProMax 3D CBCT systems with and without MAR algorithm. Two experienced radiologists observed the images. Data were analyzed using SPSS software. The Kappa coefficient of agreement, the area under the receiver operating characteristic (ROC) curve, sensitivity, specificity, and accuracy of different imaging modalities were calculated and analyzed. RESULTS: In both CBCT systems, the use of MAR algorithm decreased the area under the ROC curve and subsequently the diagnostic accuracy for the detection of fenestration and dehiscence. The sensitivity, specificity and accuracy of both CBCT systems were higher in absence of the MAR algorithm. The specificity of ProMax 3D for detection of fenestration was equal with/without the MAR algorithm. CONCLUSION: Although CBCT is suitable for detection of peri-implant defects, the application of the MAR algorithm does not enhance the detection of peri-implant fenestration and dehiscence.

Evaluation of the efficacy of the metal artifact reduction algorithm in the detection of a vertical root fracture in endodontically treated teeth in cone-beam computed tomography images: An in vitro study.

BACKGROUND: Three-dimensional (3D) cone-beam computed tomography (CBCT) scans play an important role in dental diagnostics and treatment planning, especially in detecting vertical root fractures (VRFs). However, artifacts caused by high-density dental materials can negatively affect the quality of CBCT images by decreasing contrast and masking structures. OBJECTIVES: The aim of this study was to assess the efficacy of artifact removal software in detecting VRFs in endodontically treated teeth on CBCT scans. MATERIAL AND METHODS: This study evaluated 70 endodontically treated single-rooted teeth. Half of the teeth were cracked by introducing a wedge into the canal and tapping gently with a hammer; the rest remained untouched as a control group. The teeth were then mounted in a bovine rib bone. Soft tissue was simulated using red dental wax. Cone-beam computed tomography scans were taken using the NewTom® 3G, ProMax® 3D and Cranex® 3D CBCT systems, and the MATLAB software was applied. The images were evaluated by 2 oral and maxillofacial radiologists, and the results were recorded in a checklist. The data was analyzed using the κ coefficient, McNemar's test and the receiver operating characteristic (ROC) curves. RESULTS: A significant inter-observer agreement was noted between the 2 observers in detecting VRFs using all CBCT systems. In all systems, the use of the MATLAB software improved the detection of VRFs, but the difference was not significant in the NewTom 3G (p = 0.119) and ProMax 3D (p = 0.455) systems. However, the difference was significant in the Cranex 3D system (p = 0.039). CONCLUSIONS: The MATLAB artifact removal software can enhance the detection of VRFs on CBCT scans to some extent.

Association between Marginal Bone Loss and Bone Quality at Dental Implant Sites Based on Evidence from Cone Beam Computed Tomography and Periapical Radiographs.

OBJECTIVE: The aim of this study was to assess bone quality in patient's preoperative cone beam computed tomography (CBCT) and their relation with marginal bone loss at implant placement sites over follow-up periods. MATERIALS AND METHODS: In this retrospective cross-sectional study, 100 implants were evaluated. The implants had been placed in the maxillary and mandibular edentulous areas. Bone quality at implant placement sites was measured on preoperative CBCTs and then classified by two observers according to Lekholm and Zarb classification. Marginal bone height was then measured on periapical radiographs obtained at baseline and then 6, 12, 18, 24, and 30 months' follow-up periods from a reference point (implant shoulder) to the bone-implant interface. The relation between bone quality and bone loss was assessed. ANOVA was used to compare mean difference among groups and Pearson correlation coefficient to assess the correlation between observers. All statistical analyses were performed at 0.05 significance level using Stata 11 software (StataCorp, College Station, TX, USA). RESULTS: Of 100 implants, 48 were placed in the maxilla and 52 in the mandible. There was no significant difference between bone quality and the mean bone loss at follow-up periods. Using Pearson's correlation coefficient, it was shown that with an increase in bone quality, marginal bone loss was decreased at follow-up periods. CONCLUSIONS: The results confirmed that during the follow-up periods, less bone loss was observed in implant areas with higher bone quality and CBCT is a reliable tool for assessing bone quality at implant placement sites and estimation of subsequent treatment prognosis.

