Genotoxicity and Micronucleus Formation as a Result of Panoramic Radiography in Epithelial Cells of the Buccal Mucosa: A Cross-sectional Study in Adults.

OBJECTIVES: To determine the genetic effects of panoramic radiography on the epithelial cells of the buccal mucosa by examining the micronucleus formation in these cells. MATERIALS AND METHODS: In this cross-sectional study, exfoliative cytology samples were prepared from the buccal mucosa of 36 patients immediately before and 10 days after panoramic radiography. The samples were prepared using liquid-based cytology with Papanicolaou staining. The slides were simultaneously evaluated by two expert pathologists and the ratio of the number of cells with micronuclei to the total number of cells on the slide was reported as a percentage. Data analysis was done using paired-samples T test, Pearson's correlation coefficient, and covariance analysis (α = 0.05). RESULTS: The study sample consisted of 24 (66.67%) males and 12 females (33.33%) with a mean (SD) age of 27.36 (8.19) years. The frequency of cells with micronucleus before and after panoramic radiography was not statistically different (p = 0.468). Additionally, the frequency of micronucleated cells was not correlated with age (p = 0.737) and sex (p = 0.211). CONCLUSION: Panoramic exposure slightly increased the frequency of cells with micronucleus in epithelial cells of the buccal mucosa. However, this increase was not statistically significant.

Evaluation of Using Panoramic Radiography and Ultrasonography for Diagnosing Carotid Artery Calcifications.

Background: The aim of this study was to determine the reliability of panoramic radiograph (PR) as a screening tool for the detection of calcified carotid atheroma (CCA) in comparison with Doppler ultrasonography (DU) examination. Materials and Methods: In this study, DU was performed for 52 patients who had carotid calcification or other differential diagnoses of carotid calcification on PR routine screening. The data relating to the presence or absence of calcified atheroma in DU and PR were evaluated using SPSS software. Results: In the 52 stated patients, CCA of 9 (18%) patients was diagnosed in the PR. Significant differences in CCA between the two sexes were not found. Also, considerable differences between the left and right sides (P = 0/906) were not found. Moreover, the positive cases who are diagnosed using ultrasonography and PR were 2.25% and 6.5%, respectively. Conclusion: PR method is not a good choice for the primary diagnosis method for the carotid artery calcifications due to its less positive diagnosing ratio compared to DU.

Impact of Using Standard and High-Resolution Exposure Modalities of Cone-Beam Computed Tomography (CBCT) System for Dental Implants Dimension Measurements.

Background: This study aimed to analyze the effects of standard and high-resolution exposures on the diagnostic accuracy of CBCT in the evaluation of dental implant dimensions. Materials and Methods: A descriptive-analytical study was carried out on 40 dry human mandibles with appropriate ridge quality based on panoramic radiography. CBCT (Soredex, Cranex 3D, Finland) with a large field of view (FOV) and CMOS flat panel detector were used. CBCT with standard and a high resolution was performed in each mandible. Axial images, reconstructed by OnDemand 3D software, were processed to prepare cross-sectional images from the areas marked by gutta-percha, and then measured by a ruler with an accuracy of 0.01 millimeter in the computer. Measurements were recorded by two observers and the obtained data were compared with the real ones. Results: The results showed suitable repeatability in radiologic measurements (r = 0.971), which is indicative of the high reliability of intraobserver measurement. The measurement of width with high-resolution exposure indicated a significant difference with the real condition (P < 0.001); however, this difference was not significant in the case of standard resolution (P > 0.05). Measurement of height with high resolution showed a significant difference with the real condition in the right mandible (P = 0.04) and left mandible (P = 0.05); however, this difference was not significant in standard resolution (P > 0.05). Conclusion: Based on our findings, the standard CBCT resolution modality is suggested for dental implant images due to its higher accuracy than high-resolution methods for diagnosing the implant dimensions.

Comparative Evaluation of the Accuracy of Gingival Thickness Measurement by Clinical Evaluation and Intraoral Ultrasonography.

