Comparison of initial stability of mandibular first molar repaired with different threaded implants under immediate loading / 中国组织工程研究

BACKGROUND:The threaded conical implant has a good ability to control micro movements and is conducive to immediate loading.However,the effects of double-threaded conical cylindrical implants and conical cylindrical implants on stress distribution and initial stability of implant-bone interface after immediate loading have not been reported. OBJECTIVE:To investigate the impact of double-threaded conical cylindrical implants and conical cylindrical implants on the biological distribution of the implant and the surrounding bone interface during immediate loading in the mandibular molar region. METHODS:(1)Three-dimensional finite element analysis:Conical beam CT scans of the mandible and first molar of a volunteer were used to develop a basal model of the mandible.The double-threaded conical cylindrical implants and conical cylindrical implants were assembled with the mandibular models,and an immediate-load(or delayed implantation)implant model(a total of four models)for the first mandibular molar was established.Loads in four directions(100 N):axial,lingual and buccal 45°,mesial and distal,and buccal and lingual,were applied to the central fossa of each model's crown.Three-dimensional finite element method was used to analyze the implant displacement and the stress distribution at the implant-bone interface.(2)In vitro experiment:With the assistance of the oral implant robot,the double-threaded conical cylindrical implants and conical cylindrical implants were implanted on the same artificial bone pieces,separately,and the immediate load model of immediate implant implantation(or delayed implantation)was established in vitro(a total of four groups of models).Osstell resonance frequency analyzer and SmartPeg sensor were used to measure the implant stability coefficient in four vertical directions:front,rear,left,and right measurements,evaluate the initial stability,and verify the finite element analysis results. RESULTS AND CONCLUSION:(1)The displacement difference between double-threaded conical cylindrical implants and conical cylindrical implants was small when the immediate loading of delayed implantation was applied,but the maximum stress value of conical cylindrical implant-bone interface was greater than that of double-threaded conical cylindrical implant-bone interface.When the immediate loading of immediate implantation was applied,the maximum stress value and the maximum displacement of bone around the implant appeared when the load was applied in mesiodistal direction.The stress value of the conical cylindrical implant reached 298.84 MPa and the maximum displacement was 0.31 mm,both of which were larger than that of the double-threaded conical cylindrical implant.(2)The results of in vitro experiments showed that the stability coefficient of the double-threaded conical cylindrical implant was greater than that of the conical cylindrical implant.(3)Compared with the conical cylindrical implant,the double-threaded conical cylindrical implant has higher initial stability under immediate loading,suggesting that the use of double-threaded conical cylindrical implant should be given priority in clinical immediate loading.

Research progress of exosome microneedle drug delivery system / 中国药房

Microneedles can penetrate the skin barrier to deliver drugs without touching the nociceptive nerves， to effectively increase the efficiency of transdermal drug delivery and improve patient compliance. Exosomes have multiple physiological functions and good biocompatibility， and are natural nanoscale drug carriers. This paper reviews the pathways and advantages of exosomes combined with microneedles for the treatment of diseases， and describes the current research status of exosome microneedle drug delivery system in various diseases. Exosome microneedles can be divided into two categories： （1） exosomes as therapeutic agents， their unique physiological origin can effectively avoid the toxicity and immunogenicity of conventional drugs and other problems； combined with microneedles directly in the specific medication site can greatly improve the metabolic consumption of oral drug delivery and patient compliance of injection drug delivery. （2） Exosomes as drug carriers， their natural vesicle structure and endogenous characteristics can protect the metabolism of foreign drugs in the body and enhance the targeting； combined with microneedles can effectively solve the problem of transdermal delivery of drugs with high efficacy but poor stability. Exosome microneedle drug delivery system is still in the laboratory stage， but it has shown great development prospects in repairing spinal cord injury， promoting diabetic ulcer wound healing， germinating， intervening myocardial infraction， relieving chronic pain and other diseases.

Effect of loading protocol on peri-implant marginal bone loss: randomized clinical trial / Efeito do protocolo de carregamento na perda óssea marginal peri-implantar: ensaio clínico randomizado

