Resultado de las sobredentaduras superiores según número de implantes dentales en pacientes edéntulos totales / Outcome of maxillary overdentures according to the number of dental implants in full edentulous patients

RESUMEN Objetivo: Realizar una revisión de la literatura sobre el resultado de las sobredentaduras maxilares según el número de implantes dentales en pacientes edéntulos totales. Materiales y Métodos: Se realizó una búsqueda bibliográfica sistematizada en los motores de búsqueda Pubmed, Scopus y Web of Science y luego de establecer los criterios y filtros de la misma, se utilizaron 6 artículos. De los 6 artículos analizados, 4 fueron estudios de tipo ensayo clínico aleatorizado, 1 estudio prospectivo y 1 estudio retrospectivo. Resultados: Los resultados clínicos de las sobredentaduras maxilares, basados en el número de implantes sobre los cuales fueron soportadas, y comparando los protocolos más difundidos e investigados como los de All-on-4 y All-on-6, fueron similares. Se consideran óptimos, confiables, exitosos y longevos, sin diferencia significativa según el número de implantes dentales colocados. Conclusiones: Las sobredentaduras maxilares soportadas por 4 o 6 implantes fueron técnicas de tratamiento confiables, y ofrecen resultados comparables. Las complicaciones fueron limitadas y los resultados óptimos y duraderos.

ABSTRACT Objective: To review the literature on the outcome of maxillary overdentures according to the number of dental implants in edentulous patients. Materials and Methods: A systematic bibliographic search was carried out in the Pubmed, Scopus and Web of Science search engines and, after appliying the criteria and filters, 6 articles were used. Of the 6 articles analyzed, 4 were randomized clinical trial type studies, 1 prospective study and 1 retrospective study. Results: The results of maxillary overdentures, according to the number of implants used to support them, and comparing the most widespread and researched protocols such as All-on-4 and All-on-6, were similar. They are considered optimal, reliable, successful and long-lived, with no significant difference within the number of dental implants placed. Conclusions: Maxillary overdentures supported by 4 or 6 implants were reliable, and exhibit comparable results. The complications were limited, and the results were optimal and enduring.

Resultado de las sobredentaduras superiores según número de implantes dentales en pacientes edéntulos totales / dental implants

Objetivo: Realizar una revisión de la literatura sobre el resultado de las sobredentaduras maxilares según el número de implantes dentales en pacientes edéntulos totales. Materiales y Métodos: Se realizó una búsqueda bibliográfica sistematizada en los motores de búsqueda Pubmed, Scopus y Web of Science y luego de establecer los criterios y filtros de la misma, se utilizaron 6 artículos. De los 6 artículos analizados, 4 fueron estudios de tipo ensayo clínico aleatorizado, 1 estudio prospectivo y 1 estudio retrospectivo. Resultados: Los resultados clínicos de las sobredentaduras maxilares, basados en el número de implantes sobre los cuales fueron soportadas, y comparando los protocolos más difundidos e investigados como los de All-on-4 y All-on-6, fueron similares. Se consideran óptimos, confiables, exitosos y longevos, sin diferencia significativa según el número de implantes dentales colocados. Conclusiones: Las sobredentaduras maxilares soportadas por 4 o 6 implantes fueron técnicas de tratamiento confiables, y ofrecen resultados comparables. Las complicaciones fueron limitadas y los resultados óptimos y duraderos.

Objective: To review the literature on the outcome of maxillary overdentures according to the number of dental implants in edentulous patients. Materials and Methods: A systematic bibliographic search was carried out in the Pubmed, Scopus and Web of Science search engines and, after appliying the criteria and filters, 6 articles were used. Of the 6 articles analyzed, 4 were randomized clinical trial type studies, 1 prospective study and 1 retrospective study. Results: The results of maxillary overdentures, according to the number of implants used to support them, and comparing the most widespread and researched protocols such as All-on-4 and All-on-6, were similar. They are considered optimal, reliable, successful and long-lived, with no significant difference within the number of dental implants placed. Conclusions: Maxillary overdentures supported by 4 or 6 implants were reliable, and exhibit comparable results. The complications were limited, and the results were optimal and enduring.

Implante Inmediato en Zona Estética Anterior con Pérdida Parcial de la Cortical Vestibular: Reporte De Caso y Revisión de Literatura

El tratamiento con implantes dentales hoy en día es un procedimiento clínico de rutina que permite rehabilitar a los pacientes con prótesis fijas. En este caso presentamos un tratamiento complejo de implantación inmediata del sector anterior con pérdida parcial de la cortical vestibular en el que se realizó una regeneración ósea guiada y provisionalización en un tiempo quirúrgico en un paciente con patología renal. Complementamos el estudio con una revisión de la efectividad de las técnicas utilizadas y las posibles respuestas celular asociadas a la patología renal.

Treatment with dental implants nowadays is a routine clinical procedure that allows patient rehabilitation with fixed prostheses. In this case we present a complex treatment of immediate implantation of the anterior sector with partial loss of the vestibular cortex, in which guided bone regeneration and provisionalization was performed in surgical time in a patient with kidney pathology. The study was complemented with a review of the effectiveness of the techniques used and the possible cellular responses associated with kidney pathology.

