Publicações

Blood contamination effect on shear bond strength of an orthodontic hydrophilic resin.

Cunha Tde M, Behrens BA, Nascimento D, Retamoso LB, Lon LF, Tanaka O, Guariza Filho O. OBJECTIVE: The aim of this study was to assess the impact of blood contamination on shear bond strength (SBS) and bond failure pattern of metallic brackets bonded using a new hydrophilic resin. MATERIAL AND METHODS: Eighty human premolars were randomly allocated into 4 groups (n=20) according to the bonding material and contamination pattern. GI: brackets bonded with the Transbond XT conventional system without contamination; GII: brackets bonded with the Transbond XT conventional system with blood contamination; GIII: brackets bonded with the Transbond Self Etching Primer and Transbond Plus Color without contamination; GIV: brackets bonded with the Transbond Self Etching Primer and Transbond Plus Color with blood contamination. The specimens were stored in distilled water at 37°C for 24 h and then submitted to SBS test at a crosshead speed of 0.5 mm/min. After bond failure, the enamel surfaces were observed under an optical microscope at 40x magnification. RESULTS: Blood contamination decreased (P<0.05) shear bond strength when both the hydrophobic (GII) and the hydrophilic resin (GIV) were used. However, the bond strength of Transbond Color Change group was significantly higher (P<0.05) than that of the Transbond XT conventional system group under blood contamination condition. Under dry conditions no difference was observed between the hydrophobic and hydrophilic resin groups. Regarding the bond failure pattern, when blood contaminated the enamel, the adhesive remnant index (ARI) showed predominance of scores 0 and 1, which indicates low adhesion to enamel. CONCLUSIONS: Although there was a significant decrease in the shear bond strength for both adhesive systems under blood contamination, the hydrophilic system showed significantly higher bond strength than the hydrophobic resin adhesive. Therefore, it is advisable to use the hydrophilic resin under risk of blood contamination.

Implant rehabilitation of canines in case of bilaterally missing maxillary lateral incisors.

Bizetto MS, Tessarollo FR, Jimenez EE, Guariza-Filho O, Camargo ES, Tanaka OM. This article reports the successful treatment of a patient with a malocclusion and missing maxillary lateral incisors with an unusual implant-prosthetic rehabilitation in place of the canines. A man, 25 years 5 months of age, was referred by his general dentist with the chief complaint of retained maxillary deciduous canines. He had a skeletal Class I and an Angle Class I malocclusion with an open-bite tendency and prolonged retention of both deciduous canines. The malocclusion was treated with extraction of the maxillary deciduous canines, a fixed edgewise appliance, and implant-prosthesis rehabilitation in place of the canines. A functional and an esthetic occlusion was achieved.

Glossectomy as an adjunct to correct an open-bite malocclusion with shortened maxillary central incisor roots.

Tanaka OM, Guariza-Filho O, Carlini JL, Oliveira DD, Pithon MM, Camargo ES. A young man, 19 years of age, with the chief complaint of an anterior open bite, came for orthodontic treatment with a skeletal Class I relationship, anterior open bite, shortened maxillary incisor roots, and relative macroglossia. The malocclusion was treated by extracting the maxillary first premolars and using a fixed edgewise appliance. A partial glossectomy was performed before the orthognathic surgery with a 3-piece segmental LeFort I mandibular setback, and advancement was achieved with a reduction genioplasty. A functional and esthetic occlusion with an improved facial profile was established, and the apex of the maxillary left central incisor became slightly rounded after prolonged and significant tooth movement. Four years after treatment, there was occlusal stability of the results, and no further root shortening was observed.

Bone stress and strain after use of a miniplate for molar protraction and uprighting: a 3-dimensional finite element analysis.

Largura LZ, Argenta MA, Sakima MT, Camargo ES, Guariza-Filho O, Tanaka OM. INTRODUCTION: The aim of this study was to use the finite element method to evaluate the distribution of stresses and strains on the local bone tissue adjacent to the miniplate used for anchorage of orthodontic forces. METHODS: A 3-dimensional model composed of a hemimandible and teeth was constructed using dental computed tomographic images, in which we assembled a miniplate with fixation screws. The uprighting and mesial movements of the mandibular second molar that was anchored with the miniplate were simulated. The miniplate was loaded with horizontal forces of 2, 5, and 15 N. A moment of 11.77 N·mm was also applied. The stress and strain distributions were analyzed, and their correlations with the bone remodeling criteria and miniplate stability were assessed. RESULTS: When orthodontic loads were applied, peak bone strain remained within the range of bone homeostasis (100-1500 μ strain) with a balance between bone formation and resorption. The maximum deformation was found to be 1035 μ strain with a force of 5 N. At a force of 15 N, bone resorption was observed in the region of the screws. CONCLUSIONS: We observed more stress concentration around the screws than in the cancellous bone. The levels of stress and strain increased when the force was increased but remained within physiologic levels. The anchorage system of miniplate and screws could withstand the orthodontic forces, which did not affect the stability of the miniplate.

