Evaluation of the Maxillary Sinus of Patients with Maxillary Posterior Implants: A CBCT Cross-Sectional Study.

BACKGROUND: During oral rehabilitation, dental implants in the posterior maxilla can penetrate the maxillary sinus. The aim was to evaluate the presence of maxillary sinus abnormalities in patients with dental implants in the posterior maxillary region using cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: This was a retrospective cross-sectional study, and CBCT scans of 199 patients (459 dental implants) were evaluated. Implants were assessed according to their relative location to the maxillary sinus floor (up to 2 mm from the maxillary sinus cortex, within 2 mm to intimate contact with the maxillary sinus cortex, apical third inside the maxillary sinus, two-thirds or more inside the maxillary sinus) and bone-fixation tissue (Alveolar ridge or Bone graft). Maxillary sinus abnormalities were classified. Kappa and Weighted Kappa and the Kruskal-Wallis test were applied. RESULTS: A higher prevalence of mucosal thickening and non-specific opacification were observed in implants located within 2 mm to intimate contact with the cortex of the maxillary sinus floor. Of the 66 implants with apical thirds located inside the maxillary sinus, 31 (46.7%) were associated with sinus abnormalities and of all implants (n = 5) with two-thirds or more located inside the maxillary sinus, all of these were associated with sinus abnormalities. No association was observed in relation to implant bone-fixation tissue. CONCLUSIONS: This study found a significant association between dental implant placement near or within the sinus and sinus abnormalities, mainly mucosal thickening and non-specific opacification.

Evaluation of different teaching methods in the radiographic diagnosis of proximal carious lesions.

OBJECTIVES: To evaluate four different teaching methodologies in the radiographic diagnosis of proximal carious lesions and in the students' perception of these methodologies. METHODS: 71 undergraduate dental students were subdivided into 4 groups according to the teaching methodologies used (traditional, hybrid, e-learning and problem-based learning). All methods were applied by two properly trained researchers. Initially, students completed a pre-methodology test (index test). After applying the teaching methodologies, the students were submitted to a post-methodology test containing periapical radiographs for evaluation of proximal carious lesions. Then, the students answered a questionnaire to verify their perception of the different teaching methodologies. Statistical analysis was done. RESULTS: There were no relationship between the results of pre- and post-methodologies tests, irrespective of the teaching methodology employed (p > 0.05). No differences between the teaching methodologies studied (p > 0.05) were found regarding the amount of correct answers. However, the students who participated in the active (e-learning and problem-based learning) and hybrid teaching methodology reported a positive impact in relation to their diagnostic skills at the questionnaire. CONCLUSIONS: All the tested methodologies had a similar performance; however, the traditional methodology showed less acceptance by the students when analyzed subjectively and comparatively. The results of the present study increase comprehension about teaching methodologies for radiographic diagnosis of proximal carious lesions, and there is a potential to build on the knowledge base and provide practical support for students and educators.

The influence of different scan resolutions on the detection of proximal caries lesions.

PURPOSE: This study was conducted to evaluate the effect of different spatial resolutions of a photostimulable phosphor plate (PSP) radiography system on the detection of proximal caries lesions. MATERIALS AND METHODS: Forty-five extracted human permanent teeth were radiographed using a PSP system (VistaScan Perio Plus) and scanned at the 4 resolutions (10 lp/mm, 20 lp/mm, 25 lp/mm, and 40 lp/mm) available in the system. Three independent examiners scored the images for the presence and absence of proximal caries lesions using a 5-point scale. The presence or absence of caries was confirmed by histological sections of the examined teeth (defined as the gold standard). Intra- and inter-observer reproducibility was calculated by the weighted kappa test. One-way analysis of variance with the post hoc Tukey test was used to compare the area under the receiver operating characteristic curve for the classifications made with each resolution. RESULTS: For the detection of enamel lesions, the spatial resolution of 10 lp/mm was significantly superior to the other resolutions. However, the spatial resolution did not affect the detection of caries lesions in dentin (P>0.05). CONCLUSION: Spatial resolution may influence the accuracy of the detection of incipient caries lesions in radiographs with PSP plates. Images with low spatial resolution seem to be more appropriate for this purpose.

Clinical implications, diagnosis, and treatment of a giant frontoethmoid osteoma.

Osteomas are benign, asymptomatic fibro-osseous tumors that are most commonly observed in the paranasal sinuses and sometimes are found in imaging examinations that were taken for other reasons. Giant osteomas are rarely found in the frontal and ethmoid sinuses but, when they are, they may cause intracranial and orbital complications. The aims of this case report are to describe a frontoethmoid osteoma in a 40-year-old woman, discuss the characteristics of this lesion through cone beam computed tomography (CBCT) imaging, and review the options for treatment. A CBCT examination performed for the purpose of orthodontic diagnosis revealed the presence of a large, well-defined, lobular, hyperdense mass that occupied a sizeable area of the frontal sinus and extended to the ethmoid sinus. The patient did not report any pain. Based on the physical and imaging characteristics of the mass, the location and size of the lesion, and the patient's age, the diagnosis was a giant frontoethmoid osteoma. Due to its enhanced field of view, CBCT may enable earlier diagnosis of lesions that affect the maxillofacial region.

