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Journal of the Mechanical Behavior of... Jun 2024The mechanical properties of the jawbone play a critical role in determining the successful integration of dental prostheses. Chronic kidney disease (CKD) has been...
The mechanical properties of the jawbone play a critical role in determining the successful integration of dental prostheses. Chronic kidney disease (CKD) has been identified to abnormally accelerate bone turnover rates. However, the impact of CKD on the mechanical characteristics of the jawbone has not been extensively studied. This study sought to evaluate the time-dependent viscoelastic behaviors of rat jawbones, particularly in the scenarios both with and without CKD. We hypothesized that CKD might compromise the bone's innate toughening mechanisms, potentially owing to the time-dependent viscoelasticity of the bone matrix proteins. The maxillary and mandibular bones of Wistar rats were subjected to nanoindentation and Raman micro-spectroscopy. Load-hold-displacement curves from the cortical regions were obtained via nanoindentation and were mathematically characterized using a suitable viscoelastic constitutive model. Raman micro-spectroscopy was employed to identify nuanced vibrational changes in local molecular structures induced by CKD. The time course of indenter penetration onto cortical bones during the holding stage (creep behavior) can be mathematically represented by a series arrangement of the Kelvin-Voigt bodies. This configuration dictates the overall viscoelastic response observed during nanoindentation tests. The CKD model exhibited a reduced extent of viscoelastic contributions, especially during the initial ramp loading phase in both the maxillary and mandibular cortical bones. The generalized Kelvin-Voigt model comprises 2 K-Voigt elements that signify an immediate short retardation time (τ) and a subsequent prolonged retardation time (τ), respectively. Notably, the mandibular CKD model led to an increase in the delayed τ alongside an increase in non-enzymatic collagen cross-linking. These suggest that, over time, CKD diminishes the bone's capability for supplementary energy absorption and dimensional recovery, thus heightening their susceptibility to fractures.
Topics: Rats; Animals; Rats, Wistar; Jaw; Bone Matrix; Mandible; Renal Insufficiency, Chronic
PubMed: 38518511
DOI: 10.1016/j.jmbbm.2024.106506 -
Chinese Journal of Traumatology =... Mar 2024This study evaluated the methods and clinical effects of multidisciplinary collaborative treatment for occlusal reconstruction in patients with old jaw fractures and...
PURPOSE
This study evaluated the methods and clinical effects of multidisciplinary collaborative treatment for occlusal reconstruction in patients with old jaw fractures and dentition defects.
METHODS
Patients with old jaw fractures and dentition defects who underwent occlusal reconstruction at the Third Affiliated Hospital of Air Force Military Medical University from January 2018 to December 2022 were enrolled. Clinical treatment was classified into 3 phases. In phase I, techniques such as orthognathic surgery, microsurgery, and distraction osteogenesis were employed to reconstruct the correct three-dimensional (3D) jaw position relationship. In phase II, bone augmentation and soft tissue management techniques were utilized to address insufficient alveolar bone mass and poor gingival soft tissue conditions. In phase III, implant-supported overdentures or fixed dentures were used for occlusal reconstruction. A summary of treatment methods, clinical efficacy evaluation, comparative analysis of imageological examinations, and satisfaction questionnaire survey were utilized to evaluate the therapeutic efficacy in patients with traumatic old jaw fractures and dentition defects. All data are summarized using the arithmetic mean and standard deviation and compared using independent sample t-tests.
