Bone density assessments of dental implant sites: 1. Quantitative computed tomography

PURPOSE: This study was designed to evaluate variations of bone density in designated implant sites using quantitative computed tomography (QCT) and to compare the QCT measurements to subjective evaluation of bone density. MATERIALS AND METHOD: Sixty-two designated implant sites in jaws of 9 human cadavers were used. Indicator rods, 2 mm in diameter, were placed in all sites. CT images representing 1-mm buccolingual slices immediately mesial and distal to the rods were selected. Bone density (in Hounsfield units) was assessed in a standardized implant area superimposed on the images and was also subjectively evaluated by 2 independent examiners using the Lekholm and Zarb classification. RESULTS: QCT results demonstrated that bone densities may vary markedly when different areas of a designated implant site are compared. The Lekholm and Zarb ratings for the 2 examiners showed coefficients of correlation ranging between 0.5 to 0.7 for the relationships with the QCT values. Within each of the scores used for the subjective classification, however, a wide range of QCT values was observed. DISCUSSION: The results emphasize the importance of the use of radiographic methods prior to implant placement that allow topographically precise assessments of bone density in the region of interest. CONCLUSION: Access to QCT values should constitute a valuable supplement to subjective bone density evaluations prior to implant placement.     

Evaluation of bone-implant integration: efficiency and precision of 3 methods.

Computer-assisted planimetry, computer-assisted lineal analysis, and point-counting stereology have been compared with respect to their reproducibility and the time required to analyze bone-implant integration. Sections of 6 threaded dental implants selected from a bone augmentation experiment for their wide range of new bone formation were analyzed by each method 3 times. The bone density and percentage of osseous integration were evaluated at 4 sites around each implant section. It was found that computer-assisted planimetry demonstrated a modest but significantly greater variance (P < .05) in bone density estimates when compared to the computer-assisted lineal analysis and point-counting methods. Computer-assisted planimetry requires a different method of measuring each parameter and separate fields of view to evaluate fields distant from the implant. However, this can all be accomplished with line probes, as in computer-assisted lineal analysis, which extend from the implant surface into the surrounding alveolar bone. Whereas computer-assisted planimetry requires a separate identification of the perimeter of each field to be analyzed (next to and distant from the implant), computer-assisted lineal analysis allows expansion of the field to be evaluated without creating a new field of view. Also, following a limited learning curve, both point-counting and computer-assisted lineal analysis required less time to complete than did computer-assisted planimetry.     

Subjective criteria and probing attachment loss to evaluate the effects of plaque control and root debridement

11 adult patients with moderate to advanced periodontitis were treated with oral hygiene instruction and an initial, single episode of root debridement. Before therapy, 3 independent clinicians examined all patients and identified sites that in their opinion probably would not respond to the therapy and would continue to lose attachment. On 2 occasions, 3 and 12 months later, the clinicians re-examined and re-evaluated all patients and all sites. The results of therapy were also monitored by probing attachment level measurements performed every 3rd month. All 11 patients completed 24 months of follow-up, and 6 subjects were available until 36 months. Sites with probing attachment loss after 12, 24 and 36 months were identified using linear regression analysis and compared to the clinicians' prediction of probing attachment loss. The results demonstrated a limited agreement between probing attachment loss determined by linear regression and the clinicians' predictions of probing attachment loss. It appears that the traditional clinical signs and factors used to forecast and identify periodontal disease activity are only moderately associated with probing attachment loss. This suggests that attachment loss may be caused by several factors, at least following initial therapy. The progression of an inflammatory disease of microbial etiology may be only 1 of such causes. Further studies are needed to clarify the nature and cause of probing attachment loss.     

Towards a viable and just global nursing ethics

Globalization, an outgrowth of technology, while informing us about people throughout the world, also raises our awareness of the extreme economic and social disparities that exist among nations. As part of a global discipline, nurses are vitally interested in reducing and eliminating disparities so that better health is achieved for all people. Recent literature in nursing encourages our discipline to engage more actively with social justice issues. Justice in health care is a major commitment of nursing; thus questions in the larger sphere of globalization, justice and ethics, are our discipline's questions also. Global justice, or fairness, is not an issue for some groups or institutions, but a deeper human rights issue that is a responsibility for everyone. What can we do to help reduce or eliminate the social and economic disparities that are so evident? What kind of ethical milieu is needed to address the threat that globalization imposes on justice and fairness? This article enriches the conceptualization of globalization by investigating recent work by Schweiker and Twiss. In addition, I discuss five qualities or characteristics that will facilitate the development of a viable and just global ethic. A global ethic guides all people in their response to human rights and poverty. Technology and business, two major forces in globalization that are generally considered beneficial, are critiqued as barriers to social justice and the common good.     

Case of Justified Therapeutic Placebo Use

Placebos are substances or interventions that have no known intrinsic value in treating the condition for which they are given (Beauchamp & Childress, 1994). In research, the placebo effect is a well-described nuisance variable that researchers attempt to control through research design. In therapeutic management, particularly in nursing, placebo use is almost universally condemned as a deceptive practice (Bandman & Bandman, 1995; Fox, 1994).     

The honesty effect

Anne Barnhill focuses her article in this issue on the American Medical Association's ethics policy governing clinical use of placebos, but the implications of her analysis are deeper, touching on how physicians should make judgments about which interventions to offer patients in the process of shared decision‐making. The bottom line is that, even if an undisclosed placebo might be marginally more effective for a particular patient in the short term, over the long haul the integrity of the patient‐physician relationship relies on doctors being honest with their patients. Even when it comes to placebos, honesty remains the best policy.