Autofluorescence imaging of potentially malignant mucosa lesions.

OBJECTIVE AND STUDY DESIGN: Several noninvasive adjunctive methods have been proposed for identification of potentially malignant mucosa lesions. The VELscope is an optical device for detecting spatial changes in mucosa autofluorescence caused by premalignant lesions in conjunction with an intraoral exam. The aim of our prospective study was to correlate loss of autofluorescence from undiagnosed mucosa lesions with histology. RESULTS: In total 64 patients considered at risk for squamous cell carcinoma (20 had previous OSCC) were included in the study. Regions with fluorescence visualization loss were considered as malignant or dysplastic. All patients underwent biopsy after VELscope examination. In 22 patients (34.4%) a loss of autofluorescence indicating a squamous intraepithelial neoplasia (SIN) or malignant mucosal lesion was detected. The sensitivity of identification of malignant and dysplastic areas with the VELscope was 100% and the specificity was 80.8%, respectively, compared with histology as gold standard. The positive predictive value was 54.5% and the negative predictive value was 100% respectively. CONCLUSION: Evaluation of autofluorescence imaging with VELscope can assist in the identification of malignant and potentially malignant oral lesions from normal mucosa in high-risk patients but does not help discriminating benign lesions from malignant or premalignant mucosal conditions.

Prevalence of pathologic findings in the maxillary sinus in cone-beam computerized tomography.

OBJECTIVE: The aim of this study was to assess the prevalence of pathologic findings in the maxillary sinus by using cone-beam computerized tomography (CBCT). STUDY DESIGN: One thousand twenty-nine consecutive CBCT scans were retrospectively inspected for pathologic findings in the maxillary sinus by 3 observers. Findings were differentiated by mucosal thickening, partial opacification with liquid accumulation, total opacification, and polypoidal mucosal thickening. Position and diameter of the maxillary sinus ostium were assessed. Correlations for pathologic findings and the factors of age and gender were calculated. Patients with clinical manifestations of sinusitis or total opacification in either sinus were reevaluated. RESULTS: A total prevalence for pathologies in the maxillary sinus of 56.3% was found in this study. The most frequent pathology was mucosal thickening. Patients >60 years of age showed significantly more pathologies in the maxillary sinus (P = .02), and male patients showed significantly more pathologies than female patients (P = .01). Clinical signs of sinusitis could be confirmed on CBCT images for all patients. CONCLUSIONS: Pathologies in the maxillary sinus are frequently found in CBCT imaging and have to be treated or followed-up accordingly. CBCT is applicable for diagnosis and treatment planning of clinically present sinusitis.

Evaluation of maxillary sinus anatomy by cone-beam CT prior to sinus floor elevation.

PURPOSE: Surgical complications during sinus floor elevation are frequently caused by septa in the maxillary sinus. In this study, the prevalence of septa was retrospectively determined via three-dimensional imaging to assess the necessity for appropriate imaging prior to sinus floor elevation. MATERIALS AND METHODS: The cone-beam computed tomography scans of 1,029 consecutive patients were evaluated to assess the prevalence of septa, taking into account patient age and sex as well as the number and orientation of septa and their locations. If septa were present, the height was measured and the orientation was determined. RESULTS: Septa were found in 47% of patients and 33.2% of sinuses. There was no statistical difference in prevalence with respect to age, sex, or side. Most patients with septa showed one septum in one sinus (24.6%); 13.7% showed one septum in each sinus. Other combinations (up to three septa per sinus) were found in 8.7% of patients. Septa were most commonly located in the first molar region (256 septa), followed by the second molar region (225 septa), the third molar region (144), second premolar region (136), the first premolar region (44), and the canine region (5). The mean septal height was 11.7 +/- 6.08 mm for septa in a sagittal orientation (n = 206, 25.3%; maximum height of 37 mm) and 7.3 +/- 5.08 mm for those oriented transversely (n = 608, 74.7%; maximum height of 36 mm). The variance was larger for the sagittal orientation group (37.03 mm) than for transversely oriented septa (25.9 mm). CONCLUSION: Septa were found in 47% of the patients in this sample. Appropriate imaging prior to performing sinus surgery seems justified, since complications and the success rate of sinus floor elevation are clearly related to the presence of septa. Int J Oral Maxillofac Implants 2010;25:258-265.

Experimental immediate loading of dental implants in conjunction with grafting procedures.

The aim of this study was to evaluate immediate loading (IL) of dental implants in conjunction with grafting procedures. A total of 107 IL implants were inserted in six mini pigs. Before implant placement, crestal or apical defects were created, which were treated with bone chips, phycogene hydroxyapatite (HA), bovine HA, or bovine HA enhanced with a synthetic peptide. Crestal grafts were stabilized with titanium membranes. All bridges were in function and showed signs of chewing wear after 4-month loading. Three out of 107 implants showed no osseointegration (2.7%). Most of the crestal defects showed incomplete regeneration, due to an infection of the membranes (74.3%) The difference in height between surgical and remaining defect was calculated as defect development, which was 2.3 +/- 2.08 mm for bone chips with an area of regenerated bone of 22.8 +/- 3.34% and 0.7 +/- 2.22 mm for phycogene HA with 11.3 +/- 4.36% regenerated bone. Bovine HA showed an increase of defects 1.3 +/- 2.47 mm with only 7.9 +/- 1.7% bone regeneration. Bovine HA enhanced with a peptide showed a defect development of 1.1 +/- 1.42 mm with an area of regenerated bone of 18.2 +/- 2.38%. In conclusion, local grafting procedures did not disturb the course of osseointegration for immediate loaded implants if primary stability was reached. The regeneration of apical defects was uneventful even with immediate loading. Crestal defects required membrane fixation with a careful flap elevation to avoid membrane exposure and loss of the graft.