Performance of Cone Beam Computed Tomography Systems in Visualizing the Cortical Plate in 3D Image Reconstruction: An In Vitro Study.

INTRODUCTION: Cortical bone is an important anatomical structure and its thickness needs to be determined prior to many dental procedures to ensure treatment success. Imaging modalities are necessarily used in dentistry for treatment planning and dental procedures. Three-dimensional image reconstruction not only provides visual information but also enables accurate measurement of anatomical structures; thus, it is necessarily required for maxillofacial examination and in case of skeletal problems in this region. AIMS: This study aimed to assess the ability of three Cone Beam Computed Tomography (CBCT) systems including Cranex 3D, NewTom 3G and 3D Promax for Three-Dimensional (3D) image reconstruction of the cortical plate with variable thicknesses. METHODS: Depending on the cortical bone thickness, samples were evaluated in three groups of ≤ 0. 5 mm, 0.6 -1 mm and 1.1-1.5 mm cortical bone thickness. The CBCT scans were obtained from each sample using three systems, their respective FOVs, and 3D scans were reconstructed using their software programs. Two observers viewed the images twice with a two-week interval. The ability of each system in the 3D reconstruction of different thicknesses of cortical bone was determined based on its visualization on the scans. The data were analyzed using SPSS and Kappa test. RESULTS: The three systems showed the greatest difference in the 3D reconstruction of cortical bone with < 0.5 mm thickness. Cranex 3D with 4×6 cm2 FOV had the highest and 3D Promax with 8×8 cm2 FOV had the lowest efficacy for 3D reconstruction of cortical bone. Cranex 3D with 4×6 cm2 and 6×8 cm2 FOVs and NewTom 3G with 5×5 cm2 and 8×5 cm2 FOVs showed significantly higher efficacy for 3D reconstruction of cortical bone with 0.6-1mm thickness while 3D Promax followed by NewTom 3G with 8×8 cm2 FOV had the lowest efficacy for this purpose. CONCLUSION: Most CBCT systems have high efficacy for 3D image reconstruction of cortical bone with thicknesses over 1 mm while they have poor efficacy for image reconstruction of cortical bone with less than 0.5 mm thickness. Thus, for accurate visualization of anatomical structures on CBCT scans, systems with smaller FOVs and consequently smaller voxel size are preferred.

Diagnostic Accuracy of Three Cone Beam Computed Tomography Systems and Periapical Radiography for Detection of Fenestration Around Dental Implants.

CONTEXT: Early detection of peri-implant bone defects is highly important to prevent further bone loss and implant failure. AIMS: This study aimed to assess the diagnostic accuracy of three cone-beam computed tomography (CBCT) systems and periapical radiography for detection of fenestration around dental implants. METHODS: Thirty-one titanium implants were placed in the bovine ribs, in which peri-implant fenestration were simulated. Using a round fissure bur, fenestration defects were created in the apical-third region of implants. CBCT and PA radiographs were obtained before and after creating the defects. The results were analyzed using Chi-square test; kappa coefficient; Cochran's Q-test; McNemar's test; and sensitivity, specificity, positive predictive value, and negative predictive value; and receiver operating characteristic curve. RESULTS: A significant agreement was noted between the two observers in the detection of defect-free samples in all imaging systems (P < 0.05). In detection of samples with defects, a significant agreement was observed between the two observers in use of Cranex three-dimensional and NewTom 3G systems (P < 0.05), but the agreement was not significant for detection of defects in use of Promax 3D (P > 0.05). The results showed no significant difference among the four imaging systems in detection of defect-free samples while the difference was significant among the four groups for detection of defects (P < 0.05). NewTom had the highest sensitivity (75.81%) and specificity (100%) for detection of fenestration. CONCLUSIONS: Within the limitations of CBCT systems different kVp used by different systems, artifacts and noises that influences image quality, difference in diagnostic value of different CBCT systems is due to the differences in type of detector and voxel size. In terms of the type of detector, our results showed that NewTom 3G, which has a higher (kVP) than other systems and the highest accuracy for detection of fenestration.

