Significant Resorption Research Articles

Effect of initial bone morphology on alveolar bone remodeling following molar extraction: A retrospective study.

The clinical evidence about alveolar ridge changes following molar extraction and how the alveolar bone morphology influences the ridge dimensional changes remains limited. A total of 192 patients with 199 molar extractions were included in this retrospective study. Cone-beam computed tomography (CBCT) images of patients were obtained 0-3 months pre extraction and 6-12 months post extraction. Outcome variables included the change rate in ridge height and width. The effect of morphology on the outcomes was explored by single-factor analysis, correlation analysis, and a multiple linear regression model. Significant resorption of alveolar bone occurred vertically and horizontally after molar extraction. Jaw, furcation involvement, number of roots, number of bone wall defects, extraction reasons, overall relative bone loss (RBL), bone height of the furcation region, thickness of the lingual/palatal wall, and height difference between buccal and lingual/palatal walls (|HB-HL|) were significantly correlated with the change in the height of the central alveolar bone (HC). The number of bone wall defects, overall RBL, and |HB-HL| were significantly correlated with horizontal width change. HC resorption was higher in sockets with |HB-HL|>2.5mm and overall RBL>50%. The alveolar bone presented significant resorption after extraction. Anatomical characteristics affected the dimensions of the alveolar bone after molar extraction. When the initial overall RBL was severe or |HB-HL| was larger, the loss of alveolar bone dimensions was even more. In recent years, it has been demonstrated that the local anatomical morphology of extraction sites may influence the process of alveolar bone remodeling. However, most studies have focused on the anterior teeth, with fewer investigations addressing molar extraction sites. Therefore, we aimed to describe ridge changes following molar extraction and investigate how alveolar bone morphology influences ridge dimensional changes. In this retrospective study, we included a total of 199 alveolar sockets from 192 patients with molar extractions and obtained the corresponding cone-beam computed tomography (CBCT) images 0-3 months pre extraction and 6-12 months post extraction. The results showed significant resorption of the alveolar bone following molar extraction. We found that anatomical characteristics significantly affect the dimensions of the alveolar bone after molar extraction. Specifically, the loss of alveolar bone dimensions was greater when the initial overall relative bone loss (RBL) was severe or when the difference between buccal and lingual/palatal walls was greater.

Analysis of bone quality formation in sinus lifts with immediate implants

Sinus lift surgeries are part of the daily practice of dentists. This study evaluates the long-term structure of the bone placed in sinus lifts through the fractal dimension. We conducted a retrospective study on a sample of 35 patients with 51 sinus lifts performed using a lateral window approach and filling material placement. We radiologically analyzed the graft bone to observe its evolution up to one and a half years after the surgical procedure. The obtained results were the average area of the sinuses analyzed was 1401.96 mm2, with a mean area occupied by the filling material of 297.75 mm2. Significant differences are observed when comparing the fractal dimension values obtained on the initial day and one year after prosthesis loading. Similarly, when comparing the values of the area occupied by the biomaterial at the start day and one year after prosthesis loading, significant differences are also obtained (p-value < 0.001). In conclusion, the filling material used in the lateral window sinus lift procedure undergoes significant resorption and shows changes in the fractal dimension.

The Evolution of Custom Subperiosteal Implants for Treatment of Partial or Complete Edentulism in Patients with Severe Alveolar Ridge Atrophy.

Dental implants have always played an important role in dentistry and have been used to replace missing teeth since around 600 AD. They can be classified into three groups: endosteal, subperiosteal, and transosteal. Over time, different materials have been used to manufacture dental implants and these, in turn, can be divided into three groups: metals, ceramics, and polymers. Today, the most commonly used treatment for edentulism is the use of endosteal implants. However, such an approach cannot be used in patients with severe alveolar ridge atrophy and, in such cases, custom subperiosteal implants are an alternative. This review article focuses on historical developments and improvements that have been made over recent years in treatment options for patients suffering from edentulism and significant resorption of the alveolar ridge. These treatment options involve the utilization of custom subperiosteal implants. This paper looks at the historical evolution of these implants, the significance of diagnostic imaging, and the application of the contemporary methods of production, such as CAD-CAM and additive manufacturing. The research emphasizes the importance of accuracy and personalization provided by these emerging technologies that have rendered subperiosteal implants a more feasible and less intrusive alternative for patients suffering from significant bone loss.