This study aimed to investigate the accuracy of gingival thickness measurement by two methods of clinical evaluation and intraoral ultrasonography. The gingival thickness was measured in the midbuccal area of the right maxillary lateral incisor and first molar teeth in 30 individuals. For clinical measurement, a #15 K-file with rubber stops was vertically inserted 2 mm apical to the gingival margin and the length of the file in the tissue was measured using a digital caliper. Ultrasonographic measurement was performed using an intraoral probe on the gingival surface in the midbuccal area, at the entry point of the file. Statistical analysis was performed by paired t-test, correlation coefficient, and receiver operating characteristic (ROC) curve (α = 0.05). In the anterior region, the mean gingival thicknesses using ultrasonography (1.517 ± 0.293 mm) and clinical evaluation (1.610 ± 0.272 mm) were not significantly different (p = 0.434). In the posterior region, the mean gingival thicknesses were significantly different between ultrasonography (1.372 ± 0.442 mm) and clinical evaluation (1.626 ± 0.310 mm) (p = 0.006). The area under ROC curve values for ultrasonographic measurements in the anterior and posterior regions were 0.681 and 0.597, respectively. The use of ultrasonography with an intraoral probe has acceptable accuracy for the determination of gingival thickness, especially for the anterior regions.

Evaluation of histogram equalization and contrast limited adaptive histogram equalization effect on image quality and fractal dimensions of digital periapical radiographs.

OBJECTIVES: This study aims to evaluate the effects of histogram equalization (HE) and contrast limited adaptive histogram equalization (CLAHE) on periapical images and fractal dimensions in the periapical region. METHODS: In this cross-sectional study, digital periapical images were selected from the archive of Dentistry School of Isfahan University of Medical Sciences. The radiographs were taken from mandibular and maxillary anterior single root teeth with healthy root and periodontium. After applying HE and CLAHE algorithms to images, two radiologists evaluated the quality of apex detection from using a 5-point Likert scale (from 5 for very good image quality to 1 for very bad image quality). Afterward, all the images were imported to the ImageJ application, and the region of interest (ROI) was specified as the region between the two central incisors. The fractal box-counting method was used to determine fractal dimensions (FD) values. Nonparametric Wilcoxon-Friedman test, Intraclass Correlation Coefficient test, T-test, and Pair T-test were performed as statistical analysis (α = 0.05). RESULTS: Fifty-three radiographs were analyzed and the image quality assessments were significantly different between raw images and images after performing HE, CLAHE (p value < 0.001), and using CLAHE algorithm significantly increases image quality assessments more than HE (p value = 0.009). There was a significant difference in FD values for images after applying CLAHE and HE compared to raw images (p value < 0.001), and HE decreased the FD value significantly more than CLAHE (p value = 0.019). CONCLUSIONS: Employing CLAHE and HE algorithm via OpenCV python library improves the periapical image quality, which is more significant using the CLAHE algorithm. Moreover, applying CLAHE and HE reduces trabecular bone structure detection and FD values in periapical images, especially in HE.

Cone-beam computed tomographic comparison of chin symphysis bone particles and allograft versus iliac crest bone graft alone for reconstruction of alveolar bone defects in cleft patients.

Objectives: The aim of this study was to compare morbidities and duration of surgery, as well as bone formation in alveolar defects reconstructed with symphysis bone combined with allograft and iliac crest bone graft in patients with cleft palate. Patients and. Methods: This randomized clinical trial was performed with 22 patients with unilateral alveolar cleft with a follow-up period of 12 months. In 12 patients, alveolar defects were reconstructed with chin bone graft plus allograft (Group A), while for the other 10 patients, iliac bone crest was used as donor site (Group B). Duration of surgery as well as occurrence of morbidities and complications were recorded. In addition, cone-beam computed tomographic (CBCT) scans were performed before surgery and 12 months after surgical procedures in order to compare bone formation between the two groups. Results: Postoperative CBCT demonstrated a mean bone fill percentage of 76.9% of the alveolar defect in Group A, compared with 77.0% in Group B. Paresthesia in the lower lip or chin did not occur in any patients of Group A. The mean duration of the surgical process was significantly shorter for Group A (40 minutes vs 76 minutes, P<0.001). In addition, patients in Group A regained normal gait faster than patients in Group B (1 day vs 9.5 days). Conclusion: Mandibular symphysis bone graft in combination with allograft results in favorable outcomes in patients with unilateral alveolar clefts.

Comparison of antimicrobial and wound-healing effects of silver nanoparticle and chlorhexidine mouthwashes: an in vivo study in rabbits.

