Effect of Orthognathic Surgery On Pulp Blood Flow and Pulp Sensibility: A Prospective Control Trial.

INTRODUCTION: Orthognathic surgery has the potential to compromise the vitality of the teeth. This paper aims to assess changes in pulp blood flow (PBF) and pulp sensibility (PS) of the anterior dentition following orthognathic surgery and to assess the influence of the proximity of the surgical osteotomy on the PBF and/or PS. METHODS: Twenty-six patients undergoing orthognathic surgery (Le Fort I or bilateral sagittal split osteotomy [BSSO]) were compared to sixteen control patients treated by fixed appliances only using Laser Doppler flowmeter (LDF) and thermal testing (CO2 snow). Surgery patients were tested at T1 (presurgery), T2 (4-5 weeks postsurgery), T3 (3 months postsurgery), and T4 (6 months postsurgery). Control patients were tested at T1 (pretreatment), T2 (6 months posttreatment), T3 (12 months posttreatment), and T4 (18 months posttreatment). Differences between the maxilla and mandible were assessed. RESULTS: No differences in PBF or PS were recorded in the control group. In the surgery group, both jaws followed the same pattern after surgery, an initial decrease at T2 followed by a gradual recovery to pretreatment PBF levels with no significant difference between T1 versus T4 in both jaws. No difference in PBF was observed between the maxilla and mandible at any testing time interval. CONCLUSIONS AND CLINICAL IMPLICATIONS: PBF and PS of the anterior dentition was severely affected immediately postsurgery, followed by a gradual increase to full recovery. This pattern of recovery was exhibited in both jaws. A negative sensibility response or discoloration should not be seen as an indication of irreversible ischemic pulp changes. Monitoring for at least 6 months or using LDF as a confirmatory test is required before any irreversible endodontic treatment is to be considered.

Mandibular Arteriovenous Malformation (Vascular Lesion) in a 16-Year-Old Patient.

Intraosseous arteriovenous malformations in jaws are rare congenital vascular abnormalities that the dentist may encounter. A vascular lesion or disease should be suspected when there is unexplained bleeding from the oral cavity. Diagnostic imaging is a valuable tool in diagnosing and localizing vascular lesions. An understanding of some of the salient clinical and radiographic features of arteriovenous malformations in jaws aids the clinician in correctly diagnosing this condition and avoids iatrogenic injuries, such as hasty tooth extraction, which may potentially cause severe bleeding and possibly death. The dentist should acknowledge their expertise/limitation, and know when the need for referral arises.

Anatomical features of the mandibular canal and their clinical significance - review of literature.

The clinical issues related to the anatomical variation of the mandibular canal have been extensively analyzed since the 19th century. Evolving dentistry techniques and advancements in the prosthetics forced to collect detailed information about anatomical variations of the mandibular canal due to its neurovascular content. Therefore, its radiographic imaging became an essential part of the oral surgery, in order to avoid complications resulted from an accidental damage of the mandibular canal.

The potential for facial artery injury during mandibular third molar extraction. An anatomical study using contrast-enhanced computed tomography.

The purpose of this study was to evaluate the risk of injury to the facial (FA) and related arteries during mandibular third molar (MTM) extraction using contrast-enhanced computed tomography (CE-CT). CE-CT images of the MTM region were retrospectively reviewed. The area of the MTM was equally divided into three zones in the coronal images from mesial to distal, that is, zone 1, zone 2, and zone 3. The FA, submental artery (SMA), and sublingual artery (SLA) were identified. The distance from the mandible to FA, SMA, and SLA and the diameter of the FA, SMA, and SLA was measured in three zones, respectively. The thickness of the facial soft tissues and width of the mandible were measured at their maximum. The mean distance from the FA to the buccal cortical bone in zone 1, zone 2 and zone 3 was 2.24 mm, 2.39 mm and 1.67 mm, respectively. The SMA and SLA were found to be distal to the mandible. The mean diameter of the FA was 1.26 mm in males and 1.04 mm in females, respectively (p < 0.0001). The distance between the FA and buccal cortical bone of the mandible, and the patients' weight showed moderate correlation in zones 1 and 2. Based on our findings, the FA can be damaged if the surgical invasion reaches the facial soft tissues during MTM surgery. The patients' weight might be a good predictor for FA injury when CE-CT is not available.

