A cross-sectional study of the anatomy of the jaws of a central-European caucasian population using cone beam computer tomography as a prerequisite for designing pre-formed calcium phosphate cement scaffolds

PURPOSE

This study aims to measure the cortical and cancellous bone thickness in the upper and lower jaws, serving as a data template for developing pre-defined calcium phosphate cement primary implant forms. These measurements are crucial for creating a biphasic scaffold.

METHODS

Forty complete jaws were assessed for cortical bone shape and thickness using statistical analysis and specific software tools. Sex and age were considered, and four groups were created.

RESULTS

The cumulative thickness of the cortical layer varied from region to region. In both the upper and lower jaws, the cortical layer in the molar region was significantly thicker than in the frontal region. Within the alveolar process, cortical thickness increases with distance from the alveolar crest on both sides. The oral side of the lower jaw is significantly thicker than the vestibular side. For the upper jaw, no significant differences between the oral and vestibular sides were found in this study. Additionally, it is noteworthy that men have a significantly thicker cortical layer than women. Regarding age, no significant overall differences were found.

CONCLUSION

Mathematical analysis of anatomical forms using polynomial functions improves understanding of jaw anatomy. This approach facilitates the design of patient-specific scaffold structures, minimizing the need for costly and time-consuming planning and enabling more efficient implementation of optimal therapy.

Long-Term Mortality in Patients with Positive Lymph Nodes at the Time of Radical Prostatectomy

BACKGROUND

The aim of this study was to determine prognostic factors and to provide long-term mortality data in patients with positive lymph nodes at the time of radical prostatectomy in a sample with long-term follow-up.

METHODS

A total of 527 patients with complete data sets treated in the years 1992-2014 were studied. The median follow-up was 7.2 years. The median number of removed lymph nodes was 15. Age, year of surgery, Gleason score, local tumor stage, prostate-specific antigen level, lymph node density, lymph node count and the number of positive lymph nodes were included in multivariable competing risk analyses with prostate cancer mortality as endpoint.

RESULTS

After 20 years, 28% of patients (95% CI 20-36%) died from non-prostate cancer (competing) causes, whereas 29% (95% CI 23-36%) died from prostate cancer. Only lymph node density (stratified by the median of 11.1%; hazard ratio [HR] 1.66, 95% CI 1.04-2.64, p = 0.0340) and Gleason score (8-10 vs. <8: HR 5.97, 95% CI 3.18-11.23, p < 0.0001) were independent predictors of prostate cancer mortality. Patients with a Gleason score <8 and a lymph node density < median had a 20-year prostate cancer mortality of only 5% (95% CI 0-10%), whereas this rate in patients with Gleason score 8-10 and a lymph node density ≥ median was 44% (95% CI 32-56%), p < 0.0001.

CONCLUSIONS

Mortality in patients with positive lymph nodes was determined by tumor aggressiveness and the relative extent of spread; neither the year of surgery nor the number of removed lymph nodes was associated with outcome. Patients with a lymph node density of <11.1% and a Gleason score <8 had an excellent long-term outcome.