Macrophage Polarization and Alveolar Bone Healing Outcome: Despite a Significant M2 Polarizing Effect, VIP and PACAP Treatments Present a Minor Impact in Alveolar Bone Healing in Homeostatic Conditions.

Host inflammatory immune response comprises an essential element of the bone healing process, where M2 polarization allegedly contributes to a favorable healing outcome. In this context, immunoregulatory molecules that modulate host response, including macrophage polarization, are considered potential targets for improving bone healing. This study aims to evaluate the role of the immunoregulatory molecules VIP (Vasoactive intestinal peptide) and PACAP (Pituitary adenylate cyclase activating polypeptide), which was previously described to favor the development of the M2 phenotype, in the process of alveolar bone healing in C57Bl/6 (WT) mice. Experimental groups were submitted to tooth extraction and maintained under control conditions or treated with VIP or PACAP were evaluated by microtomographic (µCT), histomorphometric, immunohistochemical, and molecular analysis at 0, 3, 7, and 14 days to quantify tissue healing and host response indicators at the healing site. Gene expression analysis demonstrates the effectiveness of VIP or PACAP in modulating host response, evidenced by the early dominance of an M2-type response, which was paralleled by a significant increase in M2 (CD206+) in treated groups. However, despite the marked effect of M1/M2 balance in the healing sites, the histomorphometric analysis does not reveal an equivalent/corresponding modulation of the healing process. µCT reveals a slight increase in bone matrix volume and the trabecular thickness number in the PACAP group, while histomorphometric analyzes reveal a slight increase in the VIP group, both at a 14-d time-point; despite the increased expression of osteogenic factors, osteoblastic differentiation, activity, and maturation markers in both VIP and PACAP groups. Interestingly, a lower number of VIP and PACAP immunolabeled cells were observed in the treated groups, suggesting a reduction in endogenous production. In conclusion, while both VIP and PACAP treatments presented a significant immunomodulatory effect with potential for increased healing, no major changes were observed in bone healing outcome, suggesting that the signals required for bone healing under homeostatic conditions are already optimal, and additional signals do not improve an already optimal process. Further studies are required to elucidate the role of macrophage polarization in the bone healing process.

Complex Dentoalveolar Fractures: Main Clinical Variables Description and Analysis.

AIMS AND OBJECTIVES: To analyze and evaluate clinical features that define complex dentoalveolar trauma. MATERIALS AND METHODS: Forty-five patients, with a mean age of 36.1 years, were included in the study; most patients were male (82.2%). The main clinical features defining dentoalveolar fractures were evaluated, including the status of the tooth, alveolar socket and adjacent soft tissues and their relationships with tooth loss. The relationship between splinting and tooth loss was also studied. The data were analyzed using descriptive and statistical methods. RESULTS: A significant relationship was observed between the different clinical variables and tooth loss, in particular the status of the alveolar socket as the most relevant clinical factor; there was also a significant relationship between splinting and tooth loss, as this was the main protective factor. CONCLUSIONS: Tooth loss prognosis following complex dentoalveolar trauma is related to the clinical features of the fracture, particularly the status of the alveolar socket and the possibility of using splinting as treatment.

Regeneration of a Pediatric Alveolar Cleft Model Using Three-Dimensionally Printed Bioceramic Scaffolds and Osteogenic Agents: Comparison of Dipyridamole and rhBMP-2.

