Jaw Bone Research Articles

Comparison of stress distribution in fully porous and dense-core porous scaffolds in dental implantation

The aim of this study is to compare the stress distribution in porous scaffolds with different structures with similar geometric parameters to study a new approach in dental implantation. Three-dimensional finite element models of the fully porous and dense-core porous scaffolds with defined porosity parameters including space diameter and thickness with two porosity patterns were embedded in the jaw bone model with cortical and cancellous bone. The cylindrical shape was considered as the main shape of the scaffolds. To evaluate the mechanical performance, the Von Mises stress was compared in the models under static and dynamic masticatory loading. Incidentally, to validate the modeling results, experimental strain gauge tests were performed on four specimens fabricated from Ti6Al4V. Finally, the stress distribution in the models was compared with the results of previous studies on commercial implants. The results of the finite element analysis show that there are considerable differences in the magnitude of the equivalent stress in the models in static and dynamic phases. Also, changes in the defined geometric parameters have significant effects on the stress distribution in terms of Von Mises stress in the overall models. The experimental results indicated good agreement with those of the modeling. It can be concluded that some porous structures with optimal geometries can be proposed as a new structure for dental implants. However, considering the physiology of bone when confronted with porous structures, further studies such as in vivo experiments are needed in this field.

TGF-β Signaling in Cranial Neural Crest Affects Late-Stage Mandibular Bone Resorption and Length.

Malocclusions are common craniofacial malformations which cause quality of life and health problems if left untreated. Unfortunately, the current treatment for severe skeletal malocclusion is invasive surgery. Developing improved therapeutic options requires a deeper understanding of the cellular mechanisms responsible for determining jaw bone length. We have recently shown that neural crest mesenchyme (NCM) can alter jaw length by controlling recruitment and function of mesoderm-derived osteoclasts. Transforming growth factor beta (TGF-β) signaling is critical to craniofacial development by directing bone resorption and formation, and heterozygous mutations in TGF-β type I receptor (TGFBR1) are associated with micrognathia in humans. To identify what role TGF-β signaling in NCM plays in controlling osteoclasts during mandibular development, mandibles of mouse embryos deficient in the gene encoding Tgfbr1 specifically in NCM were analyzed. Our lab and others have demonstrated that Tgfbr1fl/fl;Wnt1-Cre mice display significantly shorter mandibles with no condylar, coronoid, or angular processes. We hypothesize that TGF-β signaling in NCM can also direct later bone remodeling and further regulate late embryonic jaw bone length. Interestingly, analysis of mandibular bone through micro-computed tomography and Masson's trichrome revealed no significant difference in bone quality between the Tgfbr1fl/fl;Wnt1-Cre mice and controls, as measured by bone perimeter/bone area, trabecular rod-like diameter, number and separation, and gene expression of Collagen type 1 alpha 1 (Col1α1) and Matrix metalloproteinase 13 (Mmp13). Though there was not a difference in localization of bone resorption within the mandible indicated by TRAP staining, Tgfbr1fl/fl;Wnt1-Cre mice had approximately three-fold less osteoclast number and perimeter than controls. Gene expression of receptor activator of nuclear factor kappa-β (Rank) and Mmp9, markers of osteoclasts and their activity, also showed a three-fold decrease in Tgfbr1fl/fl;Wnt1-Cre mandibles. Evaluation of osteoblast-to-osteoclast signaling revealed no significant difference between Tgfbr1fl/fl;Wnt1-Cre mandibles and controls, leaving the specific mechanism unresolved. Finally, pharmacological inhibition of Tgfbr1 signaling during the initiation of bone mineralization and resorption significantly shortened jaw length in embryos. We conclude that TGF-β signaling in NCM decreases mesoderm-derived osteoclast number, that TGF-β signaling in NCM impacts jaw length late in development, and that this osteoblast-to-osteoclast communication may be occurring through an undescribed mechanism.

