Can the Mechanism of Injury Impact the Location of a Mandibular Fracture? A Systematic Review.

Purpose: Mandible fractures are the second most common fractures of the facial skeleton because of the prominent position of the lower jaw. The purpose of this study was to calculate the prevalence of mandibular fractures based on their causes and locations. Materials and Method: A systematic search of 3 electronic databases from January 2010 and January 2020 was conducted following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. There were 359 articles identified for screening against selection criteria. The search identified 39 articles to be included in our analysis. Results: A total of 20,135 patients with 31,468 mandible fractures in this review. There was a 76% male predominance. The third decade was the most common age group (21-30). Motor vehicle accidents (39.89%) were the leading cause of mandible fractures, followed by falls (27.72%) and violence (25.35%). Condylar fractures are the most common cause of MVA and fall (33.11%, 50% respectively). Mandible body fractures are the second most common type of MVA injury (17.06%). When it came to violence, the angle of the mandible was the most common site (31.73%). Conclusions: The prevalence of mandible fractures was higher in male patients in the current study, particularly in the second and third decades of life. Road traffic accidents were the most common cause, and the condylar process of the mandible was the most frequently affected region. Demographic data such as age, gender, and mechanism of injury can help surgeons predict and identify specific areas of mandibular fracture.

Chondroprotective Effects of Periodontal Ligament-Derived Stem Cells Conditioned Medium on Articular Cartilage After Impact Injury.

Paracrine factors secreted in the conditioned media (CMs) of periodontal ligament-derived stem cells (PDLSCs) have been shown to downregulate inflammatory effects of interleukin (IL)-1ß on chondrocytes wherein milk fat globule-epidermal growth factor 8 (MFG-E8) is one of the PDLSCs' highly secretory proteins. Therefore, the objective of this study was to investigate the ability of PDLSC CMs and MFG-E8 to reduce the inflammatory effects of impact injury on porcine talar articular cartilage (AC) and IL-1ß on chondrocytes, respectively. Stem cells were isolated from human periodontal ligaments. The MFG-E8 content in CM collected at 5% and 20% oxygen was measured by ELISA assay and compared across subcultures and donors. AC samples were divided into three groups: control, impact, and impact+CM. Chondrocytes were isolated from pig knees and were divided into three groups: control, IL-1ß, and IL-1ß+MFG-E8. Gene expression data were analyzed by reverse transcription-polymerase chain reaction. It was found that impact load and IL-1ß treatment upregulated IL-1ß, TNF-α, ADAMTS-4, and ADAMTS-5 gene expression in AC and chondrocytes, respectively. PDLSCs-CM prevented the upregulation of all four genes due to impact, whereas MFG-E8 prevented upregulation of IL-1ß, ADAMTS-4, and ADAMTS-5 in chondrocytes, but it did not prevent TNF-α upregulation. There were no significant differences in MFG-E8 content in CM among oxygen levels, passage numbers, or donors. The findings suggested that MFG-E8 is an effective anti-inflammatory agent contributing to the chondroprotective effects of PDLSCs-CM on acutely injured AC. Thus, introducing PDLSCs-CM to sites of acute traumatic AC injury could prevent the development of post-traumatic osteoarthritis.

Anti-Inflammatory Effects of Conditioned Medium of Periodontal Ligament-Derived Stem Cells on Chondrocytes, Synoviocytes, and Meniscus Cells.

