Kun-Jung Hsu

Late mandibular fracture after lower third molar extraction in a patient with Stafne bone cavity: a case report.

Surgical removal of the mandibular third molar is a common surgical procedure in dental clinics. Complications may include infection, bleeding, nerve injury, trismus, and accidentally displaced lower third molar, 1 but the late fracture of mandible is very rare. 2-6 Stafne cyst was first reported by Stafne in 1942 to describe the bone cavity in the angle of the mandible. 7 However, Stafne cyst is not a true cyst, and some articles have suggested that the Stafne bony cavity be renamed. 8,9 The purpose of this report is to present an unusual case of late mandibular fracture after extraction of a lower third molar in a patient with Stafne bone cavity. To our knowledge, this is the first case report in the English-language literature of these 2 rare conditions in 1 patient.

Relationship between remaining teeth and self-rated chewing ability among population aged 45 years or older in Kaohsiung City, Taiwan

The purposes of this study were to (1) examine the relationship between the number of various types of healthy remaining natural teeth at different sites and self‐rated chewing ability and (2) evaluate the relationship between the number of functional tooth units (FTUs), comprising functional natural teeth (FNT) or fixed prostheses, and self‐rated chewing ability. A sample of 296 adults (122 men and 174 women), aged 45 years or older (average age, 56.6 ± 9.7), were recruited from seven dental clinics in Kaohsiung City. Dental information on the number and status of remaining teeth was obtained through examination by trained and calibrated dentists. Self‐assessment of chewing ability (masticatory score) was evaluated with a self‐administered questionnaire. Results showed that increased age is associated with a greater likelihood of difficulty in chewing. To avoid chewing difficulty, at least 24.7 FNT, 13.3 posterior‐FNT, 8.1 units of natural tooth‐FTUs, or 9.6 units of fixed tooth‐FTUs must remain. Age and the number of healthy remaining teeth, including natural teeth and fixed prostheses, are key factors in chewing ability. Given that aging is unavoidable, the preservation of healthy remaining teeth plays a relatively important role in the maintenance of chewing ability among middle‐aged and elderly people.

Soft-tissue profile changes after orthognathic surgery of mandibular prognathism

During surgical correction of facial deformities, accurate prediction of the resulting facial profile is important for the patient and the surgeon. The purpose of the present study was to investigate profile changes after surgical treatment of mandibular prognathism. Thirty patients (20 females and 10 males; ages 17–28 years) with mandibular prognathism underwent vertical ramus osteotomy. Preoperative and postoperative cephalograms were analyzed; landmarks were identified and compared. The mean horizontal setback of the pogonion (Pog) was 11.7 mm. The setback ratios of labrale inferius (Li)/incision inferius (Ii), labiomental sulcus (Si)/point B, and soft tissue pogonion (PogS)/pogonion (Pog) were 0.98, 0.99, and 0.95, respectively. There were no sex‐related changes in soft tissue. These findings indicate that changes in soft tissue closely correlate with the amount of mandibular setback in the horizontal direction. Such information might facilitate more accurate prediction of the outcome of orthognathic surgery.

Correlation Between Blood Loss and Patient-Related Factors in the Bilateral Parasymphyseal Osteotomy.

AbstractThe aim of this study was to determine the correlation between pre- and postsurgical loss of blood and blood components among patients undergoing treatment of facial deformities by bilateral parasymphyseal osteotomy (BPsO).The pre- and postoperative values of blood components were determined in 30 facial deformity patients who underwent orthognathic surgery by hypotensive anesthesia.Correlations among the blood loss, sex, age, operation time, and reduced values of blood components were assessed by a correlation matrix.The mean blood loss and operation time were 437.5 (±52.5) mL and 355.8 (±209.42) minutes, respectively. Two patients included in this study had required blood transfusion. The mean reduced red blood cell (×106/&mgr;L), hemoglobin (g/dL), and hematocrit (%) were −1.02, −2.98, and −9.18, respectively. There was no significant correlation between blood loss and other related factors (eg, age, operation time, and reduced blood components). All patients, however, showed significantly lower values of blood components after surgery.In conclusion, no significant factor was associated with blood loss and reduced blood components among patients undergoing BPsO. Furthermore, hypotensive anesthesia is a well-accepted method to reduce blood loss during orthognathic surgery.

