Analysis and comparison of clinical results of bilateral sagittal split ramus osteotomy performed with the use of monocortical locking plate fixation or bicortical screw fixation.

OBJECTIVE: The aim of this study was to compare clinical results of bilateral sagittal split ramus osteotomy (BSSRO) with the use of monocortical locking plate or bicortical screw fixation. STUDY DESIGN: Fifty-five patients underwent BSSRO for prognathism, using either monocortical locking plate (group A; n = 28) or bicortical screw (group B; n = 27) osseofixation. No intermaxillary fixation was done after surgery. Groups were subdivided according to presence or absence of mandibular asymmetry. Time course changes in condylar and skeletal stability were measured on lateral and posteroanterior cephalograms and axial radiographs before surgery and at 3 and 6 months after surgery. RESULTS: In facial symmetry subjects, the change in angle of the longitudinal axis of the condyle in group A was significantly greater than that for group B up to 3 months after surgery, but no significant differences were found in facial asymmetry subjects. CONCLUSIONS: The findings of this study suggest that monocortical fixation using the locking plate system to stabilize SSRO is as reliable as bicortical screw fixation regardless of facial asymmetry.

Effect of recombinant human fibroblast growth factor-2 on bone formation in rabbit mandibular distraction models using beta-tricalcium phosphate.

This study was designed to evaluate the effect of recombinant human fibroblast growth factor-2 (rhFGF-2) on the amount and period of new bone formation in rabbit mandibular distraction models using beta-tricalcium phosphate (beta-TCP) as a bone graft substitute. Sixteen male Japanese White rabbits were divided into the following four experimental groups: 1, distraction alone; 2, distraction with beta-TCP granules; 3, distraction with rhFGF-2 (25 microg/50 microL) injected into beta-TCP granules; and 4, distraction with rhFGF-2 (100 microg/50 microL) injected into beta-TCP granules. The bones were harvested at 4 weeks after the operation and examined using soft radiography, micro-computed tomography (micro-CT), and peripheral quantitative computed tomography (pQCT). The dissected mandibles were stained using the Villanueva bone staining method, and the amount of new bone formed, bioresorption of beta-TCP, and new blood vessel formation were morphometrically calculated using bone histomorphometry. Radiopaque areas were observed more frequently in the distracted area of groups 3 and 4. Micro-CT analysis revealed partial new bone formation in the central region of the distracted area in groups 3 and 4. pQCT analysis revealed increased bone mineral density in groups 3 and 4. Histomorphometric analysis revealed increased newly formed bone and blood vessel areas in groups 3 and 4. In group 4, the number of osteoclasts around the beta-TCP granules had significantly increased. The present findings suggested that the combined use of rhFGF-2 and beta-TCP reduced the treatment period for distraction osteogenesis and accelerated the formation of a new high-quality bone.

Accuracy and reliability of thermal threshold measurement in the chin using heat flux technique.

BACKGROUND: Neurosensory disturbance (NSD) occasionally develops in the chin following dental treatments, and evaluation of the involved nerve damage is important for treatment. The thermal-threshold test is a method of evaluating nerve sensations, but it is not widely used because its accuracy and reliability have not yet been determined. PURPOSE: This study aimed to determine the accuracy and reliability of thermal-threshold measurement of the chin by using the heat-flux technique. MATERIALS AND METHODS: The subjects were 19 healthy volunteers (7 women, 12 men), aged 21 to 36 years (mean age +/- SD, 27.2 +/- 4.5 years). The thermal thresholds, including the warm and cold heat-flux thresholds (WHF and CHF, respectively) were measured on the chin, forehead, and neck by using a thermostimulator. To evaluate test-retest reliability, we measured the thermal thresholds on 3 different days (days 1, 3, and 7). RESULTS: The WHF and CHF of the right chin were 460 +/- 165 W/m(2) (mean +/- SD W/m(2)) and 589 +/- 133 W/m(2), respectively, and those of the left chin were 446 +/- 112 W/m(2) and 576 +/- 147 W/m(2), respectively. The thermal thresholds of the right and left chin were significantly correlated (R = 0.89, P < .001). Thermal-threshold measurement was more accurate in the case of the chin than in the case of the neck. The thermal thresholds measured over the 3 days varied very little (intraclass correlation coefficient, 0.80-0.81), indicating high test-retest reliability. CONCLUSION: The heat-flux technique is accurate and highly reliable. Therefore, it may be a useful method for determining the thermal threshold of the chin.

Analysis of clinical usefulness of the heat flux technique: predictability of the recovery from neurosensory disturbances in the chin undergoing mandibular sagittal split ramus osteotomy.

