Effect of self-setting α-tricalcium phosphate between segments for bone healing and hypoaesthesia in lower lip after sagittal split ramus osteotomy.

AIMS: The aim of this study was to evaluate hypoaesthesia of the lower lip and bone formation using self-setting α-tricalcium phosphate (Biopex(®)) between the proximal and distal segments following sagittal split ramus osteotomy (SSRO) with bent absorbable plate fixation. SUBJECTS AND METHODS: The subjects were 40 patients (80 sides) who underwent bilateral SSRO setback surgery. They were divided into a Biopex(®) group (40 sides) and a control group (40 sides). The Biopex(®) was inserted into the anterior part of the gap between the segments in the Biopex(®) group. Trigeminal nerve hypoaesthesia in the region of the lower lip was assessed bilaterally using the trigeminal somatosensory-evoked potential (TSEP) method. Ramus square, ramus length, and ramus width, the square of the Biopex(®) at the horizontal plane under the mandibular foramen were assessed preoperatively, immediately after surgery, and 1year postoperatively by computed tomography (CT). RESULTS: The mean measurable period and standard deviation were 9.3±15.7weeks in the control group, 5.3±8.3weeks in the Biopex(®) group, and there was no significant difference. Ramus square after 1year was significantly larger than that prior to surgery and new bone formation was found between the segments in both groups (P<0.05). In the Biopex(®) group, the square of the Biopex(®) after 1year was significantly smaller than that immediately after surgery (P<0.05). CONCLUSION: This study suggested that inserting Biopex(®) in the gap between the proximal and distal segments was useful for new bone formation and it did not prevent the recovery of lower lip hypoaesthesia after SSRO with bent absorbable plate fixation.

Bone healing of critical-sized nasal defects in rabbits by statins in two different carriers.

OBJECTIVES: To evaluate bone healing following implantation of a statin with two different carriers in rabbit nasal bone using histological and immunohistochemical methods. MATERIALS AND METHODS: Twenty adult, male Japanese white rabbits (age: 12-16 weeks, weight: 2.5-3 kg) were used in this study. Five bone circular defects (5 mm in diameter) per rabbit were created in the nasal bone while preserving the nasal membrane. In the experimental groups, 2.5 mg/ml simvastatin dissolved in 0.2 ml water with hydrogel was implanted in one group, 2.5 mg/ml simvastatin dissolved in 0.2 ml water with an atelocollagen sponge (ACS) in the second group with, only the hydrogel in the third group and only an ACS in the fourth group. No material was implanted in the control group. Four animals were killed in each period, at 1, 2, 4, 8 and 12 weeks postoperatively. The parts that had been operated on were removed and prepared for histological assessment. The expression of bone morphogenetic proteins (BMP)-2 and the bone ration was evaluated using histological and immunohistochemical methods. RESULTS: No significant differences were observed between the simvastatin with hydrogel group and the simvastatin with ACS group at 1, 2, 4, 8 and 12 weeks postoperatively regarding expression of BMP-2, although the number of cells that stained positive for BMP-2 in both of the implanted groups increased significantly at 2 and 4 weeks postoperatively in comparison with the control group (P<0.0001). For new bone area ratio, there were no significant differences between the simvastatin with hydrogel groups and the simvastatin with ACS group after 2, 4, 8 and 12 weeks, although these groups showed higher value than control group (P<0.0001). CONCLUSION: This study suggests that both the simvastatin with hydrogel and simvastatin with ACS implants showed similar BMP-2 expression and new bone formation, and there were no significant differences between the two carriers.

Skeletal stability after mandibular setback surgery: comparisons among unsintered hydroxyapatite/poly-L-lactic acid plate, poly-L-lactic acid plate, and titanium plate.