Feasibility of micro-computed tomography to detect and classify proximal caries lesions in vitro.

BACKGROUND: Micro-computed tomography (micro-CT) has been widely described as a nondestructive in vitro imaging method although its accuracy for caries detection is still unclear. The aim of this study was to investigate the feasibility of micro-CT to detect and classify proximal caries lesions in posterior teeth, using different protocols. MATERIALS AND METHODS: In this in vitro study, crowns of 122 human teeth were scanned with Skyscan 1174 (Bruker, Kontich, Belgium) using the full-scan mode (360°). Reconstruction of 900 basis images was performed using NRecon Software (Bruker, Kontich, Belgium) for the protocol 1 (full-scan mode 360°), and 450 basis images were used to reconstruct the protocol 2 (half-scan mode 180°). Three observers analyzed the reconstructed images concerning the presence and depth of proximal caries lesions (244 surfaces). To determine the presence/absence and depth of caries lesions, histological examination was conducted as reference standard level of significance McNemar and McNemar-Bowker tests compared the methods studied and the gold standard (P < 0.05). RESULTS: The intra- and inter-observer agreement for both methods ranged from moderate to excellent. There was no difference between both micro-CT methods and histology for the presence of lesions (P > 0.05). However, both methods differed with the reference standard for depth (P < 0.05). The disagreement occurred mostly in cases of enamel lesions. The highest diagnostic values were found for 180° rotation. Micro-CT performed well in detecting caries lesions compared to histology, meanwhile the classification of their depth presented lower values. Scan mode did not influence the detection. CONCLUSION: Both protocols of micro-CT tested presented an overall satisfactory performance in detecting proximal caries lesions; however, for the depth classification, the method was not accurate.

The fundaments of CBCT and its use for evaluation of paranasal sinuses: review of literature

Image methods such as Magnetic Resonance Imaging (MRI), Computed Tomography (CT) and Cone Beam Computed Tomography (CBCT) are powerful tools to help clinicians on diagnosis and preoperative planning. They provide an accurate view of regional anatomy, anatomical variations and the presence of diseases. Compared to CT, CBCT produces images with adequate spatial resolution with smaller fields of view at lower radiation doses. It has emerged as a potential alternative for obtaining 3D evaluation of the paranasal sinus at relatively modest costs. The aim of this review was to verify whether CBCT images offer an additional value to the evaluation of paranasal sinus

Effects of different surface treatments on bond strength of an indirect composite to bovine dentin.

BACKGROUND: Several surface treatments could be used to improve the bond strength (BS) between indirect composites and cement. AIM: To evaluate the BS of an indirect composite submitted to different surface treatments, cemented to bovine dentin. SETTINGS AND DESIGN: One hundred and fifty conical cavities were prepared in slices of bovine dentin and bulk filled with the composite. MATERIALS AND METHODS: After curing and removal from the cavity, the restorations were treated according to the groups (n = 10): C-untreated, S-Sandblasting; SS-Sandblasting + silane; F-hydrofluoric acid; FS-hydrofluoric acid + silane; SF-Sandblasting + hydrofluoric acid; SFS-Sandblasting + hydrofluoric acid + silane; E-ethanol; ES-ethanol + silane; SE-Sandblasting + ethanol; SES-Sandblasting + ethanol + silane; P-H2O2; PS-H2O2 + silane; SP-Sandblasting + H2O2; SPS-Sandblasting + H2O2 + silane. After cementation, push-out test was performed in a universal testing machine. STATISTICAL ANALYSIS: Data were submitted to nonparametric tests (Kruskal-Wallis and Mann-Whitney U-tests, α = 0.05). The failure mode was observed under a stereomicroscope and the topography by scanning electronic microscopy (SEM). RESULTS: Sandblasted groups led to the highest BS values, (P < 0.001), except for the SFS group. SE, SES, and SPS led to higher BS values than S and SS groups (P < 0.05). F, E and P groups showed the lowest BS values. The number of cohesive or mixed failures was related to higher BS values. SEM evaluation showed major irregularities only for sandblasted groups. CONCLUSIONS: Sandblasting was a safe surface treatment for the indirect composite, increasing the BS values. Hydrofluoric acid applied after sandblasting damaged the BS values and should not be recommended while ethanol and H2O2, when applied after sandblasting, were effective in increasing BS values.