Removal of fractured cylindrical implants

The implant fracture is a rare but significative complication which requires a specific treatment for the surgical removal of the fractured fixture and the modification of the initial prosthetic plan. On the basis of the most recent studies and of a case personally observed in which both the osteointegrated supporting implants of a maxillary overdenture were fracturated, epidemiological, etiopathogenic, diagnostic and therapeutical aspects of this complication are analyzed. Clinical situations most at risk are emphasized, including implant-supported maxillary overdenture, and the major etiologic factors, represented by defects in implant design or material and physiologic or biomechanical overload. The diagnostic criteria are described along with the three therapeutical possible options: 1) removal of the fractured implant, replacement of the implant and refabrication of the prosthesis; 2) modification of the existing prosthesis leaving the fractured portion of the implant in place; 3) modification of the fractured implant and refabrication of a portion of the prosthesis. Three surgical removal technics are then illustrated (block-section, vestibular approach, occlusal approach), with the emphasis on the one choosed in the case examined, in which the ostectomy around the remaining fixture has been carried out with a trephine drill in order to contain the bone loss.     

Usefulness of the Aesthetic Result as a Success Criterion for Implant Therapy: A Review

Purpose: The purpose of this study was to review the reported evaluation criteria of the aesthetic result in oral implant rehabilitation. Materials and Methods: A literature search of MEDLINE, the Cochrane Collaboration, and EMBASE was performed to retrieve studies published between January 1990 and December 2008 using the following key words: “dental implants,”“clinical trial,” and “aesthetic index” (and their synonyms). A manual search of the literature published in the same period was also carried out using the following publications: Clinical Oral Implant Research, The International Journal of Oral and Maxillofacial Implants, and The International Journal of Periodontics and Restorative Dentistry. The inclusion criteria of the published studies were the following: human clinical trial, oral implant rehabilitation, at least 10 implants, at least 6 months of follow‐up from insertion of the prosthesis, and evaluation of the aesthetic result by means of an index. Results: The literature search revealed 650 relevant bibliographic references, of which 89 were selected for further analysis. A final total of 29 articles fulfilled the inclusion criteria; these included 10 retrospective case series, 11 prospective case series, 1 retrospective controlled clinical trial, 1 prospective controlled clinical trial, and 6 randomized controlled clinical trials. In general, evaluations of aesthetic results appear only in the more recent studies and refer mostly to implant rehabilitation in the maxillary anterior zone; the index used, in most cases, was the Papilla Index of Jemt. Conclusions: Although there appears to be a growing interest in aesthetics in dental implantology, there are as yet no universally accepted evaluation criteria of the aesthetic result. Therefore, further research is necessary to establish a common, complete, and reproducible index for the evaluation of aesthetic outcome that can add in the success criteria for implant therapy in the maxillary and mandibular anterior areas.     

Liver involvement in essential mixed cryoglobulinemia

Summary Twenty-one of 30 patients with essential mixed cryoglobulinemia (EMC) had evidence of liver involvement. The liver disease was characterized by the absence of clinical symptoms, hepatosplenomegaly, mild elevation of enzymes, abnormal BSP retention and low albumin levels. Histology, available in 12 patients, showed either chronic persistent or chronic active hepatitis or liver cirrhosis; 44% of the patients had HBsAg or HBsAb in sera and/or cryoglobulins, confirming the high frequency of exposure to hepatitis B virus (HBV) infection in EMC. However, liver lesions were similar in all patients, regardless of HBV exposure. Since other factors usually associated with chronic liver diseases were absent or apparently irrelevant, it is temptative to speculate that a ‘cryoglobulinemic hepatitis’ may exist as a distinct syndrome. The characteristic complement profile of the patients with EMC (low CH₅₀ and C4, normal C3PA), not related to albumin levels, can help to differentiate this disease from chronic liver disease without cryoglobulins. A preliminary report of this work was presented at the XIV International Congress of Rheumatology, San Francisco, Calif., USA, on June 27, 1977.     

Selection of a T-cell line resistant to stavudine and zidovudine by prolonged treatment with stavudine

It has been demonstrated that prolonged treatment with nucleoside analogues, such as 3'-azido-3'-deoxythymidine (zidovudine), 2',3'-dideoxycytidine (zalcitabine) and 9-(2-phosphonylmethoxyethyl) adenine (PMEA), may cause selection of cells that are resistant to their anti-HIV activity. A human T-lymphoblastoid cell line that is resistant to the antiviral and cytotoxic activity of 2',3'-didehydro-3'-deoxythymidine (stavudine) has developed as a result of prolonged treatment. These cells, called CEMstavudine, are also less sensitive to zidovudine. The cellular/pharmacological resistance acquired by the CEMstavudine cells is relatively low and appears to correlate with a reduction in thymidine kinase (TK) activity, rather than with a decreased expression of TK mRNA.