Chondroprotection of articular cartilage integrity: utilizing ultrasonic scalpel and hyperosmolar irrigation solution during cutting

Objectives: Ultrasonic (US) cutting of cartilage in orthopaedic surgery has received little attention despite its potential to reduce chondrocyte death which could enhance cartilage repair. We aimed to investigate whether an ultrasonically-vibrating scalpel to cut human articular cartilage could reduce chondrocyte death, and to determine if hyper-osmolarity could provide chondroprotection during the procedure. Methods: A scalpel (no. 15) was mounted on an ultrasonic transducer to resonate at 35 kHz with 30 μm vibrational displacement. Thirty-six fresh human femoral cartilage samples were divided into four groups based on ultrasonic activation (US or non-US) and saline osmolarity (300 or 600 mOsm/L). Cell viability was assessed using a live/dead cell assay and analysed quantitatively by confocal microscopy. Histology illustrated tissue surface changes at cut site. Results: The overall chondrocyte death percentage at both the US and non-US cut sites showed comparable results (p > 0.05) in both osmolarities. However, the zone of chondrocyte death was reduced by 31 ± 5% and 36 ± 6%, respectively, when comparing US cutting at 300 mOsm/L and 600 mOsm/L to the control group (non-US cutting; 300 mOsm/L) (p < 0.05). The width of the cut was consistent at both sites, regardless of the method of cutting. Conclusion: Cutting human cartilage with US in the presence of 300 or 600 mOsm/L media was chondroprotective compared to normal (non-US) scalpel cutting in 300 mOsm/L medium. These results suggest chondroprotection can be achieved while cutting using a US scalpel and raised osmolarity, potentially improving cartilage regeneration and repair following injury

Reliability of the Panoramic Imaging Compared to Cone-beam Computed Tomography in Determining the Relationship of the Third Molar to the Mandibular Canal

Background: The incidence of injury to the inferior alveolar nerve during mandibular molar extraction increased the demand for pre-surgical planning to avoid any complications. Aim: To investigate the diagnostic accuracy of the dental panoramic image compared to cone-beam computed tomo graphy (CBCT) in predicting the inferior alveolar nerve (IAN) exposure during impacted third molar extraction. Materials and methods: This is a prospective study of consecutive patients, consulted for third molar extraction under local anesthesia. Thirty-two patients showed sign of proximity of the roots of the third molars to the mandibular canal from the dental panoramic image, were selected for CBCT. Results: With respect to the interobserver reliability, no significant difference (p < 0.05) was observed for the prediction on nerve exposure and injury from the dental panoramic image, however, showed a significant difference (p = 0.001) for the cone-beam computed tomography. The prevalence of contact between the third molar to the inferior alveolar canal (IAC) was 96.8% with a significant finding p = 0.002. There was a significant difference in the loss of cortex in predicting nerve exposure with p = 0.04. Clinically, three patients had nerve exposure and two patients had neurosensory disturbances. Conclusion: Dental panoramic image is still valuable for predicting the proximity of the third molar to the inferior alveolar canal. Nevertheless, CBCT has the best precision in localizing the close contact between the third molar and the inferior alveolar canal. Clinical significance: There was no significant finding from the CBCT for the incidence of the inferior alveolar nerve exposure and injury. However, it was seen to be accurate in predicting the IAN exposure. All these findings prove that cone-beam computed tomography contributes in the surgical plan, reduced operative time and patient morbidity

Is there an optimal initial amount of activation for midpalatal suture expansion?

Objective: Accelerated bone-borne expansion protocols on sutural separation and sutural bone formation were evaluated via histomorphometry and immunohistochemistry to determine the optimal initial activation without disruption of bone formation. Materials and methods: Sixteen New Zealand white rabbits were randomly divided into four groups. Modified Hyrax expanders were placed across the midsagittal sutures and secured with miniscrew implants with the following activations: group 1 (control), 0.5 mm expansion/day for 12 days; group 2, 1 mm instant expansion followed by 0.5 mm expansion/day for 10 days; group 3, 2.5 mm instant expansion followed by 0.5 mm expansion/day for 7 days; and group 4, 4 mm instant expansion followed by 0.5 mm expansion/day for 4 days. After 6 weeks, sutural expansion and new bone formation were evaluated histomorphometrically. Statistical analysis was performed using Kruskal–Wallis/Mann–Whitney U tests and Spearman’s rho correlation (p < 0.05). Results: The smallest median sutural separation was observed in group 1 (3.05 mm) and the greatest in group 4 (4.57 mm). The lowest and highest amount of bone formation were observed in group 4 (55.82%) and in group 3 (66.93%), respectively. Immunohistochemical analysis revealed significant differences in median levels of alkaline phosphatase and osteopontin expression between all experimental groups. The highest level of these proteins was attained in group 3, followed by groups 2, 1, and 4, respectively. Conclusions: Sutural appositional bone formation corresponded with the amount of initial expansion to a point. When initial expansion was increased to 4 mm, sutural bone remodeling was disturbed and new bone formation was decreased. The most effective sutural expansion was achieved with 2.5 mm initial activation followed by 0.5 mm expansion/day for 7 days