Osteossarcoma em maxila: relato de caso

ResumoO osteossarcoma é a neoplasia maligna mais comum do osso, ocorrendo com maior frequência nos ossos longos; nos maxilares é uma lesão rara. Os sintomas mais frequentes são o aumento de volume local, dor intensa e limitação funcional. O tratamento atual do osteossarcoma consiste em ressecção cirúrgica associada ou não à radioterapia e/ou quimioterapia. O objetivo deste trabalho é apresentar um caso de osteossarcoma no maxilar de um paciente de 24 anos do género masculino, abrangendo o palato duro, estendendo-se até o palato mole, com evolução de 6 meses. O diagnóstico foi estabelecido por achados clínicos, imagiológicos e histopatológicos. O paciente foi submetido a quimioterapia, mas faleceu passados 6 meses com o aparecimento de metástases.AbstractOsteosarcoma is the most common malignancy of bone, occurring more frequently in long bones, being rare in jaws. The most common symptoms are swelling, local pain and functional limitation; current treatment of osteosarcoma consists of surgical resection and additional chemotherapy. The objective of this work is to present a case of osteosarcoma of the maxilla of a patient 24 years old with a tumor involving the hard palate, extending to the soft palate, with an evolution of six months. The diagnosis was established by clinical, imaging and histopathology. The patient was subject to chemoterapy but died after 6 months with metastases

Comparison of static friction with self-ligating, modified slot design and conventional brackets

OBJECTIVE: To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters. MATERIAL AND METHODS: The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClipTM, 3M/Unitek, Monrovia, USA), with a modified slot design (Mini Uni TwinTM, 3M/Unitek, Monrovia, USA) and conventional (Kirium, Abzil, São José do Rio Preto, Brazil). The samples were mounted in a testing device with three different angulations and tested with 0.014" and 0.018" stainless steel wires (American Orthodontics, Sheboygan, USA). The static frictional force was measured using a universal testing machine (DL 500, EMIC®, São José dos Pinhais, Brazil) with a crosshead speed of 1 mm/min. Statistical analysis was performed by two-way ANOVA followed by Bonferroni's post hoc test. RESULTS: There was a significant difference (

Ossifying odontogenic fibroma: a rare case report

Odontogenic fibroma (OF) is a rare benign odontogenic neoplasm that is most commonly found in the mandibular/ premolar region of female patients in the second to fourth decades of life. Well-defined radiolucent lesions that may induce root resorption are normally observed. Rare variants of OF have been described in the prior literature, including references to: 1) giant cell lesions, 2) amyloid-like protein deposition, and 3) ossifying variants. Immuno - histochemistry can contribute to understanding the biological behavior and the pathogenesis of OF. Therefore, this case report aimed to describe a new case of ossifying OF and discuss the histopathology and immunohistochemical features

Evaluation of three different rotary systems during endodontic retreatment: analysis by scanning electron microscopy

Background: Endodontic therapy is considered a series of important and interdependent steps, and failure of any of these steps may compromise the treatment outcome. This study aimed to evaluate the effectiveness of three different rotary systems in removing obturation materials during endodontic retreatment using scanning electron microscopy (SEM) analysis. Material and Methods: Thirty-six endodontically treated teeth were selected and divided into 3 groups of 10 and 1 control group with 6 dental elements. The groups were divided according to the rotary system used for removing gutta-percha, as follows: G1: ProTaper system; G2: K3 system; G3: Mtwo system; and G4: Control group. Thereafter, the roots were split and the sections were observed under SEM, for analysis and counting of clear dentinal tubules, creating the variable “degree of dentinal tubule patency” (0: intensely clear; 1: moderately clear; 2: slightly clear; 3: completely blocked). The data were subjected to the Friedman and Kruskal-Wallis statistical tests. Results: No differences were observed in the “degree of dentinal tubule patency” neither between the root thirds (to each evaluated group) nor between the groups (to each evaluated third). Nevertheless, when the three root thirds were grouped (providing evaluation of all root extension), the “degree of dentinal tubule patency” was lower in G1 than in G3 ( p <0.05), but showed no differences neither between G1 and G2 nor G2 and G3. Conclusions: No technique was able to completely remove the canal obturation material, despite G1 having shown better results, although without significant difference to G