PURPOSE: The purpose of this study is to compare the time-course changes in condylar long-axis and skeletal stability after sagittal split ramus osteotomy (SSRO) with an unsintered hydroxyapatite (u-HA)/poly-L-lactic acid (PLLA) plate, PLLA plate, or titanium plate. PATIENTS AND METHODS: Of 60 Japanese patients diagnosed with mandibular prognathism, 20 underwent SSRO with a u-HA/PLLA plate system, 20 underwent SSRO with a PLLA plate system, and 20 underwent SSRO with a conventional titanium plate system. The time-course changes in condylar long-axis and skeletal stability were assessed by use of axial, frontal, and lateral cephalograms. RESULTS: Compared with the u-HA/PLLA group, the titanium group showed a significantly greater change in the right condyle angle between initially and 1 month (P = .0105) and intercondylar axes angle between 1 and 3 months (P = .0013). The PLLA group showed a significantly greater change than the titanium group (P = .0043) and u-HA/PLLA group (P = .0002) in terms of ramus inclination between 1 and 3 months; however, there were no significant differences among the 3 groups in the other measurements for each time interval. CONCLUSION: This study suggests that there are no significant differences in postoperative time-course changes among a u-HA/PLLA plate system, PLLA plate system, and conventional titanium plate system.

Assessment of bone healing after Le Fort I osteotomy with 3-dimensional computed tomography.

PURPOSE: The purpose of this study was to examine bone healing after Le Fort I osteotomy in Class III patients. PATIENTS AND METHODS: The study group consisted of 18 Japanese patients with mandibular prognathism with and without asymmetry, maxillary retrognathism or open bite. A total of 36 sides were examined. Le Fort I osteotomy was performed without a pterygoid osteotome, with an ultrasonic curette used to remove interference at the pterygomaxillary region. Titanium plates (Universal Mid-face fixation module, Stryker, Freiburg, German) were used for four patients, absorbable plates (poly-L-lactic acid (PLLA): NEOFIX(®), Gunze, kyoto, Japan) were used for four patients and other absorbable plates (uncalcined and unsintered hydroxyapatite and poly-L-lactic acid (uHA/PLLA): super FIXSORB(®)MX, Takiron Co. Ltd, Osaka, Japan) were used for 10 patients, in the same manner. Postoperative computed tomography (CT) was analyzed for all patients pre-operatively and 1 year postoperative. The anterior and lateral areas between the maxillary segments were measured with 3-dimensional (3D) CT. Bone healing at the pterygomaxillary region was also assessed. RESULTS: There were no significant differences in the area of bone defect healing among the plate types. The areas of bone defect after 1 year were significantly smaller than that immediately after surgery on the right side (p=0.0145) and left side (p=0.0010) in the frontal view and right side in the lateral view (p=0.0118). Bone healing at the pterygomaxillary junction was found in all cases without artificial pterygoid plate fracture. Fourteen of 22 sides with artificial pterygoid plate fracture by an ultrasonic curette showed bone continuity between the pterygoid plate and posterior part of maxilla. CONCLUSION: This study suggested that bony healing could occur in spaces between the segments of maxilla and pterygomaxillary regions as well as the region of the anterior and lateral walls in the maxilla, but it is not always complete within 1 year after Le Fort I osteotomy.

Use of self-setting α-tricalcium phosphate for maxillary sinus augmentation in rabbit.

PURPOSE: The purpose of this study was to histologically and immuno-histochemically evaluate tissue changes in the maxillary sinus after bone screw implantation and maxillary sinus augmentation using self-setting α-tricalcium phosphate (α-TCP; BIOPEX(®)-R) in rabbit. STUDY DESIGN: Adult male Japanese white rabbits (n=15, 12-16 weeks, 2.5-3 kg) were used. The sinus lift was made from the nasal bone of a rabbit. Bone screws (Dual top auto-screw(®)) were implanted into the nasal bone, and after BIOPEX(®)-R was implanted into the left elevated space (operated side) an atelocollagen sponge (ACS: Teruplug(®)) was implanted into the right elevated space (control side). The rabbits were sacrificed at 4, 12 and 24 weeks postoperatively, and formalin-fixed specimens were embedded in acrylic resin. The specimens were stained with hematoxylin and eosin. For immune-histochemical analysis, the specimens were treated with bone morphogenetic protein-2 (BMP-2) antibodies. Finally, these were evaluated microscopically. RESULTS: Tight bonding without fibrous tissue continued between the bone screw and BIOPEX(®)-R, and the rigidity of the bone screw in the nasal bone was retained for 24 weeks in all cases. The area ofnew bone formation increased gradually on both sides; however, there was no significant difference between both sides at 4, 12 and 24 weeks. The number of BMP-2-stained cells on the experimental side was significantly larger than that on the control side after 4 weeks (P=0.0361). CONCLUSION: This study suggested the usefulness of self-setting α-TCP (BIOPEX(®)-R) to maintain the rigidity of implanted bone screws from an early period, and the result of BMP-2 expression suggested that BIOPEX(®)-R could have bone-conductive activity in the maxillary sinus augmentation.