Osteoarthritis (OA) is the most common type of arthritis, afflicting millions of people in the world. Elevation of inflammatory mediators and enzymatic matrix destruction is often associated with OA. Therefore, the objective of this study was to investigate the effects of conditioned medium from periodontal ligament-derived stem cells (PDLSCs) on inflammatory and catabolic gene expressions of chondrocytes, synoviocytes, and meniscus cells under in vitro inflammatory condition. Stem cells were isolated from human periodontal ligaments. Conditioned medium was collected and concentrated 20 × . Chondrocytes, synoviocytes, and meniscus cells were isolated from pig knees and divided into four experimental groups: serum-free media, serum-free media+interleukin-1ß (IL-1ß) (10 ng/mL), conditioned media (CM), and CM+IL-1ß. Protein content and extracellular vesicle (EV) miRNAs of CM were analyzed by liquid chromatography-tandem mass spectrometry and RNA sequencing, respectively. It was found that the IL-1ß treatment upregulated the expression of IL-1ß, tumor necrosis factor-α (TNF-α), MMP-13, and ADAMTS-4 genes in the three cell types, whereas PDLSC-conditioned medium prevented the upregulation of gene expression by IL-1ß in all three cell types. This study also found that there was consistency in anti-inflammatory effects of PDLSC CM across donors and cell subcultures, while PDLSCs released several anti-inflammatory factors and EV miRNAs at high levels. OA has been suggested as an inflammatory disease in which all intrasynovial tissues are involved. PDLSC-conditioned medium is a cocktail of trophic factors and EV miRNAs that could mediate different inflammatory processes in various tissues in the joint. Introducing PDLSC-conditioned medium to osteoarthritic joints could be a potential treatment to prevent OA progression by inhibiting inflammation.

What Is the Most Stable Fixation Technique for Mandibular Condyle Fracture?

PURPOSE: Mandibular condylar fractures are relatively common fractures, accounting for 29 to 52% of all mandibular fractures. Recently, the debate between closed versus open treatment of the condylar fracture has shifted toward more specific surgical questions concerning the number and pattern of the fixation method for the condylar region. We have attempted to resolve the controversy with the systematic review and meta-analysis. The purpose of the present study was to compare the outcomes of different methods of fixation for mandibular condylar fractures. MATERIALS AND METHODS: We conducted an electronic database search for clinical studies evaluating the stability of internal fixation of condylar fractures. The search was restricted to studies reported in the English language from January 2000 to July 2018. The review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement guidelines. RESULTS: The initial search returned 285 studies reported from January 2000 through July 2018. After reviewing the full-text reports, only 16 studies were deemed eligible for the review. The total sample size was 831 patients with mandibular subcondylar fractures. The patients were classified into 25 groups according to the fixation method, follow-up period, use of intermaxillary fixation, and the presence of associated fractures. CONCLUSIONS: The results of our systematic review and meta-analysis showed that single plate fixation has been associated with more complications with poor outcomes, including hardware failure, screw loosening, and postoperative malocclusion.

Does Accurate Positioning of the Temporomandibular Joint Titanium Condylar Prosthesis Prevent Complications?

PURPOSE: Reconstruction of the temporomandibular joint defect is challenging. The purposes of this study were to identify factors associated with the accuracy of positioning of a titanium condylar prosthesis and to measure the association between the accuracy of the condylar prosthesis position and postoperative complications. MATERIALS AND METHODS: We designed a retrospective cohort study and enrolled a sample of patients whose condyle was reconstructed with an alloplastic condylar prosthesis. The primary predictor variable was the accurate positioning of the prosthesis in the fossa in comparison with the native condyle. The primary outcome variable was the development of postoperative complications related to the inaccurate positioning of the condylar prosthesis. Other variables were included and discussed in detail in the article. In addition, the postoperative pain level was assessed with a visual analog scale score. Because of the small sample size, we elected to use a descriptive data analysis for the research. RESULTS: The final sample was composed of 40 patients, with a mean age of 38 years. A postoperative complication developed in 6 patients (15%), including cutaneous plate exposure after radiation therapy, erosion through the tympanic plate of the condylar fossa, and erosion into the temporal bone. The average displacement of the condylar prosthesis in the patients in whom complications developed was 5.04 mm in the vertical and 1.5 mm in the lateral dimension, which was less than the average of all other patients in the study. Seven patients reported higher levels of pain represented by the visual analog scale score, and this was associated with increased deviation of the condylar prosthesis position by 4.4% and 16.6% in the vertical and lateral dimensions, respectively. CONCLUSIONS: This retrospective study showed that the amount of displacement of the temporomandibular joint prosthesis did not correlate with the incidence of complications or postoperative pain.

High-Energy Traumatic Maxillofacial Injury.

