Are computed tomography images of the mandible useful in age and sex determination? A forensic science meta-analysis.

OBJECTIVES: This meta-analysis addresses the use of mandibular computed tomography (CT) scans for age and/or sex determination in forensic science. METHODS: Six databases were searched until June 2023, using the keyword "mandible" combined with keywords related to "multislice computed tomography" (MCT) or "cone-beam computed tomography" (CBCT) and keywords related to "skeletal age determination" or "sex determination analysis." MAIN RESULTS: Among the 23 studies included, 11 used MCT and 12 used CBCT to perform forensic assessments. Age determination was the aim of a single study, sex and agedeterminations were the objective of five studies, and the other studies investigated the determination of sex only. Metaanalysis could be performed only for sex determination. CONCLUSIONS: Mandible measurements are useful in sex determination, as the bicondylar and bigonial breadth are larger in males than in females. For the mandible angle, the meta-analysis results confirm sex dimorphism in CBCT scans but not in MCT scans. For age estimation, further studies are needed to prove that the mandible hole is a reliable parameter for age estimation. PROSPERO registration number: CRD42021260967.

Communication between the temporomandibular joint articular space and the extradural space in patients with temporal bone pneumatization: implications for temporomandibular joint surgery.

The pneumatization of the articular portion of the temporal bone is an anatomical variant that can modify the barrier between the articular space and the middle cranial fossa. Thus, this study aimed to identify the presence and degree of pneumatization, as well as the existence of pneumatic cell dehiscence towards the extradural or articular space determining whether it could lead to direct communication between the articular and extradural spaces. Hence, One-hundred skull computed tomography images were selected. The presence and extension of pneumatization were classified according to scores 0, 1, 2, and 3. Dehiscence towards extradural and articular spaces was recorded. In total, 200 TMJ from 100 patients were assessed and 40.5% of pneumatization cases were observed. The most prevalent score was 0 (restricted to the mastoid process), while the least prevalent score was 3 (extending beyond the crest of articular eminence). Dehiscence of the pneumatic cells towards the extradural space is more common than towards the articular space. One complete communication between the extradural and articular spaces was observed. Considering the results, it was concluded that to avoid neurological and ontological complications, awareness of the potential anatomical communications between articular and extradural spaces, particularly in patients with extensive pneumatisation, is necessary.

Stafne bone defects radiographic features in panoramic radiographs: Assessment of 91 cases.

BACKGROUND: To evaluate 91 cases of Stafne bone defect (SBD) in panoramic radiographs (PR) to determine the prevalence of different SBD variants, considering age, gender, and side. Additionally, to assess the most frequent imaging features of SBD. MATERIAL AND METHODS: Participant data were collected from 91 SBD cases with PR imaging. First, SBDs were classified according to their location, as anterior, posterior, or ramus variant. SBD imaging features were classified according to radiographic imaging findings, assessing margins, degree of internal radiolucency, shape, topographic relationship between the defect and mandibular border, location of the defect according to mandibular teeth, and locularity. The topographic relationship between the SBD and the mandibular canal was described for the inferior variant only. Mean sizes were also described. RESULTS: A total of 92 SBD cases were evaluated from 91 radiographs. One case presented multiple defects. Mean patient age was 60.80 years. Men were more affected than women. The most frequent SBD variant was the posterior variant, and the least frequent was the ramus variant. The most observed radiographic features were thick sclerotic bone margin in the entire contour of the defect, partially radiolucent internal content, oval shape, continuity with mandible base without discontinuity of mandible border, third molar region location, and unilocular shape. With the posterior variant only, the most common topographic relationship between the defect and the upper wall of the mandibular canal was the defect located below the upper wall and continuous with the inferior wall of the mandibular canal. CONCLUSIONS: The knowledge of common SBD radiographic imaging features in PR can help dental practitioners with the differential diagnosis of SBD.

Influence of pulse sequence parameters at 1.5 T and 3.0 T on MRI artefacts produced by metal-ceramic restorations.

OBJECTIVES: Susceptibility artefacts from dental materials may compromise MRI diagnosis. However, little is known regarding MRI artefacts of dental material samples with the clinical shapes used in dentistry. The present phantom study aims to clarify how pulse sequences and sequence parameters affect MRI artefacts caused by metal-ceramic restorations. METHODS: A phantom consisting of nickel-chromium metal-ceramic restorations (i.e. dental crowns and fixed bridges) and cylindrical reference specimens immersed in agar gel was imaged in 1.5 and 3.0 T MRI scanners. Gradient echo (GRE), spin echo (SE) and ultrashort echo time (UTE) pulse sequences were used. The artefact area in each image was automatically calculated from the pixel values within a region of interest. Mean values for similar pulse sequences differing in one parameter at a time were compared. A comparison between mean artefact area at 1.5 and 3.0 T, and from GRE and SE was also carried out. In addition, a parametric correlation between echo time (TE) and artefact area was performed. RESULTS: A significant correlation was found between TE and artefact area in GRE images. Higher receiver bandwidth significantly reduced artefact area in SE images. UTE images yielded the smallest artefact area at 1.5 T. In addition, a significant difference in mean artefact area was found between images at 1.5 and 3.0 T field strengths (p = 0.028) and between images from GRE and SE pulse sequences (p = 0.005). CONCLUSIONS: It is possible to compensate the effect of higher field strength on MRI artefacts by setting optimized pulse sequences for scanning patients with metal-ceramic restorations.