Proteomic profile of tissue-derived extracellular vesicles from benign odontogenic lesions

BackgroundBenign odontogenic lesions (BOLs) can cause severe jaw bone defects and compromise the quality of life of patients. Extracellular vesicles (EVs) are well-established and versatile players in mediating pathophysiological events. EVs in the interstitial space (tissue-derived EVs or Ti-EVs) possess higher specificity and sensitivity in disease-related biomarker discovery. However, the role of Ti-EV-loaded proteins in mediating the development of BOLs has remained untapped. Herein, we aim to explore the contribution of Ti-EV-loaded proteins to the development of BOLs. MethodsSamples were obtained from 3 with dental follicle, 3 with dentigerous cyst (DC), 7 with odontogenic keratocyst (OKC), and 3 patients with ameloblastoma (AM). Tissue-derived EVs were then extracted, purified, and validated using ultracentrifugation, transmission electron microscopy, and western blotting. Proteins from Ti-EVs were analyzed using LC-ESI tandem mass spectroscopy and differentially expressed proteins were screened, which was then validated by immunohistochemistry and immunofluorescence assays. ResultsThe protein profile of Ti-EVs in each group was mapped by LC-MS analysis. The top 10 abundant proteins in BOL-derived Ti-EVs were COL6A3, COL6A1, ALB, HIST1H4A, HBB, ACTB, HIST1H2BD, ANXA2, COL6A2 and FBN1. Additionally, unique proteins in the Ti-EVs from various lesions were identified. Moreover, focal adhesion kinase (FAK) and myeloid differentiation primary response 88 (MyD88) showed higher expressions in Ti-EVs derived from OKC and AM, which were confirmed by immunohistochemistry and immunofluorescence staining. ConclusionsTi-EVs containing FAK and MyD88 might be related to the development of OKC and AM, which can be potential therapeutic targets.

CURRENT POSSIBILITIES AND PROSPECTS OF ALVEOLAR BONE DEFECT REPLACEMENT AND COVERING TISSUES: NARRATIVE LITERATURE REVIEW

BACKGROUND: The percentage of the need to increase the volume of supporting tissues remains high - from 43% to 77%, despite the fact that the currently used approaches for augmentation of tissue structures do not always show the expected results. A common cause of problems with the growth of new supporting tissues is the reduced activity of inducing factors of local and systemic levels in the human body. A critical deficiency of the integumentary structures significantly affects the result of reconstructive and reconstructive surgical interventions.Objective: to characterize the modern achievements of intraoral reconstruction of volumetric defects of supporting tissues, including bioengineering for the regeneration of the alveolar jaw bone and integumentary structures.Methods. The search strategy included an electronic search of literature sources performed in the PubMed database using keywords. The formats "Review", "Systematic Review" and "Clinical Trial" were requested. The search depth was 20 years.Results. Of the 378 articles found, 44 met the inclusion criteria set for this review. The prerequisites for the reconstruction of the alveolar ridge with an emphasis on early vascularization of de novo tissues are outlined, the advantages and disadvantages of bone and soft tissue grafts are characterized. The results of research efforts using mesenchymal stem cells, which play a crucial role in the regeneration of the alveolar bone and gum, are presented. The evolution of tissue engineering structures for integumentary tissues is presented – from thin layers of epithelial cells to 3D – epithelized equivalents of the oral mucosa.Conclusion. The rapidly increasing number of biomaterial studies involving stem cells, the active development of tissue engineering indicates the prospects for the development of biomaterials of the next generations, which will be able to work effectively together with their own mechanisms of tissue regeneration in their unique architecture.

Diversity in the internal functional feeding elements of sympatric morphs of Arctic charr (Salvelinus alpinus).

The diversity of functional feeding anatomy is particularly impressive in fishes and correlates with various interspecific ecological specializations. Intraspecific polymorphism can manifest in divergent feeding morphology and ecology, often along a benthic-pelagic axis. Arctic charr (Salvelinus alpinus) is a freshwater salmonid known for morphological variation and sympatric polymorphism and in Lake Þingvallavatn, Iceland, four morphs of charr coexist that differ in preferred prey, behaviour, habitat use, and external feeding morphology. We studied variation in six upper and lower jaw bones in adults of these four morphs using geometric morphometrics and univariate statistics. We tested for allometric differences in bone size and shape among morphs, morph effects on bone size and shape, and divergence along the benthic-pelagic axis. We also examined the degree of integration between bone pairs. We found differences in bone size between pelagic and benthic morphs for two bones (dentary and premaxilla). There was clear bone shape divergence along a benthic-pelagic axis in four bones (dentary, articular-angular, premaxilla and maxilla), as well as allometric shape differences between morphs in the dentary. Notably for the dentary, morph explained more shape variation than bone size. Comparatively, benthic morphs possess a compact and taller dentary, with shorter dentary palate, consistent with visible (but less prominent) differences in external morphology. As these morphs emerged in the last 10,000 years, these results indicate rapid functional evolution of specific feeding structures in arctic charr. This sets the stage for studies of the genetics and development of rapid and parallel craniofacial evolution.

