Lucas Cavalieri-Pereira

Bacterial adhesion and colonization differences between zirconia and titanium implant abutments: an in vivo human study

Purpose Several parameters have been described for determining the success or failure of dental implants. The surface properties of transgingival implant components have had a great impact on the long-term success of dental implants. The purpose of this study was to compare the tendency of two periodontal pathogens to adhere to and colonize zirconia abutments and titanium alloys both in hard surfaces and soft tissues. Methods Twelve patients participated in this study. Three months after implant placement, the abutments were connected. Five weeks following the abutment connections, the abutments were removed, probing depth measurements were recorded, and gingival biopsies were performed. The abutments and gingival biopsies taken from the buccal gingiva were analyzed using real-time polymerase chain reaction to compare the DNA copy numbers of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and total bacteria. The surface free energy of the abutments was calculated using the sessile water drop method before replacement. Data analyses used the Mann Whitney U-test, and P-values below 0.05 find statistical significance. Results The present study showed no statistically significant differences between the DNA copy numbers of A. actinomycetemcomitans, P. gingivalis, and total bacteria for both the titanium and zirconia abutments and the biopsies taken from their buccal gingiva. The differences between the free surface energy of the abutments had no influence on the microbiological findings. Conclusions Zirconia surfaces have comparable properties to titanium alloy surfaces and may be suitable and safe materials for the long-term success of dental implants.

Maxillary Sinus Floor Augmentation Using Blood Without Graft Material. Preliminary Results in 10 Patients

PURPOSE The maxillary sinus lift is recognized and stable, and there have been different innovations to optimize the technique. The aim of this study was to investigate the maxillary sinus lift technique with the use of a blood clot and without the use of a bone graft. MATERIALS AND METHODS Ten patients were recruited for a unilateral sinus lift; patients without sinus pathology or other contraindication were selected. The maxillary sinus was accessed conventionally under local anesthesia followed by an osteotomy and a 1-cm(2) bony window access. The sinus membrane was detached and the window was repositioned above and stabilized with a 12- or 14-mm osteosynthesis screw introduced through the alveolar ridge. Dental implants were installed in the second surgical stage. Standardized panoramic radiographic checks were performed at every stage. RESULTS Seven completely edentulous patients and 3 partially dentate patients were treated surgically. From the first to the second surgery, a bone gain of 2.37 mm was obtained, although loss of bone height was observed in 1 completely edentulous patient. In 7 patients, it was not possible to install the implants owing to insufficient bone height or inadequate bone quality. CONCLUSION The protocol used in this investigation failed in the bone increase required for implant installation.

Análisis Topográfico de la Superfície de Implantes de Titanio Comercialmente Puro a Través de Microscopía Electrónica de Barrido

Este trabajo tiene como objetivo analizar topograficamente la superficie de implantes de titanio comer-cialmente puros. Fueron seleccionados ocho implantes de las siguientes fabricantes: Conexao - Sistema de Proteses; Lifecore - Biomedical; AS Technology y S - Serson Internacional. Las muestras presentaban tratamiento de la superficies, a traves de las tecnicas de ataque acido (Conexao) y plasma spray de titanio (Lifecore-Biomedical; AS Technology y S -Serson International), siendo divididas en cuatro grupos, conteniendo dos implantes del mismo lote de cada fabricante. Los analisis fueron realizados a traves de microscopia electronica de barredura (MEB). Los estudios a traves de MEB revelaron la topografia rugosa de la superficie y la uniformidad de las areas entre las roscas de los implantes. Se puede concluir que todas las muestras presentaron rugosidad en la superficie, con diferencias en la micromorfologia entre todos los implantes.