Orientações de manutenção e higienização de prótese fixa total implantossuportada: revisão de literatura / Guidelines for maintenance and cleaning of implantssupported total fixed prosthesis: literature review

A evolução dos tratamentos em implantodontia possibilitou uma mudança nos tratamentos reabilitadores para pacientes edêntulos, tornando possível a colocação de próteses fixas, que proporcionam maior qualidade de vida para estes pacientes. Para que estas próteses tenham bom desempenho e longevidade satisfatórios é essencial que se mantenha um padrão adequado de higienização bucal e manutenção profissional. Assim, o objetivo deste trabalho foi realizar uma revisão de literatura a respeito dos principais recursos disponíveis para higienização e manutenção das próteses totais fixas sobre implante (protocolo de Branemark), tanto nos cuidados domiciliares dos pacientes quanto no atendimento profissional do cirurgião dentista. Foi realizada uma busca eletrônica, não sistemática, nas bases de dados Lilacs, Pubmed/Medline, Scielo e ScienceDirect, cruzando-se os seguintes descritores: "Higiene Oral"; "Implantes Dentários"; "Implantação Dentária"; "Manutenção"; "Prótese Dentária Fixada por Implante" e "Prótese Dentária". Foram consultados artigos de revisão de literatura, revisão sistemática, meta-análise, estudos clínicos randomizados, além de livros pertinentes ao assunto, publicados no período de 1995 a 2022.Verificou-se na literatura disponível que os principais instrumentos indicados para uso domiciliar são escova dental, fio dental, escova interdental, irrigador oral, dentifrício e enxaguatório. No atendimento profissional em consultório odontológico deve ser dispendida atenção especial às instruções passadas ao paciente e também fazer o possível para motivar e encorajar o seu engajamento na rotina de higienização, além do acompanhamento periodontal, possíveis substituições de parafusos e instalação de placa oclusal estabilizadora, quando necessário. Manter uma higiene oral adequada é essencial para o sucesso das próteses fixas sobre implantes e o cirurgião dentista desempenha um papel crucial não apenas ao realizar o acompanhamento periódico do paciente, mas também ao sugerir os instrumentos mais apropriados, instruir sobre a higiene oral adequada e motivar o paciente a manter a saúde bucal satisfatória(AU)

The evolution of treatments in implantology has enable a change in rehabilitation treatments for edentulous patients, making it possible to place fixed prostheses that provide a better quality of life for these patients. In order to ensure good performance and satisfactory longevity, it is essential to maintain an appropriate standard of oral hygiene and professional maintenance. Thus, the objective of this work was to conduct a literature review on the main resources available for cleaning and maintenance of complete fixed prostheses on implants (Branemark protocol), both in the patients' home care and in the professional care provided by the dentist. A nonsystematic electronic search was carried out in the Lilacs, Pubmed/Medline, Scielo, and ScienceDirect databases, crossing the following descriptors: "Oral Hygiene"; "Dental Implants"; "Dental Implantation"; "Maintenance"; "Dental Prosthesis, ImplantSupported"; and "Prosthodontics". Literature review articles, systematic reviews, meta-analyses, randomized clinical studies, and relevant books on the subject published from 1995 to 2022 were consulted. The literature available indicates that the main instruments recommended for home care are toothbrush, dental floss, interdental brush, oral irrigator, toothpaste, and mouthwash. In the professional dental office, special attention should be given to the instructions given to the patient, as well as to motivate and encourage their engagement in the hygiene routine, in addition to periodontal monitoring, possible screw replacements, and installation of an occlusal splint when necessary. Maintaining adequate oral hygiene is essential for the success of fixed prostheses on implants, and the dentist plays a crucial role, not only in providing periodic patient follow-up, but also in suggesting the most appropriate instruments, instructing on adequate oral hygiene, and motivating the patient to maintain satisfactory oral health(AU)

Reconstrucción auricular con implantes mastoideos utilizando el sistema Novaloc / Implant supported auricular reconstruction using the Novaloc system

La microtia es un padecimiento congénito de etiología desconocida que se puede presentar asociado a síndromes, su frecuencia es mayor en hombres, tiene predilección por el oído derecho. Se han propuesto distintas alternativas de tratamiento tanto estéticas como funcionales que disminuyan riesgos y aumenten la calidad de vida de los pacientes. Entre los tratamientos más comunes se encuentra el injerto costocondral, siendo una alternativa viable, aunque de mayor riesgo y que puede necesitar varios procedimientos quirúrgicos con el fin de lograr el mejor resultado estético; por lo mismo, uno de los tratamientos más realizados actualmente, es la reconstrucción auricular con implantes osteointegrados que se colocan en la región mastoidea y soportan una prótesis auricular. Se presenta el caso de un paciente masculino quien fue rehabilitado con implantes mastoideos ostoeintegrados para reconstrucción auricular implantosoportada. Las prótesis implantosoportadas reducen la necesidad de realizar cirugías correctivas y posibilitan la buena higiene de la prótesis al ser ésta removible, pero sin sacrificar su estabilidad. Los sistemas más utilizados son los mismos que se emplean en sobredentaduras, ya que el diseño del aditamento transmucoso, se adapta perfectamente al grosor del epitelio en la región mastoidea, por lo que es una excelente alternativa de tratamiento (AU)