Genetic polymorphisms linked to extreme postorthodontic external apical root resorption in Koreans

BackgroundExternal apical root resorption (EARR) is a common undesirable outcome of orthodontic treatment, this study aimed to identify genetic polymorphisms associated with the susceptibility to extreme orthodontic-induced EARR in a Korean population using extreme phenotype analysis sampling.MethodsGenomic DNA was isolated from the saliva of 77 patients who underwent orthodontic treatment involving two maxillary premolar extractions. The patients were divided into two groups based on EARR values measured on periapical radiographs: The significant resorption group (SG, EARR ≥ 4 mm) and the normal group (NG, EARR < 2 mm). In the NG group, patients with EARR < 1 mm were named the non-resorption group (NonG). Targeted next-generation sequencing was performed using the screened single nucleotide polymorphisms (SNPs), and firth logistic regression analysis was used to determine genetic associations with EARR. Haplotype-based association analysis was performed for specific SNPs.ResultsSNPs related to genes TNFSF11, TNFRSF11B, WNT3A, SFRP2, LRP6, P2RX7, and LRP1 were found to be significantly associated with severe EARR (p < 0.05, pre-Bonferroni correction p-values). Additionally, the haplotype CCA of rs17525809, rs208294, and rs1718119 P2RX7 had a higher frequency in the SG group.ConclusionExtreme phenotype analysis has identified eleven SNPs related to genes TNFSF11, TNFRSF11B, WNT3A, SFRP2, LRP6, P2RX7, and LRP1 that are associated with severe root resorption in the Korean population. These findings will contribute to the development of predictive diagnostic tools for identifying severe root resorption that may occur during orthodontic treatment.

Integrated Approach in the Treatment of a Patient with Tuberculosis of the Lungs and Tracheobronchial Tree

Introduction. According to the World Health Organization data for 2021, there is an increase in the incidence of tuberculosis (TB) worldwide. There is also an unfavorable growth trend in drug-resistant TB. One of the complications of the tuberculosis process is tuberculosis of the tracheobronchial tree, which has tended to grow in recent years. Many studiesindicate the incidence of bronchial tuberculosis from 10 to 40 %, taking into account the level of endoscopic service.The purpose of the study to demonstrate the high effectiveness of an integrated approach in the treatment of a patient with tuberculosis of the lungs and tracheobronchial tree.Methods. The materials of the study were: the outpatient card of the advisory department of the Central Tuberculosis Research Institute, the medical history of the inpatient patient and the results of a comprehensive examination.Results. The presented clinical example demonstrates the high effectiveness of an integrated approach in the treatment of a patient with a widespread tuberculosis process using anti-tuberculosis chemotherapy, inhalation and pathogenetic therapy. By 4 months of treatment, pronounced positive clinical and laboratory dynamics was observed, significant resorption of focal infiltrative changes in the leſt lung was achieved radiologically, and endoscopically, infiltrative tuberculosis of the trachea, leſt main bronchus and leſt upper lobe bronchus was cured.Conclusion. This clinical observation demonstrates the need for an integrated approach in the management of this category of patients and shows the high effectiveness of the treatment.

NOVEL APPROACH: PERCUTANEOUS INJECTION OF BONE-SUBSTITUTE (CERAMENT-GTM) TO AID BONY HEALING IN STIFF NONUNITED COMPLEX OPEN TIBIAL FRACTURES