Evolutionary trends in the elasmobranch neurocranium

The neurocranium (braincase) is one of the defining vertebrate characters. Housing the brain and other key sensory organs, articulating with the jaws and contributing to the shape of the anteriormost portion of the body, the braincase is undoubtedly of great functional importance. Through studying relationships between braincase shape and ecology we can gain an improved understanding of form-function relationships in extant and fossil taxa. Elasmobranchii (sharks and rays) represent an important case study of vertebrate braincase diversity as their neurocranium is simplified and somewhat decoupled from other components of the cranium relative to other vertebrates. Little is known about the associations between ecology and braincase shape in this clade. In this study we report patterns of mosaic cranial evolution in Elasmobranchii that differ significantly from those present in other clades. The degree of evolutionary modularity also differs between Selachii and Batoidea. In both cases innovation in the jaw suspension appears to have driven shifts in patterns of integration and modularity, subsequently facilitating ecological diversification. Our results confirm the importance of water depth and biogeography as drivers of elasmobranch cranial diversity and indicate that skeletal articulation between the neurocranium and jaws represents a major constraint upon the evolution of braincase shape in vertebrates.

Short (≤6 mm) compared with ≥10-mm dental implants in different clinical scenarios: A systematic review of randomized clinical trials with meta-analysis, trial sequential analysis and quality of evidence grading.

To systematically identify, synthesize and critically summarize the available scientific evidence from randomized controlled trials (RCTs) regarding whether short (≤6 mm) perform as well as long (≥10 mm) implants regarding implant survival, marginal bone loss, and biologic and prosthetic complications in different clinical scenarios. Cochrane Collaboration's risk of bias tool and the GRADE approach were applied. Results were synthesized using random-effects meta-analyses assessed by trial sequential analyses. Forty reports on 19 RCTs comprising 2214 (1097 short; 1117 long) implants were included. Moderate/high certainty/quality evidence demonstrated similar 5-year survival rates for ≤6-mm and ≥10-mm implants in non-augmented bone and full-mouth rehabilitation in either jaw, and for 6-mm implants in the maxilla instead of sinus lift. Nevertheless, the evidence for 5-year survival rates remains inconclusive or insufficient for the remaining combinations of implant lengths and clinical scenarios. They include 4-mm and 5-mm implants as alternatives to sinus lift as well as placing all implant lengths ≤6 mm instead of vertical ridge augmentation with long implants. Marginal bone level and short- and long-term biologic or prosthetic complications were similar. Based on moderate/high certainty/quality evidence from 5-year RCTs, implants ≤6 mm may be viable alternatives to ≥10-mm implants in either jaw in native bone and full-arch rehabilitation, and 6-mm implants may be used as an alternative to sinus lift. PROSPERO ID: CRD42021254365.

Exploring Prevalence Trends of Jaw Bone Pathologies: A Three-Year Institutional Study.

