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.

A single-centre retrospective 10-year experience of the rhombic 3D condylar fracture plate for open reduction and internal fixation of condylar neck and base fractures

Fractures of the mandibular condyle account for a significant proportion of mandibular fractures. The specific functional loads require particular specifications for the implant design used for open reduction and internal fixation of such fractures. The clinical and radiographic outcomes in patients treated using a single rhombic 3D condylar fracture plate for open reduction and internal fixation at a single institution, and who fulfilled the inclusion and exclusion criteria, are presented. The primary outcome variables were: occlusion, maximum interincisal distance and mandibular excursion at 1, 3, and 6 months postoperatively, and radiographic measurements for mandibular height and gonion angle. In total, 263 patients were included, of whom 173 (65.8%) were male and 90 (34.2%) female. The mean age was 40.4 ± 18.9 years. There was satisfactory occlusion in 98.9% of patients at the 6-month follow-up, and a significant improvement in all parameters for mandibular excursion (p < 0.001), with a reduced ramus height and an increase in the gonion angle on the fractured side. Excellent clinical and radiographic results were achieved using the rhombic-shaped implant, deeming it appropriate for the osteosynthesis of mandibular condyle fractures.

Development of a test bench for biomechanical simulation-a preliminary study of mandibular forces

Purpose: The aim of this study is to develop a test bench, which integrates different complexity levels and enables in that way a flexible and dynamic testing for mid and long term intervals as well as testing of maximum loads till implant failure of different osteosynthesis systems on the mandible. Material and Methods: For this purpose, an analysis of the state of the art regarding existing test benches was combined with interviews of clinical experts to acquire a list of requirements. Based on these requirements a design for a modular test bench was developed. During the implementation of the test stand, functional tests were continuously carried out and improvements made. Depending on the level of complexity, the test bench can be used either as an incorporated variant or as a standalone solution. In order to verify the performance and the degree of fulfilment of the requirements of these two variants of the test bench, preliminary studies were carried out for all levels of complexity. In these preliminary studies, commercially available osteosynthesis and reconstruction plates were investigated for their biomechanical behaviour and compared with data from the literature. Results: In total, fourteen test runs were performed for the different levels of complexity. Firstly, five test runs were executed to test the simplified load scenario in the incorporated variant of the test bench. High forces could be transmitted without failure of the miniplates. Secondly a quasi-static test scenario was examined using the incorporated variant with simplified load insertion. Five experiments with a number of cycles between 40,896 and 100,000 cycles were carried out. In one case the quasi-static testing resulted in a fracture of the tested reconstruction plate with a failure mode similar to the clinical observations of failure. The last four test runs were carried out using the standalone variant of the test bench simulating complex load patterns via the insertion of forces through imitated muscles. During the test runs joint forces were measured and the amplitude and vector of the resulting joint forces were calculated for both temporomandibular joints. Differences in the force transmission depending on the implant system in comparison to the zero sample could be observed. Conclusion: The presented modular test bench showed to be applicable for examination of the biomechanical behavior of the mandible. It is characterized by the adjustability of the complexity regarding the load patterns and enables the subsequent integration of further sensor technologies. Follow-up studies are necessary to further qualify and optimize the test bench.

Socioeconomic disparities between oral cavity cancer patients in Germany

Objective

In many countries the access to high quality medical service depends on socioeconomic factors. Therefore, these factors are associated with the treatment and prognosis of many diseases. In Germany health care is claimed to be independent from such factors due to obligatory health insurance and a well-developed medical infrastructure. Thus, socioeconomically caused health disparities should be absent. The aim of this study was to analyze the association between socioeconomic factors and the survival of oral cavity cancer in Germany.

Patients and methods

In this descriptive cohort study socioeconomic status related factors as well as demographic, tumor-specific, and comorbidity factors of 500 patients treated for oral cavity cancer were obtained in the university hospital of Dresden. Pearson correlation was used to describe associations between continuous variables. Associations between categorical variables were assessed using the chi-square test. Overall and recurrence-free survival were studied using the Kaplan-Meier method. Log-rank test was carried out to test between-group differences. Cox proportional hazard models were used to estimate the risk of death and the risk of recurrence.