Stress change on the temporomandibular joint in mandibular prognathism subjects with asymmetry after orthognathic surgery.

The purpose of this study was to evaluate changes in stress on the temporomandibular joint (TMJ) in 80 Japanese subjects (21 males and 59 females, mean age 23.7 years) with mandibular prognathism, with and without asymmetry after orthognathic surgery using the rigid bodies spring model (RBSM). The asymmetric group consisted of 40 subjects whose Mx-Md midline was more than 3 degrees. The remaining 40 subjects formed the symmetric group. The geometry of the stress analysis model was based on frontal cephalograms of the subjects. Menton (Me), the centre point of occlusal force on a line connecting the bilateral buccal cusps of the second molars, and the most lateral, superior, and medial points on the condyle were plotted on a computer display and stress on the condyle was calculated with the two-dimensional RBSM program, Fortran. The degree (force partition) of the resultant force, the direction (angulation), and the displacement (X, Y) of each condyle were calculated and the horizontal displacement (u), the vertical displacement (v), and rotation displacement (theta) of the mandibular body at Me were calculated pre- and post-operatively. The data was analysed using paired and unpaired t-tests. For the vertical (v) and rotational (theta) displacement, the post-operative value was smaller than the pre-operative value (v: P < 0.001, theta: P = 0.0063) in the asymmetric group. For angulation and the X-component, the post-operative value was smaller than that pre-operatively on the deviated (angulation: P = 0.0074, X-component: P = 0.0003) and non-deviated (angulation: P = 0.0024, X-component: P = 0.001) side in the asymmetric group. However, there was no significant difference between the pre- and post-operative value for any parameter in the symmetric group. These findings suggest that surgical correction of mandibular prognathism, with and without asymmetry, could induce an improvement in stress balance on the TMJ in the frontal aspect.

An experimental study of use of absorbable plate in combination with self-setting α-tricalcium phosphate for orthognathic surgery.

OBJECTIVE: The purpose of this study was to histologically and immunohistochemically evaluate bone formation using both self-setting α-tricalcium phosphate (α-TCP; Biopex) and absorbable plate (Super Fixsorb-MX) in rabbit cranium bone. STUDY DESIGN: Twelve adult male Japanese white rabbits (12-16 wk, 2.5-3.0 kg) were used. The surgical defects were made in the nasal bone of a rabbit, and Biopex was implanted in the left side and no material in the right side. Two-hole absorbable plate and 2 screws (Super Fixsorb-MX) were fixed across the defect in each side. The rabbits were killed at 1, 4, 12, and 24 weeks after surgery, and formalin-fixed specimens were embedded in acrylic resin. The specimens were stained with hematoxylin and eosin. For immunohistochemical analysis, the specimens were treated with bone morphogenetic protein 2 (BMP-2) antibodies. Finally, these were evaluated microscopically. RESULTS: New bone formation was observed in the region of absorbable plate and nasal membrane after >4 weeks. The area of new bone with Biopex was significantly larger than that of the control side after 1, 4, and 12 weeks (P < .05). The number of BMP-2-stained cells in the experimental side was significantly larger than in the control side after 4 and 12 weeks (P < .05). CONCLUSION: This study suggests that the use of absorbable plate (Super Fixsorb-MX) in combination with Biopex could be useful and that both of Super Fixsorb-MX and Biopex could provide adequate bone regeneration.

