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Understanding the healing process of dental pulp after tooth autotransplantation (TAT) and regenerative endodontic treatment (RET) of immature teeth is important both clinically and scientifically. This study aimed to characterize the pattern of dental pulp healing in human teeth that underwent TAT and RET using state-of-the-art imaging techniques. This study examined 4 human teeth, 2 premolars that underwent TAT, and 2 central incisors that received RET. The premolars were extracted after 1 year (case 1) and 2 years (case 2) due to ankylosis, while the central incisors were extracted after 3 years (cases 3 and 4) for orthodontic reasons. Nanofocus x-ray computed tomography was used to image the samples before being processed for histological and immunohistochemical analysis. Laser scanning confocal second harmonic generation imaging (SHG) was used to examine the patterns of collagen deposition. A maturity-matched premolar was included as a negative control for the histological and SHG analysis. Analysis of the 4 cases revealed different patterns of dental pulp healing. Similarities were observed in the progressive obliteration of the root canal space. However, a striking loss of typical pulpal architecture was observed in the TAT cases, while a pulp-like tissue was observed in one of the RET cases. Odontoblast-like cells were observed in cases 1 and 3. This study provided insights into the patterns of dental pulp healing after TAT and RET. The SHG imaging sheds light on the patterns of collagen deposition during reparative dentin formation. [ABSTRACT FROM AUTHOR]

Abstract Introduction Regenerative endodontic procedures (REP) are a novel treatment modality to restore the function of necrotic pulp tissue via stimulation or transplantation of stem cells into the root canal. This study aimed to investigate the immunohistologic outcome of 3 extracted teeth because of sequelae of trauma and unsatisfactory REP outcomes. Methods Three immature permanent maxillary central incisors of 3 female patients (6–9 years) were extracted 5.5–22 months after REP. Additionally, 1 sound permanent immature central maxillary incisor of 1 of the included patients was extracted for orthodontic reasons. The teeth were immunohistologically stained with Masson's trichrome, neurofilament (NF), pan cytokeratin, dentin sialophosphoprotein, and Gram+/-. Results The REP-teeth presented intracanalar vascularized connective/mineralized reparative tissue (RT), which was less organized than the pulp tissue of the sound tooth. Moderate to considerable calcification was observed below the Portland cement used during REP. In 1 case, the RT was NF+; in the 2 other cases, the periodontal ligament and apical granuloma/papilla were NF+. All teeth were Gram+/- negative; nevertheless, inflammatory cells were present in 2 cases. The pan cytokeratin and dentin sialophosphoprotein stainings were not specific enough for 2 cases. Conclusions This immunohistologic study of failed REP cases resulted in bacteria-free intracanalar RT and biomaterial-induced calcification. Nevertheless, the presence of inflammatory cells revealed a persistent inflammation. Hence, the clinical and radiographic signs were decisive for tooth survival and multidisciplinary outcome determination. [ABSTRACT FROM AUTHOR]

Abstract Despite the fact that external cervical resorption (ECR) is a well-known and rather frequently met condition, the driving force of this phenomenon still remains unclear. Recently, hypoxia has been linked to ECR. Thus, the aim of this work was to investigate the existence of hypoxia in ECR and hypothesize on its role at the time of extraction. This work is a case study of a tooth with ECR. ECR diagnosis was based on clinical and radiographic examination with cone-beam computed tomographic imaging. The extracted tooth was further analyzed by using nanofocus computed tomographic imaging and immunohistology. To investigate the 3-dimensional extent and pattern of ECR, in vivo cone-beam computed tomographic imaging and ex vivo nanofocus computed tomographic imaging were used. Different histologic stains were used to investigate the presence of a hypoxic environment and to gain a better insight into the involved cells, neuronal structures, and remodeling process during ECR. A higher distribution of hypoxia-inducible factor 1a–positive cells was found in the apical part of the resorption area when compared with the coronal area of the resorption. In addition, a similar distribution of hypoxia-inducible factor 1a–positive odontoblasts was observed in the pulp. Three-dimensional analysis of the calcification of the pulp revealed the formation of pulp stones in areas with higher hypoxia. Histology showed that remodeling during ECR can occur according to a layered pattern. This investigation confirms the presence of hypoxia in ECR and shows that there is a gradient of hypoxia within the ECR lesion and surrounding tooth structure. The hypoxic environment within the pulp is also indicated by the formation of pulp stones. [ABSTRACT FROM AUTHOR]