RESULTS
In 15 patients with old jaw fractures and dentition defects (an average age of 32 years, ranging from 18 to 53 years), there were 7 cases of malocclusion of single maxillary fracture, 6 of malocclusion of single mandible fracture, and 2 of malocclusion of both maxillary and mandible fractures. There were 5 patients with single maxillary dentition defects, 2 with single mandibular dentition defects, and 8 with both maxillary and mandibular dentition defects. To reconstruct the correct 3D jaw positional relationship, 5 patients underwent Le Fort I osteotomy of the maxilla, 3 underwent bilateral sagittal split ramus osteotomy of the mandible, 4 underwent open reduction and internal fixation for old jaw fractures, 3 underwent temporomandibular joint surgery, and 4 underwent distraction osteogenesis. All patients underwent jawbone augmentation, of whom 4 patients underwent a free composite vascularized bone flap (26.66%) and the remaining patients underwent local alveolar bone augmentation. Free gingival graft and connective tissue graft were the main methods for soft tissue augmentation (73.33%). The 15 patients received 81 implants, of whom 11 patients received implant-supported fixed dentures and 4 received implant-supported removable dentures. The survival rate of all implants was 93.82%. The final imageological examination of 15 patients confirmed that the malocclusion was corrected, and the clinical treatment ultimately achieved occlusal function reconstruction. The patient satisfaction questionnaire survey showed that they were satisfied with the efficacy, phonetics, aesthetics, and comfort after treatment.
CONCLUSION
Occlusal reconstruction of old jaw fractures and dentition defects requires a phased sequential comprehensive treatment, consisting of 3D spatial jaw correction, alveolar bone augmentation and soft tissue augmentation, and implant-supported occlusal reconstruction, achieving satisfactory clinical therapeutic efficacy.
PubMed: 38514297
DOI: 10.1016/j.cjtee.2024.03.004 -
Acta Biomaterialia Apr 2024Failure-resistant designs are particularly crucial for bones subjected to rapid loading, as is the case for the ambush-hunting northern pike (Esox lucius). These fish...
Failure-resistant designs are particularly crucial for bones subjected to rapid loading, as is the case for the ambush-hunting northern pike (Esox lucius). These fish have slim and low-density osteocyte-lacking bones. As part of the swallowing mechanism, the cleithrum bone opens and closes the jaw. The cleithrum needs sufficient strength and damage tolerance, to withstand years of repetitive rapid gape-and-suck cycles of feeding. The thin wing-shaped bone comprises anisotropic layers of mineralized collagen fibers that exhibit periodic variations in mineral density on the mm and micrometer length scales. Wavy collagen fibrils interconnect these layers yielding a highly anisotropic structure. Hydrated cleithra exhibit Young's moduli spanning 3-9 GPa where the yield stress of ∼40 MPa increases markedly to exceed ∼180 MPa upon drying. This 5x observation of increased strength corresponds to a change to brittle fracture patterns. It matches the emergence of compressive residual strains of ∼0.15% within the mineral crystals due to forces from shrinking collagen layers. Compressive stresses on the nanoscale, combined with the layered anisotropic microstructure on the mm length scale, jointly confer structural stability in the slender and lightweight bones. By employing a range of X-ray, electron and optical imaging and mechanical characterization techniques, we reveal the structure and properties that make the cleithra impressively damage resistant composites. STATEMENT OF SIGNIFICANCE: By combining structural and mechanical characterization techniques spanning the mm to the sub-nanometer length scales, this work provides insights into the structural organization and properties of a resilient bone found in pike fish. Our observations show how the anosteocytic bone within the pectoral gridle of these fish, lacking any biological (remodeling) repair mechanisms, is adapted to sustain natural repeated loading cycles of abrupt jaw-gaping and swallowing. We find residual strains within the mineral apatite nanocrystals that contribute to forming a remarkably resilient composite material. Such information gleaned from bony structures that are different from the usual bones of mammals showcases how nature incorporates smart features that induce damage tolerance in bone material, an adaptation acquired through natural evolutionary processes.
Topics: Animals; Esocidae; Bone and Bones; Stress, Mechanical; Nanoparticles; Compressive Strength; Biological Evolution; Elastic Modulus; Collagen
PubMed: 38513725
DOI: 10.1016/j.actbio.2024.03.017 -
Oral Surgery, Oral Medicine, Oral... Jun 2024
Topics: Humans; Mandibular Fractures; Middle Aged; Fractures, Spontaneous; Diagnosis, Differential; Radiography, Panoramic; Male; Tomography, X-Ray Computed
PubMed: 38508905
DOI: 10.1016/j.oooo.2024.02.014 -
Journal of Plastic, Reconstructive &... May 2024Open reduction with internal fixation is the preferred treatment option for displaced facial bone fractures. The superior mechanical properties of metallic plates have...
