Survey of the association between tooth extraction and development of medication-related osteonecrosis of the jaw in patients undergoing cancer treatment with bone-modifying agents.

OBJECTIVE: This study aimed to verify whether tooth extraction before the administration of bone-modifying agents (BMA) was effective in preventing the onset of medication-related osteonecrosis of the jaw (MRONJ). MATERIALS AND METHODS: This retrospective study included patients with a history of receiving BMA for cancer treatment. The patients were classified into three groups based on the timing of tooth extraction: no tooth extraction before the onset of MRONJ, tooth extraction before the administration of BMA, and tooth extraction after the administration of BMA. The incidence of MRONJ was compared between the groups. Fisher's exact test and Bonferroni correction were used to test for differences in proportions between the three groups. RESULTS: The total number of subjects was 123. Twenty-four patients (19.5%) developed MRONJ. The incidence rates were 12.3% (10/81), 17.9% (5/28), and 64.3% (9/14) in the non-extraction group, the extraction before BMA administration group, and the extraction after BMA administration group, respectively, showing statistically significant differences between the extraction after BMA administration group and the non-extraction groups and between the extraction after BMA administration group and the extraction before BMA administration group (p < 0.001, p = 0.0049). On the other hand, there was no statistically significant difference in incidence between the non-extraction and the extraction before BMA administration group (p = 0.5274). CONCLUSIONS: Tooth extraction before the administration of BMA is effective in preventing the onset of MRONJ in patients receiving BMA for cancer treatment. Prevention of MRONJ development in patients receiving BMA for cancer treatment contributes to the maintenance of patients' quality of life.

Changes in nutritional status of patients with jaw deformities due to orthognathic surgery.

OBJECTIVE: In orthognathic surgery, it is important to carefully manage peri-operative nutrition because maxillomandibular fixation and problems such as swelling and pain after surgery may make it difficult to eat normally and may prevent adequate nutrition. This study investigated the changes in nutritional status of patients with jaw deformities due to orthognathic surgery. STUDY DESIGN: The subjects were 155 jaw deformity patients, who underwent orthognathic surgery. The nutritional status was evaluated using anthropometry immediately before and 10 days after surgery and clinical laboratory results and the controlling nutritional status (CONUT) score before surgery and immediately, 1 week and >6 months after surgery. We investigated the relationship among the nutritional status, surgical procedures, and dietary intake in patients who underwent orthognathic surgery. RESULTS: The surgical procedure time and amount of bleeding were significantly greater as the surgical procedure became more complex. All of the laboratory values and CONUT scores were significantly decreased immediately after surgery and then increased over time, recovering to the same level as before surgery except for serum albumin at >6 months after surgery. CONCLUSIONS: Nutritional management is considered as one of the key factors for the better and faster recovery after the orthognathic surgery.

The use of an ultrasonic curettage device in orthognathic surgery decreases surgery-related blood loss.

Objective: This study aimed to compare the use of a powered instrument (PI) and ultrasonic curettage device (ULCD) with intraoperative blood loss (IOBL), drain volume (DV), calculated blood loss (CBL), and hidden blood loss (HBL) in orthognathic surgery. Methods: We included 163 patients who underwent bimaxillary surgery in our department. CBL was calculated from the preoperative and postoperative hemoglobin levels using the "hemoglobin balance method." CBL is an indicator of the amount of perioperative blood loss. HBL was calculated by subtracting IOBL and DV from CBL. Results: The PI group consisted of 61 patients (17 males and 44 females, age: 24.9 ± 9.5 years), and the ULCD group consisted of 102 patients (40 males and 62 females, age: 23.1 ± 7.8 years). In the PI group, the median IOBL, DV, CBL, and HBL were 540.0 (interquartile range [IQR] 380.0-670.0), 113.0 (IQR 77.0-147.0), 1000.0 (IQR 751.4-1248.6), and 285.8 (IQR 151.0-476.4) ml, respectively. In the ULCD group, the median IOBL, DV, CBL, and HBL were 327.5 (IQR 200.0-455.0), 105.5 (IQR 75.3-136.0), 759.5 (IQR 594.9-944.2), and 294.2 (IQR 120.8-456.9) ml, respectively. IOBL and CBL were significantly reduced with ULCD use, but no significant differences were observed in DV and HBL. Conclusions: This study showed that IOBL decreased with ULCD use, resulting in a decrease in CBL. Conversely, bleeding parameters (DV and HBL), which reflect the amount of bleeding that occurs after wound closure, did not show a decrease with ULCD use.

Effects of medullary lesions on conditional pacemaker activity of neonatal rat hypoglossal motoneurons in vitro.

N-methyl-D-aspartate (NMDA) has been demonstrated to induce rhythmic activity in various neurons, including hypoglossal motoneurons (XIIms) and converts them to conditional pacemakers. Using whole-cell patch clamp recording in a slice preparation from neonatal rats, we confirmed that some XIIms act as conditional pacemakers, with TTX-insensitivity and a burst period that is voltage-dependent during NMDA application. Other XIIms in this study only fired tonically with NMDA application. Effects of medullary structures on conditional pacemaker XIIms were assessed using lesioned preparations. As a result, NMDA-induced rhythm (NIR) in the XIIm was observed with ventral lesions (excluding inspiratory neurons) and with dorsal lesions (excluding the swallowing center located in the nucleus of the solitary tract). The NIR was also observed with lateral lesions, but with a significantly decreased burst period. These data suggest that NMDA receptor activation selects a subset of XIIms and changes them to pacemakers whose properties can be altered by their excitability. The data also demonstrate that structures fundamental to the NIR are located within the area near the XII nucleus, indicating that the NIR is distinct from inspiratory and swallowing activities. The lateral medulla is considered to be a source of modulation of the excitability of XIIms.

Endoscopic-assisted resection of peripheral osteoma using piezosurgery.

Endoscopic-assisted surgery has gained widespread popularity as a minimally invasive procedure, particularly in the field of maxillofacial surgery. Because the surgical field around the mandibular angle is extremely narrow, the surrounding tissues may get caught in sharp rotary cutting instruments. In piezosurgery, bone tissues are selectively cut. This technique has various applications because minimal damage is caused by the rotary cutting instruments when they briefly come in contact with soft tissues. We report the case of a 33-year-old man who underwent resection of an osteoma in the region of the mandibular angle region via an intraoral approach. During surgery, the complete surgical field was within the view of the endoscope, thereby enabling the surgeon to easily resection the osteoma with the piezosurgery device. Considering that piezosurgery limits the extent of surgical invasion, this is an excellent low-risk technique that can be used in the field of maxillofacial surgery.