IntroductionTreatment of non-union in open tibial fractures Gustilo-Anderson(GA)-3A/3B fractures remains a challenging problem. Most of these can be dealt using treatment methods that requires excision of the non-union followed by bone grafting, masquelet technique, or acute shortening. Circular fixators with closed distraction or bone transport also remains a useful option. However, sometimes due to patient specific factors these cannot be used. Recently antibiotic loaded bone substitutes have been increasingly used for repairing infected non-unions. They provide local antibiotic delivery, fill dead space, and act as a bone conductive implant, which is resorted at the end of a few months. We aimed to assess the outcome of percutaneous injection of bone substitute while treating non-union of complex open tibial fractures.Materials &amp; MethodsThree cases of clinical and radiological stiff tibial non-union requiring further intervention were identified from our major trauma open fracture database. Two GA-3B cases, treated with a circular frame developed fracture-related-infection(FRI) manifesting as local cellulitis, loosened infected wires/pins with raised blood-markers, and one case of GA-3A treated with an intramedullary nail. At the time of removal of metalwork/frame, informed consent was obtained and Cerament-GTM(bone-substitute with gentamicin) was percutaneously injected through a small cortical window using a bone biopsy(Jamshedi needle). All patients were allowed to weight bear as tolerated in a well-fitting air-cast boot and using crutches. They were followed up at 6 weekly intervals with clinical assessment of their symptoms and radiographs. Fracture union was assessed using serial radiographs with healing defined as filling of fracture gap, bridging callus and clinical assessment including return to full painless weight bearing.ResultsFollow-up at 6 months showed all fractures had healed with no defect or gaps with evidence of new trabecular bone and significant resorption of Cerament-GTM at final follow-up. There was no evidence of residual infection with restoration of normal limb function. Fractures with no internal fixation showed a mild deformity that had developed during the course of the healing, presumed due to mild collapse in the absence of fixation. These were less than 10 degrees in sagittal and coronal planes and were clinically felt to be insignificant by the patients.ConclusionsCerament-G's unique combination of high dose antibiotics and hydroxy apatite matrix provided by calcium sulphate might help provide an osteoconductive environment to allow these stiff non-unions to heal. The matrix appears to provide a scaffold-like structure that allows new bone in-growth with local release of antibiotics helping reduce deep-seated infections. The final deformation at fracture site underlines the need for fixation- and it is very unlikely that this technique will work in mobile nonunions. Whilst similar fractures may heal without the use of bone substitute injections, the speed of healing in presence of significant fracture gap suggests the use of these bone substitutes did help in our cases. Further studies with a larger cohort, including RCTs, to evaluate the effectiveness of this technique compared to other methods are needed.

Impaction bone grafting as a method of choice in bone defect management in the revision hip arthroplasty: a cases series

Introduction Reconstruction of the acetabulum during revision arthroplasty is a challenging task in the setting of massive bone defects. Often the only effective method is impaction bone grafting (IBG). The purpose is to demonstrate the capabilities of the X-Change impaction bone grafting technology in replacing acetabular defects as a method of choice for revision hip arthroplasty.Materials and methods In the presented series of cases, the use (IBG) turned out to be the method of choice, allowing for high-quality reconstruction. In each presented case, revision hip arthroplasty was performed with augmentation with a reconstructive mesh or trabecular metal augment to create support and contain the defect to retain the osteoplastic material.Results During follow-up periods of 4.8 to 6.5 years there were no signs of resorption or loosening. According to the Harris hip score the results were 96, 97 and 89 points respectively.Discussion Impaction bone grafting technology is quite versatile. It can be used in various coditions of revision arthroplasty with contained defects of the acetabulum. In contrast to the use of modular revision augmentation systems and additive technologies it makes possible to achieve dense filling of the smallest defects and profile a bed congruent with the acetabular component. The use of cemented fixation makes it possible to further stabilize the impacted bone chips and use mechanotransduction mechanisms that stimulate the bone remodeling. The use of IBG has proven to be an effective technique for the reconstruction of medium-sized acetabular defects in combination with mesh and cement cup, as well as in combination with trabecular metal augments.Conclusion The use of IBG during revision hip arthroplasty can be especially effective for small acetabulum sizes. Combining IBG with trabecular metal augments significantly expands the application of this technology. The use of IBG makes it possible to create a bone reserve, which creates more favorable conditions for inevitable repeated revision interventions.