Trifurcation of the facial artery at the inferior border of the mandible: a case report.

PURPOSE: The facial artery is known to show variations in its origin, course, termination, and branching pattern. This study aimed to present a case with trifurcation of the facial artery at the inferior border of the mandible accompanied by variable branches. METHODS: During our routine head dissection, it was observed that a 67-year-old male cadaver had a trifurcation of the facial artery at the level of the lower border of the mandible on the left. The skin was reflected, and the subcutaneous fatty tissue and subcutaneous layers were dissected to reveal the triple facial artery. RESULTS: The left facial artery arising from the external carotid artery entered the face with three branches as it crossed the lower border of the mandible. The three branches are the anterior, intermediate, and posterior branches. The posterior branch passed in front of the anterior border of the masseter muscle along with the facial vein and gave off muscular branches with a straight course, whereas the anterior thickest curved branch terminated by the inferior labial artery, and a tortuous intermediate branch initially gave off the superior labial artery and then terminated by the angular artery. CONCLUSION: Understanding these variational branches of the triple facial artery and their relationships is crucial for avoiding complications in reconstructive and reparative maxillofacial, craniofacial and plastic surgery in order to mitigate the risk of damage to the facial artery during flap surgery.

Use of Kinesiography to Assess Mandibular Function Following Segmental Resection and Microvascular Reconstruction.

Mandibular reconstruction has attained adequate morphological outcomes. However, some patients encounter difficulties in oral function and limited mandibular movements. An objective: evaluation has seldom featured actual kinetic measurements after mandibular reconstruction.Thirty patients who underwent mandibular reconstruction using bony free flap were enrolled in the study. Twenty-two patients were recruited after surgery and compared to a control group of 8 healthy subjects; 8 patients underwent both pre and postoperative evaluations. For each patient, a kinesiographic scan was obtained, recording maximum mouth opening, maximal laterality, and maximal protrusion.All postoperative kinesiographic evaluations were performed at least 6 months after surgery to ensure complete healing. In the first group of 22 patients, all measured movements were less than those of healthy controls, in particular maximum mouth opening. In the second study group (pre and postoperative evaluation), the postsurgical values did not achieve the control ones, but were no less than the preoperative values, granting adequate functional outcomes.The kinesiograph appears useful for objectively recording the functional outcomes in patients who have undergone mandibular reconstruction. The postoperative jaw movements were acceptable, ensuring a sufficient functional recovery.

Development of a Rat Model of Mandibular Irradiation Sequelae for Preclinical Studies of Bone Repair.

Repairing mandibular bone defects after radiotherapy of the upper aerodigestive tract is clinically challenging. Although bone tissue engineering has recently generated a number of innovative treatment approaches for osteoradionecrosis (ORN), these modalities must be evaluated preclinically in a relevant, reproducible, animal model. The objective of this study was to evaluate a novel rat model of mandibular irradiation sequelae, with a focus on the adverse effects of radiotherapy on bone structure, intraosseous vascularization, and bone regeneration. Rats were irradiated with a single 80 Gy dose to the jaws. Three weeks after irradiation, mandibular bone defects of different sizes (0, 1, 3, or 5 mm) were produced in each hemimandible. Five weeks after the surgical procedure, the animals were euthanized. Explanted mandibular samples were qualitatively and quantitatively assessed for bone formation, bone structure, and intraosseous vascular volume by using micro-computed tomography, scanning electron microscopy, and histology. Twenty irradiated hemimandibles and 20 nonirradiated hemimandibles were included in the study. The bone and vessel volumes were significantly lower in the irradiated group. The extent of bone remodeling was inversely related to the defect size. In the irradiated group, scanning electron microscopy revealed a large number of polycyclic gaps consistent with periosteocytic lysis (described as being pathognomonic for ORN). This feature was correlated with elevated osteoclastic activity in a histological assessment. In the irradiated areas, the critical-sized defect was 3 mm. Hence, our rat model of mandibular irradiation sequelae showed hypovascularization and osteopenia. Impact statement Repairing mandibular bone defects after radiotherapy of the upper aerodigestive tract is clinically challenging. Novel tissue engineering approaches for healing irradiated bone must first be assessed in animal models. The current rat model of mandibular irradiation sequelae is based on tooth extraction after radiotherapy. However, the mucosal sequelae of radiotherapy often prevent the retention of tissue-engineered biomaterials within the bone defect. We used a submandibular approach to create a new rat model of mandibular irradiation sequelae, which enables the stable retention of biomaterials within the bone defect and should thus facilitate the assessment of bone regeneration.