Importance of rotary systems in dental care by undergraduate students in patients of a public health service of Belo Horizonte

Background: The aim of this study was to evaluate the fracture rates of ProTaper rotary files used in the endodontics extension clinic of the Undergraduate Dentistry Course of the Pontifical Catholic University of Minas Gerais during the prior eight years. Material and Methods: Control record data regarding file usage by students were collected and analyzed by semester. For each period, the total number of patient consultations, the frequency of file use, the occurrence of fractures and the file numbers for which fractures occurred were noted. Descriptive statistics, including frequency of file fractures were calculated for all file types. The chi-square test was used to evaluate differences in the frequency of file fractures between all file types. Results: The study results revealed that during the examined period, there were 1006 consultations and 7993 uses of files. A total of 30 file fractures were recorded throughout this period; thus, fractures occurred in 0.37% of total file uses and 2.98% of all consultations. The most frequently used files were S1, S2 and F1, and these files also accounted for the most fractures. However, no differences in the frequency of file fractures were observed between the file types ( p >0.05). Conclusions: The low fracture rates observed in this study indicate that the examined instruments can be used to safely provide dental care to patients

Physical and chemical properties of orthodontic brackets after 12 and 24 months: in situ study

Objective: The aim of this article was to assess how intraoral biodegradation influenced the surface characteristics and friction levels of metallic brackets used during 12 and 24 months of orthodontic treatment and also to compare the static friction generated in these brackets with four different methods of the ligation of orthodontic wires. Material and Methods: Seventy premolar brackets as received from the manufacturer and 224 brackets that were used in previous orthodontic treatments were evaluated in this experiment. The surface morphology and the composition of the deposits found in the brackets were evaluated with rugosimetry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Friction was analyzed by applying tensile tests simulating sliding mechanics with a 0.019x0.025" steel wire. The static friction levels produced by the following ligation methods were evaluated: loosely attached steel ligature around all four bracket wings, steel ligature attached to only two wings, conventional elastomeric ligation around all 4 bracket wings, and non-conventional Slide® elastomeric ligature. Results: The results demonstrated the presence of biodegradation effects such as corrosion pits, plastic deformation, cracks, and material deposits. The main chemical elements found on these deposits were Carbon and Oxygen. The maximum friction produced by each ligation method changed according to the time of intraoral use. The steel ligature loosely attached to all four bracket wings produced the lowest friction levels in the new brackets. The conventional elastic ligatures generated the highest friction levels. The metallic brackets underwent significant degradation during orthodontic treatment, showing an increase in surface roughness and the deposit of chemical elements on the surface. Conclusion: The levels of static friction decreased with use. The non-conventional elastic ligatures were the best alternative to reduce friction

Stromal myofibroblasts in oral leukoplakia and oral squamous cell carcinoma

Objectives: Oral leukoplakia (OL) is the main potentially malignant disorder and oral squamous cell carcinoma (OSCC) is the most common malignancy of the oral mucosa. Stromal myofibroblasts play an important role in tumor invasion and metastasis, due to its ability to modify the extracellular matrix. This study aimed to evaluate the presence of stromal myofibroblasts in OL and OSCC. Differences in the presence of myofibroblasts among OL with distinct grades of epithelial dysplasia as well as between histologically high- and low-invasive OSCC were also assessed. Study D esign: A total of 30 OL and 41 OSCC from archival formalin-fixed, paraffin-embedded specimens were evaluated. 10 samples of normal oral mucosa were used as a control. Myofibroblasts were identified by immunohistochemical detection of alpha smooth muscle actin and its presence was classified as negative, scanty or abundant. Differences in the presence of myofibroblasts among OL with distinct grades of epithelial dysplasia as well as between high- and low-invasive OSCC were analyzed using the Mann-Whitney test. Results: Myofibroblasts were not detected in normal oral mucosa and OL, whatever its histological grade. In OSCC, the presence of stromal myofibroblasts was classified as negative in 11 (26.8%), scanty in 15 (36.6%), and abundant in 15 samples (36.6%). The presence of stromal myofibroblasts was statistically higher in high-invasive OSCC than in low-invasive OSCC (p<0.05). Conclusions: Stromal myofibroblasts were not detected in OL, indicating that these cells are not important during oral carcinogenesis. Nevertheless, stromal myofibroblasts were heterogeneously detected in OSCC and its presence was higher in tumors with a more diffuse histological pattern of invasion. These findings suggest that myofibroblasts are associated with the creation of a permissive environment for tumor invasion in OSC