Global facial rejuvenation with hyaluronic acid: a safe set of directives to whole-approach of the aging-changes evaluated by magnetic resonance imaging

Background: Face rejuvenation with hyaluronic acid (FR-HA) through a global approach was performed in a single session, by using a safe set of directives targeted for each facial zone. Methods: FR-HA was performed with products of the QTFill Signature® range all of them with same HA-concentration and molecular-weight, with two crosslinking technologies, the own Ultra-High-Density™ crosslinking and BDDE-crosslinking with tree degrees of BDDE, resulting in high-, medium- and low-G', and 3.0% of lidocaine hydrochloride. Bolus injection with needle and retrograde-backflow injection with microcannula or needle were directed to specific facial zones. A safe FR-HA protocol based on HA-products, fat layers and vasculature, and points and techniques of injection recovered the face youthful appearance. Results: FR-HA was made for eleven facial zones, patient average of 6.95±1.30, average of 30.55±0.74 injections-points per facial-zone and of 16.80±0.83 injections-points per patient. The volume of HA injected was 49.50 ml, average of 4.50±0.37 ml per facial zone and 2.48±0.12 ml per patient. From one-month to twelve-months there was no significant differences on the face appearance and on density of the gel-diffusion displayed by MRI in T2-weighted with fat suppression on axial and coronal planes, which were endorsed by the Facelift Outcomes Evaluation questionnaire scores. Conclusions: Minimal changes on clinical outcomes and slow degradation of gel-diffusion on MRI in T2-weighted with fat suppression on axial and coronal planes from one-month to twelve-months showed that the HA-products remained stable in the injection site without evidence of significant resorption or loss of correction, indicating FR-HA efficacy and long-lasting.

The Prevalence of Root Resorption in a Sample of Orthodontic Patients Treated in Private Clinics in Sulaimani City/ A Retrospective Study

Objective: Root resorption is an inevitable consequence of orthodontic treatment. This retrospective study aimed to determine theprevalence of root resorption secondary to orthodontic treatment in private clinics in Sulaimani City, Iraq and to compare the difference in the amount of root resorption between varying teeth, regions of the mouth, and the upper and lower arches in order to lessen or eliminate unsolicited and undue impediments.&#x0D; Methods: Among the 465 cases with available data, treated in private clinics of the participating practitioners, only 92 were fullyeligible for study. Pre-operative lateral cephalograms were measured using Eastman Analysis on WebCeph. A customized frame wascreated on AutoCAD and pre and post-operative orthopantomograms were measured for root resorption only if they fitted into theframe. Intra and inter-observer reliability were performed to ensure optimal accuracy in the measurements. The millimetermeasurements of root resorption were converted into percentages to identify the prevalence of root resorption in Sulaimani City.&#x0D; Results: The root resorption in the different individual teeth resulted in a significant relationship with orthodontic treatment. Factorssuch as age, gender, and duration of treatment were not significantly associated with root resorption. The results of the upper and lower arches indicated no significant differences between the arches. The incisors showed more significant resorption when compared to canines.&#x0D; Conclusions: Orthodontic treatment affects the prevalence and severity of root resorption. Age, gender, and duration of treatment have no significant relation with apical root resorption. Different regions of the mouth encounter varying degrees of apical root resorption. Even in the anterior teeth, incisors are more prone to resorption than canines.

A Systematic Review of Technique, Satisfaction, and Complications of Acellular Dermal Matrix in Rhinoplasty.