Microtia is a congenital condition of unknown etiology that can occur associated with syndromes. Its frequency is greater in men and has a predilection for the right ear. Different treatment alternatives, both aesthetic and functional, have been proposed that reduce risks and increase the quality of life of patients. Among the most common treatments can be found the costochondral graft being a good alternative although greater risk of failure and the probability of several surgeries to get the best aesthetic result. Because of that one of the most used treatments is the placement of osseointegrated implants that can hold a prosthetic ear. Here is a case of a male patient who was rehabilitated with osseointegrated mastoid implants for ear reconstruction. Implant-supported prostheses significantly reduce the number of surgeries that must be performed and is a good option to maintain excellent hygiene as the prosthetic ear is removable, without compromising stability. The most common system is the same as those used in overdentures since the design of the transmucosal attachment fits perfectly to the thickness of epithelium in mastoid region (AU)

Cochleo-carotid dehiscence as a third window syndrome: a review of an unusual presentation and its clinical-radiological approach

When examining patients who present both fluctuating auditory symptoms and vestibular symptoms, which can be mistaken for an ear disease, it is important to consider cochlear-carotid fistula as a condition that could generate these clinical manifestations. In this case, additional imaging tests should be performed to demonstrate the lack of continuity at that level and rule out other entities. The objective is to describe the cochleo-carotid dehiscence in a 39-year-old woman and propose it as a possible etiology of a third window syndrome, in order to discuss the relationship between clinical findings, neurotologic examination, and magnetic resonance imaging.

Al examinar a pacientes que presentan síntomas auditivos fluctuantes y síntomas vestibu-lares, que pueden ser confundidos con una enfermedad del oído, es importante considerar la fístula coclear-carotídea como una condición que podría generar estas manifestaciones clínicas. En este caso, se deben realizar pruebas de imagen adicionales para demostrar la falta de continuidad en ese nivel y descartar otras entidades. El objetivo es describir la dehiscencia cocleo-carotídea en una mujer de 39 años y proponerla como una posible etiología del síndrome de la tercera ventana, con el fin de discutir la relación entre los hallazgos clínicos, el examen neurotológico y la resonancia magnética.

Periradicular and Peri-Implant Lesions Associated with Apical Impact of Osseointegrated Implants in Tooth Roots: Clinical Case Reports

This clinical case report aims to describe the development of periradicular and perimplant cystic lesions resulted from the intimate contact of the apical region of osseointegrated implants of dental roots, and discuss the reasons fo r failure of the guided bone regeneration procedure associated with platelet rich fibrin and leukocytes, this process was used to the treatment of the first case. Case Reports. Three cases were reported, two cases described the close contact between the tooth roots and the osseointegrated implants and another with a distance of 1.08 mm. All cases realized a radiographic, and they had not periapical lesions before contact with the apical region of the osseointegrated implants on the roots of the teeth. In the case with the largest cystic extension, the procedure was: removal of the osseointegrated implant with apicectomy of the neighboring teeth, excisional biopsy of the lesion, and grafting using the technique of guided bone regeneration associated with L-PRF. All three cases, endodontic treatment was performed on the neighboring teeth within 2 years of survival of the osseointegrated implants in order to reverse the existing lesion. Results. The diagnostic hypothesis of the three cases was periradicular and peri-implant lesion, arising from a contact of the apical region of the osseointegrated implant with the adja cent tooth. The distance of 1.08 mm between the apices did not ensure normality of the periradicular and peri-implant tissues. The intimate contact caused lesions of different extents and root fractures. Conclusion. Premature contact of the osseointegrated implant with the root region of the neighboring tooth may lead to the development of periradicular and peri-implant lesions, suggesting that it is not possible to control this infectious process with endodontic treatment of the injured tooth.

Este reporte de caso clínico tuvo como objetivo describir el desarrollo de lesiones quísticas perirradiculares y periimplantarias resultantes del contacto íntimo de la región apical de implantes osteointegrados de raíces dentales, y además discutir las razones del fracaso del procedimiento de regeneración ósea guiada asociado a fibrina rica en plaquetas y leucocitos. Este proceso se utilizó para el tratamiento del primer caso. Se reportaron tres casos, en dos casos se describieron el estrecho contacto entre las raíces de los dientes y los implantes osteointegrados y en el otro se determinó una distancia de 1,08 mm. En los tres casos se realizó una radiografía y se determinó que no existían lesiones periapicales, antes del contacto con la región apical de los implantes osteointegrados, en las raíces de los dientes. En el caso de mayor extensión quística, el procedimiento fue: extracción del implante osteointegrado con apicectomía de los dientes vecinos, biopsia excisional de la lesión e injerto mediante la técnica de regeneración ósea guiada asociada a L-PRF. En los tres casos, el tratamiento de endodoncia se realizó en los dientes vecinos dentro de los 2 años de supervivencia de los implantes osteointegrados para revertir la lesión existente. La hipótesis diagnóstica de los tres casos fue lesión perirradicular y periimplantaria, originada por un contacto de la región apical del implante osteointegrado con el diente adyacente. La distancia de 1,08 mm entre los ápices no aseguraba la normalidad de los tejidos perirradiculares y periimplantarios. El contacto íntimo provocó lesiones de diferente extensión y fracturas radiculares. El contacto prematuro del implante osteointegrado con la región radicular del diente vecino puede conducir al desarrollo de lesiones perirradiculares y periimplantarias, lo que sugiere que no es posible controlar este proceso infeccioso con tratamiento endodóntico del diente lesionado.