The objective is to formulate a silver nanoparticle mouthwash and then evaluate its antimicrobial and wound-healing effects in rabbit animal models. Microbial samples were collected from the oral cavity of 60 rabbits. Thereafter, standardized wounds were created in the lateral border of the tongue on the right side for all rabbits. After surgery, digital photographs were obtained from the wounds with standardized settings. To characterize the silver nanoparticles used in the synthetic mouthwash, transmission electron microscopy (TEM) and digital light scattering analysis were used. The animal models were then randomly divided into 4 groups: group 1 received 9.80 wt% silver nanoparticle mouthwash; group 2 received all the ingredients of the formulated mouthwash except for silver nanoparticles; group 3 received chlorhexidine 2.0% mouthwash; and the negative control group did not receive any postoperative mouthwash. Microbial samples were collected from oral cavity of the rabbits each day for four postoperative days. Colony-forming unit (CFU) counts were compared post-operatively with the pre-operative counts. In addition, standardized digital photographs were taken each day from the wounds and the area of the wounds was compared in postoperative and pre-operative images. Data were statistically analyzed using one-way ANOVA and repeated measures variance analysis (α = 0.05). TEM revealed spherical morphology of silver nanoparticles and digital light scattering showed an average size of 5 nm and optimal distribution of the nanoparticles. CFU count significantly decreased in groups 1 and 3 (P < 0.001), while it significantly increased in groups 2 and 4 (P < 0.001). Moreover, a significant difference was observed between the experimental groups (P < 0.001). In addition, wound area decreased significantly in all groups (P < 0.001). However, the difference between wound areas in the groups was not significant, except for the 4th postoperative day (P < 0.001). However, the antibacterial effects and the wound-healing characteristics of the synthetic silver nanoparticle and chlorhexidine mouthwashes were not significantly different (P > 0.05). Silver nanoparticle mouthwash possesses favorable antibacterial and wound-healing effects. The formulated 9.80 wt% silver nanoparticle mouthwash with a particle size of 5 nm can be a promising alternative for application after oral surgical procedures.

Anatomy assessment of permanent mandibular premolar teeth in a selected Iranian population using cone-beam computed tomography.

BACKGROUND: Appropriate cleaning and shaping and three-dimensional obturation of the root canal system lead to a successful endodontic treatment. To achieve this, complete knowledge of the internal anatomy of root canals is necessary. Therefore, this study evaluated the number and shape of mandibular premolar roots and canals and classified their Vertucci classification using cone-beam computed tomography (CBCT) images of an Iranian sample population. MATERIALS AND METHODS: This in vivo study was performed on CBCT images of patients aged 20-70 years who had attended a dental radiology center in Isfahan. CBCT images were examined in coronal, sagittal, and especially axial dimensions. Descriptive statistics were calculated. Groups were compared using the Chi-square of the Statistical Package for the Social Sciences. The level of significance was predetermined as 0.05. RESULTS: In both first and second premolars, the most common classes were Type I followed by Type V. The Chi-square did not show significant differences between males and females in terms of Vertucci classes in the first (P = 0.305) or second premolar (P = 0.315). CONCLUSION: Since a thorough knowledge of root canal anatomy is necessary for successful root canal treatment and almost one out of ten mandibular premolars has additional canal in their root canal system, accurate evaluating of preoperative radiographs, taking CBCT images if necessary, and probing the root canal system with fine and precurved files should be done to negotiate the entire canal system.

Evaluation of the CBCT imaging accuracy in the volumetric assessment of unilateral alveolar cleft.

INTRODUCTION: Appropriate radiographic evaluation is a fundamental step for determining the topography of the defect before the surgical intervention for alveolar bone grafting. Evaluation of cleft volume by CBCT has been done in dry skull samples in previous studies and it was recommended as an effective tool in the volumetric evaluation of the bone defect prior to the surgery. The purpose of this study was to evaluate the accuracy of preoperative clinical use of CBCT2 imaging in determining the alveolar cleft volume. MATERIAL AND METHODS: We performed a clinical study. 20 patients with unilateral alveolar cleft underwent preoperative radiographic evaluation using CBCT scan. Volumetric measurement was performed by an oral and maxillofacial radiologist using 0.5, 1, and 2 mm slices and an oral and maxillofacial surgeon using 2 mm slices. After the closure of the nasal floor and palatal mucosa, the alveolar defect was clinically measured with putty impression material. Descriptive and bivariate statistics were computed and the p-value was set at 0.05. RESULTS: This study showed that there is a statistically significant difference between CBCT-estimated and clinical volumes of the alveolar cleft (paired T-test, p-value < 0.05). CONCLUSION: Considering the significant difference between clinical and CBCT-estimated volumes of the alveolar cleft, CBCT imaging is not considered an accurate tool for pre-operative volumetric assessment of the alveolar cleft.