Evaluation of graphene oxide-doped poly-lactic-co-glycolic acid (GO-PLGA) nanofiber absorbable plates and titanium plates for bone stability and healing in mandibular corpus fractures: An experimental study.
BACKGROUND
Open reduction with internal fixation is the preferred treatment option for displaced facial bone fractures. The superior mechanical properties of metallic plates have made them the most widely used material in existing bone fixation systems. However, after the healing period, these permanent plates can cause various problems. Alternative bioresorbable materials are being investigated to reduce these potential problems. This study compares bone stability and viability by using graphene oxide (GO)-doped poly-lactic-co-glycolic acid (PLGA) nanofiber plates and titanium plates for rats with fractured mandibles.
MATERIALS AND METHODS
The study included 20 male Sprague-Dawley rats, divided into four groups: a control group (Group I), a mandibular fracture group with no additional application (Group II), a mandibular fracture group repaired with titanium plates (Group III), and a mandibular fracture group repaired with GO-PLGA plates (Group IV). After 2 months, all of the rats were euthanized. A bone compression test was performed to assess bone stability, and a histological examination was performed to evaluate bone healing.
RESULTS
The osteocyte lacunae, Haversian ducts, canaliculi, and vascular structures of Group IV were found to be higher. In the compression test, vertical compression was applied to the bone axis, and Group IV had a higher maximum load and maximum stretch. GO-PLGA plates were found to be statistically superior to titanium plates in terms of both bone stability and bone healing (p < 0.05).
CONCLUSIONS
The present study found that GO-PLGA plates are more effective than titanium plates for the treatment of mandibular corpus fractures.
Topics: Animals; Rats, Sprague-Dawley; Titanium; Polylactic Acid-Polyglycolic Acid Copolymer; Male; Graphite; Bone Plates; Rats; Mandibular Fractures; Nanofibers; Fracture Fixation, Internal; Absorbable Implants; Fracture Healing
PubMed: 38507862
DOI: 10.1016/j.bjps.2024.02.063 -
The Journal of Craniofacial Surgery Jun 2024An improved method of treating inwardly dislocated mandibular extracapsular condylar fracture-three times titanium plate gradual fixation method was introduced, and the...
OBJECTIVE
An improved method of treating inwardly dislocated mandibular extracapsular condylar fracture-three times titanium plate gradual fixation method was introduced, and the clinical efficacy of this method was evaluated.
METHODS
Twenty patients with extracapsular condylar fractures who underwent surgical treatment using the three times titanium plate gradual restoration and fixation method in the Department of Oral Craniomaxillofacial Surgery of the Ninth People's Hospital of Shanghai from November 2020 to June 2023 were selected as the study subjects.
RESULTS
After condylar restoration 22 sides reached healing and 1 side was basically healed; in 3 months after the operation, the degree of opening the mouth and the type of the opening of the mouth reached normal, and 1 case had mildly poor occlusion, which required to be further adjusted through orthodontics, and there was no temporomandibular function disorder or facial nerve function damage.
CONCLUSION
Three times of gradual fixation with a titanium plate can make the condylar process achieve precise and stable repositioning, and make the surgical process orderly, and it is a kind of reliable fixation method for extracapsular condylar fractures.
Topics: Humans; Mandibular Fractures; Bone Plates; Titanium; Mandibular Condyle; Male; Fracture Fixation, Internal; Female; Adult; Middle Aged; Treatment Outcome; Young Adult; Adolescent
PubMed: 38483294
DOI: 10.1097/SCS.0000000000010005 -
Journal of Cranio-maxillo-facial... Apr 2024This study aimed to evaluate the feasibility and accuracy of a combined virtual surgical planning (VPS) and short-segment drilling guides (SSDGs) workflow for the...
