Maxillary and mandibular width changes studied using metallic implants.

The purpose of this implant study was to evaluate the transverse stability of the basal maxillary and mandibular structures. The sample included 25 subjects between 12 and 18 years of age who were followed for approximately 2.6 years. Metallic implants were placed bilaterally into the maxillary and mandibular corpora before treatment. Once implant stability had been confirmed, treatment (4 first premolar extractions followed by fixed appliance therapy) was initiated. Changes in the transverse maxillary and mandibular implants were evaluated cephalometrically and two groups (GROW+ and GROW++; selection based on growth changes in facial height and mandibular length) were compared. The GROW++ group showed significant width increases of the posterior maxillary implants (P <.001) and the mandibular implants (P =.009); there was no significant change for the anterior maxillary implants. The GROW+ group showed no significant width changes between the maxillary and mandibular implants. We conclude that (1) there are significant width increases during late adolescence of the basal mandibular and maxillary skeletal structures and (2) the width changes are related with growth potential.

Comparative in vivo study of commercially pure Ti implants with surfaces modified by laser with and without silicate deposition: Biomechanical and scanning electron microscopy analysis

The purpose of this study was to evaluate commercially pure titanium implant surfaces modified by laser beam (LS) and LS associated with sodium silicate (SS) deposition, and compare them with machined surface (MS) and dual acid-etching surfaces (AS) modified. Topographic characterization was performed by scanning electron microscopy-X-ray energy dispersive spectroscopy (SEM-EDX), and by mean roughness measurement before surgery. Thirty rabbits received 60 implants in their right and left tibias. One implant of each surface in each tibia. The implants were removed by reverse torque for vivo biomechanical analysis at 30, 60, and 90 days postoperative. In addition, the surface of the implants removed at 30 days postoperative was analyzed by SEM-EDX. The topographic characterization showed differences between the analyzed surfaces, and the mean roughness values of LS and SS were statistically higher than AS and MS. At 30 days, values removal torque LS and SS groups showed a statistically significant difference (p < 0.05) when compared with MS and AS. At 60 days, groups LS and SS showed statistically significant difference (p < 0.05) when compared with MS. At 90 days, only group SS presented statistically higher (p < 0.05) in comparison with MS. The authors can conclude that physical chemistry properties and topographical of LS and SS implants increases bone-implant interaction and provides higher degree of osseointegration when compared with MS and AS. © 2012 Wiley Periodicals, Inc.

Prototyping for Surgical and Prosthetic Treatment

Techniques of rapid prototyping were introduced in the 1980s in the field of engineering for the fabrication of a solid model based on a computed file. After its introduction in the biomedical field, several applications were raised for the fabrication of models to ease surgical planning and simulation in implantology, neurosurgery, and orthopedics, as well as for the fabrication of maxillofacial prostheses. Hence, the literature has described the evolution of rapid prototyping technique in health care, which allowed easier technique, improved surgical results, and fabrication of maxillofacial prostheses. Accordingly, a literature review on MEDLINE ( PubMed) database was conducted using the keywords rapid prototyping, surgical planning, and maxillofacial prostheses and based on articles published from 1981 to 2010. After reading the titles and abstracts of the articles, 50 studies were selected owing to their correlations with the aim of the current study. Several studies show that the prototypes have been used in different dental-medical areas such as maxillofacial and craniofacial surgery; implantology; neurosurgery; orthopedics; scaffolds of ceramic, polymeric, and metallic materials; and fabrication of personalized maxillofacial prostheses. Therefore, prototyping has been an indispensable tool in several studies and helpful for surgical planning and fabrication of prostheses and implants.