Purpose: The aim was to assess the effect of a relevant regimen of zoledronic acid (ZA) treatment for the study of bisphosphonate-related osteonecrosis of the jaw on alveolar bone microstructure and vasculature. A sub-objective was to use 3-dimensional imaging to describe site-specific changes induced by ZA in the alveolar bone.Materials and Methods: Five Wistar rats received ZA (0.6 mg/kg) and five (controls) received saline solution in the same volume. The compounds were administered intraperitoneally in 5 doses every 28 days. The rats were euthanized 150 days after therapy onset. The mandibles were scanned using high-resolution (14-μm) micro-computed tomography (micro-CT), decalcified, cut into slices for histologic analysis (5 μm), and stained with hematoxylin-eosin. Bone quality parameters were calculated using CT-Analyser software (Bruker, Kontich, Belgium) in 2 different volumes of interest (VOIs): the region between the first molar roots (VOI-1) and the periapical region under the first and second molars' apex (VOI-2). Blood vessel density and bone histomorphometric parameters were calculated only for the region between the roots of the first molar using AxioVision Imaging software (version 4.8; Carl Zeiss, Gottingen, Germany).Results: ZA-treated rats showed a significant increase in percentage of bone volume and density (P < .05), with thicker and more connected trabeculae. Furthermore, the ZA group showed a significant decrease in the size of the marrow spaces and nutritive canals and in blood vessel density (P < .05). In the micro-CT evaluation, VOI-2 showed better outcomes in measuring the effect of ZA on alveolar bone.Conclusions: ZA treatment induced bone corticalization and decreased alveolar bone vascularization. VOI-2 should be preferred for micro-CT evaluation of the effect of bisphosphonates on alveolar bone. This analysis allowed the effect of ZA on alveolar bone and its vascularization to be characterized. The results of this analysis may add further knowledge to the understanding of the physiopathology of osteonecrosis of the jaw. [ABSTRACT FROM AUTHOR]

A major conceptual breakthrough in cell signaling has been the finding of EV as new biomarker shuttles in body fluids. Now, one of the major challenges in using these nanometer-sized biological entities as diagnostic marker is the development of translational methodologies to profile them. SPR offers a promising label-free and real time platform with a high potential for biomarker detection. Therefore, we aimed to develop a uniform SPR methodology to detect specific surface markers on EV derived from patient with CHD. EVs having an approximate size range between 30 and 100 nm (~48.5%) and 100-300 nm (~51.5%) were successfully isolated. The biomarker profile of EV was verified using immunogold labeling, ELISA and SPR. Using SPR, we demonstrated an increased binding of EV derived from patients with CHD to anti-ICAM-1 antibodies as compared to EV from healthy donors. Our current findings open up novel opportunities for in-depth and label-free investigation of EV. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to assess the influence of the number of basis images and the orientation of the skull on the evaluation of cortical alveolar bone in cone beam computed tomography (CBCT).Study Design: Eleven skulls with a total of 59 anterior teeth were selected. CBCT images were acquired by using 4 protocols, by varying the rotation of the tube-detector arm and the orientation of the skull (protocol 1: 360°/0°; protocol 2: 180°/0°; protocol 3: 180°/90°; protocol 4: 180°/180°). Observers evaluated cortical bone as absent, thin, or thick. Direct observation of the skulls was used as the gold standard. Intra- and interobserver agreement, as well as agreement of scoring between the 3 bone thickness classifications, were calculated by using the κ statistic. The Wilcoxon signed-rank test was used to compare the 4 protocols.Results: For lingual cortical bone, protocol 1 showed no statistical difference from the gold standard. Higher reliability was found in protocol 3 for absent (κ = 0.80) and thin (κ = 0.47) cortices, whereas for thick cortical bone, protocol 2 was more consistent (κ = 0.60). In buccal cortical bone, protocol 1 obtained the highest agreement for absent cortices (κ = 0.61), whereas protocol 4 was better for thin cortical plates (κ = 0.38) and protocol 2 for thick cortical plates (κ = 0.40).Conclusions: No consistent effect of the number of basis images or head orientation for visual detection of alveolar bone was detected, except for lingual cortical bone, for which full rotation scanning showed improved visualization. [ABSTRACT FROM AUTHOR]

