Time to Open Repair of Mandibular Fractures and Associated Complications.

PURPOSE: The aim of this study was to determine whether a correlation exists between the time from injury to repair of mandibular fractures and the development of postoperative complications. We also sought to assess whether a delay in treatment manifests in an increased surgical time. PATIENTS AND METHODS: We performed a retrospective cohort study and enrolled a sample (N = 64) derived from patients treated with open repair of mandibular fractures at Augusta University Medical Center by the oral and maxillofacial surgery service from July 2015 to June 2018. Time from injury to surgical repair was analyzed as a continuous variable, and the primary outcome was the presence of any of the following postoperative complications: infection, mechanical complication, cranial nerve V3 deficit, or cranial nerve VII deficit. Secondary outcome variables included the presence of substance abuse, surgical approach, and surgery time. Logistical regression was performed. RESULTS: Among 64 patients, there were 27 patients with a total of 32 complications, including infection (n = 9), mechanical complications (n = 3), cranial nerve V3 deficits (n = 13), and cranial nerve VII deficits (n = 7). The mean time to fixation was 13.26 days in patients without complications versus 17.52 days in patients with complications. The association between time to surgical repair and complication rate was not statistically significant (P = .203). No association was found between time to surgical repair and surgery time (P = .699). CONCLUSIONS: Our study did not find a significant association between the timing of repair of mandibular fractures and complications. Our study also failed to show a correlation between a delay in surgical intervention and increased technical challenges manifested by an increased surgical time.

Does Including Dexmedetomidine Improve Outcomes After Intravenous Sedation for Outpatient Dentoalveolar Surgery?

PURPOSE: Dexmedetomidine represents an intriguing adjunct to outpatient intravenous (IV) sedation owing to its decreased risk of respiratory depression. The purpose of the present study was to measure the incremental effect of incorporating dexmedetomidine (DXM) into an established IV sedation regimen compared with control IV sedation without the DXM infusion. MATERIALS AND METHODS: We designed a prospective, controlled trial in which American Society of Anesthesiologists Class 1 and 2 patients requiring both maxillary and mandibular dentoalveolar surgery would undergo 2 sedation appointments: 1 arch treated with surgery with control sedation (DXM-) using midazolam, fentanyl, and propofol as needed, and a second surgery on the opposite arch using the experimental sedation regimen (DXM+) of midazolam, fentanyl, and propofol, as needed, and a DXM infusion at 4 µg/kg/hr. The surgeon was the same for every appointment, and the patients were kept unaware regarding which sedation had included the experimental regimen. Whether the experimental sedation was used at the first or second surgery was randomized. The primary measured outcomes were efficiency in terms of anesthesia time for each sedation, the physiologic response in terms of vital signs, and the subjective patient experience. RESULTS: A total of 12 patients completed the trial. With DXM-, the patients had significantly shorter total (∼15 minutes) and adjusted anesthesia (∼10 minutes) times. With DXM+, the patients had significantly lower average systolic blood pressure (SBP), SBP low values, diastolic blood pressure (DBP) low values, average heart rate (HR), and HR low values. None of the other continuous patient outcomes differed significantly between the 2 groups. Of the 12 patients, 10 (83.3%) reported that they preferred the experimental sedation experience with DXM (95% confidence interval, 0.52 to 0.98). CONCLUSIONS: Using a DXM infusion with outpatient dentoalveolar surgery allowed for acceptable levels of sedation, greater patient satisfaction, and longer anesthesia and appointment times and often resulted in lower BP and heart rate.

Autotransplantation of Third Molars With Platelet-Rich Plasma for Immediate Replacement of Extracted Non-Restorable Teeth: A Case Series.