High-energy blunt or penetrating impact leads to great variability in facial injury patterns. Although the mechanism, pattern, and distribution of forces vary, the resultant damage to hard and soft tissues requires dedicated planning and execution of debridement and reconstructive procedures. This article evaluates the initial management of patients sustaining high-energy facial impact injuries resulting in one or more comminuted or displaced facial fractures, with accompanying severe facial lacerations and/or soft tissue defects and avulsion injuries. Seventy-three patients met the criteria for high-energy traumatic injuries at Jackson Memorial/University of Miami Medical Center between 2003 and 2013 and are included in this article. Thirty-nine patients sustained one or more gunshot wounds to the face, and 34 patients were involved in high-speed motor vehicle collisions; all patients met our criteria for high-energy trauma. The treatment protocol for these injuries involves meticulous surgical exploration and assessment, aggressive debridement, early definitive reduction/fixation, and reconstruction as necessary.

Neural crest-derived dental stem cells--where we are and where we are going.

OBJECTIVES: There are five types of post-natal human dental stem cells that have been identified, isolated and characterized. Here, we review the information available on dental stem cells as well as their potential applications in dentistry, regenerative medicine and the development of other therapeutic approaches. DATA: Data pertinent to dental stem cells and their applications, published in peer-reviewed journals from 1982 to 2013 in English were reviewed. SOURCES: Sources were retrieved from PubMed databases as well as related references that the electronic search yielded. STUDY SELECTION: Manuscripts describing the origin, retrieval, characterization and application of dental stem cells were obtained and reviewed. CONCLUSIONS: Dental stem cell populations present properties similar to those of mesenchymal stem cells, such as the ability to self-renew and the potential for multilineage differentiation. While they have greater capacity to give rise to odontogenic cells and regenerate dental pulp and periodontal tissue, they have the capacity to differentiate into all three germ line cells, proving that a population of pluripotent stem cells exists in the dental tissues. CLINICAL SIGNIFICANCE: Dental stem cells have the capacity to differentiate into endoderm, mesoderm and ectoderm tissues. Consequently they do not only have applications in dentistry, but also neurodegenerative and ischemic diseases, diabetes research, bone repair, and other applications in the field of tissue regeneration.

Biointegration of the osteo-odonto lamina in the modified osteo-odonto keratoprosthesis: engineering of tissue to restore lost vision.

The modified osteo-odonto keratoprosthesis (MOOKP) is a biologic keratoprosthesis that is used to treat a severely scarred cornea. The procedure involves multiple stages, including the transplantation of buccal mucosa to the damaged ocular surface and the implantation of an osteo-odonto lamina with a mounted polymethylmethacrylate lens. Among the keratoprostheses currently available, the MOOKP has proven to be the most effective based on the number of patients who have undergone the procedure and the duration of documented follow-up. Upon successful biointegration of the osteo-odonto lamina, the keratoprosthesis is able to resist resorption, provide stability, and prevent bacterial invasion and epithelial ingrowth. The effectiveness of the MOOKP is dependent on the anatomic and physiologic characteristics of the dental tissues and periodontal ligament.

Management of pediatric mandible fractures.

The pediatric mandible fracture is a rare occurrence when compared with the number of mandible fractures that occur within the adult population. Although the clinician who manages facial fractures may never encounter a pediatric mandible fracture, it is a unique injury that warrants a comprehensive discussion. Because of the unique anatomy, dentition, and growth of the pediatric patient, the management of a pediatric mandible fracture requires true diligence with a variance in treatment ranging from soft diet to open reduction and internal fixation. In addition to the variability in treatment, any trauma to the face of a child requires additional management factors including child abuse issues and long-term sequelae involving skeletal growth, which may affect facial symmetry and occlusion. The following is a review of the incidence, relevant anatomy, clinical and radiographic examination, and treatment modalities for specific fracture types of the pediatric mandible based on the clinical experience at the University of Miami/Jackson Memorial Hospital Oral and Maxillofacial Surgery program. In addition, a review of the literature regarding the management of the pediatric mandible fracture was performed to offer a more comprehensive overview of this unique subset of facial fractures.

Assessment of the functionality of the pectoralis major myocutaneous flap skin paddle.

