A 3D micro-computed tomography study comparing embryonic skeletal development in layer versus broiler strains of the domestic chicken.

Our objective was to analyze the effect of selection for divergent traits in the domestic chicken on embryonic skeletal development, which could affect postnatal bird welfare. Development was compared between the Ross 308 broiler line (fast growth and muscle mass accrual) and Novoponte layers (high laying rate and egg quality). In Study 1 (Initial Conditions), we characterized egg composition prior to incubation and identified the onset of embryonic skeletal mineralization in the 2 strains. In Study 2 (Developmental Dynamics), we used 3D X-ray tomographic imaging (µCT) on incubation days ED11, ED13, ED15 and ED17 to track skeletal maturation trajectories as a pseudo-time series. Results showed that Ross 308 embryos, which are heavier than Novoponte embryos, possess higher levels of yolk nutrients including phosphorus and calcium, but lower eggshell mineral content, than Novoponte embryos. Skeletal mineralization started synchronously in both strains, on ED11. The higher mineral ion content in the larger yolk of Ross 308 eggs compared to Novoponte eggs may partly explain why skeletal mineralization in Ross 308 embryos advances faster: using µCT, we show that the mandible and tibiotarsi in Ross 308 embryos are larger at ED11 and ED13 compared with Novoponte embryos. However, Novoponte embryos catch up from this initial lag in mineralization by ED15. The timing of the Novoponte acceleration coincides with the functional activation of the chorioallantoic membrane in releasing calcium from the inner eggshell. This correlates with a decrease in eggshell thickness from ED11 to ED17 in Novoponte eggs, which was not observed during Ross 308 incubation. To conclude, while some temporal discrepancies exist in early skeletal development between the embryos of Ross 308 and Novoponte strains, overall prenatal skeletal maturation seems to be robustly regulated. Despite selection for antagonist production traits, layer and broiler prehatch skeletal morphology ultimately synchronizes. Practically, since the extent of skeletal maturity equalizes between strains towards the end of incubation, refinements of farming practices, postnatal environment, and diet should be considered for improving domestic fowl welfare.

Analysis of osseointegration of implants with macrogeometries with healing chambers: a randomized clinical trial.

BACKGROUND: To verify the influence of macrogeometry with healing chambers on the osseointegration of dental implants by analyzing implant stability quotient (ISQ) and evaluate the correlation between insertion torque and ISQ insertion with different macrogeometries. METHODS: In total, 26 implants were installed in the posterior mandible of eight patients with sufficient bone height for the installation of implants measuring 3.5 mm in diameter and 9.0 mm in length. The implants were categorized according to two types of macrogeometry: a test group (GT) with 13 conical implants with healing chambers and a control group (GC) with 13 conical implants with conventional threads. To insert the implants, a bone drilling protocol was used up to a diameter of 3 mm with the last helical bur. The insertion torque of the implants was evaluated, followed by the measurement of ISQ at 0 (T-0), 7 (T-7), 14 (T-14), 21 (T-21), 28 (T-28), and 42 (T-42) days. RESULTS: The mean insertion torque was 43 Ncm in both groups, without a significant difference. Moreover, no significant difference in the ISQ values was found between the groups at different time points (p > 0.05), except at T-7 (GT = 69.87±1.89 and GC = 66.48±4.49; p = 0.01). Although there was no significant difference, ISQ median values were higher in the GT group than GC group at 28 days (GT = 67.98 and GC = 63.46; p = 0.05) and 42 days (GT = 66.12 and GC = 60.33; p = 0.09). No correlation was found between the insertion torque and ISQ insertion (p > 0.05). CONCLUSION: Furthermore, implants with a 3.5 mm diameter macrogeometry, with or without healing chambers, inserted with a drilling protocol up to 3 mm in diameter of the last helical bur, led to a similar secondary stability, with no difference in ISQ values. Although, implants with healing chamber demonstrates ascending values in the graph of ISQ, having a trend of faster osseointegration than implants without healing chambers. Both macrogeometries provide a similar primary stability to implants. TRIAL REGISTRATION: This study was registered retrospectively in ReBec (brazilian registry of clinical trials) under the number RBR-96n5×69, on the date of 19/06/2023.

