Biopsies of osseous jaw lesions using 3D-printed surgical guides: a clinical study.

BACKGROUND: Bone biopsies are often necessary to make a diagnosis in the case of irregular bone structures of the jaw. A 3D-printed surgical guide may be a helpful tool for enhancing the accuracy of the biopsy and for ensuring that the tissue of interest is precisely removed for examination. This study was conducted to compare the accuracy of biopsies performed with 3D-printed surgical guides to that of free-handed biopsies. METHODS: Computed tomography scans were performed on patients with bony lesions of the lower jaw. Surgical guides were planned via computer-aided design and manufactured by a 3D-printer. Biopsies were performed with the surgical guides. Bone models of the lower jaw with geometries identical to the patients' lower jaws were produced using a 3D-printer. The jaw models were fitted into a phantom head model and free-handed biopsies were taken as controls. The accuracy of the biopsies was evaluated by comparing the parameters for the axis, angle and depth of the biopsies to the planned parameters. RESULTS: Eight patients were included. The mean deviation between the biopsy axes was significantly lower in guided procedures than in free-handed biopsies (1.4 mm ± 0.9 mm; 3.6 mm ± 1.0 mm; p = 0.0005). The mean biopsy angle deviation was also significantly lower in guided biopsies than in free-handed biopsies (6.8° ± 4.0; 15.4° ± 3.6; p = 0.0005). The biopsy depth showed no significant difference between the guided and the free-handed biopsies. CONCLUSIONS: Computer-guided biopsies allow significantly higher accuracy than free-handed procedures.

In-house 3D-printed surgical guides for osseous lesions of the lower jaw: an experimental study.

BACKGROUND: The accuracy of computer-assisted biopsies at the lower jaw was compared to the accuracy of freehand biopsies. METHODS: Patients with a bony lesion of the lower jaw with an indication for biopsy were prospectively enrolled. Two customized bone models per patient were produced using a 3D printer. The models of the lower jaw were fitted into a phantom head model to simulate operation room conditions. Biopsies for the study group were taken by means of surgical guides and freehand biopsies were performed for the control group. RESULTS: The deviation of the biopsy axes from the planning was significantly less when using templates. It turned out to be 1.3 ± 0.6 mm for the biopsies with a surgical guide and 3.9 ± 1.1 mm for the freehand biopsies. CONCLUSIONS: Surgical guides allow significantly higher accuracy of biopsies. The preliminary results are promising, but clinical evaluation is necessary.

Edentulous mandible with four splinted interforaminal implants exposed to three different situations of trauma: A preliminary three-dimensional finite element analysis.

BACKGROUND/AIM: An increasing number of elderly patients with implant-prosthodontic rehabilitation of the edentulous mandible frequently show increased life activity, and consequently, a greater number of aged patients is at risk for maxillofacial trauma. The aim of this 3-dimensional (3D) finite element analysis (FEA) was to evaluate the biomechanical effects of the edentulous mandible (EM) with and without four splinted interforaminal implants exposed to three different trauma applications including assessment of different mandibular fracture risk areas. MATERIALS AND METHODS: In a 3D-FEA study design, EM with and without four splinted interforaminal implants were exposed to the application of 1000 N at the symphyseal, parasymphyseal, and mandibular angle region. On four pre-defined superficial cortical mandibular areas (symphysis region, mental foramen region, angle of mandible, and mandibular neck) representing regions of interest (ROI), the von Mises stresses were measured for the three trauma applications. For all ROIs, stress values were evaluated and compared for the different force application sites as well as between EM models with and without interforaminal implants. RESULTS: For EM with and without four splinted interformaninal implants, all traumatic loads generated the highest stress levels at the mandibular neck region. However, in the EM with four splinted interforaminal implants, an anterior symphyseal force application generated significantly (P < .01) increased stress values in the parasymphyseal (mental foramen) region than in EM without implants. For force applications at the parasymphaseal region (mental foramen) and at the angle of the mandible elevated, von Mises stress values were noted directly at the application sites without difference between edentulous mandibles with and without four interforaminal implants. CONCLUSION: In an edentulous mandible model with four splinted interforaminal implants, the condylar neck and the mental foramen represent the predilectional risk areas for mandibular fracture for both anterior symphyseal and lateral parasymphyseal force application.