Position of mandibular canal and ramus morphology before and after sagittal split ramus osteotomy.

PURPOSE: The purpose of this study was to evaluate changes in the mandibular canal and ramus morphology before and after a sagittal split ramus osteotomy. PATIENTS AND METHODS: The subjects were 30 patients (60 sides) with mandibular prognathism who had undergone bilateral sagittal split ramus osteotomy setback surgery. The mandibular canal position and ramus morphology were measured at the 3 horizontal planes under the mandibular foramen level (level A), 1 cm lower than level A (level B), and 2 cm lower than level A (level C) preoperatively and 1 year postoperatively by computed tomography. RESULTS: Postoperative ramus width, lateral distance, lateral marrow distance, and canal length were significantly larger than the preoperative values at the foramen, 1 cm lower, and 2 cm lower. The mandibular canal completely contacted the lateral cortex without lateral bone marrow in 6 sides (10%) in levels A and B and 4 sides (6.7%) in level C preoperatively and 6 sides (10%) in level C postoperatively. CONCLUSION: This study suggested that postoperative mandibular canal position was located more posteriorly and the postoperative lateral bone marrow became thicker compared with the preoperative state.

Assessment of ramus, condyle, masseter muscle, and occlusal force before and after sagittal split ramus osteotomy in patients with mandibular prognathism.

PURPOSE: The purpose of this study was to examine the relationship between the morphologies of the masseter muscle and the ramus and occlusal force before and after sagittal split ramus osteotomy (SSRO) in patients with mandibular prognathism. PATIENTS AND METHODS: The study group consisted of 26 patients with mandibular prognathism. All patients underwent bilateral SSRO as well as 3-dimensional computed tomography on which the masseter muscle, ramus, and condyle were measured preoperatively and at 1 year postoperation. Occlusal force and contact area were also recorded with pressure-sensitive sheets. RESULTS: In the cross-sectional area of the masseter muscle, there were no significant differences between the pre- and postoperative status. However, postoperative ramus width and area were significantly larger than preoperative values (P < .0001). Postoperative right condylar area was significantly larger than the preoperative value (P = .0120). Occlusal force and contact area 1 year after surgery were significantly larger than the preoperative values (P = .0016, P = .0190). CONCLUSION: This study suggested that the masseter muscle area did not significantly differ from preoperative status 1 year after SSRO, although occlusal force, contact area, and ramus area and width increased significantly 1 year after SSRO.

Determining the anatomy of the descending palatine artery and pterygoid plates with computed tomography in Class III patients.

PURPOSE: Understanding the anatomy of the pterygomaxillary junction region helps prevent blood loss in Le Fort I osteotomy. Here, we determined the location of the descending palatine artery and the structure of the pterygomaxillary region. PATIENTS AND METHODS: The study group consisted of 82 Japanese patients with mandibular prognathism and asymmetry, with and without maxillary retrognathism or asymmetry. A total of 164 sides were measured and divided into right versus left, men versus women, and bimaxillary osteotomy (B) versus mandibular osteotomy (S). Lateral and frontal cephalograms and computed tomography (CT) were analysed for all patients. The relationship between the cephalometric measurements and the measurements of the descending palatine artery and pterygoid plate (PP) were assessed. RESULTS: There were no significant correlations between measurements of cephalograms and those of the descending palatine artery and PPs. There were significant differences between right and left in lateral plate length (p=0.0014) and thickness of PP (p=0.0047). There were significant differences between men and women in right width of PP (p=0.0034), right thickness of PP (p=0.0063), left posterior length (p=0.0196), and left thickness of PP (p=0.0279). The B group had a shorter anterior length than the S group (right: p<0.0001, left: p=0.0027). CONCLUSION: These results suggest that the location of the descending palatine artery and the morphology of the PPs were not significantly associated with any cephalometric measurements. CT examination is necessary to recognize the anatomy of pterygomaxillary region and the exact positions of descending palatine artery before Le Fort I osteotomy.

