Innovative Solutions Using Zygoma Implants.

The severely resorbed edentulous maxilla presents significant treatment challenges. The introduction of remote implant support using zygoma implants has provided a plethora of treatment possibilities for many patients. This article presents four very different sets of circumstances successfully treated using this protocol.

The effect of casting procedures on rotational misfit in castable abutments.

PURPOSE: Misfit of implant components has been linked to restorative complications such as screw loosening. Although previous studies have shown a correlation between rotational misfit and screw loosening, the impact of casting procedures on rotational misfit is lacking. The aim of this in vitro study was to evaluate the effect of casting procedures on rotational misfit of cast abutments when compared to machined titanium abutments. MATERIALS AND METHODS: Forty-eight external hexagonal implants and 48 abutments were placed in 4 groups of 12 samples each: (1) machined titanium abutments, (2) premachined palladium abutments cast-on with palladium, (3) plastic burnout abutments cast with nickel chromium, and (4) plastic burnout abutments cast with cobalt chromium. Rotational misfit between the external hexagon of the implant and the internal hexagon of the abutment was measured using standardized techniques and recorded in degrees. Mean values for each group were analyzed with analysis of variance and Tukey test. RESULTS: The mean rotational misfit was 1.21 +/- 0.57 degrees for machined titanium abutments, 1.77 +/- 130 degrees for cast-on abutments, 1.98 +/- 0.72 degrees for cast NiCr abutments, and 2.79 +/- 1.13 degrees for cast CoCr abutments. Significantly greater rotational misfit was recorded with cast CoCr abutments when compared to machined titanium abutments (P < .05). CONCLUSION: Rotational misfit was less than 2 degrees for all groups except for cast CoCr abutments, which demonstrated a significantly greater rotational misfit.

A classification system to measure the implant-abutment microgap.

PURPOSE: A large microgap at the implant-abutment interface has been reported to result in adverse effects, including screw loosening, abutment rotation, and abutment fracture. However, a standardized classification of the implant-abutment interface has not been established. The purposes of this investigation were (1) to propose a classification system based on the horizontal and vertical microgap of the implant-abutment interface and (2) to compare the implant-abutment interface in 4 groups of abutments. MATERIALS AND METHODS: Forty-eight randomly selected external hexagonal implants were paired with (1) machined titanium abutments, (2) premachined palladium abutments cast-on with palladium alloy, (3) plastic burnout abutments cast with nickel chromium alloy, and (4) plastic burnout abutments cast with cobalt chromium alloy. A comparison of the horizontal and vertical microgaps at the implant-abutment interface was completed at 8 locations on each specimen to the nearest micrometer using an optical microscope with a magnification of 150x. Group means and significant differences between groups were determined by analysis of variance and Tukey multiple-comparisons post-hoc analysis. P < .05 was the threshold for statistical significance. RESULTS: There was no significant difference between groups with respect to vertical misfit. For horizontal misfit, machined titanium abutments presented significantly higher horizontal misfit compared to other groups (P < .001). Premachined cast-on abutments had significantly higher horizontal misfit than cast NiCr abutments (P < .001). In the proposed classification system, 23% of all sites measured at the implant-abutment interface had an ideal relationship, 34% had a horizontal discrepancy only, 4% had a vertical discrepancy only, and 39% had both vertical and horizontal discrepancies. CONCLUSION: The proposed implant-abutment classification system demonstrated a way to characterize and compare the microgap at the implant-abutment interface.

Treatment planning complications and surgical miscues.

It is critical to have an accurate understanding of the educational limitations of dentists because of a lack of formal training with implants. It is not a unilateral problem, as it can be easily discerned from the cases illustrated in this article. The team must pay attention to specific direction as to the number, location, depth, angulation, spacing, and distribution of implants in their patients. More and more experienced restorative dentists are incorporating implant treatment in their practice. There is more awareness and concern at having simple restorative cases turn into very complex undertakings that require extra chair time and additional laboratory expenses. To avoid treatment planning complications and surgical miscues the following is recommended: 1) always complete a detailed restorative and surgical examination; 2) do not place implants without a restorative prosthodontic workup; 3) refer the patient to an experienced dentist for the workup; 4) insist on a diagnostic wax-up; 5) insist on a radiographic and a surgical stent and use it during placement; 6) determine that the entire treatment team has the knowledge and experience to complete the case; 7) as a surgeon, be sure you understand the exigencies of fixed and removable restorative care; 8) make sure that team members have the same treatment vision; and 9) communicate. Never take anything for granted. Communicate.

Thirteen-year follow-up of a mandibular implant-supported fixed complete denture in a patient with Sjogren's syndrome: a clinical report.

This clinical report describes the treatment and long-term follow-up of a patient with Sjogren's syndrome treated with osseointegrated implants and a mandibular fixed complete denture. The implants and prosthesis have remained stable and functional for 13 years. Implant treatment may, therefore, offer a viable long-term treatment alternative for patients with Sjogren's syndrome.