PURPOSE: The aim of this study was to examine the use of platelet-rich plasma (PRP) for autotransplantation of third molars as a successful technique to provide immediate tooth structure for space maintenance and masticatory function when premature loss of a permanent tooth occurs and other dental restorative options are not indicated. MATERIALS AND METHODS: This study included 10 healthy patients 10 to 17 years of age with at least 1 immature third molar (one to two thirds of root formation) used to replace extracted non-restorable teeth. Eleven third molars were transplanted and adapted to sockets of the extracted teeth with the adjunct of PRP. Transplanted teeth were stabilized to the adjacent teeth using orthodontic wires and dental composite for 1 month. Patients were followed for 1 year. Function, tooth vitality, root development, and periodontal health were recorded. RESULTS: All 10 patients had functioning asymptomatic transplanted teeth, with physiologic tooth mobility after splint removal at 1 month and after 1 year. All 10 patients had positive tooth vitality (by cold test) at 3, 6, and 12 months; all transplants showed positive root development (average growth, 2.01 mm) confirmed and measured using periapical radiographs. No patients required root canal therapy at any point in the study. Periodontal assessments were performed at the scheduled follow-up appointments with circumferential periodontal probing. Periodontal health was maintained because probing depths were shallower than 4 mm during the 1-year follow-up. CONCLUSION: Autotransplantation of immature third molars with PRP shows excellent results and should be considered a viable option for premature loss of permanent molars. PRP might have other advantages, such as root promotion and neurosensory development.

Microtubule-based nanomaterials: Exploiting nature's dynamic biopolymers.

For more than a decade now, biomolecular systems have served as an inspiration for the development of synthetic nanomaterials and systems that are capable of reproducing many of unique and emergent behaviors of living systems. One intriguing element of such systems may be found in a specialized class of proteins known as biomolecular motors that are capable of performing useful work across multiple length scales through the efficient conversion of chemical energy. Microtubule (MT) filaments may be considered within this context as their dynamic assembly and disassembly dissipate energy, and perform work within the cell. MTs are one of three cytoskeletal filaments in eukaryotic cells, and play critical roles in a range of cellular processes including mitosis and vesicular trafficking. Based on their function, physical attributes, and unique dynamics, MTs also serve as a powerful archetype of a supramolecular filament that underlies and drives multiscale emergent behaviors. In this review, we briefly summarize recent efforts to generate hybrid and composite nanomaterials using MTs as biomolecular scaffolds, as well as computational and synthetic approaches to develop synthetic one-dimensional nanostructures that display the enviable attributes of the natural filaments.

Vertical bone augmentation with simultaneous implant placement using particulate mineralized bone and mesenchymal stem cells: a preliminary study in rabbit.

This study aimed to assess vertical bone augmentation with simultaneous implant placement in rabbit tibiae using particulate mineralized bone/fibrin glue/mesenchymal stem cell. Bone marrow was aspirated from tibiae of five 10-week-old New Zealand White male rabbits. Right and left tibiae of each rabbit were prepared, and a 3-mm protruding implant from tibial bone was placed in each side. Particulate allogenic bone/fibrin glue/mesenchymal stem cell combination was placed around test implants and particulate bone graft/fibrin glue around controls. Two months postoperatively, the animals were euthanized, and sections were prepared for histological analysis. The mean amount of vertical bone length was higher in the experimental group than the control group (2.09 mm vs 1.03 mm; P < .05). New supracrestal trabecular bone formation was also significantly higher in the test group (28.5 ± 4.5% vs 4.3 ± 1.8%; P < .05). Mesenchymal stem cell/particulate allograft/fibrin glue appears to be a promising combination for vertical bone augmentation around simultaneously inserted implants in rabbit tibia.

Reducing acid in dilute acid pretreatment and the impact on enzymatic saccharification.