This study aimed to evaluate the feasibility and accuracy of a combined virtual surgical planning (VPS) and short-segment drilling guides (SSDGs) workflow for the treatment of complex mandibular fractures. Consecutive patients with complex mandibular fractures underwent treatment using the VPS and SSDGs workflow from August 2020 to April 2022. Various mandibular landmarks were compared between the preoperative virtual surgical plan and postoperative data, including condylar distance (CoD), mandibular angle width (GoL-GoR), GoMeGo angle (∠GoL-Me-GoR), the difference in mandibular angles between the left and right sides (Δ∠Co-Go-Me), and the difference in length between the left and right mandibular body (ΔGo-Me). Additionally, preoperative preparation time and surgical duration were retrospectively analyzed and compared to conventional surgery. All 14 consecutive patients with complex mandibular fractures achieved successful reduction using the VPS and SSDGs workflow. Three-dimensional comparison revealed a mean deviation distance of 0.91 ± 0.50 mm and a root-mean-square deviation of 1.75 ± 0.47 mm between the preoperative designed mandible model and the postoperative mandible model. The percentage of points with deviation distances less than 2 mm, 1 mm, and 0.5 mm between preoperative and postoperative models were 78.47 ± 8.87 %, 60.02 ± 14.28 %, and 38.64 ± 15.48 %, respectively. There were no significant differences observed in CoD, GoL-GoR, ∠GoL-Me-GoR, Δ∠Co-Go-Me, and ΔGo-Me between preoperative virtual surgical planning and postoperative measurements. Furthermore, no significant differences were found in the injury-to-surgery interval, admission-to-surgery interval, and surgical duration between the workflow and conventional surgery. The combined VPS and SSDGs workflow proved to be an accurate and feasible method for treating complex mandibular fractures. It offers advantages such as minimal preoperative preparation time and the ability to precise transfer screw positions of the pre-bent reconstruction plate during surgery. This approach is particularly suitable for managing complex mandibular fractures.
Topics: Humans; Mandibular Fractures; Retrospective Studies; Tomography, X-Ray Computed; Surgery, Computer-Assisted; Mandible; Mandibular Reconstruction
PubMed: 38458893
DOI: 10.1016/j.jcms.2023.11.009 -
The Lancet. Diabetes & Endocrinology Apr 2024We previously identified that zoledronate administered at 18-month intervals reduced fragility fractures by a third in a 6-year trial of women older than 65 years with... (Randomized Controlled Trial)
Randomized Controlled Trial Observational Study
BACKGROUND
We previously identified that zoledronate administered at 18-month intervals reduced fragility fractures by a third in a 6-year trial of women older than 65 years with osteopenia. This extension aims to identify the persistence of these effects.
METHODS
Of the 2000 ambulant, community dwelling, postmenopausal women older than 65 years recruited in Auckland, New Zealand, with T-scores at the total hip or femoral neck in the range -1·0 to -2·5, we invited participants who received four doses of intravenous zoledronate, completed follow-up to year 6 of the core trial, did not have metabolic bone disease (other than osteoporosis), and were not using bone-active drugs into this 4-year observational study extension, during which further treatment was at the discretion of their own doctors. Participants were asked to notify study staff of any new fractures and were telephoned at 7·5 years and 9·0 years to update their health status. Participants were then invited to an onsite visit at 10·0 years. Fractures and other health events were documented at each contact and analysed in all women who entered the extension, and bone mineral density (BMD; analysed in participants without notable use of bone-active medications who attended an onsite visit at 10 years) and turnover markers (measured from fasting morning blood in a random subset of 50 participants) were measured at year 10.
