Visualization of the Inferior Alveolar Nerve and Lingual Nerve Using MRI in Oral and Maxillofacial Surgery: A Systematic Review.

We evaluate the preoperative visualization of the inferior alveolar nerve (IAN) and lingual nerve (LN) as reported using radiation-free magnetic resonance imaging (MRI). An accurate visualization shall minimize the postoperative risk for nerve injuries in oral and maxillofacial surgery. PubMed MEDLINE, EMBASE, Biosis, and Cochrane databases were selected for the PICOS search strategy by two reviewers using medical subject headings (MeSH) terms. Thirty studies were included in the systematic review. Based on these studies' findings, the use of black bone MRI sequences, especially 3D short-tau inversion recovery (STIR), provides superior soft-tissue resolution and high sensitivity in detecting pathological changes. Due to the implementation variability regarding scan parameters and the use of different magnetic field strengths, studies with well-designed protocols and a low risk of bias should be conducted to obtain stronger evidence. With improved cost and time efficiency and considering the benefit-risk ratio, MRI is a promising imaging modality that could become part of routine clinical practice in the future.

Customized Titanium Reconstruction of Orbital Fractures Using a Mirroring Technique for Virtual Reconstruction and 3D Model Printing.

PURPOSE: Early operative reconstruction using titanium mesh is a technique often used for preventing sequelae after an orbital fracture. We sought to examine the utility of patient-specific molding of the mesh with a biomodel via virtual mirroring of the nonaffected side. METHODS: We retrospectively assessed the clinical and radiological outcomes of orbital fracture reconstruction using a customized titanium mesh shaped on 3D-printed biomodels in 34 unilateral orbital fracture cases. Preoperative virtual orbital reconstruction images, using the mirroring technique, were superimposed on postoperative 3D images, and clinical data from patient charts were analyzed. Orbital reconstructions were rated, and the intention to revise results intraoperatively, or during inpatient or outpatient phases, was assessed by 2 consultants and 2 residents. RESULTS: We found that most fractures arose from falls of <3 meters or from interpersonal violence. Ophthalmic injuries included subconjunctival bleeding, ocular contusion, enophthalmos, and diplopia. Long-term sequelae at last followup were diplopia (8.8%) and mild enophthalmos (11.8%). CONCLUSION: Interrater reliabilities regarding consultants' intention to revise results were substantial to almost perfect at any time point. Therefore, using the mirroring technique for the virtual reconstruction of a fractured orbit and a 3D-printed biomodel to customize commercial titanium implants yields good and reliable results, enhances surgical precision, and decreases the need for intraoperative revision, as well as long-term sequelae of orbital fractures.

Anatomic (positional) variation of maxillary wisdom teeth with special regard to the maxillary sinus.

The removal of wisdom teeth is one of the most common interventions in oral surgery. In order to avoid complications, a profound knowledge of the anatomy of teeth and adjacent tissues is crucial. In the case of maxillary wisdom teeth, their relationship to the maxillary sinus, to the pterygoid fossa, to the maxillary tuber and the adjacent venous plexus is particularly important. Three-dimensional (3D) imaging, for example by means of cone beam computed tomography (CBCT), is increasingly utilized in practice. However, the necessity of CBCT imaging is still a matter of intensive debate. The aim of this study was to describe the anatomic (positional) variation of maxillary wisdom teeth and, based on these findings, to elucidate the additional benefit of such imaging. A retrospective case study was performed using patients examined by means of CBCT imaging in the Department of Dento-Maxillofacial Radiology during the period from 2008 to 2013. Primary study variables comprised the spatial relationship of the teeth to the maxillary sinus, the degree of retention and root development, the covering of the root with bone and mucosa, the root configuration, and the developmental stage of the tooth. In addition, the association of the inclination of teeth in the transversal and sagittal plane with the above variables was evaluated. Descriptive statistical parameters were calculated for all results of the examination. In total, CBCT recordings of 713 maxillary wisdom teeth from 430 patients were evaluated. Their mean age was 29.8 years, and the proportion of male patients slightly prevailed (54.4%). Most teeth exhibited fully developed roots (64.1%). Overall 22.9% of third molars were impacted, 32.3% were retained, and 6.5% were erupting. In more than a third of the patients, wisdom teeth were in occlusion. The inclination of the third molars both in the transversal and sagittal plane was significantly associated with the distance of the root from the maxillary sinus as well as with the bony covering of the root. Owing to the possibility of evaluating preoperatively the relationship of a wisdom tooth to the maxillary sinus and to other anatomic structures, we recommend the use of CBCT, whenever conventional radiography fails to provide adequate information about the critical anatomic circumstances of maxillary third molars. However, CBCT should, at least nowadays, not be utilized as the standard radiographic examination.