Daniele De Santis

Surface Roughness of Commercial Composites after Different Polishing Protocols: An Analysis with Atomic Force Microscopy

Background and Aims: Polishing may increase the surface roughness of composites, with a possible effect on bacterial growth and material properties. This preliminary in vitro study evaluates the effect of three different polishing systems (PoGo polishers, Enhance, Venus Supra) on six direct resin composites (Gradia Direct, Venus, Venus Diamond, Enamel Plus HFO, Tetric Evoceram, Filtek Supreme XT). Materials and Methods: For each composite, 12 square specimens were prepared: 9 specimens were polished, three for each different method, while three specimens were used as controls. Surface roughness was determined with AFM by measuring Root Mean Square (RMS) of average height. Results: PoGo polisher determined a significantly rougher surface, versus controls, in 5 out of 6 composites evaluated. Some significant differences from unpolished controls were observed also for Enhance polishing. Polishing with Venus Supra did not result in any significant difference in surface roughness versus controls. No differences were observed between different polishing systems. Conclusions: These preliminary results suggest that Venus Supra polishing system could determine a smoother composite surface if compared to the other polishing systems tested. On this basis, we are conducting an in vivo study to evaluate bacterial colonization on some combinations of composites and polishing protocols.

Guided bone regeneration with autogenous block grafts applied to Le Fort I osteotomy for treatment of severely resorbed maxillae: a 4- to 6-year prospective study.

INTRODUCTION Edentulism causes progressive bone resorption of the maxillae, which can lead to altered maxillo-mandibular relationships. The aim of the study was to evaluate the applicability of guided bone regeneration (GBR) to Le Fort I osteotomies with interpositional bone grafts for treatment of patients with severe maxillary atrophy. MATERIALS AND METHODS Twenty consecutive patients characterized by severely atrophic maxillae were treated from January 2003 to January 2006 in order to resolve maxillary edentulism. All patients underwent pre-prosthetic surgery, including a Le Fort I osteotomy associated with autologous interpositional bone grafts to move the alveolar arch forward and to resolve the maxillary atrophy. Barrier membranes were also used to cover the bone grafts and the osteotomy line, favoring the healing process according to GBR principles. Maxilla advancement and alveolar crest augmentation were measured to assess the degree of reconstruction. A total of 154 implants were inserted in reconstructed maxillae 4 months after surgery and were restored with fixed full-arch dentures after another 4 months. Surgical and prosthetic complications were recorded and previously established implant success criteria were used to assess the success of this treatment protocol. RESULTS The outcome of pre-prosthetic surgery and implant-supported rehabilitation was prospectively evaluated every year. All Le Fort I osteotomies were successfully carried out, with a mean maxilla advancement of 4.2 cm (range: 3.1-5 cm), which appeared to be stable during the follow-up. After a mean follow-up of 66.4 ± 18.4 months, only four implants failed according to the success criteria, yielding a cumulative success rate of 95.8%. DISCUSSION AND CONCLUSIONS Le Fort I osteotomies with the use of barrier membranes to cover the interpositional bone grafts can be a predictable treatment for edentulous patients with severely resorbed maxillae. The study data suggest that this approach makes it possible to compensate for both sagittal and vertical discrepancies due to maxilla atrophy, with a minimum resorption of advanced maxillae and grafted bone. A GBR-based protocol seems to lead to high implant success rates, although further randomized controlled studies are needed to demonstrate the usefulness and advantageousness of GBR.

Application of the "All-on-Four" concept and guided surgery in a mandible treated with a free vascularized fibula flap.

Abstract In this article, we describe the first case in the literature in which 3D computer-assisted treatment planning and guided surgery enabled a patient affected by extreme paraphysiologic mandibular bone atrophy to be treated with a free vascularized fibula flap and, after a period of healing, the flapless installation of 4 immediately loaded dental implants. The computer-fabricated surgical guide allowed placement of the implants according to the “All-on-Four” concept in a proper spatial preplanned position and by tilting 1 implant, avoiding an area of bone discontinuity. Additionally, this technique allowed the production of a prefabricated temporary prosthesis, delivered after implant insertion, which could be immediately loaded. The use of a fibula flap makes it possible to create greater bone thickness while computer-assisted treatment planning and guided surgery provide several advantages over the traditional technique.