Background Head and neck bone pathologies cover various conditions with diverse causes. Infections like osteomyelitis and dental abscesses can spread to soft tissues and bones, causing tissue death, inflammation, and systemic effects. Benign and malignant tumors can develop from soft tissue, cartilage, or bone, posing challenges for diagnosis and treatment. Studies on their prevalence in local populations are rare, obscuring our understanding of regional health dynamics. Aim In this study, we aimed to assess the prevalence of bone pathologies documented over the last three years from 2021 to 2023. Materials and methods Histopathologically confirmed cases of bone pathologies at Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, India, were gathered from the institutional database (DIAS: Dental Information Archiving Software) from January 1, 2021, to December 31, 2023. They were categorized into groups of infectious and inflammatory lesions, fibro-osseous lesions, malignancies originating from bone, malignancies invading bone, and miscellaneous conditions. The data was then compiled into a Google spreadsheet (Google, Inc., Mountain View, USA) for further analysis. Graphs were created to visualize the prevalence of bone pathologies enabling a descriptive exploration of temporal trends. Results A total of 2626 biopsy records were reviewed. Among these, 242 (9.21%) cases of bone-related pathologies were included, and the remaining 2384 (90.79%) entities without any mention of bone were excluded. Overall, considering all three years, 43.8% (100) bone-related lesions were reported in 2021, 30.3% (77) in 2022 and 25.9% (65) in the year 2023. Under each category, infectious and inflammatory lesions for 40.5% (98), fibro-osseous lesions for 14.9% (36), benign lesions for 2.9% (7), malignancies originating from bone for 1.7% (4), malignancies invading bone for 38% (93), and miscellaneous conditions for 1.65% (4) were reported. The highest number of infectious and inflammatory pathologies (53%) were reported in 2021. A steep fall was observed in 2022 and 2023 under the infectious and inflammatory category. The malignancies invading the bone showed almost similar distribution in all three years. Conclusion The observed variations highlight the unpredictability of bone pathologies, involving the jaw bones. We emphasize continuous observation and analysis to comprehend changing patterns in bone health.

Clinical Outcomes of Polyetheretherketone (PEEK) Hybrid Prosthesis in All-on-Four Rehabilitation: A Systematic Review Protocol

Background The “all-on-four” concept represents a significant advancement in dental implantology. particularly beneficial in cases of extensive jaw bone loss where invasive bone regeneration procedures are typically required. However, the successful implementation of this technique necessitates meticulous planning concerning implant selection, materials, and prosthesis design. The recent introduction of PEEK (Polyetheretherketone) in dentistry, especially in all-on-four prosthetics, prompts questions regarding its clinical efficacy and comparative biomechanical and biological advantages over conventional materials such as titanium and zirconia. While some studies have compared PEEK with other materials, systematic reviews evaluating its efficacy are scarce. This systematic review protocol intends to assess the evidence regarding the viability of PEEK as a potential alternative within the all-on-four approach in dental implantology. Methods This systematic review protocol will adhere to the Cochrane Handbook for Systematic Review of Interventions and align with the Methodological Expectations of the Cochrane Intervention Reviews (MECIR) guidelines. Utilizing a comprehensive search strategy, multiple databases, including PubMed, EMBASE, Scopus, EBSCO, Web of Science, Cochrane Central, and registries of clinical trials, will be explored. The search aims to identify randomized controlled trials and non-randomized studies investigating the application of PEEK in the all-on-four approach for dental procedures. Emphasizing clinically relevant outcomes such as implant survival, prosthesis success, peri-implant complications, and patient satisfaction, this review aims to provide insights into the effectiveness and potential benefits of using PEEK in all-on-four prosthetics. Non-randomized studies will be assessed for bias using ROBINS-I, while randomized controlled trials will undergo evaluation with the Cochrane Risk of Bias assessment tool, ROB II. Discussion The outcomes derived from this systematic review hold great significance for dental practitioners exploring the all-on-four concept. Understanding PEEK’s advantages and limitations compared to titanium and zirconia facilitates tailored treatment plans, enhancing success and satisfaction, ultimately improving dental care quality. Systematic review registration PROSPERO: CRD42024531175 (Registered on 13/04/2024).

Profile and Prevalence of Oral and Maxillofacial Diseases Among Armed Forces Personnel and Their Families in Military Dental Centre, Cumilla