Comparison of cone-beam volumetric imaging and combined plain radiographs for localization of the mandibular canal before removal of impacted lower third molars.

OBJECTIVE: The removal of third molars requires information about the relative position of the root tips and the mandibular nerve. The diagnostic value of conventional radiologic procedures using a panoramic radiograph and symmetrical PA cephalometric radiograph (PAN&PA) was compared with that of a cone-beam volumetric imaging (CBVI) device (Galileos; Sirona, Bensheim, Germany). STUDY DESIGN: Six observers evaluated 30 PAN&PA and 30 CBVI for the position of root tips. Diagnostic information was rated from 1 to 5 (excellent to poor). RESULTS: With PAN&PA, 3 times more scans showed nondetectable information for horizontal position compared with CBVI. The diagnostic information in the vertical dimension received a median rating of 2 (good) for CBVI and for PAN & PA; for the horizontal dimension, CBVI received a median rating of 2 (good), compared with a significantly worse median rating of 3 (sufficient) for PAN & PA (P = .000). The variance was highest for the horizontal dimension with PAN & PA (1.27). CONCLUSION: These findings indicate that cone-beam technology improves the localization of third molar for presurgical planning.

Recent advances in atomic-scale spin-polarized scanning tunneling microscopy.

The Mn3N2 (010) surface has been studied using spin-polarized scanning tunneling microscopy at the atomic scale. The principle objective of this work is to elucidate the properties and potential of this technique to measure atomic-scale magnetic structures. The experimental approach involves the use of a combined molecular beam epitaxy/scanning tunneling microscopy system that allows the study of atomically clean magnetic surfaces. Several key findings have been obtained. First, both magnetic and non-magnetic atomic-scale information has been obtained in a single spin-polarized image. Magnetic modulation of the height profile having an antiferromagnetic super-period of c = 12.14 A (6 atomic rows) together with a non-magnetic superstructure having a period of c/2 = 6.07 A (3 atomic rows) was observed. Methods of separation of magnetic and non-magnetic profiles are presented. Second, bias voltage-dependent spin-polarized images show a reversal of the magnetic modulation at a particular voltage. This reversal is clearly due to a change in the sign of the magnetic term in the tunnel current. Since this term depends on both the tip's as well as the sample's magnetic local density of states, the reversal can be caused by either the sample or the tip. Third, the shape of the line profile was found to vary with the bias voltage, which is related to the energy-dependent spin contribution from the 2 chemically inequivalent Mn sites on the surface. Overall, the results shown here expand the application of the method of spin-polarized scanning tunneling microscopy to measure atomic-scale magnetic structures.

Quantitative evaluation of the fibrin clot extension on different implant surfaces: an in vitro study.

The aim of the present study was a quantitative evaluation of the in vitro fibrin clot extension on different implant surfaces. Forty-five disk-shaped commercially pure Grade 2 titanium samples with three different surface topographies (machined, DPS, and Plus) were used in the present study. For the quantitative evaluation of the fibrin clot, 30 specimens were used (10 per group); human whole blood was employed. Venous blood was drawn from three healthy adult volunteers, and 0.2 mL were immediately dropped onto the surface of each specimen. Contact time was 5 min at room temperature; then the samples were rinsed with saline solution and fixed in a buffered solution of glutaraldehyde and paraformaldehyde. Samples were washed again with buffer and dehydrated in an ascending alcohol series. Specimens belonging to all groups were observed under SEM at a magnification of 1000x. From each sample, 50 random micrographs were collected in .tif format with an N x M 1024 x 768 grid of pixels. Quantitative analysis of fibrin clot extension showed the following results: in machined samples fibrin clot extension was 345987.2 +/- 63747.7 pixels(2) (mean +/- SD), in DPS samples fibrin clot extension was 375930.9 +/- 54726.86 pixels(2) (mean +/- SD), and in Plus samples, fibrin clot extension was 612333.6 +/- 46268.42 pixels(2) (mean +/- SD). With ANOVA it was possible to find that there were significant differences among the groups. The Tukey test revealed that the extension of the fibrin clot of Plus samples was statistically higher compared to both machined and DPS samples. The results of this in vitro study indicate that there is a correlation between implant surface morphology and fibrin clot extension. Improvement in surface microtexture complexity seems to determine the formation of a more extensive and three dimensionally complex fibrin scaffold. Further investigations are necessary to explain in more detail the mechanisms that regulate the fibrin clot formation on different implant surfaces.