Calcium signaling in response to fluid flow by chondrocytes in 3D alginate culture

Quantifying the effects of mechanical loading on the metabolic response of chondrocytes is difficult due to complicated structure of cartilage ECM and the coupled nature of the mechanical stimuli presented to the cells. In this study we describe the effects of fluid flow, particularly hydrostatic pressure and wall shear stress, on the Ca(2+) signaling response of bovine articular chondrocytes in 3D culture. Using well-established alginate hydrogel system to maintain spherical chondrocyte morphology, we altered solid volume fraction to change scaffold mechanics. Fluid velocities in the bulk of the scaffolds were directly measured via an optical technique and scaffold permeability and aggregate modulus was characterized to quantify the mechanical stimuli presented to cells. Ca(2+) signaling response to direct perfusion of chondrocyte-seeded scaffolds increased monotonically with flow rate and was found more directly dependent on fluid velocity rather than shear stress or hydrostatic pressure. Chondrocytes in alginate scaffolds responded to fluid flow at velocities and shear stresses 2-3 orders of magnitude lower than seen in previous monolayer studies. Our data suggest that flow-induced Ca(2+) signaling response of chondrocytes in alginate culture may be due to mechanical signaling pathways, which is influenced by the 3D nature of cell shape.     

Role of Platelet Rich Fibrin and Platelet Rich Plasma in Wound Healing of Extracted Third Molar Sockets: A Comparative Study

Aims and objectives

This prospective study was done to evaluate and compare the utility and effectiveness of platelet rich fibrin (PRF) with that of platelet rich plasma (PRP) on soft tissue healing and bone tissue healing of extracted third molar sockets.

Materials and methods

This study included split mouths of 20 patients who underwent bilateral extraction of impacted third molars. During the same appointment, following which PRF and PRP were prepared from patients’ autologous blood and placed in right and left extracted sockets, respectively. The data for soft tissue healing were recorded at end of 1 week, using healing index of Landry et al. and the data for bone tissue healing were recorded at the end of 4 months using digitalized orthopantomogram images on Adobe Photoshop CS; which was then compared between the two sites of the same patient.

Results

The mean values of soft tissue healing collected at 1 week post-operative, for PRF group were significantly higher as compared to PRP group. And the mean values of bone density collected at the end of fourth month post-operative, for PRF group were also significantly higher as compared to PRP group. Both tests showed p value of 0.00.

Conclusion

PRF is significantly better in promoting soft tissue healing and also faster regeneration of bone after third molar extraction, in comparison with PRP. This could be attributed to simpler preparation protocols of PRF over PRP and the ability of PRF to release growth factors in a controlled way.     

Biomechanical and Finite Element Analysis of Mandibular Vertical Ramus Marginal Resection Designs

This study aims to know the post-surgical Von Mises stress of the mandible after two different vertical ramus marginal resection designs, analyze the results, compare with stress pattern of normal adult mandible without simulation and infer regarding the better of the two. Three groups of 3D finite element models of human adult mandibles were created. Group I (control)—normal mandible. Group II: Mandible with a quadrilateral vertical ramus marginal resection simulated. Group III: Mandible with an arc shaped vertical ramus marginal resection simulated. Finite element analysis (FEA) models were subjected to a point load of 475 N over right and left first molars, along with masticatory loads of masseter, medial pterygoid, anterior belly of digastric and temporalis loads in varying combinations (with and without bilateral temporalis and without right temporalis). The models were analyzed to infer the overall Von Mises stress in (a) the mandible (b) the sigmoid notch (c) postero-inferior resection corners. Results of our present study provides scientific evidence for the common practice of using arc form for marginal resection of vertical ramus of mandible whenever executed. Scientific evidence behind the concept of marginal resection of horizontal ramus is available but only scanty biomechanical evidence using finite element method (FEM) is available behind the same when performed in the vertical ramus, as magnitude and direction of loads in this region vary when compared to the horizontal ramus. The results ratify that incorporating arc shaped design pattern and removal of ipsilateral temporalis load by removal of coronoid, an area prone to stress concentration on loading, significantly decreases the post surgical Von Mises stress and hence would reduce the progressive micro-damage of the mandible after marginal resections of the vertical ramus of mandible.     

Temporal and spatial variation in plasma thyroxine (T4) concentrations in juvenile alligators collected from Lake Okeechobee and the northern Everglades,Florida, USA

We examined variation in plasma thyroxine (T4) in juvenile American alligators (Alligator mississippiensis) collected from three sites within the Kissimmee River drainage basin (FL, USA). Based on historical sediment data, Moonshine Bay served as the low contaminant exposure site, Water Conservation Area 3A served as an intermediate contaminant exposure site, and Belle Glade served as the high contaminate exposure site. In May 1999, alligators (n = 22) from Water Conservation Area 3A exhibited higher T4 concentrations than animals from both Belle Glade (n = 22; p = 0.0003) and Moonshine Bay (n = 33; p = 0.001). In May 2000, alligators (n = 29) Water Conservation Area 3A again exhibited higher T4 concentrations than those from Belle Glade (n = 49; p = 0.02) but not those from Moonshine Bay (n = 40). No sexual dimorphism was observed among mean T4 concentrations within any of the sites during either year (p > 0.05). Animals within all sites exhibited higher T4 concentrations in May 2000 when compared to May 1999. When variance was examined, animals from Water Conservation Area 3A exhibited higher variance in plasma T4 concentrations than those from either Moonshine Bay or Belle Glade. We concluded that mean plasma T4 concentrations did not match the sediment contaminant mixture data presently available to us, whereas variance seems to be a more reliable indicator of contaminant exposure.     