Objective: This clinical study was conducted to evaluate the effect of loading protocol using hybrid ceramic resinous material on marginal bone loss. Material and Methods: This study was conducted in the fixed prosthodontics department, at Ain Shams University on 30 titanium endosseous tapered threaded implants which were placed in 30 patients in the upper premolar area. Patients were divided randomly according to the loading protocol into 3 groups (10 patients each): Group I (IFLV): patients received CAD/CAM polymer infiltrated ceramic (VITA-ENAMIC) crowns (immediate functional loading), Group II (IFLP): patients received CAD/CAM PMMA crowns (in occlusion for 3 months) followed by CAD/CAM polymer infiltrated ceramic (VITA-ENAMIC) crowns (functional loading), and Group III (INFLP): patients received CAD/CAM PMMA crowns (out of occlusion for 3 months) followed by CAD/CAM VITA-ENAMIC crowns (functional loading). Results: After three months; the highest value of marginal bone loss (mm) was found in IFLV, followed by IFLP, while the lowest value was found in INFLP. After six months, the highest value was found in IFLP, followed by IFLV, while the lowest value was found in INFLP. Also, after twelve months, the highest value was found in IFLV, followed by IFLP, while the lowest value was found in INFLP. Marginal bone loss values were within the accepted values for clinical success for all the tested groups. Conclusion: Immediate non-functional loading provided more acceptable outcomes than immediate functional loading. Also, immediately functional and non-functional implant loading using hybrid ceramic as permanent material has shown promising results with proper patient selection (AU)

Objetivo: Este estudo clínico foi realizado para avaliar o efeito do protocolo de carregamento utilizando material resinoso cerâmico híbrido na perda óssea marginal. Material e Métodos: Este estudo foi realizado no departamento de prótese fixa da Universidade Ain Shams em 30 implantes endósseos cônicos de titânio que foram instalados em 30 pacientes na região de pré-molares superiores. Os pacientes foram divididos aleatoriamente de acordo com o protocolo de carregamento em 3 grupos (10 pacientes cada): Grupo I (IFLV): os pacientes receberam coroas usinadas em CAD/CAM de cerâmica infiltrada com polímero (VITA-ENAMIC) (carga imediata), Grupo II (IFLP): os pacientes receberam coroas usinadas em CAD/CAM de PMMA (em oclusão por 3 meses) seguidas por coroas de cerâmica infiltrada com polímero (VITA-ENAMIC) (carga funcional), e Grupo III (INFLP): os pacientes receberam coroas usinadas em CAD/CAM de PMMA (infraoclusão por 3 meses) seguido de coroas de VITA-ENAMIC (carga funcional). Resultados: Após três meses; o maior valor de perda óssea marginal (mm) foi encontrado no IFLV, seguido pelo IFLP, enquanto o menor valor foi encontrado no INFLP. Após seis meses, o maior valor foi encontrado no IFLP, seguido do IFLV, enquanto o menor valor foi encontrado no INFLP. Além disso, após doze meses, o maior valor foi encontrado no IFLV, seguido pelo IFLP, enquanto o menor valor foi encontrado no INFLP. Os valores de perda óssea marginal estavam todos dentro de valores aceitáveis para sucesso clínico para todos os grupos testados. Conclusão: A carga funcional não imediata proporcionou resultados mais aceitáveis do que a carga imediata. Além disso, o carregamento funcional imediato e não imediato de implantes utilizando coroas finais de cerâmica híbrida mostrou resultados promissores com a seleção adequada dos pacientes.(AU)

Efectos de la microvibración y estrógeno en la remodelación ósea: revisión sistemática / Effects of micro-vibration and estrogen on bone: a systematic review

Introducción: la pérdida de hueso es un suceso que afecta a la totalidad del esqueleto. Así, las alteraciones musculoesqueléticas afectan a millones de personas en todo el mundo y están entre las causas más comunes de dolor crónico. Objetivo: conocer los efectos de la microvibración y estrógeno en el remodelado óseo. Material y métodos: se realizó una revisión sistemática, se buscó en siete bases de datos, se incluyeron estudios clínicos controlados realizados con ratas o ratones en el periodo de publicación del 2004 al 2022. La calidad de la evidencia sintetizada se evaluó con la escala de Jadad. Resultados: se identificaron quince artículos como estudios primarios. La microvibración reportó cambios in vivo/in vitro totalmente dependientes del estímulo que conlleva incremento de la cortical externa. A su vez, con la administración de estrógeno se reportaron efectos, específicamente, en el hueso trabecular y en el periostio, así como colágeno inmaduro que indican un recambio óseo. Conclusión: tanto la microvibración como la administración de estrógeno coadyuvan a la remodelación del tejido óseo y son aprovechables como tratamiento en el momento que exista un problema de pérdida ósea (AU)