Evaluation of Relationship between Exposure Parameters and Maxillofacial Bone Quality with Salivary Glands Absorbed Dose in Cone Beam Computed Tomography Imaging.

AIM: The purpose of this study was to evaluate the protective effect of jaw bone on the dose of salivary glands and its relationship with radiation conditions. MATERIALS AND METHODS: In this cross-sectional study, seven dried human skulls were used. In each mandible, six dosimeters were placed in six salivary gland regions numbered in visible light absorbent envelopes. Cone beam computed tomography (CBCT) images were taken from each mandible with a constant kV of 90 and mA varied from 6, 8, and 10. The absorbed dose was calculated using SOLAR 2A. The bone quality of each of the six areas was obtained using densitometry tool in On Demand software. Finally, the results were analyzed using Statistical Package for the Social Sciences (SPSS) software version 23 with covariance and Tukey tests (α = 0.05). RESULTS: The results of covariance analysis and Tukey test indicated that the sublingual salivary gland had the highest absorption dose. Meanwhile, the results of the analysis showed that the absorption rate of the glands increased by increasing the radiation conditions from 6 to 8 and increasing from 8 to 10 mA (p < 0.001). The results of Pearson analysis showed an inverse relationship between absorbed dose and bone quality (r = -0.327) (p < 0.001). CONCLUSION: The results of this study showed that the absorption rate of salivary glands will increase with increasing radiation conditions, while increasing the quality of mandibular bone, the absorption dose will decrease. CLINICAL SIGNIFICANCE: The clinical significance is to reduce patient's absorbed dose in order to decrease the risk of mutation and cancer formation.

Comparative evaluation of root canal morphology of mandibular premolars using clearing and cone beam computed tomography.

BACKGROUND: Different techniques are used to evaluate the anatomy of root canal system. The present study was aimed to evaluate the root canal morphology of mandibular premolars using clearing and cone beam computed tomography (CBCT) techniques. MATERIALS AND METHODS: A total of 182 mandibular first and second premolars were evaluated in vitro using 100 µm CBCT cross sections. The root canal morphology of the teeth was determined based on Vertucci classification in relation to the prevalence of C-shaped canals, lateral canals, and furcation location. Having removed the pulp tissue with NaOCl solution and staining the root canals with India ink, the samples were decalcified with 5% nitric acid and dehydrated with isopropyl alcohol. Finally, the samples were cleared with methyl salicylate. Data were analyzed by SPSS 16 software using McNamara, t-test, and Kappa coefficient. RESULTS: After Type I, the most frequent morphologies in both first and second premolars were Type V followed by Type IV. The prevalence rates of C-shaped morphology in first premolars using clearing and CBCT were 4.4% and 6.6%, respectively. However, no C-shaped morphology was found in second premolars. The maximum and minimum levels of agreement between the two techniques were observed in Type IV and Type V root canal morphologies, respectively. Extra root canals were identified in 25% and 13% of the first and second premolars, respectively. CONCLUSION: CBCT showed a higher accuracy in determining C-shaped root canal morphology than the clearing technique. It also showed the least accuracy in diagnosing lateral root canals.

Root Morphology and Canal Configuration of First and Second Maxillary Molars in a Selected Iranian Population: A Cone-Beam Computed Tomography Evaluation.

INTRODUCTION: The aim of this investigation was to evaluate root canal morphology of maxillary first and second molars and also to assess the prevalence and morphology of the second mesiobuccal canal (MB2) in these teeth, using cone-beam computed tomography (CBCT). METHODS AND MATERIALS: In this cross-sectional study, the total of 470 CBCT images from the archive of Radiology Department of Isfahan University of Medical Sciences (IUMS), Iran, was evaluated and 295 images were selected. The number of roots, and canal configuration were determined based on Vertucci's classification system. The data was analyzed using SPSS 20, and P-values less than 0.05 were considered significant. RESULTS: A total of 295 images from 295 patients (165 females and 130 males), including 389 maxillary first (197 right and 192 left) and 460 maxillary second (235 right and 225 left) molars were evaluated. The prevalence of MB2 canals were 70.2% and 43.4% in the maxillary first and second molars, respectively. The most common type of Vertucci's classification was type II (53.1%), followed by type I. CONCLUSION: The second mesiobuccal canal was present in almost two thirds of first and less than half of second molars. The morphology and canal configuration of a maxillary molar can almost predict the morphology of contralateral molar. However, it does not relate to the ipsilateral molar.