Quantitative Dynamic Contrast-Enhanced MRI Identifies Radiation-Induced Vascular Damage in Patients With Advanced Osteoradionecrosis: Results of a Prospective Study.

PURPOSE: We aim to characterize the quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) parameters associated with advanced mandibular osteoradionecrosis (ORN) compared with the contralateral normal mandible. METHODS AND MATERIALS: Patients with a diagnosis of advanced ORN after curative-intent radiation treatment of head and neck cancer were prospectively enrolled after institutional review board approval and study-specific informed consent were obtained. Quantitative maps generated with the Tofts and extended Tofts pharmacokinetic models were used for analysis. Manual segmentation of advanced ORN 3-dimensional volume was done using anatomic sequences to create ORN volumes of interest (VOIs). Subsequently, normal mandibular VOIs were segmented on the contralateral healthy mandible of similar volume and anatomic location to create control VOIs. Finally, anatomic sequences were coregistered to DCE sequences, and contours were propagated to the respective parameter maps. RESULTS: Thirty patients were included. The median time to ORN diagnosis after completion of IMRT was 38 months (range, 6-184 months), whereas median time to ORN progression to advanced grade after initial diagnosis was 5.6 months (range, 0-128 months). There were statistically significant higher Ktrans and Ve in ORN-VOIs compared with controls (0.23 vs 0.07 min-1, and 0.34 vs 0.15; P < .0001 for both). The average relative increase of Ktrans in ORN-VOIs was 3.2-fold higher than healthy mandibular control VOIs. Moreover, the corresponding rise of Ve in ORN-VOIs was 2.7-fold higher than in the controls. Using combined Ktrans and Ve parameters, 27 patients (90%) had at least a 200% increase of either of the studied parameters in the ORN-VOIs compared with their healthy mandible VOIs. CONCLUSIONS: Our results confirm that there is a quantitatively significant higher degree of leakiness in the mandibular vasculature as measured using DCE-MRI parameters of areas with advanced ORN versus healthy mandible.

Anomalous Course of Facial Artery Through the Submandibular Gland and its Redundant Loop at the Base of Mandible.

Knowledge of variant course and branching pattern of the facial artery gains importance in the surgeries of upper neck and face. The authors report a unilateral anomalous course and a redundant loop of right facial artery as seen in an adult male cadaver. The right facial artery had its origin from the external carotid artery. It pierced through the submandibular salivary gland and formed a redundant loop at the base of the mandible. Its further course and branching pattern was normal. This case could be important for radiologists, plastic surgeons and craniofacial surgeons.

New proposed classification ofretromandibular vein root variants based on cadaver dissections andreview of literature - Clinicalimplications

Typically the retro-mandibular vein contributes to formation of common facial and external jugular veins, via its anterior and posterior divisions respectively. However, cervico-facial venous variants are rather common. In two successive cadaver dissections the left side of head and neck were unviewable, but the right cervico-facial veins were visible. In both cadavers the right retro-mandibular vein was undivided. The first specimen had right external jugular vein draining into the right subclavian vein but did not have a right common facial vein. The second specimen did not have a right external jugular vein, but had a right common facial vein draining into the right internal jugular vein.The first variant was characterized as Posterior Dominant Retromandibular Vein with no Common Facial Vein. The second variant was characterized as Anterior Dominant Retromandibular Vein with no External Jugular Vein. Each was sub-classified as Typical or Atypical based on its final drainage pattern. Cervico-facial venous variants often vary from case to case and side to side. Since external jugular and common facial veins are used for clinical and surgical interventions, accurate and structured preoperative classification of variations may preclude intra-operative surprises and consequentcomplications

No disponible

Clinical anatomy of the accessory mandibular foramen: application to mandibular ramus osteotomy.