Effect of fluoxetine on induced tooth movement in rats.

Franzon Frigotto GC, Miranda de Araujo C, Guariza Filho O, Tanaka OM, Batista Rodrigues Johann AC, Camargoa ES. INTRODUCTION: Fluoxetine is a widely used antidepressant. Its various effects on bone mineral density are well described. The aim of this study was to evaluate the effect of fluoxetine on induced tooth movement. METHODS: Seventy-two Wistar rats were divided into 3 groups: M (n = 24; 0.9% saline solution and induced tooth movement), FM (n = 24; fluoxetine, 10 mg/kg, and induced tooth movement), and F (n = 24; fluoxetine, 10 mg/kg only). After 30 days of daily saline solution or fluoxetine administration, an orthodontic appliance (30 cN) was used to displace the first molar mesially in groups M and FM. The animals were killed 3, 7, and 14 days after placement of the orthodontic appliances. The animals in group F did not receive induced tooth movement but were killed at the same times. We evaluated tooth movement rates, collagen neoformation rates by polarization microscopy, numbers of osteoclast by tartrate-resistant acid phosphatase, and trabecular bone modeling by microcomputed tomography of the femur. RESULTS: The tooth movement rates were similar in groups M and FM at all studied time points (P >0.05). The rate of newly formed collagen had a reverse pattern in groups M and FM, but the difference was not statistically significant (P >0.05). There were significantly more osteoclasts in group FM than in group F on day 3 (P <0.01). The trabecular spacing was significantly larger in group F compared with group M on day 14 (P <0.05). CONCLUSIONS: Fluoxetine did not interfere with induced tooth movement or trabecular bone in rats.

Effect of organic solvents and ultrasound on the removal of orthodontic brackets.

Santana RM, Rached RN, Souza EM, Guariza-Filho O, Camargo ES, Pithon MM, Tanaka OM. OBJECTIVE: To evaluate the effect of organic gel solvents (70% acetone and 90% ethanol) and ultrasound in the removal of metallic brackets. MATERIALS AND METHODS: Metallic brackets were bonded with light-cured orthodontic composite (Transbond XT) in 120 human bicuspids and divided into 6 groups for the enamel etch-and-rinse adhesive system (XT) and 6 groups to self-etching system (SEPT) according to pretreatment to removal test: control, 70% acetone, 90% ethanol, ultrasound, 70% acetone+ultrasound, and 90% ethanol+ultrasound. The brackets were subjected to removal by shear testing and Adhesive Remnant Index (ARI) evaluation. Some specimens were prepared and its adhesive interface and etching ability observed by scanning electron microscopy (SEM). RESULTS: Only the factor 'ultrasound' and its interaction with 'adhesive' were detected as a source of variance, with the SEPT/ultrasound showing the lowest shear strength than the other groups. Regardless the factor 'ultrasound', XT showed a higher ARI than SEPT; however, when the solvents were used, no differences were detected between XT and SEPT. CONCLUSION: The organic solvents were not effective in reducing shear bond strength. The etch-and-rinse adhesive system showed a higher and more favorable ARI score than the self-etching primer. The behavior of the organic solvents on ARI showed to be better when associated with the self-etching primer. The ultrasound was effective in reducing the shear bond strength of the self-etching adhesive system but not in affecting the ARI of the adhesive systems.

Optimizing Esthetics and Function in a Case of Moderate Reduced Bone Support.

Sabatoski CV, Guariza Filho O, Camargo ES, Lacerda-Santos R, Tanaka OM. The aim of this article is to report the orthodontic treatment of a woman aged 53 years 6 months whose chief complaint involved her facial esthetics and crowding. She presented a moderate reduction in bone support, but no periodontal disease, over the past 15 years. The maxillary left first premolar and both mandibular first premolars were extracted. The dental protrusion was reduced and all the spaces were closed, resulting in a significant improvement in facial esthetics. After 16 months, the satisfactory results in terms of the functional position of the teeth were maintained with the bone level remaining unchanged.