Background: Oral and maxillofacial diseases encompass a wide range of conditions in and around oral cavity and in maxillofacial region. It includes maxillofacial trauma, cyst and tumour of jaw bones, conditions involving impacted wisdom teeth, oral premalignant and malignant lesions, fascial space infection around maxillofacial region, temporomandibular joint disorder, dental implantology, salivary gland disorder and congenital defects of jaw bones. Maxillofacial region is more vulnerable to sustain injuries in the battlefield. In peace time, various maxillofacial diseases reduce the overall performances of the troops. The aim of this study is to delineate rank wise distribution of armed forces personnel reported with maxillofacial diseases, gender distribution, types of maxillofacial diseases, different types of surgical procedures performed and types of anesthesia used. Methods: A descriptive cross-sectional study was conducted to assess the prevalence of maxillofacial diseases among the armed forces personnel and their entitled family members during the period of 1st January 2019 to 31st December 2019 in Military Dental Centre, Cumilla. Purposive sampling technique and semi structured questionnaire was used to include the patients in this study.Data were analyzed by using Statistical Packages for Social Sciences (SPSS) version 25. Results: A total of 170 cases were evaluated and treated. Male patients were 110(65%) and female were 60(35%). Among the military personnel numbers of sainik (privates) were highest 32(35%). Impacted wisdom teeth cases were mostly found 80(47%). In case of impacted teeth mesio angular impactions were most 35(35%). In case of maxillofacial pathological conditions cystic lesions were most in number 22(39%) (n=56). Maxillofacial soft tissue laceration cases were highest 05(29%) (n=17) among all trauma patients. Surgical extraction of wisdom teeth were mostly performed surgery 80(59%) (n=138). In regards to administration of anesthesia, 128(93%) cases were performed under local anesthesia and 10(7%) were under general anesthesia. Conclusion: The present study imparts valuable perception about the types and prevalence of maxillofacial diseases and the treatment modalities among the armed forces personnel and their families in Cumilla area. Bangladesh Armed Forces Med J Vol 56 No (2) December 2023, pp 24-30

Diagnostic assessment of jaw bone density in school-age children using chewing gum

Relevance. The article is devoted to the issue of diagnosing the condition of the jaw bone tissue in children with mixed dentition. The relevance of the study is related to the increased consumption of chewing gum by children.The purpose of this study was to evaluate the echodensity of the jaw bone tissue in patients with mixed dentition using chewing gum with varying intensity.Materials and methods. We examined 31 children, the average age was 8.5±1.2 years. It is at this age that the active formation of facial morphology and anatomy takes place, which is directly related to the condition of the jaw bones. For diagnosis, an ultrasound technique was chosen – osteometry. This method is based on assessing the speed of propagation of ultrasound waves along the surface of the bone. In addition, in comparison with radiation, ultrasound methods for studying bone tissue have significant advantages, expressed in the reliability of the results obtained, low cost of procedures, ease of use, absence of radiation for personnel and patients, and minimal research time. From a practical point of view, this method is the most accessible in a dental office. Echoosteometry was carried out using the Echoosteometer EOM-01TS apparatus.Results. Based on the study, it was revealed that there was an imbalance in bone density in children who actively used chewing gum.

Temporary skeletal anchorage – possibilities and mechanism of application. Literature review

To date, the use of a temporary skeletal anchorage in orthodontic treatment in almost every clinical case. Despite this, there are only two variants of this surgical instrument: mini-screws and mini-plates. Both variants of the skeletal anchorage have their positive and negative qualities, which, to one degree or another, affect the result and timing of treatment. The purpose of this literature review is to describe the main methods of using temporary skeletal anchorage, in which clinical cases their use is possible and contraindicated, as well as what positive and negative aspects can be observed during and after the treatment of orthodontic patients. The search for scientific data was carried out in the PubMed database using such keywords as: orthodontic skeletal anchorage, temporary anchorage, orthodontic mini-screw, orthodontic mini-plate. A literature search revealed that temporary skeletal anchorage allows the surgeon and orthodontist to predictably make changes to the jaw bones that were previously only possible with orthognathic surgery. Before installing a mini-screw or mini-plate, careful planning in the form of an examination and x-ray examination should be carried out. Ultimately, informed consent should be obtained explaining to the patient that orthognathia may still be necessary if the skeletal anchorage method fails. Although this is still a relatively new technique, some issues need to be considered and further clinical research is needed.

