Fractal analysis of the effects on mandibular bone of botulinum toxin therapy of the masseter muscle in patients with bruxism.

OBJECTIVE: We examined changes in the mandibular angle, ramus, and condylar neck of patients with bruxism after botulinum toxin-A (BTX-A) injection into the masseter muscle as calculated with fractal analysis (FA) on panoramic radiographs (PRs). METHODS: We examined the PRs of 3 groups of 22 patients each (n = 66) obtained upon presentation and 6 months later. One group included healthy controls without bruxism, one group included patients with untreated bruxism, and one group included patients with bruxism who had undergone BTX-A injection into the masseter muscle. We performed FA of the bilateral angle, ramus, and condylar neck of the PRs to calculate fractal dimension (FD). RESULTS: The FD values of the angle on the second PRs of the untreated bruxism group were significantly higher than those of the other groups (P = .026), specifically when compared to the BTX-A injection group (P = .017). The FD values in the angle and ramus of the bruxism group were significantly higher on the second PRs (P ≤..005)) Conversely, the FD values in the angle of the BTX-A injection group were significantly lower on the second PR (P = .039). CONCLUSIONS: Masseter muscle hyperactivity due to bruxism increases bone density in masseter muscle attachment regions. BTX-A injection restricts muscle activity, thereby chnging bone structure and decreasing FD.

Morphology and morphometry of the foramen venosum: a radiographic study of CBCT images and literature review.

PURPOSE: The goal of this study was to assess the morphological variations, location, and morphometric measurements of the foramen venosum (FV) and analyse its interrelationships with other foramina on cone-beam computed tomography (CBCT) scans. METHODS: A total of 269 individual CBCT scans were evaluated retrospectively. The presence or absence of FVs and their diameter, shape, and confluence to foramen ovale were recorded. The distances between anatomic structures and the FV were calculated. Appropriate statistical analysis was performed for the collected data. RESULTS: Of the 269 cases studied, nine were excluded due to duplicate foramina that made statistical analysis difficult. In the 260 evaluated scans, the FV was identified in 190 individuals (73.1%). The incidence was 148 (56.9%) on the right side and 152 (58.5%) on the left side. The FV was present unilaterally in 80 (30.8%) and bilaterally in 110 (42.3%) out of the 260 individuals. The mean maximum diameter of FV was 1.75 ± 1.27 mm, and no significant differences related to gender and age were detected (p < 0.05). The most prevalent foramen shape was the oval type (45.9% on the right side and 40.8% on the left side). CONCLUSION: FV is a very frequent anatomical variation. This foramen can exist either bilaterally or unilaterally. No significant differences related to sex, side, or age could be found in the present study. The anatomic characteristics of FV should be considered during interventions in the middle cranial fossa. CBCT imaging with lower radiation doses and thin slices may prove useful before surgical skull-base procedures.

Assessment of zygomatic bone using cone beam computed tomography in a Turkish population.

OBJECTIVE: To provide linear and volumetric measurements of zygomatic bone using cone beam computed tomography (CBCT) images. STUDY DESIGN: CBCT images were assessed for 198 patients. Posterior and anterior zygomatic bone widths (M1 and M2), zygomatic bone projection (M3), zygomatic bone height (M4), combined zygomatic arch diameter (M5), maximum cortical thickness (M6), gray value obtained from maximum cortical thickness region (M7), minimum cortical thickness (M8), and gray value obtained from minimum cortical thickness region (M9) were measured. Volume and surface area measurements of the zygomatic bone were also conducted. Sex, age, and side were recorded for each patient. General linear model analysis of variance (ANOVA) was performed (P < .05). RESULTS: Age (P < .001) and gender (P = .001) significantly affected M1. Gender significantly affected M3 (P = .003) and M4 (P = .000), with higher values for men. Gender (P = .000) and age (P = .000) significantly affected M5 variation. Only age had a significant effect on M6 variation, with an increase with age (P < .015). Only gender had a significant effect on M7 (P = .005), M8 (P = .000), and M9 (P = .004), with higher values for men. All the factors significantly affected zygomatic bone volume variation (gender, P = .000; age, P = .000; and side, P < .004). CONCLUSION: Detailed examination of the zygomatic bone region can be performed with CBCT images.