Analysis of mechanical behavior of implant-supported prostheses in the anterior maxilla: analysis by speckle pattern interferometry

The use of implants to rehabilitation of total edentulous, partial edentulous or single tooth is increasing, it is due to the high rate of success that this type of treatment present. The objective of this study was to analyze the mechanical behavior of different positions of two dental implants in a rehabilitation of 4 teeth in the region of maxilla anterior. The groups studied were divided according the positioning of the implants. The Group 1: Internal Hexagonal implant in position of lateral incisors and pontic in region of central incisors; Group 2: Internal Hexagonal implant in position of central incisors and cantilever of the lateral incisors and Group3 - : Internal Hexagonal implants alternate with suspended elements. The Electronic Speckle Pattern Interferometry (ESPI) technique was selected for the mechanical evaluation of the 3 groups performance. The results are shown in interferometric phase maps representing the displacement field of the prosthetic structure.

Osseous regeneration in the presence of fibrin adhesive material (Tissucol) and epsilon-aminocaproic acid (EACA).

The effects of Tissucol and Tissucol/EACA on bone healing were evaluated histologically. Experimental defects were made in both tibias of 25 rats. Test materials were placed in defects in right tibias and left tibias served as control. Five animals in each group were killed at 1, 3, 7, 14 and 21 days after surgery. Results showed that: a) Tissucol did not interfere with connective and osseous tissue formation; b) Tissucol allowed new bone formation; c) Tissue residues in Tissucol groups in sections of 21-day specimens did not impair healing; d) Tissucol/EACA was usually completely resorbed and healing was complete 21 days after surgery in the Tissucol/EACA group.

Naso-orbicular tissue necrosis by Streptococcus parasanguis in a patient with Fanconi anemia: Clinical and laboratory aspects

Fanconi anemia (FA) is a rare autosomal recessive disorder, characterized by pancytopenia and progressive hypoplasia of the bone marrow. A 23-year-old woman with FA showed severe pancytopenia and developed an abscess on the infraorbicular region on the right side of the face that progressed to phlegmon and caused tissue necrosis of the nostrils, nasal septum, nasal fossa, and posterior orbital region. Laboratory examination showed Streptococcus parasanguis as the etiologic agent of the phlegmon. Supportive treatment was recommended due to donor incompatibility for bone marrow transplant. The intraoral examination showed spontaneous gingival bleeding, edema of the interdental papillae, hematomas on the superior and inferior lips, bacterial and fungal infections, and adequate oral hygiene. The patient was treated with the administration of an antibiotic (imipenem), an antifungal (amphotericin B), and mouth washing with antiseptic solutions. Periodontal prophylaxis and orientation to and control of oral hygiene and diet were also used during the remission period. For functional and esthetic rehabilitation of the alar regions and nasal dorsum, an acrylic resin nasal prosthesis was made, supported by a spectacle frame.

Polyethylene gel in the subcutaneous tissue of rats: Histopathologic and systemic evaluation

Purpose: To evaluate the histological and systemic response to subcutaneous injection of polyethylene gel in rats. Methods: Twenty-one white male rats were divided into 3 groups (G): G1 and G2 received subcutaneous polyethylene gel injection in the dorsal midline and were sacrificed at 30 and 60 postoperative days, respectively. G3 was not exposed to the polyethylene gel and was sacrificed after 60 days. Blood levels of lactate dehydrogenase (LDH), creatine kinase (CK), and alkaline phosphatase (ALP) were evaluated. The heart, kidney, liver, adrenal gland, injection site, and adjacent tissues were histologically examined. The results were submitted to statistical analysis. Results: There was no clinical evidence of extrusion, reduction of the injected volume, or abnormalities in the adjacent tissues. Blood levels of CK and LDH were normal and similar in all groups. ALP levels were significantly lower in G2 than in G1 and G3. The systemic organs were normal on histological examination in the 3 groups evaluated. Microscopically, the polyethylene gel was surrounded by a thin pseudocapsule formation and minimal inflammatory cell response, which decreased from G1 to G2. Conclusion: The subcutaneous injection of polyethylene gel in rats elicited minimal local inflammatory response and no systemic side effects. Copyright © 2008 Informa Healthcare USA, Inc.