BACKGROUND: Alveolar clefts are traditionally treated with secondary bone grafting, but this is associated with morbidity and graft resorption. Although recombinant human bone morphogenetic protein-2 (rhBMP-2) is under investigation for alveolar cleft repair, safety concerns remain. Dipyridamole is an adenosine receptor indirect agonist with known osteogenic potential. This study compared dipyridamole to rhBMP-2 at alveolar cleft defects delivered using bioceramic scaffolds. METHODS: Skeletally immature New Zealand White rabbits underwent unilateral, 3.5 × 3.5-mm alveolar resection adjacent to the growing suture. Five served as negative controls. The remaining defects were reconstructed with three-dimensionally printed bioceramic scaffolds coated with 1000 µm of dipyridamole (n = 6), 10,000 µm of dipyridamole (n = 7), or 0.2 mg/ml of rhBMP-2 (n = 5). At 8 weeks, new bone was quantified. Nondecalcified histologic evaluation was performed, and new bone was evaluated mechanically. Statistical analysis was performed using a generalized linear mixed model and the Wilcoxon rank sum test. RESULTS: Negative controls did not heal, whereas new bone formation bridged all three-dimensionally printed bioceramic treatment groups. The 1000-µm dipyridamole scaffolds regenerated 28.03 ± 7.38 percent, 10,000-µm dipyridamole scaffolds regenerated 36.18 ± 6.83 percent (1000 µm versus 10,000 µm dipyridamole; p = 0.104), and rhBMP-2-coated scaffolds regenerated 37.17 ± 16.69 percent bone (p = 0.124 versus 1000 µm dipyridamole, and p = 0.938 versus 10,000 µm dipyridamole). On histology/electron microscopy, no changes in suture biology were evident for dipyridamole, whereas rhBMP-2 demonstrated early signs of suture fusion. Healing was highly cellular and vascularized across all groups. No statistical differences in mechanical properties were observed between either dipyridamole or rhBMP-2 compared with native bone. CONCLUSION: Dipyridamole generates new bone without osteolysis and early suture fusion associated with rhBMP-2 in skeletally immature bone defects.

Combined orthodontic, surgical, and restorative approach to treat a complicated crown-root fracture in a maxillary central incisor.

This case report shows the treatment of a severe traumatic tooth injury. For the maxillary right central incisor, the trauma was considered a complicated crown-root fracture. The level of the fracture line, the length of the remaining root segment, and the presence and condition of the tooth fragment determined the type of therapy. Traumatized teeth with fractures below the alveolar crest are often considered hopeless. As this report shows, the treatment of a complicated crown-root fracture in the esthetic region can be challenging. Orthodontic extrusion and crown-length surgery were performed to bring the fracture line above the alveolar bone crest. A multidisciplinary approach was required for complete rehabilitation of the traumatized maxillary incisor. Suggestions are made to improve treatment planning of complicated crown-root fractures.

Nanofibrous yarn reinforced HA-gelatin composite scaffolds promote bone formation in critical sized alveolar defects in rabbit model.

Alveolar ridge resorption and crestal bone loss necessitate the use of bone graft substitutes for dental rehabilitation. The aim of this study was to compare the bone regenerative property of nanofibre incorporated two composite matrices (nanofibrous sheet layered matrix (CS-S) and nanofibrous yarn reinforced matrix (CS-Y)) in critical sized mandibular defect in a rabbit model (under load bearing scenario). Histological evaluation revealed continuous bone formation in the defect implanted with fibre reinforced scaffolds than those without fibres as well as commercial nanoHA-collagen graft. Interestingly, the mineralisation and the mineral density were significantly higher with nanoyarn reinforced scaffolds. Moreover, the compressive strength of new bone formed from CS-Y scaffolds was almost similar to that of native rabbit mandible. It can be concluded that the mechanical strength provided by three-dimensionally reinforced nanoyarns in the matrix could promote bone formation in load bearing mandibular region, and these can be proposed as a scaffold of choice for alveolar bone augmentation and dental rehabilitation.

Low-intensity pulsed ultrasound promotes alveolar bone regeneration in a periodontal injury model.