Evaluation of the treatment effect on sinus elevation and implant restoration in cases with odontogenic maxillary sinusitis after tooth extraction / 口腔疾病防治

Objective@#To investigate the clinical effects of sinus elevation surgery and implant restorationdue to insufficient bone massafter tooth extraction in patients with odontogenic maxillary sinusitis (OMS) and to provide a reference for use in clinical practice.@*Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. Forty-five teeth were extracted from patients with OMS in the maxillary posterior area (the study group). Sinus elevation and implantation were performed due to insufficient bone height in the implant area 6-8 months after tooth extraction in the study group. Forty-eight teeth were extracted from patients without "OMS" in the maxillary posterior area (the control group), and sinus elevation and implantation were performed due to insufficient bone height in the implant area 6-8 months after tooth extraction inthe control group. In the study group, 13 cases of discontinuous maxillary sinus floor bone and residual alveolar bone height of the maxillary sinus floor less than 4 mm were addressed with lateral wall sinus elevation, and the other 32 cases were addressed with crest-approach sinus elevation. In the control group, 8 cases of residual alveolar bone height less than 4 mm in the maxillary sinus floor were addressed with lateral wall sinus,and the other 40 cases were addressed with crest approach sinus elevation. Restorations were placed 6 to 8 months after surgery. The patients were followed up 21 days, 3 months, and 8 months after implantation and every 6 months after the placement of the restorations. The sinus bone gain (SBG), apical bone height (ABL) and marginal bone loss (MBL) were statistically analyzed 24 months after the restoration.@*Results@#The average preoperative mucosal thickness in the 45 patients in the study group was (1.556 ± 0.693) mm, which was significantly larger than that in the control group (1.229 ± 0.425) mm (P<0.001). There were no perforations in either group. Twenty-four months after restoration, there was no significant difference in the SBG, ABH or MBL between the two groups (P>0.05).@*Conclusion@#After the extraction of teeth from patients with OMS, the inflammation of the maxillary sinus decreased, and the bone height and density in the edentulous area were restored to a certain degree. The effects of sinus floor lifting surgery and implant restoration do not differ between patients with and without OMS.

Clinical evaluation of autonomous robot assisted implant surgery:A retrospective clinical study / 实用口腔医学杂志

Objective:To retrospectively evaluate the clinical outcomes of autonomous dental implant robot(ADIR)assisted implant surgery in 1-year follow-up.Methods:20 patients with tooth missing underwent implantation surgery by ADIR were incuded.The plat-form deviation,apex deviation and angular deviation of the implants were analyzed.The marginal bone height and peri-implant soft tis-sue health were measured and observed immediately,6 months and 12 months after the restoration.Results:The platform deviation,apex deviation and angular deviation of 20 implants at the 3 follow-up examinations were(0.34±0.11)mm,(0.34±0.15)mm and(0.82°±0.38°),respectively.There was no significant difference in the accuracy of different implant diameter and length(P＞0.05).During the follow-up period,all implants had successful osseointegration,stable marginal bone height,and acceptable peri-implant soft tissue condition.Conclusion:The 1-year follow-up indicates that ADIR can achieve promising clinical performance.Long-term follow-up studies are still necessary for verification.

Exploration of the characteristics of peri-implant microenvironment in rats based on bioinformatics analysis / 实用口腔医学杂志

Objective:To explore the differences of microenviroment between peri-implant tissue and oral mucosal tissue.Methods:The gene chip data GSE43744 was downloaded from the GEO database,bioinformatics tools were used to analyze the differentially ex-pressed genes between the peri-implant tissue and normal oral mucosal tissue in rat.Results:1315 differentially expressed important genes,including 797 upregulated genes and 518 downregulated genes,were screened out.Gene enrichment analysis showed that com-pared with normal oral mucosal tissue,the gene expression of innate immune activity,cell activation,inflammatory response,and func-tional expression related to external and bacterial stimuli in peri-implant tissue were significantly upregulated,while that of extracellular matrix tissue,adhesion,extracellular matrix polysaccharides,response to mechanical stimuli and response to toxic substances was sig-nificantly downregulated.Meanwhile,multiple molecular functions and biological pathways related to T cells were highly expressed,which may play an important role in the peri-implant microenvironment.In addition,PPI network was constructed,and screened 7 core genes including FCER1G,TYROBP,PTPRC,ITGB2,AIF1,EMR1 and RAC2,which may be target genes for studying peri-implant microenvironment.Conclusion:There is a significant difference of microenvironment characteristics between peri-implant tissue and o-ral mucosa.The target genes screened using PPI network may be the key to future research on the peri-implant microenvironment.

The Correlation between Speech Fluency and Diadochokinetic Rate in Children Aged 7～11 Years with Cochlear Implantation / 听力学及言语疾病杂志

Objective To explore the correlation between speech fluency and diadochokinetic rate in children aged 7～11 years with cochlear implant.Methods Speech samples were collected from 62 children aged 7～11 years with cochlear implant using language retelling task and diadochokinetic rate test task.Their speech rate,articulation rate,syllable duration and pause duration were analyzed.The data were input into ICF converter to obtain the im-pairment limit of each parameter and analyze the speech fluency and diadochokinetic rate characteristics.Partial cor-relation analysis was performed for speech rate,articulation rate,syllable duration and pause duration by two tasks.Results ① For children with cochlear implant,the mean ICF impairment limit of diadochokinetic rate was 1.3± 0.1,the mean ICF impairment limit of fluency in retelling was 1.0±0.3,with various degree of impairment in both tasks.② There was a moderate or low correlation between speech rate,articulation rate,syllable duration in retell-ing task and those in diadochokinetic rate task(0.3＜|r |≤0.8).There was a low correlation between pause dura-tion in retelling task and speech rate and pause duration in diadochokinetic rate task(0.3＜|r |≤0.5).Conclusion The speech fluency and diadochokinetic rate of children aged 7～11 years with cochlear implant is underdeveloped,and the poor articulation movement ability limits their development of speech fluency.