CBCT quantitative evaluation of mandibular lingual concavities in dental implant patients.

PURPOSE: The purpose of this study was to evaluate the prevalence of mandibular lingual concavities and to measure them using CBCT (Cone-Beam Computerized Tomography). METHODS: In this study, CBCT scans of 200 patients requiring dental implants were assessed for lingual concavities. Reconstructed CBCT images were transferred as DICOM files to the 3D DOCTOR software program, and metric, volumetric, and surface area measurements were obtained. Two-way mixed ANOVA was used to model side (left/right, anterior), measurement type, and gender with side and type taken as within-subject variables, gender as between-subject variables, and age as a covariate. A comparison between the dentate and edentulous groups in the samples with lingual concavities was performed using an unpaired Student's t test. RESULTS: Submandibular concavity mean depth and volume were found to be 2.4 mm and 130.7 mm(3), whereas mean depth and volume of sublingual concavities were found to be 1.3 mm and 26.5 mm(3). Significant inverse ratios were found between age and volume and between age and surface area (p < 0.05). All measurements were higher in males than females, but the differences were not statistically significant. The differences between the presence of concavity (sublingual, right, and left submandibular) and dental status (dentate/edentulous) were statistically insignificant (p > 0.05). CONCLUSION: Mandibular lingual concavity dimensions were found to vary by age, location, and the presence/absence of teeth. Third party software can be used to generate 3-dimensional models that provide useful information about shape, size, and location of sublingual and submandibular concavities prior to implant placement.

A comparison of peripheral marginal bone loss at dental implants measured with conventional intraoral film and digitized radiographs.

The purpose of the present study was to examine the effects of conventional and bone-condensing implantation techniques and time (6 and 12 months after implantation) on levels of marginal bone surrounding implants and to assess the level of agreement between measurements made using digitized intraoral images and film. The study group consisted of 14 healthy patients (9 female, 5 male; age range, 23-59 years; mean age, 41.1 years) with 28 single-tooth dental implants. In each patient, an implant was placed on one side using a conventional technique and on the opposite side using a bone-condensing technique. Film radiographs were taken at 6 and 12 months following implant placement and were digitized at 300 dpi and 600 dpi using a laser scanner. All scanned images were stored as both TIFF and JPEG files. A single observer twice measured distal and mesial marginal bone loss from film and digitized images. At the mesial site, there was a significant main effect of time (6 and 12 months after implantation) on the measurement of bone loss, F(1, 26) = 6.08, P = .02, but no significant main effect of implantation technique, F(1, 26) = 1.56, P = .223, and no significant interaction between time and technique, F(1, 26) = 2.09, P = .160. Similarly, at the distal site, there was a significant main effect of time on the measurement of bone loss, F(1, 26) = 14.1, P = .001, but no significant main effect of implantation technique, F(1, 26) = 1.21, P = .281. However, in contrast to the mesial site, there was also significant interaction between technique and time on the distal site, F(1, 26) = 4.974, P = .035. Intraobserver intraclass correlation coefficients and repeatability measurements showed high agreement for all image types. The bone-condensing technique resulted in greater marginal bone loss. Marginal bone measurements made using digitized intraoral images and conventional film showed high levels of agreement.

Comparative assessment of subjective image quality of cross-sectional cone-beam computed tomography scans.