Efficacy of Prolotherapy in Temporomandibular Joint Disorders: An Exploratory Study

IntroductionTemporomandibular joint (TMJ) disorders can be treated by both conservative and surgical approaches. Conservative interventions with predictable benefits can be considered as first-line treatment for such disorders. Dextrose prolotherapy is one of the most promising approaches in the management of TMDs, especially in refractory cases where other conservative management has failed.AimTo study the efficacy of prolotherapy and to establish it as an effective procedure in patients with TMJ disorders, to provide long-term solution to chronic TMJ pain and dysfunctions.Patients and MethodsWe conducted a study on 25 patients suffering from various TMJ disorders who were treated with prolotherapy, the solution consisting of 1 part of 50% dextrose (0.75 ml); 2 parts of lidocaine (1.5 ml); and 1 part of warm saline (0.75 ml). The standard programme is to repeat the injections three times, at 2-week interval, which totals four injection appointments over 6 weeks with 3-month follow-up.ResultsThere was appreciable reduction in tenderness in TMJ and masticatory muscles with significant improvement in mouth opening. The effect of the treatment in improving clicking and deviation of TMJ was found to be statistically significant (P < 0.05). There were no permanent complications.ConclusionOur study concluded that prolotherapy is an effective therapeutic modality that reduces TMJ pain, improves joint stability and range of motion in a majority of patients. It can be a first-line treatment option as it is safe, economical and an easy procedure associated with minimal morbidity.     

The Versatility of Temporalis Myofascial Flap in Maxillo-Facial Reconstruction: A Clinical Study

Objectives  

This clinical study was conducted in the department of Oral & Maxillofacial Surgery, at our institute, to study the versatility of temporalis myofascial flap in maxillofacial reconstruction.     

A Prospective Study on Management of Mandibular Angle Fracture

Purpose

To evaluate the results of management of mandibular angle fracture by open reduction and internal fixation using single non compression miniplate via transbuccal, intraoral or extraoral approaches.

Patients and Methods

In this prospective study, 30 patients were randomly selected regardless of age, sex requiring open reduction and internal fixation of non comminuted angle fracture with/or without other associated fractures of the mandible. All the patients were operated under general anaesthesia following routine haematological, biochemical, general physical examination and routine radiographic examination. Patients were randomly distributed into 3 groups namely: (1) intraoral, (2) transbuccal, and (3) extraoral groups depending on the surgical approach used for open reduction and internal fixation of fracture of the angle of mandible. In the intraoral group (12 patients), angle fracture was approached through the intraoral vestibular incision similar to sagittal split incision. In the transbuccal group (8 patients), angle fracture was approached through the intraoral vestibular incision and transbuccal stab incision for screw fixation via trochar. In the extraoral group (10 patients), angle fracture was approached through the Risdon’s submandibular incision. In all the patients, fractures were reduced with upper and lower Erich’s arch bar fixation as means for IMF intraoperatively. In all the patients, fracture of the angle of the mandible was fixed with single non compression 2.5 mm, 4 holed with gap stainless steel miniplate and 6/8 mm monocortical screws. All patients were followed up for minimum of 6 months to maximum of 24 months.

Results

Complications were relatively minor such as paresthesia (on average 26.7 % first post-operative day which was gradually improved and on average after 1 month was 3.3 %), mild to moderate occlusal discrepancies (on average 36.7 %) which needed the post-operative intermaxillary fixation with elastics for 1–2 weeks, infection (20 % on average) was mild to moderate which was managed with antibiotic therapy and/or incision and drainage except in one case, plate removal was done under general anaesthesia (extraoral group) because of recurrent infection. Post-operative pain was mild to moderate (mean VAS score pre operative–6.17, post-operative 1 week–1.63) which was managed with analgesics. Mouth opening was recorded in all patients which was on average 20.98 mm preoperatively which improved to 40.57 mm after 1 month.

Conclusion

The use of a single non compression miniplate for fractures of the angle of the mandible is a simple, reliable technique with relatively rare major complications and few minor complications irrespective of the surgical approach used for the open reduction.     

Detection of Bacterial Flora in Orofacial Space Infections and Their Antibiotic Sensitivity Profile

Introduction

Most odontogenic infections arise as a sequel of pulp necrosis caused by caries, trauma, periodontitis, etc. They range from periapical abscesses to superficial and deep infections in neck. Some resolve with little consequence and some lead to severe infections of head and neck region. The purpose of this study was to identify microbial flora present in orofacial space infection of odontogenic origin and thereby provide better perspective in management of odontogenic infection.

Materials and Methods

Twenty-six patients with space infection of odontogenic origin were selected irrespective of their age and gender. Pus samples were collected and processed in the microbiology laboratory for the growth of anaerobic and aerobic bacteria and antibiotic sensitivity profile.

Results

Demographic profile of the patients showed that male patients were more commonly involved and most patients fell in to the third and fourth decade of age groups. Most common site of involvement was submandibular space. Alpha hemolytic streptococci were the frequent aerobic bacterial isolate and among anaerobes, anaerobic streptococci followed by bacteroids were the major pathogens. Clindamycin, Gentamycin, Linezolid, Imipenam were the most effective antibiotics. 20 % of the aerobes were resistant to penicillin.

Conclusion

Streptococcus species are still the commonest pathogen in orofacial infections of odontogenic origin. Administration of amoxicillin clavulanic acid combination and metronidazole followed by surgical drainage of abscess and extraction of infected teeth, yielded satisfactory resolution of infection.