Thiago de Oliveira Gamba

Influence of cone-beam computed tomography image artifacts on the determination of dental arch measurements

OBJECTIVE To compare dental plaster model (DPM) and cone-beam computed tomography (CBCT) in the measurement of the dental arches, and investigate whether CBCT image artifacts compromise the reliability of such measurements. MATERIALS AND METHODS Twenty patients were divided into two groups based on the presence or absence of metallic restorations in the posterior teeth. Both dental arches of the patients were scanned with the CBCT unit i-CAT, and DPMs were obtained. Two examiners obtained eight arch measurements on the CBCT images and DPMs and repeated this procedure 15 days later. The arch measurements of each patient group were compared separately by the Wilcoxon rank sum (Mann-Whitney U) test, with a significance level of 5% (α  =  .05). Intraclass correlation measured the level of intraobserver agreement. RESULTS Patients with healthy teeth showed no significant difference between all DPM and CBCT arch measurements (P > .05). Patients with metallic restoration showed significant difference between DPM and CBCT for the majority of the arch measurements (P > .05). The two examiners showed excellent intraobserver agreement for both measuring methods with intraclass correlation coefficient higher than 0.95. CONCLUSION CBCT provided the same accuracy as DPM in the measurement of the dental arches, and was negatively influenced by the presence of image artifacts.

Lateral pterygoid muscle volume and migraine in patients with temporomandibular disorders

Purpose Lateral pterygoid muscle (LPM) plays an important role in jaw movement and has been implicated in Temporomandibular disorders (TMDs). Migraine has been described as a common symptom in patients with TMDs and may be related to muscle hyperactivity. This study aimed to compare LPM volume in individuals with and without migraine, using segmentation of the LPM in magnetic resonance (MR) imaging of the TMJ. Materials and Methods Twenty patients with migraine and 20 volunteers without migraine underwent a clinical examination of the TMJ, according to the Research Diagnostic Criteria for TMDs. MR imaging was performed and the LPM was segmented using the ITK-SNAP 1.4.1 software, which calculates the volume of each segmented structure in voxels per cubic millimeter. The chi-squared test and the Fishers exact test were used to relate the TMD variables obtained from the MR images and clinical examinations to the presence of migraine. Logistic binary regression was used to determine the importance of each factor for predicting the presence of a migraine headache. Results Patients with TMDs and migraine tended to have hypertrophy of the LPM (58.7%). In addition, abnormal mandibular movements (61.2%) and disc displacement (70.0%) were found to be the most common signs in patients with TMDs and migraine. Conclusion In patients with TMDs and simultaneous migraine, the LPM tends to be hypertrophic. LPM segmentation on MR imaging may be an alternative method to study this muscle in such patients because the hypertrophic LPM is not always palpable.

Utility of panoramic radiography for identification of the pubertal growth period

INTRODUCTION Our aim in this study was to investigate the association between dental mineralization stages and the periods of the pubertal growth spurt (PGS). METHODS The sample included panoramic and hand-wrist radiographs from 491 subjects (222 boys, 269 girls) aged 7 to 17 years. Dental development was rated, and skeletal maturation was evaluated. The relevant associations were investigated by analysis of ordinal multinomial logistic regression. RESULTS The second molar (odds ratio [OR] = 4.34) and the first premolar (OR = 2.45) were the best growth predictors for girls. For boys, the second molar (OR = 6.80), second premolar (OR = 2.41), and canine (OR = 3.21) proved to be the best predictors. Stages D and E of the second molar for girls, and stages E and F for boys, corresponded to the onset of the accelerated growth spurt. Stage F of the second molar for girls and stage G for boys corresponded to the peak of the PGS. At the end of the PGS, most teeth had already attained apical closure. In girls, however, most second molars were found at stage G. CONCLUSIONS An association exists between the dental mineralization stages and the periods of the PGS, especially for second molars. Panoramic radiographs can be used as the first diagnostic tool to estimate the pubertal growth period.

Evaluation of cone beam computed tomography and periapical radiography in the diagnosis of root resorption

BACKGROUND This study aimed to evaluate the accuracy of cone beam computed tomography (CBCT) and periapical radiography in diagnosing root resorption and verify the influence of filling material in detecting these lesions. METHODS Digital periapical radiographs and CBCT images of patients with root resorption and a history of dental trauma from a radiology clinic were reviewed retrospectively. The sample comprised 40 teeth with root resorption and 20 normal teeth as controls. Images were analysed by two radiologists and two endodontists. The sensitivity, specificity and accuracy were determined. The kappa coefficient assessed interobserver agreement and the t test determined significant differences between the imaging methods. RESULTS The accuracy of CBCT in diagnosing external (P = 0.0144) and internal (P = 0.0038) inflammatory resorption was significantly higher than for periapical radiography. For replacement resorption, no statistical difference was noted (P > 0.05). In endodontically treated teeth, CBCT was statistically superior in diagnosing root resorption (P = 0.0138). CONCLUSIONS CBCT was superior to digital periapical radiography in diagnosing external and internal inflammatory root resorption after dental trauma and can be considered in the differential diagnosis of resorptive lesions in teeth with endodontic treatment.

A Wormian Bone, Mimicking an Entry Gunshot Wound of the Skull, in an Anthropological Specimen.