FINDINGS
Of the 1000 women randomly assigned to receive zoledronate in the core trial, 796 participants were eligible for the extension, of whom 762 (96%) entered the extension between Sept 24, 2015, and Dec 13, 2017. Mean follow-up duration was 4·24 years (SD 0·57, range 0·61-6·55; final follow-up on May 25, 2022). 727 (91%) of participants were assessed at 10 years. 25 women died during the extension, six withdrew for medical reasons, and four were lost to follow-up. 92 women suffered 114 non-vertebral fractures during the extension. Non-vertebral fracture rates increased from a nadir of 15 fractures per 1000 woman-years (95% CI 10-21) in the last 2 years of the core trial to 24 fractures (17-33) in years 6-8 and 42 fractures (32-53) in years 8-10, similar to that in the placebo group in the last 2 years of the core trial. Total hip BMD (relative risk per 0·1 g/cm 0·73, 95% CI 0·57-0·93; p=0·011) and a previous history of non-vertebral fracture (1·74, 1·12-2·69; p=0·013) at year 6 predicted incident fractures but change in total hip BMD did not. Total hip BMD decreased from 4·2% above study baseline to 0·8% above baseline (p<0·0001) during the extension. Turnover markers were not useful for predicting BMD loss in individuals. Osteonecrosis of the jaw or atypical femoral fractures did not occur in any participants.
INTERPRETATION
The reduced fracture rates following zoledronate in the core trial were substantially maintained for 1·5-3·5 years after the last zoledronate infusion, but not thereafter.
FUNDING
Health Research Council of New Zealand.
Topics: Female; Humans; Zoledronic Acid; Bone Density Conservation Agents; Follow-Up Studies; Fractures, Bone; Bone Diseases, Metabolic; Bone Density; Osteoporosis, Postmenopausal
PubMed: 38452783
DOI: 10.1016/S2213-8587(24)00003-2 -
Journal of Cranio-maxillo-facial... May 2024Our study aimed to evaluate modified patient-specific surgical-guide-assisted precise treatment of unilateral comminuted zygomaticomaxillary complex (ZMC) fractures. The...
Our study aimed to evaluate modified patient-specific surgical-guide-assisted precise treatment of unilateral comminuted zygomaticomaxillary complex (ZMC) fractures. The retrospective non-randomized study was conducted in a single hospital in China. All patients diagnosed with unilateral comminuted ZMC fractures between January 1, 2018 and December 31, 2022 were retrospectively reviewed. All patients underwent preoperative spiral computed tomography (CT). CT data were processed using software to DICOM format and transferred to Proplan CMF3.0 for preoperative virtual surgical planning and postoperative evaluation. All data were extracted from standardized electronic medical records. All statistical analyses were performed using SPSS version 20.0. The chi-square test and t-test were used for statistical analyses. The 54 included patients were divided into two comparable, equal cohorts of 27 patients, and followed up for at least 6 months. Fracture reduction was assisted using the modified patient-specific surgical guides in the guide group (23 males, four females; mean age 37.74 ± 12.07 years) and without the modified patient-specific surgical guides in the control group (20 males, seven females; mean age 37.44 ± 13.58 years). In the guide group, the mean eminence deviation between the affected and unaffected sides was 1.01 ± 0.92 mm, and the mean width deviation between the affected and unaffected sides was 1.29 ± 1.32 mm. In the control group, the mean eminence deviation between the affected and unaffected sides was 1.99 ± 1.69 mm, and the mean width deviation between the affected and unaffected sides was 2.68 ± 2.01 mm. The differences in facial protrusion (p = 0.001) and width (p = 0.003) symmetry between the affected and healthy sides of the two groups were statistically significant (p < 0.05). In conclusion, applying the modified patient-specific surgical guides to unilateral comminuted zygomaticomaxillary complex fracture reduction has the advantages of greater predictability and effectiveness, and improved bilateral ZMC symmetry. It should be noted that this approach would be especially beneficial for less-experienced surgeons.
Topics: Humans; Retrospective Studies; Male; Female; Zygomatic Fractures; Adult; Fractures, Comminuted; Maxillary Fractures; Middle Aged; Surgery, Computer-Assisted; Tomography, Spiral Computed; Imaging, Three-Dimensional; Fracture Fixation, Internal
PubMed: 38448338
DOI: 10.1016/j.jcms.2024.02.021