OBJECTIVE: To examine the prognosis of the neurosensory disturbance (NSD) in the chin after bilateral sagittal split ramus osteotomy (BSSRO), using the heat flux technique. STUDY DESIGN: Twenty-nine patients (total 58 sides) undergoing BSSRO were examined. The warm sensory threshold (WHF) and cold sensory threshold (CHF) in the chins of these patients were measured by the heat flux technique. Touch sensory threshold (TS) was measured by an Semmes-Weinstein esthesiometer. Touch sensory disturbance was subjectively evaluated by visual analog scale. RESULTS: At all of the postoperative time points, there were no significant differences in the incidence rate among all tests (chi-squared test; P > .05). WHF, CHF, and TS were significantly correlated with the subjective evaluation. Recovery from NSD was delayed in cases that the postoperative variation of 2 weeks was >400 W/m(2) in WHF and CHF and the filament marking at 2 weeks after surgery was >3.5 in TS. CONCLUSION: The heat flux technique appears to be a useful method for the prediction of the recovery from NSD in the chin.

A male infant case of lipofibromatosis in the submental region exhibited the expression of the connective tissue growth factor.

PURPOSE: We encountered a case of lipofibromatosis in a 21-month-old male patient and examined its histopathologic properties. METHODS: We examined morphological aspects of the tumor and immunohistochemical patterns. RESULTS: Tumor proliferation was infiltrative, which did not show apparent encapsulation. Positive immunoreactivity was found for CD-34, CD-99, Ki-67, and connective tissue growth factor/CCN2 in the fibrous region, S-100 in the adipose region, and Notch1 stain was observed in the eccrine sweat gland cells juxtaposed to the tumor adipose tissue, but no reactivity for Bcl-2, alphaSMA, Notch 2-4, CCN1, and CCN3. CONCLUSIONS: The clinical process and immunohistochemical pattern of this case was consistent with the criteria of reported lipofibromatosis. Specific expression of CCN2 might be significant for the development of the tumor.

A new evaluation method for neurosensory disturbance in the chin of patients undergoing mandibular sagittal split ramus osteotomy: an application of the heat flux technique.

OBJECTIVE: To examine neurosensory changes in the chin following bilateral sagittal split ramus osteotomy (BSSRO) using the heat flux technique. STUDY DESIGN: Twelve healthy adults (C-group) and 23 patients undergoing BSSRO (P-group) were examined. The warm sense threshold (WHF) and cold sense threshold (CHF) in the chin of these patients were measured by the heat flux technique. In the P-group, touch sensation also was measured with a visual analog scale (VAS) and the Semmes-Weinstein monofilament test (SW test). RESULTS: Both WHF and CHF were significantly larger in the P-group than in the C-group (P = .024). Touch sensation (VAS and SW test) were damaged in some patients of the P-group. However, no correlation was revealed between thermal sensation (WHF and CHF) and touch sensation (VAS and SW test) in the P-group. CONCLUSIONS: These results suggest that the thermal sensation in the chin was damaged after BSSRO. The heat flux technique appears to be one of the useful methods for the examination of neurosensory disturbance in the chin.

Administration of parathyroid hormone, prostaglandin E2, or 1-alpha,25-dihydroxyvitamin D3 restores the bone inductive activity of rhBMP-2 in aged rats.

Bone morphogenetic protein (BMP) induces bone formation in young rodents, but aging causes a reduction in the bone-forming ability of BMP. Most patients who require bone reconstruction are relatively old. Accordingly, we examined whether anabolic hormones could restore the bone inductive activity of rhBMP-2 in aged rats. rhBMP-2 in a carrier pellet was implanted subcutaneously in both 4- and 50-week-old female Wistar rats. PTH, PGE2, or 1,25(OH)2D3 was injected every day during the period of BMP implantation. The pellets were harvested, and were examined both histologically and biochemically 2 weeks after implantation. Bone-forming ability was measured by alkaline phosphatase (ALP) activity and calcium (Ca) content. Pellets in 50-week-old rats showed a significant reduction in bone formation compared to pellets in 4-week-old rats. However, daily injections of PTH into 50-week-old rats restored both ALP activity (103 +/- 4.6%) and Ca content (105 +/- 2.6%). 1,25(OH)2D3 and PGE2 also restored Ca content (103 +/- 4.5% and 98 +/- 3.8%, respectively) and stimulated ALP activity (142 +/- 2.3% and 133 +/- 3.6%). These results show that the administration of these hormones restores bone-forming ability in aged rats. A combination treatment of these hormones with rhBMP-2 might be applicable to the reconstruction of bone defects in elderly patients.