INTRODUCTION: The pectoralis major myocutaneous flap (PMMF) is commonly used for oral cavity reconstruction, yet its impact on function (intelligible speech, swallowing, mastication, tongue mobility, oral competence, and mouth opening) has rarely been studied or reported in the literature. PURPOSE: This study assessed the long-term functional outcome of oral cavity reconstruction with PMMF, placing particular emphasis in its correlation with size of the skin paddle and volume of the flap. MATERIALS AND METHODS: Twenty-five patients who underwent reconstruction of compound defects of the oral cavity that involved floor of mouth, buccal mucosa, alveolar ridge, retromolar area, lateral tongue, and continuity of mandible were assessed and followed up for up to 4 years. Assessment of function was based on predetermined clinical parameters along with consecutive measurements of skin paddle size. RESULTS: At 6 months, the size of the skin paddles averaged a 37% decrease in size, along with a marked reduction in the mass effect from the flap. Tongue mobility was considered good in all patients. Speech was considered intelligible in 84% of patients, of which 16% required some concentration to understand. Initial complaints of difficulty swallowing resolved in every patient and mouth opening in all patients returned to their preoperative state. These findings were maintained consistently throughout the follow-up period. Flap complications, consisting of partial skin paddle necrosis, occurred in 4 patients (16%), but healed after local debridement. Intraoral hair in the skin paddle was present in 5 men who did not receive postoperative radiotherapy. CONCLUSIONS: Reconstruction of the oral cavity (including defects with partial involvement of the tongue and continuity of mandible) can be predictably accomplished using PMMF. These procedures are associated mostly with minor and temporary disruption of function and quality of life and few complications.

Oral and maxillofacial surgeons' role in the first successful modified osteo-odonto-keratoprosthesis performed in the United States.

Corneal disease constitutes the second most common cause of blindness and often leads to corneal damage or scarring. Several corneal scarring is a complex and difficult condition for ophthalmologists to manage. In the most severe cases, the scarring is accompanied by excessive dryness and keratinization of the ocular surface. Certain etiologies, including Stevens-Johnson syndrome, cicatricial pemphigoid, Lyell's syndrome, and chemical trauma to the surface of the eye, are responsible for the most severe cases. Traditional allogeneic corneal transplantation is not effective because of the significant scarring and dryness of the eye. To allow light and images to be focused on the retina, a keratoprosthesis is required to position a lens on the surface of the eye. One of the oldest and most effective types of keratoprosthesis, the osteo-odonto-keratoprosthesis (OOKP), was first described and documented in 1963 by Strampelli and subsequently modified by Falcinelli et al. The modified OOKP (MOOKP) is a unique prosthesis consisting of a lens fabricated from a polymethylmethacrylate (PMMA) cylinder and cemented to an autogenous graft composed of tooth and bone, traditionally termed the osteo-odonto lamina. In this context, lamina refers to a thin rectangular plate of tooth and bone (Fig 1). The MOOKP involves 4 procedures performed in 3 surgical stages.

Management of gunshot wounds to the mandible.

The gunshot wound to the mandible is a unique traumatic injury. The resultant injury from the gunshot wound is diverse because of the variability of the projectile, motion, velocity, and tissue characteristics. When a high-velocity projectile strikes the mandible, often times the wound will consist of a severely comminuted mandible surrounded by nonvital soft tissues and the implantation of multiple foreign bodies. This represents a challenge for the treating surgeon. The anatomy and function of the mandible make it such that the care of the gunshot wound requires a combination of trauma and reconstructive surgeries. There are varying techniques advocated for the management of gunshot wound to the face. However, for the comminuted mandible fracture sustained from a gunshot wound, an approach involving the fabrication of an occlusal splint, intermaxillary fixation, aggressive debridement of hard and soft tissues, and immediate reconstruction with a titanium plate is a comprehensive approach that can restore the appropriate function and contour of the patient. At the Division of Oral and Maxillofacial Surgery, University of Miami, this approach to the comminuted mandible fracture secondary to the gunshot wound has led to the effective management of this specific subset of injury. The complication rate is comparable with the current literature and provides an advantage as a 1-stage management to restore appropriate function and cosmesis to the patient.

Use of corticocancellous allogeneic bone blocks for augmentation of alveolar bone defects.