Pathogen identification and epidemic factor analysis of yellow catfish, Pelteobagrus fulvidraco, red lower jaw disease

Since 2020, another type of epidemic disease, ‘red lower jaw disease’ (RLJD), has broken out in yellow catfish Pelteobagrus fulvidraco every spring in China, causing large-scale deaths and significant economic losses. This new disease has the characteristics of strong infectivity, high mortality and a single host. To prevent and control RLJD, epidemiological investigation, transmission electron microscopy (TEM), virome sequencing, Koch's rule verification and epidemic factor investigation were studied in this article. The clinical symptoms of diseased yellow catfish were pale gill filaments, hyperaemia and swelling of the spleen and kidney. TEM results revealed that a large number of 35–40 nm spherical virus particles without envelope structure were found in the cytoplasm of spleen cells. The liver, spleen and kidney of the diseased fish had serious lesions. After virome sequencing, the calicivirus reads in the unique virus reads accounted for 99.5% of the unique virus reads in the diseased fish, which provided a relevant reference value for identifying the pathogen of RLJD. The full-length sequence of yellow catfish calicivirus (YCCV) obtained at 7405 bp, including the RNA-helicase domain, RdRp-1 domain and d1iqqa domain. At the same time, both PCR and TaqMan fluorescence quantitative PCR detection method of YCCV were established. Through the artificial infection test, YCCV was verified as the pathogen for RLJD. It was also found that YCCV mainly harmed the fish within 1 year, whereas the fish above 2 years had good resistance. The water temperature of the RLJD outbreak was mainly concentrated at 18 °C–24 °C. In the current study, after YCCV was verified as the pathogen of RLJD, epidemic factors including fish age and water temperature were studied, to the best of our knowledge, for the first time to provide a relevant theoretical basis for the pathogenic mechanism and prevention and control measures of yellow catfish RLJD.

Long-term survival rates of tapered self-tapping bone-level implants after immediate placement: a positional effective rationale

BackgroundImmediate implant placement has gained popularity due to its several advantages. However, immediate placement has its challenges, including concerns about primary stability and bone formation around the implant. The aim of the present study is to evaluate the clinical outcomes of tapered, sand-blasted, and acid-etched internal submerged dental implants in various regions of the jaw bones and to provide a positional rationale for immediate implant placement.MethodsBetween 2009 and 2018, a single surgeon at Seoul National University Dental Hospital in Seoul, Korea, immediately inserted 49 dental implants with tapered bone-level design after extraction, in a total of 34 patients. The clinical outcomes were collected and evaluated, focusing on location of implant placement and marginal bone loss (MBL), with consideration of other parameters such as implant diameter and length.ResultsOf 49 immediately installed Luna® (Shinhung Co., Seoul, Korea) dental implants, 23 were placed in the mandible, and 26 were set in the maxilla. The mean age of patients at the time of installation was 65.91 years, ranging from 40 to 86 years. The average follow-up period was 7.43 years, with a range of 5 to 14 years. After a 5-year retrospective evaluation of tapered, sand-blasted, and acid-etched internal submerged dental implants for immediate implant placement, the cumulative survival rate was 93.88%, with 100% survival rate in the mandible and premolar region of both the maxilla and mandible.ConclusionsAfter a 5-year evaluation, tapered, sand-blasted, and acid-etched internal submerged dental implants demonstrated good efficacy for immediate placement in various locations within the dental arches, exhibiting effective clinical performance.

Study on liver tissue derived-extracellular vesicles regulating the osteogenic differentiation ability of mesenchymal stem cells and promoting the healing of jaw bone defects