Evaluation of complications in patients with mandible fractures undergoing chronic kidney disease in the United States.

BACKGROUND: This research aims to assess the demographic characteristics, prevalence, outcomes, and complications in chronic kidney disease (CKD) patients following mandible fractures in the United States using a nationally representative database. METHODS: We analyzed data from the National Inpatient Sample from 2010 to 2019 in the United States. Patients with mandible fractures were categorized into three groups based on the International Classification of Diseases, Ninth and Tenth Revisions (ICD-9-CM and ICD-10-CM): end-stage renal disease (ESRD), non-ESRD CKD, and healthy kidney function. Chi-squared tests and analysis of variance (ANOVA) were used to compare these groups. Additionally, multivariate regression analysis was performed to determine whether CKD is an independent risk factor for complications in patients with mandible fractures. RESULTS: A total of 38,481 patients in the United States were estimated to have experienced mandible fractures between 2010 and 2019. The incidence rate of non-ESRD CKD in patients with mandible fractures significantly increased over time, while the prevalence of ESRD remained stable during the ten-year period. Compared to the healthy kidney function group, patients with chronic kidney disease exhibited higher hospital costs, longer hospitalization durations, and higher in-hospital mortality rates. Additionally, they had greater odds ratios for most of the investigated complications. CONCLUSIONS: This study revealed a steady annual increase in the morbidity rate of non-ESRD CKD among patients with mandible fractures, while ESRD prevalence remained stable over ten years. We observed a close association between chronic kidney disease and the prognosis of patients with mandible fractures. Clinicians should prioritize preventive measures and appropriate management of mandibular fractures in patients with CKD.

Application of bone perforation in the surgery of medication-related osteonecrosis of the jaw in stage â ¡.

OBJECTIVES: This study aimed to explore the effect of surgery combined with bone perforation for treating stage Ⅱ medication-related osteonecrosis of the jaw (MRONJ). METHODS: A total of 21 patients with stage Ⅱ mandibular MRONJ who underwent surgical treatment from June 2020 to June 2023 were included in this study. Retrospective analysis was conducted on their clinical data, including gender, age, primary disease, drug name and administration method, pre-surgery drug cessation, and prognosis. The cohort comprised 14 males and 7 females, with an average age at onset of 68.33±10.74 years. According to the guidelines of the American Association of Oral and Maxillofacial Surgeons, the included patients had stage Ⅱ mandibular MRONJ. The treatment approach consisted of partial mandibulectomy combined with bone perforation techniques, ensuring tension-free suturing of soft tissues. Follow-up was performed regularly, and the curative effect was evaluated. The SF-12 health survey was used to assess the quality of life for all patients before and after surgery. RESULTS: A total of 21 patients were followed up for 8-38 months after surgery, and the mucosal healing of 17 patients was good (80.95%). The postoperative quality of life score (83.62±5.90) was significantly higher than that before operation (63.67±4.70, P<0.05). CONCLUSIONS: Surgery combined with bone perforation te-chnique is an effective treatment method with high success rate in refractory stage Ⅱ MRONT patients.

Axial split step osteotomy of free iliac crest flaps for mandible reconstruction: Preliminary results.

BACKGROUND: Vascularized bone grafting (VBG) is preferred for mandibular reconstruction post-tumor ablation. Although various bone-free flaps are used, their application is compromised by limitations including insufficient bone volume and poor shape. Here, we report mandibular reconstruction using axial split-step osteotomy with an iliac crest-free flap. METHODS: Over December 2018-November 2020, 12 patients underwent mandibular reconstruction via axial split osteotomy using a free iliac-crest flap. RESULTS: The preoperative iliac-crest length was 5.7-9.5 mm (median, 7.5 cm); the mean post-axial split-osteotomy iliac-crest length increased to 9.59 mm (range, 6.34-15.15 mm). All patients presented with initial healing 2 weeks postoperation; good bone healing was achieved in all grafted flaps by the third month of follow-up. CONCLUSIONS: We propose a new axial split-step osteotomy technique using free iliac-crest flaps for mandibular reconstruction. We demonstrated this novel technique's reliability for safe and effective bone lengthening and establishing a reliable occlusal relationship.