PURPOSE: An accessory foramen around the mandibular foramen is called an accessory mandibular foramen (AMF). The clinical anatomy of the AMF has not been well described. The aim of this study was to reveal the clinical anatomy of the AMF for a better understanding of its implication during ramus surgeries. METHODS: Twenty-two sides fresh-frozen cadaveric heads with a mean age of 76.2 ± 14.4 years at death underwent dissection. The neurovascular bundles passing through the AMF were observed. Additionally, a hemi-face of a latex injected embalmed cadaver was dissected medially to laterally and the neurovascular bundles of the AMF investigated. RESULTS: A unilateral foramen, bilateral foramina, and absence of foramina were found in 45.4%, 18.2%, and 36.4%, respectively. The origin of the neurovascular bundle entering the AMF was a branch of the maxillary artery in 20% and a tributary of the inferior alveolar vein in 80%. In the latex embalmed cadaver, the AMF was found to contain a branch from the maxillary artery and a tributary of the maxillary vein. CONCLUSION: Given the practical meaning of the specific AMF located in the operative field of the ramus osteotomy, we suggest these be named "foramina for ramus osteotomy."

Endosteal blood supply of the mandible: anatomical study of nutrient vessels in the condylar neck accessory foramina.

PURPOSE: In the mandible, the condylar neck vascularization is commonly described as mainly periosteal; while the endosteal contribution is still debated, with very limited anatomical studies. Previous works have shown the contribution of nutrient vessels through accessory foramina and their contribution in the blood supply of other parts of the mandible. Our aim was to study the condylar neck's blood supply from nutrient foramina. METHODS: Six latex-injected heads were dissected and two hundred mandibular condyles were observed on dry mandibles searching for accessory bone foramina. RESULTS: Latex-injected dissections showed a direct condylar medular arterial supply through foramina. On dry mandibles, these foramina were most frequently observed in the pterygoid fovea in 91% of cases. However, two other accessory foramina areas were identified on the lateral and medial sides of the mandibular condylar process, confirming the vascular contribution of transverse facial and maxillary arteries. CONCLUSIONS: The maxillary artery indeed provided both endosteal and periosteal blood supply to the condylar neck, with three different branches: an intramedullary ascending artery (arising from the inferior alveolar artery), a direct nutrient branch and some pterygoid osteomuscular branches.

Determination of baseline alveolar mucosa perfusion parameters using laser Doppler flowmetry and tissue spectrophotometry in healthy adults.

Objectives: To determine the baseline perfusion parameters of the alveolar mucosa using laser Doppler flowmetry and tissue spectrophotometry (LDF-TS) in healthy adults.Material and methods: Forty-two healthy adult subjects of either sex were tested. The perfusion of the alveolar mucosa was evaluated using a laser Doppler flowmetry and tissue spectrophotometry using O2C 'oxygen to see' device. The measurements encompassed the maxillary and mandibular mucosa at 20 different points.Results: The O2C device is a reliable method for noninvasive measurement of different perfusion parameters of the oral mucosa. The hemoglobin saturation values (So2 in %), as well as relative amount of hemoglobin in arbitrary units (AU) of the maxillary mucosa demonstrated lower values of that in the mandible. The flow value (AU) exhibited a significant difference in the posterior molar region only, while the velocity value (AU) showed a significant difference across all points except for the anterior region.Conclusion: the present study provides a set of brand-new perfusion parameters of the microcirculation of the alveolar mucosa using LDF-TS. The study suggests a variation of the perfusion parameters between the maxilla and the mandible. Differences in the anatomy of the blood supply, the thickness of the mucosa and the cortical bone, may be attributed to this variation. Further studies using different probes and a combination of ultrasonic measurements and SDF imaging will aid in giving a better overview of the perfusion in the oral mucosa.

Quantifying Vascular Changes Surrounding Bone Regeneration in a Porcine Mandibular Defect Using Computed Tomography.