Objective: To explore the biological process of liver tissue-derived extracellular vesicle (LT-EV) in promoting osteogenic differentiation of mesenchymal stem cells and healing of jaw defects to provide a feasible treatment method for the clinical treatment of jaw bone defects. Methods: Enzymatic hydrolysis and differential centrifugation were used to extract LT-EV, scanning electron microscopy, Western blotting, and nanoparticle tracking analyzers were used to identify and characterize LT-EV, and further to explore the biological functions of LT-EV through proteomics and Kyoto Encyclopedia of Genes and Genomes. Flow cytometry was used to detect LT-EV plasma concentration and to calculate the plasma half-life of LT-EV. Small animal in vivo imaging system was used to detect the biological distribution of LT-EV 24 hours after injection. Six C57BL/6 mice were divided into control group and LT-EV group (3 mice in each group) by simple random sampling method. All mice underwent jaw bone defect surgery and tail vein injection every 7 days (the control group was injected with phosphoric buffer saline, LT-EV group was injected with LT-EV), micro-CT was used to evaluate the degree of mouse jaw bone healing 28 days after surgery, HE staining was used to analyze the multi-organ biosafety of LT-EV, and immunofluorescence staining was used to detect the jaw bone expression of osteogenic marker proteins in the defect area. Human jaw bone mesenchymal stem cells (hJBMSC) induced by osteogenic differentiation were treated with LT-EV (obtained from orthognathic surgery patients provided by the Department of Traumatology and Orthognathic Surgery of School of Stomatology of The Fourth Military Medical University resected normal jaw bone fragments), and the difference in osteogenic differentiation ability between the hJBMSC group and the control group (phosphate buffer saline treatment) was compared, and the in vitro bone differentiation promoting effect of LT-EV was verified through alkaline phosphatase (ALP) staining and real-time fluorescence quantitative PCR. Results: The yield of LT-EV was high, and proteomics and Kyoto Encyclopedia of Genes and Genomes showed that LT-EV contained a series of proteins that regulated cell biological functions. LT-EV injected into the tail vein could reach the mouse jaw bone defect area and promote the regeneration and repair of the jaw bone defect [the bone volume fractions of the LT-EV group and the control group were (36.06±4.20)% and (18.58±5.61)%, respectively; t=4.32, P=0.013], and had good biosafety. LT-EV could promote osteogenic differentiation of hJBMSC in vitro. Compared to the control group, ALP staining and osteogenic gene expression levels were significantly enhanced after osteogenic differentiation of hJBMSC (P<0.05). Conclusions: LT-EV exhibits a high yield, ease of acquisition, high biological safety, and excellent bone-promoting effects. It holds promise as a novel cell-free therapy strategy for regenerating craniofacial bone defects.

The influence of immediate occlusal loading on micro/nano-structure of peri-implant jaw bone in rats

PurposeThe objective of the present study was to ascertain the effect of immediate occlusal loading after implant placement on osseointegration and the micro/nanostructure of the surrounding bone.MethodsAfter extraction of a rat maxillary right second molar, an implant was placed immediately with initial fixation (2 N< ). The implants were placed to avoid occlusal loading due to mastication, and in the loaded group, a superstructure was fabricated and subjected to occlusal loading. Bone morphometry, collagen fiber anisotropy, and biological apatite (BAp) crystallite alignment were quantitatively evaluated in both groups after extraction and fixation of the jaw bone at Days 7 and 21 after surgery.ResultsOsseointegration was observed in both groups. Bone morphometry showed significant differences in bone volume, trabecular number, trabecular thickness and bone mineral density (BMD) at Days 21 postoperatively (P < 0.05). A significant difference was also found in the trabecular separation at Days 7 postoperatively (P < 0.05). In the evaluation of collagen fiber anisotropy, collagen fiber bundles running differently from the existing bone were observed in both groups. In terms of BAp crystallite alignment, a specific structure was observed in the reconstructed new bone after implantation, and preferential orientation of BAp crystallite alignment was observed in the longitudinal direction of the implants in the Day 21 postoperative loaded group.ConclusionWhen sufficient initial fixation is achieved at the time of dental implant placement, then the applied masticatory load may contribute to rapidly achieving not only bone volume, but also adequate bone quality after implant placement.

An unusual presentation of unifocal Rosai-Dorfman disease and surgical treatment

Rosai-Dorfman disease (RDD) is a rare histiocytic disorder with an unclear aetiology, and commonly presents with painless, bilateral cervical lymphadenopathy. Extranodal presentation in the absence of nodal involvement has been reported to have a predilection for the head and neck with less than 20 cases involving the jaw bones and sinuses. We present an interesting case of unifocal RDD of the infratemporal space in the absence of nodal involvement in a 61-year-old female treated with surgical excision and adjuvant radiation therapy.