Dilute acid pretreatment is a leading pretreatment technology for biomass to ethanol conversion due to the comparatively low chemical cost and effective hemicellulose solubilization. The conventional dilute acid pretreatment processes use relatively large quantities of sulfuric acid and require alkali for pH adjustment afterwards. Significant amounts of sulfate salts are generated as by-products, which have to be properly treated before disposal. Wastewater treatment is an expensive, yet indispensable part of commercial level biomass-to-ethanol plants. Therefore, reducing acid use to the lowest level possible would be of great interest to the emerging biomass-to-ethanol industry. In this study, a dilute acid pretreatment process was developed for the pretreatment of corn stover. The pretreatment was conducted at lower acid levels than the conventional process reported in the literature while using longer residence times. The study indicates that a 50% reduction in acid consumption can be achieved without compromising pretreatment efficiency when the pretreatment time was extended from 1-5 min to 15-20 min. To avoid undesirable sugar degradation and inhibitor generation, temperatures should be controlled below 170°C. When the sulfuric acid-to-lignocellulosic biomass ratio was kept at 0.025 g acid/g dry biomass, a cellulose-to-glucose conversion of 72.7% can be achieved at an enzyme loading of 0.016 g/g corn stover. It was also found that acid loading based on total solids (g acid/g dry biomass) governs the pretreatment efficiency rather than the acid concentration (g acid/g pretreatment liquid). While the acid loading on lignocellulosic biomass may be achieved through various combinations of solids loading and acid concentration in the pretreatment step, this work shows that it is unlikely to reduce acid use without undermining pretreatment efficiency simply by increasing the solid content in pretreatment reactors, therefore acid loading on biomass is indicated to be the key factor in effective dilute acid pretreatment.

Retrospective study of tracheostomy indications and perioperative complications on oral and maxillofacial surgery service.

PURPOSE: Tracheostomy is an extremely common procedure performed by a variety of surgical specialties. The purpose of the present study was to review the intraoperative and perioperative management and complications, present our surgical technique, and discuss the role of our service in providing this care within a large community hospital setting. PATIENTS AND METHODS: The 112 patients in our retrospective study were divided into 3 subsets: those referred by medical specialties, tumor/reconstructive surgery patients, and trauma victims. Cases of percutaneous dilational and intensive care unit bedside tracheostomy were excluded. Intraoperative and immediately postoperative complications were included. Bleeding complications were defined as those necessitating a return to the operating room. The patients were followed up for a 24-hour period postoperatively. RESULTS: The medical referral, tumor/reconstructive, and trauma patients made up 55%, 29%, and 16% of the included patients, respectively. The overall complication rate was 2.7%. CONCLUSIONS: Conventional open tracheostomy in an operating room is associated with a low complication rate. The low incidence of perioperative bleeding can be attributed to the use of electrocautery in the division of the thyroid isthmus. This service provided an exceedingly safe and efficient surgical treatment by focusing on precise surgical protocols in an operating room setting. Intense coordination of consultation response, operating room scheduling, and communication with other services involved in these patients' care is critical to develop and maintain the privilege to provide this treatment. Our report can be used to educate the medical community regarding the role of an oral and maxillofacial surgery service in providing tracheostomy.

Can an arch bar replace a second lag screw in management of anterior mandibular fractures?

PURPOSE: To evaluate the efficacy of using a single lag screw combined with an arch bar in the management of anterior mandibular fractures and to compare this method with the traditional application of 2 lag screws. MATERIALS AND METHODS: We designed and implemented a randomized clinical trial and enrolled a sample of patients with anterior mandibular fractures. Twenty adult male patients were randomly divided into 2 equal groups according to the number of lag screws used for fracture fixation after securing the occlusion with intermaxillary fixation. In group A, the fractures were treated using 2 lag screws. In group B, the fractures were treated using a single lag screw and an arch bar on the teeth, spanning the fracture line. Clinical and radiographic evaluations were used to evaluate the efficacy of each fixation method immediately and at 2 and 4 months postoperatively. RESULTS: The clinical examination showed stable fixation with no mobility or infection in all cases. One patient in group A showed a slight occlusal discrepancy that was managed with occlusal adjustment. The pretraumatic occlusal relationship of all other patients was re-established. Postoperative radiographs showed properly reduced fracture segments with gradual bone healing. No significant difference was noted (P > .05) between the 2 groups in the development of postoperative complications. CONCLUSIONS: The use of 1 lag screw in conjunction with an arch bar across the fracture line is rigid and stable enough to manage anterior mandibular fractures without the need for supplemental intermaxillary fixation. The use of a single lag screw offers several advantages compared with the traditional use of 2 lag screws. These advantages include decreased cost, use of materials, healing time, and risk of associated morbidity.

