Comparison of Maxillary Implant-Supported Prostpesis in Irradiated and Non-Irradiated Patients

In order to investigate the influence of radiation therapy after the treatment of maxillary implant-supported prostheses, 27 patients received a total of 131 implants in maxilla after oral cancer treatment and/or reconstructive surgery. Among them, 25 received maxillary implant-supported prostheses. The cumulative survival rates of implants and prostheses were evaluated by the product-limit-estimates method according to Kaplan-Meier. The cumulative survival rate of implants and prostheses in irradiated patients was compared with that in non-irradiated patients by statistical Log-rank test. The results showed that 112 implants were observed after implant loading. The implants cumulative survival rate was approximately 65 % for overall patients. The cumulative prosthesis successful rate was approximately 88 % for all 25 patients. Log-rank test analysis revealed that there was a significant difference in cumulative implants survival rates between non-irradiated and irradiated maxillary bone (P<0. 01). It was concluded that the implants and prostheses in irradiated patients have significantly lower survival rates than in non-irradiated patients.

Porcelain fracture of metal-ceramic tooth-supported and implant-supported restorations: A review

Metal-ceramic restorations are widely used in dentistry with a high degree of general success. However, fracture of these restorations does occur and usually frustrates both the dentist and the patient. Objective: This literature review discusses the factors that may lead to the fracture of these restorations whether they are tooth-supported or implant-supported with the aim of making dentists and technicians aware of these factors to avoid them. Factors reviewed include: technical factors, dentist-related factors, inherent material properties, direction, magnitude and frequency of applied loads, environmental factors, screw-retained implant-supported restorations, and posterior cantilevered prostheses. Material and Methods: A netbased search in “Pubmed” was performed and combined with a manual search. The search was limited to articles written in English. Conclusions: the published literature revealed that the factors predisposing to fracture of metal-ceramic restorations may be related to the technician, dentist, patient, environment, design of the restoration, or to inherent structure of ceramics and others. However, if the dentist and technician understand these factors and respect the physical characteristics of the materials, most of those are avoidable.

Implant-Supported Full Fixed Prostheses with a Removable Oro-Nasal Obturator for the Edentulous Maxilla with Palatal Fistula due to Surgical Procedures for Oral Cancer

Open oro-nasal defects resulting after oral tumor resection need structural and functional rehabilitation using dental prostheses. Conventional removable prostheses have usually been indicated and performed for prosthodontics. When the patient has an edentulous maxilla, the unfavorable stability of the prosthesis will cause dysfunction of mastication and pronunciation. To achieve improvement of the impaired functional situation, implant-supported full fixed prostheses (IPSPs) for the edentulous maxilla with a removable obturator offer a reasonable solution. We present herein the case of a 70-year-old Japanese man who has presented with oro-nasal defect due to surgical procedures for oral cancer. He was treated with implant-supported full fixed prostheses in a conventional two-step procedure. After prosthesis treatment, a palatal obturator was set. The patient has shown no clinical or radiological evidence of failure as of 24 months after the end of treatment. Functional evaluation of mastication and pronunciation showed dramatic improvements. For a patient with an edentulous maxilla and palatal fistula, full-arch fixed prostheses supported by a combination of axially and non-axially positioned implants and a removable oro-nasal obturator, using the anterior alveolar bone, without bone transplantation or maxillary sinus elevation, could offer an effective, minimally invasive treatment alternative.

Simultaneous Upper and Lower Jaw Extractions, Autogenous Bone Augmentation and Temporary Implant Placement with Immediate Loading

Aims: We expanded the known technique for simultaneously augmenting an atrophic maxilla and placement of immediate provisional implants (IPI), followed by immediate loading by performing surgery in both jaws simultaneously. Feasibility of this new technique, implant survival and success were evaluated as well as prosthetic success. Materials and Methods: All patients undergoing simultaneous bone grafting and IPI placement with immediate loading at our institute between the 1st of June 2016 and the 30th of May 2018 were included and followed up for at least one year postoperatively. Results: 3 patients were followed for a mean period of 25.67 months (20 - 29 months). 33 IPIs were placed. All were immobile at second stage surgery without signs of infection. No provisional bridges were lost and no infections were noted. After second stage surgery, none of these 36 final dental implants were lost. There was some bone loss at one implant. In all patients, good functional and aesthetic results were obtained without any unforeseen complications. This renders the implant survival at 100% and the success rate at 97%. Conclusion: The technique is complex due to the intricate step-by-step process that is required and depends on a dedicated team to ensure a proper workflow. When performed correctly, the protocol shows good and predictable results.