Periodontitis is a common oral disease characterized by progressive destruction of periodontal tissue and loss of teeth. However, regeneration of periodontal tissue is a time-consuming process. Low-intensity pulsed ultrasound (LIPUS) is a widely used non-invasive intervention for enhancing bone healing in fractures and non-unions. With the hypothesis that LIPUS may accelerate periodontal regeneration, the effects of LIPUS on periodontal tissue regeneration were investigated both in vitro and in vivo. LIPUS (90 mw/cm2, 20 min/d, 1.5 MHz) was applied to stimulate dog periodontal ligament cells (dPDLCS). The mRNA expression of BSP (P < 0.05), OPN (P < 0.05) and COL3 (P < 0.05) was increased significantly in the LIPUS group. The positive stained mineralized nodules by alizarin red in the LIPUS group were greater than in the control group (P < 0.05). Eight male beagle dogs were divided into 4 groups: guided tissue regeneration (GTR) group (G1), LIPUS + GTR group (G2), LIPUS group (G3), and control group (G4, no treatment). A 4 × 5 mm2 defect was created in the buccal alveolar bone. The modeling areas in the G2 and G3 groups were then exposed to LIPUS. Eight weeks after surgery, histological assessment indicated increased periodontal tissue in the LIPUS + GTR group. Micro computed tomography (micro-CT) showed that the regenerated bone volume (BV) in the G2 was significantly higher than that in the G1, G3 and G4 groups (P < 0.05). The bone surface (BS) trabecular number (Tb.N) and trabecular thickness (Tb.Th) in G2 were markedly higher than in G4 (P < 0.05). It is concluded that LIPUS + GTR can accelerate new alveolar bone formation, with a prospective for promoting periodontal tissue repair.

Maxillary Interdental Osteotomies Have Low Morbidity for Alveolar Crestal Bone and Adjacent Teeth: A Cone Beam Computed Tomography-Based Study.

PURPOSE: Maxillary segmentation involving interdental osteotomies can have an adverse effect on the interdental crestal bone and adjacent teeth. The purpose of the present study was to evaluate the effect of interdental osteotomies on surrounding osseous and dental structures, including adjacent teeth, using cone beam computed tomography (CBCT), in patients who underwent segmental maxillary osteotomies. PATIENTS AND METHODS: The present retrospective cohort study evaluated interdental osteotomy (IDO) sites between the lateral incisors and canines in patients treated with 3-piece Le Fort I osteotomies. CBCT scans were assessed using Kodac Dental Imaging software at specific intervals: T0 (before surgery), T1 (immediately after surgery), and T2 (a minimum of 11 months after surgery). The statistical analysis using a linear regression model was adjusted to compare the variables at the different intervals. Injury to the dental structures was assessed by radiological evidence of dental damage, the requirement for endodontic treatment, or tooth loss. RESULTS: We evaluated 94 IDO sites in 47 patients in the present study. The mean inter-radicular distance at T0 was 2.5 mm. A statistically significant increase was seen in the inter-radicular distance (between T1 and T0) of 0.72 mm, with a reduction of the alveolar bone crest height (between T2 and T0) of 0.19 mm (P < .001) for the group that underwent IDO. A weak correlation was found for this increase in the inter-radicular distance, with changes in the alveolar crest bone height. The potential complications associated with interdental osteotomies such as iatrogenic damage to the tooth structure, the need for endodontic treatment, and tooth loss were not encountered in any patients. CONCLUSIONS: We found very low morbidity for the interdental alveolar crest and the integrity of teeth adjacent to interdental osteotomies for patients who underwent maxillary segmentation between the lateral incisors and canines.

Analysis of dental injuries with clinical implications: A forensic case report.

Dental injuries, especially of the incisors, caused by punches in violent criminal attacks could be seen in daily forensic casework involving the identification of injuries to a living body. Sometimes, when there is neither circumstantial evidence nor information about the surrounding circumstances, it is difficult to discern the cause of these injuries and the manner in which they were inflicted. As an example of clinical forensic medicine, we present the case of a 58-year-old woman whose teeth were injured when fighting with her son-in-law over household affairs with no witnesses present. The two parties had conflicting stories about the cause of the woman's injury. The woman claimed that her teeth were lost while she was being beaten by her son-in-law, and the man argued that the damage to his mother-in-law's teeth was self-inflicted when she bit his fingers. The police attending the crime called for a forensic examination. Forensic practitioners analysed the mechanism of the tooth loss using multi-slice spiral computed tomography (MSCT) and imaging reconstruction technology. Local alveolar bone (medial alveolar) fracture and a small area of alveolar bone loss were found on MSCT. Thus, forensic medical experts speculated that the woman's lower central and lateral incisors were lost as a result of a violent attack and were not self-inflicted. Finally, forensic practitioners helped police in avoiding a miscarriage of justice and wrongful conviction.