Acellular dermal matrix (ADM) is a new dermal transplant replacement material prepared from allogeneic or xenograft skin through bioengineering technology. This is provided for patients who are unwilling to kill part of their autologous cartilage or autologous dermal tissue and require rhinoplasty and improvement in the appearance of the nasal tip. This systematic review aims to introduce the main techniques of ADM for rhinoplasty and related patient satisfaction and complications to further guide doctors. Systematic reviews were conducted in accordance with the preferred reporting items for systematic reviews and meta-analyses guidelines. The authors searched PubMed, Web of Science, Embase, and Cochrane Library using appropriate keywords. Data collected for each study included patient satisfaction and complications in addition to relevant technology. After full-text screening of inclusion and exclusion criteria, 10 studies were included, with a total of 324 patients receiving ADM with different transplantation methods. Primary rhinoplasty or secondary rhinoplasty study for dorsal ridge augmentation, smooth contour irregularities, autograft camouflage including tip grafts. The incidence of dorsal implant distortion was 0.72% in patients. The incidence of deviation was 2.17% in patients. The incidence of mild edema was 5.17% in patients. The incidence of partial resorption was 10.87% in patients. The incidence of significant resorption was 13.04% in patients. The incidence of seroma was 0.72% in patients. The incidence of partial prolapse was 0.72% in patients. The incidence of overcorrection and reoperation was 0.72% in patients. The incidence of erythema was 0.72% in patients. The incidence of undercorrection was 0.72% in patients. The incidence of infection was 0.72% in patients. The incidence of high-lying implants was 1.45% in patients. The current research results show that ADM is long-term effective in improving nasal dorsum enhancement, nasal contour deformity, and nasal tip appearance, with high patient satisfaction and low overall complication rate. Overcorrection should be considered during surgery to deal with postoperative partial absorption.

Comparative nutrient concentration and resorption dynamics in petals and leaves.

Chemical elements support various plant functions, and their reutilization is important for plant ecological adaptation. However, there is a lack of studies comparing the elemental concentration and their reutilization in floral petals and leaves of the same plant. To address this research gap, we conducted a comparative study across 38 plant species with diverse life forms in a common garden. Our investigation focused on the nutrient concentration of 10 elements in both petals and leaves and functional traits, including flower lifespan, dry mass per unit area, water concentration, and vein density. We have found that the elements of nitrogen (N), calcium (Ca), magnesium (Mg), iron (Fe), and manganese (Mn) were more abundant in leaves. In contrast, petals contained higher concentrations of phosphorus (P) and potassium (K). N, P, K, Ca, Mg, and sodium (Na) concentrations of petals were positively related to leaves. In herbaceous plants, their petals showed significant resorption of P and K, while N, P, and K were detected with significant resorption in leaves from all life forms. A positive correlation was found between the resorption of P in leaves and petals. From the perspective of the carbon economic spectrum, N and P showed a negative correlation with dry mass per unit area in leaves. Meanwhile, petal dry mass per area and floral longevity were significantly negatively correlated with P. Our findings elucidate the nutritional basis for the functional differentiation between petals and leaves.

Interpositional bone graft with cortical and cancellous calvarial bone for addressing the bone gap after reduction malarplasty: a case report

Asians typically exhibit prominent zygomas; therefore, several attempts have been made to reduce these structures to achieve a softer appearance. The intraoral approach is preferred because of its shorter surgical duration and lower invasiveness; however, it is associated with serious complications, such as nonunion. In revisional surgery, the intraoral approach poses limitations in accessing the upper part of the zygoma and the lateral orbital rim area due to its restricted operative field. Therefore, we developed an intraoral interpositional bone graft technique that enabled almost complete reconstruction. A 40-year-old woman presented with persistent depression in the left infraorbital and cheek regions after two revision operations after reduction malarplasty. Based on computed tomography (CT) scan findings, reconstruction using bone grafts was planned. Calvarial bone was harvested and divided into cortical and cancellous parts. The cortical bone was sculpted into an L-shape and inserted into the gap between the maxilla and the lower zygoma body. The hard-to-reach lateral orbital rim area was filled with cancellous bone without fixation. Follow-up CT scans showed that the cortical bone grafts were well-maintained and stabilized with titanium plates, while the cancellous bone had undergone significant resorption and was replaced by new bone, indicative of successful natural healing.