Computer-assisted surgery in the lower jaw: double surgical guide for immediately loaded implants in postextractive sites-technical notes and a case report.

Computer-assisted surgery is based on computerized tomography (CT) scan technology to plan the placement of dental implants and a computer-aided design/computer-aided manufacturing (CAD-CAM) technology to create a custom surgical template. It provides guidance for insertion implants after analysis of existing alveolar bone and planning of implant position, which can be immediately loaded, therefore achieving esthetic and functional results in a surgical stage. The absence of guidelines to treat dentulous areas is often due to a lack of computer-assisted surgery. The authors have attempted to use this surgical methodology to replace residual teeth with an immediate implantoprosthetic restoration. The aim of this case report is to show the possibility of treating a dentulous patient by applying a computer-assisted surgical protocol associated with the use of a double surgical template: one before extraction and a second one after extraction of selected teeth.

Zygomatic and Maxillary Implants Inserted by Means of Computer-Assisted Surgery in a Patient With a Cleft Palate

This report describes the possibility of treating a patient affected by unilateral cleft palate and an extremely atrophied edentulous maxilla using zygomatic implants inserted in a conventional manner and maxillary implants inserted by means of a computer-assisted surgery. A cross-arch prosthesis supported by 4 maxillary and 2 zygomatic implants may be an ideal mode of prosthetic rehabilitation for these kinds of patients. The use of zygomatic implants is essential to optimize load distribution and to increase prosthesis stability, whereas the use of computer-assisted surgery facilitates surgical procedures and makes it possible to improve patient satisfaction.

Computer-assisted surgery: double surgical guides for immediate loading of implants in maxillary postextractive sites.

Implant-supported prostheses are a predictable treatment of totally edentulous patients. Progresses in implantology allowed realizing prostheses that are supported by immediately loading implants. Implants can be inserted in the healed site as fresh extraction sites, without differences about long-term results. Using computer-assisted surgery, it is possible to insert implants in a predetermined position and to create a prostheses, which can be immediately fixed on the implants. Patients have major comfort and an immediate aesthetic and functional result. The use of computer-assisted surgery in fresh extraction sites is a procedure that has not been evaluated because of technical difficulties: teeth extraction eliminates references for surgical guides. The absence of guidelines to treat dentulous areas is often likely caused by lack of computer-assisted surgery: we attempted to use this procedure to replace residual teeth with an immediate implant prosthetic rehabilitation. The aim of this clinical report was to show the possibility to apply computer-assisted surgery in dentulous patient using a double surgical template: one before extraction and the other after extraction of selected teeth.

Odontogenic Orofacial Infections

Abstract Acute dental abscess is a frequent and sometimes underestimated disease of the oral cavity. The acute dental abscess usually occurs secondary to caries, trauma, or failed endodontic treatment. After the intact pulp chamber is opened, colonization of the root canals takes place with a variable set of anaerobic bacteria, which colonize the walls of the necrotic root canals forming a specialized mixed anaerobic biofilm. Asymptomatic necrosis is common. However, abscess formation occurs when these bacteria and their toxic products breach into the periapical tissues through the apical foramen and induce acute inflammation and pus formation. The main signs and symptoms of the acute dental abscess (often referred to as a periapical abscess or infection) are pain, swelling, erythema, and suppuration usually localized to the affected tooth, even if the abscess can eventually spread causing a severe odontogenic infection which is characterized by local and systemic involvement culminating in sepsis syndrome. The vast majority of dental abscesses respond to antibiotic treatment, however, in some patients surgical management of the infection may be indicated. In the present work, a retrospective analysis of the patients with dental orofacial infections referred to the Unit of Dentistry and Maxillofacial Surgery of the University of Verona from 1991 to 2011 has been performed.

Gene Expression of Human Mesenchymal Stem Cells Cultured on Titanium Dental Implant Surfaces.

