Anatomic Customization of Root-Analog Dental Implants With Cone-Beam CT and CAD/CAM Fabrication: A Cadaver-Based Pilot Evaluation.

Existing root-analog dental implant systems have no standardized protocols regarding retentive design, surface manipulation, or prosthetic attachment design relative to the site's unique anatomy. Historically, existing systems made those design choices arbitrarily. For this report, strategies were developed that deliberately reference the adjacent anatomy, implant and restorable path of draw, and bone density for implant and retentive design. For proof of concept, dentate arches from human cadavers were scanned using cone-beam computed tomography and then digitally modeled. Teeth of interest were virtually extracted and manipulated via computer-aided design to generate root-analog implants from zirconium. We created a stepwise protocol for analyzing and developing the implant sites, implant design and retention, and prosthetic emergence and connection all from the pre-op cone-beam data. Root-analog implants were placed at the time of extraction and examined radiographically and mechanically concerning ideal fit and stability. This study provides proof of concept that retentive root-analog implants can be produced from cone-beam data while improving fit, retention, safety, esthetics, and restorability when compared to the existing protocols. These advancements may provide the critical steps necessary for clinical relevance and success of immediately placed root-analog implants. Additional studies are necessary to validate the model prior to clinical trial.

Effect of mechanical strain on solute diffusion in human TMJ discs: an electrical conductivity study.

This study investigated the effect of mechanical strain on solute diffusion in human TMJ discs (mean cadaver age 77.8) using the electrical conductivity method. The electrical conductivity, as well as small ion diffusivity, of male and female TMJ discs was determined under three compressive strains. In the male group, the average disc electrical conductivity (mean ± SD) at 0% strain was 5.14 ± 0.97 mS/cm, decreased to 4.50 ± 0.91 mS/cm (-12.3%) at 10% strain, and 3.93 ± 0.81 mS/cm (-23.5%) at 20% compressive strain. Correspondingly, the average disc relative ion diffusivity at 0% strain was 0.44 ± 0.08, decreased to 0.40 ± 0.08 (-8.9%) at 10% strain, and 0.36 ± 0.08 (-16.7%) at 20% compressive strain. In the female group, the average disc electrical conductivity at 0% strain was 5.84 ± 0.59 mS/cm, decreased to 5.01 ± 0.50 mS/cm (-14.2%) at 10% strain, and 4.33 ± 0.46 mS/cm (-25.8%) at 20% compressive strain. Correspondingly, the average disc relative ion diffusivity at 0% strain was 0.49 ± 0.05, decreased to 0.43 ± 0.04 (-11.3%) at 10% strain, and 0.39 ± 0.04 (-19.9%) at 20% compressive strain. The results indicated that mechanical strain significantly impeded solute diffusion through the disc. This mechanical strain effect was larger in the female than in the male human TMJ disc. This study may provide new insights into TMJ pathophysiology.

Lecture recording system in anatomy: possible benefit to auditory learners.

The literature reports that using Learning Recording Systems (LRS) is usually well received by students but that the pedagogical value of LRS in academic settings remains somewhat unclear. The primary aim of the current study is to document students' perceptions, actual pattern of usage, and impact of use of LRS on students' grade in a dental gross and neuroanatomy course. Other aims are to determine if students' learning preference correlated with final grades and to see if other factors like gender, age, overall academic score on the Dental Aptitude Test (DAT), lecture levels of difficulty, type of lecture, category of lecture, or teaching faculty could explain the impact, if any, of the use of LRS on the course final grade. No significant correlation was detected between the final grades and the variables studied except for a significant but modest correlation between final grades and the number of times the students accessed the lecture recordings (r=0.33 with P=0.01). Also, after adjusting for gender, age, learning style, and academic DAT, a significant interaction between auditory and average usage time was found for final grade (P=0.03). Students who classified themselves as auditory and who used the LRS on average for fewer than 10 minutes per access, scored an average final grade of 16.43 % higher than the nonauditory students using the LRS for the same amount of time per access. Based on these findings, implications for teaching are discussed and recommendations for use of LRS are proposed.

Evaluation of a lecture recording system in a medical curriculum.

Recently, the Medical University of South Carolina adopted a lecture recording system (LRS). A retrospective study of LRS was implemented to document the students' perceptions, pattern of usage, and impact on the students' grades in three basic sciences courses (Cell Biology/Histology, Physiology, and Neurosciences). The number of accesses and length of viewings of the recordings were recorded per week for each student and correlated with the grades in each of the three courses. Attendance records were not available. The results showed considerable variability in the use of the LRS by both faculty and students during the entire semester and across all three courses, including week to week variations. Data indicated that 30% of the students did not use the LRS at all with 41% of the students using it very little (less than 10 times for a total of 131 recordings). Specific patterns of usage were identified for each of the three courses throughout the semester, with an increase in access prior or during examination weeks. However, the statistical analysis showed that there was no correlation between the final grades and the usage of LRS. Finally, a survey of the students' perception showed that 74% agreed/strongly agreed that the recordings were useful with 6% disagreeing/strongly disagreeing and 11% undecided. This study showed that the use of LRS might be a viable alternative for students unable to attend lecture due to circumstances such as illness but that more research is needed to truly understand the best pedagogical use of LRS.