Introduction: Bone loss is an event that affects the entire skeleton. Thus, musculoskeletal disorders affect millions of people worldwide and are among the most common causes of chronic pain. Objective: to know the effects of micro-vibration and estrogen on bone remodelling. Material and methods: a systematic review was carried out; seven databases were searched; Controlled clinical studies conducted with rats or mice in the publication period from 2004 to 2022 were included. The quality of the synthesized evidence was assessed using the Jadad scale. Results: fifteen articles were identified as primary studies. Micro vibration reported in vivo/in vitro changes dependent on the stimulus that entails an increase in the outer cortex. In turn, with the administration of estrogen, effects were reported, specifically in the trabecular bone and in the periosteum, as well as immature collagen that indicates bone turnover. Conclusion: both micro-vibration and the administration of estrogen contribute to the remodelling of bone tissue and are usable as a treatment for bone loss (AU)

Three-dimensional finite element analysis of the influence of implant site and axial direction on the immediate weight bearing stress of central incisors in different alveolar fossa shapes / 口腔医学

Objective@#To analyze and investigate the effects of implant location and axial direction on the stress distribution of implants, abutments, central screws, and crowns during immediate loading of maxillary mesial incisors with different alveolar fossa morphology based on three-dimensional finite element method.@*Methods@#Referring to the oral CBCT images of a healthy adult, a three-dimensional finite element model was established for immediate implant loading of maxillary central incisors with three alveolar fossa morphs: labial, intermediate, and palatal; different implant sites(apical site, palatal/labial site) and axes(tooth long axis, alveolar bone long axis) were simulated; the established model was loaded with a force of 100 N. ANSYS software was applied to analyze the stress values of the implants, abutments, central screwss, and crownss. @*Results@#The 3D finite element models of 12 maxillary central incisors with different alveolar sockets were successfully established;the implants and their superstructures were least stressed when the maxillary central incisors with partial labial and partial palatal shape were placed along the long axis of the alveolar bone in the palatal/labial position for immediate implant loading;the implants and their superstructures were least stressed when the maxillary central incisors with central shape were placed along the long axis of the tooth in the palatal position for immediate implant loading. The implant and its superstructure were subjected to the least stress when the implant was placed along the long axis of the tooth in the immediate loading position. @*Conclusion@#The bio-mechanical characteristics of the implant and its superstructure are influenced by the different socket morphology, implantation sites and axes. Therefore, in clinical practice, different implantation axes and implantation sites should be developed for different socket morphs.

Research Progress on Biomechanics and Mechanobiology of Articular Cartilage in 2022 / 医用生物力学

As a kind of elastic load-bearing connective tissues on bone surface in dynamic joints, articular cartilage can provide low wear lubrication, shock absorption, load transfer and other supporting functions, and has hierarchical fiber composite structures and excellent mechanical properties. As an avascular and aneural tissue,the degenerated articular cartilage lacks the capability of self-healing after damage. The high incidence of arthritisis still a hot spot in basic and clinical researches. Articular cartilage is a mechanical sensitive tissue, andmechanical environment will affect the development of tissues in different directions. Extensive researches onbiomechanics and mechanobiology of articular cartilage were conducted in 2022. Many studies on morphology, function and mechanical state of cartilage,as well as mechanical state of cartilage under different conditions were reported. Some cartilage-related loading devices were designed at animal, tissue and cell levels. Researches onthe repair of cartilage degeneration and injury under mechanical loads were carried out in vitro and in vivo, andsome important repair method and means were obtained. The biomechanical and mechanobiology research on articular cartilage is the basis of arthritis, cartilage defect and repair. The influence of quantitative mechanical under 4 conditions on the repair of articular cartilage injury needs further study in vivo and in vitro

Preparation and in vitro evaluation of prostate cancer exosomes containing melittin / 中国药理学通报

Aim To prepare prostate cancer exosomes containing melittin and observe their uptake by prostate cancer cells. Methods Cells treated with starvation for different time were screened for exosome extraction. Exosomes from PC-3 cells were extracted by ultracentrifugation, and the extracted particles were examined by transmission electron microscopy, nanoparticle tracking analyzer(NTA), and Western blot. Melittin exosome system was prepared by repeated freeze-thaw method, incubation at room temperature as well as electroporation, and the size of encapsulation efficiency was measured by centrifugation. A high-performance liquid chromatography(HPLC)method was applied to assay the content of melittin exosomes(exo-mel). Fluorescence inverted microscopy was employed to evaluate the uptake of melittin exosomes by PC-3 cells, DU145 cells as well as LNCaP cells. Results The results of starvation treatment showed that 24 h starvation treatment was the optimal time point. TEM results showed that the exosomes were round or oval in shape with a distinct membranous structure, and the diameter was around 100 nm. The reagent protein concentration for NTA analysis of exosomes was 0.222 g·L-1. The results of Western blot for the marker proteins of exosomes showed that Alix and CD63 were positively expressed, which indicated that the exosomes could be obtained by starvation culture of PC-3 cells and ultracentrifugation. The results of entrapment efficiency showed that the entrapment efficiency of electroporation method was 17.51% ± 2.39%, that of repeated freeze-thaw method was 11.46% ± 1.02%, and that of room temperature incubation method was 3.93% ± 2.44%. The encapsulation efficiency of electroporation was the highest with significant difference(P<0.05). The uptake assay showed that PC-3 cells could efficiently take up exo-mel in a time-dependent manner, and DU145 cells and LNCaP cells also could take up exo-mel over time. Conclusions Exosomes can be accessed by starvation treatment and high-speed centrifugation, and the prostate cancer melittin exosome system prepared by electroporation method could be taken up by prostate cancer cells.

