An in vitro comparison of the computerized tomography/CAD-CAM and direct bone impression techniques for subperiosteal implant model generation.

Subperiosteal implants are currently fabricated by using the classic two-stage direct bone impression technique or by the use of the one-stage computer tomography/computer-assisted design-computer-assisted manufacture (CT/CAD-CAM) method. This study compares the accuracy of the two techniques by using cadaver maxillae and mandibles as the models for fabrication of casts. Seven cadaver jaw specimens were collected and subjected to direct bone impressions and to CT scans. Those derived from the direct bone impressions were poured in die stone, while the CT scans were sent for fabrication of CAD-CAM-generated casts. On each of the 14 models so produced, a cast grid was fabricated that was designed as a measuring device. The preciseness of fit of each grid was subjected to analyses that presented levels of accuracy. Statistical evaluation of these levels, reduced to numerical indices, revealed that the direct bone techniques resulted in acceptable castings in seven of seven cases, whereas the CAD-CAM method yielded adequate castings in five of seven cases.

Evaluation of the Periotest as a diagnostic tool for dental implants.

The Periotest is examined as a possible replacement for outdated, inconsistent dental implant stability diagnosis tools. The Periotest has the advantage of offering reproducible findings by measuring the levels of subclinical mobility using an ultrasonically vibrating probe. The Periotest is successful in assessing the stability status of an implant, but it can detect the quantity of bony osseointegration only in terminal cases. Radiography proved to be a more sensitive method of determining pericervical bone loss; therefore, periapical radiographs in addition to the Periotest device were found to offer the most reliable assessment of an implant's status.

Application of a first-pass effect model to characterize the pharmacokinetic disposition of venlafaxine after oral administration to human subjects.

Venlafaxine (VEN), a drug used in the treatment of depression, undergoes significant first-pass metabolism after oral dosing to O-desmethylvenlafaxine (ODV), a metabolite with comparable therapeutic activity to that of parent drug. The pharmacokinetic disposition of VEN was characterized using a "first-pass" model that incorporates a presystemic compartment (liver) to account for the first-pass metabolism of VEN to ODV. A series of differential equations were simultaneously fitted to plasma concentrations of parent and metabolite. A good fit of the model to observed data was demonstrated, generating estimates for the following parameters: ka (1.31 +/- 0.009 hr-1), VVEN (252 +/- 87.6 liters), CLint (65.8 +/- 39.7 liters/hr), RL (liver:plasma partition coefficient, 29.6 +/- 18. 3), VODV (181 +/- 84.1 liters), and CLODV (23.5 +/- 12.5 liters/hr). Parameter estimates correlated closely with those obtained through noncompartmental methods. These results indicate that the time-course disposition of a compound undergoing first-pass hepatic metabolism after oral dosing can be successfully modeled.

Preceptorships in high-risk perinatal nursing for rural nurses: a pilot project.

A need existed in New Mexico to enhance the skills of nurses in rural areas in the management of high-risk perinatal patients. However, barriers prohibited initiating such a program, including: a) program development and approval; b) legal and insurance issues; c) determining financial responsibility; and d) application and selection process. Resolving these problems came in the form of a collaborative effort among three departments at the University of New Mexico. A preceptor program of clinical and classroom experiences was developed for nurses outside of the Albuquerque metropolitan area. Evaluations of the program at six months revealed that program participants had implemented changes in their nursing practice. Revisions of the program and plans for the future are discussed.