Wormian bones (WB) are irregular small cranial ossicles found along suture lines and fontanels. In Brazil, gunshot wounds to the skull are quite common in young individuals. Nevertheless, as far as we know, this is the first report of a WB giving an erroneous aspect of gunshot entrance due to its displacement position. The present manuscript describes the case of a Brazilian young man who died due to ballistic trauma, where a gaping bony defect on the right side of the skull was thought to be the exit wound of an injury related to the destruction found on the left side, highly suggestive of firearm injury. Thus, this case study has brought to light similarities between a traumatic lesion and an orifice of a WB, with emphasis on differential diagnosis during routine anthropological examinations.

Comparison of panoramic radiography and CBCT to identify maxillary posterior roots invading the maxillary sinus

OBJECTIVES Given the limitations of panoramic radiography for assessing topographic relationship of maxillary teeth with sinus floor, the purpose of this study was to assess signs on panoramic radiography that could predict root protrusion into the sinus. METHODS A total of 46 individuals (330 maxillary posterior teeth) who underwent panoramic radiography and CBCT were enrolled. The relationship between the posterior teeth and the maxillary sinus and panoramic radiography signs (projection of the root apices, interruption of the maxillary sinus floor, lamina dura, darkening in the root apices, and superiorly curving sinus floor enveloping the associated tooth root) associated with protrusion of root apices into the sinus were evaluated. RESULTS There were differences between the imaging modalities about the positioning of the root apices regarding the sinus (p < 0.05). Only the projecting of the root apices and the interruption of the sinus floor on panoramic radiography were predictors for the root protrusion (p < 0.05). No significant association was observed for the other panoramic radiography signs (p > 0.05). CONCLUSIONS The root projection into the sinus and the interruption of the sinus floor are indicative signs of root protrusion into the sinus on CBCT.

Aggressive unicystic ameloblastoma affecting the posterior mandible: late diagnosis during orthodontic treatment

Maxillofacial images must be examined to find pathologies not identified during clinical examination. Unicystic ameloblastoma (UA) extending to the mandibular body and ramus was neglected on initial panoramic radiographic examination. After orthodontic therapy, a huge lesion was observed clinically and through imaging exams. After the conservative surgery, no recurrence was observed during five years of follow-up. This case emphasized the need for careful evaluation of patient images focusing on the oral diagnosis before any dental treatment planning, including orthodontic therapy.

Validation study of a new method for sexual prediction based on CBCT analysis of maxillary sinus and mandibular canal

OBJECTIVE The aim of this study was to evaluate the accuracy of two craniometric methods for sexual prediction (SP) using cone-beam computed tomography (CBCT) in the Dutch population and to construct a formula for each method and then the two combined. DESIGN One-hundred sixty CBCT images were selected from a Dutch database (80 males and 80 females). The images were analyzed by two examiners taking seven measurements in the maxillary sinus (MS) region (first method) and nine in the mandibular canal (MC) region (second method). The most predictive measurements in both methods were used to develop an equation to determine the accuracy of each method. RESULTS All measurements showed statistical difference between genders. Logistic regression results showed two variables with greater SP index with 75% accuracy in the first method and four variables with 71.9% accuracy in the second. The two methods combined showed another four variables with 78.5% accuracy. CONCLUSION All measurements showed statistically significant differences between sexes. The SP accuracy values were 75% for first 71.9% for the second method. When the two methods were combined, the accuracy increased to 78.5%. The formulas developed in this study can be applied as a complementary method for human identification in the Dutch population.

Squamous Odontogenic Tumor: Literature Review Focusing on the Radiographic Features and Differential Diagnosis

Since its first publication in 1975, the squamous odontogenic tumor remains the rarest odontogenic lesion, with around 50 cases in the English-language literature in which the microscopic characteristics are frequently very well demonstrated. However, articles which discuss the radiographic aspects are scarce, especially with emphasis on the differential diagnosis. The present treatise proposes an assessment of jaw lesions with the same radiographic characteristics of the squamous odontogenic tumor to clarify the main findings for dental clinicians during routine diagnosis.

Cone-Beam Computed Tomography: An Accurate Diagnostic Tool inDental Practice for Evaluation of Anatomic Variations in Maxillary BoneSepta

Background: Advanced knowledge of the shape and length of the maxillary sinus and its internal septa is useful for treatment planning of extraction, implant and sinus lift procedures. Purpose: This study evaluates the prevalence, morphology, orientation, location, height, and length of bone septa in the maxillary sinus using cone-beam computed tomography (CBCT) images, for completely dentate versus partially or fully edentulous patients. Also, since dental extractions may induce formation of sinus septa, this study assesses the correlation between edentulism and prevalence of the maxillary sinus septa. Material and methods: Four hundred forty-three CBCT images were selected to evaluate the prevalence of a septum in the maxillary sinus to perform an anatomic study of septum morphology. All images were evaluated by one an expert in oral radiology. The χ2 test was used to verify the relationship between the presence of septa and sex, age, and edentulism status. Variance analysis and the Tukey test showed a relationship between partial or full edentulism and the height and length of the maxillary sinus septum. Results: A maxillary sinus septum was found in 50.1% of the study sample size. 69.8% of patients with a septum were partially edentulous. Gender did not correlation with septum prevalence. The length of the septum in the transverse orientation, and the location of the septum in the medial aspect of the sinus, both correlated with tooth loss. Conclusions: Maxillary sinus bone septa are more prevalent in partly or fully edentulous populations. Given the diversity of septa morphology among patients, a detailed evaluation of each patient’s septa using CBCT is useful for customizing bone graft and implant placement treatment planning for each patient.