Research progress of bio-metal organic frameworks in drug delivery system / 中国药科大学学报

@#In recent years, bio-metal organic frameworks (Bio-MOFs) synthesized with biocompatible ligands have been widely investigated as a potential drug delivery carrier due to their large specific surface area and porosity, rich host-guest intermolecular interactions, and good biocompatibility.In this review, we summarized the design methods of Bio-MOFs including structural and toxic factors, as well as a variety of drug loading methods including click chemistry, with particular focus on recent research advances in Bio-MOFs for pulmonary drug delivery systems, improving pharmaceutical properties of drugs, sustained and controlled drug release, stimulation response and targeted drug delivery systems.Finally, we summarized the bottlenecks that constrain the development of Bio-MOFs in clinical studies of actual pharmaceutical formulations and their future directions for approved formulations, aiming to provide some theoretical reference for promoting the application of Bio-MOFs in drug delivery systems.

Progress of research on chitosan-based microspheres in oral tissue lesions / 口腔医学

@#Chitosan-based microspheres use chitosan as the main material to obtain particles with special structures through microsphere processing technology. They have the ability of slow and controlled release of drugs and the role of scaffolding, which have great application prospect in stomatology, but the application of chitosan-based microspheres is still in the research stage and has not yet been applied in clinical practice. This article reviews progress of domestic and foreign research on chitosan-based microspheres, in aspects of treatment of oral and jawbone tissue defects, periodontal diseases, dental pulp diseases and nerve tissue injury, in order to provide reference for follow-up research.

Research progress of exosome drug loading system / 中国药房

Exosome is a kind of vesicle secreted by a variety of cells with lipid bilayer membrane structure， which has good biocompatibility， high targeting and high stability， and is a natural nanoscale drug carrier with great development potential in drug delivery system. In this paper， exosomes and their properties， exosome drug delivery pathways and methods， the design strategy of engineered exosome drug delivery systems for targeted disease therapy， and the application of exosome drug delivery systems in the treatment of a variety of diseases were reviewed. Exosome drug delivery pathways could be divided into two categories： exogenous and endogenous. Common exosome drug delivery methods included electroporation， co-incubation， and ultrasound. Engineered exosome drug delivery system can further improve drug loading and enhance drug targeting. The main way of engineering is to modify exosome surface through genetic engineering technology， physical modification， chemical modification， etc. Exosome drug delivery system provides a new idea for targeted therapy of arthritis， tumor， brain and other diseases.

Carga inmediata de implantes extra cortos en sectores posteriores. Estudios retrospective con tres modelos de carga: 24, 48 hs y 7 días / Immediate loading of extra short implants in posterior sectors. Retrospective study with three loading models: 24 hs, 48 hs and 7 days

