Digitally Augmented Learning in Implant Dentistry.

The economic forces in the dental education industry yield a high cost for a dental degree, yet the financial return for this education yields a small margin above the costs for this degree. Industries with unfavorable return to investment ratios tend to be vulnerable to changes. Productive technologies are emerging that may be useful in improving the return to investment ratios in dental education. Virtual reality and online learning provide productive value that could be useful to the dental education industry. A description and use cases of virtual reality in dental implantology education are provided.

The effect of fracture comminution on the reliability and accuracy of radial head sizing.

BACKGROUND: Radial head implant sizing can be based on the maximum head diameter (D-MAX), the minimum head diameter (D-MIN), or the articular dish diameter (D-DISH). The purpose of this study was to assess the reliability of the different radial head sizing techniques and to investigate the effect of radial head fracture comminution on measurement accuracy. METHODS: Ten observers measured 11 cadaveric radial heads with 3 radial head features (D-MAX, D-MIN, and D-DISH diameter). Radial heads were then fractured into 2, 3, and 4 parts, and the measurements were repeated. Variability was assessed by intraclass correlation. The measurements were compared with the intact state to assess the effect of radial head fracture comminution on sizing accuracy. RESULTS: D-MAX and D-MIN measurements were the most reliable among all observers (intraclass correlation coefficients, 0.980, 0.973). The D-DISH measurement was less reliable (intraclass correlation coefficient, 0.643). Radial head comminution did not significantly affect the reliability of any measurement (P > .2). Fracture comminution, however, significantly affected measurement accuracy with D-MAX and D-DISH. With fracture comminution, D-MAX underestimated radial head diameter (-0.4 ± 0.3 mm; P < .001), whereas D-DISH overestimated diameter (+0.5 ± 0.4 mm; P < .001). Comminution did not significantly affect D-MIN (-0.1 ± 0.3 mm; P = .13). DISCUSSION: The D-MAX and D-MIN measurements were more reliable than D-DISH for diameter sizing of intact and comminuted radial heads. Overall, increasing comminution did not significantly affect measurement reliability. However, the accuracy of the D-MIN technique was least affected by comminution, suggesting that D-MIN should be used in selecting the diameter of a radial head implant.

An intra-bone axial load transducer: development and validation in an in-vitro radius model.

BACKGROUND: Accurate measurement of forces through the proximal radius can assess the effects of some surgical procedures on radioulnar load sharing, but is difficult to achieve given the redundant loading nature of the musculoskeletal system. Previously reported devices have relied on indirect measurements that may alter articular joint location and function. An axial load transducer interposed in the diaphysis of the radius may accurately quantify unknown axial loads of the proximal radius, and maintain articular location. METHODS: An in-vitro radius model was developed by interposing an axial load transducer in the diaphysis of the proximal radius. Static loads of 20, 40, 60, 80, and 100 N were applied with a servo-hydraulic actuator to the native radial head at angles of 10°, 20°, 30°, and 40° in the anterior, posterior, medial and lateral directions. FINDINGS: Linear regression of five repeatability trials showed excellent agreement between the transducer and applied loads (R (2) = 1 for all trials). For off-axis net joint loads, the majority of measured loading errors were within the inter-quartile range for mean loads up to 80 N. Loads below 80 N and outside the inter-quartile range had errors of less than 1 N. CONCLUSIONS: The repeatability and off-axis net joint load results of this study validate the effectiveness of the interposed axial load transducer to accurately quantify proximal radius loads. The surgical technique preserves the native articular location and soft-tissue constructs, like the annular ligament. The modular design allows for testing the effects of length-changing osteotomies in subsequent biomechanical studies.

Indomethacin reduces cell damage: shedding new light on compartment syndrome.