Thermographic characterization of masticatory muscle regions in volunteers with and without myogenous temporomandibular disorder: preliminary results.

OBJECTIVES: This study aims to conduct a non-invasive measurement of the cutaneous temperature of selected masticatory muscle regions of volunteers with and without myogenous temporomandibular disorder (TMD), using infrared thermography. METHODS: 23 females (10 myogenous TMD volunteers and 13 controls) were recruited and studied. The temperature at the surface of the facial area over the anterior temporalis and masseter muscles was assessed by medical thermography, using regional lateral views and clinical examination. RESULTS: The temperature levels measured at the masseter and anterior temporalis muscle regions in myogenous TMD volunteers (32.85 ± 0.85 and 34.37 ± 0.64 ºC, respectively) were significantly lower (p < 0.05) than those measured in controls (33.49 ± 0.92 and 34.78 ± 0.44 ºC, respectively). Medical infrared imaging indicated a mean difference of 1.4 ºC between the masseter and anterior temporalis regions. Analysis of the comparison between the absolute and normalized mean temperatures was performed using the pairwise comparison of receiver operating characteristic curves, and no statistically significant difference was observed (p > 0.05). The sensitivity and specificity of the thermographic assessment for the masseter region was of 70% and 73%, respectively and for the anterior temporalis region was of 80% and 62%, respectively. CONCLUSIONS: This method of evaluating masticatory muscle regions of this preliminary study seems to indicate that it can be used as an aid in complimentary diagnosing of TMDs.

Thermographic and clinical correlation of myofascial trigger points in the masticatory muscles.

OBJECTIVES: The aim of the study was to identify and correlate myofascial trigger points (MTPs) in the masticatory muscles, using thermography and algometry. METHODS: 26 female volunteers were recruited. The surface facial area over the masseter and anterior temporalis muscles was divided into 15 subareas on each side (n=780). This investigation consisted of three steps. The first step involved thermographic facial examination, using lateral views. The second step involved the pressure pain threshold (PPT), marking the MTP pattern areas for referred pain (n=131) and local pain (n=282) with a coloured pencil, and a photograph of the lateral face with the head in the same position as the infrared imaging. The last step was the fusion of these two images, using dedicated software (Reporter® 8.5-SP3 Professional Edition and QuickReport® 1.2, FLIR Systems, Wilsonville, OR); and the calculation of the temperature of each point. RESULTS: PPT levels measured at the points of referred pain in MTPs (1.28±0.45 kgf) were significantly lower than the points of local pain in MTPs (1.73±0.59 kgf; p<0.05). Infrared imaging indicated differences between referred and local pain in MTPs of 0.5 °C (p<0.05). Analysis of the correlation between the PPT and infrared imaging was done using the Spearman non-parametric method, in which the correlations were positive and moderate (0.4≤r<0.7). The sensitivity and specificity in MTPs were 62.5% and 71.3%, respectively, for referred pain, and 43.6% and 60.6%, respectively, for local pain. CONCLUSION: Infrared imaging measurements can provide a useful, non-invasive and non-ionizing examination for diagnosis of MTPs in masticatory muscles.

In vitro radiographic analysis of Nd:YAG-laser-irradiated dentin.

The aim of this study was to evaluate the effects of Nd:YAG laser irradiation on the dentin radiographic image. Previous studies have shown that Nd:YAG laser irradiation is capable of promoting morphological and chemical changes of the dentin surface, indicating the possibility of an alteration of its radiographic image. Dentin of 2-mm-thick mid-coronal sections from 68 extracted posterior teeth was irradiated for 30 s by a Nd:YAG laser (lambda=1,064 nm) on one half of its surface area. The other half was left as a control. The irradiation parameters were: 80 mJ/pulse, 0.8 W, 10 Hz, with a 320-mum flexible quartz optic fiber in contact mode. The 68 samples were radiographed with a 70-kV X-ray setup. The focus-film distance was established as 30 cm and there was no distance between the object and the film. The X-ray exposure time was set as 0.16 s and the radiographic film used was an F-speed dental film. The obtained radiographic images were submitted to a densitometric analysis. The images analyzed showed that there were statistically significant differences between the density of the irradiated dentin images and the non-irradiated dentin images. The image density data showed that the irradiated dentin radiographic images were 6.36% more radiopaque than the non-irradiated dentin images. The Nd:YAG laser irradiation of dentin is able to alter its radiographic image, producing more radiopaque images of the irradiated dentin.

[Ameloblastic transformation of an odontogenic cyst]. / Transformação ameloblástica de um cisto odontogênico.

The author relate a case of ameloblastic changing in an odontologenic cyst located in the anterior region of the mandible, in a man fifty-four years old. They comment the importance of a complete examination when someone finds a pathology.