Evaluation of bone formation after sagittal split ramus osteotomy with bent plate fixation using computed tomography.

PURPOSE: To evaluate bone formation between the proximal and distal segments after a sagittal split ramus osteotomy (SSRO) with bent plate fixation. PATIENTS AND METHODS: The subjects were 23 patients (46 sides) who underwent bilateral SSRO setback surgery. They were divided into titanium and absorbable plate groups. A 3 to 7-mm gap was made between the proximal and distal segments and a bent plate was fixed with 4 screws in each side of the mandible. The square of ramus (RmS), the anteroposterior length (RmA-RmP), and the mediolateral width (RmM-RmL) of the ramus at the horizontal plane under the mandibular foramen were assessed preoperatively, immediately after surgery, and 1 year postoperatively by computed tomography (CT). RESULTS: There were no significant differences between the titanium and absorbable plate groups over time. RmS after 1 year was larger than preoperatively in both groups (P < .0001). RmA-RmP significantly increased immediately after surgery and significantly decreased after 1 year in both groups (P < .0001). RmA-RmP after 1 year was significantly larger than the preoperative value in both groups (P < .0001). RmM-RmL showed a similar tendency to the anteroposterior length, but was not significant. CONCLUSIONS: The gap between the proximal and distal segments can fill with new bone after SSRO with both titanium and absorbable plates, even with few bony contacts between segments.

Assessment of pterygomaxillary separation in Le Fort I Osteotomy in class III patients.

PURPOSE: To examine the separation of the pterygomaxillary region at the posterior nasal spine level after Le Fort I osteotomy in Class III patients. PATIENTS AND METHODS: The study group consisted of 37 Japanese patients with mandibular prognathism and asymmetry, with maxillary retrognathism or asymmetry. A total of 74 sides were examined. Le Fort I osteotomy was performed without a pterygoid osteotome, with an ultrasonic curette used to remove interference at the pterygomaxillary region. Postoperative computed tomography (CT) was analyzed for all patients. The separation of the pterygomaxillary region and the location of the descending palatine artery were assessed. RESULTS: Although acceptable separation between the maxilla and pterygoid plates was achieved in all patients, an exact separation of the pterygomaxillary junction at the posterior nasal spine level was found in only 18 of 74 sides (24%). In 29 of 74 sides (39.2%), the separation occurred anterior to the descending palatine artery. In 29 of 74 sides (39.2%), complete separation between the maxilla and lateral and/or medial pterygoid plate was not achieved, but lower level separation of the maxilla and pterygoid plate was always complete. The maxillary segments could be moved to the postoperative ideal position in all cases. CONCLUSION: Le Fort I osteotomy without an osteotome does not always induce an exact separation at the pterygomaxillary junction at the posterior nasal spine level, but the ultrasonic bone curette can remove the interference between maxillary segment and pterygoid plates more safely.

Statin-induced bone morphogenetic protein (BMP) 2 expression during bone regeneration: an immunohistochemical study.

OBJECTIVES: The purpose of this study was to investigate bone morphogenetic protein (BMP) 2 expression after implantation of a statin and recombinant human BMP-2 (rhBMP-2) and to compare the bone regeneration capability of these substances in the rabbit nasal bone using immunohistologic methods. STUDY DESIGN: Twelve adult male Japanese white rabbits (n = 12; age 12-16 weeks, weight 2.5-3.0 kg) were divided into 3 experimental groups and 1 control group. A total of 48 bone defects, 4 per rabbit, were created in the nasal bone while preserving the nasal membrane. In the experimental groups, 1 group was implanted with 10 mg of a statin dissolved in 0.2 mL water with an atelocollagen sponge (ACS); the second group was implanted with 5 microg rhBMP-2 with an ACS; and in the third group only the ACS was implanted. No material was implanted in the control group. Animals were killed at 1, 2, and 4 weeks after surgery. The parts that had been operated on were removed and prepared for histologic assessment. The expression of BMP-2 was evaluated using immunohistochemistry, and double-immunostaining for BMP-2 and Ki-67 was observed by fluorescent microscopy. RESULTS: No significant differences were observed between the statin/ACS group and rhBMP-2/ACS group at 1, 2, and 4 weeks after surgery. The number of cells which stained positively for BMP-2 increased significantly in both of the implanted groups compared with the control group (P < .0001). The positive fluorescent double-immunostaining for BMP-2 and Ki-67 was similar in both implanted groups. CONCLUSION: This study suggests that statin/ACS implants show BMP-2 expression and osteoinductive activity that is similar to those of rhBMP-2/ACS implants.