Periodontal Blood Flow Protects the Alveolar Bone from Thermal Injury during Thermoplasticized Obturation: A Finite Element Analysis Study.

INTRODUCTION: The purpose of this study was to investigate the heat transfer during thermoplastic obturation and the cooling capacity of blood flow in the periodontal ligament (PDL) using finite element analysis (FEA). METHODS: A 3-dimensional digital tooth model was constructed based on micro-computed tomographic scanning of a mandibular first molar after chemomechanical preparation in vitro. A layer of PDL with or without simulated blood flow was built on the root portion of the tooth in software. Two heat-assisted obturation techniques (ie, the single-wave condensation technique and the warm vertical compaction technique followed by backfilling with injectable gutta-percha) were examined using an FEA package. RESULTS: In the model without blood flow, the highest temperature at the alveolar bony aspect of the PDL was 50.0°C along the distal canal and 52.5°C for the mesiolingual canal when the single-wave technique was used. With the warm vertical compaction technique, the highest temperature was 47.3°C for the distal canal and 47.8°C for the mesiolingual canal. In the model with simulated periodontal blood flow, a notable drop in the peak temperatures at the root surface and at the adjoining alveolar bone was observed for both the distal and mesiolingual canals; all peak temperatures at the PDL fell below 47°C regardless of the obturation techniques used. The greatest rise in temperature was situated at the furcation aspect of the middle third of both roots. CONCLUSIONS: The cooling capacity of blood flow in the PDL is a factor that must be considered in the investigation of heat transfer during thermoplastic obturation.

Custom Repair of Mandibular Bone Defects with 3D Printed Bioceramic Scaffolds.

Implanting artificial biomaterial implants into alveolar bone defects with individual shape and appropriate mechanical strength is still a challenge. In this study, bioceramic scaffolds, which can precisely match the mandibular defects in macro and micro, were manufactured by the 3-dimensional (3D) printing technique according to the computed tomography (CT) image. To evaluate the stimulatory effect of the material substrate on bone tissue regeneration in situ in a rabbit mandibular alveolar bone defect model, implants made with the newly developed, mechanically strong ~10% Mg-substituted wollastonite (Ca90%Mg10%SiO3; CSi-Mg10) were fabricated, implanted into the bone defects, and compared with implants made with the typical Ca-phosphate and Ca-silicate porous bioceramics, such as ß-tricalcium phosphate (TCP), wollastonite (CaSiO3; CSi), and bredigite (Bred). The initial physicochemical tests indicated that although the CSi-Mg10 scaffolds had the largest pore dimension, they had the lowest porosity mainly due to the significant linear shrinkage of the scaffolds during sintering. Compared with the sparingly dissolvable TCP scaffolds (~2% weight loss) and superfast dissolvable (in Tris buffer within 6 wk) pure CSi and Bred scaffolds (~12% and ~14% weight loss, respectively), the CSi-Mg10 exhibited a mild in vitro biodissolution and moderate weight loss of ~7%. In addition, the CSi-Mg10 scaffolds showed a considerable initial flexural strength (31 MPa) and maintained very high flexural resistance during soaking in Tris buffer. The in vivo results revealed that the CSi-Mg10 scaffolds have markedly higher osteogenic capability than those on the TCP, CSi, and Bred scaffolds after 16 wk. These results suggest a promising potential application of customized CSi-Mg10 3D robocast scaffolds in the clinic, especially for repair of alveolar bone defects.