Hydrogels have emerged as promising biomaterials for regenerative medicine. Despite major advances, tissue engineers have faced challenges in studying the complex dynamics of cell-mediated hydrogel remodelling. Second harmonic generation (SHG) microscopy has been a pivotal tool for non-invasive visualization of collagen type I hydrogels. By taking into account the typical polarization SHG effect, we recently proposed an alternative image correlation spectroscopy (ICS) model to quantify characteristics of randomly oriented collagen fibrils. However, fibril alignment is an important feature in many tissues that needs to be monitored for effective assembly of anisotropic tissue constructs. Here we extended our previous approach to include the orientation distribution of fibrils in cellular hydrogels and show the power of this model in two biologically relevant applications. Using a collagen hydrogel contraction assay, we were able to capture cell-induced hydrogel modifications at the microscopic scale and link these to changes in overall gel dimensions over time. After 24 h, the collagen density was about 3 times higher than the initial density, which was of the same order as the decrease in hydrogel area. We also showed that the orientation parameters recovered from our automated ICS model match values obtained from manual measurements. Furthermore, regions axial to cellular processes aligned at least 1.5 times faster compared with adjacent zones. Being able to capture minor temporal and spatial changes in hydrogel density and collagen fibril orientation, we demonstrated the sensitivity of this extended ICS model to deconstruct a complex environment and support its potential for tissue engineering research. Statement of significance It is generally accepted that looking beyond bulk hydrogel composition is key in understanding the mechanisms that influence the mechanical and biological properties of artificial tissues. In this manuscript, we performed label-free non-invasive imaging and extended a robust automated analysis method to characterize the microstructural organisation of cellular hydrogel systems. We underpin the sensitivity of this technique by capturing minor changes in collagen density and fibril orientation in biologically relevant systems over time. Therefore, we believe that this method is applicable in fundamental cell-matrix research and has high-throughput potential in screening arrays of hydrogel scaffolds, making it an interesting tool for future tissue engineering research. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Perioperative navigation is a recent addition to orthognathic surgery. This study aimed to evaluate the accuracy of anatomical landmarks-based registration. Materials and methods: Eighty-five holes (1.2 mm diameter) were drilled in the surface of a plastic skull model, which was then scanned using a SkyView cone beam computed tomography scanner. DICOM files were imported into BrainLab ENT 3.0.0 to make a surgical plan. Six anatomical points were selected for registration: the infraorbital foramena, the anterior nasal spine, the crown tips of the upper canines, and the mesial contact point of the upper incisors. Each registration was performed five times by two separate observers (10 times total). Results: The mean target registration error (TRE) in the anterior maxillary/zygomatic region was 0.93 ± 0.31 mm (p < 0.001 compared with other anatomical regions). The only statistically significant inter-observer difference of mean TRE was at the zygomatic arch, but was not clinically relevant. Conclusion: With six anatomical landmarks used, the mean TRE was clinically acceptable in the maxillary/zygomatic region. This registration technique may be used to access occlusal changes during bimaxillary surgery, but should be used with caution in other anatomical regions of the skull because of the large TRE observed. [Copyright &y& Elsevier]