Mandible-First and Maxilla-First Sequencing in Virtual Surgical Planning for Orthognathic Surgery: Comparison of Planned and Actual Outcomes.

Background: Recent studies have shown that virtual planning for orthognathic surgery is an accurate and repeatable method. It is also a fact that surgical sequence can affect the results in terms of accuracy. Various studies stated that both approaches offer comparable results when properly planned and implemented; however, further clinical studies are still needed. This study aims to evaluate the effect of virtual surgical planning (VSP) on surgical outcomes and whether it is affected by mandible-first or maxilla-first approaches. Methods: This study analyzed data from 45 patients who underwent orthognathic surgery due to dentofacial deformity. Six of these patients underwent single-jaw orthognathic surgery, and 39 underwent bimaxillary orthognathic surgery (Maxilla-first group: 21, mandible-first group: 18). The displacements of specific landmarks were assessed by comparing preoperative and postoperative conventional computed tomographies with VSP data. Results: This study showed a statistically significant relationship between the measurements made with the 2 methods (r = .944; P = .0001). The fact that the intra-class correlation coefficient value is statistically significant and relatively high and that most of the differences in the Bland-Altman chart fall between the limits of compliance indicates a correlation between the virtual plan and surgical outcomes. In addition, in vertical measurements, the absolute mean difference of the B point and the Pogonion in the Maxilla-first group were statistically significantly higher than in the Mandible-first group (P = .038, P = .011). Conclusions: Our findings corroborate the high accuracy of the VSP reported in previous studies and also demonstrate that VSP with both maxilla-first and mandible-first sequencing achieves high accuracy in the sagittal and coronal planes. Although virtual planning significantly influences accurate surgical outcomes, it is not the sole determinant. Factors like condylar positioning and fixation methods can also impact the final results.

Comparison of Mineral Density of Dental Structures of Ancient Human Skeletons from the Roman Period with Modern-Day Human Dental Structures.

OBJECTIVES: Comparison of maxillary, mandibular, dental crown and root mineral density in human skeletons identified in historical excavations with today's human maxillary, mandibular dental crown and root. METHODS: After the skull images were obtained, four groups were created: maxilla 1, mandible 1 from the old period, maxilla 2 from the images taken from today's patients, and mandible 2 from the images taken from today's patients. Seventeen skeletons were previously classified as young age, middle age, and older age. Among the archive tomography images, 17 images from young (15-35), middle (36-56) and older (57 and over) age images were included in the study. HU value of the desired region was calculated automatically by the device using Region of interest (ROI). RESULTS: In this study, 34 jaws and 68 teeth were evaluated, including 7 mandibles and 10 maxillae from the late Roman period, and 8 mandibles and 9 maxillae from today's people. The average HU value of the crowns of mandibular anterior teeth from the late Roman period was measured as 2406.0. The average HU value of the crowns of maxillary anterior teeth was found to be 3383.8. In the posterior aspect, the average crown HU value measured in the maxilla was found to be higher than that in the mandible. CONCLUSIONS: The finding showed that the density of dental tissues of ancient people, such as enamel and dentin forming the crown, and cementum and dentin forming the root, was significantly higher than today's people.

Osteosynthesis for mandibular reconstruction with fibula free flap: Which type and why? A French national survey.