Results

Significant differences in overall survival were found between the different educational levels and sex. Seventy-nine percent of the patients did not have a university degree or master craftsman/craftswoman. Less discrepancy was observed according to the marital status (49.4% married/engaged vs. 47.8% single, divorced, or widowed). In the multivariable analysis only sex, age at diagnosis, the Charlson score, the number of positive lymph nodes, and the nodal status were identified as independent predictors for overall survival whereas sex and the age at diagnosis were identified as independent predictors for recurrence-free survival.

Conclusion

Despite the equitable health system in Germany, significant associations between overall survival of oral cavity cancer and different socioeconomic factors could be found. For elimination of these disparities, health education programs should be established in socially deprived areas. Furthermore, clinicians should keep these factors in mind when determining recall periods for dental check-ups.

Long-term Outcomes After Pulmonary Endarterectomy in 499 Patients Over a 20-Year Period

BACKGROUND

Pulmonary endarterectomy (PEA) is a curative treatment for chronic thromboembolic pulmonary hypertension (CTEPH). Pulmonary hypertension (PH) after PEA is not uncommon, and its impact on long-term outcomes is poorly understood. We investigated the effects of residual PH on current long-term survival and on postoperative status.

METHODS

Data of 499 consecutive patients who underwent PEA between December 1995 and December 2014 were analyzed retrospectively. Kaplan-Meier survival analysis was used to estimate the survival rates with the 95% confidence interval.

RESULTS

Overall survival at 5, 10, and 15 years postoperatively was 84.8% ± 1.9%, 77.1% ± 2.7%, and 59.2% ± 5.3%, respectively. Survival after discharge at 5, 10, and 15 years was 93.9% ± 1.5%, 85.4% ± 2.6%, and 65.6% ± 5.8%, respectively. Of all, 166 patients had residual PH immediately after PEA and a poorer prognosis regarding freedom from CTEPH-related death. CTEPH-related survival at 10 years in patients with normal pulmonary artery pressure vs residual PH was 89.0% ± 2.7% vs 67.9% ± 4.7%, respectively (P < .001). There was a trend to CTEPH-related survival after discharge being affected by residual PH (P = .092). At follow-up, patients with residual PH had worse exercise tolerance (P < .001) and symptoms (P < .001) compared with those with normal pulmonary artery pressure. The probability of developing PH over time was 41.9% at 15 years.

CONCLUSIONS

Survival after hospital discharge is excellent for patients undergoing PEA. Postoperative PH is associated with more symptoms and poorer functional capacity. Patients who have clinically relevant postoperative PH should be monitored closely and may be candidates for additional medical therapy.

Development of a taxonomy of therapist difficulties: initial report

While psychotherapists discuss amongst themselves and in supervision the struggles they experience face-to-face with their patients, empirical study of therapists' experience of psychotherapy has been scant and there has been little investigation of therapists' difficulties. We require tools for such investigation and in this initial report we describe the development of a taxonomy of situations that psychotherapists experience as difficult and indicate lines of research to which the taxonomy might be applied. We also suggest that our procedure might serve as a model of collective self-study for other groups of practitioner-researchers. Using accounts of our own difficulties as therapists, we constructed a consensual set of experimental categories that could be applied to describe them. These were designated as Therapist (T)-Incompetent, T-Damaging, T-Puzzled, T-Threatened, T-Out of Rapport, T's Personal Issues, Painful Reality/T's Ethical Dilemma (a combined category), T-Stuck, and T-Thwarted. We then employed a fresh set of 30 accounts, which were also drawn from our own experience but had not contributed to the development of the taxonomy, to study the taxonomy's reliability. Each of us rated the presence and predominance of the categories for each of the 30 accounts. Both presence and predominance of all nine categories in the taxonomy could be reliably identified, with about three raters required to ensure good reliability for all categories; alphas (for our group of seven raters) were in the range 0.88-0.95 for presence-absence and 0.83-0.94 for predominance. We conclude that the taxonomy is a serviceable tool for further investigation. We also show that we are discriminable from one another as therapists in terms of the kinds of difficulty we reported, differences amongst us conforming to what we know of one another's therapeutic practice. We note implications for the diagnostic use of the taxonomy in training and supervision.