Chin Symphysis Bone, Allograft, and Platelet-Rich Fibrin: Is the Combination Effective in Repair of Alveolar Cleft?

PURPOSE: Secondary grafting of alveolar defects with iliac crest bone is a common treatment method in cleft patients. The aim of this study was to evaluate the effectiveness of the combination of symphysis bone, allograft, and platelet-rich fibrin in regeneration of alveolar defects compared with iliac bone graft. MATERIALS AND METHODS: In this randomized clinical trial, patients with unilateral alveolar defects were divided randomly into two categories. Group A comprised patients in whom the combination of chin symphysis bone plus allogeneic bone material plus leukocyte- and platelet-rich fibrin was considered for treatment. Group B comprised patients in whom iliac bone graft was considered. Cone beam computed tomography before treatment and 1 year postoperatively was used for measurement of bone formation (bone volume in cubic centimeters). The data were analyzed by paired t and χ2 tests via SPSS software (version 23; IBM, Armonk, NY). P < .05 was considered significant. RESULTS: Each group included 10 patients (with 6 male patients in group A and 5 male patients in group B). The mean age of patients in groups A and B was 9.5 ± 1.5 years and 9.9 ± 1.9 years, respectively. The mean volume of alveolar defects was 0.89 ± 0.29 cm3 in group A and 0.95 ± 0.27 cm3 in group B. The percentage of bone regeneration in groups A and B was 69.5% and 73.8%, respectively. CONCLUSIONS: It seems that chin symphysis bone plus allogeneic bone material plus platelet-rich fibrin is a proper combination for bone regeneration in alveolar defects with a small to moderate volume range.

Comparison of Accuracy of determining the Distance between Alveolar Crest and Cementoenamel Junction in Digital Radiography with Scanora and DentalEye Software Programs.

AIM: To compare the accuracy of determining the distance between alveolar crest and cementoenamel junction (CEJ) in digital radiography with two image processing software programs. MATERIALS AND METHODS: In this in vitro study, 63 sites in a dried human mandible underwent digital periapical radiography. The distance from the alveolar crest to the CEJ was calculated using DentalEye and Scanora software programs and compared with the standard mode (measured on the skull). Statistical analysis was performed with analysis of variance (ANOVA) and paired t-test using Statistical Package for the Social Sciences (SPSS) 23 at α = 0.05. RESULTS: There were significant differences in the distances between CEJ and the alveolar crest at the mesial surfaces as measured by the three techniques in standard mode, using DentalEye and Scanora (p-value ≤ 0.03) softwares; however, there were no significant differences between the results on distal surfaces (p-value = 0.248). CONCLUSION: Under the limitations of the present study, the measurements made to determine the distance from the CEJ to the alveolar crest with DentalEye and Scanora, relative to each other, and relative to the standard mode, were accurate only on distal surfaces of teeth. CLINICAL SIGNIFICANCE: Digital dental software programs are useful assets that can enhance the diagnosing ability and reduce the need of taking extra images.

Automatic segmentation of mandible in panoramic x-ray.

As the panoramic x-ray is the most common extraoral radiography in dentistry, segmentation of its anatomical structures facilitates diagnosis and registration of dental records. This study presents a fast and accurate method for automatic segmentation of mandible in panoramic x-rays. In the proposed four-step algorithm, a superior border is extracted through horizontal integral projections. A modified Canny edge detector accompanied by morphological operators extracts the inferior border of the mandible body. The exterior borders of ramuses are extracted through a contour tracing method based on the average model of mandible. The best-matched template is fetched from the atlas of mandibles to complete the contour of left and right processes. The algorithm was tested on a set of 95 panoramic x-rays. Evaluating the results against manual segmentations of three expert dentists showed that the method is robust. It achieved an average performance of [Formula: see text] in Dice similarity, specificity, and sensitivity.

Effect of Contrast Inversion Enhancement on the Accuracy of Endodontic File Length Determination in Digital Radiography.