Los implantes extra-cortos son cada vez más utili-zados en la práctica clínica diaria. La utilización de estos implantes con carga inmediata supone un reto añadido. Clásicamente se ha postulado que la carga inmediata debe realizarse después de 24 horas de la cirugía. En la siguiente serie de casos analizamos diferentes tiempos a la hora de realizar la carga in-mediata y su posible repercusión. Fueron recolec-tados de forma retrospectiva datos sobre casos de implantes extra-cortos (5,5 y 6,5 mm) en los que fue realizada una carga inmediata en sectores poste-riores. El implante fue la unidad de análisis para la estadística descriptiva en cuanto a la localización, dimensiones del implante, y mediciones radiográ-ficas. El paciente fue la unidad de medida para el análisis de la edad, sexo y la historia clínica. La prin-cipal variable estudiada fue la supervivencia de los implantes extra-cortos con carga inmediata en tres períodos de tiempo determinados: 24 hs, 48 hs y 7 días y como variables secundarias se han estudiado, la estabilidad del hueso crestal en general y en los tres períodos de carga anteriormente mencionados, las complicaciones protésicas y la supervivencia de las prótesis. Fueron reclutados 74 pacientes en los que se insertaron 146 implantes que cumplieron con los criterios de inclusión. Todos los implantes fueron cargados mediante carga inmediata en tres perío-dos determinados de tiempo: 24 hs (40 implantes), 48 hs (42 implantes) y 7 días (42 implantes). Todos los implantes fueron ferulizados a otros implantes ge-nerándose puentes de dos o más unidades, con di-ferente longitud. En el grupo de implantes con carga inmediata en 24 hs la media de la pérdida ósea distal de todos los implantes fue de 0,21 mm (+/-0,84) y la media de la pérdida ósea mesial en este grupo fue de 0,33 mm (+/- 0,53). En el grupo de carga inmediata en 48 hs, la media de la pérdida ósea distal de todos los implantes fue de 0,20 mm (+/- 0,82) y la media de la pérdida ósea mesial fue de 0,22 mm (+/- 0,81). En el grupo de carga de 7 días, la pérdida ósea me-sial del grupo fue de 0,28 mm (+/- 0,51) y la media de la pérdida ósea distal fue de 0,17 mm (+/- 0,81). Cuando comparamos las medias de pérdida ósea me-sial y distal entre los tres grupos, no se observaron diferencias estadísticamente significativas (mesial p=0,062, distal p=0,067). En conclusión, no se obser-varon diferencias significativas en la pérdida ósea crestal ni en la supervivencia de los implantes cortos entre los 3 tiempos estudiados de aplicación de car-ga inmediata. Por ello, utilizar cualquiera de los tres protocolos puede ser adecuado, mientras se realice un correcto análisis de la situación clínica de cada paciente (AU)

Extra-short implants are increasingly used in daily clinical practice. The use of these implants with immediate loading poses an added challenge. Classically it has been postulated that immediate loading should be performed 24 hrs after surgery. In the following case series, we analyze different times of immediate loading and their possible repercussions. We retrospectively collected data on cases of extra-short implants (5.5 and 6.5 mm) in which immediate loading was performed in posterior sectors. The implant was the unit of analysis for descriptive statistics in terms of location, implant dimensions, and radiographic measurements. The patient was the unit of measurement for the analysis of age, sex and medical history. The main variable studied was the survival of immediately loaded extra-short implants in three specific time periods: 24 hrs, 48 hrs and 7 days. Secondary variables studied were crestal bone stability in general and in the three loading periods mentioned above, prosthetic complications and prosthesis survival. Seventy-four patients were recruited and 146 implants that met the inclusion criteria were inserted. All implants were loaded by immediate loading in three specific time periods: 24 hrs (40 implants), 48 hrs (42 implants) and 7 days (42 implants). All implants were splinted to other implants generating bridges of two or more units, with different lengths. In the 24-hr immediate loading group the mean distal bone loss of all implants was 0.21 mm (+/- 0.84) and the mean mesial bone loss in this group was 0.33 mm (+/- 0.53). In the 48-hr immediate loading group, the mean distal bone loss for all implants was 0.20 mm (+/- 0.82) and the mean mesial bone loss was 0,22 mm (+/- 0,81). In the 7-day loading group, the mesial bone loss of the group was 0.28 mm (+/- 0.51) and the mean distal bone loss was 0.17 mm (+/- 0.81). When we compared the mean mesial and distal bone loss between the three groups there were no statistically significant differences (mesial p=0.062, distal p=0.067). In conclusion, no significant differences were observed in crestal bone loss or in the survival of short implants between the 3 immediate load application times studied. Therefore, using any of the three protocols can be appropriate, as long as a correct analysis of the clinical situation of each patient is performed (AU)

Fracture resistance of pressed ZLS crowns versus pressed LD crowns under thermo-mechanical cycling

Resumo Este estudo teve como objetivo avaliar a resistência à fractura do silicato de lítio reforçado com zircônio todo o material cerâmico "Celtra Press" em comparação com um "IPS e-max Press" em condições orais simuladas. Quatorze coroas cerâmicas foram fabricadas em moldes epóxi que foram duplicados a partir de moldes principais de aço inoxidável e divididos em dois grupos iguais (n=7) de acordo com o material de construção; Grupo A: Coroas fabricadas com material IPS e-max Press e Grupo B: Coroas fabricadas com material Celtra Press. As coroas foram então cimentadas nos seus moldes correspondentes com um cimento de resina auto-adesivo e submetidas a ciclos térmicos e cargas cíclicas. Em seguida, foram carregadas para fraturar numa máquina universal de ensaios. Os resultados foram tabulados e analisados estatisticamente utilizando os testes Kolmogorov-Smirnov e Shapiro-Wilk. O teste t de Student usado para comparar os valores médios. O nível de significância foi fixado em P ≤ 0,05 e intervalo de confiança de 95%. A análise estatística foi realizada utilizando o software Graph Pad Instat (Graph Pad, Inc.) para Windows. Os valores médios ± SD da resistência à fractura foram registados para o grupo Disilicate de lítio (1706,01 ±154,32 N) enquanto que os valores médios ± SD registados com o grupo celtra foram (1550,67±196,71 N). As coroas cerâmicas de silicato de lítio reforçado com zircónio produziram valores de resistência à fractura comparáveis aos das coroas cerâmicas de dissilicato de lítio e ambos os materiais testados estão dentro dos valores clinicamente aceitáveis na área posterior.