Changes in the duration of the chewing cycle in patients with skeletal class III with and without asymmetry before and after orthognathic surgery.

PURPOSE: The purpose of this study was to examine the changes in the chewing rhythm before and after mandibular ramus osteotomy in patients with prognathism with and without asymmetry. PATIENTS AND METHODS: We divided 12 men and 22 women with mandibular prognathism into groups on the basis of symmetry and osteotomy procedure. The duration of the chewing cycle was recorded preoperatively and postoperatively. The duration of the chewing cycle and coefficient of variation were compared between groups, and the differences were analyzed statistically. RESULTS: No significant differences in each of 3 phases of the chewing cycle and total duration were found between groups on the basis of symmetry or osteotomy procedure. However, there were significant differences between the preoperative and postoperative coefficients of variation for the undeviated side in the asymmetry group (P = .0037) and in the group undergoing sagittal split ramus osteotomy (P = .0166). CONCLUSION: This study suggests that surgical orthodontic treatment does not significantly change the duration of the chewing cycle.

Horizontal changes in the condylar head after sagittal split ramus osteotomy with bent plate fixation.

OBJECTIVE: The purpose of this study was to evaluate the horizontal changes in the condylar head with bent plate fixation after sagittal split ramus osteotomy (SSRO) with and without a Le Fort I osteotomy. STUDY DESIGN: Of 47 Japanese patients with mandibular prognathism, 24 underwent SSRO and 23 underwent SSRO in combination with a Le Fort I osteotomy. A 3-5-mm gap was made between the proximal and distal segments, and a bent plate was fixed with 4 screws in each side of the mandible. The angle of the condylar long axis, as well as the anteroposterior and mediolateral displacement of the condylar head were assessed preoperatively and postoperatively by computerized tomography (CT). RESULTS: There was no significant difference in reduction in mandibular length between SSRO alone and SSRO with Le Fort I on the axial view of a 3-dimensional CT. There were no significant differences between pre- and postoperative horizontal changes in the condylar long axis or in the anteroposterior and mediolateral displacement of the condylar head, although the length of the proximal segment in SSRO with Le Fort I osteotomy was significantly shorter than in SSRO alone (P < .05). CONCLUSION: These results suggest that the use of a bent plate for SSRO does not change preoperative angle or position significantly in setback surgery, regardless of the addition of Le Fort I osteotomy.

The evaluation of surgical factors related to recovery period of upper lip hypoaesthesia after Le Fort I osteotomy.

PURPOSE: It is unclear whether surgical factors can affect the upper lip sensitivity. The aim of this study was to assess the factors that can affect the recovery period of hypoaesthesia of the upper lip after Le Fort I osteotomy, using trigeminal somatosensory evoked potential (TSEP) objectively. PATIENTS AND METHODS: Twenty-nine patients with mandibular prognathism underwent Le Fort I osteotomy with and without artificial pterygoid plate fracture. Trigeminal nerve hypoaesthesia at the region of the upper lip was assessed bilaterally by the TSEP method. The distance between the infraorbital foramen and the osteotomy line (IO) or the nearest plate/screw position (IP) was measured on three-dimensional computed tomography (CT). The relationship between the recovery period in upper lip hypoaesthesia and surgical factors (these distances, movement amount, pterygoid plate fracture) were analysed statistically. RESULTS: The recovery period in upper lip hypoaesthesia did not significantly correlate with IO, IP and movement amount. There was no significant difference between pterygoid plate fracture group and non-fracture group. CONCLUSION: Temporary hypoaesthesia of upper lip after Le Fort I osteotomy could not be avoided, however, osteotomy line, plate/screw position and pterygoid plate fracture in Le Fort I osteotomy did not affect the recovery period of upper lip hypoaesthesia with TSEP.

