Accuracy of palatal orthodontic mini-implants placed by conventionally or CAD/CAM-based surgical guides: a comparative in vitro study.

OBJECTIVES: To investigate and compare the transfer accuracy of five different surgical guides (SGs) for the insertion of orthodontic mini-implants (OMIs) in the anterior palate. MATERIALS AND METHODS: Stereolithographic files of 10 maxillary patient models and their corresponding lateral cephalograms were virtually matched and used for planning the position of two parallel OMIs in the paramedian region of the anterior palate. For each patient model, three 3-dimensional (3D)-printed and two conventional SGs were manufactured from different materials, and a total of 96 OMIs were transferred to the anterior palates of the respective 50 molded resin models. The planned (T0) and the actual (T1) OMI positions were analyzed and compared after superimposition of the digitized models. The deviations between the OMI positions in T0 and T1 were described as the distance between the head and the tip, respectively, of each OMI in millimeters and the deviating angle between the OMI axes for each patient and SG. RESULTS: The conventionally manufactured SGs of Pattern Resin LS (GC Europe N.V., Leuven, Belgium) showed the highest linear and angular transfer accuracy for the insertion of OMIs. The highest deviations were found with the SGs made of IMPRIMO LC Splint (3D-printed; Scheu-Dental, Iserlohn, Germany) and Memosil 2 (conventional SG; Kulzer, Hanau, Germany). CONCLUSIONS: The 3D-printed SGs did not reach the accuracy of the conventional SGs made of Pattern Resin but may provide sufficient accuracy for palatal OMI placement.

Upregulation of PD-L1 and PD-L2 in neck node metastases of head and neck squamous cell carcinoma.

BACKGROUND: This study aimed on evaluating the expression levels of the immune checkpoint proteins, PD-L1 and PD-L2, in tissue specimens of 175 oral squamous cell carcinomas (OSCC) and 33 corresponding lymph node metastases (LNM). METHODS: Tissue microarrays of primary OSCC and matched LNM were investigated via immunohistochemistry regarding PD-L1/PD-L2 expression. Results were compared for primary tumors and corresponding metastases and correlated with clinicopathological data. RESULTS: PD-L1 expression in cancer cells correlated significantly with tumor size, and the presence of regional metastases (P < 0.01). PD-L1 expression was significantly higher in metastases as compared to primary OSCC (P < 0.05). Overall survival was significantly worse in patients with higher levels of PD-L1 and PD-L2 score (P < 0.05). CONCLUSIONS: This is the first publication to compare PD-L1 and PD-L2 expression in primary OSCC and matched LNM. The results indicate that anti-PD-1 therapy may be of therapeutic use even in early stage OSCC to prevent further progression.