Abstract The aim of this study was conducted to assess the fracture resistance of zirconia reinforced lithium silicate all ceramic material "Celtra Press" compared to lithium disilicate one "IPS e-max Press" under simulated oral conditions. Fourteen ceramic crowns were fabricated on epoxy dies which were duplicated from stainless steel master die and divided into two equal groups (n=7) according to the material of construction; Group A: Crowns fabricated with IPS e-max Press material and Group B: Crowns fabricated with Celtra Press material. The crowns were then cemented onto their corresponding dies with a self-adhesive resin cement and subjected to thermocycling and cyclic loading. Then they were loaded to fractur in a universal testing machine. The results were tabulated and statistically analyzed using Kolmogorov-Smirnov and Shapiro-Wilk tests. Student t-test used to compare mean values. The significance level was set at P ≤ 0.05 and 95% Confidence interval. Statistical analysis was performed using Graph Pad Instat (Graph Pad, Inc.) software for windows. The mean ± SD values of fracture resistance were recorded for lithium Disilicate group (1706.01 ±154.32 N) meanwhile the mean ± SD value recorded with celtra group were (1550.67±196.71 N). Zirconia reinforced lithium silicate ceramic crowns produced comparable fracture resistance values to lithium disilicate ceramic crowns and both tested materials are within the clinically acceptable values in the posterior area.

Influence of abutment angulation on implant failure in immediately placed and restored implants in the esthetic zone: a randomized clinical trial

Background: Tooth extraction socket in the aesthetic area is a major indication for immediate implant placement greatly improving patient satisfaction and preserving the alveolar ridge. However, the effect of non-axial force on the peri-implant bone with subsequent early implant failure remains unclear. Objective:Evaluate the prognosis of tilted implants immediately placed and restored with angled abutments in comparison to straight implants restored with straight abutments in the esthetic area (anterior or premolars) using computer-aided surgical guides. Material and methods: Badly decayed non-restorable teeth in the aesthetic zone (anterior or premolars) were extracted atraumatically. Immediately after guided implant insertion, the abutments were adjusted and placed according to the allocation group (0, 15, or 25-degree angle) then a temporary crown was performed out of occlusion in centric and eccentric relation. Early implant failure was assessed at three and six months. Results:There was no statistically significant difference between the two groups (P=0.305). Straight and angled abutment groups showed 6 (14.3%) and 8 (20%) failed cases, respectively. The post-hoc subgroup analysis showed no statistically significant difference between angle 15 and angle 25 degree groups where (P=0.686) or between Anterior and Premolar groups (P=0.853). Conclusion: There was no statistically significant difference in the failure rate when comparing angled to straight immediately placed & restored implants. This applies to both anterior and premolar implants

Study of nonlinear viscoelastic mechanical properties of degenerated intervertebral discs / Estudio de las propiedades mecánicas viscoelásticas no lineales de discos intervertebrales degenerados

SUMMARY: Biomechanical factors are important factors in inducing intervertebral disc degeneration, in this paper, the nonlinear viscoelastic mechanical properties of degenerated intervertebral discs were analyzed experimentally. Firstly, the loading and unloading curves of intervertebral discs before and after degeneration at different strain rates were compared to analyze the changes of their apparent viscoelastic mechanical properties; The internal stress/strain distribution of the disc before and after degeneration was then tested by combining digital image technology and fiber grating technology. The results show that the intervertebral disc is strain-rate- dependent whether before or after degeneration; The modulus of elasticity and peak stress of the degenerated disc are significantly reduced, with the modulus of elasticity dropping to 50 % of the normal value and the peak stress decreasing by about 55 %; Degeneration will not change the distribution of the overall internal displacement of the intervertebral disc, but has a greater impact on the superficial and middle AF; The stress in the center of the nucleus pulposus decreases, and the stress in the outer AF increases after degeneration. Degeneration has a great impact on the nonlinear viscoelastic mechanical properties of intervertebral disc, which has reference value for the mechanism, treatment and prevention of clinical degenerative diseases.

