Improvement of an additively manufactured subperiosteal implant structure design by finite elements based topological optimization.

To design a new subperiosteal implant structure for patients suffering from severe Maxillary Atrophy that lowers manufacturing cost, shortens surgical time and reduces patient trauma with regard to current implant structures. A 2-phase finite-element-based topology optimization process was employed with implants made from biocompatible materials via additive manufacturing. Five bite loading cases related to standard chewing, critical chewing force, and worst conditions of fastening were considered along with each specific result to establish the areas that needed to be subjected to fatigue strength optimization. The 2-phase topological optimization tested in this study performed better than the reference implant geometry in terms of both the structural integrity of the implant under tensile-compressive and fatigue strength conditions and the material constraints related to implant manufacturing conditions. It returns a nearly 28% lower volumetric geometry and avoids the need to use two upper fastening screws that are required with complex surgical procedures. The combination of topological optimization methods with the flexibility afforded by additively manufactured biocompatible materials, provides promising results in terms of cost reduction, minimizing the surgical trauma and implant installation impact on edentulous patients.

Calvarial Bone Grafting for Three-Dimensional Reconstruction of Severe Maxillary Defects: A Case Series.

PURPOSE: To evaluate the efficacy, associated morbidity, and results of a three-dimensional reconstruction technique for repairing severe defects of the maxilla using a calvarial autogenous bone graft and a soft tissue double-layered surgical approach in preparation for placing dental implants. MATERIALS AND METHODS: Bone defects of the maxilla consecutively reconstructed with calvarial autologous graft in the authors' institution were retrospectively evaluated. Patients with combined maxilla alveolar ridge defects with a width less than 4 mm and a height less than 7 mm (to the level of the maxillary sinus or the nostril), with at least three teeth involved, were included in the study. Calvarial bone blocks were sagittally sectioned in fine layers and fixed three-dimensionally in a boxlike structure with particulate bone inside. The purpose was to obtain an adequate amount of vertical and horizontal alveolar bone to enable restoration with dental implants at least 3.4 mm in diameter and 11 mm in length. RESULTS: Eleven reconstructive procedures were performed in 10 patients. Bone graft integration was successful in all of them. No major complications were observed in the donor cranial site. A mean bone gain of 5.04 mm (range, 3.4 to 7.8 mm) in height was obtained (standard deviation [SD], 1.69). The implant surgery was performed between the 15th and 19th weeks. A total of 28 implants were placed, and the mean follow-up time was 45 months (range, 23 to 65 months; SD, 12). The mean graft vertical resorption was 0.78 mm (range, 0.50-1.50 mm; SD, 0.00) 41 months after implant fixation. CONCLUSION: Three-dimensional reconstruction technique using calvarial bone grafts to restore severe segmental or crestal bone defects in the maxilla is an effective and predictable procedure that can increase the horizontal and vertical bone volume in preparation for the successful placement of dental implants.

Respuesta: Osteonecrosis maxilar asociada a bisfosfonatos / Reply: Bisphosphonate related osteonecrosis of the jaw

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Osteonecrosis maxilar asociada a bisfosfonatos e infección por Actinomyces / Bisphosphonate related osteonecrosis of the jaw and infection with Actinomyces

Fundamento y objetivo: La osteonecrosis maxilar asociada a bisfosfonatos (OMAB) ha centrado mucho interés desde su reciente descripción. Su patogenia aún no está aclarada; hasta hace poco tiempo se la consideraba una complicación no infecciosa, pero estudios recientes parecen implicar a bacterias del género Actinomyces. El objetivo del trabajo es analizar los casos de OMAB de nuestra institución. Pacientes y método: Revisión de historias clínicas de los pacientes con diagnóstico de OMAB en la consulta de Cirugía Maxilofacial de nuestro hospital. Resultados: Hemos encontrado 11 casos de OMAB: 4 mujeres en tratamiento con alendronato o risedronato oral por osteoporosis y 7 pacientes oncológicos en tratamiento con ácido zoledrónico intravenoso. En todos ellos se demostró invasión ósea por bacterias del género Actinomyces. En 9 casos se realizó tratamiento prolongado con amoxicilina con evolución clínica favorable en todos ellos, si bien 3 han fallecido por su neoplasia. Por el contrario, una paciente con alergia a betalactámicos y tratamiento irregular con eritromicina y tetraciclinas mantiene una evolución crónica de las lesiones. En otro paciente no hay información. Conclusiones: Actinomyces desempeña un papel importante en el desarrollo de OMAB y el tratamiento antibiótico específico mejora el pronóstico de este proceso(AU)