Since the introduction of cone-beam computed tomography (CBCT), several novel systems with different technical specifications and settings have become commercially available. Therefore, it is essential to evaluate CBCT systems for differences in the subjective quality of images obtained for various dental procedures. We evaluated the subjective image quality of cross-sectional scans obtained from various CBCT systems. Images of three cadaver mandibles were obtained from four different CBCT units: 1) Veraviewepocs 3D 40 × 40 mm field of view (FOV) (voxel size: 0.125 × 0.125 × 0.125 mm), 2) Iluma, low-resolution (voxel size: 0.3 × 0.3 × 0.3 mm), 3) Kodak, 50 × 3.7 cm FOV (voxel size: 0.076 × 0.076 × 0.076 mm), and 4) Vatech 12 × 8.5cm FOV (voxel size: 0.160 × 0.160 × 0.160 mm). We assessed subjective image quality and the visibility of 10 specific features, namely, caries, amalgam restoration, final implant drill, root canal filling, metal crown, mandibular canal, mental foramen, tooth (periodontal ligament space and lamina dura), trabecular pattern, and soft tissue. Images were viewed and scored by five calibrated observers, and image quality was ranked from best to worst. The Veraviewepocs 3D had the highest quality images for most of the assessed features, whereas the Iluma low-resolution scans were rated as the lowest quality images.

Evaluation of bifid mandibular canals with cone-beam computed tomography in a Turkish adult population: a retrospective study.

PURPOSE: Knowing the anatomic location and also variations of the mandibular canal is especially important for surgical procedures on mandible such as dental implant surgery, impacted molar extraction and sagittal split ramus osteotomy. The purpose of this study was to clarify the incidence and location of bifid mandibular canals in an adult Turkish population to avoid complications during surgical procedures. METHODS: A retrospective study using cone beam CT images was performed to evaluate bifid mandibular canal in mandible of 242 patients. Both right and left sides were studied (n = 484). Axial, sagittal, cross-sectional and panoramic images were evaluated, and three-dimensional (3D) images were also reconstructed and evaluated, as necessary. The course and length of bifid mandibular canals and the superior and inferior angles between canals were measured. RESULTS: Bifid mandibular canals were observed in 225 (46.5%) of 484 sides examined. The most frequently encountered type of bifid canal was the forward canal (29.80%), followed by the retromolar (28.10%) the buccolingual (14.50%) and the dental canal type (8.30%). Mean lengths of bifid canals were 13.6 mm in the right side and 14.1 mm in the left side. Mean superior angles were 139° on the right and 141° on the left side, whereas mean inferior angles were 38° on the right side and 32° on the left side. No statistically significant differences were found in the lengths or angles between the right and left sides and also for gender (p < 0.05). CONCLUSIONS: This study, which utilized CBCT images, uncovered a higher prevalence of bifid mandibular canals than what has been reported in previous studies using conventional radiography techniques.

Accuracy of CBCT measurements of a human skull.

The purpose of this study is to assess the accuracy and reproducibility of cone-beam computed tomography (CBCT) measurements of a human dry skull by comparing them to direct digital caliper measurements. Heated gutta-percha was used to mark 13 specific distances on a human skull, and the distances were directly measured using a digital caliper and on CBCT images obtained with Iluma (3M Imtec, OK, USA) and 3D Accuitomo 170 (3D Accuitomo; J Morita Mfg. Corp., Kyoto, Japan) CBCT imaging systems. Iluma images were obtained at 120 kVp and 3.8 mA and reconstructed using voxel sizes of 0.2 and 0.3 mm(3). Accuitomo images were obtained at 60 kVp and 2 mA and a voxel size of 0.250 mm(3). In addition, 3-D reconstructions were produced from images obtained from both systems. All measurements were made independently by three trained observers and were repeated after an interval of 1 week. Agreement between observers and image type was assessed by calculating Pearson correlation coefficients, with a level of significance set at p < 0.05. Pearson correlation coefficients between readings ranged from 0.995 to 1 for all image types. Correlations among observers were also very high, ranging from 0.992 to 1 for the first reading and from 0.992 to 1 for the second reading for the different image types. All CBCT image measurements were identical and highly correlated with digital caliper measurements. Accuracy of measurements of various distances on a human skull obtained from different CBCT units and image types is comparable to that of digital caliper measurements.

Occlusal caries detection by using a cone-beam CT with different voxel resolutions and a digital intraoral sensor.

