3D Printed Surgical Simulation Models as educational tool by maxillofacial surgeons.

INTRODUCTION: The aim of this study was to evaluate whether inexpensive 3D models can be suitable to train surgical skills to dental students or oral and maxillofacial surgery residents. Furthermore, we wanted to know which of the most common filament materials, acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA), can better simulate human bone according to surgeons' subjective perceptions. MATERIALS AND METHODS: Upper and lower jaw models were produced with common 3D desktop printers, ABS and PLA filament and silicon rubber for soft tissue simulation. Those models were given to 10 blinded, experienced maxillofacial surgeons to perform sinus lift and wisdom teeth extraction. Evaluation was made using a questionnaire. RESULTS: Because of slightly different density and filament prices, each silicon-covered model costs between 1.40-1.60 USD (ABS) and 1.80-2.00 USD (PLA) based on 2017 material costs. Ten experienced raters took part in the study. All raters deemed the models suitable for surgical education. No significant differences between ABS and PLA were found, with both having distinct advantages. CONCLUSION: The study demonstrated that 3D printing with inexpensive printing filaments is a promising method for training oral and maxillofacial surgery residents or dental students in selected surgical procedures. With a simple and cost-efficient manufacturing process, models of actual patient cases can be produced on a small scale, simulating many kinds of surgical procedures.

Traumatology of the facial skeleton in octogenarian patients: a retrospective analysis of 96 cases.

AIM: The aim of this retrospective study was to evaluate the frequency and distribution of maxillofacial trauma patients over 80 years, with regard to type and environment of accidents as well as treatment and complications. PATIENTS AND METHODS: Data for 94 patients (96 cases; aged 80-94 years) with maxillofacial fractures were retrospectively analysed. RESULTS: Data of 30 male and 64 female patients with an average age of 85 years were analysed. In 90% of the study population, the cause of fractures was a fall, followed by traffic accidents (9%) and assault (1%). Seventy-two patients had fractures of the midface, 10 had factures of the mandible, 9 had fractures of both the midface and mandible and 5 had fractures of the neurocranium and midface. Surgical intervention was required in 57% of the patients. Post-operative complications were: four cases of diplopia, two cases of infected plates, four cases of lower eyelid ectropion and in one case a retrobulbar haematoma. CONCLUSION: Facial trauma in the elderly can often be treated conservatively unless the patient complains of functional problems. Due to co-morbidities, special attention should be paid to hypertension, anticoagulant agents and the surgical approach.

Do we need real-time MRI for diagnosis of temporomandibular joint disorders?

INTRODUCTION: Magnetic resonance imaging (MRI) has been approved as an appropriate radiological modality for temporomandibular joint (TMJ) diagnosis, whereas the results of international multicenter studies impressively show the limitations of static three-dimensional MRI. The state of the art for dynamic imaging of the TMJ in real-time are TrueFISP sequences in one sagittal plane. In order to support the diagnostics, a computer-assisted visualization procedure has been developed by the authors for both the static and dynamic MRI. METHODS: A number of validated sequences are available for the static 3D-MRI within the clinical routine. For dynamic MRI in real-time, True-FISP sequences in one sagittal plane with a slice thickness of 5-10 mm and 1.3 mm x 1.3 mm spatial resolution were applied. Both the dynamic and static MRI datasets are animated and visualized using the computer-assisted procedure. RESULTS: The computer-assisted procedure reliably supported the clinical diagnosis, especially the visibility of the articular disc was enhanced. On the basis of the static MRI, a 60-year-old patient was diagnosed with anterior disc displacement without reduction. In contrast, by the dynamic MRI, it was recognized how the articular disc was firstly somehow stretched and flattened before the mandibular condyle again glided under the disc, thus resulting in an anterior disc displacement with reduction. CONCLUSION: These results endorse the relevance of real-time diagnosis for the TMJ. The computer-assisted visualization has been approved as a reliable help for clinical diagnosis.