Development of a rat model of bisphosphonate-related osteonecrosis of the jaw (BRONJ).

The purpose of this study was to develop a rat model predictive of bisphosphonate-related osteonecrosis of the jaw (BRONJ) after exodontias. Thirty female rats were randomized into 2 groups, control and experimental. The experimental group received 2 intravenous injections of zoledronate (20 µg/kg). The mesial root of the right mandibular first molar was extracted. Rats were euthanized at 0, 4, and 8 weeks. Bone mineral density (BMD), collagen breakdown (pyridinium [PYD]), vascular regeneration (VEGF), and histology were examined. A trend toward higher PYD values was suggested in control vs experimental groups after wounding. Serum VEGF increased significantly after wounding for both control and experimental groups. After 8 weeks, VEGF continued to rise for the experimental group only. In the extraction socket area, BMD was significantly lower after wounding in control vs. zoledronate-treated rats. Histology sections from experimental groups showed bacteria and bone necrosis. Consistent findings of BRONJ features similar to those in humans were observed after zoledronate treatment.

Overlap Concentration of Sodium Polystyrene Sulfonate in Solution.

The overlap concentration c* of sodium polystyrene sulfonate in water is calculated using multichain atomistic and coarse grained (CG) simulations for a range of chain lengths. Fully atomistic molecular dynamics simulations are carried out for N = 32-192 monomers. The CG model was parameterized to match the end-to-end distance from the atomistic simulations at small N and allows us to simulate a much larger N. Treating the hydrophobic backbone by inclusion of attraction between monomers is an essential addition to the CG model. The simulation c* are in agreement with experimental data, yet at c*, the chains are not fully stretched, even for N as large as 1200. This implies that none of the experimental systems are in the scaling regime and to reach the scaling regime for NaPSS chains much longer than N = 1200 are required.

Implant bone rings. One-stage three-dimensional bone transplant technique: a case report.

A variety of techniques and materials has been used to provide the structural base of bone and soft tissue support for dental implants. Alveolar bone augmentation techniques include different surgical approaches such as guided bone regeneration, onlay grafting, interpositional grafting, distraction osteogenesis, ridge splitting, and socket preservation. In the case presented, a technique was used to augment the alveolar bone three-dimensionally with autologous "bone rings" and immediate implant placement in a 1-stage procedure following teeth extraction. Bone rings (circular osteotomies) were outlined at the symphysis area using trephine burs, and a central osteotomy for implant placement was done before its removal. The rings were then removed and sculptured to fit the extraction socket; this was followed by screwing the implant through the ring, gaining its primary stability from the prepared basal bone.

Value of pre-operative CTX serum levels in the prediction of medication-related osteonecrosis of the jaw (MRONJ): a retrospective clinical study.