Angiogenesis is a critical process essential for optimal bone healing. Several in vitro and in vivo systems have been previously used to elucidate some of the mechanisms involved in the process of angiogenesis, and at the same time, to test potential therapeutic agents and bioactive factors that play important roles in neovascularization. Computed tomography (CT) is a noninvasive imaging technique that has recently allowed investigators to obtain a diverse range of high-resolution, three-dimensional characterization of structures, such as bone formation within bony defects. Unfortunately, to date, angiogenesis evaluation relies primarily on histology, or ex vivo imaging and few studies have utilized CT to qualitatively and quantitatively study the vascular response during bone repair. In the current study a clinical CT-based technique was used to evaluate the effects of rhBMP-2 eluting graft treatment on soft tissue vascular architecture surrounding a large segmental bone defect model in the minipig mandible. The objective of this study was to demonstrate the efficacy of contrast-enhanced, clinical 64-slice CT technology in extracting quantitative metrics of vascular architecture over a 12-week period. The results of this study show that the presence of rhBMP-2 had a positive effect on vessel volume from 4 to 12 weeks, which was explained by a concurrent increase in vessel number, which was also significantly higher at 4 weeks for the rhBMP-2 treatment. More importantly, analysis of vessel architecture showed no changes throughout the duration of the study, indicating therapeutic safety. This study validates CT analysis as a relevant imaging method for quantitative and qualitative analysis of morphological characteristics of vascular tissue around a bone healing site. Also important, the study shows that CT technology can be used in large animal models and potentially be translated into clinical models for the development of improved methods to evaluate tissue healing and vascular adaptation processes over the course of therapy. This methodology has demonstrated sensitivity to tracking spatial and temporal changes in vascularization and has the potential to be applied to studying changes in other high-contrast tissues as well. Impact Statement Tissue engineering solutions depend on the surrounding tissue response to support regeneration. The inflammatory environment and surrounding vascular supply are critical to determining if therapies will survive, engraftment occurs, and native physiology is restored. This study for the first time evaluates the blood vessel network changes in surrounding soft tissue to a bone defect site in a large animal model, using clinically available computed tomography tools and model changes in vessel number, size, and architecture. While this study focuses on rhBMP2 delivery impacting surrounding vasculature, this validated method can be extended to studying the vascular network changes in other tissues as well.

Effect of local administration of simvastatin on orthodontic tooth movement in rabbits.

INTRODUCTION: Maintaining tooth anchorage during orthodontic treatment has challenged orthodontists and threatening the success of some orthodontic therapy. The objective of this study was to evaluate the effect of local administration of simvastatin on orthodontic tooth movement. METHODS: Nickel-titanium coil springs were used to induce orthodontic tooth movement in 10 white New Zealand rabbits for 21 days. A split-mouth design was implemented where one mandibular quadrant received local administration of simvastatin and the corresponding mandibular quadrant received control vehicle solution on a weekly basis. Magnitudes of tooth movement were measured on 3-dimensional models of the experimental teeth. Animals were killed at the end of the experimental period to allow histomorphometric analysis of alveolar bone modeling. RESULTS: The total magnitude of tooth movement in the quadrant receiving simvastatin was significantly less than that in the quadrant receiving control vehicle solution. Local administration of simvastatin resulted in a significant percentage of inhibition of tooth movement of 39.8 ± 22.6%. Histomorphometric analysis revealed a significant reduction in the numbers of osteoclasts and areas of active bone-resorptive lacunae hindering bone resorption processes in the quadrant receiving simvastatin. CONCLUSIONS: Local administration of simvastatin can reduce the rate and magnitude of orthodontic tooth movement. Moreover, local administration of simvastatin diminishes bone resorption processes associated with orthodontic tooth movement reducing the number of osteoclasts and the subsequent area of active bone resorption.

Free Flap Outcomes of Microvascular Reconstruction after Repeated Segmental Mandibulectomy in Head and Neck Cancer Patients.

This is the first study to investigate the impact of a second fibula flap or a soft tissue flap combined with bridging plate for a repeated segmental mandibulectomy reconstruction on flap outcomes in head and neck cancer patients. A retrospective comparative analysis (2007-2016) of 61 patients who underwent a second segmental mandibulectomy was performed. 20 patients underwent a fibula flap reconstruction whereas 41 had a soft tissue flap and plate reconstruction. No significant difference was seen in the operative time, total hospital stay, flap loss, re-exploration rates, plate exposure rate, or recipient site infection rate. On multivariate analysis, patients reconstructed with a soft tissue flap and bridging plate (odds ratio (OR) 3.997; 95% confidence interval (CI), 1.046-15.280, p = 0.043) and complications developed in previous surgery (OR 4.792; 95% CI, 1.120-20.493, p = 0.035) were shown to be independent predictors of a prolonged nasogastric tube dependence. The utilization of a soft tissue flap with plate is associated with comparative results of acute complication rate within 1 week, recipient site infection rate, and plate exposure rate to free fibula flaps alone. Free fibula flaps may result in a decreased risk for prolonged tube dependence compared to free soft tissue flap reconstructions.