Root canal shaping of curved canals by Reciproc Blue system and Pro Taper Gold : a micro-computed tomographic study

This study aimed to evaluate the centralization and transportation of ProTaper Gold (PTG) rotary system and Reciproc Blue (RB) reciprocating system in curved canals, by using micro-CT. Twenty extracted mandibular molars were previously scanned by usin

Mechanical Properties of Mini-Implants Used in Extra-Radicular Anchorage

Objective:&nbsp;To evaluate the mechanical properties of mini-implants (MIs) manufactured from stainless steel and compare them with conventional titanium-aluminum-vanadium alloy MIs.&nbsp;Material and Methods:&nbsp;The following groups were formed: G1 (n=24), 8×1.5 mm steel MIs; G2 (n=24), 12×2.0 mm steel MIs; and G3 (n=24), 10×1.5 mm titanium MIs. The 72 MIs were inserted in the infra zygomatic crest region of the maxilla and retromolar trigone in the jaw of 10 pigs. Pull-out, insertion torque, fracture and percussion tests were performed in order to measure the tensile strength, primary stability and fracture strength of MIs. A digital torque gauge was used to measure insertion and fracture torque, a universal mechanical testing machine was used for pull-out testing and a periotest device was used to measure the micromovement of MIs. For morphological and MI component evaluation, scanning electron microscopy (SEM) was performed. D\u27Agostino &amp; Pearson, Kruskal-Wallis, and Dunn post-hoc and normality tests were used.&nbsp;Results:G2 insertion and fracture torques were significantly higher than G1 and G3 insertion and fracture torques (p&lt;0.05). The pull-out and percussion tests presented similar values among the groups. SEM revealed that the fracture point was predominantly on the fourth thread for steel MIs (G1 and G2) and on the seventh thread for titanium-aluminum-vanadium MIs (G3).&nbsp;Conclusion:&nbsp;The mechanical properties of stainless steel MIs are superior to those of titanium-aluminum-vanadium alloy MIs

Metallothionein immunoexpression in oral leukoplakia

Objectives: to report the immunoexpression of metallothionein in oral leukoplakia and to correlate with histological grade and clinical localization. Leukoplakia is the most common potentially malignant lesion of the oral cavity. As the histological study of oral leukoplakia can not predict precisely the malignant transformation of this lesion, and metallothionein is a protein that has been associated with carcinogenesis, this study could be auxiliary in this histological assessment of this lesion. Study design: samples of oral leukoplakia (35 cases) and of normal oral mucosa (10 cases) were evaluated. Oral leukoplakia was graded in: hyperkeratosis without dysplasic change (9 cases), mild dysplasia (8 cases), moderated dysplasia (10 cases), and severe dysplasia (8 cases). Immunohistochemistry for the metallothionein was performed and the Mann-Whitney test was used in statistical analysis. Results: metallothionein was identified in squamous cells of the all samples. The metallothionein stain in all cases exhibit a mosaic pattern and was predominantly in compartments cytoplasmatic and nuclear simultaneously. The total stain was significantly higher in moderate dysplasia when compared with normal oral mucosa, hyperkeratosis, and mild dysplasia. Conclusion: it was suggested that the metallothionein may be a marker to moderate dysplasia and may play a role in oral carcinogenesis