Tissue responses resulting from tooth movement surgically assisted by corticotomy and corticision in rats.

Peron AP, Johann AC, Papalexiou V, Tanaka OM, Guariza-Filho O, Ignácio SA, Camargo ES. OBJECTIVE: To compare the histological responses in corticotomy- and corticision-assisted tooth movement. MATERIALS AND METHODS: Ninety Wistar rats were divided into three groups: C (control-tooth movement only), CT (tooth movement + corticotomy), and CI (tooth movement + corticision). Surgeries were performed on the vestibular and lingual cortical bone of the maxillary first molar. Tooth movement was carried out with nickel-titanium closed coil springs having a force of 30 g. The rats were sacrificed at 3, 14, and 28 days. To evaluate the number of osteoclasts and amount of root resorption, a tartrate-resistant acid phosphatase stain was used. Hematoxylin and eosin staining was performed for areas of hyalinization, and the organic bone matrix was stained with picrosirius. RESULTS: The CT group showed a greater number of osteoclasts than did the C group on day 3 (P < .05). At the same time point, the CT and CI groups showed a delayed onset of organic bone matrix remodeling and a lower incidence of root resorption than did the C group (P < .05). There were also fewer hyalinization areas in the CI group than in the C group on day 3 (P < .05). CONCLUSIONS: Corticotomy effectively increased bone resorption during the early stages of tooth movement, but this increase was not observed for corticision. The surgical procedures did not accelerate organic bone matrix remodeling. Corticotomies and corticisions decreased the risk of root resorption only during the early stages of movement. Corticision reduced the level of hyalinization, while corticotomy did not.

The effect of potassium diclofenac and dexamethasone on MMP-1 gene transcript levels during experimental tooth movement in rats.

Molina Da Silva GP, Tanaka OM, Campos Navarro DF, Repeke CE, Garlet GP, Guariza-Filho O, Trevilatto PC. OBJECTIVES: The aim of this study was to analyze MMP-1 transcript levels in periodontal tissues of rats that underwent orthodontic treatment using potassium diclofenac and dexamethasone at different stages of tooth movement. SETTING AND SAMPLE POPULATION: The sample comprised of ninety male Wistar rats. MATERIAL AND METHODS: A closed nickel-titanium coil spring was used to apply a force of 50 cN to move the maxillary right first molars mesially. One group received daily doses of 0.9% saline solution, the second group received daily doses of 5 mg/kg potassium diclofenac, and the third group received daily doses of 0.5 mg/kg dexamethasone. Tooth movement was observed on days 0, 1, 3, 7, and 14. MMP-1 transcript levels were evaluated by real-time polymerase chain reaction and the results were compared between groups by three-way ANOVA, with a significance level of 0.05. RESULTS: Transcript levels increased in groups that received the coil spring treatment on all days of the experiment. MMP-1 expression was found to be decreased in groups treated with potassium diclofenac and dexamethasone compared to that in the control group, on days 1, 3, 5, and 7. CONCLUSIONS: The application of orthodontic forces significantly increased MMP-1 transcript levels. The use of anti-inflammatory drugs may have an inhibitory effect on MMP-1 expression.

Prosthetic, orthodontic and implant-supported rehabilitation of five maxillary anterior teeth with alveolar bone loss.

Guariza-Filho, Araujo CM, Schroder AGD, Tanaka OM, Kern R, Ruellas AC. INTRODUCTION: Treatment of maxillofacial injuries is complex and requires the establishment of a comprehensive and accurate diagnosis and correct treatment planning. OBJECTIVE: The objective of this case report was to describe the re-treatment of a 27-year-old woman who was involved in a severe car accident that resulted in the loss of five anterior teeth and alveolar bone, and whose previous orthodontic and surgical treatments had been unsuccessful. CASE REPORT: In this case, the space for the missing mandibular molar was reopened to allow for rehabilitation. The positions of the mandibular incisors were improved. The right mandibular canine was moved to the mesial, allowing for correction of the Class II canine relationship on that side, and implants were placed to replace the maxillary anterior teeth. CONCLUSION: Anterior aesthetic and functional rehabilitation using a multidisciplinary approach was essential to improve the patient's facial aesthetics, to obtain great improvement in function and to achieve occlusal stability after 2 years of follow-up.
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