Correlation between change of tongue area and skeletal stability after correction of mandibular prognathism

The purpose of this study was to investigate the correlation between postoperative stability and a change in tongue area after treatment of mandibular prognathism. Twenty‐six patients, who were treated for mandibular prognathism using intraoral vertical ramus osteotomy, were evaluated cephalometrically. A set of three standardized lateral cephalograms were obtained from each participant preoperatively (T1), immediately postoperatively (T2), and after 2 years postoperatively (T3). Student t test and Pearson correlation coefficient were used for statistical analysis. Immediately after the surgery (T12), the setback of the menton (Me) was 12.9 mm (p < 0.001) and the tongue area had significantly increased to 105.8 mm2 (p = 0.047). At a 2‐year follow‐up to examine postsurgical stability (T23), the Me exhibited a forward movement of 0.6 mm (p = 0.363) and the tongue area had significantly decreased to 124.3 mm2 (p = 0.004). Pearson correlation coefficient test revealed no statistical significance between postoperative stability and change in tongue area. The tongue area significantly increased during the T12 period and decreased during the T23 period. There is no significant correlation between postoperative skeletal relapse and a change in tongue area.

The Effect of Pterygomasseteric Sling’s Area in the Postoperative Stability after Mandibular Setback Surgery

Purpose The purpose of the present study was to investigate the correlation between the postoperative stability and area of pterygomasseteric sling (PMS). Materials and Methods Forty patients of mandibular prognathism were treated by isolated mandibular setback. Serial lateral cephalograms were collected (preoperatively [T1], immediately after surgery [T2], and more than 1 year postoperatively [T3]). The postoperative stability (T32) was divided into 3 groups (total, forward, and backward movements). The areas of PMS, immediate surgical changes (T21), postoperative stability (T32), and final surgical change (T31) were analyzed by Students t-test, Pearsons correlation coefficient, and multiple linear regression analysis. Results The amount of mean setback (T21) was 12.6 mm in total group, 13.8 mm in forward group, and 10.8 mm in backward group. In the total group, postoperative stability (T32) was 0.6 mm forward and reduction area of PMS (T31) was 291 mm2 (17.2%). The reduction area of PMS (T31) was 298.2 mm2 (18%) and 263.1 (15.3%) mm2 in the forward group (3 mm) and backward group (2.4 mm), respectively. However, reduction area of PMS (T31) showed weak correlation with postoperative stability (T32) in all groups. Conclusion Total and forward groups presented significant correlations between postoperative stability (T32) and amount of setback (T21).

Relationship between Frontal Gap and Postoperative Stability in the Treatment of Mandibular Prognathism

Objectives. To investigate the correlation between frontal gaps and skeletal stability after intraoral vertical ramus osteotomy (IVRO) for correction of mandibular prognathism. Materials and Methods. Thirty-three patients with frontal gaps after IVRO-based mandibular prognathism correction were included. Three lateral and frontal cephalometric radiographs were obtained: preoperatively (T1), immediately postoperatively (T2), and 2 years postoperatively (T3). Two linear measurements (menton [Me] and frontal gap) were compared from T1 to T3 (T21: immediate surgical changes; T32: postoperative stability; T31: 2-year surgical change). Data were analyzed using Pearsons correlation coefficient and multiple linear regression. Results. The T21 mean surgical horizontal change in the Me position was 12.4 ± 4.23 mm. Vertically, the mean downward Me movement was 0.6 ± 1.73 mm. The mean frontal gaps were 4.7 ± 2.68 mm and 4 ± 2.48 mm in the right and left gonial regions, respectively. Postoperative stability (T32) significantly correlated with the amount of setback. Frontal gaps did not have a significant effect on postoperative stability. However, multiple regression model (R 2 = 0.341, P = 0.017) showed value predictability, especially in the amount of setback. Conclusion. Frontal gaps occur after IVRO but have no significant effect on long-term postoperative skeletal stability. The primary risk factor for postoperative relapse remains the amount of mandibular setback.