PURPOSE: The use of autogenous block bone grafts in bone regeneration procedures for alveolar ridge augmentation can be limited by donor site morbidity and complications. The purpose of the present study was to evaluate the efficacy of allogeneic corticocancellous iliac block grafts used for ridge augmentation prior to implant placement. MATERIALS AND METHODS: Forty-one patients with severe ridge volume deficiency underwent augmentation using allogeneic corticocancellous iliac block bone grafts. After rigid fixation of the graft, the site was covered with a freeze-dried allogeneic dura mater membrane, and the wound was closed with tension-free suturing. Implants were placed 3 to 4 months after surgery. Three to 6 months after implant placement, panoramic radiographs were taken and implants were uncovered for prosthetic restoration. RESULTS: Of the 57 grafts placed, one showed 2.5 mm of resorption at the superior buccal aspect of the graft. No other clinical problems were observed. The block grafts were clinically well integrated into the recipient sites and the augmented bone remained stable throughout the implant placement procedures. Of the 84 implants placed, only one failed to integrate. CONCLUSION: These results demonstrate that the use of allogeneic corticocancellous iliac block bone grafts in conjunction with guided bone regeneration principles is a viable alternative to autogenous grafts in selected patients with alveolar ridge deficiencies.

Bisphosphonates and bisphosphonate induced osteonecrosis.

Bisphosphonate-induced osteonecrosis of the jaws is the correct term for this real drug complication that most dental practitioners face. All nitrogen-containing bisphosphonates pose a risk, which is related to the route of administration, the potency of the bisphosphonate, and the duration of use. Although intravenous bisphosphonate-induced osteonecrosis of the jaws is mostly permanent, most cases can be prevented or managed if they develop, with only a few cases requiring resection for resolution. Oral bisphosphonate-induced osteonecrosis of the jaws also can be prevented with knowledge of the risk level related to the duration of use and the C-terminal telopeptide blood test results. Most cases can be resolved with a drug holiday either spontaneously or via straightforward débridement.

Bisphosphonate-induced exposed bone (osteonecrosis/osteopetrosis) of the jaws: risk factors, recognition, prevention, and treatment.

PURPOSE: Bisphosphonates inhibit bone resorption and thus bone renewal by suppressing the recruitment and activity of osteoclasts thus shortening their life span. Recently three bisphosphonates, Pamidronate (Aredia; Novartis Pharmaceuticals, East Haven, NJ), Zoledronate (Zometa; Novartis Pharmaceuticals), and Alendronate (Fosamax; Merck Co, West Point, VA) have been linked to painful refractory bone exposures in the jaws. MATERIALS AND METHODS: One hundred-nineteen total cases of bisphosphonate-related bone exposure were reviewed. RESULTS: Thirty-two of 119 patients (26%) received Aredia, 48 (40.3%) received Zometa, 36 (30.2%) received Aredia later changed to Zometa, and 3 (2.5%) received Fosamax. The mean induction time for clinical bone exposure and symptoms was 14.3 months for those who received Aredia, 12.1 months for those who received both, 9.4 months for those who received Zometa, and 3 years for those who received Fosamax. Sixty-two (52.1%) were treated for multiple myeloma, 50 (42%) for metastatic breast cancer, 4 (3.4%) for metastatic prostate cancer and 3 (2.5%) for osteoporosis. Presenting findings in addition to exposed bone were 37 (31.1%) asymptomatic, 82 (68.9%) with pain, 28 (23.5%) mobile teeth, and 21 (17.6%) with nonhealing fistulas. Eighty-one (68.1%) bone exposures occurred in the mandible alone, 33 (27.7%) in the maxilla, and 5 (4.2%) occurred in both jaws. Medical comorbidities included the malignancy itself 97.5%, previous and/or maintenance chemotherapy 97.5%, Dexamethasone 59.7%. Dental comorbidities included the presence of periodontitis 84%, dental caries 28.6%, abscessed teeth 13.4% root canal treatments 10.9%, and the presence of mandibular tori 9.2%. The precipitating event that produced the bone exposures were spontaneous 25.2%, tooth removals 37.8%, advanced periodontitis 28.6%, periodontal surgery 11.2%, dental implants 3.4% and root canal surgery 0.8%. CONCLUSIONS: Complete prevention of this complication in not currently possible. However, pre-therapy dental care reduces this incidence, and non-surgical dental procedures can prevent new cases. For those who present with painful exposed bone, effective control to a pain free state without resolution of the exposed bone is 90.1% effective using a regimen of antibiotics along with 0.12% chlorohexidine antiseptic mouth.