Iatrogenic Errors during Root Canal Instrumentation Performed by Dental Students.

INTRODUCTION: The present study was set to investigate the training quality and its association with the quality of root canal therapy performed by fifth year dentistry students. METHODS AND MATERIALS: A total number of 432 records of endodontic treatment performed by fifth year dentistry students were qualified to be further investigated. Radiographs were assessed by two independent endodontists. Apical transportation, apical perforation, gouging, ledge formation, and the quality of temporary restoration were error types investigated in the present study. RESULTS: the prevalence of apical transportation, ledge formation, and apical perforation errors were significantly higher in molars in comparison with other types of teeth. The most prevalent type of error was the apical transportation, which was significantly higher in mandibular teeth. There was no significant differences among teeth in terms of other types of errors. CONCLUSION: The quality of training provided for dentistry students should be improved and endodontic curriculum should be modified.

Diagnostic accuracy of cone-beam computed tomography scans with high- and low-resolution modes for the detection of root perforations.

PURPOSE: This study compared the diagnostic accuracy of cone-beam computed tomography (CBCT) scans obtained with 2 CBCT systems with high- and low-resolution modes for the detection of root perforations in endodontically treated mandibular molars. MATERIALS AND METHODS: The root canals of 72 mandibular molars were cleaned and shaped. Perforations measuring 0.2, 0.3, and 0.4 mm in diameter were created at the furcation area of 48 roots, simulating strip perforations, or on the external surfaces of 48 roots, simulating root perforations. Forty-eight roots remained intact (control group). The roots were filled using gutta-percha (Gapadent, Tianjin, China) and AH26 sealer (Dentsply Maillefer, Ballaigues, Switzerland). The CBCT scans were obtained using the NewTom 3G (QR srl, Verona, Italy) and Cranex 3D (Soredex, Helsinki, Finland) CBCT systems in high- and low-resolution modes, and were evaluated by 2 observers. The chi-square test was used to assess the nominal variables. RESULTS: In strip perforations, the accuracies of low- and high-resolution modes were 75% and 83% for NewTom 3G and 67% and 69% for Cranex 3D. In root perforations, the accuracies of low- and high-resolution modes were 79% and 83% for NewTom 3G and was 56% and 73% for Cranex 3D. CONCLUSION: The accuracy of the 2 CBCT systems was different for the detection of strip and root perforations. The Cranex 3D had non-significantly higher accuracy than the NewTom 3G. In both scanners, the high-resolution mode yielded significantly higher accuracy than the low-resolution mode. The diagnostic accuracy of CBCT scans was not affected by the perforation diameter.

Radiographic Quality of Root Canal Obturation Performed By Fifth Year Students of Hamadan Dental School.

INTRODUCTION: The aim of this study was to assess the radiographic technical quality of root canal therapy performed by fifth year students of Dental School of Hamadan University of Medical Sciences from 2015 to 2016. METHODS AND MATERIALS: Four hundred and seventy records of root canal therapies were evaluated. Records with graphies taken as initial, master apical file (MAF), master apical cone (MAC) and final radiographs were included in the study and records of patient younger than 16 years and older than 68 years were excluded from further investigations. Lastly, 432 teeth were selected. Obturation length, canal tapering, quality and density of filling material were the variables investigated in the present study. Two independent investigators examined the radiographies using a magnifying lens (×2) and x-ray viewer. Data were analyzed using chi-square test. RESULTS: The technical quality of root filling performed by undergraduate dental students was classified as acceptable in 10.4% of cases. Moreover, 70.8% of teeth had adequate filling, 17.1% were underfilled and 12% were overfilled. The three groups were significantly different in terms of working length and taper quality. One hundred ninety four (44.9%) records had adequate taper and 109 (25%) records had adequate density. There was a significant association between teeth location and the length of obturation so that the probability of a successful treatment was higher in maxillary teeth. Furthermore, the rate of a proper length of obturation was higher among incisors than that of premolars and molars. CONCLUSION: The technical quality of root canal therapy performed by dental students in Hamadan University of medical sciences is not as acceptable as it should be. One of the most important factors in this regard is a high student/professor ratio.