OBJECTIVES: This study assessed in vitro the diagnostic ability of intraoral digital CCD sensor images and CBCT images at different voxel resolutions in the detection of occlusal caries. STUDY DESIGN: The study sample consisted of 130 mandibular molars (61 sound and 69 diseased). Digital intraoral images and CBCT images were obtained at 0.1-mm, 0.2-mm, and 0.3-mm voxel sizes. All images were evaluated separately by 4 observers, and evaluations were repeated after a 4-week interval. Weighted kappa coefficients were calculated to assess intra- and interobserver agreement for each image set, and scores were compared with the histological gold. For the estimation of nonparametric imaging modality effects and tests of hypotheses, SAS 9.0 and SAS macros were used for F1_LD_F1 factorial design. An a priori level of significance of P equals .05 was used. RESULTS: High intra- and interobserver agreements were obtained (Kappa value range: 0.825 to 0.948 for intraobserver agreement and 0.700 to 0.903 for interobserver agreement). Estimated relative treatment effects (RTE) ranged from 0.26 to 0.85, which varied with caries level and imaging modality. Differences between RTE values obtained with ultra-resolution and high- and low-resolution images were not statistically significant for all caries levels. Comparing 3D and intraoral imaging modalities among caries levels showed that imaging modality performance was different for deep enamel, superficial dentine, and deep dentine; however, imaging modality performance was not statistically different for healthy and superficial enamel caries groups. CONCLUSION: At all voxel sizes, CBCT images can be considered a tool for use in the diagnosis of occlusal caries.

Interpretation of chemically created periapical lesions using 2 different dental cone-beam computerized tomography units, an intraoral digital sensor, and conventional film.

OBJECTIVE: To assess the diagnostic potential of 2 different cone-beam computerized tomography (CT) units and compare this with intraoral digital and conventional film in the detection of chemically created periapical lesions. STUDY DESIGN: Periapical lesions were created chemically in 27 intact roots of 23 teeth (6 incisors, 4 canines, 6 premolars, and 7 molars). Cone-beam CT and digital and film images of the teeth were obtained before and after the lesions were created. Three observers separately used a 5-point scale to rate the images for the presence or absence of periapical pathology. Images were scored twice by each observer, with an interval of 4 weeks. Kappa values were calculated to assess intra- and interobserver agreement. Data were analyzed using repeated-measures analysis of variance for nested designs. R(2) values were used to assess the models for each observer for each method. Differences between observers and methods were tested for statistical significance with the paired t test. RESULTS: Kappa coefficients for intraobserver agreement ranged from 0.196 to 0.542 for the 2-dimensional (2D) images and from 0.533 to 0.699 for the cone-beam CT images, whereas kappa coefficients for interobserver agreement ranged from 0.223 to 0.302 for the 2D images and from 0.417 to 0.461 for the cone-beam CT images. The R(2) values for each observer showed that cone-beam CT images were superior to 2D intraoral images. There was no difference between the 2 cone-beam CT units tested (P > .05), and no difference was found between the 2 intraoral radiographic techniques tested (P > .05). CONCLUSION: The 2 cone-beam CT units tested performed similarly, and both performed better than intraoral digital and film radiography in detecting chemically created periapical lesions.

Assessment of blood mercury levels in practicing Turkish clinicians, dental students, and dental nurses.

OBJECTIVES: Potential sources of exposure of the dental health team and their patients to mercury vapor in the dental clinic include accidental spillage of elemental mercury, use of mechanical amalgamators, and dry cutting of old amalgam restorations using high-speed instrumentation. The purpose of this study was to evaluate the extent of mercury exposure in Turkish dental staff by cold-vapor atomic absorption spectrometry. METHOD AND MATERIALS: A total of 211 clinicians, dental students, and dental nurses answered a questionnaire concerning sex, age, occupation, number of amalgam restorations performed per week, number of amalgam restorations removed per week, methods of trituration, number of amalgam restorations present in their own mouths, frequency of fish consumption, smoking, vitamin intake, and bruxism. For each subject, a 5-mL sample of whole blood was drawn and frozen until the time of analysis. Blood mercury levels were measured by means of cold-vapor atomic absorption spectrometry. Blood mercury levels were also analyzed in a control group of 58 non-dental-staff blood donors. RESULTS: Normal blood mercury values are considered to be in the range of 0 to 5 ng Hg/mL. Of the dental staff evaluated, 51.7% had a blood concentration of mercury less than 5 ng Hg/mL, and 33.6% had a blood concentration above 5 ng Hg/mL. The difference between the test and control groups was statistically significant (P < .01). CONCLUSION: Mercury is being absorbed as a result of dental practice but that although there is, in general, a low level of mercury contamination in the dental operatory because of amalgam work, sufficient care is being taken to prevent higher levels of contamination with an increased use of mercury.