OBJECTIVES: The low incidence yet severe presentation of medication-related osteonecrosis of the jaw (MRONJ) makes it necessary to develop reliable predictive and preventive strategies. This study explored the value of pre-operative carboxy-terminal collagen crosslinks (CTX) serum level in the prediction of osteonecrosis-related complications in patients on bisphosphonate therapy. PATIENTS AND METHODS: We examined patient records over 4 years (a total of 137 patients). Biometric data were extracted, in addition to type of treatment, CTX levels, drug holiday, procedure, complications, and co-morbidities. Non-parametric Wilcoxon two-sample tests were used to test the effect of initial CTX level in IV or PO and whether it was predictive of complications. Two independent proportion tests were used for testing the two different complication incident rates before or after the drug holiday. RESULTS: A total of 93 patients were included in the study, of whom 88.17% were female. A total of 11 patients were receiving IV bisphosphonates at the time of initial presentation, 82 oral bisphosphonates. Out of 64 patients who underwent invasive dental procedure (IDP) before a drug holiday, eight were on IV bisphosphonates. Three patients in this group experienced osteonecrosis-related complications (37.5%). Out of the remaining 56 patients on oral bisphosphonates, four (7.14%) developed complications, significantly lower than the IV bisphosphonate group (p = 0.0364). On the other hand, of the 34 patients placed on a drug holiday prior to IDP, only one subject developed complications related to osteonecrosis. Five subjects who had operations both before and after drug holiday did not experience any complications. No statistical difference was detected in complication rates based on initial CTX level (above versus below 150 pg/ml), gender, comorbidities, or total duration of bisphosphonate treatment (p = 0.2675). The sensitivity and specificity of CTX cutoff of 150 pg/ml in predicting osteonecrosis were 37.5% and 57.7, respectively. CONCLUSIONS: Serum levels of CTX by itself are not reliable as a predictive or preventive measure for such complications. Our data also suggested that a drug holiday of 5 months was not helpful in preventing osteonecrosis-related complications in patients on intravenous bisphosphonates. Further studies are urgently needed to develop adequate predictive and preventive strategies of MRONJ.

Advances in head and neck radiotherapy to the mandible.

Management of radiation-exposed bone in the mandible is a dilemma many oral and maxillofacial surgeons must confront and manage. Current advances in radiotherapy techniques using pin-point computerized accuracy in combination with other advances, such as morphed imaging, fractionalization protocols, minimization of scatter, and pretreatment dental examinations, have greatly decreased the late effects of radiation and osteoradionecrosis. The intent of this article is to provide a brief overview of the following topics: radiotherapy physics and radiobiology, effects of radiotherapy on normal tissues, including the pathogenesis of osteoradionecrosis, and advances in contemporary radiotherapy treatment.

A revision of the genus Lepidobrya Womersley (Collembola: Entomobryidae) based on morphology and sequence data of the genotype.

The genus Lepidobrya Womersley, previously placed in Willowsiini, is re-diagnosed based on a redescription of the type species L. mawsoni (Tillyard) and its DNA barcode. Specimens possess narrow, pointed scales on the dens, two inner teeth on unguis, a truncate unguiculus with an outer tooth, a bidentate mucro with a basal spine and ordinary tergal S-chaetae 2, 2|1, 2, 2, ?, 3, so belongs to the Entomobryinae. Its systematic position and relationships to other scaled Entomobryinae genera are discussed and comments are made on the distribution of the genus as well as on ecology.

Herpes Zoster Involving the Second Division of the Trigeminal Nerve: Case Report and Literature Review.

Herpes zoster along the maxillary division of the trigeminal nerve is a rare condition that is caused by reactivation of the varicella zoster virus that resides within the trigeminal ganglion after the primary infection of chickenpox. The disease may be manifested as a toothache during its prodromal stage. The active stage of the disease is characterized by the appearance of a vesicular rash. Postherpetic neuralgia is a common complication of herpes zoster after resolution of the facial and intraoral symptoms. There is increasing evidence for herpes zoster patients to develop stroke later in life. The present case reports the development of herpes zoster maxillaris in a 71-year-old man whose maxillary right canine was diagnosed as pulpal necrosis and symptomatic apical periodontitis and was subsequently treated endodontically by cleaning and shaping and filling the canal space with gutta-percha and an epoxy resin-based sealer. The patient presented 3 days later with midfacial ulceration, desquamation, and crusting as well as intraoral ulceration along the course of the V2 dermatome. After successful treatment with antiviral medication, postherpetic neuralgia developed within the next 2 months. Complete resolution of the neuralgia occurred at the 4-month recall with negligible facial scarring. Herpes zoster may mimic odontogenic pain during the prodromal stage of the disease. Reactivation of the virus has also been implicated in the pathogenesis of pulpal pathoses. These paradoxical facets are of interest to the endodontist and should be considered in the differential diagnosis of the disease.