The Effects of the Intelligent Hearing-assistive System on Hearing Benefits to Cochlear Implant Recipients / 听力学及言语疾病杂志

Objective To study the effects of the intelligent hearing-assistive system incorporated in Nuro-tron cochlear implants(CI),including the autonomic acoustic scene recognition(ASR),intelligent strategy config-uration as well as the objective and subjective hearing improvements on recipients.Methods ① To evaluate the per-formance of the ASR matule,in a sound-proof room,the preset five kinds of test audios,including speech,noise,speech in noise,pure music(without human voice)and non-pure Music(with human voice)were played.Each type of scenes included 6 to 9 5 min test files.The prediction accuracy and scene switching times were calculated.② In order to evaluate the noise-reduction performance of the ABeam technology in the speech enhancement module,13 Nurotron? CI recipients were recruited and their speech recognition rate when ABeam was"ON"and"OFF"with noise coming from 90°,180°or 270°were tested,individually.Also,their subjective hearing feedback was evaluated through visual analogue scale(VAS)evaluation.Results The ASR module achieved high prediction performance,with prediction accuracy 99％±4％,96％±9％,94％±12％,94％±15％,92％±13％for speech,noise,noisy speech,pure music and non-pure music,respectively.The scene transation times for each individual scene were 1.1 ±0.3,1.4±0.7,1.3±0.5,1.4±0.8 and 1.3±0.5,indicating that the prediction was also stable.When noise came from the sides and behind of recipients and speech signal from the front,the adaptive dual microphone noise re-duction algorithm ABeam significantly increased the speech recognition score(SRS)in 5 dB signal-to-noise(SNR)environment(P＜0.001),with an average increase of 15.92％.Especially when the noise came from 180 degree backward,the SRS increased 28.68％when ABeam was"0N",which was significantly higher than when ABeam was"OFF"(P＜0.01).Conclusion The intelligent hearing-assistive system can help CI recipients automatically configure appropriate SPSs under different environments,improving the speech intelligibility and hearing comfort.

Finite element analysis of the effect of the distribution position and content of bone cement on the stress and displacement of reverse femoral intertrochanteric fracture / 中国组织工程研究

BACKGROUND:The proximal femoral nail antirotation is the preferred treatment for reverse osteoporotic intertrochanteric fractures.Bone cement enhancement can reduce the probability of proximal femoral nail antirotation cut-out and cut-through,but there are no relevant biomechanical studies demonstrating the effect of bone cement content and location on the stress and displacement of the fracture end. OBJECTIVE:To investigate the effects of different contents and locations of bone cement in cement-reinforced proximal femoral nail antirotation on stress,strain,and displacement of reverse osteoporotic femoral intertrochanteric fractures in the elderly by finite element analysis. METHODS:A healthy adult female right femur model was extracted by Mimics software and smoothed in Geometric software.Five types of internal fixation methods of proximal femoral nail antirotation(cementless,cephalic spherical 1 mL,cephalic spherical 2 mL,cephalic spherical 3.4 mL,and cylindrical 5 mL around spiral blade)and femoral intertrochanteric fracture(AO subtype 31-A3.1 type)model were established in Solidworks software.After assembly,the total stress distribution,peak stress and displacement of the five models of implants with the femur were compared in Ansys software. RESULTS AND CONCLUSION:(1)The peak stresses of proximal femoral nail antirotation with head-end spherical 1 mL,head-end spherical 2 mL,head-end spherical 3.4 mL,and cylindrical 5 mL enhanced proximal femoral nail antirotation around the spiral blade respectively were 571.07 MPa(located at the junction of the spiral blade and the main nail),495.45 MPa(located at the junction of the spiral blade and the main nail),467.20 MPa(located at the junction of the main nail and the distal screw connection),642.70 MPa(located at the junction of the main nail and distal screw connection),and 458.58 MPa(located at the junction of the spiral blade and the main nail).(2)The maximum displacements of proximal femoral nail antirotation with head end sphere 1 mL,head end sphere 2 mL,head end sphere 3.4 mL,and with cylindrical 5 mL enhancement around the spiral blade were 9.260 5,7.589 1,7.316 8,6.790 7,and 6.615 7 mm,respectively,all of which were located at the proximal end of the femoral head.(3)These findings revealed that for reverse femoral intertrochanteric fractures treated with proximal femoral nail antirotation,the bone cement enhancement had significant mechanical stability compared with no enhancement,and the enhancement of the spiral blade 5 mL around the perimeter was the best,which is more preferable for aged unstable intertrochanteric fractures.