RESUMEN: Los factores biomecánicos son importantes en la inducción de la degeneración del disco intervertebral. En este estudio se analizaron experimentalmente las propiedades mecánicas viscoelásticas no lineales de los discos intervertebrales degenerados. En primer lugar se compararon las curvas de carga y descarga de los discos intervertebrales, antes y después de la degeneración, a diferentes velocidades de deformación para analizar los cambios aparentes de sus propiedades mecánicas viscoelásticas. La distribución interna de tensión/deformación del disco antes y después de la degeneración se probó luego combinando tecnología de imagen digital y tecnología de rejilla de fibra. Los resultados mostraron que el disco intervertebral depende de la velocidad de deformación antes o después de la degeneración; El módulo de elasticidad y la tensión máxima del disco degenerado se reducen significativamente, cayendo el módulo de elasticidad al 50 % del valor normal y la tensión máxima disminuyendo en aproximadamente un 55 %; La degeneración no cambiará la distribución del desplazamiento interno general del disco intervertebral, pero tiene un mayor impacto en la FA superficial y media; El estrés en el centro del núcleo pulposo disminuye y el estrés en el FA externo aumenta después de la degeneración. La degeneración tiene un gran impacto en las propiedades mecánicas viscoelásticas no lineales del disco intervertebral, que tiene valor de referencia para el mecanismo, tratamiento y prevención de enfermedades clínicas degenerativas.

Nasal Wall Oriented Implants for All-on-4 Fix-Detachable Maxillary Reconstruction / Implantes nasales orientados a la pared para una reconstrucción maxilar desmontable fija All-on-4

Abstract Immediate loading of full-arch prostheses on dental implants in the upper arch is challenging, as the bone is of low quality and obtaining sufficient torque may be difficult. The purpose of this case report is to describe the rehabilitation of a full- arch by means of placement of four internal tapered connection tilted implants and immediate loading. A 65-year-old man sought dental care with a partially edentulous upper arch. The teeth presented mobility and were extracted. In a second step, two conventional-length implants were placed in the anterior region and two tilted and nasal wall-directed extra-long implants in the posterior region. The insertion torques of 60 N.cm allowed the installation of an immediate prosthesis (hybrid). The clinical case report suggests that the placement of tilted and extra-long implants in the paranasal bone and immediate loading may be a viable option for rehabilitation of the edentulous upper arch.

Resumen La carga inmediata de prótesis de arco completo en implantes dentales en el arco superior es un desafío, ya que el hueso es de baja calidad y puede ser difícil obtener un par suficiente. El propósito de este reporte de un caso es describir la rehabilitación de un arco completo mediante la colocación de cuatro implantes inclinados de conexión cónica interna y carga inmediata. Un hombre de 65 años buscó atención dental con un arco superior parcial sin dientes. Los dientes presentaron movilidad y fueron extraídos. En un segundo paso, se colocaron dos implantes de longitud convencional en la región anterior y dos implantes extralargos inclinados y dirigidos a la pared nasal en la región posterior. Los pares de inserción de 60 N.cm permitieron la instalación de una prótesis inmediata (híbrida). El informe del caso clínico sugiere que la colocación de implantes inclinados y extralargos en el hueso paranasal y la carga inmediata pueden ser una opción viable para la rehabilitación del arco superior desdentado.

Application effect of silica gel stent loading technology in precision microscopic instrument management / 中国实用护理杂志

Objective:To improve the loading technology of precision micro instruments, so as to ensure not only the quality of cleaning and sterilization, but also the safe use of instruments.Methods:From January to March, 2021, 80 sets of precision micro instruments from Sterilization Supply Center, Shanghai Jiao Tong University School of Medicine Affiliated Ruijin Hospital were randomly divided into silica gel pad loading group (group A) and silica gel stent loading group (group B), 40 sets in each group. The cleaning effect, drying effect, loading effectiveness and sterilization wet bag of the instruments in the two groups were compared, and the staff of the disinfection supply center were satisfied with the operation of the loading technology of the instruments in the two groups.Results:The qualified cleaning numbers of the instruments in group A and B were 37 and 39 respectively, and there was no significant difference between the two groups ( χ2 = 1.05, P>0.05). The qualified drying numbers in the group A and B were 29 and 38 respectively, the difference between the two groups was significant ( χ2 = 7.44, P<0.05). The effective number of loading in the group A and B were 30 cases and 39 cases respectively, the difference was significant between the two groups ( χ2 = 8.54, P<0.05). The number of sterilized wet bags in the group A and B were 6 cases and 0 cases respectively, the difference was significant between the two groups ( χ2 = 6.49, P<0.05). The satisfaction of 44 personnel in the disinfection supply center with the operation of loading technology were 36 and 43 respectively, the difference was statistically significant between the two groups ( χ2 = 6.07, P<0.05). Conclusion:Loading precision micro instruments with silica gel stent can not only ensure the cleaning and sterilization quality of instruments, but also make the loading of instruments more safe and stable, greatly improve the working efficiency of instrument treatment and accelerate the turnover efficiency of instruments.