OBJECTIVE: The aim of this ex vivo study was to evaluate the accuracy of endodontic file length measurement on digital periapical radiographs after application of contrast inversion digital enhancement. MATERIALS AND METHODS: Forty single-rooted single-canal mature permanent human teeth with canals measuring 20-24 mm in length were used in this study. ISO #08 K-files were placed in the root canals of the teeth. The file lengths were measured with a digital caliper as the gold standard. Standard periapical digital images were obtained with the Digora storage phosphor plates and Digora Optime scanner as the original images. The contrast inversion option of Scanora software program version 5.1 was used to produce enhanced images. Three radiologists and three endodontists measured file lengths on the original and enhanced images. The measurements were compared using repeated measures ANOVA and Bonferroni tests (α=0.05). RESULTS: There were significant differences between the measurement accuracy of the original and enhanced images (p<0.05). The enhanced images exhibited longer measurements compared to the original images. However, the two sets of digital radiographs provided significantly longer measurements compared to the gold standard (p<0.05). CONCLUSION: The contrast inversion tool of Scanora software program decreases measurement accuracy of the length of small endodontic files on digital periapical radiographs. It is suggested that contrast inversion should not be used in determining the lengths of small endodontic files.

The Efficacy of FlexMaster's IntroFile, PreRaCe and Gates Glidden Drills in Straight-Line Access: A CBCT Assessment.

INTRODUCTION: An overlooked but important part of successful root canal treatment is a straight-line access (SLA). The purpose of this in vitro study was to compare the efficacy of IntroFile and PreRaCe rotary instruments with Gates Glidden (GG) drills in gaining SLA by cone-beam computed tomography (CBCT). METHODS AND MATERIALS: A total of forty five extracted mandibular first molars were selected and mounted in dental like arches. Subsequently, they were randomly classified into three groups (n=15). After preparation of a standard access cavity, orifices of the mesiobuccal canal was reached and a #10 file was inserted to explore the canals until the file tip was visible at the apex. Then, preoperative CBCT images were taken. SLA was gained in three groups; group 1, FlexMaster's IntroFile (FM); group 2, PreRaCe (RC) and group 3, GG. Again, the first binding file at the working length (WL) was placed in the canal and postoperative CBCT images in similar positions were taken. The pre/post operative morphology of the canal was evaluated for changes. Data was analyzed using the one-way ANOVA and post-hoc Bonferroni analysis. RESULTS: The average amount of reduction in coronal canal curvature in FM, RC and GG groups was 2.43±1.79, 3.17±2.05 and 8.7±3.45, respectively. This descending trend was statistically significant. The difference between pre/post SLA changes in FM and RC groups was significant compared to GG group, while there were no significant differences between RC and FM. CONCLUSION: GG drills produced extraordinary results in reducing coronal curvature of the canal and achieving SLA. They are also more effective than nickel-titanium (NiTi) rotary instruments in canals with coronal curvature.

Evaluation of the relationship between mandibular third molar and mandibular canal by different algorithms of cone-beam computed tomography.

OBJECTIVES: Exact location of the inferior alveolar nerve (IAN) bundle is very important. The aim of this study is to evaluate the relationship between the mandibular third molar and the mandibular canal by cone-beam computed tomography. STUDY DESIGN: This was a cross-sectional study with convenience sampling. 94 mandibular CBCTs performed with CSANEX 3D machine (Soredex, Finland) and 3D system chosen. Vertical and horizontal relationship between the mandibular canal and the third molar depicted by 3D, panoramic reformat view of CBCT and cross-sectional view. Cross-sectional view was our gold standard and other view evaluated by it. RESULTS: There were significant differences between the vertical and horizontal relation of nerve and tooth in all views (p < 0.001). CONCLUSION: The results showed differences in the position of the inferior alveolar nerve with different views of CBCT, so CBCT images are not quite reliable and have possibility of error.

Effect of digital noise reduction on the accuracy of endodontic file length determination.

PURPOSE: The aim of the present study was to evaluate the measurement accuracy of endodontic file length on periapical digital radiography after application of noise reduction digital enhancement. MATERIALS AND METHODS: Thirty-five human single-rooted permanent teeth with canals measuring 20-24 mm in length were selected. ISO #08 endodontic files were placed in the root canals of the teeth. The file lengths were measured with a digital caliper as the standard value. Standard periapical digital images were obtained using the Digora digital radiographic system and a dental X-ray unit. In order to produce the enhanced images, the noise reduction option was applied. Two blinded radiologists measured the file lengths on the original and enhanced images. The measurements were compared by repeated measures ANOVA and the Bonferroni test (α=0.05). RESULTS: Both the original and enhanced digital images provided significantly longer measurements compared with the standard value (P<0.05). There were no significant differences between the measurement accuracy of the original and enhanced images (P>0.05). CONCLUSION: Noise reduction digital enhancement did not influence the measurement accuracy of the length of the thin endodontic files on the digital periapical radiographs despite the fact that noise reduction could result in the elimination of fine details of the images.