Should PGY-1 Be Mandatory in Dental Education? Two Viewpoints: Viewpoint 1: PGY-1 Provides Benefits That Support Making It Mandatory and Viewpoint 2: PGY-1 Should Be Available for Dental Graduates But Not Mandatory.

This Point/Counterpoint considers whether a general dentistry postgraduate year one (PGY-1) residency should be required for all new graduates who do not pursue specialty training. Currently, New York and Delaware require PGY-1 for dental licensure, while other states offer it as an alternative to a clinical examination for obtaining licensure. Viewpoint 1 supports the position that PGY-1 should be mandatory by presenting evidence that PGY-1 residencies fulfill new graduates' need for additional clinical training, enhance their professionalism and practice management skills, and improve access to care. The authors also discuss two barriers-the limited number of postdoctoral positions and the high cost-and suggest ways to overcome them. In contrast, Viewpoint 2 opposes mandatory PGY-1 training. While these authors consider the same core concepts as Viewpoint 1 (education and access to care), they present alternative methods for addressing perceived educational shortcomings in predoctoral curricula. They also examine the competing needs of underserved populations and residents and the resulting impact on access to care, and they discuss the potential conflict of interest associated with asking PGY-1 program directors to assess their residents' competence for licensure.

Single chain structure of a poly(N-isopropylacrylamide) surfactant in water.

We present atomistic simulations of a single PNIPAM-alkyl copolymer surfactant in aqueous solution at temperatures below and above the LCST of PNIPAM. We compare properties of the surfactant with pure PNIPAM oligomers of similar lengths, such as the radius of gyration and solvent accessible surface area, to determine the differences in their structures and transition behavior. We also explore changes in polymer-polymer and polymer-water interactions, including hydrogen bond formation. The expected behavior is observed in the pure PNIPAM oligomers, where the backbone folds onto itself above the LCST in order to shield the hydrophobic groups from water. The surfactant, on the other hand, does not show much conformational change as a function of temperature, but instead folds to bring the hydrophobic alkyl tail and PNIPAM headgroup together at all temperatures. The atomic detail available from these simulations offers important insight into understanding how the transition behavior is changed in PNIPAM-based systems.

Assessment of airway microbiota and inflammation in cystic fibrosis using multiple sampling methods.

RATIONALE: Oropharyngeal (OP) swabs and induced sputum (IS) are used for airway bacteria surveillance in nonexpectorating children with cystic fibrosis (CF). Molecular analyses of these airway samples detect complex microbial communities. However, the optimal noninvasive sampling approach for microbiota analyses and the clinical relevance of microbiota, particularly its relationship to airway inflammation, is not well characterized. OBJECTIVES: The goals of this study were to compare molecular analyses of concurrently collected saliva, OP swabs, IS, and expectorated sputum (ES) from children with CF and to determine the association between microbiota, lung function, and airway inflammation. METHODS: Saliva, OP swabs, IS, and ES were collected from 16 children with CF. Spirometry was performed. MEASUREMENTS AND MAIN RESULTS: Respiratory and saliva samples (n = 61) were sequenced for bacterial microbial communities, and total and CF-specific bacterial quantitative PCR assays were performed. Airway samples underwent conventional culture for CF-specific pathogens. Neutrophil elastase, IL-1ß, IL-1ra, IL-6, Il-8, TNF-α, and vascular endothelial growth factor were measured in ES and IS. Sequencing results from individual subjects were similar across samples, with greater between-subject than within-subject variation. However, Pseudomonas and Staphylococcus were detected in higher relative abundance from lower airways (ES and IS) compared with paired upper airway samples (OP and saliva). Pseudomonas, Staphylococcus, and Enterobacteriaceae correlated with increased airway inflammation. Divergence between microbiota in upper airway compared with lower airway samples, indicating greater differences between communities, was associated with increased sputum neutrophil elastase. CONCLUSIONS: Bacteria detected in IS samples resemble ES samples, whereas OP samples may underrepresent bacteria associated with airway inflammation. Divergence of lower airway communities from upper airway was associated with airway inflammation and may portend disease progression.