The use of patient specific polyetheretherketone implants for reconstruction of maxillofacial deformities.

PURPOSE: The aim of this study was to evaluate polyetheretherketone (PEEK) as a patient-specific implant (PSI) material in maxillofacial reconstructive surgery. MATERIALS AND METHODS: The retrospective study included a cohort of 24 patients who underwent maxillofacial surgery using PEEK PSIs. Each patient underwent preoperative multislice computed tomography (CT) with 0° tilt of gantry. Based on the CT scan, the PEEK PSIs were planned and manufactured using three-dimensional (3D) modeling and computer-aided design/computer-aided manufacturing (CAD/CAM) techniques. All procedures were performed under general anesthesia. Implants were placed intraorally, extraorally or through subciliary, transconjuctival or coronal incisions. RESULTS: In 22 of 24 cases, the PEEK PSI fit well without adjustments. Although the fit to the surrounding bone was perfect in almost all of the cases, the outer contour of the PSI was modified in nine cases before fixation. However, intraoperative implant modification did not affect the infection rate. In two cases, postoperative wound dehiscence and infection needed additional treatment and healed without removal of the implants. CONCLUSION: The follow-up data in this study showed good outcomes with reliable results for PSI made of PEEK in the maxillofacial region.

Lactational exposure of Han/Wistar rats to 2,3,7,8-tetrachlorodibenzo-p-dioxin interferes with enamel maturation and retards dentin mineralization.

Exposure to environmental dioxins via mother's milk may be one causative factor of mineralization defects in children's teeth. A prerequisite for the completion of enamel mineralization is the removal of enamel matrix. To test the hypothesis that dioxins interfere with enamel maturation, we administered lactating Han/Wistar rats a single dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 50 or 1000 micro g/kg) on the day after delivery and analyzed tissue sections of the pup heads at post-natal days (Pn) 9 and 22. By Pn22, the first and second molars of the exposed pups, but not controls, showed retention of enamel matrix. Predentin was thicker than normal. Immunostaining for the aryl hydrocarbon/dioxin receptor (AhR) and cytochrome P4501A1 (CYP1A1) in ameloblasts and odontoblasts was reduced, suggesting that TCDD interferes with tooth mineralization via AhR. Extinction of AhR may lead to abolition of CYP1A1 expression as a sign of impaired dental cell function.