Application of Platelet-Rich Fibrin and Injectable Platelet-Rich Fibrin in Combination of Bone Substitute Material for Alveolar Ridge Augmentation - a Case Report.

BACKGROUND: Different barrier membranes and augmentation techniques are used in oral surgery to recover lost bone structures with varied success. Recently, a combination between bone graft materials and Platelet-Rich-Fibrin (PRF) is implemented in the periodontology and implantology. AIM: The aim of this case report was to assess the possibility for augmentation of the alveolar ridge in the frontal region of the upper jaw, utilizing a combination of bone graft material, injectable platelet-rich-fibrin (i-PRF) and advanced platelet-rich fibrin (A-PRF). MATERIALS AND METHODS: An 18 year-old male with expulsion of tooth 11 and partial fracture of the alveolar ridge was treated with augmentation of the alveolar ridge using bone graft material, injectable platelet-rich-fibrin(i-PRF) and advanced platelet-rich-fibrin (A-PRF). Clinical results were reviewed 4 months after the augmentation and a dental implant was placed. RESULTS: The postoperative period was uneventful. The control CBCT scan showed good organization of new bone allowing placement of a dental implant. CONCLUSION: The successful clinical and radiographic results of the case suggest that using A-PRF and i-PRF can be beneficial for bone augmentation of the alveolar ridge before implant placement.

Success rates and complications of autologous onlay bone grafts and sinus lifts in patients with congenital hypodontia and after trauma.

Autogenous bone remains the gold standard for augmentation of the alveolar ridge in congenital hypodontia and appreciable post-traumatic deformity. This generally reflects the volume of material required for such defects and the osteogenic potential of the grafts. Morbidity at the donor site and success rates may lead to autogenous grafts being superseded by xenografts or alloplastic materials in the future, but we know of little evidence to confirm this. All patients having augmentation of the alveolar ridge or sinus lift to enable subsequent placement of implants between 01 January 2009 and 31 December 2016 were identified from a prospectively-gathered database held at the Queen Elizabeth Hospital, Birmingham. Morbidity was recorded, with overall success defined as a graft that enabled subsequent placement of an implant. During this period the following grafts: calvarial (n=4), iliac crest (n=4), and ramus (n=149) were recorded, as well as 53 sinus lifts. Sinus lift augmentation with BioOss® had the highest success rate (51/53). Calvarial and iliac crest grafts had higher failure rates (2/4 and 3/4, respectively) than those from the mandibular ramus (6/149, 4%). Fifteen of 149 (10%) ramus grafts resulted in transient anaesthesia of the inferior alveolar nerve but no patients developed any permanent morbidity at the donor or recipient sites. Ramus grafts are a predictable method of bone augmentation with only transient morbidity at the donor site. Higher failure rates for extraoral grafts probably reflect their use in more challenging cases when more bone is required. Bilateral ramus grafts are an alternative to extraoral grafts and may be supplemented by bovine-derived particulate grafts with no appreciable increase in complications.

Eva Vacuum-Formed Alternative Splinting of Alveolar Fractures in Primary Dentition: A Case Report.

Alveolar fractures treatment includes repositioning of displaced segments and splinting. In children, splinting procedures may occasionally present clinical problems resulting from fewer teeth available for splinting or presence of occlusal disturbances. An alternative clinical approach for splinting in alveolar fractures of primary dentition is described. CLINICAL CASE: A 4.5-year-old girl was referred to our clinic 8 hours after a fall accident. Clinical examination revealed mandibular alveolar process segmental fracture in the right canine area with frontal dislodgement of the labial cortical bone resulting to occluding inability. The area was anaesthetized, cleaned and the dislodged bone was manually repositioned, followed by an EVA copolymer splint for fixation as a result of patient's deep bite impeding regular wire-composite splint. The cap splint that was fabricated on a cast made after an alginate impression, was set on the mandibular dentition and immobilized in the primary molars with acid-etch adhesive and flowable resin composite. Following splint removal after 4 weeks and follow-up visits, successful healing was observed clinically and radiographically with no pathological signs and symptoms. CONCLUSION: The described alternative splinting method in alveolar fractures of primary dentition is a valuable clinical tool for peediatric dentists, easily accepted by children in cases where regular splinting methods cannot be used.