Objective: To compare the outcome of cone beam computed tomography (CBCT)-based surgical planning and transfer technique for tooth autotransplantation versus conventional autotransplantation. Study Design: The study material comprised 40 pediatric subjects in whom 48 teeth were transplanted following a case-control design. While the study group (mean age 11 years) underwent CBCT imaging for surgical planning and transfer via stereolithographic tooth replica fabrication, the historical control group (mean age 12 years) was subjected to conventional autotransplantation. Results: The CBCT-based preoperative planning and the use of a tooth replica decreased the extra-alveolar time and reduced the number of positioning trials with the donor tooth. In the control group, 6 patients showed 1 or more complications, while this was noticed for only 2 study patients. Conclusion: CBCT-based surgical planning of tooth autotransplantation may benefit from a shorter surgical time, while being a less invasive technique, causing fewer failures than a conventional approach. [ABSTRACT FROM AUTHOR]

Objective: To compare the outcome of cone beam computed tomography (CBCT)–based surgical planning and transfer technique for tooth autotransplantation versus conventional autotransplantation. Study Design: The study material comprised 40 pediatric subjects in whom 48 teeth were transplanted following a case–control design. While the study group (mean age 11 years) underwent CBCT imaging for surgical planning and transfer via stereolithographic tooth replica fabrication, the historical control group (mean age 12 years) was subjected to conventional autotransplantation. Results: The CBCT-based preoperative planning and the use of a tooth replica decreased the extra-alveolar time and reduced the number of positioning trials with the donor tooth. In the control group, 6 patients showed 1 or more complications, while this was noticed for only 2 study patients. Conclusion: CBCT-based surgical planning of tooth autotransplantation may benefit from a shorter surgical time, while being a less invasive technique, causing fewer failures than a conventional approach. [Copyright &y& Elsevier]

Purpose: Defects at the lower border of the mandible may persist after bilateral sagittal split osteotomy (BSSO). The purpose of this study was to estimate the frequency of lower border defects after BSSO and to identify factors associated with the development of these defects. Materials and Methods: This retrospective study included patients who underwent BSSO at St John''s Hospital from January 2010 through December 2011. The predictor variables were length of advancement and inclusion of the full thickness of the lower border in the split. The outcome variable was the presence or absence of a lower border defect. Other variables were age and the side of the mouth. All analyses were performed using SAS 9.22. Results: The analysis included 400 operation sites in 200 patients (124 female, 76 male; median age, 24.5 yr; range, 14 to 57 yr). A defect at the mandibular border presented in more than one third of operation sites. Inclusion of the full thickness of the lower border in the split, length of advancement, side of the jaw, and age (P < .0001) were risk factors for a permanent defect at the lower border of the osteotomy gap after BSSO. Conclusions: Inclusion of the full thickness of the lower mandibular border, the age of the patient, and the magnitude of advancement during BSSO are important predictors of whether a postoperative mandibular defect will remain after surgery. Surgeons should ensure that the lingual cortex of the lower border is not included in the split in large mandibular advancements. [Copyright &y& Elsevier]

Objectives: The objectives of this study were to analyze outcomes with miniplates in orthognathic surgery and define risk factors resulting in plate removal. Study design: Clinical files of 570 orthognathic surgery patients operated between 2004 and 2009 were reviewed: 203 had a bimaxillary operation, 310 a lower jaw osteotomy, and 57 an upper jaw osteotomy. Age, sex, and jaw movement were analyzed. Reasons for hardware removal were recorded. Results: Hardware was removed in 157 patients (27.5%). Seventy-eight patients (13.7%) needed removal because of plate-related infection; 66 (11.6%) because of clinical irritation; 5 (0.9%) for dental implant placement; and 8 (1.4%) for other reasons. Average time between operation and removal was 9.9 months. More women (31.7%) than men (20.3%) had plates removed, but age was not a factor except with infection. Conclusions: More than a quarter of patients developed complications from plates and screws, necessitating their removal, and infection occurred in 13.7%. Prompt removal constituted adequate management. [ABSTRACT FROM AUTHOR]