Allograft bone vs. bioactive glass in rehabilitation of canal wall-down surgery

Canal wall-down (CWD) mastoidectomy creates a radical cavity that modifies the anatomy and physiology of the middle ear, thus preventing it from being self-cleaning and causing epidermal stagnation in the posterior cavities. Canal wall-down tympanomastoidectomy with reconstruction (CWDTwR) can obliterate such radical cavities. The main objective of this study was to compare postoperative results after CWDTwR by using either bone allografts or 45S5 bioactive glass as a filling tissue with an 18-month follow-up. This was a single-center observational trial including all patients undergoing CWDTwR. Patients were divided into two groups according to the filling material used: allograft bone (AB group) or 45S5 bioactive glass (BG group). Clinical monitoring was performed regularly, with control imaging performed at 18 months (CT scan and DW MRI). The two groups were compared with the t test for quantitative variables and the chi square test for qualitative variables (no revision surgery, audiometric results, complications, mastoid obliteration volume). Thirty-two patients underwent CWDTwR between October 2015 and 2018. The mean age was 48 years, and 71.9% (23/32) were men. A total of 46.9% (15/32) of the patients had undergone at least 3 middle-ear surgeries prior to CWDTwR. The most frequent preoperative symptom was otorrhea (100.0%, 32/32), and only 12.5% (4/32) experienced dizziness. Fifteen and 17 patients underwent surgery with bone allografts and 45S5 bioactive glass, respectively. At 18 months post-operation, 53.3% of the patients (8/15) in the AB group presented with recurrent otorrhea versus 5.9% (1/17) of patients in the BG group (p = 0.005). Seventy-eight percent (7/9) of symptomatic patients had undergone revision surgery at 18 months postoperation: 40.0% (6/15) in the AB group and 5.9% (1/17) in the BG group (p = 0.033). One patient’s surgery was cancelled due to the COVID-19 pandemic, and one patient refused surgery. The effects of CWDTwR with bone allografts are disappointing in early follow-up, with significant resorption leading to a 40.0% revision surgery rate. 45S5 BG is a simple solution, with preliminary results that are superior to those of AB. However, prospective controlled studies with longer follow-up times are needed to evaluate the value of BG versus other synthetic materials (such as hydroxyapatite) in surgical management of CWDTwR.Trial registration: retrospectively registered.

The effect of bony obliteration on quality of life after tympano-mastoidectomy surgery: A prospective observational controlled cohort study.

The study's primary objective was to compare the quality of life (QoL) and external auditory canal (EAC) hygiene among patients who underwent bony mastoid obliteration or meatoplasty after canal wall down (CWD) mastoidectomy. A prospective, observational, controlled cohort study was conducted at our tertiary referral university hospital. Twenty-eight patients older than 16 years of age with chronic otitis media who underwent CWD mastoidectomy were included. Two cohorts were followed: CWD mastoidectomy followed by mastoid obliteration (Group 1, n = 14) and CWD mastoidectomy followed by meatoplasty (Group 2, n = 14). The main outcome measures of total COMBI score (postoperative 6-month QoL) and EAC hygiene were compared between the groups. The average age of the patients was 36.14 (12. 22) years; 15 (53.6%) were female and 13 (46.4%) were male. There were no differences in demographic variables, preoperative findings, or COMQ-12 (preoperative QoL) scores between groups. The average COMBI score of Group 1 (49.0 [8.66]) was not significantly different from Group 2 (46.79 [7.76]) (p = .482). Poor EAC hygiene was observed in eight (57.1%) patients in Group 2 and three (21.4%) patients in Group 1 (p = .06). In Group 1, no resorption of graft material was observed in 10 (71.4%) patients, minor resorption was observed in three (21.4%) patients, and significant resorption was observed in one (7.1%) patient. There were no significant differences in audiological findings between groups (p > .05). There were no significant differences regarding short-term postoperative QoL, EAC hygiene, or hearing outcomes between patients who underwent bony mastoid obliteration or meatoplasty after CWD mastoidectomy. 1b (individual prospective cohort study).

Comparative Evaluation of Extrusion of Apical Debris in Primary Maxillary Anterior Teeth Using Two Different Rotary Systems and Hand Files: An In Vitro Study.