Experimental study of the response of articular cartilage surface roughness to load / 生物医学工程学杂志

Cartilage surface fibrosis is an early sign of osteoarthritis and cartilage surface damage is closely related to load. The purpose of this study was to study the relationship between cartilage surface roughness and load. By applying impact, compression and fatigue loads on fresh porcine articular cartilage, the rough value of cartilage surface was measured at an interval of 10 min each time and the change rule of roughness before and after loading was obtained. It was found that the load increased the roughness of cartilage surface and the increased value was related to the load size. The time of roughness returning to the initial condition was related to the load type and the load size. The impact load had the greatest influence on the roughness of cartilage surface, followed by the severe fatigue load, compression load and mild fatigue load. This article provides reference data for revealing the pathogenesis of early osteoarthritis and preventing and treating articular cartilage diseases.

A Narrative Review of Alveolar Bone Analysis and CBCT Classification related to Immediate Implant Placement in The Anterior Maxilla

@#Immediate implant placement into fresh extraction sockets has gained a lot of attention in implant dentistry. Besides proper risk assessment, the evaluation of tooth anatomy aids the clinicians to select the finest treatment protocol. Cone Beam Computed Tomography (CBCT) imaging was frequently used for alveolar bone analysis prior to tooth extraction in immediate implant placement. As an ideal position is required to prevent a buccally tilted implant or too palatal implant placement, various authors have proposed the treatment guidelines for immediate implant placement in the anterior maxilla. Although insightful, the previous classification was lacking anatomic variant and key anatomical features of alveolar bone and tooth angulation. Furthermore, there is no standardization method of measuring the specific degree of tooth angulation in CBCT scans that could possibly be used in clinical setting for appropriate treatment protocol. Thus, it is essential for the clinician to have adequate knowledge on the role of facial alveolar bone, palatal alveolar bone and tooth angulation related to immediate implant before selecting the appropriate treatment guidelines based on the classification reviewed. In this review, the previous quantitative measurements were categorized, and the previous classification was listed for the sake of familiarity by the dental practitioner with the major updates on implant placement strategy, patient selection and to reduce the rate of surgical complications.

Preparation and physicochemical properties of PVA/HA composite microspheres for embolization / 国际生物医学工程杂志

Objective:To prepare polyvinyl alcohol (PVA) and hydroxyapatite (HA) composite embolization microspheres and investigate their physicochemical properties.Methods:PVA/HA composite embolization microspheres were prepared by reverse suspension polymerization, using PVA and HA as dispersed phases, liquid paraffin containing sorbitan fatty acid ester as the continuous phase, and glutaraldehyde as the cross-linking agent. The morphology, particle size distribution, and microscopic morphology of PVA/HA composite embolization microspheres were observed by optical microscopy and scanning electron microscopy. The chemical structure of PVA/HA composite embolization microspheres and the elasticity, drug loading, and drug release properties of PVA/HA composite bolus microspheres were characterized by Fourier infrared spectroscopy.Results:The PVA/HA composite embolization microspheres were internal, porous round spheres with a particle size distribution of 50-300 μm. The elastic properties of PVA/HA composite embolization microspheres were(13.6±0.145) kPa, which was 2.28 times that of PVA microspheres, and the drug loading capacity and encapsulation efficiency were (76.80±1.22) mg/g and (38.4±12.7)%, respectively. The maximum cumulative release rate of the microspheres within 7 days was (7.37±0.101)%, and the maximum cumulative release was (256.2±9.8) μg.Conclusions:PVA/HA composite embolization microspheres have good mechanical properties and drug-loading and drug-releasing properties, which provide an important reference for their use as medical devices.

The Role of Exosomes in Force-Related Periodontal Inflammatory Response / 医用生物力学

Exosomes are extracellular vesicles secreted by cells with a variety of molecular components, which can play the role of substance transport and signal communication between cells through autocrine and paracrine. Exosomes exist widely in vivo and participate in many physiological and pathological processes, including force-related periodontal inflammation. There are stress receptor cells in the periodontium, which can sense force loading on the tooth. An appropriate amount of mechanical loading can maintain health of the periodontium, while excessive mechanical loading may cause destruction and absorption of the periodontium, leading to periodontal inflammation. This article reviews the role of exosomes in force-related inflammation response, especially in periodontal inflammation response.