Cephalometric studies of the mandible, its masticatory muscles and vasculature of growing Göttingen Minipigs-A comparative anatomical study to refine experimental mandibular surgery.

Over many decades, the Göttingen Minipig has been used as a large animal model in experimental surgical research of the mandible. Recently several authors have raised concerns over the use of the Göttingen Minipig in this research area, observing problems with post-operative wound healing and loosening implants. To reduce these complications during and after surgery and to improve animal welfare in mandibular surgery research, the present study elucidated how comparable the mandible of minipigs is to that of humans and whether these complications could be caused by specific anatomical characteristics of the minipigs' mandible, its masticatory muscles and associated vasculature. Twenty-two mandibular cephalometric parameters were measured on CT scans of Göttingen Minipigs aged between 12 and 21 months. Ultimately, we compared this data with human data reported in the scientific literature. In addition, image segmentation was used to determine the masticatory muscle morphology and the configuration of the mandibular blood vessels. Compared to data of humans, significant differences in the mandibular anatomy of minipigs were found. Of the 22 parameters measured only four were found to be highly comparable, whilst the others were not. The 3D examinations of the minipigs vasculature showed a very prominent deep facial vein directly medial to the mandibular ramus and potentially interfering with the sectional plane of mandibular distraction osteogenesis. Damage to this vessel could result in inaccessible bleeding. The findings of this study suggest that Göttingen Minipigs are not ideal animal models for experimental mandibular surgery research. Nevertheless if these minipigs are used the authors recommend that radiographic techniques, such as computed tomography, be used in the specific planning procedures for the mandibular surgical experiments. In addition, it is advisable to choose suitable age groups and customize implants based on the mandibular dimensions reported in this study.

3-dimensional visualization of implant-tissue interface with the polyethylene glycol associated solvent system tissue clearing method.

OBJECTIVES: Dental implants are major treatment options for restoring teeth loss. Biological processes at the implant-tissue interface are critical for implant osseointegration. Superior mechanical properties of the implant constitute a major challenge for traditional histological techniques. It is imperative to develop new technique to investigate the implant-tissue interface. MATERIALS AND METHODS: Our laboratory developed the polyethylene glycol (PEG)-associated solvent system (PEGASOS) tissue clearing method. By immersing samples into various chemical substances, bones and teeth could be turned to transparent with intact internal structures and endogenous fluorescence being preserved. We combined the PEGASOS tissue clearing method with transgenic mouse line and other labelling technique to investigate the angiogenesis and osteogenesis processes occurring at the implant-bone interface. RESULTS: Clearing treatment turned tissue highly transparent and implant could be directly visualized without sectioning. Implant, soft/hard tissues and fluorescent labels were simultaneously imaged in decalcified or non-decalcified mouse mandible samples without disturbing their interfaces. Multi-channel 3-dimensional image stacks at high resolution were acquired and quantified. The processes of angiogenesis and osteogenesis surrounding titanium or stainless steel implants were investigated. CONCLUSIONS: Both titanium and stainless steel implants support angiogenesis at comparable levels. Successful osseointegration and calcium precipitation occurred only surrounding titanium, but not stainless steel implants. PEGASOS tissue clearing method provides a novel approach for investigating the interface between implants and hard tissue.

Vascular malformation of the sphenoid and temporal bone: A diagnostic dilemma.

We present a rare case of a vascular anomaly of the sphenoid and temporal bones causing an expandable mass of the temporal region with dependent patient positioning and characteristic osseous changes on imaging. Initial diagnosis considerations included multiple myeloma (MM), fibrous dysplasia (FD), Paget's disease, lymphoma, meningoencephalocele (MEC), and vascular malformation (VaM). VaMs of the head and neck are rare and typically arise in the mandible and maxilla. However, this case demonstrates a unique finding of a VaM of the sphenoid and temporal bones with important radiological features to distinguish the diagnosis of vascular anomaly from other etiologies.