We explored the most suitable osteosynthesis type for mandibular reconstruction using fibula free flap (FFF) given the lack of robust data available. For this, an anonymous survey was e-mailed to 853 head-and-neck surgeons (France) asking about their practices and criteria guiding their osteosynthesis material and method choices. Questions assessed: (1) the most frequently used osteosynthesis type, (2) the explanatory variables related to surgeon career status/surgical specialty, and (3) justifications for osteosynthesis type (scientific, technical, "misuse"). Multivariate logistic regression was performed to test for associations of explanatory variables with plate type or misuse. Overall, 118 (13.8%) surgeons responded, among which flexible non-locking osteosynthesis was preferred (59%). Career status and surgical specialty were significantly associated with material choice. University professors/senior lecturers (OR 5.96 vs academic clinical associates; p = 0.02), but not ear-nose-throat/reconstructive plastic surgeons (OR 0.22 vs maxillofacial surgeons; p = 0.04), were more likely to opt for rigid locking osteosynthesis. Private practitioners preferred flexible non-locking osteosynthesis (OR = 5.03; p = 0.04). Only 18% of surgeons scientifically justified their choices. We considered misuse among 65% of surgeons and this was significantly associated with irregular practice of FFF surgery (OR 2.28 vs > 10 surgeries/year; p = 0.04). Overall, >50% of surgeons mainly rely on habits without scientific arguments assisting in decision-making.

Association between mandibular prognathism and Matrilin-1, bone morphogenic protein, Tyr67Asn, homeobox protein hox-A2, Rho-GTPase activating protein, and Myosin 1H genes in the Indian population.

INTRODUCTION: Mandibular prognathism (MP) patients present with aesthetic concerns and functional issues, including difficulties in mastication and pronunciation. Studies revealed that mandibular prognathism had definitive Mendelian inheritance patterns. This study aimed to ascertain distinct genetic markers associated with mandibular prognathism in individuals of Indian descent, focusing on exploring the prevalent genetic variations associated with certain genes. This study sought to identify the association of the following gene markers with mandibular prognathism: 1) Matrilin-1 (MATN1) (rs1065755), 2) Bone morphogenic protein 3 (BMP-3) (Tyr67Asn), 3) Homeobox protein hox-A2 (HOXA2) (Val327Ile), 4) Rho-GTPase activating protein (ARHGAP 21) (Gly1121Ser), 5) Myosin 1H (MYO1H) (rs10850110).

Changes of masseter muscle after mandible distraction osteogenesis in patients with Hemifacial microsomia: a retrospective study.

Introduction: Mandible distraction osteogenesis (MDO) is widely used to reconstruct the mandible in patients with mild Hemifacial microsomia (HFM). However, the masseter's response to mandible distraction remains unclear. Methods: In this study, we analyze the effect of the surgical intervention on masseter muscle by a retrospective analysis. The procedure consisted of a five-day latent period, a three-week distraction period, and a six-month consolidation period. CT data were manually segmented and measured with Mimics software before surgery, within 3 months, and more than 1 year postoperatively. Masseter volume, masseter length, masseter width, and mandible ramus height were measured and analyzed using paired t-test, Pearson, and Spearman correlation analysis. Results: We included 21 patients with HFM who underwent mandible distraction osteogenesis from 2015 to 2020. The masseter volume on the affected side increased immediately after surgery from (6,505.33 ± 3,671.95) mm3 to (10,194.60 ± 5638.79) mm3, but decreased to (8,148.38 ± 3,472.57) mm3 at the second follow-up correlated to mandible ramus height (r = 0.395, P = 0.038). A similar trend was observed in changes in masseter length. Symmetry and width of masseter muscle had no longitudinal statistical significance. Discussion: Masseter muscle involvement benefits from MDO in the short term. To achieve long-term efficacy, more attention should be paid to muscle reconstruction.

Outcomes of non-surgical management of non-condylar mandibular fractures: a systematic review and meta-analysis.

Surgical intervention utilising open and (less commonly) closed reduction, are the main methods for the management of fractures of the mandible that do not involve the condyle or coronoid. Non-surgical management of these fracture patterns is rare. This systematic review aimed to collate current evidence surrounding this topic. A systematic review was undertaken using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria were adults with mandibular fractures. Exclusion criteria included any form of surgical intervention including open or closed reduction, and fractures of the condyle or coronoid. Four studies satisfied the eligibility criteria and comprised 80 patients. A total of 69 patients (86%) who were managed non-surgically produced satisfactory clinical outcomes with no surgical intervention required. The evidence suggests that non-surgical management can successfully avoid surgery in most cases when certain criteria are applied. This has huge health economic implications as it reduces morbidity and requirements for theatre and inpatient stay. Further research is required to establish which fracture patterns are most amenable to this approach, the most effective non-surgical instructions, and the recommended follow-up period.