A Critical Review of Human Jaw Biomechanical Modeling

The human jaw is a complex biomechanical system involving different anatomical components and an articulated muscular system devoted to its dynamical activation. The numerous actions exerted by the mandible, such as talking, eating or chewing, make its biomechanical comprehension absolutely indispensable. To date, even if research on this topic has achieved interesting outcomes using in vitro testing, thanks to the development of new apparatus and methods capable of performing more and more realistic experiments, theoretical modeling is still worthy of investigation. In light of this, nowadays, the Finite Element Method (FEM) approach constitutes certainly the most common tool adopted to investigate particular issues concerning stress–strain characterization of the human jaw. In addition, kinematics analyses, both direct and inverse, are also diffuse and reported in the literature. This manuscript aimed to propose a critical review of the most recurrent biomechanical models of the human mandible to give readers a comprehensive overview on the topic. In light of this, the numerical approaches, providing interesting outcomes, such as muscular activation profiles, condylar forces and stress–strain fields for the human oral cavity, are mainly differentiated between according to the joint degrees of freedom, the analytical descriptions of the muscular forces, the boundary conditions imposed, the kind of task and mandible anatomical structure modeling.

Correlating Jaw Bone Growth and Nasal Morphology Among Adult Patients With Cleft Lip and Palate: A Retrospective Cephalometric Study.

This retrospective cross-sectional study reviewed adult patients with operated cleft lip and/or palate (CL/P) and normal control, and performed comprehensive craniofacial and nasal morphological analyses based on lateral cephalometric radiographs. Pearson or Spearman correlation coefficient assessed intraclass correlation. Seven hundred fifty-seven operated patients with CL/P, and 165 noncleft normal controls were enrolled. Among the normal and CL/P groups, S-N-A angle registered positive correlations with nasal base prominence (S-N'-Sn, degrees). Upper facial height (N-ANS, mm) had positive correlations with nasal dorsum length (N'-Prn, mm) and nasal bone length (N-Na, mm). Although in patients with bilateral cleft lip and palate, there were moderate negative correlations ( r =-0.541, P <0.05) with soft tissue facial profile angle (FH-N'Pog', degree) and nasolabial angle (Cm-Sn-ULA, degree). Correlation exists between the morphology of jaw bones and external nose among patients with CL/P. Maxillary sagittal insufficiency is associated with concave nasal profile, and maxilla height is associated with nasal length.

Postural balance in the comprehensive rehabilitation of adolescents with cleft lip and palate and maxillofacial anomalies: A literature review

BACKGROUND: Patients with cleft lip and palate experience significant jaw relationship disorders and pathological bite formation, leading to changes in the motor activity of chewing muscles and postural balance disturbances. Most studies on postural control are conducted on patients with skeletal dentofacial anomalies and deformities without cleft lip and palate. The state of postural balance in children with cleft lip and palate requiring long-term complex medical rehabilitation, including bone-reconstructive operations on the jaw bones, remains poorly understood.&#x0D; AIM: To analyze publications dedicated to the evaluation of postural balance in adolescents with cleft lip and palate combined with jaw relationship disorders and pathological bite formation.&#x0D; MATERIALS AND METHODS: The article includes an analysis and review of several studies that investigated the state of postural balance in adolescents with cleft lip and palate, particularly at the final stages of growth and formation of the musculoskeletal system. Scientific articles published in various medical journals, monographs, dissertations, and materials from scientific symposiums related to this topic were used in the literature review. PubMed, Medline, Scopus, Web of Science, and RSCI were searched without language restrictions. The search depth was 23 years, and 64 studies were selected.&#x0D; RESULTS: The article analyzes literature data related to theories of the mechanism of mutual influence between postural balance and the dentofacial apparatus (disorders and pathological bite formation). The state of postural balance is influenced by various factors, including the craniosacral system and anomalies of the cervical spine. Patients with cleft lip and palate, hemifacial microsomia, and other craniofacial dysostoses with growth disorders of jaw bones experience an imbalance in the entire “descending” chain, causing postural disturbances, increased plantar pressure, increased foot rigidity, and changes in photogrammetry indicators, which should be considered when developing an individual rehabilitation program for these patients. The treatment of these patients without considering postural balance disorders can lead to temporomandibular joint pathologies, unstable results of the conservative orthodontic treatment of bite pathologies, and bone-reconstructive operations on jaws.&#x0D; CONCLUSIONS: The study highlights the ways of adaptation of the musculoskeletal system in the presence of occlusal relationship disorders and emphasizes the need to evaluate this influence comprehensively for the treatment of these patients. The limitations of the presented studies should be emphasized: insufficient sample size, lack of control groups and prospective studies, limited types of examination, and lack of studies dedicated to more severe anomalies of craniofacial development.