Objectives: The objectives of this study were to determine the incidence of bad splits in sagittal split osteotomies (SSOs), performed at the same hospital, and if the occurrence was reduced over time because of technical progress and/or surgical experience. Bad splits were defined as buccal or lingual plate fractures. Study design: The files of all patients (n = 1008) who underwent bilateral or unilateral SSO between October 1989 and October 2009 were reviewed retrospectively. Results: A bad split occurred in 14 SSO sites (14 of 2005 sites). No bilateral bad splits occurred. There was no notable decrease of bad splits over the 20 years. All bad splits were resolved perioperatively by plate-osteosynthesis without the additional need of intermaxillary fixation. All patients with a bad split had a good and functional occlusion 6 months postoperatively. No infections occurred at the site of the bad splits. No bad splits occurred in patients younger than 20 years. No particular type of dental-facial deformity, or skeletal class according to the Angle''s classification could be correlated with cases of bad splits as a predisposing risk factor. Conclusion: Even if precautions are taken, a bad split can occur during SSO of the mandible. This complication is manageable because of its low incidence (0.7 % of all SSOs) and uneventful healing. A significant decrease in incidence did not occur during the 20-year period, and neither technical progress nor the surgeon''s experience further reduced the incidence of bad splits. [Copyright &y& Elsevier]

The anterior jaw bones are often considered relatively safe surgical sites. Nonetheless, the increasing rate of surgical interventions in that area, such as oral implant placement and bone grafting, has highlighted the potential risks and has raised the reported complications. A careful documentation of all anatomic variations in anterior jaw bone neurovascularization has thus become necessary. The present report attempts to revisit jaw bone neurovascularization, addressing typical anatomic appearances and variations. We summarize the results of various microanatomical studies carried out by high-resolution magnetic resonance imaging (HR-MRI) of the human anterior jaw bones. These studies reveal that edentulous and dentate anterior jaws present significant variation in the occurrence of the mandibular incisive canal and genial spinal foramina, as well as the maxillary nasopalatine canal. All of these canal structures contain a neurovascular bundle, whose diameter may be large enough to cause clinically significant trauma. A careful presurgical radiographic analysis of the anterior jaw bones is therefore advised. [Copyright &y& Elsevier]

Trigeminal neuralgia is characterized by unilateral pain in the region supplied by the sensory distribution of the fifth cranial nerve. Pharmacologic therapy is an adequate initial treatment option in 75% of patients. When the Jannetta surgical operation is not available or not indicated and when conservative treatment fails to relieve the pain or the medication has to be discontinued because of side effects, one of the remaining surgical options is cryosurgery in the peripherally distributed nerves that emanate from the trigeminal nerve. This technical note describes a perioperative method for exposing and mobilizing the inferior alveolar nerve (IAN) from its bony canal. This approach provided easy access to infratemporal fossa structures during cryotherapy. This technique represented a further development of the technique previously described by the authors. This method ensured direct visualization of the IAN and wide access to theinfratemporal fossa during IAN cryotherapy. [ABSTRACT FROM AUTHOR]