Objective: The study shows how the influence of titanium surfaces on human mesenchymal stem cells differentiates toward osteocytes lineage and how, after growth, on machined titanium disk or etched titanium disk, changes, in gene expression for RUNX1, CTNNB1, SP7, and DLX5. Methods: Genes were analyzed by means of quantitative real-time polimerase chain reaction. Osseo genic lineage differentiation was also tested by means of the catenin-&bgr;1 immunofluorescence, induced osteoblasts, which represented the internal control. Results: The RUNX1 and SP7 expressions in the induced osteoblasts prove to be different, compared with cells cultured on metallic supports. Moreover, the levels of expression of the runt-related transcription factor 1 and the osterix appeared more down-regulated in cells that grew on a machined titanium surface. In the present experimental model, mRNA expression of DLX5 and CTNNB1 in human mesenchymal stem cells, cultured on each of the titanium surfaces, showed no differences, compared with osteoblast-induced cells. The immunofluorescence scores, for protein expression of beta-catenin in human mesenchymal stem cell treated cells, illustrates significantly improved results with the etched surface. Conclusions: Present results suggested that different titanium surfaces might induce some differences in terms of gene expression. The only gene analyzed, which proved significant differences between the 2 titanium supports, was SP7; however, the other 3 genes indicating the existence of differences between the 2 titanium groups.

A New Radiologic Protocol and a New Occlusal Radiographic Index for Computer-Guided Implant Surgery.

AbstractA minimum interarch space of 40 mm along the planned direction of the implant is physically mandatory to allow computer-guided implant placement with the NobelGuide technique. The aim of this paper was to describe a novel radiologic protocol and a new occlusal radiographic index that give the clinician the possibility of identifying patients with limited interarch space. Three patients undergoing NobelGuide treatment of the edentulous upper jaw were selected as candidates for this study. In the first patient, the radiographic occlusal index was built using an addition silicone material to occupy the space between the 2 arches forced into the maximum opening position. In the other 2 patients different silicone materials were used and 2 interpositional wedges were placed in between 2 silicone bites to ensure maximum mouth opening. In the first patient, the bite made with addition silicone alone resulted in distinct noise on computer tomography since the patient was not forced to achieve his maximum opening position. In the second patient the mandibular addition silicone was still quite visible, while in the third patient the condensation silicone was invisible and the quality of the image was excellent with the possibility of measuring maximum opening position and virtually predicting interference with the opposite arch. The new radiological occlusal index made with condensation silicone (Sandwich Index) proved to be effective in reproducing the maxillary forced maximum opening position during the initial planning phase, preventing errors in the inclusion or exclusion of patients suitable for NobelGuide treatment.

Rehabilitation of a complex midfacial defect by means of a zygoma-implant-supported prosthesis and nasal epithesis: a novel technique

PurposeSeveral authors have described zygoma implants as a reliable surgical option to rehabilitate severe maxillary defects in case of extreme atrophy or oncological resections. The aim of this study is to report a new technical approach to the rehabilitation of a complex oronasal defect by means of a zygoma-implant-supported full-arch dental prosthesis combined with a nasal epithesis.Patients and methodsThe patient presented with a subtotal bilateral maxillectomy and total rhinectomy defect because of a squamous cell carcinoma of the nose. No reconstructive surgery was performed because of the high risk of recurrence; moreover, the patient refused any secondary procedure. After surgery, the patient presented a wide palatal defect associated to the absence of the nasal pyramid. Zygoma-retained prostheses are well documented, and they offer good anchorage in rehabilitating wide defects after oncological surgery and a good chance for patients to improve their quality of life. We hereby describe two prosthetic devices rehabilitating two iatrogenic defects by means of a single intraoral implant-supported bar extending throughout the oronasal communication, thus offering nasal epithesis anchorage.ResultsAt 1-year follow-up after functional prosthetic loading, no implant failure has been reported. Clinical and radiological follow-up showed no sign of nasal infection or peri-implantitis. The patient reported a sensitive improvement of his quality of life.ConclusionsSimultaneous oral and nasal rehabilitation of complex oronasal defects with zygoma-implant-supported dental prosthesis and nasal epithesis represents a reliable surgical technique. According to this clinical report, the above-mentioned technique seems to be a valuable treatment option as it is safe, reliable and easy to handle for both surgeon and patient.