Comparison analysis of orbital shape and volume in unilateral fractured orbits.

Facial fractures often result in changes of the orbital volume. These changes can be measured in three-dimensional (3D) computed tomography (CT) scans for preoperative planning and postoperative evaluation. The aim of this study was to analyze the orbital volume and shape before and after surgical treatment of unilateral orbital fractures using semi-automatic image segmentation and registration techniques. The orbital volume in 21 patients was assessed by a semi-automatic model-based segmentation method. The fractured orbit was compared relative to the contralateral orbit. The same procedure was performed for the postoperative evaluation. Two observers performed the segmentation procedure, and the inter- and intraobserver variability was evaluated. The interobserver variability (mean volume difference ± 1.96 SD) was -0.6 ± 1.0 ml in the first trial and 0.7 ± 0.8 ml in the second trial. The intra-observer variability was -0.2 ± 0.7 ml for the first observer and 1.1 ± 0.9 ml for the second observer. The average volume overlap (Dice similarity coefficient) between the fractured and contralateral side increased after surgery, while the mean and maximum surface distance decreased, indicating that the surgery contributed to a re-establishment of size and shape. In conclusion, our study shows that the semi-automatic segmentation method has precision for detecting volume differences down to 1.0 ml. The combination of semi-automatic segmentation and 3D shape analysis provides a powerful tool for planning and evaluating treatment of orbital fractures.

Surgical pneumatization through maxillary sinus wall and the schneiderian membrane: A new technique to facilitate augmentation of the maxillary sinus.

A minimum subantral bone height in the posterior maxilla may require a bone augmentation where a sinus lift procedure is the most commonly used technique, either preceding or simultaneously with the implant installation. While elevating the Schneiderian membrane ruptures are common, possibly resulting in less bone formation. In this paper, we propose the surgical pneumatization of the Schneiderian membrane as a new technique to minimize the risk of such complications. This can be achieved mainly by creating a hole for the immediate and increased passage of air through the Schneiderian membrane and the maxillary sinus wall above the region of augmentation.

Surgical approach to snus-induced injury of the oral mucosa.

Snus (Swedish moist snuff) causes lesions in the oral mucosa at the location where pinches are regularly placed. In addition, some patients develop irreversible local gingival recession and sometimes ulcers with perforations to the roots. Such injuries lead to denuded roots that are at risk for caries and periodontal disease, with subsequent esthetic consequences. Therapy for irreversible local gingival recession is currently lacking. In the present report, we describe two cases of successful surgical treatment for irreversible lesions caused by snus.

Oral cancer in Swedish snuff dippers.

Over recent decades there has been debate over whether or not Swedish snuff is carcinogenic in humans. Animal studies and molecular biological and experimental studies have shown the carcinogenic potential of Swedish snuff, but this has not been proved in prospective randomized studies. We present a case series of patients with oral squamous cell carcinomas diagnosed at the sites where the patients had used Swedish snuff for several years. Sixteen male patients were referred to and treated at Oral and Maxillofacial Surgery Departments and Ear, Nose and Throat clinics at seven different hospitals in Sweden. The mean age of the patients at the time of diagnosis was 72.9 years and the mean time of snuff use prior to cancer diagnosis was 42.9 years. This case series shows that Swedish snuff may not be a harmless alternative to smoking.