A Case of an Ossifying Fibroma of the Mandible Suspected as a Static Bone Cavity.

Ossifying fibroma (OF) is a benign fibro-osseous lesion characterized by the proliferation of fibrous connective tissue containing immature bone and/or cementum-like hard tissue. Although the pathogenesis of OF remains unclear, trauma, previous extractions, and periodontitis are considered potential trigger factors. OF is more common in women aged from the second to fourth decades. Clinically, OF is characterized by slow-growing and asymptomatic swelling, often observed incidentally on radiological examinations. OF occurs more frequently in the mandible, particularly above the mandibular canal. Herein, we present a rare case of OF in an 18-year-old man initially misdiagnosed as a static bone cavity. The lesion was first observed as a radiolucent finding below the left mandibular canal on a panoramic radiograph. Later, cone-beam computed tomography (CBCT) imaging revealed the presence of calcifications within the lesion. Additionally, CBCT confirmed the presence of the lesion within the lingual cortical bone, revealing lingual swelling and thinning of the outer cortex. Enucleation was successfully performed under general anesthesia without any postoperative complications. Histopathological examination confirmed the diagnosis of OF, revealing mineralized tissue and proliferating fibrous connective tissue. This case underscores the challenges in diagnosing OF, particularly when it is located below the mandibular canal, emphasizing the importance of thorough imaging and differential diagnosis to avoid misinterpretation as a static bone cavity.

Prevalence of accessory mental foramen and lateral lingual foramen using cone beam computed tomography: A single-center cross-sectional study.

PURPOSE: This study aimed to assess the prevalence, dimensions, and positions of accessory mental foramen (AMF) and lateral lingual foramen (LLF) in an Iranian population using cone beam computed tomography (CBCT). METHODS AND MATERIALS: In this cross-sectional study, CBCT images of 2082 patients were retrospectively reviewed based on inclusion criteria, including images from the mandibular region taken in the past five years with accurate demographic data. Exclusion criteria included images with significant pathologies, fractures, or poor quality. CBCT images were captured, and AMF and LLF presence (primary outcome variable), dimensions, and positions (secondary outcome variables) were recorded relative to the mental foramen and adjacent teeth. Data analysis was performed using the Chi-square test with a 5% significance level. RESULTS: A total of 2082 CBCT samples (46.54% females and 53.46% males) with a mean age of 48.30 ± 12.70 years were examined. Among these, 246 AMFs were observed in 222 individuals with a prevalence at the foramen level of 11.815%, with 24 having two AMFs. AMF was mostly observed unilaterally, with bilateral occurrence noted in 10.81% of patients with AMF. Additionally, 86 patients were found to have LLF with a prevalence at the foramen level of 5.907%. There were no significant differences between genders in AMF and LLF prevalence. CONCLUSION: AMF and LLF were detectable using CBCT in the selected Iranian population. AMF was commonly situated posterior and superior to the mental foramen, while LLF was often found near the first premolar. This knowledge is crucial for preventing nerve injury during surgery and ensuring effective nerve block procedures.

Diffuse Large B-Cell Lymphoma in a Cynomolgus Monkey.

A captive 17-year-old male cynomolgus monkey (Macaca fascicularis) developed diffuse large B-cell lymphoma (DLBCL). This was the first report of DLBCL presenting with a mandible mass and violation of the paranasal sinus in a cynomolgus monkey. The neoplasm showed marked microscopical malignant aspects. Immunohistochemical staining showed strong positive expression of CD20. These features may contribute to the diagnosis and therapeutics of DLBCL in NHPs.

Does crown-to-implant ratio affect marginal bone loss around a single short implant at the posterior of the mandible?