Assessment of bone density differences between conventional and bone-condensing techniques using dual energy x-ray absorptiometry and radiography.

OBJECTIVES: We used dual energy x-ray absorptiometry (DEXA) and periapical radiography to assess bone density differences after conventional and bone-condensing dental implant techniques. STUDY DESIGN: Single-tooth dental implants were placed by both conventional and bone-condensing techniques in 14 patients with bilateral missing teeth. Dual energy x-ray absorptiometry was used to calculate bone mineral density (BMD) and bone mineral content (BMC) before and 6 and 12 months after implant placement. Furthermore, photodensitometry of periapical radiographs was also assessed. RESULTS: The success rate was 92.9% for the conventional technique and 71.5% for the bone-condensing technique. The BMD was observed to be significantly higher 6 and 12 months after implant placement. The BMC and photodensitometry were significantly increased 6 months after implant placement but showed no further after 12 months. CONCLUSIONS: There were no significant differences in BMD, BMC, and photodensitometry between the two implant placement techniques. However, success rate of the conventional technique was greater than the bone-condensing technique, which may be the result of trabecular fracture associated with the bone-condensing.

Rhinolithiasis: an uncommon entity of the nasal cavity.

Rhinoliths are uncommon foreign bodies of the nose formed by in situ calcification of intranasal endogenous or exogenous foreign material. They are often an asymptomatic condition diagnosed accidentally during a routine examination. Although nasal foreign bodies are more frequently seen in children, and appear to be more common in women, they have been reported in patients of all ages. This article describes a case of rhinolith involving a 38-year-old male. The etiology, thin-sectioned microscopic findings, differential diagnoses, and treatment are also discussed.

Prevalence and variations of pneumatized articular eminence: a study from Turkey.

OBJECTIVES: Pneumatized articular eminence or tubercule (PAT) is an air cell cavity in the zygomatic process of the temporal bone that is similar to air cells in the mastoid process and ethmoid bone. The purpose of this study was to determine the prevalence and variations of PAT among an outpatient dental clinic population at Ankara University, Turkey, to make a contribution to the few current studies about PAT. STUDY DESIGN: A total of 1006 panoramic radiographs were retrospectively investigated for the prevalence and radiographic features of PAT. Meta-analysis was done for 4 large case series in the literature and our case series. Furthermore, we performed Chi-square test to evaluate age, gender, localization, and prevalence differences among 5 case series including ours. RESULTS: PAT was found in 19 (1.88%) patients with a mean age of 36.6 (SD 21.06) years. Twelve cases (63.1%) occurred in females and 7 cases (36.9%) occurred in males. Bilateral PAT was found in 7 patients (36.9%). Meta-analysis of 5 large case series revealed a total of 6669 patients, of whom 115 had PAT (1.76% prevalence) occurring over an age range of 7 to 90 years. Fifty (43.47%) occurred in males and 65 (56.53%) occurred in females. Bilateral PAT was found in 28 (24.34%) patients. The result of Chi-square test showed no statistically significant differences among the 5 studies with respect to age, gender, localization, and prevalence. CONCLUSIONS: Knowledge about these structures is helpful for the interpretation of imaging such as panoramic radiographs and provides valuable information to understand the spread and differential diagnosis of pathological entities in this region. Moreover, clinicians who are planning to perform temporomandibular joint surgery are advised to assess radiographic imaging thoroughly before the surgery to avoid intra-operative complications and reconstruction.