Skeletal stability after mandibular setback surgery: bicortical fixation using a 2.0-mm locking plate system versus monocortical fixation using a nonlocking plate system.

PURPOSE: This study was conducted to compare the time-course changes in condylar long-axis and skeletal stability after sagittal split ramus osteotomy (SSRO) with bicortical plate fixation versus monocortical plate fixation. PATIENTS AND METHODS: Of a group of 40 Japanese patients diagnosed with mandibular prognathism, 20 underwent SSRO with bicortical plate fixation using a locking plate system and the other 20 underwent SSRO with monocortical plate fixation using a conventional plate system. The time-course changes in condylar long-axis and skeletal stability were assessed through axial, frontal, and lateral cephalograms. RESULTS: Significant differences were found between the 2 groups in changes of the left condylar angle between the initial and 1-month measurements (P = .0454) and in ANB between the 1- and 3-month measurements (P = .0206); however, no significant differences were found between the 2 groups in the other measurements in each time interval. CONCLUSIONS: Our findings suggest no significant differences in postoperative time-course changes between bicortical plate fixation using a locking plate system and monocortical plate fixation using a conventional plate system.

Association of oral yeast carriage with specific host factors and altered mouth sensation.

OBJECTIVES: The aim of this study was to determine if there was a significant association between the presence of altered mouth and taste sensations with oral carriage of yeasts and to assess the factors that influence the yeast carriage. STUDY DESIGN: The oral and dental status including unstimulated (USFR) and stimulated (SSFR) whole salivary flow rates of a total of 509 subjects was recorded. Saliva specimens were collected for microbiologic examination. Multiple logistic regression analysis was performed to identify any factors that were significantly associated with the prevalence of oral yeasts. RESULTS: Old age, clinical signs of oral dryness, denture wearing, and a reduction in USFR increased the prevalence of yeasts, whereas patient gender, levels of dentition, the sensation of dry or burning mouth, taste disorders, and SSFR were not associated with increased prevalence of oral yeasts. CONCLUSIONS: An increased prevalence of oral yeasts was not found to relate to changes in mouth sensation alone. Other factors, most notably patient age, the wearing of dentures, clinical signs of oral dryness, and salivary flow rate under rest conditions, were, however, found to be closely associated with oral yeast carriage.

A comparative CT evaluation of pharyngeal airway changes in class III patients receiving bimaxillary surgery or mandibular setback surgery.

OBJECTIVE: The purpose of this study was to compare the morphologic changes of the upper airway space in Class III patients who underwent mandibular setback or bimaxillary surgery (maxillary advancement and mandibular setback) by computed tomography at 2 levels: soft palate and base of tongue. METHODS: The sample consisted of 47 subjects in 2 groups who had been diagnosed as having Class III skeletal deformities and had been treated by mandibular setback or bimaxillary surgery (maxillary advancement and mandibular setback). Anteroposterior, lateral, and cross-sectional area dimensions of the airway at the level of soft palate and base of tongue were measured pre- and postoperatively on computed tomography images. RESULTS: Anteroposterior dimensions of the airway decreased in both groups (P < .0001); however, the reduction was significantly less in cases treated with bimaxillary surgery (P < .05). In the mandibular setback surgery group, the cross-sectional area of the airway decreased significantly (P < .001). Although the cross-sectional area of the airway decreased in the bimaxillary surgery group, the reduction was not statistically significant (P > .05). CONCLUSIONS: This study suggests that bimaxillary surgery can prevent narrowing of the upper airway in the correction of Class III deformities in comparison with mandibular setback surgery used as the sole treatment. Computed tomography was valuable in determining the effects of surgical treatment on pharyngeal airway dimensions.