Development of a three-dimensional treatment planning system based on computed tomographic data.

Current surgical treatment planning systems predict three-dimensional (3D) corrections from two-dimensional (2D) data and are inadequate for complex movements. In this paper, we present a 3D planning system based on computed tomographic (CT) data. A three-dimensional CT scan of the craniofacial skeleton forms the database. Software developed in the Harvard Surgical Planning Laboratory was modified for the craniofacial skeleton. Reproducible skeletal landmarks are identified for superimposition. A 'cutting tool' is used to segment the mandible and segments are moved to their predicted positions. A 'collision tool', alerts the operator of skeletal interferences. An analysis of selected scans is used to demonstrate the system. Three-dimensional visualization of the facial skeleton, selection of landmarks, measurement of angles and distances, simulation of osteotomies, repositioning of bones, detection of collisions and super-imposition of scans were accomplished. In an illustrative case of Hemifacial Microsomia, predicted and actual 3D corrective movements of the entire mandible were documented. Analysis of scans indicated that 3D planning can prevent insufficient jaw lengthening or other surgical inaccuracies which occur with standard 2D methods. Software demonstrated here will allow the surgeon to accurately plan treatment and evaluate craniomaxillofacial surgery outcomes. Future applications may include surgical navigation.

Evaluation of a semiburied, fixed-trajectory, curvilinear, distraction device in an animal model.

PURPOSE: This study evaluated a new small, buried distractor, capable of curvilinear movement while following a fixed trajectory. The geometrical basis for such devices and the 3-dimensional treatment planning system required to make buried distractors practical are discussed. MATERIALS AND METHODS: A curved rack and worm-gear device, based on the design of a hose clamp, was constructed to produce a curved distraction path, and this distractor was tested in 2 minipigs using a protocol with zero latency and 1 mm/d x 7 days of distraction. Serial standardized lateral cephalograms were used to verify distractor function and path. RESULTS: Curvilinear distraction was documented by clinical examination and serial cephalometric analysis in the 2 minipigs. Observed angulation of the margins of the wedge-shaped distraction gap conformed to the calculated angulation based on the fixed radius of curvature of the distractor. CONCLUSION: Distraction along a curved trajectory using a small, semiburied, curvilinear device of novel design is feasible in the minipig mandible.

A clinical trial in oral surgery of the analgesic efficacy of a suprofen/codeine combination.

Suprofen as well as codeine have been shown to be effective analgesics. In this study, a 200-mg suprofen/60-mg codeine dose is scored for analgesic efficacy and safety compared to suprofen (200 mg), codeine (60 mg), and placebo. One hundred sixty-five healthy, adult patients were asked to rate degree of pain experienced over a six-hour period after medication. The combination treatment was found to offer maximum pain relief. Dentists should be aware that flank pain and renal function abnormalities have been reported in postmarketing surveillance.

Analgesic regimens for third molar surgery: pharmacologic and behavioral considerations.

The level of pain following the extraction of impacted third molars was evaluated in 75 patients. Participants were administered acetaminophen 1,000 mg or a placebo before surgery. After surgery, acetaminophen 650 mg was administered either at fixed intervals or as needed to relieve pain. When acetaminophen was administered before surgery, the onset of peak pain was delayed and patient discomfort was decreased 3, 4, and 5 hours after surgery. Patients following the fixed interval regimen after surgery experienced more pain overall and requested the backup narcotic analgesic more frequently. Of the regimens tested, patients preferred the regimen of acetaminophen 1,000 mg administered before surgery with acetaminophen administered as needed for pain after surgery.

Mandibular fracture fixation and reconstruction using the lower-border threaded rod: an eleven-year follow-up study.

Twenty-five cases in which a lower border threaded rod was used for fracture fixation and mandibular reconstruction were reviewed. These cases were performed during the last 11 years and have been followed for periods of up to five years and ten months. The fixation technique, originally reported in 1978, is well tolerated and provides excellent mechanical stability when enhanced security of fixation is indicated. Three unusual cases are reported in detail.

A computer-assisted system for reporting of dental radiographs.

A computer reporting system in radiology at the Massachusetts General Hospital (MGH) uses the direct transcription of dictated reports into the computer with the option of standard reports. This article describes a system in regular use at MGH for reporting dental radiographs in which both the clinical history and the radiographic findings are assembled from canned subunits of standard text. The system covers 80 to 90 percent of all dental radiographs and results in a clear report requiring far less production time than previously.