Exosome-loaded injectable hydrogel for repairing bone defects around implants / 中国组织工程研究

BACKGROUND:A large number of studies have confirmed that exosomes can promote osteogenesis and vascularization.However,simple exosome therapy has problems such as poor targeting,and the content of loaded molecules cannot reach the therapeutic concentration. OBJECTIVE:To load exosomes into injectable gluconolactone-sodium alginate β-tricalcium phosphate-polyethylene glycol hydrogel,and observe the effect of the hydrogel on peri-implant bone defect in vivo and in vitro. METHODS:Exosomes were extracted from bone marrow mesenchymal stem cells and wrapped in injectable gluconolactone-sodium alginate β-tricalcium phosphate-polyethylene glycol hydrogel.(1)In vitro experiment:The hydrogel loaded with exosomes and the hydrogel without exosomes were cocultured with endothelial progenitor cells,and exosomes uptake experiment,tubule formation experiment,cell proliferation,migration ability,and angiogenic gene detection were carried out.(2)In vivo experiment:Twelve male New Zealand white rabbits were used to prepare two standard implant cavities and corresponding bone defects in the long axis of one femur.A hydrogel loaded with exosomes was implanted in the bone defect after an implant was implanted in a cavity at the proximal end of the implant(experimental group),and an unloaded exosome hydrogel was implanted in the bone defect after an implant was implanted in a cavity at the distal end of the implant(control group).At 3,6 and 9 weeks after operation,bone defects with implants were removed and stained with hematoxylin-eosin staining and Masson staining.Simultaneously,osteogenic and angiogenic genes were detected at 9 weeks after operation. RESULTS AND CONCLUSION:(1)In vitro experiment:Exosomes could enter endothelial progenitor cells.The proliferation,migration,angiogenesis and gene(CD31,vascular endothelial growth factor and basic fibroblast growth factor)expression of endothelial progenitor cells in the hydrogel-loaded group were higher than those in the hydrogel-unloaded group(P<0.05).(2)In vivo experiment:Hematoxylin-eosin staining and Masson staining showed that at 3 weeks after operation,only a small amount of new bone was found in the two groups,and the material was partially degraded.At 6 weeks after operation,the amount of new bone in the two groups increased,and a large amount of new bone was found in the experimental group,with obvious calcium deposition.At 9 weeks after operation,compared with the control group,a large number of bone trabeculae thicker than mature were found in the experimental group,calcium salt deposition was more obvious,and a large number of osteoblasts were found around the bone trabeculae.The protein expressions of CD31,vascular endothelial growth factor,basic fibroblast growth factor,bone morphogenetic protein 2,type I collagen and osteocalcin in the experimental group were higher than those in the control group at 9 weeks after operation(P<0.05).(3)The exosome-loaded gluconolactone-sodium alginate β-tricalcium phosphate-polyethylene glycol hydrogel could promote the proliferation,migration and angiogenic differentiation of endothelial progenitor cells and promote the repair and regeneration of bone defects around implants.

Finite element analysis of the influence of scaffold materials on the fixed restoration of edentulous maxillary implants under two designs / 中国组织工程研究

BACKGROUND:In the treatment of edentulous maxillary implants supported fixed repair,the selection of upper scaffold structure materials and the design of different distal implant implantation methods have a close influence on the long-term stability of the whole mouth implant repair. OBJECTIVE:To comprehensively explore the influence of three different materials of upper scaffold and two implant fixation designs on the biomechanics of the fixed maxillary implant repair based on the three-dimensional finite element method. METHODS:Based on the conical beam CT data of a healthy adult with normal jaws,the Mimics software was used to separate the maxillary and maxillary dentin three-dimensional solid models,and the Geomagic Studio software was used to construct the three-dimensional finite element model of denture with denture implant and fixed maxillary arch combined with specific model parameters.According to the different designs of distal implants in the maxillary posterior region,two scheme models were established.Scheme 1(Design 1)was designed in accordance with the"All-on-4"design used in clinical practice.Two implants were vertically implanted in the bilateral incisor region of the maxilla,and the other two implants were implanted in the bilateral second premolar region at a 30° angle.In scheme 2(Design 2),two implants were vertically implanted in the lateral incisor region of the maxilla,and two short implants were vertically implanted in the posterior region of the maxilla in the bilateral second premolar region.Three materials(titanium,zirconia and polyether ether ketone)were used to assign values to the upper scaffold structure in the two designs,and six different models were obtained.The biomechanical effects of the implant,surrounding bone tissue and the upper scaffold structure were compared and analyzed in the oblique loading direction. RESULTS AND CONCLUSION:(1)The maximum stress peaks of all models were distributed in the neck region around the posterior implant and the cortical bone under the two edentulous implant fixed restoration schemes,regardless of the material of the upper scaffold.(2)Compared with the alternative design of Design 2,which adopted vertical implantation of short implants,Design 1 showed a more ideal stress distribution on the maxilla.(3)The scaffold model constructed by polyether ether ketone material transferred higher stress to the implant and surrounding bone tissue close to the loading zone of the upper jaw bone,followed by titanium and zirconia.As for the support itself,the peak stress of the upper scaffold of polyether ether ketone was significantly lower than that of the zirconia and titanium scaffolds.Zirconia scaffolds were used among the three upper scaffolds to disperse the stress distribution of implant and bone tissue.(4)The results suggest that both designs can be applied to clinical practice.However,from the perspective of biomechanics,the stress distribution of the implant,surrounding bone tissue and upper scaffold in Design 1 is more rational,which is more conducive to the long-term prognosis of fixed implant repair in patients with edentulous jaws.The upper scaffold material has a certain influence on the stress distribution of the implant-bone interface.