Successful outcome of pulp therapy depends on good chemomechanical preparation of the canals. This is completed with the help of various upcoming rotary and hand files. However, during this preparation, there might be an apical extrusion of the debris which may result in postoperative complications. The aim of this study was to evaluate and compare the number of debris apically extruded during canal preparation using two different pediatric rotary file systems and conventional hand file systems in primary teeth. 60 primary maxillary central incisors that were extracted due to trauma or untreated dental caries with no signs of resorption were taken. Canal preparation was executed using three different file systems: Group A: Group A hand K file system, Group B Kedo S Plus, Group C Kedo SG Blue. For each of these files using the Myers and Montgomery model, the pre- and post-weight of the eppendorf tube was assessed to quantify the number of apical debris. The maximum extrusion of apical debris was noticed with the Hand K-file system. The least debris was noticed in the Kedo S Plus file system. Statistical analysis revealed that there were highly significant differences in apical extrusion and debris when comparing hand files and rotary files and also between the two rotary files used. Apical debris collection is an unavoidable outcome of canal instrumentation. Among the file systems compared, rotary files had lesser extrusion when compared to hand files. Among the rotary files, Kedo S plus showed normal extrusion compared to SG Blue.

Using Zircons to Disentangle Back-Veining and Hybridization of Diorite Dykes: an Example From the Gangdese Arc, Tibet

AbstractThermo-chemical modeling and chemical data suggest that the genesis of arc melts commonly involves re-melting of older intrusions, triggered by the injection of mantle-derived melts, followed by magma mixing. Remelting and mixing may lead to complex zircon populations, which can be used to gain insights into the conditions of mixing. This paper investigates a case where such processes can be studied through the compositional and thermal record provided by zircons preserved in a diorite dyke swarm that remelted host rock tonalites in the Gangdese Batholith in Tibet. Autocrystic zircons from the diorite yield consistent ages of 46 to 47 Ma even though they can be altered, having highly enriched trace elements, reaching ~1 wt % in Fe, Ca, Y, U, Th, and anomalously high values of LREE and Ti. Granitic magmas derived from the tonalite, back-veined the dykes and mixed with the dioritic mush, transferring small quantities of 77–79 Ma zircon xenocrysts. The xenocrysts are euhedral with little evidence for resorption, indicating that they were apparently stable during the process of tonalite anatexis and transfer to the diorite magma. This requires that: (i) tonalite melting occurred at low temperatures with minimal zircon dissolution, and (ii) the diorite either cooled rapidly before significant resorption of the grains or was already saturated in zircon when mixing occurred. Zircon saturation temperatures of the diorite are relatively low, indicating that xenocrystic zircons were transferred to a highly crystalline dioritic mush. This requires either liquefaction by injection of the back-veining felsic magma to allow for mixing, or pervasive throughflow of the diorite mush by the felsic magma leaving behind zircon xenocrysts. The findings suggest that the dykes triggered low-T, water-fluxed melting of the host tonalite and that these anatectic melts invaded the diorite mush initially through the interstices leading to mixing. This may have caused the breakdown of the crystalline framework leading to liquefaction and renewed magma flow. Dyking and assimilation of wall-rock through back-veining as recorded in these rocks could be common in transcrustal arcs. However, this process could be hidden due to a combination of the similarity in the isotopic and chemical nature of arc rocks and resorption of zircon xenocrysts during mixing. This process may explain some complex chemistry of arc magmatic rocks and their minerals that are not easily explained by endmember models, such as pure re-melting of older arc rocks or fractional crystallization of mantle-derived melts.

Evaluation of Alveolar Bone Dimensions and Root Positioning of Anterior Teeth in the Maxilla.

Buccal bone walls present significant resorption after tooth extraction, possibly related to the smaller bone thickness, length, and the sagittal position of the root, as well as the bone morphology. The goal of the present study was to measure the thickness of the cortical bone of the vestibular and palatal walls in the anterior maxilla by means of CBCT images. Measurements were taken from CBCT scans of 300 maxillary anterior teeth from 50 patients (25 women, 25 men) aged 18 to 30 years. The parameters evaluated included the thickness of the buccal and palatal cortical bone in the cervical, apical, and middle thirds of the root, as well as six specific angular measurements from each tooth. The lateral incisors showed a significant difference in thickness between each of the buccal and palatal thirds, and measurements were also significantly smaller than the central and canine incisors. Bone anatomy is tooth-and location-specific, and thus the sagittal root position within the alveolus influences the regional bone morphology and may explain the gingival zenith position in the anterior maxilla. These specific buccal and palatal anatomic parameters should be carefully taken into consideration for surgical planning and intervention in the esthetic area.