Uso de Guía de Metil-metacrilato Fabricados en Biomodelo de Poliuretano para el Tratamiento Tardío de Fractura Panfacial

RESUMEN: El manejo de las secuelas faciales por fracturas no tratadas ha tenido un crecimiento importante debidoal uso de los biomodelos. Estos permiten optimizar la cirug™a, disminuir los tiempos quirœrgicos y mejorar los resultados. Elpresente articulo muestra un caso de secuela de fractura facial tratada con osteotom™as con ayuda de gu™as quirœrgicosfabricados en base a un biomodelo operado; se presenta el resultado postoperatorio de 6 meses con una resoluciSnadecuada.˚ PALABRAS CLAVE: fractura panfacial, secuela facial, biomodelo. INTRODUCCIiN ˚˚El tratamiento de las fracturas panfaciales esuna patolog™a altamente compleja y aun mas cuandoes realizado de forma tard™a (He et al. , 2007). Pacien-tes con secuelas de trauma facial normalmente pre-sentan alteraciSn de la oclusiSn, ensanchamiento fa-cial, enoftalmo traum⁄tico, distopia, entre otros; estassecuelas de trauma presentan generalmente mal uniSnSsea˚ y contracciSn cicatricial de diferentes tejidos.˚Basados en t”cnicas para preservar la funciSny la est”tica facial, existen muchas formas de realizarel tratamiento quirœrgico, direccionando el procedimien-to desde inferior a superior y viceversa, siendo ade-m⁄s centrifuga o centr™peta (Kelly, 1978; Gruss &Phillips, 1989). Algunos autores han sugerido que lareconstrucciSn facial deber™a comenzar por la mand™-bula para devolver ancho y proyecciSn sagital del ter-cio inferior (Wenig, 1991) y cuando existe fracturatransversal de maxila, se deber™a comenzar por estafractura para guiar la reconstrucciSn mandibular (Kelly

Resistance of four fixation techniques used to treat subcondylar fractures

ObjectiveThis study aimed to evaluate the resistance of four fixation techniques used to treat subcondylar fractures. The following techniques were evaluated: fixation with one 4-hole single straight plate; fixation with one 2-mm 4-hole system plate and one 1.5-mm 3-hole system plate; fixation with two 2-mm plates with a 3-hole anterior plate; and fixation with two 2-mm plates with four holes each.Study designEach fixation technique was subjected to a resistance test. The load values were measured when displacement of 1, 2, and 5 mm was reached. Load values were compared for statistically significant differences using analysis of variance (ANOVA; p < 0.5) and Tukey’s test.ResultsStatistically significant differences were observed, when the load was applied to the first molar on the side of the fracture. The group treated with a 4-hole, 2-mm, one plate system showed resistance to lower load values than the groups treated with two plates in any combination.ConclusionsWhen the fracture was fixed using two plates, regardless of the kind of plates used, no statistically significant difference between the groups was observed. However, two plate systems showed better resistance than one plate systems.

Mechanical stability of 2-plate versus 4-plate osteosynthesis in advancement Le Fort I osteotomy. An in vitro study

INTRODUCTION Stability in orthognathic surgery is nowadays considered as efficient and adequate. The objective of this study was to determine and to compare the mechanical resistance to vertical load of a Le Fort I advancement osteotomy stabilized by mean of two different osteosynthesis techniques, one using two 10-hole pre-bent T-shaped plates, the other using four manually bent 4-hole L- and J-shaped plates. MATERIEL AND METHODS Standardized Le Fort I advancement osteotomies have been made on polyurethane models. The maxillary advancement was 5mm. Two groups of five models each were created. Group 1 was stabilized by mean of two 10-hole pre-bent T-shaped plates fixed by monocortical screws in the paranasal region. Group 2 was stabilized by mean of manually bent four 4-hole L-shaped plates fixed monocortical screws in the zygomatic and paranasal regions. A testing machine was used to load vertically the models at the range of 1mm/min linear displacement until peak load and system failure. Statistical analysis was realized using ANOVA and t-test, considering P as significant if <0.005. RESULTS The maximal tolerated load was 15N in group 1and 42.71N in group 2 (P=0.003). DISCUSSION The use of two T-shaped 10-holes pre-bent plates allows for less resistance in vertical loading than the use of four 4-holes manually bent L-shaped plates.