Biomechanical difference between resin ceramic crown and zirconia all-ceramic crown implant restorations in three occlusal relationships / 中国组织工程研究

BACKGROUND:In implant restoration in the aesthetic area,zirconium dioxide is gradually becoming the most commonly used upper restorative material and has achieved better clinical results.Resin-ceramic composite,a new type of dental restorative material,begins to try to be used as an upper restorative material in implant restoration,but there is less research on the application of this material in implant restoration. OBJECTIVE:To compare the biomechanical differences between resin ceramic crowns and zirconia all-ceramic crown implant restorations in three occlusal relationships for restoring maxillary central incisors. METHODS:The cone-beam CT image data of a patient with single-crown implant restoration of maxillary central incisor were selected,and the maxillary bone model was extracted by using Mimics 21.0 software,and the model was imported into Solidworks 2020 software.The crown,adhesive,abutment,central screw,and implant were modeled,and the model of single-crown implant restoration of maxillary central incisor was assembled.After giving the model material property parameters(resin-ceramic composite and zirconia for the upper restoration materials)in ANSYS Workbench 2021 R1 software,three occlusal relationships(edge-to-edge occlusion,normal overjet and deep overbite)were simulated and loaded to analyze the stress distribution of the resin-ceramic crown and zirconia all-ceramic crown implant restoration models. RESULTS AND CONCLUSION:(1)The stress concentration areas in the implant restoration models of the resin-ceramic crown group and the zirconia all-ceramic crown group in different occlusal relationships were distributed in the upper restoration loading point,the abutment-implant connection,the implant neck and the surrounding bone tissue.As the occlusal relationship changed from the edge-to-edge to normal and deep overbite,the peak equivalent forces of the restorative abutment,central screw,implant,and bone tissue in both the resin-ceramic and zirconia all-ceramic crown groups gradually decreased.The highest peak equivalent forces were observed for the upper restorations in deep overbite.The zirconia all-ceramic crown group had the highest peak equivalent force in the adhesive layer in the edge-to-edge relationship,and the resin-ceramic crown group had the highest peak equivalent force in the adhesive layer in the deep overbite.(2)In the edge-to-edge occlusion,the peak equivalent force of the adhesive layer and central screw in the resin-ceramic crown group was slightly smaller than that in the zirconia all-ceramic crown group,and there was no significant difference between the two groups in the peak equivalent force at the upper restoration,restoration abutment,implant,and bone tissue.The peak stresses in the upper restoration,adhesive layer,and central screw of the resin-ceramic crown group were slightly less than those of the zirconia all-ceramic crown group at normal fit,and there were no significant differences between the two groups in the peak equivalent forces at the restoration abutment,implant,and bone tissue.In deep overbite,the peak adhesive,abutment,and central screw stresses were greater in the resin-ceramic crown group than in the zirconia all-ceramic crown group,with no significant differences in the upper restorations,implants,or bone tissue.(3)The results showed that the upper restorative material had no significant effect on the stress distribution of the implant and bone tissue,and had some effects on the stress distribution of the upper restoration,adhesive,restoration abutment,and central screw,but the difference was not significant.The occlusal relationship has a significant influence on the stress distribution in all structures and bone tissue of the implant restoration.The resin-ceramic crowns have a buffering effect on the stresses in the case of edge-to-edge and normal occlusion.

Application of metal-organic frameworks in implant surface modification / 中国组织工程研究

BACKGROUND:In recent years,metal-organic frameworks have been widely used in the biomedical field because of their unique properties,and metal-organic frameworks can be applied to implant surface modification for improving their biological properties and the surgery's success rate. OBJECTIVE:To introduce metal-organic frameworks commonly used in implant surface modification and the preparation and action mechanism of surgical implants modified by metal-organic frameworks. METHODS:The articles concerning metal-organic frameworks used in implant surface modification published from 2010 to 2023 were searched on PubMed,Web of Science and CNKI.Finally,64 articles were included for review. RESULTS AND CONCLUSION:(1)Metal-organic frameworks have the properties of high porosity,large specific surface area,and diverse spatial structure.As bioactive material,metal-organic frameworks have attracted much attention in tissue engineering and regenerative medicine.(2)The metal-organic frameworks commonly used in the field of implant surface modification include three types.Zeolitic imidazolate frameworks are commonly used as carriers,carrying various drugs and biomolecules.The MIL series are suitable for drug carriers and nanoenzymes.Bio-metal-organic frameworks have many applications because of their diverse structure and are characterized by excellent biosafety.(3)The preparation of implant materials modified by metal-organic frameworks can be mainly divided into two types:one is to incorporate metal-organic frameworks into pretreated implants;the other is to synthesize metal-organic frameworks in situ on pretreated implants.(4)Metal-organic frameworks on the implant surface could release their components,load drugs,catalyze active reactions,or combine with other materials,giving implants antibacterial and anti-inflammatory characteristics and promoting osseointegration.The preparation method of metal-organic framework coatings needs further improvement,and the metabolism and distribution of metal-organic framework coatings should be deeply explored,and its clinical application should be actively promoted.