Background and objective: Bisphosphonate related osteonecrosis of the jaw (BRONJ) has raised considerable interest since its recent description. Its pathogenesis is not yet clarified; formerly it has been considered a non-infectious complication, but recent studies seem to implicate bacteria of the genus Actinomyces. The objective of this study is to analyze the cases of BRONJ in our institution. Patients and methods: Review of medical records of patients diagnosed of BRONJ in the Maxillofacial Surgery Unit of our hospital. Results: We have found 11 cases of BRONJ in our hospital: 4 women taking oral alendronate or risendronate for osteoporosis and 7 cancer patients treated with intravenous zolendronic acid. All of them showed bone invasion by bacteria of the genus Actinomyces. Nine patients underwent prolonged treatment with amoxicillin with favourable clinical outcome in all of them, but 3 died of their malignancy. By contrast, one patient with beta-lactamic allergy and irregular treatment with erythromycin and tetracycline had a chronic evolution of the lesions. There was no information for other patient. Conclusions: Actinomyces play an important role in the development of BRONJ and specific antibiotic treatment improves the prognosis of this process(AU)

[Bisphosphonate related osteonecrosis of the jaw and infection with Actinomyces]. / Osteonecrosis maxilar asociada a bisfosfonatos e infección por Actinomyces.

BACKGROUND AND OBJECTIVE: Bisphosphonate related osteonecrosis of the jaw (BRONJ) has raised considerable interest since its recent description. Its pathogenesis is not yet clarified; formerly it has been considered a non-infectious complication, but recent studies seem to implicate bacteria of the genus Actinomyces. The objective of this study is to analyze the cases of BRONJ in our institution. PATIENTS AND METHODS: Review of medical records of patients diagnosed of BRONJ in the Maxillofacial Surgery Unit of our hospital. RESULTS: We have found 11 cases of BRONJ in our hospital: 4 women taking oral alendronate or risendronate for osteoporosis and 7 cancer patients treated with intravenous zolendronic acid. All of them showed bone invasion by bacteria of the genus Actinomyces. Nine patients underwent prolonged treatment with amoxicillin with favourable clinical outcome in all of them, but 3 died of their malignancy. By contrast, one patient with beta-lactamic allergy and irregular treatment with erythromycin and tetracycline had a chronic evolution of the lesions. There was no information for other patient. CONCLUSIONS: Actinomyces play an important role in the development of BRONJ and specific antibiotic treatment improves the prognosis of this process.

Utility of bispectral index monitoring during intravenous sedation in the dental office.

PURPOSE: This research sought to compare two different systems to monitor sedated patients undergoing implant surgery in the dental office: the bispectral index (BIS) and the Ramsay scale. This information was used to establish an optimal BIS range for surgery in these patients and to calculate differences in drug consumption in both groups. MATERIALS AND METHODS: Consecutive patients undergoing implant surgery were studied and randomly assigned to two groups. Patients were sedated using intravenous propofol, fentanyl, and midazolam. The sedation level in group A was measured using the Ramsay scale. In group B, the Ramsay scale and the BIS were used together. Heart rate, blood pressure, and peripheral oxygen saturation were monitored in all patients. The levels of anxiety, satisfaction, and drug consumption were compared between groups. RESULTS: Forty-three patients were included; 20 were placed in group A and 23 were included in group B. There were no differences in the hemodynamic and respiratory parameters monitored or in anxiety or satisfaction levels in both groups. In group B patients, the BIS values stabilized around 85; the Ramsay scale stabilized around 3 in both groups and remained at these levels until the end of the procedure. Drug consumption was significantly lower in the BIS group. CONCLUSION: The optimal BIS value during intravenous sedation in sedated ambulatory patients in dental surgery should be within the 80 to 85 range. BIS monitoring allows for reduced consumption of propofol, fentanyl, and midazolam.