Extraoral implants in irradiated pacients

The aim of this study is to analyze the success of extraoral osseointegrated implants used to support and contain prosthesis designed to rehabilitate craniofacial deformities.Method: This study was based on the retrospective assessment of charts from 59 patients submitted to cancer surgery and who received 164 extraoral implants to contain facial prosthesis.Results: Among 164 implants, 42 were fixed in previously irradiated regions. Eight of the implants did not have osseointegration; and from these, 2 were fixed in irradiated bone. The result show 116 (95.1%) successfully osseointegrated implants in non-irradiated sites. The success rate among 42 implants fixed in previously irradiated bones was 40 (95.3%) osseointegrated implants.Conclusion: The use of extraoral craniofacial implants represents a safe and effective approach to treat facial deformities as a support for the rehabilitation prosthesis. Radiotherapy treatment does not prevent osseointegration.

The influence of bone quality on the biomechanical behavior of full-arch implant-supported fixed prostheses

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Total Endovascular Debranching of the Aortic Arch

Background: Significant morbidity and mortality are related to conventional aortic replacement surgery. Endovascular debranching techniques, fenestrated or branched endografts are time consuming and costly.Objective: We alternatively propose to use endovascular approach with parallel grafts for debranching of aortic arch.Methods: Under general anesthesia, 12 F sheaths were inserted in the femoral, axillary and common carotid arteries for vascular accesses. ViaBahn grafts 10 - 15 cm in length were placed into the aortic arch from right common carotid, left common carotid and left axillary arteries, until the tip of each graft reached into the ascending aorta. Through one femoral artery, the aortic stent-graft was positioned and delivered. Soon after, the parallel grafts were sequentially delivered. Self-spanding Wallstents(R) were used for parallel grafts reinforcement. Ballooning was routinely used for parallel grafts and rarely for aortic graft.Results: This technique was used in 2 cases. The first one was a lady with 72 years old, with an aortic retrograde dissection from left subclavian artery and involving remaining arch branches. Through right common carotid artery a stent-graft was placed in the ascending aorta and through the left common carotid artery a ViaBahn was inserted parallel to the former. A thoracic endograft then covered all the aortic arch dissection extending into the ascending aorta close to the sinu-tubular junction. The second case was a 82 year old male patient with a 7 cm aortic arch aneurysm. Through both common carotid arteries ViaBahn grafts were introduced and positioned into the ascending aorta. Soon after, the deployment of the thoracic stent graft covered all parallel grafts of the aortic arch, excluding the aneurysm. Both cases did not have neurologic or cardiac complications and were discharged 10 days after the procedure.Conclusions: This technique may be a good minimal invasive off-the-shelf technical option for aortic arch "debranching". More data and further improvements are required before this promising technique can be widely advocated. (C) 2011 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Avaliação quantitativa das dimensões óculo-palpebrais em portadores de cavidade anoftálmica em uso de prótese ocular externa

OBJETIVOS: Avaliar o posicionamento palpebral em portadores de cavidade anoftálmica com e sem prótese ocular externa, utilizando o processamento de imagem digital. MÉTODOS: Dezoito pacientes foram avaliados qualitativa e quantitativamente na Faculdade de Medicina de Botucatu - Universidade Estadual Paulista - UNESP, com e sem a prótese externa. Usando imagens obtidas por filmadora e processadas usando o programa Scion Image, mediu-se a altura do sulco palpebral superior, a altura da fenda palpebral e os ângulos palpebrais dos cantos interno e externo. RESULTADOS: Pseudo-estrabismo e sulco palpebral superior profundo foram as alterações mais freqüentes ao exame externo. Houve diferença significativa em todas as variáveis estudadas, com diminuição da altura do sulco palpebral superior, aumento da área da fenda palpebral e aumento dos ângulos palpebrais interno e externo quando o paciente estava usando a prótese externa. CONCLUSÃO: Todos os pacientes avaliados apresentaram algum tipo de anormalidade órbito-palpebral, o que reflete a dificuldade em se proporcionar ao portador de cavidade anoftálmica um aspecto idêntico ao que existe na órbita normal. O processamento de imagens digitais permitiu avaliação objetiva das dimensões óculo-palpebrais, o que poderá contribuir nas avaliações seqüenciais dos portadores de cavidade anoftálmica.