Mandibular morphological analysis of rats with osteoporosis and periradicular lesions

The aim of the study was to perform a morphological analysis of the effects of osteoporosis on the periodontal ligament of rats with periradicular injury. Adult rats (n = 24), of the Wistar lineage, 3 months old, were included in the study. Twelve animals were ovariectomized (group OVX) and 12 were operated by simulation (group C). One hundred and twenty days after surgery, all animals were anesthetized, and in each animal, periradicular lesion was developed in the mandibular left first molar, by making a coronal opening in the mesial fossa on the occlusal surface until the pulp was exposed. At the end of each experimental time interval (21 and 40 days after the lesion developed), the animals were sacrificed, and blood was collected to confirm the effects of castration by serum estrogen measurement. The jaws were removed and prepared for quantitative analysis of the periodontal ligament thickness, by using an optical microscope. Comparative analysis of the data was performed using the non-parametric Kruskal-Wallis and Dunn Multiple Comparison tests. A reduction in serum estrogen levels was observed in the OVX groups (p &lt;0.01), and a significant increase in the periodontal ligament thickness in Group C 21, when compared with Group OVX 40 days (p &lt;0.01), and Group C 40 compared with Group OVX 40 days (p&lt;0.01). In all samples with osteoporosis, there were signs of resorption in the alveolar bone, and significant periodontal ligament thickening in animals with longer exposure to the disease.

Circadian Rhythm Disorders Aggravate Periodontitis by Modulating BMAL1

Circadian rhythms regulate the body's homeostasis through the temporal control of tissue-specific circadian rhythm control genes. Circadian rhythm disorders (CRD) affect the expression levels of circadian rhythms-associated genes in brain and muscle aryl hydrocarbon receptor nuclear translocator-like-1(BMAL1), which is thought to contribute to metabolic disorders and an altered immune system. However, the relationship between CRD and the development of periodontitis was poorly reported. Therefore, this study aimed to investigate the role played by BMAL1 in periodontitis. We used a modified multi-platform approach (MMPM) to induce circadian rhythm disturbances in rats to investigate the role of BMAL1 in periodontitis. Our results showed significant downregulation of BMAL1 in the CRD with periodontitis group, significant resorption of alveolar bone, increased osteoclast differentiation, and upregulation of the inflammatory signaling molecule NF-κB. In addition, apoptosis and oxidative stress levels were increased in periodontal tissues. Collectively, our study suggests that BMAL1 is a key regulator in periodontitis exacerbated by CRD and that CRD may lead to the downregulation of BMAL1, thereby exacerbating oxidative stress and apoptosis in periodontal tissues. Our study found that BMAL1 may be associated with the progression of periodontitis and provides a new perspective on the treatment of periodontitis.

The Preventive Effect of A Magnetic Nanoparticle-Modified Root Canal Sealer on Persistent Apical Periodontitis.

Persistent apical periodontitis is a critical challenge for endodontists. Developing root canal filling materials with continuous antibacterial effects and tightly sealed root canals are essential strategies to avoid the failure of root canal therapy and prevent persistent apical periodontitis. We modified the EndoREZ root canal sealer with the antibacterial material dimethylaminododecyl methacrylate (DMADDM) and magnetic nanoparticles (MNPs). The mechanical properties of the modified root canal sealer were tested. The biocompatibility of this sealer was verified in vitro and in vivo. Multispecies biofilms were constructed to assess the antibacterial effects of the modified root canal sealer. We applied magnetic fields and examined the extent of root canal sealer penetration in vitro and in vivo. The results showed that EndoREZ sealer containing 2.5% DMADDM and 1% MNP had biological safety and apical sealing ability. In addition, the modified sealer could increase the sealer penetration range and exert significant antibacterial effects on multispecies biofilms under an external magnetic field. According to the in vivo study, the apices of the root canals with the sealer containing 2.5% DMADDM and 1% MNP showed no significant resorption and exhibited only a slight increase in the periodontal ligament space, with a good inhibitory effect on persistent apical periodontitis.