Evaluation of the Effect of Light and Scanning Time Delay on The Image Quality of Intra Oral Photostimulable Phosphor Plates.

BACKGROUND: Nowadays, digital radiography is widely used in dental practice. One of the most common types is Photo Stimulated Phosphor Plate (PSP). OBJECTIVE: The aims of this experimental study were to evaluate the impacts of different combinations of storage conditions and varying delays in reading of digital images captured using PSPs. METHODS: Standardized images of a step wedges were obtained using PSPs from the Digora digital systems. Plates were exposed and immediately scanned to produce the baseline gold standard. The plates were re-exposed and stored in four different storage conditions: white light, yellow light, natural light environment and dark room, then scanned after 10 and 30 minutes and 4 and 8 hours. Objective analysis was conducted by density measurements and the data were analyzed statistically using GEE test. Subjective analysis was performed by two oral and maxillofacial radiologists and the results were analyzed using McNemar's test. RESULTS: The results from GEE analysis show that in the natural light environment, the densities in 10 minutes did not differ from the baseline. The mean densities decreased significantly during the time in all environments. The mean densities in step 2 for the dark room environment decreased with a slighter slope in comparison to yellow environment significantly. CONCLUSION: PSP images showed significant decrease in the density in plates scanned for 10 minutes or longer after exposure which may not be detected clinically. The yellow light environment had a different impact on the quality of PSP images. The spatial resolution did not change significantly with time.

Effect of Time Lapse on the Diagnostic Accuracy of Cone Beam Computed Tomography for Detection of Vertical Root Fractures.

Accurate and early diagnosis of vertical root fractures (VRFs) is imperative to prevent extensive bone loss and unnecessary endodontic and prosthodontic treatments. The aim of this study was to assess the effect of time lapse on the diagnostic accuracy of cone beam computed tomography (CBCT) for VRFs in endodontically treated dog's teeth. Forty-eight incisors and premolars of three adult male dogs underwent root canal therapy. The teeth were assigned to two groups: VRFs were artificially induced in the first group (n=24) while the teeth in the second group remained intact (n=24). The CBCT scans were obtained by NewTom 3G unit immediately after inducing VRFs and after one, two, three, four, eight, 12 and 16 weeks. Three oral and maxillofacial radiologists blinded to the date of radiographs assessed the presence/absence of VRFs on CBCT scans. The sensitivity, specificity and accuracy values were calculated and data were analyzed using SPSS v.16 software and ANOVA. The total accuracy of detection of VRFs immediately after surgery, one, two, three, four, eight, 12 and 16 weeks was 67.3%, 68.7%, 66.6%, 64.6%, 64.5%, 69.4%, 68.7%, 68% respectively. The effect of time lapse on detection of VRFs was not significant (p>0.05). Overall sensitivity, specificity and accuracy of CBCT for detection of VRFs were 74.3%, 62.2%, 67.2% respectively. Cone beam computed tomography is a valuable tool for detection of VRFs. Time lapse (four months) had no effect on detection of VRFs on CBCT scans.