INTRODUCTION: Indomethacin may preserve tissue viability in compartment syndrome. The mechanism of improved tissue viability is unclear, but the anti-inflammatory effects may alter the relative contribution of tissue necrosis versus apoptosis to cellular injury. Existing studies have only considered indomethacin administration before induction of elevated intracompartment pressure. The purpose of this study was to determine the effect of timing of indomethacin administration on muscle damage in elevated intracompartment pressure and to assess apoptosis as a cause of tissue demise. METHODS: Twenty-four Wistar rats were randomized to elevated intracompartmental pressure (EICP) for either 45 or 90 minutes (30 mmHg). In the 45-minute cohort, indomethacin was withheld in Group 1 (CS45), given before induction of EICP in Group 2 (CS45Indo0), or given after 30 minutes of EICP/15 minutes before fasciotomy in Group 3 (CS45Indo30). In the 90-minute cohort, indomethacin was withheld in Group 4 (CS90) or given after 30 or 60 minutes of EICP in Groups 5 (CS90Indo30) and 6 (CS90Indo60). Intravital microscopy and fluorescent staining assessed capillary perfusion, cell damage, and inflammatory activation within extensor digitorum longus muscle. Apoptosis was assessed using spectrophotometric assessment of caspase levels. Groups 1 to 3 and 4 to 6 were compared using analysis of variance with P < 0.05 deemed significant. RESULTS: Perfusion and tissue viability improved in indomethacin-treated groups. Nonperfused capillaries decreased from Group 1 (CS45) (50.1 +/- 2.5) to Group 2 (CS45Indo0) (38.4 +/- 1.8) and Group 3 (CS45Indo30) (14.13 +/- 1.73) (P < 0.05). Similarly, Group 5 (CS90Indo30) and Group 6 (CS90Indo60) had 25% fewer nonperfused capillaries compared with Group 4 (CS90) (P < 0.0001). Group 2 (CS45Indo0) and Group 3 (CS45Indo30) showed fewer damaged cells (1% +/- 0.5% and 8.7% +/- 2%) compared with Group 1 (CS45) (20% +/- 14%) (P < 0.0001). Group 5 (CS90Indo30) showed decreased cell damage (13% +/- 1%) compared with Group 4 (CS90) (18% +/- 1%) (P < 0.01). Group 6 (CS90Indo60) also showed decreased cell damage (11% +/- 1%) compared with Group 4 (CS90) (18% +/- 1%); however, this difference was not significant (P > 0.05). Apoptotic activity was present with elevated intracompartment pressure. At 30 minutes, there were elevated caspase levels in Group 4 and Group 6 EICP groups (0.47 +/- 0.08) compared with control subjects (0.19 +/- 0.02) (P < 0.003). However, indomethacin-treated groups did not differ from control subjects with regard to caspase levels (P > 0.05). CONCLUSION: Indomethacin decreased cell damage and improved perfusion in elevated intracompartment pressure. The benefits of indomethacin were partially time-dependent; some improvement in tissue viability occurred regardless of timing of administration. Although apoptosis was common in elevated intracompartment pressure, the protective effect of indomethacin does not appear to be related to apoptosis. CLINICAL RELEVANCE: Adjuvant treatment with indomethacin may improve outcome in compartment syndrome.

Temporal bone fractures: a review for the oral and maxillofacial surgeon.

Fracture of the temporal bone is, by definition, a fracture of the skull base. Even though the oral and maxillofacial surgeon (OMS) may not provide definitive management of temporal bone fractures or their sequelae, a working knowledge of this area is important for any surgeon participating in the care of patients with craniomaxillofacial trauma, because temporal bone fractures are often associated with injuries to other areas of the craniomaxillofacial skeleton and because these fractures are relatively frequent. In many centers, particularly community hospitals, the OMS may be the primary provider of care for facial trauma and will treat patients with clinical or radiographic evidence of temporal bone fractures. Immediate access to other specialists to manage or observe these injuries may not be possible, making the OMS responsible for early evaluation and management. This article briefly reviews the epidemiology of temporal bone injuries, as well as the pertinent anatomy, radiographic imaging findings, and ancillary testing maneuvers. It then presents a more detailed description of the various clinical findings and the associated management strategies. It concludes with a discussion of the subset of temporal bone fractures involving the temporomandibular joint.