Angiogenesis mechanism of metal ions and their application in bone tissue engineering / 中国组织工程研究

BACKGROUND:Owing to excellent angiogenesis activity and their participation in the physiological processes such as angiogenesis in osteogenesis,the researches and applications of a variety of metal ions are getting deeper in the field of bone tissue engineering. OBJECTIVE:To systematically explain the mechanism of angiogenesis of different metal ions such as copper ion(Cu2+),magnesium ion(Mg2+),strontium ion(Sr2+),zinc ion(Zn2+),cobalt ion(Co2+)and their current research situation as well as application in the treatment of diseases in the field of bone tissue engineering. METHODS:The two authors used PubMed and CNKI to search the literature published between 2017 and 2022 with the search terms"copper ion,magnesium ion,strontium ion,zinc ion,cobalt ion,bone,angiogenesis"in Chinese and"copper,cuprum,Cu,magnesium,Mg,strontium,Sr,zinc,Zn,cobalt,Co,metal ion,angiogenesis,bone"in English.After reading titles and abstracts,the articles were initially screened,and irrelevant articles were excluded.Finally,114 articles were included for review. RESULTS AND CONCLUSION:(1)Metal ions can regulate angiogenesis by acting on vascular endothelial growth factors,hypoxia-inducible factors,angiogenesis-related genes,endothelial cells and conducting immune regulation of macrophages.(2)Metal ions such as copper,magnesium,strontium,zinc and cobalt are often used to improve the performance of tissue engineering scaffolds due to their significant angiogenic effect.Among them,hydrogels,bioceramics and synthetic polymer materials are widely used at present,and magnesium and its alloys also have advantages due to their excellent bearing capacity.However,these materials all have some defects.Currently,there is no ideal bone replacement material.(3)Various metal ions show different application potentials in bone replacement materials:Copper has antibacterial,angiogenic and osteogenic properties,and is mainly used for bone defects caused by infection and tumors.Magnesium and zinc have strong biodegradability,so the degradation rate should be controlled.Magnesium is corrosive and is mainly used as an alloy.The angiogenesis mechanism of zinc is less involved.Magnesium and strontium are effective in treating osteoporotic bone defects.(4)The above five metal ions(copper,magnesium,strontium,zinc and cobalt)have a significant role in promoting angiogenesis and then promote osteogenesis through angiogenesis.Some ions,such as copper ions,have a bactericidal effect.These ions can be used as a new strategy for the treatment of bone defects caused by tumors,osteoporosis,infection and trauma,but the current clinical trials and application studies of products are relatively insufficient.

Restoration of a dental defect in a patient with ectodermal dysplasia: a case report and literature review / 口腔疾病防治

Objective@#To explore the treatment options for congenitally missing teeth in patients with ectodermal dysplasia and provide a clinical reference.@*Methods@#A patient with ectodermal dysplasia with a concave midface, anterior protrusion of the chin, and underdevelopment of the lower third of the face presented with congenital loss of multiple maxillary teeth, malocclusion of the remaining teeth, congenital loss of mandibular dentition, small dental arches, and upper and lower alveolar bone hypoplasia. The patient was treated by means of a removable partial maxillary prosthesis, implants in the anterior region of the lower mandible designed with the assistance of digital guides, and bar-clamped implant-overlay prostheses. A literature review of the protocol for the treatment of this condition was also conducted.@*Results@#In addition to good retention and stability after denture wear, an excellent occlusal relationship, improvement of the patient's facial appearance, including upper and lower lip fullness, more equal balancing of the lower and middle 1/3 of the face, and improved masticatory function were achieved. The results of the literature review showed that patients with ectodermal dysplasia who are congenitally edentulous usually have a complex intraoral situation that makes restoration difficult, and common restorative modalities for these patients include fixed bridges, removable partial dentures, complete dentures, overdentures, and implant prostheses, which need to be selected according to the actual intraoral situation of each patient. Currently, there is no consensus on the treatment of congenitally missing teeth in patients with ectodermal dysplasia, and some scholars have suggested that fixed restorations be recommended for patients with fewer missing teeth, while the option of removable or implant-covered denture restorations should be given to patients with more missing teeth, with removeable prostheses for underage patients that are replaced with permanent fixed prostheses when the jaws have stabilized.@*Conclusion@#In patients with ectodermal dysplasia with congenital tooth loss, all factors should be taken into account, and an individualized restorative plan should be developed.

Accuracy of digital guided implant surgery: expert consensus on nonsurgical factors and their treatments / 口腔疾病防治

@#The standardized workflow of computer-aided static guided implant surgery includes preoperative examination, data acquisition, guide design, guide fabrication and surgery. Errors may occur at each step, leading to irreversible cumulative effects and thus impacting the accuracy of implant placement. However, clinicians tend to focus on factors causing errors in surgical operations, ignoring the possibility of irreversible errors in nonstandard guided surgery. Based on the clinical practice of domestic experts and research progress at home and abroad, this paper summarizes the sources of errors in guided implant surgery from the perspectives of preoperative inspection, data collection, guide designing and manufacturing and describes strategies to resolve errors so as to gain expert consensus. Consensus recommendation: 1. Preoperative considerations: the appropriate implant guide type should be selected according to the patient's oral condition before surgery, and a retaining screw-assisted support guide should be selected if necessary. 2. Data acquisition should be standardized as much as possible, including beam CT and extraoral scanning. CBCT performed with the patient’s head fixed and with a small field of view is recommended. For patients with metal prostheses inside the mouth, a registration marker guide should be used, and the ambient temperature and light of the external oral scanner should be reasonably controlled. 3. Optimization of computer-aided design: it is recommended to select a handle-guided planting system and a closed metal sleeve and to register images by overlapping markers. Properly designing the retaining screws, extending the support structure of the guide plate and increasing the length of the guide section are methods to feasibly reduce the incidence of surgical errors. 4. Improving computer-aided production: it is also crucial to set the best printing parameters according to different printing technologies and to choose the most appropriate postprocessing procedures.