Effect of Time Lapse on the Diagnostic Accuracy of Cone Beam Computed Tomography for Detection of Vertical Root Fractures

Abstract Accurate and early diagnosis of vertical root fractures (VRFs) is imperative to prevent extensive bone loss and unnecessary endodontic and prosthodontic treatments. The aim of this study was to assess the effect of time lapse on the diagnostic accuracy of cone beam computed tomography (CBCT) for VRFs in endodontically treated dog's teeth. Forty-eight incisors and premolars of three adult male dogs underwent root canal therapy. The teeth were assigned to two groups: VRFs were artificially induced in the first group (n=24) while the teeth in the second group remained intact (n=24). The CBCT scans were obtained by NewTom 3G unit immediately after inducing VRFs and after one, two, three, four, eight, 12 and 16 weeks. Three oral and maxillofacial radiologists blinded to the date of radiographs assessed the presence/absence of VRFs on CBCT scans. The sensitivity, specificity and accuracy values were calculated and data were analyzed using SPSS v.16 software and ANOVA. The total accuracy of detection of VRFs immediately after surgery, one, two, three, four, eight, 12 and 16 weeks was 67.3%, 68.7%, 66.6%, 64.6%, 64.5%, 69.4%, 68.7%, 68% respectively. The effect of time lapse on detection of VRFs was not significant (p>0.05). Overall sensitivity, specificity and accuracy of CBCT for detection of VRFs were 74.3%, 62.2%, 67.2% respectively. Cone beam computed tomography is a valuable tool for detection of VRFs. Time lapse (four months) had no effect on detection of VRFs on CBCT scans.

Resumo Um diagnostico correto e a tempo das fraturas radiculares verticais (FRVs) é essencial para prevenir extensa perda óssea, tratamentos endodônticos e próteses desnecessárias. O objetivo do presente estudo foi avaliar o efeito do tempo decorrido sobre a acurácia diagnóstica da tomografia computadorizada de feixe cônico (TCFC) para detecção de FRVs em dentes de cães tratados endodonticamente. Quarenta e oito dentes incisivos e premolares obtidos de três cães machos adultos tiveram os seus canais tratados. Os dentes foram divididos em dois grupos: no primeiro grupo (n=24) foram artificialmente induzidas FRVs, enquanto no segundo grupo (n=24) os dentes permaneceram intactos. As imagens de TCFC foram obtidas pela unidade NewTom 3G imediatamente após a cirurgia de indução das FRVs e uma, duas, três, quarto, oito, 12 e 16 semanas depois. Três radiologistas cegos para as datas das imagens avaliaram a presença/ausência de FRVs nas imagens de TCFC. Foram calculados os valores da sensibilidade, especificidade e acurácia, sendo os dados analisados por ANOVA e pelo programa SPSS v.16. As acurácias totais de detecção das FRVs imediatamente após sua indução e uma, duas, três, quarto, oito, 12 e 16 semanas depois foram respectivamente de 67,3%, 68,7%, 66,6%, 64,6%, 64,5%, 69,4%, 68,7% e 68%. O efeito do tempo decorrido foi sem significado estatístico (p>0,05). A TCFC produziu valores gerais de sensibilidade, especificidade e acurácia de 74,3%, 62,2% e 67.2%, respectivamente. A tomografia computadorizada de feixe cônico é uma ferramenta valiosa para detecção de FRVs. O tempo decorrido (quatro meses) não teve influência sobre a detecção de FRVs nas imagens de TCFC.

Detection of root perforations using conventional and digital intraoral radiography, multidetector computed tomography and cone beam computed tomography.

OBJECTIVES: This study aimed to compare the accuracy of conventional intraoral (CI) radiography, photostimulable phosphor (PSP) radiography, cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) for detection of strip and root perforations in endodontically treated teeth. MATERIALS AND METHODS: Mesial and distal roots of 72 recently extracted molar were endodontically prepared. Perforations were created in 0.2, 0.3, or 0.4 mm diameter around the furcation of 48 roots (strip perforation) and at the external surface of 48 roots (root perforation); 48 roots were not perforated (control group). After root obturation, intraoral radiography, CBCT and MDCT were taken. Discontinuity in the root structure was interpreted as perforation. Two observers examined the images. Data were analyzed using Stata software and Chi-square test. RESULTS: The sensitivity and specificity of CI, PSP, CBCT and MDCT in detection of strip perforations were 81.25% and 93.75%, 85.42% and 91.67%, 97.92% and 85.42%, and 72.92% and 87.50%, respectively. For diagnosis of root perforation, the sensitivity and specificity were 87.50% and 93.75%, 89.58% and 91.67%, 97.92% and 85.42%, and 81.25% and 87.50%, respectively. For detection of strip perforation, the difference between CBCT and all other methods including CI, PSP and MDCT was significant (p < 0.05). For detection of root perforation, only the difference between CBCT and MDCT was significant, and for all the other methods no statistically significant difference was observed. CONCLUSIONS: If it is not possible to diagnose the root perforations by periapical radiographs, CBCT is the best radiographic technique while MDCT is not recommended.