Context: Short implants are acceptable treatment options for atrophic ridges; however, they increase the crown-to-implant (C/I) ratio compared to regular length implants. The study aimed to assess the correlation between the C/I ratio and marginal bone loss (MBL) in single short implants at the posterior of the mandible. Aims: The study aimed to assess the correlation between the C/I ratio and MBL in single short implants at the posterior of the mandible. Settings and Design: Cross-sectional study. Materials and Methods: This cross-sectional study assessed short implants with 6 mm lengths at the posterior of the mandible. The long-cone peri-apical digital radiographs were taken immediately after loading and 24 months later. Age, gender, implant diameter, gingival biotype, and implant brands were the study variables, and the C/I ratio was the predictive factor. The mean MBL at 2 years was considered the study outcome. Statistical Analysis Used: The Pearson correlation test was applied to assess the correlation between MBL and C/I. Results: Seventy implants (36 Straumann and 34 SGS implants) were studied. A significant difference was observed in the mean MBL between the two implant brands (P < 0.001). Besides, a correlation was found between MBL and the C/I ratio (P = 0.002). Conclusions: It seems that the C/I ratio is associated with an MBL increase in single short implants at the posterior of the mandible.

Does mandible ramus height asymmetry affect postoperative skeletal stability in orthognathic surgery patients?

BACKGROUND: Relapses following orthognathic surgery have been reported to exceed 2% to 50%, depending on multiple factors. This study aimed to analyze the stability after orthognathic surgery in patients with mandibular ramus height asymmetry through 3D reconstruction using Cone-beam CT. METHODS: This retrospective cohort study investigated patients who underwent mandibular setback surgery using bilateral sagittal split ramus osteotomy. Three-dimensional CT scans were taken at three different time points. Evaluation of the postoperative stability involved measuring changes in the x, y, and z axes as well as roll and yaw rotations of the mandible at specific landmarks (B point, mental foramen) on 3D CT scans obtained immediately after surgery and 6-12 months postoperatively. They were categorized into four groups based on bilateral mandibular height asymmetry through Asymmetry index (AI). The one-way ANOVA was implemented to compare the intergroup differences and Tukey's post hoc test was employed. Additionally, the Pearson correlation coefficient was also calculated. RESULTS: A total of 24 patients were included in this study. The corresponding AI, representing the degree of asymmetry in both mandibles, were calculated as Group 1 was 1.25 ± 0.64%, Group 2 was 2.89 ± 0.47%, Group 3 was 5.03 ± 0.51%, and Group 4 was 9.40 ± 1.99%. The x-axis change in Group 4 was significantly larger at 1.71 mm compared to Group 1 at 0.64 mm. The mandibular roll, Group 4 showed a statistically significant increase at 1.33° compared to Group 1 at 0.35°. And there was a significant positive correlation observed between x-axis change and AI (p = 0.019), as well as between mandibular roll and AI (p = 0.025). CONCLUSION: After orthognathic surgery, stability was influenced by numerous factors, with the findings of this study suggesting that the degree of ramus height asymmetry in the mandible can be considered one contributing factor.

The Biocompatibility and the Effect of Titanium and PEKK on the Osseointegration of Customized Facial Implants.

The purpose of this study was to investigate the optimization of computer-aided design/computer-aided manufacturing (CAD/CAM) patient-specific implants for mandibular facial bone defects and compare the biocompatibility and osseointegration of machined titanium (Ma), Sandblasted/Large-grit/Acid-etched (SLA) titanium, and polyetherketoneketone (PEKK) facial implants. We hypothesized that the facial implants made of SLA titanium had superior osseointegration when applied to the gonial angle defect and prevented the senile atrophy of the bone. Histologic findings of the soft-tissue reaction, hard-tissue reaction, and bone-implant contact (BIC (%) of 24 Ma, SLA, and PEKK facial implants at 8 and 12 weeks were investigated. There was no statistical difference in the soft tissue reaction. Bone was formed below the periosteum in all facial implants at 12 weeks and the BIC values were significantly different at both 8 and 12 weeks (p < 0.05). Ma, SLA, and PEKK facial implants are biocompatible with osseointegration properties. SLA can enhance osseointegration and provoke minimal soft tissue reactions, making them the most suitable choice. They provide an excellent environment for bone regeneration and, over the long term, may prevent atrophy caused by an aging mandible. The bone formation between the lateral surface of the facial implant and periosteum may assist in osseointegration and stabilization.