Effect of Passive Fit Absence in the Prosthesis/Implant/Retaining Screw System: A Two-Dimensional Finite Element Analysis

The misfit between prostheses and implants is a clinical reality, but the level that can be accepted without causing mechanical or biologic problem is not well defined. This study investigates the effect of different levels of unilateral angular misfit prostheses in the prosthesis/implant/retaining screw system and in the surrounding bone using finite element analysis. Four models of a two-dimensional finite element were constructed: group I (control), prosthesis that fit the implant; groups 2 to 4, prostheses with unilateral angular misfit of 50, 100, and 200 mu m, respectively. A load of 133 N was applied with a 30-degree angulation and off-axis at 2 mm from the long axis of the implant at the opposite direction of misfit on the models. Taking into account the increase of the angular misfit, the stress maps showed a gradual increase of prosthesis stress and uniform stress in the implant and trabecular bone. Concerning the displacement, an inclination of the system due to loading and misfit was observed. The decrease of the unilateral contact between prosthesis and implant leads to the displacement of the entire system, and distribution and magnitude alterations of the stress also occurred.

Computer-Guided Surgery in Implantology: Review of Basic Concepts

The aim of the present study was to conduct a critical literature review about the technique of computer-guided surgery in implantology to highlight the indications, purposes, immediate loading of implants and complications, protocol of fabrication, and functioning of virtual planning software. This literature review was based on OLDMEDLINE and MEDLINE databases from 2002 to 2010 using the key words "computer-guided surgery" and "implant-supported prosthesis." Thirty-four studies regarding this topic were found. According to the literature review, it was concluded that the computer-assisted surgery is an excellent treatment alternative for patients with appropriate bone quantity for implant insertion in complete and partially edentulous arches. The Procera Nobel Guide software (Nobel Biocare) was the most common software used by the authors. In addition, the flapless surgery is advantageous for positioning of implants but with accurate indication. Although the computer-guided surgery may be helpful for virtual planning of cases with severe bone resorption, the conventional surgical technique is more appropriate. The surgical guide is important for insertion of the implants regardless of the surgical technique, and the success of immediate loading after computer-guided surgery depends on the accuracy of clinical and/or laboratorial steps.

O uso da prótese na correção das hérnias da parede abdominal é um avanço, mas o seu uso indiscriminado, um abuso

The objective is to alert the surgeon about the indiscriminate use of synthetic prosthesis in the correction of inguinal and incisional hernias. The authors provide a brief history of surgery on hernias and a review of the literature, showing the importance of classifying inguinal hernias to fit the type of surgical correction with the defect found, abstaining from treating all hernias, with the same type of surgical procedure. In our opinion, small indirect inguinal hernias (type 1 and 2 of Gilbert) and hernias in women must not, in general, be treated with prostheses. The synthetic material should be reserved for direct and large indirect hernias. Even so, this attitude, besides determining a higher cost for the procedure, can lead to important complications such as infection, rejection, fistula formation, chronic pain, alterations in spermatogenesis and the possibility of carcinogenesis, according to more recent reports. The physiology and anatomy of the abdominal wall should be considered when dealing with incisional hernia corrections, where the surgeon can choose among many techniques to correct those defects, and in selected cases, utilize synthetic material. We conclude that although the use of biomaterials has constituted a great advance in surgery for abdominal wall hernia corrections because they decrease recurrences, and permit treatment of large abdominal hernias, the indiscriminate prosthesis usage is an abuse, and it can determine many serious complications, certainly avoidable with a well indicated non mesh technique .