CBCT findings of periapical cemento-osseous dysplasia: A case report.

Periapical cemento-osseous dysplasia (PCOD) is a subtype of cemento-osseous dysplasia that usually occurs in middle-aged black women. This report described a case of a 45-year-old Iranian woman who was diagnosed with PCOD on the basis of cone beam computed tomographic (CBCT) findings. CBCT enabled detailed visualization of the bone changes. This report described the special radiographic characteristics of PCOD, including discontinuity of the lingual cortex on the CBCT sectional and three-dimensional images.

Comparison of cone-beam computed tomography with intraoral photostimulable phosphor imaging plate for diagnosis of endodontic complications: a simulation study.

OBJECTIVES: The objective of this study was to compare the sensitivity and reliability of cone-beam computed tomography (CBCT) and intraoral photostimulable phosphor (PSP) imaging plate for diagnosis of endodontic complications. STUDY DESIGN: Seventy-two human mandibular teeth were used, including 24 incisors/canines, 24 premolars, and 24 molars. Three images were taken from each group of teeth with intraoral PSP, CBCT-NewTom, and CBCT-ProMax. RESULTS: The sensitivity of PSP, CBCT-NewTom, and CBCT-ProMax was 76.39%, 80.56%, and 94.44% for detecting cast post deviation; 98.61%, 100%, and 100% for external root resorption; 86.11%, 31.94%, and 36.11% for fractured file; and 66.67%, 90.28%, and 86.11% for lateral root perforation respectively. The intertechnique reliability (kappa statistics) was 58.4% for the 2 CBCT techniques, 20.1% and 18.8% for CBCT-NewTom and CBCT-ProMax versus PSP respectively. CONCLUSIONS: Given strengths and weaknesses of the techniques as well as the cost, CBCT is recommended as a complementary but not routinely used diagnostic method for endodontic complications not usually detected by conventional methods.

Effect of object location on the density measurement in cone-beam computed tomography versus multislice computed tomography.

BACKGROUND: Bone density measurement in a radiographic view is a valuable method for evaluating the density of bone quality before performing some dental procedures such as, dental implant placements. It seems that Cone-Beam Computed Tomography (CBCT) can be used as a diagnostic tool for evaluating the density of the bone, prior to any treatment, as the reported radiation dose in this method is minimal. The aim of this study is to investigate the effect of object location on the density measurement in CBCT versus Multislice computed tomography (CT). MATERIALS AND METHODS: In an experimental study, three samples with similar dimensions, but different compositions, different densities (Polyethylene, Polyamide, Polyvinyl Chloride), and three bone pieces of different parts of the mandibular bone were imaged in three different positions by CBCT and Multislice CT sets. The average density value was computed for each sample in each position. Then the data obtained from each CBCT was converted to a Hounsfield unit and evaluated using a single variable T analysis. A P value <0.05 was considered to be significant. RESULTS: The density in a Multislice CT is stable in the form of a Hounsfield Number, but this density is variable in the images acquired through CBCT, and the change in the position results in significant changes in the density. In this study, a statistically significant difference (P value = 0.000) has been observed for the position of the sample and its density in CBCT in comparison to Multislice CT. CONCLUSIONS: Density values in CBCT are not real because they are affected by the position of the object in the machine.