Finite Element Assessment of a Novel Patient-Specific Mandibular Implant for Severely Atrophic Ridge.

Purpose: Dental reconstruction for patients diagnosed with severe mandibular bone atrophy using common dental implants is a challenging process. In such cases, surgeons may encounter challenges such as insufficient available bone, soft tissue, damage to the inferior alveolar nerve, and even the risk of bone fracture. In this study, a new design concept of mandibular patient-specific implants for severely atrophic ridges followed by finite element evaluation was presented to investigate the mechanical functionality of the concept. Method: The implant is comprised of two modular parts including an inferior border cover and a horseshoe-shaped structure. This horseshoe segment fits into the cover and is then screwed to it using two screws on each side. A 1 mm deflection was applied to a reference point located between the two anterior posts to extract the resulting Von Mises stress distribution in each part and the reaction force on the reference point which corresponds to the chewing force that the patient must apply to deform the horseshoe. This 1 mm gap is a design consideration and critical distance that horseshoe contacts the gingiva and disturbs the alveolar nerve. Results: The results revealed that load was transmitted from the horseshoe to the cover, and there were no stress contours on the body of the mandible. However, stress concentration was observed in screw locations in the mandible, the amount of which was decreased by increasing the number of used screws. In horseshoe, stress concentration values were around 350 MPa, and the measured reaction force on the reference point was just under 200 N. Conclusion: The finite element analysis results showed that this concept would be functional as the minimum load would be transmitted to the mandibular ridge, and since the patients diagnosed with atrophic ridge are not able to apply load to an amount near 200 N, the horseshoe would not contact the gingiva. Also, it is concluded that increasing the number of bone screw fixations would decrease the risk of long-term screw loosening.

Imaging approach for jaw and maxillofacial bone tumors with updates from the 2022 World Health Organization classification.

Jaw and maxillofacial bone lesions encompass a wide variety of both neoplastic and non-neoplastic pathologies. These lesions can arise from various tissues, including bone, cartilage, and soft tissue, each presenting distinct challenges in diagnosis and treatment. While some pathologies exhibit characteristic imaging features that aid in diagnosis, many others are nonspecific. This overlap often necessitates a multimodal imaging approach, combining techniques such as radiographs, computed tomography, and magnetic resonance imaging to achieve a diagnosis or narrow the diagnostic considerations. This article provides a comprehensive review of the imaging approach to jaw and maxillofacial bone tumors, including updates on the 2022 World Health Organization classification of these tumors. The relevant anatomy of the jaw and dental structures that is important for accurate imaging interpretation is discussed.

Osteosarcoma of Mandible - A Case Report.

After plasma cell neoplasia, osteosarcoma is the most common primary bone tumor which accounts for 20% of all sarcomas. A malignant tumor is characterized by the formation of bone or osteoid by tumor cells. Long bones are the most common site of involvement. In the jaw bones, approximately 5% of involvement with an incidence of 1 in 1.5 million persons per year. It develops in a broad range of ages but is more common in the third and fourth decades, slightly more often in the mandible than in the maxilla. In this case report, a 24-year-old male patient reported a mass in the left mandible for the past 1 week which appeared after the third molar extraction. In the orthopantomogram, a loss of lamina dura and a change in the trabecular pattern was noted. Histopathological findings were suggestive of osteoblastic osteogenic sarcoma. The patient underwent a hemi-mandibulectomy followed by chemotherapy. The main aim of this case report was to focus on the importance of early diagnosis of this tumor based on clinical and radiographic examinations, particularly taking into account the fast progression and aggressiveness of this neoplasm.