Implants in the severely resorbed mandibles: whether or not to augment? What is the clinician’s preference?

Contains fulltext : 96000.pdf (publisher's version ) (Open Access)INTRODUCTION: The aim of this study is to inventory in the Netherlands which therapy is the clinician's first choice when restoring the edentulous mandible. MATERIAL AND METHODS: A questionnaire was sent to all Dutch Oral and Maxillofacial surgeons. As part of this, the surgeons were invited to treat five virtual edentulous patients, differing only in mandibular residual height. RESULTS: In cases of a sufficient residual height of 15 mm, all surgeons were in favour to insert solely two implants to anchor an overdenture. In case of a residual height of 12 mm, 10% of the surgeons choose for an augmentation procedure. If a patient was presented with a mandibular height of 10 mm, already 40% of the OMF surgeons executed an augmentation procedure. Most (80%) surgeons prefer the (anterior) iliac crest as donor site. The choice of 'whether or not to augment' was not influenced by the surgeon's age; however, the hospital, where he was trained, did. Surgeons trained in Groningen were more in favour of installing short implants in mandibles with reduced vertical height. DISCUSSION: As the option overdenture supported on two interforaminal implants is reimbursed by the Dutch health assurance, this treatment modality is very popular in the Netherlands. From a point of costs and to minimize bypass comorbidity, surgeons should be more reluctant in executing augmentation procedures to restore the resorbed edentulous mandible as it is dated in literature that also in mandibles with a residual height of 10 mm or less, solely placing implants, thus without an augmentation procedure in advance, is a reliable treatment option

Reconstructive aspects in anterior skull base surgery

The treatment of malignancies of the anterior skull base is a coordinated multi-specialty approach that combines neurosurgery, otorhinolaryngology and oral and maxillofacial surgery. The reconstruction of the defects caused by tumor resection focuses on the separation of the intracranial contents from the facial bones and the re-establishment of an unobtrusive facial appearance. For an effective reconstruction regional and microvascular soft tissue flaps, grafting with autogenous bone and resorbable osteosynthesis plates play a major role. Anterior skull base tumors are managed using intracranial, extracranial or combined approaches. For the reconstruction of bony defects of the skull base, calvarial split bone grafts are used frequently. The fixation of the grafts can be carried out with resorbable plates in order to avoid the necessity of removal to a later point of time. For larger defects that may combine skull base defects and defects of bone and soft tissue of the face, the reconstructive options include myocutaneous and osteomyocutaneous microvascular flaps harvested from forearm, upper arm, fibula or the scapula. The different reconstruction techniques help to safely avoid cerebral spinal fluid leakage. The variety of techniques used for structural reconstruction of skull base and adjacent defects can be applied with a minimal complication rate in the patients. Intracranial abscess or osteomyelitis have not been encountered. Loss of bone grafts or complete necrosis of soft tissue flaps have not been observed. Although sophisticated reconstruction techniques are applied after the resection of anterior skull base malignancies, postoperative complications only occur in a minimal number of patients. Even the frequent application of postoperative irradiation did not seem to affect the graft survival. The different reconstruction techniques can be considered to be well established. The use of resorbable plates helps to reduce the number of secondary surgery for plate removal

Methylenetetrahydrofolate reductase polymorphism and minor increase of risk for oral cancer

Purpose: We investigated whether the mutant methylenetetrahydrofolate reductase (MTHFR) increases risk for oral cancer. The common germ-line mutation C677T in the MTHFR gene significantly diminishes specific activity of the enzyme, which is responsible for the circulating form of folate. Folate deficiency is associated with increased risk for thrombosis, as well as for several types of cancer, through disruption of DNA methylation, DNA synthesis and deficient DNA repair. Methods: We searched for the C677T mutation by restriction fragment analysis of PCR products in DNA samples of 110 patients with oral squamous cell carcinoma and 120 healthy controls of comparable ethnicity, age and sex. Results: The number of heterozygotes was significantly different in the two groups (P < 0.005), as well as in subgroups of patients with or without a positive family history for cancer, compared to normal controls (P < 0.01 and P < 0.005, respectively). Furthermore, the subgroup of patients with a positive family history for thrombophilia had a significant increase both in the frequencies of mutant alleles (P < 0.01) and heterozygotes (P < 0.001) in comparison to normal controls. Conclusions: The obtained results suggest that the MTHFR mutation is a minor contributing factor in oncogenesis in the oral region, in conjunction with low dietary uptake of folate

A clinical evaluation of the Zygoma fixture: One year of follow-up at 16 clinics

Purpose. To evaluate treatment outcome with Zygoma fixtures (Nobel Biocare, Goteborg, Sweden) with regard to fixture survival, patient satisfaction, and function of prosthesis replacement. Materials and Methods: The treatment outcome of 76 patients treated with 145 Zygoma fixtures at 16 centers was evaluated. Patient's and dentist's evaluations of the functional and aesthetic outcome of the treatment were assessed at delivery of prosthesis and at the 1-year follow-up visit. At the 1-year follow-up visit, the status of the peri-implant mucosa around the abutments and the amount of plaque were registered. Results: Sixty-six of the 76 patients, with 124 Zygoma fixtures supporting the prosthetic restorations, were evaluated at the 1-year follow-up. The overall survival rate for the Zygoma fixtures was 97.9% after 1-year of follow-up. Eighty percent of the patients were fully satisfied with both aesthetic and functional outcome at the time of prosthetic insertion and at the 1-year follow-up. All reported data from the dentists, with the exception of one restoration with several abutment screw loosenings, scored from acceptable to excellent for the aesthetic and functional outcome of the treatment. The status of peri-implant mucosa was recorded as normal in approximately 60% of the sites. Plaque, when present, was more often detected on the palatal surfaces compared with the buccal surfaces. Conclusion: This 1-year follow-up of Zygoma fixtures has shown good results with an acceptable number of minor complications and a majority of satisfied patients. (C) 2004 American Association of Oral and Maxillofacial Surgeons