Condylar degeneration in anterior open bite patients: A cone beam computed tomography study.

OBJECTIVES: The purpose of this study was to investigate the prevalence of condylar degeneration in patients with anterior open bites (AOB). STUDY DESIGN: Cone beam computed tomography (CBCT) scans of 194 patients with AOB (108 with skeletal open bites and 86 with dental open bites) and 100 patients serving as controls were included in this retrospective study. Two oral and maxillofacial radiologists categorized each of the 588 condyles as normal, degenerative-active, or degenerative-repair. The χ2 analysis with Bonferroni adjustment was used to evaluate the relationship of condylar status (normal vs degenerative) to anterior open bites. RESULTS: Of the 103 degenerative condyles, there were 59 in the group with skeletal open bites, 14 in the group with dental open bites, and 30 in the control group. Condylar degeneration occurred twice as frequently in patients with skeletal open bites as it did in the control group (P < .0001). Conversely, a greater frequency of normal condyles was found in the group of patients with dental open bites (P = .0002). The group with skeletal open bites also showed a significantly higher frequency of bilateral degenerative condyles (P = .0001). The frequency of condylar degeneration did not differ significantly between female and male individuals. CONCLUSIONS: Degenerative condylar change was significantly more likely in patients with skeletal open bites and less likely in patients with dental open bites.

Mechanical allodynia induced by traumatic brain injury is independent of restraint stress.

BACKGROUND: This study identifies the relationship between a test for post-traumatic headache and a marker for acute stress in rodent models of traumatic brain injury. NEW METHOD: C57BL/6 mice and Sprague Dawley rats were divided into Controlled Cortical Impact (CCI) injury, craniotomy (CR), and incision groups. Periorbital and paw allodynia were evaluated using the von Frey test prior to injury and up to four weeks post-operatively. Serum corticosterone was evaluated in groups with and without mild restraint. RESULTS: Periorbital and forepaw thresholds, but not hindpaw thresholds, were reduced in CCI and CR mice compared to incision (p<0.0001 and p<0.01). In contrast to mice, reduced periorbital and forepaw periorbital thresholds were found in CCI rats but not CR rats compared to incision (p<0.0001). Right periorbital thresholds were reduced compared to left thresholds for both rat and mouse at one week (p<0.01), but there were no side differences for forepaw thresholds. Hindpaw thresholds did not change from baseline values for any groups of mice or rats. In mice serum corticosterone levels were increased at one, two and four weeks post-CCI and CR, while the levels for rats were not different from incision (p<0.0001). Corticosterone levels were not different in mice subjected to restraint compared to no restraint. COMPARISON WITH EXISTING METHODS: This study presents novel data for allodynia in a rat model of TBI, and differences among mouse and rat species. CONCLUSIONS: Mechanical allodynia occurs independent of evoked restraint stress, while hypothalamic pituitary adrenal axis activity is dependent on head trauma and species.