Introduction Compelling evidence pinpoints that pulp tissue engineering after the transplantation of stem cells is possible. Although intriguing, severe problems regarding clinical feasibility remain. Cell homing has been proposed as a viable alternative in which dentin-derived growth factors in a conducive scaffold may attract resident cells to form pulplike tissue. In this study, an ectopic animal model for in situ dental pulp tissue engineering was developed to evaluate whether pulplike tissue formation in empty root canals after the attraction of stem cells was possible and whether this could be enhanced by dentin-derived growth factors. Methods Three types of fibrin (custom-made fibrin, fibrin sealant, and plasma rich in growth factors [PRGF]) as well as a self-assembling peptide were evaluated in vivo in a modified tooth root model using human teeth. Root canal dentin was conditioned with EDTA, tooth roots were filled with growth factor–laden scaffolds, and dental pulp stem cells in collagen were placed at the root tip. Constructs were implanted into immunocompromised mice for 4 weeks and subsequently analyzed histologically. Differential interference contrast and second harmonic generation imaging were performed for selected sections. Results For custom-made fibrin and fibrin sealant with dentin matrix proteins, migration into the roots and the formation of a pulplike tissue were observed, whereas the peptide-based scaffold appeared less suitable. PRGF supported tissue formation regardless of the addition of dentin matrix proteins. In the test groups with dentin matrix proteins and EDTA conditioning, differentiated odontoblastlike cells extended cellular processes into the dentinal tubules, which coincided with the deposition of the newly formed collagenous dentin matrix. Conclusions This new cell homing model provides evidence that fibrin derivatives make applicable scaffolds and that dentin-derived proteins induce chemotaxis and pulplike tissue formation. [ABSTRACT FROM AUTHOR]

Dental pulp is a highly vascularized and innervated tissue containing a heterogeneous stem cell population with multilineage differentiation potential. Current endodontic treatments focus on the preservation of the pulp tissue and the regeneration of dental pulp after pathological insults. Human dental pulp stem cells (hDPSCs) are currently investigated as stem cell–based therapy for pulp regeneration and for peripheral nerve injury in which neurons and Schwann cells display limited regenerative capacity. We have developed a neuronal differentiation protocol for hDPSCs that requires neurosphere formation before neuronal maturation. Moreover, Schwann cell differentiation of hDPSCs in our group revealed that differentiated hDPSCs have acquired the ability to myelinate and guide neurites from dorsal root ganglia. Besides their dynamic differentiation capacity, hDPSCs were shown to exert a paracrine effect on neural and endothelial cells. Analysis of hDPSC conditioned medium revealed the secretion of a broad spectrum of growth factors including brain-derived neurotrophic factor, nerve growth factor, vascular endothelial growth factor, and glial-derived neurotrophic factor. Application of the conditioned medium to endothelial cells promoted cell migration and tubulogenesis, indicating a paracrine proangiogenic effect. This hypothesis was enforced by the enhanced formation of blood vessels in the chorioallantoic membrane assay in the presence of hDPSCs. In addition, transplantation of 3-dimensional–printed hydroxyapatite scaffolds containing peptide hydrogels and hDPSCs into immunocompromised mice revealed blood vessel ingrowth, pulplike tissue formation, and osteodentin deposition suggesting osteogenic/odontogenic differentiation of hDPSCs. Future studies in our research group will focus on the pulp regeneration capacity of hDPSCs and the role of fibroblasts within the pulp extracellular matrix. [ABSTRACT FROM AUTHOR]

Objective: This study assesses the incidence of neuropathic pain after orthognathic surgery at our center and briefly reports the cases found. Study Design: All records of orthognathic surgical patients between 2001 and 2011 were exported from the hospital information system into a Portable Document Format platform (Adobe Acrobat) to simplify keyword searching. Records of patients that developed debilitating chronic pain were isolated and examined. Results: Records included 982 bilateral sagittal split osteotomies, 536 LeFort I procedures, and 335 surgically assisted rapid palatal expansion procedures. Six records were identified that described cases in which patients developed debilitating chronic neuropathic pain after orthognathic surgery (mean age at surgery, 43 years). Conclusions: The exposure of the inferior alveolar nerve or partial axonal injury together with a disruption of the bony environment of the inferior alveolar nerve is a risk factor after bilateral sagittal split osteotomy. [ABSTRACT FROM AUTHOR]