Objective: This article presents the results of a retrospective study of the frequency and classification of odontogenic tumors recorded at four centers of diagnostic pathology in Rio de Janeiro, Brazil.
Study Design: All medical records and microscopic slides of odontogenic tumor specimens for the years 1997 to 2007 were retrieved from the files of four services of diagnostic pathology in Rio de Janeiro City. Diagnoses were re-evaluated and the tumors classified according to the latest (2005) World Health Organization Classification of Tumors.
Results: A total of 201 odontogenic tumors were found among 15,758 oral biopsies (1.3%). The frequencies of these tumors at the four centers ranged from 0.5% at the National Cancer Institute to 3.3% in a private laboratory. Chi-square analysis revealed statistically significant differences (p<0.05) between the proportions of odontogenic tumors in the studied centers. Of these, 94.5% were benign and 5.5% were malignant. Keratocystic odontogenic tumor (32.3%) was the most frequent lesion, followed by ameloblastoma (29.8%) and odontoma (18.4%).
Conclusions: Odontogenic tumors are uncommon in Brazil. Different pathology laboratories reported divergent frequencies of odontogenic tumors, which may reflect institutional specializations and the patient populations served.
Key words:Odontogenic tumors, jaw neoplasms, epidemiology, WHO classification.
ObjectiveTo compare the influence of archwire material (NiTi, beta-Ti and stainless steel)
and brackets design (self-ligating and conventional) on the frictional force
resistance.Material and MethodsTwo types of brackets (self-ligating brackets - Smartclip, 3M/Unitek - and
conventional brackets - Gemini, 3M/Unitek) with three (0, 5, and 10 degrees) slot
angulation attached with elastomeric ligatures (TP Orthodontics) were tested. All
brackets were tested with archwire 0.019"x0.025" nickel-titanium, beta-titanium,
and stainless steel (Unitek/3M). The mechanical testing was performed with a
universal testing machine eMIC DL 10000 (eMIC Co, Brazil). The wires were pulled
from the bracket slots at a cross-head speed of 3 mm/min until 2 mm
displacement.ResultsSelf-ligating brackets produced significantly lower friction values compared with
those of conventional brackets. Frictional force resistance values were directly
proportional to the increase in the bracket/ wire angulation. With regard to
conventional brackets, stainless steel wires had the lowest friction force values,
followed by nickel-titanium and beta-titanium ones. With regard to self-ligating
brackets, the nickel-titanium wires had the lowest friction values, significantly
lower than those of other materials.Conclusioneven at different angulations, the self-ligating brackets showed significantly
lower friction force values than the conventional brackets. Combined with
nickel-titanium wires, the self-ligating brackets exhibit much lower friction,
possibly due to the contact between nickel-titanium clips and wires of the same
material.
Objective: To evaluate the esthetic perception of upper dental midline deviation by
laypersons and if adjacent structures influence their judgment. Methods:An album with 12 randomly distributed frontal view photographs of the smile of a
woman with the midline digitally deviated was evaluated by 95 laypersons. The
frontal view smiling photograph was modified to create from 1 mm to 5 mm
deviations in the upper midline to the left side. The photographs were cropped in
two different manners and divided into two groups of six photographs each: group
LCN included the lips, chin, and two-thirds of the nose, and group L included the
lips only. The laypersons performed the rate of each smile using a visual analog
scale (VAS). Wilcoxon test, Student’s t-test and Mann-Whitney test were applied,
adopting a 5% level of significance. Results: Laypersons were able to perceive midline deviations starting at 1 mm.
Statistically significant results (p< 0.05) were found for all
multiple comparisons of the values in photographs of group LCN and for almost all
comparisons in photographs of group L. Comparisons between the photographs of
groups LCN and L showed statistically significant values (p<
0.05) when the deviation was 1 mm. Conclusions:Laypersons were able to perceive the upper dental midline deviations of 1 mm, and
above when the adjacent structures of the smiles were included. Deviations of 2 mm
and above when the lips only were included. The visualization of structures
adjacent to the smile demonstrated influence on the perception of midline
deviation.
Immunohistochemical staining detected higher number of mast cells than histochemistry. The higher number of mast cells observed in inflamed lesions could indicate the participation of these cells in the inflammatory response in odontogenic lesions. The prevalence of degranulated mast cells in the deep region suggests intense activity of these cells, possibly related to growth of cystic lesions.
On the basis of this study, we concluded that bBMP/bOM with or without AM could preserve the ridge showing viable bone formation for future implant placement.
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