Mineral trioxide aggregate improves healing response of periodontal tissue to injury in mice.

BACKGROUND AND OBJECTIVE: Mineral trioxide aggregate (MTA) is a biomaterial used in endodontic procedures as it exerts beneficial effects on regenerative processes. In this study, we evaluate the effect of MTA on healing of periodontal ligament (PDL) and surrounding tissue, following injury, in a transgenic mouse model and on the differentiation of murine mesenchymal progenitor cells in vitro. MATERIAL AND METHODS: We used an inducible Cre-loxP in vivo fate mapping approach to examine the effects of MTA on the contributions of descendants of cells expressing the αSMA-CreERT2 transgene (SMA9+ ) to the PDL and alveolar bone after experimental injury to the root furcation on the maxillary first molars. Col2.3GFP was used as a marker to identify mature osteoblasts, cementoblasts and PDL fibroblasts. The effects of MTA were examined 2, 17 and 30 days after injury and compared histologically with sealing using an adhesive system. The effects of two dilutions of medium conditioned with MTA on proliferation and differentiation of mesenchymal progenitor cells derived from bone marrow (BMSC) and periodontal ligament (PDLC) in vitro were examined using the PrestoBlue viability assay, alkaline phosphatase and Von Kossa staining. The expression of markers of differentiation was assessed using real-time PCR. RESULTS: Histological analyses showed better repair in teeth restored with MTA, as shown by greater expansion of SMA9+ progenitor cells and Col2.3GFP+ osteoblasts compared with control teeth. We also observed a positive effect on differentiation of SMA9+ progenitors into osteoblasts and cementoblasts in the apical region distant from the site of injury. The in vitro data showed that MTA-conditioned medium reduced cell viability and osteogenic differentiation in both PDLC and BMSC, indicated by reduced von Kossa staining and lower expression of osteocalcin and bone sialoprotein. In addition, cultures grown in the presence of MTA had marked decreases in SMA9+ and Col2.3GFP+ areas as compared with osteogenic medium, confirming reduced osteogenesis. CONCLUSION: MTA promotes regeneration of injured PDL and alveolar bone, reflected as contribution of progenitors (SMA9+ cells) into osteoblasts (Col2.3GFP+ cells). In vitro, MTA-conditioned medium fails to promote osteogenic differentiation of both PDLC and BMSC.

Alveolar Fracture Caused by Tooth Extraction at Home.

Injuries to the teeth and surrounding structures are relatively common. Although traumatic injuries caused by falls or activities related to sports are widely discussed, the same cannot be said regarding accidents arising from non-professional extraction of primary teeth. The present study reports a 6-year-old male child who underwent mandibular alveolar bone fracture during non-professional extraction of his central lower left incisor at home, performed by his 30-year-old aunt. The root of the tooth was with an irregular physiological resorption, which acted as a lever component for the mechanical force applied, leading to bone fracture. Although not common, the possibility that dental roots with irregular resorption can act as a possible risk factor for accidents if the parents or guardians of children during the period of transitional dentition try to perform intentional extraction of primary teeth should be highlighted. Parents should always consult a professional, preferably a pediatric dentist, for monitoring this period of transitional dentition.

Tooth autotransplantation as a pillar for 3D regeneration of the alveolar process after severe traumatic injury: A case report.

In dental traumatology, the loss of teeth and the supporting alveolar bone in children compromise the proper development of maxillofacial structures and also limit the solutions that can be offered. In this case report, multidisciplinary management is described of a child with a significant loss of alveolar bone and associated teeth due to a traffic accident at 8 years of age. The management involved staged teeth autotransplantation into surgically prepared sites with bone expanders, orthodontic treatment and dental implants. The 3D regeneration of the alveolar process was successfully stimulated by teeth autotransplantation. At the 4-year follow-up visit, evaluation of the autotransplanted teeth and the implants indicated a successful outcome for the patient.

A retrospective study of isolated fractures of the alveolar process in the permanent dentition.

BACKGROUND/AIM: There is a lack of studies of fractures of the alveolar process (FAP). Only five were published in the last 50 years. The aim of this study was to analyze the risk of pulp necrosis and infection (PN), pulp canal obliteration (PCO), infection-related root resorption (IRR), ankylosis-related resorption (ARR), marginal bone loss (MBL), and tooth loss (TL) as well as to identify the possible risk factors for teeth involved in an isolated alveolar process fracture. In the second part, any late complications of the involved teeth were reported in patients who responded to a follow-up examination. MATERIAL AND METHOD: This study was a retrospective analysis of 126 patients with 329 traumatized permanent teeth treated in a regional dental trauma clinic. Follow-up examination was performed on 31 (24.6%) patients with 75 (22.8%) teeth. The risks of PN, PCO, RR, MBL, and TL were analyzed using the Kaplan-Meier method. Possible risk factors for PN (stage of root development, fracture position in relation to the root apex, concomitant injury, treatment delay, and antibiotics) were analyzed using univariate and multivariate Cox regression and generalized estimating equation. The level of significance was 5%. RESULTS: Pulp necrosis was observed in 43% of the teeth, and it was significantly associated with the presence of a concomitant injury and complete root formation. PCO was recorded in 2.8%, root resorption (RR, IRR, and ARR) in 4%, MBL in 8%, and TL in 0.6% of the teeth. Thirty-four percent of the teeth were assumed to have normal pulps, but they did not respond to pulp sensibility testing. At the follow-up examination, PN was found in 49%, PCO in 28%, RR (IRR and ARR) in 4%, MBL in 17%, and TL in 5%. Estimated risk after a 5-years follow up was as follows: PN: 48.2% (95% confidence interval (CI): 42.0-54.5), IRR: 7.2 (95% CI: 3.5-10.9), ARR: 33.0% (95% CI: 22.4-43.6), BL: 16.7% (95% CI: 9.6-23.8), TL: 4.0% (95% CI: 0.0-8.5). The following factors significantly increased the risk of PN: mature root development (hazard ratio [HR]: 7.50 [95% CI: 1.84-30.64], P=.005) and concomitant injury (HR: 2.68 [95% CI: 1.76-4.09], P<.001). In a logistic regression model, teeth with mature roots had a threefold risk of becoming non-responsive to pulp testing. CONCLUSION: Teeth involved in an isolated alveolar process fracture and managed with a conservative treatment approach appear to have a good prognosis. The most common complication was PN which did not negatively affect the survival of the teeth after root canal treatment.

Accelerated bony defect healing based on chitosan thermosensitive hydrogel scaffolds embedded with chitosan nanoparticles for the delivery of BMP2 plasmid DNA.

Regeneration of alveolar bone is among the main purposes of periodontal treatment. However, it is a challenge for both dentists and patients. An injectable chitosan-based thermosensitive hydrogel scaffold (CS/CSn-GP) was successfully designed and prepared with the incorporation of bone morphogenetic protein-2 plasmid DNA (pDNA-BMP2)-loaded chitosan nanoparticles (CS/CSn(pDNA-BMP2)-GP) in this study. The aim of this study was to evaluate the regenerative effect of this scaffold on the endogenous repair of alveolar bone. Thermosensitive properties, SEM scans and in vivo inflammatory reactions and degradation were evaluated. The CS/CSn-GP solution was initially injected into the muscle pouches of rats, where it changed into a gel, resulting in non-specific inflammation. It effectively enhanced new bone formation in rat calvarial defects and enhanced bony defect healing in beagle dogs. All results indicated that the CS/CSn(pDNA-BMP2)-GP complex system is a potential candidate as a targeted, multi-effect scaffold for the endogenous repair of alveolar bone. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 265-273, 2017.